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THE

RAY SOCIETY.

INSTITUTED MDCCCXL1V.

L O N 1) O N

MDCCCLXII.

r

ZW

7?

ON THE

GERMINATION, DEVELOPMENT, ANT)
FRUCTIFICATION

or THE

HIGHER CRYPTOGAMIA,

AND

ON THE FEUCTIFICATION OF THE

CONIFERS.

BY

Dr. WILHELM IIOFMEISTER.

TRANSLATED BY

FREDERICK CURREY, M.A., F.R.S., Sec. L.S.

LONDON:
PUBLISHED FOR THE RAY SOCIETY, BY

ROBERT HAEDWICKE, 192, PICCADILLY.

MDCCCLXII.

<fr

PRINTED BY J. K. ADLARD, BARTHOLOMEW CLOSE.

TRANSLATOR'S PREFACE.

The work of which the following pages contain a trans-
lation has not yet been published in Germany, and a few
words are necessary to explain its nature and origin. It
is founded mainly upon the author's well-known treatise on
the higher Cryptogamia, which appeared at Leipzig in
1851. ShiGe that period Dr. Hofmeister has continued
his valuable researches, and the results of his observations
have been published in the 4th and 5th volumes of the
'Transactions of the Royal Academy of Saxony,' in the
Reports of the same Academy for' the year 1854, and in
the ' Regensburg Flora ' for the same year. In addition
to the matter relating to the Cryptogamia, the original
treatise also contained some remarks on the fructification
of the Coniferee, and on the analogies between the sexual
phenomena in mosses and vascular cryptogams on the one
side, and the conifers on the other. Dr. Hofmeister
has since published further observations upon this latter
subject in the ' Regensburg Flora' for 1854, and in the
first volume of ' Prino'sheim's Jahrbucher fur wissen-
schaftliche Botanik.'

At the request of the Council of the Ray Society, and

VI TRANSLATORS PREFACE.

for the purposes of the present translation, Dr. Hofmeister
undertook to combine all the above publications into one
uniform whole, revising the text throughout, and adding
a quantity of matter existing in manuscript, being the
results of his subsequent researches. Dr. Hofmeister's
object has been to render his work a complete record of all
that is at present known of the subjects to which it relates,
and the translator feels confident that this object has been
fully attained.

TABLE OF CONTENTS.

CHAPTER I.

PAGE
ANTHOCEROS LjEVXS AND PUNCTATUS . . 1

Vegetation of Anthoceros, 1 — 7 ; cell-multiplication in the stem of Antho-
ceros, 3—7; chlorophyll bodies, 5—7; organs of fructification of
Anthoceros, 7 — 18; formation of antheridia in Anthoceros, 7—9;
escape of the antherozoids, 9 ; formation of the archegonia in Antho-
ceros, 9 ; their impregnation, 9 ; their development into the fruit,
10, 11; cell-development in the young fruit, 11 — 14; the so-called
calyptra, 13; the columella, 13, 14; formation of the spore-mother-
cells, 14 — 17; spores, 17, 18; reproduction of Anthoceros by buds,
18; observations of Mohl, Nageli, and Schacht on the development
of the spores of Anthoceros, 18, 19; reference to figures of Antho-
ceros, 19 ; observations of Nees von Esenbeck, Bischoff, and Schacht
on the fructification of Anthoceros, 19.

CHAPTER II.

LEAFLESS JUNGERMANNLE . . . .21

(Pellia epiphjlla, Aneura pin-guis and multifida, Metzgeriu f areata.)

Structure of the spores of Pellia ejriphylla, 21 ; their germination, 21, 22 ;
vegetation of Pellia epiphylla, and cell-multiplication in the stem and
shoots, 22 — 29 ; production of roots, 23, 24 ; formation of hairs, 24 ;
production of shoots, 26—28 ; production of antheridia, 29, 30, and
spermatozoids, 30, 31; production of archegonia, 31—34; perianth,
33 ; impregnation, 34 ; development of the fruit, 34 — 39 ; formation
of elaters and spore-mother-cells, 38 ; production of spores, 39 — 41 ;
vegetation of Metzgeria /areata, 41 — 43 ; cell-multiplication in its
stem, 41 ; development of shoots in Metzgeria /areata, 41, 42; small
size of its chlorophyll-granules, 42; development of adventitious
shoots, 42; production of fructiferous leaves or lateral axes, 43;
antheridia and archegonia, 43 ; development of stem and shoots in
Aneura, 43, 44 ; production of archegonia, 44, 45 ; development of
the fruit, 45 ; development of antheridia, 45, 46 ; production of buds
by Aneura multifida, 46.

Vlll TABLE OF CONTENTS.

CHAPTER III.

PAGE
LEAFY JUNGERMANNISE . . . .47

Gradual transition from leafless to leafy Juugermaunise, 47; Blasia pusilla,
a remarkable transition form, 47; its stem, shoots, and leaves, 47, 48;
its reproductive buds, 48 ; cell-multiplication in the terminal bud of
Blasia pusilla, 49; its reproductive buds and bud-receptacles/50, 51 ;
spores of Frullania dilatata, 51 ; their germination, 51, 52 ; spores of
Jungermannia bicuspidata, 52 ; their germination, 52 — 54; germination
of Jungermannia divaricala, Alicularia scalaris, Sarcoscyphus Funkii,
and Jungermannia cremdala, 54; germination of Lophocolea hetero-
phylla, 54, 55; spores of Sad/da complanata, 55; their germination,
55, 56; cell-multiplication in the end of the stem of leafy Junger-
mannise, Frullania dilatata, Lophocolea bidentata, Trichocolea tomen-
lella, and Jungermannia bicuspidata, 5G, 57; in Jungermannia connivens
and divaricala, 57; the forms of the leaves of Jungermannia?, 57, 58;
origin of the leaf of Fossombronia pusilla, 58 ; appendages of
the leaves of Lophocolea, 58, 59 ; growth of the teeth of leaves
of Lophocolea heterophylla, 59 ; leaf-development in Jungermannia
bicuspidata, connivens and divaricala, 59, 60 ; in Ptilidium ciliare,
60; development of the leaf of Frullania dilatata, 61 — 63; of
Radula complanata, 63 ; leaves of Jungermannia curta and crenulata,
and Alicularia scalaris, 63 ; general observations on leaf-develop-
ment in Jungermannise, 63, 64; mode of ramification of the Junger-
mannise, 64, 65 ; half-subterraneous shoots of Haplomitrium Hookeri,
regarded by Gottsche as its roots, 64, 65 ; development of antheridia
of Liverworts, 65 — 67; cell-division in antheridia of Madotheca
platyphylla, Fossombronia pusilla, and Lophocolea heterophylla, 65 ;
formation of spermatozoa in Liverworts, 66 ; peculiar formation of
antheridium of Madotheca platyphylla, 67 ; sizes of spermatozoa in
leafy Jungerinarmise, 67 ; development of archegonia of leafy Liver-
worts, 67 — 72 ; calyx or perianth of Liverworts, 68 — 71 ; in Radula
complanata, 68 ; in Jungermannia bicuspidata and divaricala, and
Fndlania dilatata, 69; in Alicularia scalaris, 69, 70; abnormal
perianth of Calypogeia Trichomanes, 70, 71 ; development of the
germinal vesicle in Fossombronia pusilla, 71, 72 ; proportion of fruit
to archegonia and antheridia, 72, 73 ; development of fruit in Jun-
germauuiae, 73 — 83 ; cell-development in the fruit of Jungermanniae,
74, 75 ; cell-development in that of /. divaricala, 75, 76 ; elaters of
/. divaricala, 75, 76; cell-multiplication and production of elaters in
Jungermannia biscuspidala and trichophylla, Radula complanata,
Lophocolea heterophylla, Alicularia scalaris, and Calypogeia Tricho-
manes, _ 77, 78 ; development of fruit of Frullania dilatata, 78, 79 ,
formation of the calyptra in Liverworts, 79, 83 ; individualisa-
tion of the elaters and spore-mother cells, 81—83; Hedwig's in-
vestigations of the germination of spores of Jungermannise, 83 ;
Nees von Esenbeck on the same subject, 83 ; Bischoff on the germina-
tion of Pellia, S3 ; Gottsche's observations on the spores oiPellia, and
on the germination of Blasia pusilla, 83; Gottsche on the germination
of Jungermannia crenulata, 84 ; Gronland's investigations on the
germination of leafy Jungermannise, 84 ; Nageli's observations on
cell-multiplication in the stems of Jungermannise, 84, 85; Nees von
Esenbeck and Gottsche on the ramification of Jungermannise, and
Goltsche's statements regarding the development of the leaf in

TABLE OF CONTENTS. IX

PAGE

Haplomitrium Hookeri, 85 ; Hedwig's determination of the structure
of the archegonia of Jungermanniae, 85, 86 ; fruit of Jungermanniae
observed by Gottsche, Schniidel, and Hedwig, 86 ; development of
their spores observed by H. von Mold, 86 ; membrane of the elater
seen by Schmidel in Aneura multifield, 86 ; Gottsche's observa-
tions on the elaters and perianth of Jungermanniae, 87 ; Schmidel's
discovery of self-motile bodies in the antheridia of Fossombronia
pusilla, 87 ; figures and descriptions of antheridia and spermatozoids
of Jungermanniaj given by various authors, 87 ; Gottsche's observa-
tions on the antheridia of Haplomitrium Hookeri, 88.

CHAPTER IV.

RICCIA AND RIELLA 89

The germ-plant of Riccia glauca and the arrangement and multiplication of
its cells, 89 ; vegetation of Riccia glauca, 90 — 93 ; its leaves, 92 ; de-
velopment of its organs of fructification, 93 — 97; antheridia, 94;
archegonia, 96 — 96 ; development and maturation of the fruit, 96 ;
production of gemma? in Riccia glauca, 97.; Lindenberg's observa-
tions on Riccia, 97; Riella, 97; peculiar habit of Riella {Duriena) heli-
coplylla, 98 ; germ-plants of Riella Reuteri, 98 ; vegetation of Riella
Reuteri, 98, 99 ; development of its leaves, 99 ; succession of its
shoots, 99 ; development of antheridia and archegonia in Riella
Reuteri, 99, 100; impregnation and development of its fruit and
spores, 100, 101.

CHAPTER V.

MARCHANTIEAE AND TARGION1E.E .... 1Q2

{Marchantia polymorphs, Fegatella conica, Rebouillia hemispherica,
Lunularia vulgaris, Targionia hypophylla.)

Vegetation of the above plants, 102—112; formation of each new shoot
by the amalgamation of three shoots, 102 ; development of rudiments
of spring shoots of Fegatella conica in the preceding October, 102,
note ; mode of growth of the shoots of Marchantieae and Targioniece,
103 — 104 ; their ramification, 104 ; formation of buds or bulbils in
Lunularia and Marchantia, ]04 — 107; vegetation of the buds, 107,
108 ; second mode of production of shoots in Lunularia, Mar-
chantia, Targionia, Rebouillia, and Fegatella, 108, 109 ; structure
and development of the leaves of Marchantieae, 109, 110 ; stomata
and air-cavities of Marchantieae, 110, 111 ; inflorescence of Mar-
chantieae, 111 — 114; development of the fructiferous shoot, 112 ; in
Rebouillia hemispherica, 112, 113 ; receptacles, 113 ; those of Rebou-
illia hemispherica producing usually only four archegonia, 113 ; produc-
tion of archegonia in Marchantieae, 113 ; condition of the tissues of
the receptacle in the neighbourhood of impregnated archegonia, 113,
114; growth of the young fruit of Rebouillia, 114; archegonia of
Fegatella conica, 114, 115 ; archegonia of Marchantia polymorpha,
115, 116; air-cavities of the receptacle of Marchantia polymarpha,

TABLE OF CONTENTS.

PAGE

117,118; development of archegonia in Targionia hypophy Ha, 118,
119 ; fruit of Targionia, 119; spore-mother-cells and elaters of Tar-
gionia, 120; development of antheridia in Marchantia polymorpha,
120 — 122; spermatozoids of Marchantia, 122 ; antheridia of Rebou-
illia hemispherica, 122; Historical resume: — Bischoff's work on the
Marchantieae, 122 ; Nees von Esenbeck on Marchantieae, 122 ;
Gottsche, on Marchantieae, 123 ; observations on fructification of
Marchantia, by Micheli, Dillenius, Iiupp, and Linnaeus, 123;
SchmidePs observations on Marchantieae, 123 ; Hedwigon the antheridia
and fruit, 123; Mirbel's work on Marchantia polymorpha, 123 — 126;
von Mold on the cells of the stomata of Marchantia, 124; Nageli on
gemmae of Marchantia, 124; ramification of Marchantia, described by
Nees von Esenbeck as dichotomous, 125 ; Bischoff on the impregna-
tion of Lunularia, and on the germ-plants of Marchantieae, 126,
127 ; Gottsche and Gtonland on the germination of Preissia commu-
tata, 127; Gronland on the germination of Lunularia and Marchantia,
127; Henfrey on the development of spores and elaters in Mar-
chantia polymorpha, 127 ; observations on the spermatozoids of
Marchantia, by Unger and Meyer, 127, 128 ; Thuret's figures of
spermatozoids of Marchantieae, 128.

CHAPTER VI.

MOSSES 129

Mode of growth of the stems of mosses, 129 ; cell-multiplication in the
stem of Sphagnum, 129 — 135 ; Nageli's observations on this subject,
130, 131, note; pitted cells in Sphagnum, 134; phyllotaxis in Sphag-
mim, 135 — 137 ; observations of Braun and Schimper on this subject,
136, note; lateral shoots si Sphagnum, 137 — 139; Schimper's views
on the ramification of the branches of Sphagnum, 138, 139; develop-
ment of the stem and branches in Orthotrichum affine, 139 ; develop-
ment of the leaves in Sphagnum, 139 — 142 ; Nageli's observations on
cell-development in the leaves of Sphagnum, 140, 141, note ; annular and
spiral threads in cells of the leaf of Sphagnum, 142 ; development of
the leaves of Phascum, Bryum, Hypnum, and Polytrichum in agree-
ment with that in Sphagnum, 142, 143 ; formation of the pocket at the
base of the leaf, 143, 144 ; development of the leaf of Fissidens, 143 — '
146 ; chlorophyll bodies in the leaves of Fissidens and Phascum cus-
pidatum, 146, 147 ; Nageli's views on chlorophyll bodies discussed,
146; those of Von Mold, Arthur Gris, and Sachs, 146, 147; views
of Nageli and Schleiden on the development of the leaves of mosses,
147 ; fruit-bearing branches of mosses, 148 ; development of the arche-
gonia of mosses, 148 — 152 ; development of the antheridia of mosses,
152, 153 ; their bursting, and escape of the spermatozoids, 153 ; burst-
ing of the antheridium of Funaria hygrometrica, 153, 154; motion of
the spermatozoids of Funaria and Polytrichum formosum, 154 ; develop-
ment of antheridia of Sphagnum, 154, 155 ; spermatozoids of Sphagnum,
155 ; Schleiden's erroneous views of the structure of the antheridium
in Sphagnum, 155 ; impregnation of mosses, 155, 156; development of
the fruit of mosses, 156 — 168 ; fruit of Funaria hygrometrica and
Gymnostomum pyriforme, 157, 158; production of the vaginula, 159;
production of spore-mother-cells, 160 — 164 ; production of the spores
of mosses, 164, 165 ; fruit of Gymnostomum pyriforme, 165 , spore-

TABLE OF CONTENTS. XI

VAGE

mother-cells of Funaria hygrometrica, 167 ; formation of spores of
Funaria, 167, 168; fructification of Archidium phascoides, ]68 — 170;
its deviations from the ordinary type in mosses, 168, 169 ; its anthe-
ridia and spermatozoids and archegonia, 169 ; development of its
fruit, 169, 170 ; Schimper's explanation of the nature of the ripe fruit,
169, note ; germination of the spores of mosses, 170 — 175 ; production
of the pro-embryo, 171 — 174; Schimper's observations on the ger-
mination of spores of Sphagnum in water ; distinction of the pro-em-
bryos of mosses from the prothallia of ferns, 174, 175. Historical
resume: — Hedwig's observations on the sexual reproduction of
mosses, 175, 176 ; development of the leafy axis from the pro-embryo
explained by Kageli, 176; Nageli's results extended by Schimper, 176 ;
Unger the discoverer of spermatozoids in mosses, 176, 177; indica-
tion of spermatozoids in the observations of Bischoff, Schmidel, and
Nees von Esenbeck, 176, note ; Schleiden's erroneous statement re-
garding the structure of the antheridia refuted by Schimper, ] 77 ;
Schimper's observations on the archegonia of mosses, 177 ; Valen-
tine's description of the rudimentary cell of the moss-fruit, 177 — 179 ;
development of the moss-capsule first accurately described by Von
Mohl, 179 ; observations on the development of the fruit and spores
of mosses, by Bischoff, Von Mohl, and Lantzius-Beninga, 179, 180;
Bruch's observations, 180; abnormal fruits observed by Gumbel, 180,
181 ; possibility of hybridization suggested by Bayrhoffer, 181.

CHAPTER VII.

FERNS 182

Their germination, 182 — 185 ; the first rootlet, 183 ; formation of the
prothallium, 183 — 185 ; the turning away of the prothallium from the
light, 183 ; formation of antheridia, 185, 186 ; differences in prothallia
and antheridia of certain Polypodiacese, 186, 187; Wigaud ou the
occurrence of spermatozoids and their mother-cells in vegetative cells
of the prothallium, 187, note ; cell-development in the antheridia, 188 ;
production of spermatozoids, 388, 189; observations of authors on
the spermatozoids of ferns, 189, note; production of the archegonia,
189 — 197; number and position of the archegonia, 192, 193; pro-
duction of the germinal vesicle, 193 ; abortive nature of most of the
archegonia on a prothallium, 195, 196 ; growth of sterile prothallia of
ferns, 196, 197 ; production of shoots by abortive prothallia, 197; great
number of antheridia produced by shoots of prothallia, 197 ; pecu-
liarities of old abortive prothallia of Gymnogramma chrysophylla, 197,
198 ; impregnation of the archegonia, 198, 199 ; development of the
archegonia after impregnation, 198 — 201 ; production of the embryo,
200, 201; development of the embryo, 201—207; formation of
the first frond, 202, 203 ; the first root of the young fern, 203—205 ;
adhesion of the embryo to the prothallium, 205, 206 ; influence of the
growth of the embryo upon cell-multiplication in the prothallium, 206,
207 ; Von Mercklin's supposed observation of dark striped vessels in
the prothallium, 207, note; development of the second frond, 207 ;
Fteris aquilina and Aspidiumfilix-mas examples of two extreme types of
growth, 208 ; vegetation of Fteris aquilina, 208—226; growth of the

Xll TABLE OF CONTENTS.

PAGE

frond, 208—210 ; formation of the pinnae, 209, 210 ; growth of the
first root, 210, 211; growth of the primary axis, 211; growth
of the stem-bud and fronds, 211 — 214; structure of the stem
and formation of the vascular bundles, 213 — 222 ; formation
of new fronds, 221 — 223; development of roots, 223, 224;
ramification of roots, 224; increase of the tendency to furca-
tion in terminal bud with the age of the shoot, 224; unbranched,
frondless, terminal shoots, 224, 225 ; position of buds from which
new shoots are produced, 225, 226 ; vegetation of Aspidium filix-mas,
226 — 245 ; production of first frond, 226 ; second and following
fronds, 227 ; rapid increase in thickness of the stem beyond the
fifth or sixth frond, 227; cell-multiplication in the terminal bud,
227, 228 ; arrangement of the fronds, 228 ; production of first
vascular bundles, 228, 229; growth of Aspidium filix-mas in the
second year, 229 ; production of roots in the mature plant from
vascular bundles of the stipes, 229, 230 ; production of vascular
bundles in the stem, 230 — 232 ; form and development of the apical-
cell, 232 — 239; table of measurements of apical cells in Aspidium filix-
mas, Aspidium spinulosum, and Asplenium filix-femina, 233 ; relations
of base and sides of apical cell in various states of Aspidium filix-mas,
234 — 236 ; irregularly shaped apical-cells of Aspidium filix-mas and
Aspidium spinulosum, 236 ; explanation of the facts connected with
the apical cell, 236—239 ; coincidence of two-edged form of apical cell
and bilinear arrangement of fronds in various ferns, 239; cell-succession
in apex of leaf-buds of flowering plants, 239, 240 ; table of measure-
ments of apical cells,240; cell-succession in the terminal bud oiAspidium
filix-mas and Aspidium spinulosum, 241; mucilage surrounding the bud,
242 ; development of scales on the terminal bud, 242,243 ; Kunze on
the bodies at the base of the stipes in Hemitelia capensis, 2±'3,note;
development of frond in Aspidium filix-mas, 243 ; formation of roots,
243, 244; rarity of furcation of the terminal bud in Aspidium filix-mas,
244; adventitious buds in Aspidium filix-mas and Aspidium spinulosum,
245; Schleiden's supposed axillary buds, 245, «o/e; vegetation ot Asplenium
filix-femina, Asplenium Bellangeri, Struthiopteris Germanica, Nephrolepis
undulata and N. splendens, 245 — 248 ; peculiarities in the growth of
Asplenium filix-femina, 246 ; development of adventitious buds and
furcation of the stem in that fern, 247 ; adventitious shoots of Stru-
thiopteris Germanica, 247 ; production of adventitious buds on the
frond of Asplenium Bellangeri, 247 ; development of runners iu
Nephrolepis, 247, 248 ; vegetation of Polypodium and Niphobolus,
248 — 251 ; two-edged form of apical cell and bilinear arrangement of
fronds in Niphobolus and Polypodium, 248 ; not occurring in Poly-
podium vulgare, 248 ; growth of P. vulgare and Bryopteris, 248 —
249 ; formation of the stipes and development of scales in the above
ferns, 249 ; development of the fronds, 249 — 251 ; scales at the base
of the fronds, 251; vascular bundles and roots, 251; vegetation of
Platycerium alcicorne, 251 — 254; development of the fronds, 251 —
253 ; structure of the stem and roots, 253 ; form of the apical cell,
253; vegetation of Marallia cicutafolia, 254—256; statements of
De Vriese and Hartig on the devolopment of the Marattiaceae,
254, note ; form of the apical cell, 254 ; growth of the fronds, 254,
255; development of the Perula, 255; development of scales and
roots, 255 ; development of new plants from fragments of Marattia
cicutcefolia, 255, 256 ; development of the fruit and spores of ferns,
250,257. Historical review : — 257 — 266; reproduction of ferns by

TABLE OF CONTENTS. Xlll

PAGE

spores first indicated by Morison, 257 ; Ehrhart's observation of the
two-lobed leaf preceding the perfect fern, 257; germination of spores
of ferns, first accurately observed by Kaulfuss, 257 ; sexual organs of
prothallium, discovered by Bischoff, 257, 258 ; antheridia and sper-
matozoids, discovered by Nageli, 258 ; Nageli's observation of the
archegonia, 258 ; real nature of the archegonia first ascertained by
Suminski, 258, 259; Wigand on the sexual organs of ferns, 259;
observations of Hofmeister confirmatory ^of Suminski's results, 260;
Schacht on the archegonia aud impregnation of ferns, 2G0, 261 ;
Von Mercklin on the same subject, and his observation of the
entrance of the spermatozoid into the archegonia, 261 ; Mettenius'
observations, 261 ; Henfry on the sexual reproduction of ferns, 261 ;
further statements by Hofmeister and Wigand on the same subject,
261,262; anatomy of fern-stem, first clearly explained by Von
Mohl, 262 ; Brogniart on the ramification of ferns, 262 ; his views,
supported by Hofmeister and Steuzel, 262 ; opposed by Karsten and
Mettenius, 263 ; views of Pringsheim and Irmisch adopted by Hof-
meister, 263 — 266.

CHAPTER VIII.

EaUISETACE^E 267

{Equisetum arvense, pratense, variegatum, hyemale, palmtre, and limosmi.)

Growth of the stem of Equisetum, 267 — 269; Cramer on cell-succession
in the end of the stem, 267, note; production of the leaf, 269, 270;
production of the teeth of the edge of the leaf, 270, 271 ; relation of
the cells of the pith to those of the outer layers of the stem, 271 —
273 ; formation of the epidermis, 273 ; differentiation of the vascular
bundles, 273 — 275; separation of the cells of the pith, 275 ; ramifica-
tion caused entirely by adventitious buds and their mode of growth,
275 — 278; formation of adventitious roots in Equiseta growing in
damp situations, 278 — 280 ; fructification of Equisetaceae, 280 — 288 ;
development of spore-mother-cells, 281 — 286 ; elaters, 287 — 289 ;
spores, 2S8 — 290; Sanio's observations on abnormal formation of
elaters, 291 ; evolution of the spores, 291, 292 ; formation of the pro-
thallium, 292, 293 ; male and female prothallia, 293 ; formation of
antheridia, 293, 294; spermatozoids, 294 — 296; obstacles to the
germination of Equisetacese, 296, 297; female prothallia, 297; Bis-
choff's observation of antheridia and archegonia on the same prothal-
lium of E. syloaticum, 297, note; observations on the production of
male and female prothallia, 297, 298 ; formation of archegonia, 298 —
300; impregnation, 300; development of the impregnated arche-
gonium, 300, 301 ; development of the embryo, 301 — 303; formation
of the stem, 303 ; development of adventitious buds, 303, 304. His-
torical Review : — Observations of Vaucher and Agardh on the germina-
tion of the spores of Equisetacese, 304, 305 ; Bischoff's observations
on the same subject, 305, 306; first account of the antheridia given
by Thuret, 306 ; archegonia discovered by Bischoff, 306 ; observations
of Milde and Hofmeister on the sexual organs of Equisetacese, 306.

Xiv TABLE OF CONTENTS.

CHAPTER IX.

PAGE

ophioglossejE . . . • .30/

Germination and development of Botrychium Unarm, Sw:— Underground
germination of this plant, 307 ; structure of the prothallia, 307, 308 ;
production of antheridia and archegonia, 308 ; development of the
embryo 308, 309 ; Roper's notion of the growth of Botrychium, 309,
310 • modified by Presl, Mettenius, and subsequently by Roper, 310 ;
Braun on the growth of Ophioglossum, 310; Schacht's assertion that
Botrychium is reproduced only by adventitious buds, 310 ; production
of fronds in Botrychium, 311, 312; Roper's observations on ramifica-
tions of stems of Botrychium in loose, sandy ground, 312, note; vege-
tation of Ophioglossum vulgatum, 312—315 ; development and arrange-
ment of the fronds, 313, 314; form of the apical cell, 314; develop-
ment of vascular bundles and roots, 314, 315 ; relation of fertile and
sterile fronds, 31 5 ; observations of Mettenius on the germination of
Ophioglossum pedunculosum, 315—317; its prothallia, 315, 316; pro-
duction of antheridia and archegonia, 316 ; development of the em-
bryo, 316, 317.

CHAPTER X.

PILULABJA GLOBULIFEB.A AND MINUTA ; MAKSILEA PTJBESCENS . 318

Fruit of Pilularia, 318—321; development of spore-mother-cells, 319;
formation of the macrospores, 319, 320 ; formation of the micro-
spores, 320; dispersion of the spores, 321 ; germination of the macro-
spores, 321, 322; development of the prothallium and pro-embryo,
and formation of the archegonia, 322 ; production of spermatozoids
from the microspores, 322, 323 ; development of the embryo, 323—
325 ; structure and germination of the large spore of Marsilea pubes-
cens, 325, 326 ; formation of the prothallium and archegonium,
326, 327: failure of experiments with the small spores, 327.

CHAPTER XI.

SALYINIA NATANS 328

Structure of the large ripe spores, 328 ; production of the prothallium,
328, 329 ; formation of the archegonia, 329, 330 ; development of
the microspores aud production of spermatozoids from them, 330 — ■
332; development of the impregnated archegonium and formation of
the embryo, 332 — 334 ; production of vascular bundles, 334 ; infertility
of prothallia kept from microsporangia, 334. Historical review: —
Confusion produced in regard to the germination of Rhizocarpese by
Schleiden's ' Grundziige,' 335; observations of Nageli, Mettenius,
and Hofmeister on this subject, 335.

TABLE OF CONTENTS. XV

CHAPTER XII.

PAGE
ISOETES LACUSTRIS . . 336

Importance of the study of the development of the Isoeteae in botanical
morphology, 336 ; peculiar phenomena in the growth of these plants
indicated by Von Mold, 336, 337 ; observations on the arrangement
of the fronds of young plants, by A. Braun, 337 ; structure of the
spore described by Mettenius, 337 ; Karl Midler's account of the
germination of Isoetes lacustris, and observations of Mettenius on the
same subject, 337 ; form and structure of the microspores of Isoetes
lacustris, 338, 339 ; Roper and Schleiden on the supposed presence
of carbonate of lime in the exosporium, 338 ; evolution of the spores,
339 ; formation of the prothallium, 339, 340 ; production of arche-
gonia, 340, 341 ; microspores of Isoetes lacustris, 341 ; production of
spermatozoids by them, 341 — 343 ; observation of Mettenius on the
slow motion of the spermatozoids, 342, note ; development of the
embryo, 843 — 345 ; production of the first leaf, 345, 346; develop-
ment of the scale, 347 ; formation of the sheath, 347 ; growth of the
primary axis, 347 ; formation of the first root, 348, 349 ; develop-
ment of subsequent roots, 350 — 355 ; experiments on the germina-
tion of spores, 351 ; arrangement of the leaves, 354 ; structure of the
stem in the germ- plant, 356; formation and development of cam-
bium, 356, 357; growth of bark, 357 — 358; formation of roots of
the second year, 358 — 360; ramification of the roots, 360; sub-
sequent growth of the plant, 360, 361 ; effect of the annual
renovalion of the cambial layer, 361, 362 ; scalariform arrangement
of cells in the leaves, 362 ; periodicity in the production of sterile
and fertile leaves in Isoetes, 362—363; origin of the scales of the
leaves, 363, 364; production of the sporangia of Isoetes lacustris,
364—367 ; spore-mother-cells, 365, 366 ; furrows of the underside
of the stems in Isoetes, 367; differences of growth connected with
the presence of one furrow or more under the stem, 367 — 370 ; re-
semblance of Isoetes in its mode of reproduction to the Conifers, 370 ;
spores of Isoetes favorable to the observation of the peculiar mode
of reproduction by macro- and microspores, 370, 371 ; distinction of
germination of Isoetes from that of vascular cryptogams with green
prothallia, 371 ; agreement of Isoetes with Lycopods, both in vegeta-
tion and fructification, 371, 372 ; annually renewed cambium-layer,
peculiar to Isoetes among vascular cryptogams, 372 ; general observa-
tions on the stem and roots of Isoetes, 372.

CHAPTER XIV.

SELAGINELLA ... . 373

Growth of the end of the stem in species of Selaginella, with 2|
arrangement of leaves, 373—376 ; formation of the leaves, 376 —
380; production of a flat cellular body (stipule) from the upper
side of the base of the leaf, observed by R. Midler, 378 ; structure
of the stipule, 378, 379 ; production of papillae at the margins of
the leaves, 378, 379 ; furcation of the apex of the stem, 380—382 ;

XVI TABLE OF CONTENTS.

PAGE

unequal development of the forks of the stem in some species, 381 ;
their equal development in others, 381, 382; structure of the stem,

382, 383; production of adventitious roots from the forks of the stem,

383, 384; production of new plants from fragments of the stem of
Selaginella, 384 ; fructiferous shoots of Selaginella, 384. 385 ; produc-
tion of the sporangia, 385 — 392 ; views of Bischoff and VouMohlon the
nature of the sporangia of Selaginella, 387 ; differentiation of the
macrosporangia and microsporangia, 387 ; development of the macro-
sporangia, 387 — 389 ; production of the macrospores, 388 — 390 ;
differences iu certain species, 389, 390 ; development of the micro-
spores ; formation of rudiments of prothallia from macrospores before
the bursting of the macrosporangia, 391, 392 ; Mettenius on the de-
velopment of the cells of the prothallium, 392, note ; uncertainty as to
the first stages of development of the prothallium, 392, 393 ; dormancy
of the macrospores of Selaginella hortensis and S. Helvetica, 393 ;
germination of macrospores, 393 ; formation of archegonia, 393, 394 ;
production of spermatozoids from the microspores, 394, 395 ; cause
of want of success iu experiments ou sowing spores of Selaginellce,
295 ; only one archegonium usually impregnated on the prothallium,
395 ; development of the pro-embryo, 395, 396 ; development of
the embryo, 396, 397; greater resemblance of Lj/copodium in its mode
of growth to Polypodiacese than to Selaginella, 398 ; growth of Psilo-
tum triquetrum, 398 ; remarks on the reproduction of Lycopodiacese
with spores of only one kind, 398, 399 ; De Bary's observations on
the spores of Lycopodium inundatum, 399. Historical review : — 399.

CHAPTER XV.

CONIFERS 400

Structure of the ovules of Conifera, 400, 401 ; development of the pollen
of the Conifera?, 401 — 406 ; peculiar ceil-niultiplicatiou in the free
pollen-cells of Coniferee, 404, 405 ; structure of the pollen of the
Abietinese explained by Fritzsche and Schacht, 405, note ; passage of
the pollen through the micropyle of the ovule to the nucleus and
formation of pollen-tubes, 406 ; resemblance of the pollen of Ephedra
to that of Larir, 406, note; development of the endosperm, 406 —
409 ; development of the endosperm in Taxus, 409, 410 ; production
of the corpusculum in Coniferse, 410 — 414; statements of Mirbel and
Spach as to the contents of the corpuscnla, 414 ; development of the
endosperm of Coniferse not always dependent on the contact of pollen
of the same species, 414, 415 ; second penetration of the pollen-tube
towards the embryo-sac, 415 — 421 ; development of free spherical ceils
in the ends of the pollen-tubes which reach or enter the corpusculum,
416; penetration of the pollen-tube into the corpusculum in Pinus
sylvestris, 417, 418 ; in Pinus Abies, L. {Abies excelsa), 418, 419 ; in
Pinus Larix, 419, 420 ; relation of the pollen-tube to the corpuscu-
lum, 421 ; development of the embryo, 421 — 432 ; evolution of the
impregnated germinal vesicle, 421, 422 ; Schacht ou this subject, and
Geleznoff on the formation of the embryo in Larix, 422, note ; rela-
tion of the pollen-tube to the endosperm in Taxus baccata, 422 ; de-
velopment of impregnated germinal vesicle iu that species, 423 ; im-

TABLE OF CONTENTS. XV11

PAGE

pregnation of Thuja orientalis, Juniperus communis, and /. Sabina,
424 — 426 ; evolution of the impregnated germinal-vesicle in Conifer*
generally, 426, 427; production and growth of the pro-embryo, 427
— 430; non-ramification of pollen-tubes in Abietineae, 430; several cor-
puscula impregnated in Taxus by the expanded end of one pollen-tube,
430 ; development of the pro-embryo in Taxus, 430 ; Hartig's obser-
vations on this subject, 430, note ; production of the pro-embryo in
Juniperus and Thuja, 431, 432 ; development of the embryo of Coni-
ferae, 432. Historical review : — 432.

CHAPTER XVI.

KEVIEW 434

Comparison of the development of mosses and liverworts with that of
ferns, Equisetacese, Rhizocarpeae, and Lycopodiaceae, 434 — 438;
alternation of generations in mosses and ferns, 434, 435 ; homologies
of ferns and mosses, 435 ; comparison with liverworts, 435 ; condi-
tions of life in mosses, compared with vascular cryptogams, 435, 436 ;
occurrence of thickenings of the cell-walls of sporiferous generations
of mosses and ferns, 436 ; want of natural foundation for the separa-
tion of mosses and liverworts into only two groups, 436, 437 ; their
division into four groups, 437 ; formation of the embryo of Coniferae
intermediate between that of the Phaenogams and higher Cryptogams,
438, 439 ; general considerations, 439 — 441.

Note on the cell-multiplication of the apex of the stem of the leafy

Jungermanniae 442

Explanation of the figures 443

Index 493

ON THE

GERMINATION,
DEVELOPMENT, AND FRUCTIFICATION

OF THE

HIGHER CRYPTOGAMIA.

CHAPTER I.

ANTHOCEROS LiEVIS AND PUNCTATUS.

The young germ-plants as well as the adventitious
shoots of Anthoceros form linear flat masses of cellular
tissue, the breadth of which continually increases from
back to front (PI. I, fig. 1). In the middle of the fore
edge a shoot is formed, on both sides of which, in the
angles between it and the adjoining parts of the fore edge,
new masses of cells are rapidly protruded. These con-
stitute, in the first instance, a vigorous median shoot,
on the right and left of which, shoots of a more delicate
nature are formed almost contemporaneously, which latter
in the progress of growth unite on either side with
the median shoot (PL I, fig. 7). The new shoots formed
by the amalgamation of these actively growing cellular
masses unite themselves on either side to the primary
shoot, which now constitutes the middle lobe of the fore
edge. By the rapid elongation of the new shoots, the
primary one increases in breadth, and its original semicir-
cular outline (PI. I, fig. 7) assumes that of the segment
of a circle (2 *). In the two indentations of the fore
edge of each of the new shoots the same process is re-
peated, and henceforth the regular ramification of the
plant goes on in like manner. At the bottom of the

1

2 HOFMEISTER, ON

two indentations exhibited by the fore edge of each
shoot (which indentations arise from the amalgamation
of three growing masses of cells, viz., a median shoot
and two side shoots) three cellular protuberances origi-
nate, first a median one, and then two side ones. They
grow into one another nearly up to their fore edge, and
unite on either side with the median lobe of the fore
edge of the next older shoot. By further elongation
they become new shoots, producing an increase in the
breadth of the median lobe. The ramification of the
plant is therefore irregularly dichotomous, depending
upon the continual formation of side shoots on either
side of a median shoot, which latter is limited in its
longitudinal growth — a mode of ramification which, in
the case of phsenogamous plants, has . been called by
Schimper "Dichassium." As the new shoots, lying in
one plane, diverge from one another at angles exceeding
90°, a succession of three generations of shoots suffices
to render the outline of the entire plant circular. The
habit of the plant depends, for the most part, upon the
extent to which the three component parts of each new
shoot amalgamate longitudinally inter se and with the
median lobe of the fore edge of the next older shoot.
Where the elongation of the lower part of the new shoots
begins at a late period, there the extent of the amalga-
mated growth is very considerable. This is the case
with specimens of Anthoceros Icevis growing in sunny
open fields. Here, in consequence of the perishing of
the oldest shoots, those namely which originate directly
from the spore, the plant usually has the appearance of
an exactly circular or slightly lobed expansion of dark
green, succulent cellular tissue. The extent of amalga-
mation of the shoots is much smaller in Anthoceros
jjunctatus, and still less in plants of Anthoceros Items
which have grown in moist shady places or in higher
temperature (as, for instance, in pots which have been
long under glass). The ramification of Anthoceros is
similar to that of the Riccieae, the Marchantieae, and
several leafless Jungermannise, as, for instance, Pellia.
In Anthoceros, however, the regularity of the ramification

THE HIGHER CRYPTOGAMIA. 3

is much interrupted by the fact that individual marginal
cells, and in Antltoceros punctdtus even the surface cells,
become transformed into adventitious shoots. The circum-
stances under which the plant grows have a decided in-
fluence upon the number of the adventitious shoots which
come to perfection ; and these circumstances also determine
whether the growth of such shoots shall terminate at an
early period, or whether, like the mother- shoots, they shall
continue to ramify and develope themselves. The latter is
always the rule in Antltoceros jpunctatus. It contributes
much more to the crisped, distorted aspect of the plants of
this species, than the perishing of the upper coverings of
the air-cavities which are enclosed in their tissue. In
Antltoceros lavis, ramification only takes place when the
plant grows in a very moist atmosphere and in deep shade.
Then A. lavis ramifies to as great an extent as the other
species, from which, however, it is decidedly distinguishable
by the entire absence of air-cavities in its tissue.

The flat stem of Anthoceros grows and elongates itself
by continual division of the cells of its fore edge. These
cells have the form of a three-sided prism, with one side
(that, viz., which forms the fore edge) convex. These cells
divide repeatedly by septa, which are inclined at angles of
about 45° alternately towards the upper and under surfaces
of the flat stem. In the cell constituting the fore edge
(viz., the cell of the first degree), the division is repeated
until the full number of cells belonging to the segment
(which segment is limited in its longitudinal growth) is
reached. This cell-multiplication terminates at a later
period in the median line of the segment than it does at
the sides. Hence it follows, that the shape assumed by
each of the three lobes of the fore edge of a shoot is that
of the segment of a circle. The cells of the second degree,
which are distinct from the three-sided prismatic cells of
the fore edge, have the form of procumbent prisms with
a rhombic base. Each newly formed cell of the second
degree divides immediately by a septum parallel to the free
outer surface. This division is followed by that of the
inner and outer daughter-cells, which takes place by means
of a septum parallel to the neighbouring cell, and at right

4 HOFMEISTJ5R, ON

angles to the free outer surface of the stem (PI. I, figs. 3,
4). The outer one of the cells thus formed continues to
divide by septa parallel to the free outer surface, until the
cells have reached the number of Avhich the shoot is des-
tined to consist in the direction of its thickness. This
number (about thirteen) is greatest in the median line
of the shoot, and diminishes to one at the sides. The
arrangement of the cells of a section of the end of a
growing shoot, taken through the median line at right
angles to the surface, is what is called scalariforni;
the cells of each longitudinal moiety of the shoot are ar-
ranged in rows parallel to one another bearing upwards
from the lonoitudinal axis. Each of the cell-masses which
unite to form a shoot consists in its earliest stage of a single
cell, situated normally at the bottom of the indentation of
the fore edge of an older shoot (PI. I, fig. 7), but, when des-
tined to form an adventitious shoot, placed at the edge or on
the surface of such older shoot. The primary division of
this cell, which takes place by a septum inclined to the
horizon, is followed immediately by the division of the
cells of the first and second degree, by means of a longitu-
dinal septum perpendicular to the surface of the stem. As
the young shoot increases in length, the number of its cells,
reckoned in the direction of its breadth, increases largely
and continually, the cells of its fore edge dividing in like
manner by longitudinal septa. Thus it happens that, as
long as the shoot grows, its fore edge becomes continually
wider. The arrangement of the cells seen from the sur-
face is flabelliform, in rows which radiate from the base of
the shoot to the arcuate fore edge. In each of the cells
which constitute the permanent upper and under surface of
the shoot, four cells are produced by duplicate cell-divi-
sions, which four cells lie in one plane. It follows that, in
full-grown shoots, these superficial shells are four times
smaller than the internal cells. A suppression of the final
septum not unfrequcntly occurs in individual cells of the
inner parenchyma. Some of the latter are often found
which are twice the size of the adjoining cells.

The growing cells of the fore edge of young shoots con-
tain a thick coating of a mucilaginous fluid rendered tur-

THK HIGHER CIIYPTOGAMIA. 5

bid by numerous granules, and in this fluid is a"spherical
or slightly flattened nucleus formed of a less highly
refractive substance (PL I, fig. 3). Appearances are not
wanting which point to a uniformity in the process of the
cell-multiplication with that which usually obtains in the
more highly organized plants. The nuclei of the cells of
the first and second degree appear sometimes to be under-
going a manifest process of dissolution. Individual cells of
the first or second degree are sometimes devoid of nuclei
(PL I, fig. 3 *). Not unfrequently two nuclei, not separated
by any septum, occur in one and the same cell. The; wall
between the cell of the first degree and the youngest cell of
the second degree is always of the greatest delicacy, so as
to leave no doubt that it has only just been produced.
From these facts it necessarily follows that the vegetative
cell-multiplication in Anthoceros (as in nucleate cells gene-
rally) commences by the dissolution of the primary nucleus
of the cell, which is quickly followed by .the formation of
two secondary nuclei. Between the two new nuclei a
eptum is then formed, which extends through the entire
cavity of the cell.

In the youngest cell of the second degree, sometimes even
in a cell of the first degree, there is produced near the surface
of the nucleus a colouring matter consisting of numerous,
immeasurably small, coloured particles. The particles are
of a pale bluish-green colour in the youngest cells ; in the
next older cells they tinge the immediate neighbourhood of
the nucleus (that is to say, the mass of protoplasm which
surrounds it, and from which filaments radiate through the
cell-cavity, PL I, fig. 3) with a bluish verdigris colour. In
rather older cells the colouring matter suddenly seems to be
enclosed in a well-defined vesicular body surrounding the
nucleus (PL I, fig. 6) ; the somewhat thick, membranous
peripheral layer of this body is of an intense emerald green.
The less highly refractive substance of the interior of this
body is of a much paler colour. At a later period nume-
rous very small starch-granules are usually formed in the
interior of the chlorophyll-bodies, and, for the most part,
inside the nucleus which they surround. No other changes

* Sec the lower cell adjoining the apical cell; a cell of the fourth degree.

S

6 HOFMEISTER, ON

of importance occur in the chlorophyll-bodies during the
life of the cell. Anthoceros alone, therefore, amongst all
known plants, exhibits the phenomenon of a single very
large chlorophyll-body in each cell.* The form of it in
Anthoceros Icevis is (in most of the cells) globular or ellip-
soidal; in the very elongated cells of older shoots it is
flattened and spindle-shaped, and then often much drawn
out at the points ; in the epidermal cells it is much flat-
tened, and, when seen from above, often irregularly stellate.
The normal form of the chlorophyll-bodies in Anthoceros
punctatus is similar. The chlorophyll-bodies of both species
are always parietal in the older cells, closely attached to the
mucilaginous layer clothing the inner surface of the cell,
i. e., the primordial utricle. By treatment with a weak
alkaline solution, the primordial utricle shrivels up. It
then appears in the form of a delicate sac, to the inner wall
of which the chlorophyll-body is attached (PI. I, fig. 10).
In cells which already possess a fully developed chlorophyll -
body, the duplication of the latter precedes the division
which takes place by the formation of a septum. In cells
on the under or upper surface, in which division is about to
take place, tw^o separate chlorophyll-bodies are often found,
each of which encloses a (secondary) nucleus (PL I, fig. 6).
In the chlorophyll-bodies of cells which are about to divide,
and which bodies occupy about two thirds of the cavity of
the cell, the included primary nucleus of the cell always
becomes less distinct, and eventually disappears altogether.
In the chlorophyll-bodies of other neighbouring cells may
be seen two indisputably newly formed nuclei. The chlo-
rophyll-bodies of other cells again exhibit a dark line in the
equator of the ellipsoidal chlorophyll-body (PI. I, fig. 14 ''),
the dark line being the side view of the dense assemblage
of immeasurably small coloured particles lying in the equa-
torial plane. No intermediate stages between this condition
and the perfect division of the chlorophyll-body into two
parts has been observed ; the one seems to follow imme-

* In the ' Vergleichende Untersuchungen,' p. 3, I called this body a
chhvophjW-vesicle — a name which H. v. Mohl has rightly objected to as inaccu-
rate, inasmuch as, when the chlorophyll-body has swollen and become partly
dissolved by the absorption of water, no trace of a surrounding membrane is
visible.— <Bot, Zeitung,' 1855, p. 107.

THE HIGHER CRYPTOGAMIA. 7

diately upon the other. These processes can be seen in the
cells of the wall of the lower part of the young fruit whose
cell-multiplication is in progress, and still more clearly in
the epidermal cells of young shoots. It is true that in the
cells of the fruit the chlorophyll-bodies are manifestly smaller
than in those of the epidermis. For this reason, however,
during the process of cell -multiplication which is con-
stantly going on from above downwards, no doubt can exist
as to the mode of succession and the signification of the
different states observed. The cells of the upper part of the
young fruit contain, without exception, two chlorophyll-
bodies. It would seem that here an ultimate division of
the cells commences, but is not perfected. In the inner
tissue of the stem the appearance of two chlorophyll-bodies
in one cell is unusual. I once saw between two such chlo-
rophyll-bodies a free nucleus ; it was united to both the
chlorophyll-bodies by a thread-like filament of granular
mucilage (PI. I, fig. 9).

The position of the organs of fructification of Anthoceros
is not confined to any definite points of the flat stem.
Both in Anthoceros lavis and in A. punctatus, groups of
archegonia and antheridia are scattered about, apparently
without regularity ; in some instances occurring in great
numbers upon one shoot, in others being very sparingly
distributed. The first appearance of antheridia consists in
the separation from the underlying tissue of a circular
group of about sixteen cells of the upper layer of a very
young shoot. Hence arises a small lenticular cavity in the
cellular tissue, which is filled with a watery fluid, and only
covered by a single layer of cells * (PI. Ill, fig. 16). Its
basal cells divide by vertical, longitudinal, and transverse
septa. Certain of the smaller cells which thus originate
(six in number at the utmost in A. lavis, but amounting to
twenty in A. punctatits) grow into short papillae, which pro-
trude into the intercellular cavity (PL III, fig. 16). The
dome-shaped portion, which protrudes considerably into the
air-cavity, becomes separated by a septum from the primary

* The large cavities in the interior of the cellular tissue of A. punctatus are
also formed by the separation of cells originally in close cohesion. These
usually die-shaped cavities contain at first a watery fluid, and afterwards air.

8 HOFMEISTER, ON

cell-cavity. In the hemispherical cell which is thus pro-
duced there commences, either immediately (Plate III,
figs. 10, 17) or after the occurrence of one or two divisions
of the same cell by means of horizontal septa, a series of
repeated divisions of the apical cell, by means of septa in-
clined in opposite directions. The cells of the second
order which are thus formed are bisected by the growth of
radial longitudinal septa (PI. Ill, fig. 18). There is thus
produced a short clavate mass of cellular tissue, composed
of four parallel longitudinal rows of cells. One of the cells
of the double pair of cells adjoining its apex divides by a
septum which, lying parallel to the longitudinal axis of the
organ, forms with the side walls of the mother-cell an
angle of 45°. Thus arises an inner cell which is sur-
rounded on all sides by a simple cellular layer. The inner
cell expands at the expense of the surrounding cells, the
latter becoming tabular and flattened. These cells hence-
forth multiply only by divisions produced by septa perpen-
dicular to the free outer walls. It is probable that the
number of the cells of the cortical tissue of the antheridia
increases, but such tissue always consists of a single layer
of cells. The inner cell, on the contrary, becomes converted,
by means of a series of continued bisections, into a multi-
cellular body, the cells of which become smaller in pro-
portion as their number increases (PI. Ill, figs. 19, 20).
In its latest stage of development, this cellular body is a
spheroidal mass of very small, almost tabular cells (PI. Ill,
fig. 21). Each of them contains a lenticular vesicle which
almost fills the cell. The walls of the cells decay as the
antheridia approach maturity. In the mean' time, in each
of the vesicles, a delicate helicoid filament of from two to
three and a half turns, and composed of a substance which
is coloured yellowish by iodine (PI. Ill, fig. 22), forms
itself into an antherozoicl. At this period the cellular layer
which covers the cavities in the cellular tissue of the frond,
and which cavities are almost filled with antheridia, bursts
irregularly. It often happens that in the mean time the
chlorophyll-bodies have assumed a reddish-yellow colour.
The same colour appears regularly and with increased in-
tensity, at the approach of maturity, in the colouring par-

THE HIGHER CRYPTOGAMTA. 9

tides of the cells of the covering layer of the antheridia, of
which several, to the amount of eight, are here found in
one cell. The antheridia, when fully ripe, open at the
apex, the cells of the covering layer parting asunder. The
contents, that is to say the lenticular vesicles before men-
tioned, emerge under water by degrees, and become
distributed in the surrounding fluid. The vesicles begin
to rotate slowly, during which the enclosed antherozoid
becomes free, apparently by the gradual dissolution of the
wall of the vesicle. It moves about slowly in the water,
rotating slowly round the axis of its spiral.

The formation of the archegonia of Anthoceros differs
essentially from that of all other Hepatic. A single string
of cells, situated on the upper side of a young shoot, and
directed obliquely backwards and inwards, becomes filled
with granular mucilage. The cells of this row are arranged
in a straight line one above another, and form part of a
group of cells produced by the multiplication of an upper
cell of the second degree. There is no formation of chloro-
phyll-bodies in these cells (PI. I, fig. 4). The lowest of
the cells of this row swells up during the time that the
cells of the stem are increasing in number in the direction
of its thickness, and, consequently, before the number of the
cells lying between such lowest cell and the upper surface
of the stem has reached its limit (PI. I, fig. 4, a). In
the basal cell a free daughter-cell is formed, which, in-
creasing rapidly in size, soon fills up the greater part of
the mother-cell (PI. 1, fig. 16). The transverse septa
which divide the rest of the cells of the row from one
another are then absorbed. Thus there originates a narrow
open passage, filled with mucilaginous fluid, which leads
into the interior of the tissue of the stem, and into the
basal cell of the archegoniutn, which is now open above
(PI. I, fig. 17). Seen from above, this passage is a hexagonal
opening, bounded by six cells of the epidermis, and becoming
narrowed inwardly to a cylindrical canal (PI. I, fig. 18 h).
By this means the spermatozoa, after their escape from the
antheridium, are enabled to reach the immediate neio-h-
bourhpod of the oval daughter-cell of the basal cell of the
archegonium.

10 HOFMEISTER, ON

So far all the archegonia comport themselves alike. In
many, however, the further development now ceases. The
daughter-cell which originated in the basal cell disappears.
Frequently the walls of the passage leading from the basal
cell outwards assume a brown colour. In other arche-
gonia, which in all probability have been impregnated by
the entrance of the spermatozoa, the daughter-cell, as well
as its nucleus, increases manifestly in size ; numerous large
granules appear in the fluid in its interior (PL I, fig. 17).
The oval cell soon divides by an oblique septum (PL I,
Jig. IS), upon which another septum, inclined in a contrary
direction, is shortly afterwards seen (PL I, fig. 20). In
the same manner, the terminal cell divides two or three
times by septa inclined in contrary directions (PL I, fig. 19).
The body, which at this period consists of a few large
cells, can now be easily isolated. After some time a division
of the apical cell takes place by means of a septum inclined
to the ideal longitudinal axis of the organ at the same angle
as the previously formed septa, but diverging from them at
an angle of 90°, and cutting the under edges of the apical
cell. The next septum which is formed stands opposite to
this, is inclined in a contrary direction, and forms also a
right angle with the two older septa of the cell. The ter-
minal cell of the obtusely conical body, which now plainly
constitutes the fruit-rudiment, increases by the production
of a series of septa which collectively have the same inch-
nation to the longitudinal axis of the young fruit, but which
point in four different directions, and not in two only, as
heretofore. The divisions succeed one another in such a
manner that the development of a septum turned towards
the south is followed by that of another turned towards the
north ; a septum towards the east is followed by one
towards the west, and so on.* The form of the cell of the
first degree resembles that of a three-sided prism with one
of its lone; sides turned downwards. The cells of the second
degree have partly the form of a parallelopiped, in so far as
they originate from the division of the apical cell by

* Tn the ' Vergleichende TJntersuchungen,' an erroneous statement has crept
in by a slip of the pen. The series of cell-divisions is erroneously stated to run
round the circumference of the apical cell in the course of aright-handed spinal.

THE HIGHER CRYPTOGAMIA. 11

a septum cutting one of its sides, and parallel to one of
its other sides ; and partly the form of a three-sided prism,
so far as they originate from the division of the apical cell
by a septum parallel to one of its short side-walls. Seen
from above, the apical cell has an oblong form (PL I, fig. 25);
in a longitudinal section, it is triangular if the section is per-
pendicular to the long side-walls (PI. I, figs. 21 "' c' 23 ''),
quadrangular, on the other hand, if the section is at right
angles to the shorter side-walls (PI. 1, figs. 21 * 23 ").
Each cell of the second degree divides, soon after its pro-
duction, into an inner and an outer cell, by means of a
septum parallel to the chord of the arc of the free outer
surface. Each of the latter cells is divided by a longitu-
dinal septum radiating from the longitudinal axis of the
fruit ; those cells adjoining to the side faces of the apical
cell being divided at an earlier period, and more repeatedly,
than those adjoining the terminal faces (PI. I, fig. 23).
These divisions take place in such a manner that the cell
is divided into two portions of unequal size, of which the
larger portion immediately divides again by a septum
parallel to the septum last formed. Further longitudinal
divisions take place (especially in the side cells of the
mass of cells which is formed by the multiplication of a
single cell of the second degree), in such a manner that,
measured in a tangential direction, their number appears
to be represented by the odd numbers, 3, 5, 7, &c.
(PL I, fig. 25). The division of those cells of the outer
surface of the fruit which immediately adjoin the apical
cell (which division takes place by a radial longitudinal
septum) is shortly followed by the formation of a trans-
verse septum, also perpendicular to the free outer surface,
but at right angles to the septum just mentioned. In
the cells which originate from the smaller cells of the
second degeee, the formation of the transverse septum
often precedes that of the longitudinal one (PL I, fig. 25).

In the rudimentary fruit of Anthoceros, as in other
growing organs, one step in the regular series of cell-
divisions is often anticipated. It sometimes happens that
a division takes place before the occurrence of another divi-
sion which usually follows it, and yet the final arrangement

12 HOFMEISTER, ON

of the entire mass of cells is not thereby materially affected.
The enlargement which takes place in a direction radial
to the axis of the fruit, and the cell-multiplication in the
direction of the sides of the paraboloid which constitutes
the apex of the rudimentary fruit, are somewhat more
extensive in the cells derived from the wider cells of the
second degree than in those derived from the narrower
ones. The outline, as seen from above, of the mass of
cells produced by the multiplication of each rectangular
combination of four cells of the second degree, which out-
line is at first elliptical, becomes consequently soon trans-
formed into a circle.

The innermost of the cells into which each cell of the
second degree divides is separated by longitudinal septa
into two halves. Immediately under the apex, the fruit-
rudiment consists of four axial longitudinal rows of cells,
which are covered by an almost entirely simple layer of
peripheral cells (PI. I, fig. 24). The fruit-rudiment in-
creases in thickness and circumference by the growth of
tangential longitudinal septa in the peripheral cells, which
growth is always repeated in the outermost of the new cells,
and alternates with the formation in the same cells of radial
longitudinal septa, The cells of the base of the very young
fruit-rudiment expand considerably in breadth, and thus
lay the foundation of the flattened spheroidal enlargement
by means of which the fruit is buried in the cellular tissue
of the stem (PI. I, figs. 21* 2.2). At the period of the
middle age of the fruit, the cells of this swelling not only
attach themselves very firmly to the neighbouring cells of
the stem, but force themselves inwards between the latter
cells to some depth, becoming transformed into cylindrical*
crooked papulae, comporting themselves like short radicular
hairs (PI. II, fig. 5).

The cells of the stem which adjoin the a^chegonium
multiply actively in all three directions of space during the
development of the fruit-rudiment, By this means the
surrounding tissue keeps pace, for a considerable time, with
the increase in size of the fruit-rudiment (PL I, fig. 19 ; PL
II, fig. 1) ; afterwards it usually so far outgrows the latter,
that a wide hollow space, filled with tough gelatinous

THE HIGHER CRYPTOGAM I A. 13

matter, is formed above the young fruit, into which indi-
vidual cells of the adjoining tissue protrude in the form of
jointed hairs (PI. II, fig. 2). A wart-like elevation of the
upper side of the flat stem denotes the spot at which a
fruit-rudiment lies concealed within. Owing apparently to
the position of the archegonium (i. e., the young fruit), this
excrescence is always oblique to the fore edge of the shoot.
Eventually the growth of the fruit exceeds that of its
covering. One of the causes of this growth is an increase
in. number (commencing at an early period, and continuing
until the bursting of the fruit) of those cells of its lower
portion which lie immediately underneath the basal enlarge-
ment ; or, in other words, a continually repeated division
of all the cells of one of the lower zones of cells. Another
cause of the growth of the fruit is an expansion of its cells
commencing at the apex of the fruit at the period when
the apical cell ceases to multiply, and extending slowly to
the base (PI. II, fig. 5). The fruit breaks through the
arcuate lid of the surrounding cavity, and carries the
decaying tissue of the lid upwards, attached to the gelati-
nous mass which is accumulated above the apex of the
fruit, and which is traversed by the jointed hairs now
broken up into their individual cells ; it (the fruit) then
appears above the surface of the stem, apparently sur-
rounded by a sheath. The dome-shaped mass of gelatine,
covered with a brownish layer of cells, is the so-called
Calyptra of the earlier observers (PI. II, figs. 4, 5*). The
differentiation of the parts of the internal tissue of the
fruit begins shortly before the latter breaks through its
covering, and proceeds from above downwards. Certain
cells, forming an axile cylindrical string of from twelve to
sixteen rows of cells, one above another (each now showing
four cells in transverse section), cease to form horizontal
septa, whilst in all the other cells at least one more such
division takes place (PL II, fig. 5). This string of cells
is the future columella. The layer of cells immediately
surrounding it is that out of which the spores and elaters
are developed, which extend from the columella to the
Avail of the fruit. In this layer the multiplication of the
cells by division by horizontal septa is twice as active as

14 HOFMJEISTER, ON

in other parts of the fruit. Measured vertically, one cell
of the columella, or two of the wall of the fruit, are equal
to at least four of the cells of the latter layer (PL III, fig. 1).
The wall of the fruit is thinnest in its upper part. It con-
sists there of only four layers of cells, whilst towards the
base there are five such layers (PL III, fig. 1), being the
result of the division of the cells of the second layer (reckon-
ing from without inwards) by longitudinal septa parallel
to the longitudinal axis of the fruit.

Those cells of the layer surrounding the columella which
are destined to be the mother-cells of spores become
detached from the neighbouring cells, and assume a spheri-
cal form. Their contents consist of finely granular proto-
plasm, and a large central transparent nucleus with a large
nucleolus (PL III, figs. 1, 3). Those destined to form
elaters remain less developed. Their nucleus disappears ;
in its place are seen two new nuclei, between which a
septum is produced, dividing the cell into two daughter-
cells (PL III, fig. 1 l). The same process recurs in one,
sometimes in both, of the newly formed cells ; so that the
fully grown elater consists of a row of three or four cells.

The perfecting of the spore-mother-cells proceeds slowly
from the upper to the lower part of the fruit. A well-
made longitudinal section of a half-ripe fruit exhibits a
graduated series of all the different states, from the first
separation from the neighbouring cells up to the formation
of the spores. The spore-mother-cell increases rapidly in
size after becoming detached from the neighbouring tissue.
The protoplasm in its interior divides into strings, radiating
from the nucleus, and into a thin parietal layer (PL III,
fig. 4). Shortly afterwards an accumulation of mucilagi-
nous plasma is formed close to the primary nucleus which
occupies the middle point of the cell. This plasma, in
Anthoceros lavis, is usually coloured green by the particles
dispersed in it ; in A. pimctatus it is colourless. This
accumulation divides itself into two halves, each of which
clothes one of the poles of the globular nucleus (PL III, figs.
5, 5''). In slightly older cells, twTo newly formed second-
ary nuclei are found near the primary nucleus, surrounded
by a halo of finely granular protoplasm, from which strings

THE HIGHER CRYPTOGAMIA. 15

of protoplasm radiate to the inner wall of the cell (PI. Ill,
fig. 6). The new nuclei, in Anthoceros lavis, usually con-
sist of a greenish substance ; in A.punciatus, of a colourless
substance, containing coarser particles. They doubtless
originate from the fact, that each of the accumulations of
protoplasm which clothe either pole of the primary nucleus,
has become rolled into a ball, and distinctly defined. Hie
layer of protoplasm which surrounds each of the newly
formed nuclei, often contains so many granules, that the
outlines of the latter are at first completely concealed, and
only become visible long after their first production. The
contrary, however, is frequently the case in both species.
The secondary nuclei are often without any solid substances
in their interior. Sometimes they contain a single large
nucleolus ; sometimes a larger number of granules, which,
becoming blue with iodine, indicate the existence of starch.
Late in the autumn, after the occurrence of the first frosts,
each of the secondarv nuclei is found, in manv of the fruits,
surrounded by a thin-walled, rather larger cell (PL III,
fig. 15). Fruits of this kind decay - without further de-
velopment : their state is one of disease.

In more fully developed mother-cells lying nearer to the
apex of the fruit, the outlines of the secondary nuclei are hazy
and less defined. Ultimately two masses of granular proto-
plasm are found occupying their place, the limits of which
arc confluent with the surrounding layer of protoplasm
(PL III, figs. 7, 8). In the mother-cells immediately above,
each of these masses is divided into two sharply defined
globular balls, i. e., into two tertiary nuclei. Their position
at first is ordinarily decussate (PL III, fig. 9) ; at a later
period, they usually group themselves in a manner answer-
ing to the four corners of a tetrahedron. They are bound
together by thick strings of protoplasm ; thinner strings
of more finely granular, almost transparent protoplasm
proceed in greater or less numbers from each nucleus to
the inner wall of the cells (PL III, fig. 10). Up to this
point the primary nucleus of the cell has become continually
more transparent and paler; now, it and its nucleolus
have disappeared. Immediately thereupon the mother-cell
divides into four daughter-cells ; the special-mother- cells,

16 HOFMEISTER, ON

by means of six triangular septa, passing between eaeli two
nuclei, and cutting each other in the middle point of the
cell. The wall of the mother-cell increases manifestly in
thickness from the time of the appearance of the secondary
nuclei until the formation of the septa, In Antltoceros Icevis,
it remains smooth ; in Anthoceros punctatus it is furnished
with numerous dots {Tiipfelri) • (PI. Ill, fig. 23). The
inner layers of the thickened wall are very sensitive to the
action of water, especially in Anthoceros lavis ; they swell
up rapidly, and to a great extent, contracting the cavity of
the cell, and compressing its contents into a small space,
causing great difficulties to the observer. The affinity of
the swelling layers for water is so remarkable, that the
swelling takes place even in saturated saline solutions.
Alcohol is the only medium in which it fails to occur ; it
is very much diminished in diluted alcohol. If spore-
mother-cells, in which the four tertiary nuclei are fully
formed, are placed in diluted alcohol, the cell-contents first
contract ; a slight swelling of the membrane of the cell
then begins, which increases in proportion as the alcohol
escapes by evaporation from the fluid. It is now plainly
seen that it is one of the middle layers' in particular of the
cell-wall which increases in size by absorption of water
(PI. Ill, fig. 11). The outermost layer of the membrane
passively follows the increase in size of the middle one, and
becomes expanded. If pure alcohol is added, water is
withdrawn from the swollen membranous layer ; the latter
diminishes in size ; the outer layer of the cell-wall there-
upon becomes wrinkled, inasmuch as its volume does not
diminish in the same proportion as that of the middle
layer, and its elasticity does not equal its power of ex-
pansion. H. v. Mold has shown that the formation of
the septa of the mother-cells progresses gradually from the
periphery to the centre; and he has figured a condition in
which this growth has taken place to so small an extent
that the yet imperfect septa have not interfered with the
strings of protoplasm uniting the four tertiary nuclei.* The
rapid swelling up of the walls of the mother-cells prevented
me for a long time from repeating this observation, which

* 'Linnrca,' 1S36; " Vermisclite Schriften," tab. iv, fig. 23.

THE HIGHER CRYPTOGAMIA. 17

is certainly of great importance with reference to cell-multi-
plication. However, since I made the experiment of using
alcohol in the observation, I found in every fruit which was
submitted to dissection spove-mother-cells (situated between
spore-mother-cells which were yet undivided and others
which were already completely divided into four daughter-
cells) the inner walls of which were traversed by the rudi-
ments of the future septa, in the form of ridges protruding
inwards (PL II, fig. 12). By adding water to such a
preparation, the imperfect septa are seen to be direct con-
tinuations of the innermost layer of the cell-wall, which
layer swells up but little in water (PI. Ill, fig. 13). The
swelling up of the inner layers of the membrane of the
mother-cells has a peculiar appearance in those mother-cells
in which very numerous strings of protoplasm pass from
the tertiary nuclei to the cell-wall.' The enlarging sub-
stance of the membrane does not force these strings in-
wards, but shapes them to itself and clings to them (PI.
Ill, fig. 15). The swollen substance of the membrane is
manifestly less firm than that of the strings of protoplasm.*
Nevertheless, the swollen layer of the wall exhibits sharp
broken edges when the cell is ruptured by pressure with
the covering-glass. It is only after prolonged soaking in
water that the substance of the swollen layers becomes dis-
integrated ; the middle layers first dissolve, and then the in-
nermost ones ; the outermost layer remains behind to the last.
After the walls of the special mother-cells have attained
a moderate thickness, there is formed in each one of them
a single spore, which, from the first moment of its membrane
becoming visible, occupies the entire cavity of the mother-
cell. In Anthoceros punctatus, the prominences attached to
the outer membrane of the spore exactly fill up the dots of
the wall of the mother-cell. Irregularities of spore forma-
tion occur in both species : occasionally two special-mother-

* It was probably the observation of similar cases which led Kiitzmg to the
erroneous notion that the prolongations of the exosporium were hardened,
thread-like prolongations of the protoplasm surrounding each of the nuclei.
('Philos. Bot.,' Lcipz., 1S51, p. 264-.) The error of this view is at once mani-
fest, from the fact that the exosporium of Anthoceros presents, at its first
appearance, an entirely smooth outer surface. Its protuberances originate at a
later period.

2

18 H0FME1STER, ON

cells and two spores only are formed in some of the mother-
cells, in which case the two spores are double the usual
size ; this is similar to what occasionally takes place in the
formation of the pollen of many phamogams. When the
upper four-fifth parts of the long cylindrical fruit have be-
come filled with ripe spores, the wall, which assumes a dark
brown colour as soon as it contains ripe spores, splits lon-
gitudinally into two halves, and the spores which have be-
come free by the absorption of the walls of the mother-cells
are dispersed. These spores are of a brownish-yellow
colour in Anthoceros lavis, and somewhat darker in Antho-
ceros punctatus.

Both species are also reproduced by buds. These are
formed in the interior of the tissue of the stem in the follow-
ing manner : — The contents of individual cells of that tissue,
after a slight contraction of the entire upper surface, become
clothed with a new membrane (PI. I, fig. 11), and the
new cell thus formed becomes transformed into a cellular
body by a series of divisions following the course of
those which occur in the cell-multiplication of young shoots
(PI. I, figs. 12, 17). This cellular body sometimes com-
mences its own independent development by the protrusion
of radicular hairs, even Avhilst fully enclosed in the cellular
tissue (PL I, fig. 13). The contents of the cells of very
young buds consist of colourless protoplasm ; the cells of
older buds are filled with numberless small starch- granules,
between which is seen a dark bluish-green colouring
matter, composed of extremely minute particles. The buds
are usually set free by the disintegration of the tissue sur-
rounding them, which takes place as the stem slowly
decays from back to front. If they remain very long en-
closed in the tissue of the stem, a discoloration of, the
parenchyma commences in their middle, which is followed
by the breaking up of the bud into its component cells, and
this latter process advancing gradually to the periplieiy
ultimately destroys the bud! The development of the
spores of Anthoceros is a process which has been the subject
of very many observations (Mohl. sup. ' Nageli Zeitschr.
f. Botanik,' II. 2; Schacht, 'Berl. Bot. Zeit.,S 1850, 24—
2C). The observers just cited agree with me as to the

THE HIGHER CRYPTOGAMIA. 19

facts observed in all essential points ; but there is a dif-
ference of opinion as to the interpretation of these facts.
Mohl assumes that the duplication of the secondary nuclei
takes place by gradual constriction ;* Nageli, that it occurs
by the growth of a septum bisecting the internal cavity of
the secondary nucleus of the first order, and by the subse-
quent differentiation of the two halves ; Schacht's notion
of the process approximates to that of Mohl, from which my
own explanation only differs in the mode of expression.

Figures of Anthoceros are to be found in Dillenius
(' Historia Muscorum/ torn, lxviii, figs. 1, 2), in Schmidel
('Icones pi.,' t. xix, A. lavis ; t. xlvii, A. punctatus), and
also in Heclwig {A. Itevis, theoria generat., ed. ii, t. xxix,
xxx). According to these figures, the characters of the
flowers appear to be principally grounded upon a " radi-
ating mode of growth, progressing in all directions from a
central point of attachment." The history of the develop-
ment of the fruit which is given by the above observers
does not extend further back than the appearance of the
fruit above the edge of its veil or covering. Nees v. Esen-
beck (' Naturgeschichte der Europ. Lebcrmoose,' B. iv,
s. 334, 1838) describes the rudiments of the fruit, whilst
enclosed in the substance of the stem, as archegonia {Stem-
pel). Bischoff, on the other hand, had already (1835)
rightly described the relation of the young fruit to the
tissue of the stem which covers and encloses it (' Nova
Acta Acad. C. Carol. Leop.', T. xvii, p. 2, s. 934), and has
figured it, (' Hanclb. der Botan. Terminol/ B. ii, t. lxvi,
fig. 2783.) He does not mention the archegonia. Schacht
has lately (' Berliner Bot. Zeit. Jahrg,' viii, 1850, N. 24—
26) published a contribution to the history of the develop-
ment of the fruit and spore of Anthoceros. My own obser-
vations, in the 'Vergleichende Untersuchungen,' were com-
pleted before the appearance of Schacht's paper. Schacht has
only once observed an archegonium (1. c. 459), unfortunately
an imperfect one, of which the essential parts were already
decayed. The arrangement of the cells of the stem adjoining
the base of the archegonium appeared to him to bear a great

* See Wagner's ' Handwoiterbuch der Physiologie,' 13d. iv, s. 215.

20 HOFMEISTER, ON THE HIGHER CRYPTOGAMIA.

resemblance to that occurring at the base of the rudimen-
tary fruit. This led him to the erroneous conclusion, that
the fruit was the product " of certain cells lying at the bot-
tom of a small, narrow, deep canal of the leaf!' The above
remarks show the inaccuracy of this view. The following
observations will exhibit the essential agreement in fruit -
formation existing between Anthoceros and the liverworts
and mosses generally.

CHAPTER IL

LEAFLESS JUNGERMANNIiE.

Prllia epip7i.y1la, Aneura pinguis and multijida, Mcfsr/eria

fur cat a.)

Amongst all the liverworts indigenous to Germany,
Pellia epiphylla lias the largest spores. They are oval,
surrounded by a delicate, finely granular outer mem-
brane ; in the ripe state, as they escape from the opening-
fruit, they arc multicellular. They usually consist of four
cells, arranged in a single row, two of which are disc-
shaped and two hemispherical (PL IV, fig. 1). Sometimes
one of the former is divided by a longitudinal septum, so
that the spore is 5-cellular (PL IV, fig. 2). The internal
cavity of the cell contains much chlorophyll ; the green of
which, appearing through the thin, pale-yellowish wall of
the capsule, imparts to the unopened fruit its dark colour.
The cell which constitutes one of the ends of the spore
contains a far smaller quantity of chlorophyll-granules than
the other cells. From it springs the first of the long root-
like papillae by which the plant is attached to its place of
support. The cell next to this divides by a longitudinal
septum a few hours after the spores have been sown
on moist earth, even if such division has not taken place
earlier ; the same process then follows in the neighbouring-
cell, and frequently also in the cell opposite to the radicular
cell. Each pair of cells of the middle region of the germi-
nating spore is doubled by longitudinal division, taking-
place principally in the direction of one of the transverse
diameters (of the spore). Some varieties occur throughout
the whole extent of the cell-multiplication caused by this
longitudinal division, which, however, have little influence
upon the ultimate form of the plant. The division begins in
the cells next to the rooting cell (PL IV, fig. 3), sometimes

22 HOFMEISTER, ON

only in one of these cells (PL IV, figs. 4, 5, 9), sometimes in
the cells next but one to the rooting cell (PI. 4, figs. 6, 7),
or even in one only of such cells. The germ-plant con-
sists now of the basal cell, which is protruding the first
radicular papilla ; of two sets of cells above the basal cell,
each consisting of from two to four cells adjoining one
another ; and of the apical cell, which is already not unfre-
quently divided by a longitudinal septum (PI. IV, figs. 9, 10).

The activity of cell-multiplication in the direction of the
breadth of the plant increases continually towards the apex.
Although it never occurs more than once in the cells next
to the basal cell, it is a rare occurrence when it only takes
place in one of the next higher cells, and it is a rule almost
without exception that it happens repeatedly in the fourth
pair of cells reckoned from the basal cell upwards (PL IV,
figs. 12, 14). Hence the plant assumes the form (more
and more distinctly marked as it advances in growth) of a
plate widening continually towards the fore edge. In its
earliest youth the base, notwithstanding the smaller number
of its cells, is as Avide or wider than the apex. The expan-
sion of the lower cells, which occurs at an 'early period,
keeps pace up to a certain point with the increase in
breadth of the upper cells. But, when a month old, the
outline of the young plant has already assumed the shape
of a spatula (PL IV, fig. 14).

The expansion of the cells adjoining the base of the
plant begins at the time of the protrusion by the basal cell
of the first rootlet ; this takes place contemporaneously
with the commencement of the multiplication of the cells
in the direction of the longitudinal axis, which latter
results only from the continual division of the apical cell,
or (as is more often the case) of the two adjoining apical
cells. Both cells divide contemporaneously by a very
oblique* longitudinal septum, upon which a similar septum,
inclined more obliquely, but in the opposite direction,
is soon imposed (PL IV, figs. 7, 8, 13). This division of
the terminal cells by septa alternately inclined in different
directions to the surfaces of the plant, is repeated con-
tinually, and with tolerable rapidity ; for instance, twice in

* The longitudinal axis of the spore being considered to be vertical.

THE HIGHER CRYPTOGAMIA. .23

three days in a plant kept moist upon the stage of the
microscope. If the number of the apical cells of the plant
increases in a lateral direction by the division of the exist-
ing cells, the like process immediately follows in all the
newly formed cells : in the entire row of apical cells
division takes place continually by septa inclined either to
the upper or the under surface of the plant. The newly
formed cells of the second order divide, very shortly after-
wards, by septa almost parallel to the surfaces of the plant
(PL IV, fig. 13). By this means the number of layers of
cells increases, and with it the thickness of the plant. This
increase is only slight at first ; it does not seem that the
process is repeated whilst the plant is quite young, or
that either longitudinal or transverse sections exhibit more
than four layers of cells. Very frequently those cells only
divide which are turned towards one (? the lower) surface ;
the plant then consists, in the direction of its thickness,
of three layers of cells (PI. IV, fig. 16). By this time
certain of the superficial cells of the plant are divided once
or twice by a septum perpendicular to the surface, which
cells consequently appear twice or three times as small
as those in the interior of the tissue (PI. IV, fig. 13). This
is afterwards the normal condition. By the penetration
of the first rootlets into the ground, the young plant
is set erect. It retains this position only a short time.
The expansion which immediately commences in the
the cells of its lower portion is not uniform ; the cells of one
surface expand far less in a longitudinal direction than
those of the other (PL IV, fig. 13) : hence it follows, that
the apex of the plant becomes more and more inclined to-
wards the less expanded side of the basal cell, i. e., .the
future under surface of the plant ; so that the direction of
the growth of the young Pellia is parallel to the surface of
the soil beneath it. Individual cells of the under side,
especially those lying in the median line, grow out into
long rootlets, which penetrate deeply into the ground.
The rootlets originate in the following manner : at a certain
point, usually, exactly in the middle of the outer surface of
one of these cells, the membrane grows out into a strongly
developed point, which shortly leads to the formation of a

24 HOFMEISTER, ON

long tube attached to the cell. The mode of origin of the
first main root does not differ essentially from that just
described ; the conical cell which emits the rootlet usually
(not always, see PI. IV, fig. 12) becomes transformed by
degrees into the main root.

In consequence of the commencement of the expansion
of the basal cell of the germ-plant, the outer membrane of
the spore (which, although it has become considerably ex-
panded and more delicate, has, nevertheless, up to this point,
still enclosed the germinating spore) is ruptured (PI. IV,
fig. 10). The debris of this membrane may be found, for
some time afterwards, attached to the apex of the young
plant (PL IV, fig. 13).

By this time, the cells nearest to the fore edge of the
young Pellia have begun to protrude short club-shaped
hairs (PI. IV, figs. 13, 14), which appear in increased
numbers as the growth of the plant progresses (PI. IV,
figs. 24, 27).

From six to eight weeks after the sowing of the spores,
the germ-plant has, partly by the multiplication and partly
by the expansion of its cells, attained a length of from ^ '"
to § '". It is now attached to the ground by a larger num-
ber of rootlets ; the fore edge, from repeated division of its
marginal cells, has become wider than the older parts. At
every repetition of a longitudinal division of the marginal
cells, the septa, which continue to be perpendicular to the
surfaces of the plant, appear to diverge laterally more and
more in the fore part of the plant. The consequence is, that
the arrangement of the cells (PL IV, fig. 15) is flabelliform .
The sides of the fore edge grow more rapidly than its middle,
partly on account of a more frequent division of the cells by
means of septa inclined alternately in different directions,
but principally on account of a more vigorous expansion of
the cells. The apex of the young plant appears indented,
at first slightly, afterwards more deeply (PL IV, fig. 15).
The cell which occupies the bottom of the indentation
begins all of a sudden to multiply itself actively. It divides
twice by a transverse septum perpendicular to the surfaces
of the plant. The foremost of the new cells divides by a
longitudinal septum into two, each of which is again divided

THE HIGHER CRYPT0GAM1A. 25

by a transverse septum. The body thus formed, of which
the ground plan exhibits five cells, now protrudes into the
indentation of the fore edge (PL IV, fig. 17). The further
multiplication of its cells in the superficial direction takes
place, in the following manner : a membrane, directed
obliquely outwards, is mounted upon each of the last-formed
transverse septa ; thereupon each of the inner ones of the
four newly formed cells of the fore edge divides by a trans-
verse septum at right angles to the longitudinal axis of the
shoot. In each of the outer cells there is formed, at the
same time, a longitudinal septum parallel to the last-formed
oblique septum. By this means the ground is laid for the
fan-shaped arrangement of the cells of the middle shoot.

All that is now necessary for the development of the cell-
arrangement of the half-developed (PL IV, fig. 23) as well
as of the perfect middle shoot, is the repetition of the
division by transverse septa of the two middle cells of the
fore edge — the repeated transverse division of the cells late-
rally adjoining the latter- — the commencement of a longitu-
dinal division in these cells after a repetition once or twice of
the transverse division, and lastly, — the frequent recurrence
of the same series of divisions in the lateral cells for the
time being of the fore edge of the shoot.

The growth of the middle shoot of the germ-plant is
limited, as is the case with all the divisions of the stem in
Pellia. The multiplication of its lateral cells is slight at the
base, increases to the middle, and increases rapidly from
thence to the apex. The form of the shoot is therefore
cither that of a short spatula, or semi-oval.

The cells which are situated in the axil formed by the
middle shoot and the lateral wing of the germ-plant begin
to multiply vigorously, according to a similar rule, as soon as
that shoot has attained to about a fifth part of its develop-
ment. The cell, which, when seen in profile or from above or
below, is oblong or trapezoid, appears, when viewed in the
direction of the surface of the plant, divided in the first in-
stance, by means of a transverse septum, into two cells, of
which the hinder cell is square, and the front cell trapezoid.
The latter divides by a longitudinal septum ; each of the
newly formed ones again by a transverse septum ; the outer

26 HOFMEISTER, ON

cells thus formed divide by laterally inclined longitudinal
septa, and so on, as in the case of the origin of the middle
shoot. The like process is repeated in the angles at both
sides of the new shoot, soon after the commencement of its
formation. A shoot originates in each angle, which unites
in growth with the median shoot, on the side which is
turned towards the latter. By this means a new shoot is
formed on each side of the middle segment of the fore edge
of the young plant (PI. IV, fig. 19), which new shoot, in
consequence of its being composed of three united shoots,
is tripartite at its fore edge. The flat cellular masses which
thus originate unite in growth firmly and intimately with
the middle shoot, by the edge which is turned towards the
latter. The new shoots, composed of these amalgamated
cellular bodies, protrude from the indentations of the
fore edge of the young plant, in consequence of the
commencement of longitudinal expansion in its basal
cells ; by their expansion, the middle lamellae which are
united _to them are drawn out laterally. Their form is
now a complete repetition of that of the germ-plant in
its earliest stage : the fore edge exhibits a short, spatula-
shaped median segment, and two lateral wing-shaped ones.
The subsequent ramification takes place in like manner.
There is one invariable rule for the entire development of
the plant, commencing from the formation of the middle
shoot of the germ-plant : the rule is, that each shoot has its
origin in the amalgamation of three shoots, which are formed
almost contemporaneously in one of the indentations of the
fore edge of an older shoot. Each new shoot, therefore,
exhibits at its first appearance two indentations of the fore
edge. According to the ordinary rule, new shoots are
formed only in those indentations which point out the
boundaries of the three amalgamated shoots. Hence arises
the furcate ramification of the plant (PI. IV, figs. 19 — 22).
The growth of each shoot is limited.*

* Bischoff considers that the first shoot of the germ-plant of Pellia is a prothal-
lium, distinct from the subsequent shoots. ('Handb. d. Terminologie,5 ii, 733 ;
'Botan. Zeitung,' 1853, 115.) As, however, the first shoot is not distinguish-
able in any essential particulars from the later ones, I agree with Gottsche
('Bot. Zeitung,' 3858, Anhang, 16) in thinking that there is no ground for this
distinction.

THE HIGHER CRYPTOGAMIA. 27

The multiplication of the cells of each shoot in the
direction of its longitudinal axis takes place exclusively in
the cells of the fore edge. In the young germ-plant they
divide, as has been shown above, by septa inclined to the
horizon alternately in different directions. The form of
the cell-multiplication in the fore edge of the growing-
shoots of older plants is essentially different. Here the
marginal cells divide by septa which are parallel to one
another, slightly convex on the inner side, and perpendi-
cular to the surfaces of the plant. This form of division
often occurs in young germ-plants of two months old
(PI. IV, fig. 24). The phenomenon which occurs so fre-
quently,— viz., the fact that in the earliest stages of develop-
ment the division by horizontal septa parallel to one an-
other* precedes that which in all subsequent stages is the
normal mode of cell-multiplication, viz., division of the
terminal cell by septa alternately inclined in different direc-
tions,— makes it probable that the latter form of cell divi-
sion is to be looked upon as a more perfect, higher form of
growth than the former. Still more remarkable is the
fact (which as yet stands alone), that in Pellia the simple,
apparently lower form of cell-multiplication follows, in
point of time, the more complex form which occurs in the
later periods of the life of the plant.

This phenomenon appears most distinctly in the first
spring-shoots of fruiting specimens. Here the cells of the
fore edge of the first, second, and third order exhibit,
during the growth of the shoot, large and manifest nuclei,
from which mucilaginous threads often pass to the walls of
the cells; they contain, besides, a slightly granular, yellowish
slime. In the older cells lying- behind the fore edge,
numerous small chlocophyll-granules make their appear-
ance ; the nuclei of these cells are less easily seen (PI. IV,
fig. 25). The cell of the first order — the terminal cell- — has
the form of a slice taken from the middle of a double convex
lens by two sections parallel to the small axis ; the cell of
the second order, at its first appearance, is shaped like a

* This occurs in the prothalHuin of mosses, in the suspensor of Selaginella,
in the greater number of phsenogans, and in the rudiments of the fruit of
many mosses.

28 IIOFMEISTER, ON

similar slice from a Meniscus. Through the division of these
cells by means of septa parallel to the surfaces of the plant,
the shoot increases in thickness. The first of these septa does
not coincide with the ideal axis of the shoot ; the two parts
into which it divides the cell are very unequal (PI. IV, fio-.
25). The two newly formed cells divide again several times
by horizontal septa ; the thickness of the plant, however,
never seems to go beyond eight layers of cells. From some of
the cells near the fore edge, hairs, shaped like a club, and
bent forwards, take their origin. The latter become bicellu-
lar, soon after their appearance, by the growth of a transverse
septum. The basal cell, when fully grown, usually con-
tains starch-granules ; the terminal one, a thin fluid muci-
lage. A membranous layer of tough gelatine encloses
the growing fore edge of these hairs. The cells which form
the permanent upper and under surface of Pellia ultimately
divide by a vertical, longitudinal, and transverse septum ;
so that each cell of the outer layer is four times as small as
one of the neighbouring inner cells. This division occurs
sometimes in the fourth youngest, sometimes even in the
seventh youngest group of cells produced by a cell of the
second order. As the growth of a shoot progresses, the
activity of the cell-multiplication in the direction of its
thickness diminishes continually from the base to the fore
edge, more slowly, however, in the median line than at the
sides. The free margin of each shoot of which the deve-
lopment is completed, is formed of a single layer of cells ; at
the base of the indentations of this margin are found pro-
tuberances of cellular tissue projecting downwards : these
are the young new shoots.

The shoots of barren plants growing in flowing water
exhibit conditions in the position and shape of their cells,
which can only be explained by looking upon them as forms
transitional between the first and the second form of cell-
multiplication (PI. IV, figs. 26, 27).

It is a remarkable circumstance that, in the earliest
spring-shoots of Pellia, the two sides, owing to the more
vigorous expansion of the cells of one of them, are always
unequally developed. One of the shoots which protrude
themselves from the indentations of the fore edge pushes

THE HIGHER CRYPTOGAMIA. 29

up apparently to the apex of the parent shoot through the
distortion of the outline of the latter, whilst the other
appears at some depth below, closely pressed to the side
(PL IV, figs. 20, 21). The former is always developed
more rapidly than the latter (PL IV, fig. 22), which often
fails altogether, often remains quiescent for months and
then suddenly begins to grow. Most of the disturbances of
the regular furcate ramification have their origin in the
circumstances just mentioned.

It is only in barren plants (where it often occurs) that
shoots are found on the upper side also of the flat stem.
In individual cells of the surface there commences a pro-
cess of cell-multiplication differing, so far as regards its
regular mode of progression, in no material respects from
that which obtains in the germination of spores (PI. IV,
tig. 28). A number of shoots of the above nature, similar
to germ-plants, only more fleshy, are often situated close
together: — in old joints of the stem I have counted as many
as thirty upon a single joint. The tufted mode of growth
of barren Pellige in flowing water may, perhaps, be owing
to these shoots.

On the upper side of the earliest spring-shoots of fertile
Pellia?, club-shaped cellular masses are protruded, consist-
ing of a short central string, usually of only two cells, sur-
rounded by a single layer of four cells, each lying at the
same elevation (PL IV, fig. 29) : these are the first rudi-
ments of the antheridia. The arrangement of the cells leads
to the conclusion that they have originated in the division
by means of septa inclined alternately in different directions,
of one of the cells of the upper surface. Each cell of the
second order is divided by a longitudinal septum ; two of
the cells thus formed, which are placed one above another,
and have almost the form of the quadrant of a cylinder, are
divided by a septum cutting the side-walls at an angle of
45°, into an inner three-sided and an outer four-sided
cell, of which the latter has an arched outer surface. This
determines the structure of the first rudiments of the
antheridium. By continual multiplication of the five cells
of its clavate end, the inner one of which divides in all
three directions, the four outer ones only in the direction

30 HOFMEISTER, ON

of the tangent, the antheridium assumes the form of a
mass of cellular tissue, supported upon a very short stalk,
consisting of four cells. Contemporaneously with the
first appearance of the young antheridium above the surface
of the joint of the stem, an annular wall of cellular tissue
is raised round the antheridium by means of repeated
division of the adjoining cells of the upper surface of the
frond (PL IV, fig. 29), which Avail, keeping pace in its
growth with that of the antheridium, surrounds it when
ripe, enclosing an open space above its apex.

The cells, sixteen to twenty-five in number, of the outer
cellular layer of the ripening antheridium are flattened and
tabular (PL IV, fig. 30). Their walls are covered with
rather large chlorophyll-bodies (starch-grains surrounded
by a very thin green layer), which, when the organ is fully
ripe, assume a dull yellow colour. The inner cells continue
to divide for a long period by alternate longitudinal and
transverse septa ; so that the antheridium, when nearly ripe,
consists of a globular mass of very small, four-sided, tabular
cells, surrounded by a single layer of large, flat cells, con-
taining chlorophyll. Each of the small tessellated cells con-
tains a lenticular vesicle, in which a spiral thread is formed,
consisting of transparent mucilaginous matter (PL IV, figs.
30 — 32). When the antheridium is fully ripe, the cells of
the covering layer separate from one another at the apex ;
the small cells, whose primary intimate adhesion has been
destroyed by the softening and swelling up of the cell-mem-
branes, escape through the crevices, mixed with mucilaginous
granules, in the form of a thick pultaceous mass ; when
brought under water, they disperse themselves in the fluid.
The spiral thread enclosed within them (the spermatozoid)
soon exhibits an active whirling motion, in consequence of
which it resembles a closely wound watch-spring (PL IV,
fig. 32 ■■ *•); it is still surrounded by the lenticular vesicle,
which, however, during the motion, can with difficulty be
seen. When the wall of the vesicle which envelopes the
spermatozoid bursts (which usually occurs after the vesicle
has been in the water for half an hour), the spermatozoid im-
mediately escapes through the fissure. It then forces its way
through the gelatinous, softened substance of the wall of the

THE HIGHER CRYPTOGAMIA. 31

(originally tabular) mother-cell. The turns of the spiral are
drawn out from one another, so that it assumes the form of
a screw. The spermatozoicl moves about with some rapidity
in the water, keeping up a continual revolution round its
own axis, and often dragging behind it the ruptured vesicle.
The hinder end of the spermatozoicl is drawn out into a very
long, fine point ; the opposite end is thickened, but hardly
perceptibly so. At this end I saw very clearly, in sperma-
tozoids whose motion had been arrested by a solution of
iodide of potash, two long, thin, lateral cilia, exactly like
those which Thuret discovered in the spermatozoa of Chara.
The observation of these cilia, which I could not succeed in
finding in any other liverwort, is a matter of some difficulty
even in Pellia with our present magnifying powers. The cilia,
and the thread-shaped ends of the spermatozoa, which some-
times adhere to other bodies, exhibit an active motion which
is winding and helicoid rather than pendulous. One end of
a spermatozoicl will often remain attached to the mucila-
ginous mass which escapes w7ith it from the ripe anthe-
ridium. The movements of the spermatozoa last only a
short time ; ten minutes after their escape they relax sen-
sibly ; in all the cases which I have observed, they have
ceased entirely after two hours and a half.*

The number of the anthericlia is very large ; it often
amounts to fifty on the same shoot. They first open at the
beginning of May ; but even at the end of June a good
number of ripe ones may still be found. Upon Pellice
growing in running water, which, as a rule, are barren, iso-
lated anthericlia are not mifrecmently found; but arche-
gonia are hardly ever met with.

Upon the shoots situated in the indentations of the fore edge
of those spring-shoots which bear anthericlia, oval, closely
packed cellular bodies are protruded, varying in number from
four to twelve; these are the first rudiments of the archegonia.
Immediately after their appearance, the young shoot makes a
further growth underneath them, but without attaining to

* Thuret has shown that spermatozoa of a like structure exist in all the
Muscineae. (' Ann. Sc. Nat.,' 3rd ser., vol. xvi). He has given very good
figures of those of Pellia (1. c, pi. x). Schacht's figures ('Die Pilaiizenzelle,'
Berlin, 1852, pi. v) do not exhibit correctly the relation of the cilia to the
body of the spermatozoid.

32 HOFMEISTER, ON

the same thickness as before. The archegonia, consequently,
appear to be seated upon the scarp produced on the upper
surface by the sudden diminution in thickness of the joint
of the stem (PI. V, fig. 1). The development and struc-
ture of their first rudiments correspond exactly to those of
the very young antheridia. A cell of the upper surface of
the yet very young shoot becomes slightly arched outwards ;
it divides by a septum inclined to the surface of the stem,
and the upper one of the newly formed cells divides by a
septum inclined in an opposite direction to the latter septum.
Whilst the division is repeated in the new terminal cell by a
septum perpendicular to the last and parallel to the last but
one, the last formed joint-cell divides by a vertical septum
into two cells whose basal outline is a quadrant. The
same process recurs in each second-youngest cell, whilst
the terminal cell divides anew by a septum inclined in a
direction opposite to that of the last. The archegonium
would have the appearance of a column consisting of
four rows of cells, but for the fact that in all the cells
of one of the four rows, immediately after the division
of the cell of the second order by a radial longitudinal
septum, a partition-wall appears which divides the cell into
an inner three-sided cell, surrounded by other cells, and an
outer cell, of which one of the four walls is free (PI. V,
figs. 3, 4). The young archegonium thus presents the ap-
pearance of a cylinder of cellular tissue, rounded above, con-
sisting of a central string of cells (as many as thirty in
number), which is surrounded by a single layer of four
cells. The central cellular string does not extend quite to
the base of the young archegonium, which base consists of
a short stalk, of the height of one or two cells, and com-
posed of four cells lying in the same plane (PL V, figs. 5,
G, 6*). The cells of the central string become filled, soon
after their formation, with a granular mucilage, in which
the nucleus lies imbedded in the form of a transparent
vesicle (PI. V, fig. 4). The undermost of those cells swells
considerably ; its nucleus also increases in size (PI. V,
fig. 5). The adjoining cells divide by longitudinal septa
as soon as the longitudinal growth of the archegonium is
finished (PI. V, figs. 5, 6, 7). The same division proceeds

THE HIGHER CRYPTOGAMIA. 33

to some extent (to the height of five cells), towards the
apex of the archegonium, the lower part of which thus
becomes enlarged. In the mean time, the horizontal
septa which divide the cells of the central string of
the archegonium from one another become dissolved
(PL V, fig. 5). A canal, filled with mucilage, and closed
above, thus originates in the longitudinal axis of the archego-
nium. The cells which form the arch over its upper end sud-
denly part from one another, bending themselves somewhat
backwards ; an open passage, not obstructed by any cell-
wall, now leads from the outside through the entire length
of the archegonium down to the large cell in its swollen
lower part (PI. V, figs. 6, 7). In the mean time there is
formed in the large cell a free spherical cell, enclosing
a central nucleus, and which, when fully grown, almost
fills the cavity of its mother-cell (PL V, figs. 6, 7).

During the development of the first archegonia a thin
lamella of cellular tissue grows out of the upper surface of
the flat stem, from the point of insertion of the archegonia
backwards. It follows the longitudinal growth of the
archegonia, inasmuch as the cells of its fore edge con-
tinually divide by transverse septa, and its side edges unite
with the thin prolongation of the shoot which extends
itself underneath (in front of) the archegonium (PL V,
fig. 2). A pouch-shaped covering thus originates, which
is open in the fore part, and encloses the archegonium. It
entirely corresponds in its whole development with the
perianth of the leafy Jungermanniae, especially in the fact
that it appears at a later period than the first rudiments of
the archeg-onia. Pellia must not be classed with the
Gyromitrise.

The above condition is attained by all those archegonia
whose longitudinal growth is terminated before the time
when the rudiments of the fruit begin to appear in one of
the archegonia enclosed in the same perianth with them-
selves. The time of the development of the archegonia
is very uncertain : the earliest open at the beginning of
May ; the latest in the middle of July. Even then, those
flowers which contain no rudiments of fruit exhibit abortive
archegonia, in which the walls of the canal of the neck and
the wall and contents of the large cell in the expanded

3

34 H0FME1STER, ON

lower portion are of a deep-brown colour. Of these
abortive archegonia some have only just burst at the apex,
some are still closed, and others again are in the earliest
stages of development.

I consider those archegonia whose apices have just
opened, and the cell-walls of whose necks have not yet
become brown, as in a state ready for impregnation ; and I
believe that, in order to effect such impregnation, it is
requisite that some, perhaps one only, of the motile threads
formed in the antheridia should reach the funnel-shaped
opening of the archegonium. I have not, indeed, seen the
spermatozoa of Pellia in that position, even if such be the
case with other liverworts, about which I shall speak here-
after. I have frequently found, however, that in those
flowers of Pellia to which I had applied a drop of water
containing ripe, opened antheridia, several (from three to
seven) archegonia have produced the rudiments of fruit
(PL V, fig. 9"). The circumstance, that the ripening of
the antheridia and the bursting of the archegonia begin and
end precisely at the same time, affords as good ground for
the above view as the more exact knowledge which we
possess with regard to mosses — a view, moreover,
which in all essential points has been entertained for an
equal length of time with regard to both liverworts and
mosses.

The outer cells of the expanded portion of the im-
pregnated archegonium divide rapidly several times one
after another, by radial septa, by longitudinal septa
parallel to the free outer walls, and by transverse septa ;
this cell-multiplication is most vigorous at the base of the
archegonium. All the newly formed cells become filled
with chlorophyll. Thus, very soon after the beginning of
the development of the rudiments of the fruit, the ex-
panded portion of the surrounding archegonium assumes
the form of a somewhat large, dark-green, cellular mass.
The neck of the archegonium remains unaltered.

The fruit is developed from the free spherical cell which
is enclosed in the central cell of the expanded por-
tion of the archegonium. That cell first divides by a
transverse septum into a lower and an upper cell, of which

THE HIGHER CRYPT0GAM1A. 35

the former is much the larger of the two, and the latter
has the shape of a segment of a sphere. The latter
divides by a longitudinal septum shewn in PI. V, fig. 8, which
represents the rudimentary fruit extracted entire. Each of
the two cells which have a semicircular basal outline is
divided after previous expansion in length, by a longitu-
dinal septum at right angles to the previous one, and
each of the four cells thus formed is divided anew by a
transverse septum. The young rudimentary fruit now
exhibits four apical cells (cells of the first order). Its
growth is carried on by continually repeated division of
these cells by means of horizontal septa.

In the first four interstitial cells thus formed, cell-multipli-
cation commences in the direction of their breadth and thick-
ness. Each of these cells (whose form is that of the quadrant
of a cylinder) divides by a longitudinal septum parallel to
the axis of the rudimentary fruit, cutting both the side
walls at an angle of 45°; and each of the four new outer
cells thereupon divides by a radial longitudinal septum.
In the next higher double pair of cells, the cell-multiplica-
tion does not proceed any further. Erom thence (going
upwards) the division is repeated in the eight outer cells by
a longitudinal septum turned towards the free outer surface,
and the following division takes place by a radial longi-
tudinal septum. By this time the rudimentary fruit has
the form of a short club (PI. V, fig. 9). Its upper end, howr-
ever, soon increases considerably in thickness by divisions
which take place in the cells of the apical surface by means
of septa inclined outwards from the longitudinal axis of the
organ, which divisions alternate with the longitudinal and
transverse divisions of these cells. The cells of the apex of
the rudimentary fruit exhibit, in consequence, when cut
longitudinally, a regular radiate arrangement, which arrange-
ment changes, in the lower part of the fruit, into one con-
sisting of parallel rows of cells (PI. V, fig. 10).

About two months after impregnation, the apical cells of the
young fruit cease to divide. An active cell-multiplication be-
gins instead in almost all its already formed constituent parts.
The cells of the upper clavate end, excepting the innermost

36 HOFMEISTER, ON

of them, divide by septa parallel to a tangent to the nearest
portion of the outer arcuate surface, which latter septa alter-
nate with others at right angles to them, and with radial
septa. The cellular mass, which thus increases in size, is
the future capsule. In the middle of the rudimentary fruit
the cells which eventually form its stalk divide, frequently
several times over, by means of horizontal septa exclusively.
There is thus formed a cylindrical column of about sixty
(12 measured diametrically) vertical rows of small tabu-
lar cells. The lower third part of the rudimentary fruit
ultimately exhibits a rapid increase in the number of its
cells, both in length and thickness — an increase which
diminishes gradually downwards. This end of the rudi-
mentary fruit assumes in consequence the form of a turnip;
its thickness very soon considerably surpasses that of the
cylindrical middle portion (PI. V, fig. 11). At this period
an active multiplication commences in the cells of the cir-
cumference of the short upper protuberance of the swollen
base of the young fruit. These cells, which form a girdle
of about four cells in height, divide first by horizontal septa
(PL V, fig. 11), and afterwards by septa parallel to a tan-
gent to the circumference. By this means there arises out
of the upper portion of the turnip-shaped enlargement of
the fruit-stalk a hollow cylinder, enclosing its columnar
portion. This sheath increases in length by continually re-
peated division of the cells of the free upper edge by means
of alternately inclined septa. Its cells of the second order
are soon divided anew by membranes at right angles to the
latter septa, the older lower cells being divided more fre-
quently than the upper younger ones. The free upper edge
of the hollow cylinder consists, in all its stages of develop-
ment, of a single layer of cells ; towards the base the number
of the cells continually increases. In the course of further
development, four (in exceptional cases three) triangular flaps,
enclosing the fruit-stalk upwards for a considerable distance,
are formed from the edge of the sheath, by means of a
locally increased intensity in the cell-multiplication in a
longitudinal direction. During the formation of the sheath,
the end of the fruit-stalk beneath it continues to increase in
thickness ; this increase terminates, as does also the multi-

THE HIGHER CRYPTOGAMIA. 37

plication of the cells of the sheath in a longitudinal direc-
tion, when the sheath has attained a length equal to a
fourth or a third part of the stalk of the young fruit which
is still enclosed in its caIyptra(Pl. V, fig. 13). At an early
period, even before the expiration of the third month from
the commencement of the rudiments of the fruit, a diffe-
rentiation of the tissue appears in its upper swollen end,
i. e. the future capsule. The cells of the outer surface
divide by septa perpendicular to this surface, and then
again by partitions also perpendicular to the arched outer
surface, cutting the last-formed septa at an angle of 1)0°.
The inner cells take no part in this division ; they appear,
therefore, eight times larger than the others ; in longitu-
dinal and also in transverse sections, the boundary of each
pair of cells of the outermost layer coincides with that of
one of the adjoining inner cells (PL V, fig. 11). At the
same time the walls of the inner cells of the young capsule
begin to thicken. The substance of the thickened walls
swells up very rapidly and extensively in water ; to such an
extent that, in cutting through a young fruit placed in water
upon the stage of the microscope, the cells of the interior
of the capsule immediately protrude laterally beyond the
wall of the capsule. The swollen gelatine is dispersed in
the water ; the primordial utricles of the cells become free,
and assume a spherical shape (PI. V, fig. 12). In order
to get an insight into the structure of the interior of the
young capsule, it is indispensable that it should be examined
in rectified spirit of wine. With tincture of iodine the
entire mass of its cell-walls becomes coloured a vinous red
or violet. Even after the differentiation of the wall from
the inner tissue of the young capsule, the cells of both in-
crease considerably. The cells of the lower part of the wall
divide by septa parallel to the outer surface ; consequently,
at the spot where the wall of the capsule adjoins the fruit-
stalk, that wall consists of two layers of cells. On the other
hand, the cells of the wall of the upper part and of the
apex of the young capsule divide exclusively by septa per-
pendicular to the outer surface (compare fig. 11 of PL V
with fig. 13). At the same time the cells of the interior,
especially those at the boundary of the wall of the capsule,

38 IIOFMEISTER, ON

increase in all three directions ; most actively in the neigh-
bourhood of the apex. By the coincidence of both methods
of multiplication of its cells, the hemispherical form of the
voimg capsule is changed, within a month, into a long oval
form (PI. V, fig. 13).

By the end of August the walls of the cells of the inte-
rior are entirely broken up and undistinguishable. The
free primordial utricles begin now to clothe themselves with
new and firmer cell-walls. They then exhibit a very dif-
ferent deportment. One portion of the cells becomes elon-
gated and spindle-shaped — the future elaters. A whole
string of cells lying in the longitudinal axis of the young
fruit assumes this spindle form ; around this string the
rest of the cells destined to form elaters are arranged, radi-
ating upwards (PI. V, fig. 37). Another portion of the
cells of the interior assumes a spherical form : these are
the mother- cells of the spores. In their fluid contents, very
numerous small chlorophyll - granules now make their
appearance.

The mother-cells retain the spherical form only for a
short time. By the first week of September their walls ex-
hibit four protuberances, each of which, situated at a
distance of 120° from the neighbouring one, constitutes an
arched surface, the basal outline of which is an equilateral
spherical triangle. These bulgings of the cell- wall become
rapidly more and more arched ; by the middle of Sep-
tember each mother-cell appears to be composed of four
oval sacs open at one end, which unite at an angle of 120°
with the open, more pointed ends, so as to form a quadrangu-
lar median space (PI. V, figs. 14, 15). Each of these bulgings
of the mother-cell contains a nucleus ; the mode of its origin,
as well as that of the primary central nucleus of the mother-
cell, (which latter nucleus has now disappeared,) is difficult
to make out, on account of the opaque cell-contents, which
consist of a thick mass of chlorophyll-granules. It is even
somewhat difficult to feel assured of Avhat is an undoubted
fact, viz., the presence of a secondary nucleus in each of
the bulgings of the mother-cell.

At the boundaries of the four protuberances of the mother-
cell, the inner wall of the latter becomes much more thick-

THE HIGHER CRYPTOGAMIA. 39

ened than in its other parts. Six bands are formed,
which are attached to the inner wall, and protrude inwards.
At their first appearance, in the middle of September, they
are tolerably flat, but increase slowly in height until the
beginning of December (PI. V, fig. 17). The median space
by which the four protuberances of the mother-cell are in
continuous communication * is thereby narrowed ; rather
narrow circular cavities lead from it to the four protuber-
ances. It is now filled exclusively with transparent fluid
matter as clear as water ; chlorophyll-granules and granules
of mucilage are as yet found only in the protuberances.
Suddenly each of the latter appears separated from the
quadrangular median space of the mother-cell, by a wall
convex towards the interior (PL V, fig. 17). This delicate
membrane is probably not mounted upon the edge of the
broad ledge which protrudes into the median space, but
clings to its surface, and encloses the entire contents of
the protuberance, which, consequently, now represents a
very delicate-walled oval cell, i. e. the young spore. By
the dissolution of that portion of the wall of the latter
cell which belongs to the protuberance of the mother-cell,
the space very soon becomes free ; I have reason to sup-
pose that this occurs within forty-eight hours after the
spore has become individualised. The six thickened bands,
on the other hand, which consist of glass-like cellulose,
and which unite to form the skeleton of an uneven-sur-
faced quadrangular figure, last for several days ; they are
to be found in large numbers amongst the escaped spores,
and are most elegant microscopical objects (PI. V, fig. 20).
The spores of Pellia exhibit in the course of their develop-
ment several peculiarities, which are of importance in the
study of cell-formation. That the walls of the special
mother-cells grow gradually inwards from the inner wall of
the mother- cell is placed beyond a doubt, as wrell by the
slow growth of the bands above mentioned, as also by the
fact that, in Pellia, the walls in question are normally only

* This appears perfectly clearly when one of the protuberances of a mother-
cell which has been lying in water bursts, and a portion of the contents escapes
through the fissure (a ver^ frequeut occurrence). The fluid contents of the
uninjured protuberances of the mother-cell then flow slowly, mixed with chloro-
phyll-granules, into the one which has been ruptured.

40 IIOFMEISTER, ON

developed to the extent of two third parts, and never com-
bine to form partition-walls. If there were any need of ad-
ditional evidence in opposition to the theory again brought
forward by Karsten, viz., that vesicles too small to be seen
with the microscope gradually grow into daughter-cells and
occupy the entire space of the mother-cell, it would be
afforded by the existence for three months before, as well
as during and after the individualization of the spore,
of a secondary nucleus in each of the protuberances of the
mother-cell, which protuberances for a long period freely
communicate with one another. The circumstance that
the four protuberances of the mother-cell of Pellia, which
eventually become the spores, leave a space between them
filled only with water, is a convincing proof of the inde-
pendent nature of the halves of the primordial utricle.

The young spore divides by a transverse septum very
shortly after it has become clothed with a proper membrane ;
usually whilst it remains attached to its three sister-spores
by the remnants of the mother-cell (PI. V, figs. 18, 19).
Upon the commencement of this process the central nucleus
of the spore, disappears ; two new nuclei, of a flattened ellip-
soidal form, appear (PI. V, fig. 18). The numerous small
chlorophyll-granules through which the nucleus is faintly
seen, thereupon appear separated into two groups, each
filling one half of the spore, so that in its equator there is
formed a narrow zone of transparent mucilaginous fluid,
free from granules and chlorophyll -bodies. This light space
appears suddenly traversed by a very delicate but sharply
defined line, which is the side view of a septum passing
through the spore (PL V, fig. 21). The same process is
shortly afterwards repeated in each of the two semi-ellip-
soidal cells which are thus formed (PL V, figs. 19, 22, 24).
At this time (the beginning of December) one of the four
middle cells sometimes divides by a longitudinal septum
also (PL V, fig. 23). Henceforth the number of the cells
of the spore does not increase until its dispersion in the
spring of the next following year. The spore, however,
secretes over its whole extent a brownish, slightly trans-
parent outer membrane, covered on its external surface with
numerous very small asperities, which, when the spore is

THE HIGHER CRYPTOGAMIA. 41

ripe, renders the boundary lines of the four or five eells of
which the spore is composed very indistinct.

Under cultivation, irregularities in the development of
the spores of Pellia are rather frequent. The primary
halves of young spores sometimes divide by longitudinal
septa instead of by transverse ones (PL V, fig. 25). Not
unfrequently all the mother-cells of a fruit become abortive
shortly before the period of the independent existence of
the spores, excepting a few of the mother-cells, which in
such a case attain almost double the usual size.

The vegetative development of the rest of the species
mentioned in the title of this chapter differs materially from
that of Pellia. The growth of Metzgeria furcata in length
and breadth is discussed by Nageli, in his essay on the
study of cell-multiplication, " Wachsthumsgeschichte der
Laub. und Lebermoose" (' Zeitschrift f. Botanik,' Heft 2).
My view of the process, as the following remarks will show,
differs in some subordinate points from that of Nageli.

The longitudinal growth of the strap-shaped stem, which
is slightly rounded at the apex, results from the conti-
nually repeated formation of septa, spreading right and left,
and perpendicular to the surface of the stem (PL V, figs.
26, 27, 28). The cells of the second order thus produced,
whose basal outline is a rather long five-sided figure,
divide first by a septum at right angles to the side walls and
perpendicular to the surface of the stem. In the outer-
most one of the newly formed cells the same process is
repeated again : a septum appears parallel to the one last
formed, or else this cell, as well as its inner sister-cell,
divides by a longitudinal septum parallel to its side walls.
In the former case the shoot grows in breadth ; in the latter
in length. In both cases the division is repeated several
times, always in the outermost cells, by septa at right angles
to the side walls. The development of each shoot begins
with the second form of cell-multiplication of the cells of
the second order ; as the longitudinal growth draws to
a close, the shoot is prepared for furcate ramification
(PL V, fig. 28), and thus the first form of cell-multiplica-
tion steps in. In each of the masses of cells which are
formed by the division of a cell of the second order, septa

42 HOFMEISTER, ON

parallel to the surface of the stem are only found in the one
innermost cell adjoining the longitudinal axis of the shoot.
After the first division of this kind, the formation of a
horizontal septum is repeated twice in each of the under
cells. The middle line of the stem consequently consists
of two parallel rows of four tabular cells one above another ;
the remaining part of the stern is a single superficies of
cells. Both the inner pairs of cells of the mid-rib which
protrudes from the lower side, divide by longitudinal septa
at right angles to the surface of the stem ; they are, there-
fore, about half the size of the adjoining cells of the upper
and under sides (PL V, fig. 29). Sometimes the cells of the
underside of the mid-rib follow in this division. The under
side of the fore edge of the mid-rib sends out numerous bicel-
lular hairs with a swollen terminal cell, and which, bending
themselves upwards, enclose to a certain extent the growing
end of the stem. The entire under surface of the stem
sends out rootlets, which are especially numerous on the
mid-rib and the side edges. The young cells exhibit a
nucleus with transparent fluid contents, which is freely
suspended in the slightly granular cell-sap. The nucleus
lasts for a long time, and, by means of the chlorophyll ad-
herent to its exterior, it is perceptible even in older cells,
where its contents refract the transmitted light much in
the same manner as the fluid contents of the cell. The
chlorophyll-granules of Metzgeria are amongst the smallest
in the vegetable kingdom.

Adventitious shoots are often developed from individual
cells of the edge or of the under side of the mid-rib
of plants growing in dry situations. The cell-multiplica-
tion in such shoots, which is very easy to observe, takes place
in precisely the same manner as it does in growing primary
shoots (PI. V, fig. 26). Vigorous adventitious shoots,
whilst still very young, form a mid-rib in the same manner
as the growing primary shoot, which mid-rib, by the divi-
sion of the cells lying between the first cell of the adventi-
tious shoot and the mid-rib of the primary shoot, is not
unfrequently prolonged backwards to the mid-rib of the
primary shoot. Sometimes, in unhealthy specimens, the
formation of cells of the third order is entirely suppressed ;

THE HIGHER CRYPTOGAMIA. 43

the shoot then consists simply of a double row of cells
(PL V, fig. 25).

A third mode of origin of lateral axes takes place at the
approach of fructification. On the under side of the mid-
rib, attached not exactly in the middle, but laterally either
to the right or left, there is formed, at some little distance
underneath the end of the stem, a cucullate leaf, in the
axil of which a branch is developed, but only to such an
extent as to form a flat cushion-shaped process. On its
upper surface are produced either archegonia or antheridia.
The antheridia, in structure and development, are exactly
like those of most of the leafy Jungermanniae, e. g. Radula
complanata. The archegonia, which are short and thick, and
only six cells in height, are situated, like the antheridia,
usually from four to seven in number, in the axil of a leaf.
Their regular mode of cell-development resembles that of
Pellia ; in Metzgeria, also, the large size of the cells of
the archegonium facilitates observation (PL V, fig. 30). I
have not had an opportunity of investigating the develop-
ment of the fruit of Metzgeria. In spite of the countless
multitudes of apparently healthy archegonia and antheridia
produced by the thick patches of Metzgeria fur cat a,
which in our hilly districts clothe the masses of rock
in shady, moderately damp localities, the fruit is very
rarely met with. Probably, the cause of this remarkable
fact is to be found in the drought which prevails in the
habitats of the plants at the period of the ripening of the
antheridia, viz., the middle of June.

The species of Aneura {A. pinguis and vndtifda), not-
withstanding the great difference of their habit from that
of Metzgeria, exhibit the same kind of development at the
ends of the stem (PL VI, figs. 2, 11). There is, however, one
essential difference, viz., that the cells of the second order,
even before their division by the septa perpendicular to the
surface of the stem, divide by septa paratlel to that surface.
This division is repeated rapidly and frequently, after
the manner of the growth (in thickness) of Pellia (PL VI,
figs. 3, 12), so that the shoot increases very rapidly in
thickness ; longitudinal sections through its growing end
have a parabolic form.

44

HOFMEISTER, ON

The ramification of the stem takes place in the same
manner as in Metzgeria furcata. In Aneura, however, the
growth of one of the young shoots in a forward direction
exceeds that of the other, which latter, at a very early
period, appears in consequence to be pushed on one side.
This more vigorous development takes place alternately
and regularly on each occasion of the division of the end
of the stem, occurring at one division in the shoot pro-
duced on the right side of the apical cell, and at the next
division in the shoot produced on the left side. In conse-
quence of this, Aneura exhibits a median principal axis,
and lateral axes with normally limited growth. In the side
shoots of Aneura multifida, whose longitudinal growth is
arrested, the parts adjoining the terminal bud on the right
and on the left often outgrow the former, so that the fore
edge of the branch appears deeply indented, resembling at
first sight the Marchantiese (PI. VI, fig. 1).

The ramification of Aneura and Metzgeria is therefore
truly furcate, like that of the stem of Selaginella ; that of
Pellia is not truly so, but resembles the ramification of
Viscum, the cause of which lies in the fact that the develop-
ment of each terminal shoot in Pellia is limited.

The archegonia of Aneura originate at the apex of very
short side-shoots of the second or third order. In their
origin and nature they resemble those of Metzgeria. Under-
neath their point of attachment there is produced, contempo-
raneously with the commencement of their formation, a
circle of small leaves, from four to six cells in height, con-
sisting at the base of from three to four cells, and at the
apex of a single cell.

When the large cell in the interior of the flask-shaped
portion of the archegonium of Aneura multifida * first
begins to be transformed into the rudiments of the fruit, a
series of very active divisions, which last for a long time,
commences in the cells of the archegonium, excepting those
of its neck. The lower part of the archegonium thus be-
comes a clavate, fleshy mass, which attains the size of a
millet-seed, even when the rudimentary fruit consists of

* I have not had the opportunity of examining the formation of the fruit in
A. puiguis.

THE HIGHER CR1PT0GAMIA. 45

only eleven cells. The cells of the branch bearing the
archegonia, which adjoin the place of attachment of the im-
pregnated archegoninm, also take part in this division. In
consequence of this, miinipregnatecl archegonia are often
carried up on to the oval cellular mass (the calyptra) formed
by the amalgamation of the flask-shaped portion of the im-
pregnated archegonium with the adjoining parenchyma of
the stem. By this means the growing calyptra, which in-
creases vastly in size, is bent upwards, so that its longitu-
dinal axis is at right angles to the surface of the stem (PL
VI, fig. 8).

The multiplication is very active in the cells of the calyp-
tra immediately under its apex, with the exception of the
epidermal cells, which continue of rather a large size, (PI.
VI, fig. 8), and grow out into long cylindrical papillae
(PL VI, fig. 4), upon whose outer wall a network of pro-
jecting bands is formed. The neck of the impregnated ar-
chegonium is usually thrust off at an early period (PL VI,
fig. 8).

The development of the fruit itself corresponds entirely
in essentials with that of Pellia (PL VI, figs. 5 — 8), but it
is altogether of a more slender construction. The fruit-
stalk consists of only two concentrical layers of cells ; the
enlargement at its lower end is much less developed ; the
cells destined to form the elaters and the rows of spore-
mother-cells are already differentiated (as in Prullania) at
the time when the entire contents of the young capsule
consist of a single horizontal layer of cells. Each indivi-
dual elater, however, divides by a transverse septum ; each
pair reaches from the base of the capsule to its upper arched
roof.

The antheridia of Aneura pinguis originate in precisely
the same manner as those of Pellia. A hemispherical or
shortly cylindrical cellular body, consisting of four short
longitudinal rows of cells, is formed by the multiplication of
one of the cells of the upper side of the stem (PL VI, figs.
14, 15); by the division of one of its middle cells into an
inner and an outer one, the ground is laid for the diffe-
rentiation of an outer layer, and an inner cellular mass
destined to produce spermatozoa (PL VI, fig. 12). A wall

48 HOEMEISTER, ON THE HIGHER CRYPTOGAMIA.

of cellular tissue is raised round the antheridium by the
multiplication of one of its adjoining epidermal cells.
Aneura multifield produces buds, often in very large num-
bers, near the ends of its shoots. Some of the cells of the
upper surface, not unfrequently whole groups of twenty or
more, protrude outwards in the form of an arch, become
quite filled with chlorophyll-granules, and divide by a sep-
tum passing transversely through the cell perpendicular to
the surface of the shoot ; the same thing occurs, but less
frequently, in the cells at the edge (PL VI, fig. 9). The
bicellular bud becomes free by the swelling up of the middle
layers of the wall of its mother-cell into a gelatinous sub-
stance which expands largely in water, in consequence of
which the outer lamella of the wall bursts, and the buds
escape. Their form is that of a somewhat elongated ellip-
soid, strongly constricted at its equator; its outline brings
to mind that of many of the Desmidiese (PI. VI, fig. 10).
The development of the buds into a new plant begins with
the repeated division of one of their cells by alternately in-
clined septa. .

CHAPTER III.

LEAFY JUNGERMANNLE.

The transition from the leafless to the leafy Junger-
manniae is a very gradual one ; it passes through an un-
broken series of gentle intermediate stages. One genus
(Diplolacna) which apparently coincides with Aneura in all
its vegetative phenomena, except that it has inferior leaves,
is followed by the peculiarly formed genus Blasia, whose
stem when young exhibits, in transverse section, the form
of an ellipse, and when more advanced, is drawn out in
breadth so as to become foliaceous — a genus whose superior
and inferior leaves differ in shape, the former having en-
tire, the latter denticulate, margins. Allied to these is the
genus Fossombronia, which has a stem only slightly ex-
panded, but nevertheless always much flattened on the
upper side, and bearing only superior leaves : this genus
differs very little in the relative size of its stem and leaves
from many of the leafy Jungermannige taken in the most
limited sense.

The most remarkable member of this series of tran-
sitional forms is, beyond all question, Blasia pusilla. In
perfect shoots, that is to say, shoots bearing bud-recep-
tacles, the stem is so much widened that its edges seem
to amalgamate with the horizontally-arranged superior
leaves ; these leaves have been somewhat generally con-
sidered to be, and have been described as, " segments of
the flat stem." On the shoots just mentioned it is only
the inferior leaves which look really like leaves ; they are
denticulate scales on the right and left of the longitudinal rib
which protrudes from the under side, and which throws out
roots (PL VI, fig. 16). At the upper end of the stem is found

4-8 HOFMEISTER, ON

the terminal bud, which is surrounded by closely crowded
superior and inferior leaves, and which is usually very
difficult to make out, on account of the buds situated near
it and upon it ; this terminal bud is a mass of cellular
tissue, which, in shoots capable of further development, has
a much-flattened conical form, whilst in shoots whose
longitudinal growth has terminated it is flat and emarginate
at the apex ; it bears on its under side amphigastria, and
on the other side scale-like, inbricated superior leaves.
Numerous hairs, similar to those on the very young parts of
Pellia and Aneura, are scattered amongst the most newly
formed leaves (PL VI, figs. 17, 18).

It is well known that numerous reproductive buds are
formed on the under side of the stem of Blasia. Their
mode of development is very like that of the similar organs
in Anthoceros. The contents of one of the inner cells of
the tissue of the stem (which cells are only separated from
the under side by a single cellular layer) become transformed
into a cell occupying the whole cavity of the mother-cell.
This daughter-cell changes into a roundish body, composed
of small cubical cells, which contain numerous very small
chlorophyll-bodies of a dark bluish-green colour. The
cellular layer of the under surface of the stem which covers
the reproductive buds becomes swollen to a hemispherical
shape by the increase in size of the latter.

1 have not seen these reproductive buds develope into
young plants. Corda figures their germination in Sturm's
Deutschl. Flora, II abth., taf. 32. Bischoff treats this
figure as a product of the author's imagination. I do not
agree with Bischoff 's opinion. It is true that the branched
rootlets which Corda represents are not found in any liver-
wort. This portion of the figure is, at all events, erroneous.
I consider it, however, beyond dispute that the organs in
question are really reproductive buds, judging from the
analogy which they bear to the undoubted buds of Antho-
ceros which originate in like manner. If old buds of
Blasia are opened under water, their cells separate from
one another in the surrounding fluid. The like phenomenon
occurs in the undoubted buds of Anthoceros and Riccia,
if the surrounding tissue continues to retain its vitality

THE HIGHER CRYPTOGAMIA. 49

for a very long time. It depends, certainly, only upon the
decay and internal disintegration of the buds.

Blasia differs from all other leafy liverworts in the fact of
its producing these reproductive organs, but still more in the
fact that the well-known flask- shaped bud-ciips are formed
upon its upper side.

The cell-multiplication of the terminal bud of Blasia very
much resembles that of Anthoceros, or of the young plants
of Pellia. The apical cell continues to divide repeatedly by
septa inclined alternately upwards and downwards (PI. VI,
figs. 19, 20). The cells of the second order divide by a
septum coinciding with the longitudinal direction of the
stem, and perpendicular to its surface. The frequent repe-
tition of the formation of these parallel septa in the two
halves of the stem causes the stem to increase rapidly in
width (PL VI, tigs. 17, 18). By the division of the cells of
the second order (and their daughter-cells) by septa parallel
to the surface of the stem, the stem increases in thickness
(PI. VI, figs. 19, 20). At the spot where a bud-receptacle
is about to be formed, this latter cell-multiplication ceases
at a very early period, even as early as in the cells of the
second order, whilst it continues in the neighbouring cells.
A circular depression is thus formed on the upper side of
the stem, close to its growing end, and quite covered by the
youngest superior leaves (PI. VI, fig. 20). Individual cells
of the base and sides of each depression send forth clavate
papillae, which are soon separated from the original cavity of
the mother-cell by a transverse septum (PI. VI, fig. 20). After
the apical cell of these short, hair-like papillae has divided
two or three times by transverse septa, the hemispherical
terminal cell divides by a longitudinal septum. In this
way a process of cell- format ion originates, which soon leads
to the production of a globular (or polyhedral) cellular
mass, viz., a reproductive bud, which is attached to the '
above-mentioned depression in the upper surface of the
stem, by means of a hyaline stalk, consisting of one or two
narrow cylindrical cells, with clear fluid watery contents.
The arrangement of the cells of the reproductive buds cor-
responds with that of the terminal bud of the stem (PI. VI,
fig. 21).

4

50 1IOFMEISTER, ON

Soon after the commencement of the development of the
first reproductive buds, the margins of the depression in
which they originate become elevated like walls— the eleva-
tion commencing with the hinder margin (PL VI, fig. 20).
A cylindrical tube, open above, is formed over the depres-
sion in which the buds are generated (PL VI, fig. 21).
The cells of the bud-receptacle itself, and those of the
lower part of its growing margin, take part in the longi-
tudinal elongation which now commences in the tissue of
the stem. The cells of the upper part of the above tube
extend themselves upwards only ; those of its free margin
continue to divide by transverse septa. By this means the
lower part of the bud-receptacle becomes elongato-lageni-
form ; the open tube appears inserted in its upper end.

Reproductive buds now make their appearance on the
inner-side also of the upper arched surface of the bud-
receptacle. The inner cavity of the receptacle is filled, like
those of the Marchantiese, with dense transparent slime, in
which numerous short greenish threads, too narrow to
admit of being measured, are imbedded (PL VI, fig. 22).
(Are they the rudiments of fungi?) A very striking
peculiarity is exhibited by the rudimentary reproductive
buds in these cells, which are destined for a process of
active multiplication. Their contents are as clear as water.
No nucleus of any kind is to be seen. It is only on rare
occasions that solid bodies are found in the cell-sap, in the
form of from one to three sharply defined, angular, very
small bodies with exceedingly active molecular motion
(PL VI, fig. 22s). Concentrated tincture of iodine precipi-
tates a scarcely perceptible quantity of a yellowish-brown
substance upon the inner wall of the cell, even when the
tincture is considerably heated. When the bud (omitting
the stalk) has become 4-5 cellular, a nucleus is for the first
time perceptible in each of the cells, contemporaneously
with the appearance of the first small chlorophyll bodies,
which are of a beautiful emerald green. The number of
these increases considerably towards the period of the
perfecting of the bud. At this time numerous drops of a
clear, yellow, fatty oil make their appearance in the cells of
the buds. The chlorophyll changes colour. Ultimately the

THE HIGHER CRYPTOGAMIA. 51

stalk of the ripe bud detaches itself from the wall of the
receptacle ; the bud is ejected through the narrow tube of
the lageniform receptacle, and becomes free. The escape of
the buds is doubtless caused by the pressure which the
numerous, rapidly-groVing young buds, necessarily exert
upon the mucilaginous contents of their receptacle, which
contents are thereby in constant motion towards the opening
in its neck.

It is stated in some books that the bud-receptacles of
Blasia are closed when young, and open at the top at a
later period (see Nees v. Esenbeck, Naturgesch. d. Europ.
Lebermoose, B. 3, s. 395). An incorrect figure of Hed-
wig's has probably given rise to this erroneous notion (see
' Theoria generationis/ ed. 2, t. xxx, fig. 9).

The germination of the German liverworts, irrespective
of the very special wonderful development of the spores of
Blasia (see the beautiful observations of Gottsche, N. A. A.
C. L., vol. xx, p. 1 ; and the supplementary ones of
Gronland, ' Ann. Sc. Nat.' ser. iv, t. i, pi. 3) ; exhibits at
least three essentially different methods of development.

Frullania dilatata has the largest spores. They are longish
and tetraheclral, with rounded edges and angles ; more
rarely spherical. The inner membrane is as clear as glass,
and not very delicate ; the outer one is thin, membranous,
and of a yellowish-brown colour, beset at regular distances
with circular groups of brown protuberances (PI. XI, fig.
27). The contents consist of a yellowish, viscous fluid, in
which numerous granules are suspended. In the middle
point of the spore a roundish ball of opaque matter (a
nucleus surrounded by granules) is indistinctly seen. The
germination of the spores commences as early as the fifth
day after sowing. Numerous very small chlorophyll bodies
are formed in the fluid contents. The primary central nucleus
disappears, and in its place are found two new ellipsoidal
nuclei. From eight to twelve days after sowing, these
nuclei appear separated by a delicate line, which is the side-
view of a septum, dividing the spore into two cells (PI. XI,
figs. 20, 29). One of these cells divides rapidly and con-
tinually by alternately inclined septa (PI. XI, figs. 30 — 34) ;
the daughter- cells thus formed divide by radial septa. The

52 HOFMEISTER, ON

cells of the third order divide by septa parallel to the longi-
tudinal axis of the germinating spore, and cutting the side
walls at an angle of 45°. In the outermost new cells of
the fourth order, vertical and radial septa are formed, and
then horizontal septa. In this way the spore, in the course
of a month, is transformed into an oval cellular mass, whose
longitudinal diameter is from three to five times the length
of that of the ripe spore. The outer membrane of the
spore, which expands considerably, surrounds the continually-
increasing cellular body for some time, until eventually
it bursts (PI. XI, figs. 32, 33) ; the remnants of it often
remain for a long time adherent to the base of the cellular
body (PI. XI, fig. 37).

One of the basal cells of the germ -plant now grows into
a root with a thick wall and a narrow cavity, precisely simi-
lar to those which are developed by the perfect plant (PL
XI, fig. 35). All the cells of the upper surface of the germ-
plant, excepting those of the apex, protrude outwards in the
form of arched papillae. Ten days later the first leaves
sprout forth close under the apex of the germ-plant, placed
opposite one another on the stem at equal distances (PL
XI, fig. 37).- The arrangement of their cells shows that
their growth results from the repeated division of a cell of
the surface of the stem, by means of alternately inclined
septa at right angles to the surface of the leaf. The second
pair of leaves stands exactly over the first; the two other
rows of leaves of the older plants first appear at a later
period. The form of these earliest leaves (ovato-acuminate)
is moreover very different from the two-lobed closely-folded
later leaves. The terminal bud of the stem is situated
between the leaves, in the form of a blunt, conical protu-
berance (PL XI, fig. 38). In this bud also the growrth
manifestly results from the division of an apical cell, by
means of alternately inclined septa.

The small globular spores of Jwngermannia bicuspidata
have a brittle, finely granular, brownish outer membrane ;
they contain a mucilaginous opaque fluid (PL IX, fig. 1).
The cushion-like masses of Palmelleae which are usually
found under the patches of this liverwort afford a peculiarly
suitable substratum for the germination of the spores. As

THE HIGHER CRYPTOGAMIA . 53

early as the eighth day after the spores have been scattered
over the moist, slimy mass, the expanding inner membrane
ruptures the outer membrane, and protrudes in a vesicular
form through the fissure (PL IX, fig. 2). It contains numer-
ous very beautiful, small, emerald-green chlorophyll bodies.
The protruding portion of the inner membrane is soon
divided from the remainder of it by a transverse septum.
By continual division of the fore-cell (that one, namely,
which is furthest from the remnants of the exosporium) by
means of transverse septa, — which septa are always preceded
(as in higher plants) by the appearance of two new nuclei in
the mother-cell (PI. IX, figs. 3 — 7) — the germinating spore
is converted, within a month after it has been sown, into a
simple row of cells, seven or eight in number.

In the apical cell, and often also in the interstitial cells,
with the exception of the one or two lowest, division by
longitudinal septa now commences contemporaneously with
an active longitudinal growth of the germ-plant, which latter
growth results from the division of the apical cell by means of
alternately inclined septa. In this way there originates a
small band, formed of a single layer of cells, lying side by
side in pairs (PI. IX, fig. 8), near the lower end of which
a slight thickening of the cellular tissue is often found,
originating from the division by more than one longitu-
dinal septum, of some of the interstitial cells of the cellular
thread produced by the germinating spore. The ribbon-
shape of the fore end of the germ -plant is soon changed to
that of a cylinder through the division by radial longitu-
dinal septa of the cells of the second order, produced by
the division of the terminal cell by inclined septa (PI. IX,
figs. 104, 11M,C). Prom some of these cells short cellular
branches sprout out always close under the septum dividing
the particular cell from the next higher one. These
branches are soon separated from the inner cavity of their
mother-cell by a transverse septum. They are arranged in
two vertical rows, the lower being placed (with respect to
their attitude) irregularly upon the germ- plant, the upper
ones being very regularly alternate (PI. IX, fig. 9). The
lower ones do not undergo any change, but in the third or
fifth, reckoned from below, division occurs by a transverse

54 HOFMEISTER, ON

septum; in the higher ones this division is repeated in
the terminal cell, so that they present the appearance of
3-cellular rows of cells. Those which originate at a later
period exhibit longitudinal septa in their basal cells, and a
furcate ramification at the apex ; they resemble now, even
in their outline, the leaves of the plant (PI. IX, fig. 9).
Higher up, in more advanced germ-plants, perfect leaves
appear in the place of the above rows of cells. Individual
points of the wall of many of the cells of the underside of the
germ-plant often develope, even at an early period, into root-
lets, and penetrate into the substratum (PI. IX, fig. 10).
In isolated cases the longitudinal growth of the first shoot
of the germinating plant is suppressed ; a new shoot then
arises near to, and underneath, the apex, whose cells exhibit,
at a little distance above the place of origin of the shoot,
the same arrangement as that which is found at the apices
of germ-plants in a more advanced state of development,
and which are commencing to form leaves (PL IX, fig. 12,
I26).*

Jungermannia divaricata, Engl. Bot., and Alicularia
scalaris (PL VII, fig. 11), of both of which I have found
spores just germinating and half developed germ-plants,
appear to germinate in the same manner, in all respects, as
Jungermannia bicuspidata. The same is the case, according
to Gronland (1. c. PL I), in Sarcoscyphus Funkii and Junger-
mannia crenidata. The germination of Lophocolea hetero-
pltylla coincides generally with that of /. divaricata. Here,
however, the delicate brownish outer spore-membrane is
not ruptured by the expanding inner membrane, but is only
gradually stretched, until finally it disappears in the further
progress of the germination. The small globular spores scat-
tered over decaying bark, swell to three times their original
size within a few clays. Numerous chlorophyll bodies are
produced at the same time in their fluid contents ; a
nucleus becomes clearlv visible in the centre of the cell, and
may even be seen, although with difficulty, whilst the spore
is still enclosed in the capsule. This nucleus vanishes, and

* Gronland has observed that the germ-plant whilst exhibiting only a single
row of cells, not (infrequently ramifies ; a fact which I have not observed. (See
'Ann. Sc. Nat.' iv ser. 1, p. 15.)

THE HIGHER CRYPTOGAMIA. 55

two new nuclei make their appearance. The germinating
spore divides into two halves by a transverse septum
originating between the two nuclei. The same process is
repeated in one of the newly-produced cells ; in this way a
short, simple row of cells is formed (PI. IX, figs. 17 — 25).
The terminal cell of the row swells to the shape of a head,
and divides by a longitudinal septum. Prom the continual
division of the terminal cells a small band of cellular tissue
is produced, similar to the second stage of development of
the germ-plant of J. bicuspidata (PI. IX, fig. 26), and
which, as in that plant, produces lateral regularly-placed
hairs, hair-like roots on the underside, and finally, after
further development, perfect leaves at its apex (PI. IX,
fig. 26). At the time of the first appearance of the latter
1 always found the oldest hinder part of the plant entirely
dead.

The spores of Badida complanata are tolerably large,
globular, and clothed with a brownish-yellow exosporium.
In the fluid contents, which enclose numerous very small
chlorophyll bodies, a very well - defined large nucleus
is suspended (PI. XI, fig. 16). Twenty-four hours only
after sowing the spores upon moist bark the greater
number of them begin to germinate ; some lie quiescent
for weeks, and then germinate suddenly. Two nuclei,
which are very prominent as light circular spaces in the
opaque cell-sap, appear in the place of the primary central
nucleus. Between them a septum is formed, dividing the
spore into two halves (PI. XI, fig. 17). The division is
repeated in the newly-formed cells, but by septa at right
angles to the first septum (PL XI, fig. 18) ; four cells
having the form of quadrants of a sphere have now been
formed in the spore. Each of these divides, in the first
instance, by a septum either parallel to the first-formed
septum or perpendicular to it (PL XI, figs. 19, 20) ; the
four four- sided ones of the newly-formed cells divide by septa
cutting the last-formed septa at an angle of 90° (PL XI,
fig. 20*'^). The body which has been formed by the
division of the spore-cell, and which now consists of twelve
cells, four central and eight peripheral ones, has now a
well-defined cake-like shape. Henceforth, the multiplica-

56 HOJfMEISTER, ON

tion of the cells takes place exclusively in the direction of
one surface, with the exception of a single division of all
the cells which takes place by septa parallel to the surface,
sometimes at this period (PI. XI, fig. 21), and sometimes
rather later. The underside of the flat expansion sends out
rootlets with very narrow cavities, exactly similar to those
produced from the lower leaf-lobes of fully developed plants.
The cells of the margin, as well as those of the middle,
multiply continually by division caused by septa perpendi-
cular to the surfaces of the plate-shaped body (PI. XI,
figs. 23, 24). Ultimately, five months after sowing, a
small protuberance of cellular tissue is seen at the margin
of the flat germ-plant, which is soon recognised as the
first commencement of the leafy stem by the fact of its
producing rudimentary leaves under its apex (PI. XI, figs.
25, 26). The arrangement of the cells of the terminal
bud of the young stem shows clearly that its longitudinal
growth is the result of the continual division of an apical
cell by alternately-inclined septa (PL XI, fig. 26).

The normal mode of cell-multiplication in the growing
end of the stem of developed plants of the leafy Junger-
mannise, is most difficult to ascertain. The terminal bud
protrudes very slightly above the place of origin of the
youngest leaf; the older leaves embrace the bud more
closely than in any other plants I know. Numerous hairs
which are developed upon and between the youngest leaves
interfere with the observation ; the contents of the youngest
cells (viz. a thick mucilage in which numerous, often closely-
packed chlorophyll bodies are imbedded) are almost opaque ;
all which matters present almost insuperable obstacles to
the observer. With the exception of the instances brought
forward in treating of the germination, there have been but
few cases in which I have arrived at clear results, viz.,
in Frullania dilatata (PI. XI, fig. 9, 10), LopJtocolea biden-
tata (PL IX, fig. 13), Trichocolea tomentella (PL VIII,
fig, 4), and Jmigermannia bicuspidata (PL VIII, 12, "■ b) ; the
shoots here examined were the few-leaved shoots which
break out between the leaves, and which originate from
adventitious buds. They all agree in essentials with one
another, as also with the modes of development of the nidi-

THE HIGHER CRYPTOGAMIA. 57

mentary stem observed in the germination of different
species. One apical cell divides continually by septa alter-
nately inclined in different directions. In Jungermannia
bicuspidata, and Frullania dilatata, these septa are directed
alternately right and left; the apical cell has the form
of a segment of a sphere. The cells of the second order
are divided by radial longitudinal septa. In each of
the three-sided daughter-cells a septum is formed, cutting
the side walls at an angle of 45°, and dividing the cell into
an inner and an outer one. The latter is divided by a
radial longitudinal septum into two halves ; the growth of
the circumference, even in leafy shoots, terminates at this
point in J. bicuspidata and many nearly allied species, such
as J. connivens, and divaricata. In these species both layers
of cells, but more frequently only the outer one, continue
to divide by horizontal septa; the four inner cells again
divide by longitudinal septa, parallel to the axis ; and after-
wards at least two, often four of the newly- formed narrow
cells of the interior of the stem, divide by radial septa.
The axis of the stem consists, consequently, of somewhat
elongated cells, which are much narrower than those of the
single cortical cellular layer. Hence, also, there arises the
indication of a vascular bundle, traversing the longitudinal
axis of the stem. At a similar stage of the development of
the stem in thickness — the lowest which occurs in the
vegetable kingdom, from the leafy mosses upwards — the
germ-plants of all observed species make a stand ; ultimately
and by degrees thicker shoots are formed, which produce
the rudiments of fruit.

The great variety of forms in the leaves of Jungermannia
is only partly accounted for by the rules of development of
their cells. Many of the most striking varieties of form in
perfect leaves are produced by an anomalous expansion of
small groups of cells, and a multiplication, commencing at
a late period, in individual cells of the margin of the leaf.
The same difficulties which interfere with a clear ascertain-
ment of the structure of the terminal bud, hinder to a still
greater extent the observation of the first stages of develop-
ment of the leaves. I have only been able in a few cases
to observe directly that the leaf originates in the continual

58 HOFMEISTEIt, ON

division of a single cell of the upper surface of the stem,
which protrudes in an arched form, at an early period, above
the bounding surface of the stem. One of these cases is
Fossonibronia pusilla. Here the leaf, at its first appearance,
is exactly like a short hair ; the papillseform protruding cell
of the upper surface of the stem is soon separated from the
original cavity of the cell by a transverse septum, and after-
wards divided by a septum parallel to the latter, into a
lower cylindrical, and an upper clavate cell. The fluid con-
tents of the latter are tolerably transparent, those of the
former exhibit numerous chlorophyll-granules (PI. IV,
fig. 25). The lower cell only, divides in rapid succession;
first by a transverse septum, and then the lower one
or both of the newly-formed cells, by a septum at right
angles to the last, and to the surface of the young leaf
(PL VI, fig. 27). The upper pair of cells of the third
order divide by transverse septa ; longitudinal septa appear
in the lower one, followed by transverse septa again in the
outer cells (PI. VI, fig. 26). The like succession of divisions
takes place in the lower of the two pairs of cells, which
originated in the transverse division of the two cells of the
third order adjoining the apical cell, and is repeated, (with
the recurrence of the transverse division of the upper of
these pairs of cells,) continually in the two newly-formed
cells lying nearer to the base of the leaf on the right and
left of the median line. In the mean time, by frequent
longitudinal division of the marginal cells of the lower part,
the leaf increases considerably in breadth (PL VI, fig. 28) ;
the one longitudinal half is always more vigorous than the
other. This multiplication lasts much longer at the base
of the leaf, where it keeps pace with and ultimately exceeds
the growth of the stem, than it does at the upper margin,
towards which it gradually diminishes. Individual cells of
the margin continue to multiply for a longer period than
their neighbours, repeating in miniature, in the mode of
their multiplication, the formation of the leaf; in conse-
quence of this the leaf assumes its multi-angular shape.

The rudimentary appendages of the leaves of the Lopho-
coleas are, as has been already observed, short rows of cells ;
the first rudiments of the leaves themselves are nothing

THE HIGHER CKYPT0GAM1A. 59

more than simple cells, produced by the cutting off
of short papillae by a transverse septum. This renders
it in the highest degree probable that a single cell of the
bounding surface of the stem is the mother-ceil of the leaf.
However at the period when the young leaf first appears
above the surface of the stem, it consists, when viewed from
above, of four cells arranged side by side, embracing more
than a fourth part of the stem (PL IX, fig. 14). The two
middle ones are considerably larger than the side ones.
The foundation for the two-pointed form of the leaf is
laid immediately upon the division of the middle cells by
septa, both at right angles to the median line of the leaf,
and diverging from it to the right and left. Each of the
two middle cells of the 4-cellular fore-edge of the leaf
developes a papillaeform prolongation, directed forwards
and at the same time obliquely outwards ; the outline of
each is parabolical, and each of them divides repeatedly by
transverse septa (PI. IX, fig. 15). The wide and low
interstitial cells thus produced are divided from once to
as many as eight times by septa parallel to the longitudinal
axes of the teeth of the leaves. The activity of this cell-
multiplication diminishes from beloAv upwards ; the tips of
the teeth of full-grown leaves consist of short simple rows
of cells. During the formation of the teeth, the number
of the cells of the lower part of the leaf continues to increase
considerably by longitudinal and transverse divisions. The
septa there formed are not always at right angles, or parallel
to the longitudinal axis of the leaf, but are often laterally
inclined to a considerable extent (PL IX, fig. 16). Frequent
irregularities in the arrangement of the cells are produced
thereby, especially in Lophocolea heterophylla.

In the latter plant the growth of the teeth on those leaves
which are intermediate between the two-pointed lower leaves,
and the entire upper leaves, is caused by division of the
terminal cells by alternately-inclined septa, not by septa
parallel to one another.

Jangermcmnia bicuspidata, and the closely allied /. conni-
vens and J. divaricata, comport themselves, in the matter
of leaf-development, similarly to the Lophocolese. In these
latter, however, the regularity of the arrangement of the
cells is much greater ; the cell-multiplication in the lower

60 HOFMEISTER, ON

undivided half of the leaf is very limited, often almost sup-
pressed in J. divaricata. The first rudiments of the two
points of the leaf in /. bicuspidata are of a very plump
form (PL VIII, figs. 8 — 10). In Ptilidium ciliare an active
multiplication of the cells of the superior leaves commences
at a late period, and is more clearly defined than even in
Lophocolea and /. bicuspidata. With it the formation of
the leaf commences by the protrusion outwards in the form
of an arch, of one of the stem-cells of the second order,
close underneath its apex; the protruding cell assumes
the form of a swollen seam, embracing nearly half the cir-
cumference of the stem (PI. VII, fig. 9, a). The cell divides
by a longitudinal septum radial to the axis of the stem ;
both halves of the seam are separated from the original
cavity of the cell by septa parallel to the outer surfaces of
the stem. Each of the two cells of the young leaf there-
upon developes itself independently in length. Each arches
itself outwards to some extent, so that the fore-edge of the
leaf exhibits two very blunt points ; thereupon each of the
cells divides by a transverse septum, which separates the
protruding portion from the original cell-cavity (PI. VIII,
tig. 9, b, where only half of the leaf is shown). This division
is repeated continually in each of the two apical cells. Each
interstitial cell (cells of the second order) is bisected by
a longitudinal septum. The cells of the third order divide
by septa, either parallel to the latter septum or converging
to it (PI. VII, fig. 51, c) ; thereupon the cells of the edge
of the leaf grow out into the long cilia which give the
specific name to the plant, extending themselves in the
form of papillae, and then repeatedly dividing in their apical
cell by transverse septa (PI. VII, figs. 7, 8). Ultimately,
longitudinal septa are formed in the lowest of the cells of
the second order of these excrescences of the edge of the
leaf. In highly developed leaves new cilia spring from the
marginal cells of these pointed appendages of the edge of the
leaf, originating in precisely the same manner as the parts
upon which they are borne. The leaf now consists of
two symmetrical halves, which have only a single row of
cells for their common basis, and are connected together
at the bottom only to the extent of a single cell (PI. VII,
fig. 8). It is this transverse row of cells which, by repeated

THE HIGHER CRYPTOGAMIA. 61

bisection, commencing at a late period, forms the cellular
surface, often ^'" in length, which carries the two-pointed
heads of the leaf.

In Frullania dilatata, which is furnished with such wide
leaves, the leaf, at its first appearance above the surface of
the stem (the periphery of which at this period exhibits only
four cells) consists of a single wide-stretched cell (PI. XI,
fig. 9). It divides at first, once or twice, by a transverse
septum ; the newly-formed cells then divide by longitudinal
septa (PL VIII, fig. 3). Each cell of the lower pair is now
divided by a septum coinciding with the longitudinal axis
of the leaf, and parallel to the first septum (PI. XI, fig.
8 a' h). The two apical cells of the rudiment of the leaf then
divide by septa almost at right angles to its longitudinal
axis, thus forming three-sided superior cells of the first
degree of the second order, and four-sided inferior trans-
versely extended cells of the second degree. The latter are
divided immediately after their formation into inner and
outer cells by means of a septum parallel to the longitudi-
nal axis of the leaf (PI. XI, fig. 8 c). The like processes
are repeated several times in the two apical cells of the
young leaf, so that the latter soon assumes the form of an oval
cellular surface, consisting of two inner rows of cells bounded
right and left by a row of marginal cells. The leaf soon
begins to increase in breadth by repeated division of the
marginal cells by means of septa parallel to the margin of
the leaf. At the same time the mode of multiplication of
the apical cells changes ; the division by means of a septum
almost at right angles to the longitudinal axis of the leaf,
is followed by a division by means of a septum, mounted
upon the latter septum, and only slightly diverging from
the median line of the leaf. The now four-sided elongated
apical cells continue to divide by alternate longitudinal and
transverse septa (PL XI, fig. 14). In the later stages of
development of the leaf, the cells produced by the division
of the two apical cells, both the marginal cells and the double
row of inner cells adjoining the median line of the leaf, are
divided soon after their formation by septa at right angles
to the longitudinal axis of the leaf (PL XI, fig. 13). This
division is followed by a division by means of septa inter-.

62 H0FME1STER, ON

secting the last-formed septa, and parallel to those lateral
cell -surfaces which are turned towards the median line of
the leaf. In the cells of the interior of the leaf this latter
division occurs once only ; in those of the margin it is
repeated sometimes as many as eight times in the outer-
most cells. The lower part of the leaf thus increases
considerably in breadth, in proportion to the increase in
circumference of the stem. As the longitudinal growth
of the leaf draws to a close, the two apical cells do not
keep pace with one another in their multiplication ; one
of them is usually a generation in advance of the other
(PI. XI, fig. 14). "

By the time that the leaf is of the height of four
cells, one of the marginal cells of its base begins to
protrude laterally in the form of an arch. The protu-
berance is soon separated from the original cell- cavity
by a transverse septum. By repeated transverse divi-
sion of the apical cell the latter is transformed into
a row of flattened cells, into a ribbon-shaped appendage
of the young leaf, embracing the stem (PL XI, fig. 8 °) ;
this is the first rudiment of the lower lobe (which
presses against the upper one) of the superior leaves.
It increases in breadth by the division of its cells by
means of septa parallel to the longitudinal axis. This
cell-division is repeated much oftener in the marginal
cells of that side of the lower leaf-lobe which is turned
away from the upper lobe, than in those of the opposite
side. It frequently does not continue in the cells nearest
to the apical cell. This latter cell grows regularly into
a club-shaped hair (PI. XI, fig. 2).

After the form of the leaf is thus prepared the cells
of its base divide by frequently alternating longitudinal
and transverse septa. The outline of the leaf is not
thereby changed, but the number of its cells is very
much increased, and the space over which the upper
leave-lobe coheres to the lower is considerably extended.

The first stages of development of the inferior leaves
of Friillania dilatata entirely resemble those of the bi-
dentate superior leaves of Lophocolea bidcntata, two teeth
being formed on the fore-edge in the same manner as

THE HIGHER CRYPTOGAMIA. 63

in the latter plant. Soon, however, a new process of
cell-formation appears at the side-edges of the leaf, under-
neath the place of origin of these teeth ; commencing by
a lateral expansion of one of the marginal cells, followed
by a cutting off, by means of a transverse septum, of the
protuberance thus formed, and by repeated transverse divi-
sion of the newly-formed cells. By this means the hitherto
double-pointed leaf becomes four-pointed.

The leaves of Radula camplanata are developed in all
their parts in a manner precisely similar to that of the
superior leaves of Frullania dilated a (PI. XI, fig. 15).
In this species, also, the apical cell of the lower lobe
after its last division usually grows out into a clavate
hair (PI. XI, fig. 1). The multiplication of the cells of
the base of the leaf lasts for a considerable time after
the termination of the division of the apical cells.

The arrangement of the cells in the leaves of the
round-leaved common Jungermannia? {J. curta, crenulata,
Alicularia scalar is) very much resembles the later condi-
tion of the upper lobe of the superior leaves of Frnlla-
nia ; it answers exactly to the arrangement of the cells
in the direction of the surface, of young shoots of Pellia
(PI. VII, fig. 21).

The leaves of the Jungermanniae usually exhibit a very
decided inclination to development in breadth. I know
of no species in which a single apical cell divides by means
of septa spreading alternately right and left, and in which
the division lasts until the termination of the growth
of the leaf. The development of the leaves of all Jun-
germanniae agrees in this, that the leaf originates in the
extension outwards of one or more cells of the bounding
surface of the stem close underneath its growing apex,
and the subsequent separation by septa of the protuber-
ances thus formed from the original cell-cavity. This
first rudiment of the leaf grows at first exclusively by
division of the cells of its apex and edge. After a
series of such divisions, sometimes after very few (in ex-
treme cases, as in Fossombronia, and in Haplomitrium
according to Gottsche, after one single division) there en-

64 H0FME1STER, ON

sues a most active and long-continuing multiplication of
the cells of the base of the leaf, which gives the leaf its
final shape.

The leaf- development of the different Jungermanniae, which
I have endeavoured to describe in the preceding pages, may
be looked at from one and the same point of view. How-
ever different at first sight the individual processes may
appear, they may be looked upon collectively as a tendency
in the longitudinal halves of the young leaf-rudiments to
develope themselves independently, and often unequally.
The upper and lower lobe of the leaves of Scapania, Frulla-
nia, Radula, &c, answer to the two tips of the leaves of
Lophocoleae, Jung, bicuspidata, Ptilidium, and others.

The mode of ramification of the Jungermanniae is very
difficult to unravel, on account of the nature of the terminal
buds. I have not arrived at an entirely clear idea of it in
any species. Many observations point to the conclusion
that the normal ramification of the axis results from a
genuine furcate division of the naked apex of the terminal
bud above the place of origin of the youngest leaf {e.g., PI.
VII, fig. 1, Ptilidium ciliare), and there is nothing opposed
to this view. The cases which appear to contradict it (such
as the development of new shoots out of the axils of the
leaves of fruit-bearing, or even older branches of terrestrial
Jungermanniae), may be looked upon as the development
of adventitious buds.

These shoots in /. bicuspidata often attain the length of
several millimetres without producing leaves. They are,
therefore, just the objects in which the nature and method
of cell-multiplication in the apex of the stem of Jungermanniae
may be most conveniently investigated (PI. VIII, fig. 12 "* b).
The half- subterraneous shoots of HaptomitriumHookeri often
remain in like manner leafless for a considerable extent.
These are the processes which Gottsche is inclined to con-
sider as being true roots of this liverwort, which is entirely
unprovided with rootlets ('Nova Acta Acad. C. Leop.,' vol.
xx, 1, 275). I had the opportunity of convincing myself
that the structure of the growing end of these shoots en-
tirely coincides with that of the end of the stem (PI. VII,

THE HIGHER CRYPTOGAM IA. G5

fig. 1). They grow by continually repeated division of a
single apical cell by means of septa alternately inclined in
different directions. These shoots are also remarkable from
the fact that in the older portion of them each epidermal
cell grows out into a short papilla (PL VII, fig. 2), an en-
largement of the upper surface, which may serve as a
compensation for the absent rootlets.

The antheridia of the liverworts are mostly axile, some-
times solitary (Jungermannia, Lophocolea, Radula, Ma-
dotheca), sometimes gregarious (Alicularia, Prullania), in
the axil of the same leaf. They are only occasionally free,
i. e., not protected by covering leaves on the upper surface
of the stem (Fossombronia, Haplomitrium) . The formation
of the antheridium commences by the protrusion outwards
in the form of an arch, and to a considerable extent, of
one of the cells of the upper surface of the stem, before
the latter has ceased to grow in thickness, and by the sepa-
ration, by means of a transverse septum, of the protu-
berance thus formed from the original cell cavity. In the
cell thus formed, which protrudes above the surface of the
stem, there sometimes commences a series of repeated
divisions of the apical cell by septa alternately inclined in
two directions {Madotheoa platyphylla, Fossombronia pu-
silla). This series of divisions, however, is not of frequent
occurrence. More frequently the primary cell of the
antheridium is divided several times successively by septa
parallel to one another. By this means it is transformed
into a row of cylindrical cells, which is sometimes of con-
siderable length, as in Lophocolea heteropltylla. The ter-
minal cell of this cellular thread swells in a clavate manner
(PL XI, fig. 39). It divides by a septum diverging from
its longitudinal axis ; the upper one of the newly formed
cells then divides by a septum inclined in the opposite
direction. The cells of the second degree are divided by
radial longitudinal septa ; one of the cells of that upper
pair of cells of the third degree which is nearer the apex of
the antheridium, divides by a septum parallel to the longi-
tudinal axis, and cutting the side walls of the mother-cell
at an angle of 45°. The young antheridium now consists
of a spherical group of cells — a central cell surrounded by

5

66 HOFMKISTKR, ON

five cells — which is borne by an elongated cylindrical
stem consisting of a single row of cells (PI. XI, fig. 1, 40).

The cells of the latter continue to divide frequently by
septa parallel to those already present. The central cell
of the spherical head which it supports multiplies actively
in all three directions by repeated bisections (PI. IX, fig.
31 ; PI. XI, figs. 2, 41), whilst the cells of its outer layer
divide only by septa at right angles to the outer surface, and
much less frequently than the central cell. The anthe-
ridium is now a spherical mass of small cells filled with
mucilage, surrounded by a single layer of tabular cells con-
taining chlorophyll (PL XI, "fig. 3). In each of those
smaller cells a spermatozoon is formed inside an ellipsoidal
or spherical vesicle (PI. VII, fig. 6; PI. XI, fig. 42).
When the antheridium is ripe, the cells of its outer layer*
separate from one another (PI. VI, fig. 37 ; PI. XI, fig. 42) ;
the vesicles containing the spermatozoa, which have become
free by the dissolution of the walls of the cellules containing
them, escape in the form of a mucilaginous mass. They
disperse themselves under water, and commence a rotating
motion. The wall of the vesicle bursts, the enclosed
spermatozoon escapes either wholly or partially (PI. XI,
fig. 42), and moves about in the water, keeping up a per-
petual rotation round the axis of the spiral which it pre-
sents (PI. VII, fig. 12; PI. VIII, fig. 3).

In the antheridia of those species in which division by
alternately inclined septa commences even in the earliest
primary cell of the antheridium, the essential parts, i. e., the
mother-cells of the first degree of the spermatozoa and
their covering layer, are developed in a precisely similar
manner. A long series of cells of the second degree fail to
multiply, so that a cylindrical double row of cells (long in
Madotheca, short in Fossombronia) represents the second
stage of development of the antheridium. The free end of
this cylinder swells up to a clavate shape ; and in the two
youngest cells the divisions now ensue which lead to the
formation of the central cell and its covering layer.

* In some species (e. g., Fosssombrouia pusilla) the granules of chlorophyll in
these cells have by this time become yellow, as is the case in Anthoceros, and
in the mosses.

THE HIGHER CRYPTOGAMIA. 67

Madotheca platypJiylla exhibits a remarkable peculiarity.
The cells of the covering layer not only divide very fre-
quently by septa perpendicular to the outer surface, so that
they appear proportionally small and very numerous in
the perfect antheridium ; but the lateral cells and those
underneath the central cell divide also by septa parallel
to the outer surface of the young antheridium ; the
upper ones once, the lower ones several times over.
By this means the antheridium acquires a consider-
able size; the oval group of cells in which the sperm-
atozoa are produced occupies only a small portion of its
upper half. The covering of this group of cells consists
also always of a single layer of cells (PL VII, fig. 5). The
walls of the cells of the covering-layer are coloured a bluish-
red by iodine.

The spermatozoa in the leafy JungermanniaD are con-
siderably smaller than those of Pellia. Fossombronia
pusilla has the largest of all those which I have examined ;
the diameter of the vesicles in which they originate is
~" ; those of the diminutive Jangermannia divaricata
are a little smaller (PI. VII, fig. 21) ; those of Frullania
dilatata and Madotheca platypliylla are very small (PI. VII,
fig. 6; PL XI, fig. 42).

The development of the archegonia of the leafy liver-
worts corresponds exactly with that of the like organs in
Pellia, the Marchantia?, and the mosses. In Fossombronia
and Haplomitrium these organs are produced in the axils of
leaves ; in the other genera treated of in this chapter they
are found only on short lateral branchlets. In growing
archegonia, however, the peculiar condition which occurs
in Pellia and the mosses is seldom seen. In Pellia and
the mosses it often happens that the formation of the cells
of the axile string does not extend as far as the cells im-
mediately adjoining the apical cell, a fact which is doubt-
less to be attributed to the slow, and consequently relatively
limited development of the neck of the organ. The arche-
gonia of the true Jungermannise, and of Badula complanata,
are proportionately short and uniformly thick (PL VII,
figs. 14, 15 ; PL VIII, figs. 1, 2 ; PL X, fig. 1 ; PL XI,
fig. 1) ; those of Fossombronia (PL VI, figs. 29—33)

68 HOFMEISTER, ON

and of Frullania are remarkably distended at the place
where the large cell at the base of the neck is enclosed ;
those of Frullania have a longer neck than any moss or
liverwort, without exception, with which I am acquainted
(PI. XII, figs. 1, 3).

With a few exceptions peculiar to the Jungermannise
proper (PL VII, fig. 15; PL VIII, fig. 2 ; PL X, fig. 1),
the archegonia of the leafy liverworts agree in the fact that
until the formation of the rudiments of the fruit, the mother-
cell of the large cell at the apex of the distended portion,
is enclosed only by a single layer of cells ; and they also
agree in the fact that the distended portion is only of
moderate height, and that before impregnation only two or
three, or at the most four cells, are to be counted between
the lower arched surface of the above-mentioned large cell
and the base of the archegonium.

The archegonia of the greater number of leafy liverworts
are furnished with a peculiar cup or pitcher-shaped organ
of later growth than the archegonium itself — the calyx or
pericmthium of authors. In all cases which have been
observed, the first appearance of this organ is in the form
of a closed ring, consisting of a single layer of cells.

This is the case in the very different perianths of
Frullania and Raclula, and of Jimgermannia bicuspidata
and divaricata. The first rudiment of the perianth is
formed by a contemporaneous protrusion, outwards and
upwards, of a belt of cells belonging to the apex of the
stem, surrounding the archegonia; and by the separation of
the protruding portion of the cells, from the portion lying
within the body of the stem, by means of a transverse
septum. The like form of division is repeated several
times in the coronet of apical cells of the young organ. In
Badtda complanata it lasts until the perianth has completed
the full number of its cells in the direction of its length.
Here and there cells belonging to the margin are also at
the same time divided by vertical septa, and thus the
number of cells of the circumference is increased above
(PL XI, fig. 1). The form of the perfect perianth of
Radula is consequently that of a horn continually
widening upwards, and closely compressed laterally ; doubt-

THE HIGHER CRYPTOGAMIA. C9

less the result of the resistance of the almost contiguous
fore and hind lobes of the enveloping leaves, between which
the organ must develope itself.

A very different state of things is presented in Junger-
mannia bicuspidata and divaricata, and in Frullania dilatata.
In these plants, and in the latter of them at a very early
period, the multiplication of the cells of the free upper
edge of the perianth ceases altogether. On the other hand
there ensues an active multiplication of the basal cells by
rapid and often repeated divisions, in Jiingermannia divari-
cata and cuspidata chiefly by horizontal septa, in Frullania
almost as vigorously by vertical septa (PL VII, fig. 14 ;
PI. VIII, figs. 1,2; PI. XII, fig. 2). The cells of the free
edge of the perianth of Jiingermannia bicuspidata grow at an
early period into long teeth, with transparent contents and
thick cell-walls (PI. VIII, figs. 1, 2). The form of the organ
passes from that of an open basket into a cylindrical, and
thence into a clavate shape ; the converging teeth close the
opening over the half-ripe fruit. In Frullania dilatata the
perianth during development becomes more and more
distended (PI. XII, figs. 1, 2). The mouth, a narrow
ring, is lifted up higher and higher, reaches the height of
the apex of the archegonium shortly after the completion of
impregnation (PL XII, fig. 3), and by the time of the
termination of the longitudinal growth of the perianth, is
carried about five times higher, by the continuous multi-
plication, and ultimately extensive expansion of the cells of
the base. At the time of the ripening of the fruit the
number of the cells of the free edge of the narrow mouth
of the perianth is not greater by one than at the first
appearance of the perianth out of the surface of the stem
beneath the archegonia, when it amounts to from sixteen to
twenty. In Alicularia scalaris the intercalary cell-multi-
plication extends from the basal cells of the perianth,
up to the tissue of the end of the stem which bears the
archegonia. At the time when the rudiments of the
perianth appear in the form of an annular border enclosing
the young archegonia, the end of the stem is slightlv
convex.* During the growth of the perianth there ensues

* See Gottsclie, 1. c., p. 325.

70 HOFMEISTEB, ON

an active multiplication in the direction of their growth
(outwards and at the same time obliquely upwards) of the
peripheral layers of cellular tissue of the apex of the stem.
This multiplication extends downwards from the rudiments
of the perianth to the second or third pair of leaves. By
this process the end of the stem which bears the archegonia
becomes depressed below the level of an annular wall-
shaped enlargement of the cortex of the stem, which
enlargement bears upon its upper margin the young
perianth, and upon its outer surface the uppermost pair of
stem-leaves. An expansion of the cells of the above
enlargement, in a direction parallel to the longitudinal
axis of the stem, ultimately raises the points of insertion of
the upper leaves above the apex of the calyptra.

From an exaggeration of the same condition is produced
the peculiar formation of the (abnormal) perianth of Calypo-
c/eia Trichomanes. Gottsche has shown* that the short
few-leaved branch which springs laterally from the median
line of an inferior leaf, bears upon its apex the archegonia
which are immediately surrounded by the last leaves ; the
apex of this branch inclines upwards, and becomes a round
fleshy knob.f Successful longitudinal sections perpendicular
to the plane in which the surfaces of the leaves of the prin-
cipal axis lie, and passing through this axis, and also through
the young fruit-branch which lies laterally in the axil of one
of its inferior leaves, proved to me that the latter branch,
which at first is directed obliquely downwards, curves itself
upwards, so that at the period of impregnation the arche-
gonia are erect (PI. X, fig. 1). The central cell before
impregnation is exceedingly small. The completion of the
impregnation is first recognisable by an unusually active
multiplication of the cells of the central portion of the
archegonium during its conversion into the calyptra ; a
multiplication which forthwith commences in the tissue of
the fruit-branch immediately adjoining the base of the
archegonium (PI. X, fig. 1). The small-celled tissue thus
formed, which bears the impregnated and the abortive
archegonia, becomes developed into the fruit-sac. The

* ( Nova Acta Ac. C. L.,' xxi, p. 427.
f L.c, p. 438.

THE HIGHER CRYPTOGAMTA. 71

larger wide-celled moiety of the fruit-stalk above the former
takes no part in this new formation. An active cell-
multiplication continues to take place in the former tissue
for a long time. In the cells undergoing division, transverse
septa perpendicular to the convex outer surface of the fruit
branch often make their appearance. The annular zone of
new cells thus formed, which lies at the greatest distance
from the archegonia, undergoes, immediately after its forma-
tion, a considerable longitudinal elongation, at right angles
to the partition-walls by the formation of which the cells
were individualised. This is the mode in which the end of
the fruit-branch", which is originally cushion-shaped, becomes
transformed into a pitcher-shaped organ (PI. X, fig. 6).*
The cells of the inner surface of its cavity are from four to
eight times narrower than those adjoining them. This
arises from a division of the cells of the inner surface, by
means of longitudinal and transverse septa perpendicular to
the free surface, which takes place after the last division of
the cells adjoining them. These narrower cells expand into
long papillae directed rectangularly inwards, which almost
entirely fill the cavity of the fruit-sac (PL X, figs. 6, 8).t

Shortly before the commencement of the dissolution of
the transverse septa of the string of cells which occupies
the longitudinal axis of the neck of the archegonium of
Fossombronia pusilla, a small free cell becomes visible in
the middle cell of the ventral portion of the archegonium,
occupying about an eighth part of the cavity of the latter
cell, and near its very distinct primary central nucleus.
The contents of this small free cell are transparent, and it
has a finely granular nucleus with no nucleolus. There
can be no doubt that this cell originates in free-cell forma-
tion round a secondary nucleus. In archegonia a little
more developed, this cell, which has considerably increased
in size, quite fills the lower third-part of its mother- cell. The

* It is essentially the same process which makes the cavity of the ovary of
epigynous Phaneiogamia inferior, and by which the nucleus of many anatropal
ovules which have massive outer integuments, becomes sunk within the integu-
ments, except that in these cases, and especially in the latter, cell-formation
and cell-expansion are not so clearly distinguishable from one another as iu
Calypogeia.

f Gottsche has given an elegant figure of a longitudinal section of a later
condition of the fruit-sac, 1. c, T. xxxi, f. 15.

72

HOFMEISTER, ON

primary nucleus of this latter cell has become indistinct, in
fact hardly discernible ; it is manifestly undergoing dissolu-
tion (PI. VI, fig. 32). As soon as the canal which trans-
verses the neck of the archegonium is completely formed
by the dissolution of the transverse septa of the axile row
of cells, no trace of the primary nucleus of the central cell
is any longer perceptible. The free daughter-cell, the
germinal vesicle, now occupies about two third parts of the
central cell (PI. VI, fig. 33).*

In those forms where the central cell of the archegonium
is smaller, the germinal vesicle at the time of the opening of
the apex of the archegonium, almost entirely fills the mother-
cell (PL VII, figs. 15, 16; PI. VIII, fig. 2; PL XII, fig. 1).

Most archegonia are not developed beyond this stage.
The cell-walls, which adjoin the longitudinal canal of the
neck, assume a chestnut-brown colour, as also the inner wall
of the large central cell of the ventral portion. The spheri-
cal cell, which has originated in the latter, becomes trans-
formed into a dark brown mass. In individual archegonia,
however, seldom in more than one in the same inflorescence,
a fruit is produced by continuous division of the spherical
cell which has been formed within the central cell of the ven-
tral portion. It is more than probable that the action
upon the archegonium of the spermatozoa, emitted from
the antheridia of the same species, is necessary in order to
bring about the development of the rudiments of fruit.
Where antheridium-bearing plants are found in the
neighbourhood of those bearing archegonia, much fruit is
met with ; when the contrary is the case there is no fruit.
The common Lophocolea bidentata is a remarkable instance ;
this plant usually has abundance of archegonia, but very
seldom bears antheridia, and the fruit is proportionately
rare.

Those species fructify the most abundantly which bear

* The nucleus of the germinal vesicle very much resembles the defunct
primary nucleus of the central cell. This circumstance, and the rapidity with
which the above-mentioned process of development is gone through, led me on
a former occasion (' Vergleichende Untersuchungen,' pp. 37, 47,^67,) to look
upon the nucleus of the germinal vesicle as identical with that of the central
cell, and to assume that the formation of the germinal vesicle took place by
means of free cell-formation round the primary laicleus of the central cell.

THE HIGHER CRYPTOGAMIA. 73

antheridia in the axils of the leaves of the shoot which has
archegonia at its apex. This is the case with Lophocolea
heterophylla and Radula complanata, and frequently, but
not always, with Jungermannia divaricata, all of which are
nearly allied to Lophocolea bidentata. Frullania dilatata,
a very free-fruiting species, certainly does not very often
produce antheridia. Here, however, the mode of growth
of the plant, is such as greatly to facilitate the passage of
the contents of the antheridia to the archegonia. The
patches of Frullania, which are in a dry situation, and at
some height from the bottom of the tree on which they
grow, are those which especially produce antheridia. When-
ever rain falls, or there is a heavy dew, a considerable
quantity of water trickles down from the patches which
bear the antheridia, to those beneath them in which the
archegonia occur. Moreover, the quantity of fruit in Frul-
lania, however abundant it may be, is not at all proportion-
ate to the enormous number of archegonial branches which
the plant produces. The greater number of the hWers
(which only contain two or three archegonia) are abortive,
and produce no fruit.

The structure of the perianth of the Jungermanniae is no
obstacle to the impregnation. In Radula, in Frullania, even
in the Lejeuniae, the development of the rudiments of the
fruit commences before the margin of the' perianth is raised
above the apex of the archegonia. In Jungermannia bicus-
pidata also the development of the fruit often begins very
early, when the perianth has still the form of a wide open
basket (PI. VI LI, fig. 3), but often also (as is the case too
with /. divaricata) at a considerably later period, when the
perianth has assumed the form of a hollow cylinder, when
its margin begins to become folded and to bend inwards.
These instances, however, are just those which afford un-
doubted proof that even under unfavorable circumstances
the spermatozoa can reach the antheridia. In perianths of
both species which I have cut open longitudinally and
placed quickly in water, I have several times most clearly
seen spermatozoa in rapid motion, whirling actively around
the archegonia (PI. VIII, fig. 12). In the Jungermanniae
there is found at the aperture of all archegonia which have

74 HOFMEISTER, ON

recently opened, small globular drops, often in large quan-
tities, consisting of a hyaline transparent slimy substance.
They appear to be formed from the escaped contents of the
canal which traverses the neck of the archegonium. In
recently-opened archegonia of /. bicuspidata and /. divari-
cata, as well as of J. bicrenata and Alicularia scalaris
(which archegonia by the commencement of the swelling of
their ventral portion exhibited the first indication of the
fruit-formation), I saw between these drops, delicate, more
or less twisted, colourless filaments, in appearance and size
exactly similar to the spermatozoa of those species, but
motionless (PL VII, figs. 12, 17 ; PI. VIII, fig. 3).

The first division of the mother-cell of the rudiment of
a fruit takes place by a transverse septum, at right angles
to the longitudinal axis of the archegonium, and to that of the
future fruit (PL VII, figs. 12, 17; PL VIII, fig. 3; Pl.X, fig. 1;
PL XI I, fig. 3). In Frullania dilatata and Calypogeia Tricho-
manes the youngest, bicellular condition of the fruit is
shortly oval ; in Jung, divaricata it is somewhat more elon-
gated, and in J. bicuspidata it is drawn out to a great
length. The lower of the newly-formed cells continues
(with rare exceptions) during the whole life of the fruit
without division ; the upper one divides either immediately
by a longitudinal septum (as is almost always the case in
Frullania dilatata, Zopl/ocolea heteropliylla, liadula compla-
nata, and Alicularia scalaris), or else it divides once or
several times by horizontal transverse septa (as in /. bicus-
pidata, PL VIII, figs. 4, 5, J. divaricata, PL VII, fig. 8) ;
the division by a longitudinal septum first occurs in the
apical cell of the very young rudimentary fruit which con-
sists of a single row of from three to five cells.

A horizontal transverse septum is now formed in both the
newly formed apical cells; each divides into an upper cell, hav-
ing the form of a quadrant of a sphere, and a lower cylindrical
one. A longitudinal septum bisecting the cell and radial to
the axis of the young fruit is then formed in each of the apical
cells, so that the rudimentary fruit now exhibits four apical
cells. In Frullania this division commences normally in the
pair of cells nearest to the basal cell (PL XII, figs. 6, 7).
In Calypogeia the same phenomenon is frequent (PL X,

THE HIGHER CRYPTOGAMIA. 75

figs. 2, 4) but not normal (PI. X, fig. 3). Henceforth, the
number of the cells of the rudimentary fruit, in the direc-
tion of the longitudinal axis, is increased ; at first exclu-
sively by repeated contemporaneous division of its four apical
cells by means of horizontal transverse septa at right
angles to the axis of the fruit.

This kind of cell-multiplication shows itself in the
most simple form in the few-celled rudimentary fruit
of J, divaricata. Its apical cells contain colourless muci-
lage, rendered turbid by numerous large and small gra-
nules ; the interstitial cells are coloured deep grey-green
by numerous small chlorophyll-granules (PI. VII, figs.
13, 19). After the transverse division of the four apical
cells has been repeated eight or ten times, the longi-
tudinal growth of the fruit is completed (PI. VII, fig. 20).
The double pair of cells which now forms the apex of the
clavate rudimentary fruit, then remains for the first time
unaltered ; the three next, on the other hand, divide into
inner and outer ones by means of septa parallel to the lon-
gitudinal axis of the fruit, and cutting the side walls at
an angle of 45° (PI. VII, fig. 20). The outer cells become
the wall of the capsule ; further divisions take place in
each of them by means of longitudinal and transverse septa
perpendicular to the free outer surface. The wall of the
capsule shortly before it bursts usually has twenty-four cells
in its circumference, and eight cells in its height ; the cells
being of an oblong tabular shape. By a series of divisions,
occurring principally in radial and tangential directions,
the inner cells become transformed, partly into rows of
mother-cells, and partly into elaters. The elaters in
/. divaricata, as in all true Jungermannise and also in
Padula, extend horizontally from the inner wall of the
capsule to the longitudinal axis. In all these the inner
tissue of the capsule, from which the spores and elaters
are formed, consists, from the moment of the differentia-
tion of the capsule-wall from its contents, of a short slightly
distended columella, formed of a double pair of cells, with
a quadrantal basal outline (PI. XI, fig. 6). The first divi-
sions of the latter cells take place by septa perpendicular
to the longitudinal axis of the fruit alternating with others

76 HOFMEISTUR, ON

radial to it. In the cells destined to form elaters no
transverse septa are formed, whilst their sister-cells by
repeated division parallel to the axis of the fruit form rows
of cubical cells — the spore-mother- cells. These are, there-
fore, arranged in rows, which radiate horizontally from
the longitudinal axis of the capsule, each three of which are
succeeded by an elater, and of which four (sometimes by
displacement, as many as eight), are contiguous to each elater
(PI. VIII, fig. 7 ; PL IX, fig. 23).

Contemporaneously with the commencement of the dif-
ferentiation of the capsule-wall of /. divaricata from its
contents, (which takes place by division into outer and
inner ones of three double pairs of cells of the upper
clavate portion of the rudimentary fruit,) septa parallel to
the axis of the fruit are also formed in the first and second
double pairs of cells above the base of the young fruit ;
the outer ones of the new cells thus formed divide by
radial longitudinal septa. As they expand considerably in
breadth, and protrude arcuately outwards, they form the
knobby protuberance by which the fruit is attached to
the tissue of the stein which bears it (PI. VII, fig. 20).
The basal-cell and the pair of cells above it remain un-
changed. On the other hand, the cells of that portion of
the rudimentary fruit which lies between the basal en-
largement and the bottom of the capsule, — i. e., the fruit-
stalk, — divide all together by horizontal septa. They thus
represent quadrants of cylinders of very small height ; the
transverse diameter is from six to eight times greater than
the altitude. A sudden longitudinal prolongation of these
cells, to an extent manifestly far exceeding fifty times
the original longitudinal diameter of the cells, lifts the
capsule up (when the fruit is ripe), through the fissure of
the ruptured calyptra, high above the perianth. 1 have
found no trace of a flow of sap into the cells of the fruit-
stalk in this species, although it is certainly the one best
suited for such an observation.

The development of the fruit of the greater number
of the Jungermanniae agrees very closely with that of
J. divaricata, and differs only by the more frequent repeti-
tion of certain cell- divisions, and by more vigorous develop-

THE HIGHER CRYPTOGAMIA. 77

raent in length and thickness. In /. bicuspidata (PL VIII,
figs. 5, 7), and /. tricophylla, in Radula complanata (PL XI,
figs. 4, 5), Lophocolea heteropkylla, Alicularia scalaris, and
Ccdypogeia Trichomanes (PL X, figs. 2-8), the four apical
cells of the rudimentary fruit often divide repeatedly by
horizontal transverse septa; the three-sided cells of the
second degree thus formed divide, however, all together,
by septa parallel to the tangent of the curved outer-wall,
and cutting; the side- walls at an angle of 45°. In J. bicus-

i •

pidata (PL VIII, fig. 7), this division takes place once, in
Lophocolea heteropkylla, and Radula complanata twice (PL
XI, figs. 4, 5) ; in the latter by a repetition of the division
in the outer cells, after a previous formation of radial
longitudinal septa therein. After the cesser of multiplica-
tion in the apical cells, the capsule-wall is produced by the
continuous division of the outer layer (in Lophocolea, Radula,
and Alicularia, of the two outer layers) of cells of the
rudimentary fruit ; by the multiplication of the elongated
axile group of cells, formed out of four longitudinal rows of
three-sided cells, are produced the elaters, which radiate
from the longitudinal axis of the fruit to the capsule-wall,
as well as the rows of spore-mother-cells, which are inserted
between these in horizontal rows. The cells of the middle
part of the rudimentary fruit assume a depressed tabular
shape by repeated transverse divisions ; collectively they
form the fruit-stalk. In Jungermannia bicuspidata and
tricophjlla, the fruit-stalk normally consists of twelve longi-
tudinai rows of cells, of four strings of three- sided cells
traversing the interior of the stalk, and a layer of eight
cells surrounding these standing at an equal elevation. In
the cells of the outer layer transverse division ensues to a
greater extent than in those of the central string ; the latter
are double the height of the former (PL VIII, fig. 7 ; PL
IX, fig. 23) .The fruit-stalk of Lophocolea, Radula, Alicu-
laria, and Calypogeia (PL X, fig. 7), which, after the dif-
ferentiation of the capsule-wall from its contents, consists
of three concentrical layers of cells, continues to grow in
thickness up to this period ; in Radula the growth takes
place by a single division ; in Lophocolea and Alicularia
by repeated divisions of the cells of its circumference.

78 HOFMEISTER, ON

By cell-multiplication extending on all sides, and dimi-
nishing downwards, the base of the rudimentary fruit be-
comes transformed into a turnip-shaped enlargement, sunk
into the tissue of the fruit-bearing shoot. This enlargement
is most vigorously and peculiarly developed (as is known
from Gottsche's beautiful observations, ' N. A. A. C. L.'
vol. xxi, p. 2) in the Geocalycese, where its upper margin
grows into the sheath surrounding the fruit-stalk ; and in
Calypogeia, where it grows into a highly delicate membrane.
A similar appearance is presented in Alicularia scalaris,
which, in the formation of its perianth, in some respects
resembles the Geocalycese : here four triangular fleshy lobes
which surround the base of the fruit-stalk, are developed out
of the enlargement of the lower end of the rudimentary fruit
(PL VII, fig. 10). These are less conspicuous in the true Jun-
germannige, and in Lophocolea. Fridlania dilatata exhibits
hardly any indication of them (PI. XII, fig. 9) ; lastly, in
Radula complanata there is only a very moderate enlarge-
ment of the lower end of the fruit-stalk, produced by a
transverse stretching and papillate expansion of the cells of
its outer surface (PI. XI, fig. 7).

The development of the fruit of Fridlania dilatata (and
doubtless also that of the nearly-allied Lejeuniae) differs in
its middle stages not immaterially from that of the proper
Jungermanniae. In Fridlania the four apical cells of the
rudimentary fruit divide, even at an early period, by means
of longitudinal septa, which form an angle of 45° with the
side- walls, but diverge at a sharp angle from the longitu-
dinal axis of the fruit. The division of the apical cells
afterwards proceeds in the same manner as in Pellia and
Aneura. In the mean time the lower part of the rudi-
mentary fruit increases considerablv in thickness ; the cells
of its circumference divide repeatedly by longitudinal septa
parallel to the axis, alternating with radial septa. The
form of the rudimentary fruit is far less slender, its apex is
proportionately far wider, than in /. bicuspidata or Radula
complanata (PI. XII, fig. 8). The elaters and the spore-
mother-cells are produced by the multiplication of a hori-
zontal stratum of cells, which is separated by a double
layer above it from the cells of the apex of the rudimentary

THE HIGHER CRYPTOGAMIA. 79

fruit. This production takes place after the multiplication
of the apical cells of the young fruit in a longitudinal
direction lias terminated (PI. XII, fig. 8). The two
covering layers of cells form the capsnle-wall, having first
multiplied considerably by often repeated longitudinal and
transverse divisions which take place by septa perpendicular
to the outer surface. The capsule-wall, in consequence of
the rapid increase of the number of its cells, eventually
becomes hemispherical (PI. XII, fig. 9). Most of the
somewhat elongated cells of the horizontal cellular surface,
enclosed by the capsule-wall, follow the progress of the
latter as its arched surface becomes elevated, dividing
repeatedly by transverse septa ; some, however, expand
only in a longitudinal direction until they eventually assume
the form of narrow cylindrical tubes, parallel to the longi-
tudinal axis of the fruit. These tubes are attached at the
base to the upper end of the fruit-stalk, and at their apices
touch the inner arch of the capsule-wall (PL XII, fig. 9).
The latter are the elaters ; the tessellated cells produced
by the division of the elongated cells, become the spore-
mother-cells.

Contemporaneously with the earliest period of the de-
velopment of the rudimentary fruit of liverworts, there
commences a very active multiplication of the peripheral
cells of the ventral portion of the archegonium, which thus
becomes the calyptra. The cell-division, which occurs
repeatedly and in rapid succession, often extends far down-
wards into the tissue of the branch which bears the im-
pregnated archegonium. Whilst the lower part of the
archegonium becomes transformed into the upper half of
the calyptra, its distended form becomes compannulate
(/. bicuspidata, PI. VIII, fig. 6 ; Badula complanata,
PI. XI, fig. 4). The lower portion of the calyptra is
formed out of the upward- growing tissue of the tip of the
shoot upon the apex of which the archegonia stand. The
abortive archegonia often appear pushed up high on the
side-walls of the calyptra, wrhich has originated from the
impregnated archegonia (PI. XI, fig. 4, Badula com-
planata).

No distinction can be traced between the base of the

80 HOFMEISTER, ON

calyptra in many liverworts (which is produced by the
multiplication of the cells of the apex of the stem), and the
vaginula of the mosses. In Badula complanata, for in-
stance, the base of the calyptra is not less remarkably
conical and fleshy than in Phascum. This multiplication
of the cells underneath the impregnated archegonium in
the direction of their thickness, is very active in Badula
complanata, less so in Lophocolea and the true Junger-
mannige ; lastly, in Frullania dilataia it is entirely
wanting ; here the multiplication of the cells is limited
exclusively to the ventral portion of the impregnated arche-
gonium, towards the base of which it diminishes con-
siderably. The form of the calyptra in this species is
flask-shaped in all stages of its growth; it is narrowly
constricted at the base (PI. XII, figs. 3, 5).

The lower, reduced end of the rudimentary fruit, extends
downwards to the same distance as the cell-multiplication
beneath the impregnated archegonium extends upwards
into the tissue of the stem (PI. VIII, fig. 6 ; PL XI, fig. 4).
The arch of the basal cell of the end of the stem often
exhibits a marked thickening of its wall (PI. VIII, figs.
4, 5) ; perhaps it is by means of this that it acquires
sufficient firmness to penetrate the cells of the yielding
tissue which lies in its way. In Frullania dilaiata the
cavity of the calyptra, which encloses the young rudi-
mentary fruit enlarges soon after impregnation by a mul-
tiplication of the cells of its walls, often so rapid and con-
siderable, that the growth of the rudimentary fruit cannot
keep pace with the increase in circumference and height of
the cavity, which is filled with mucilage ; at this period
the young fruit often lies quite free in the interior (PL XII,

% 4)- . .

Gottsche observes a similar phenomenon in Cahjpogeia

Trichomanes* I have convinced myself by an observation
made in 1853, that in Calypogeia, also, the development of
the impregnated germinal vesicle normally follows step by
step the great enlargement of the central cell of the arche-
gonium, which is produced by the multiplication of its
neighbouring cells. Both developments are slow, that of the

* L. c, T. xxx, f. 8, 11.

THE HIGHER CRYPTOGAMIA. 81

germinal vesicle into the fruit the slowest. After the
completion of the rudiments of the fruit-sac, the calyptra
has only increased moderately in size, and the impregnated
germinal vesicle is still undivided, although doubled in
length. In the fruit-sac, when from I to 3 mm. long, the
rudimentary fruit is only 4-8 cellular (PI. X, fig. 8). At
all stages of development it entirely fills the cavity of the
calyptra. The condition figured by Gottsche is certainly a
diseased one ; the rudimentary fruit, developing itself feebly,
could not follow the growth of the walls of the archegonium.

In certain Muscineae {Pellia epiphylla, Jung, divaricata,
Phascum cuspidatum), and also in some vascular cryptogams
{Pteris aquilina, Aspidium Filix-mas, and Salvinia nutans),
where several archegonia of one and the same group have
been impregnated, the less developed of these archegonia
have afforded me similar cases decisive of the point that
the increase in size, and the form of the growing base of
the archegonium, is not produced by the contact of the
rudimentary fruit or of the embryo. In all these cases,
moreover, two archegonia of the same prothallium had been
impregnated ; the arrest of development of the embryo had
occurred in the less-perfect archegonium, which had
manifestly been the latest impregnated and insufficiently
nourished.

In the leafy as well as in the leafless Jungermanniae the
individualization of the elaters and spore-mother-cells is
preceded by a considerable thickening of their walls, and
the conversion of the substance of these walls into a mate-
rial which swells up extensively in water. The mass of the
thickened cell-walls often swells up in water more rapidly
and to a greater extent than even in Pellia ; in J. bicuspidata,
Badula complanata, and Frullania dilatata, the determina-
tion of the arrangement of the cells of the interior of the
young capsule is thereby rendered extremely difficult. In
all the species which I have examined the substance of the
walls, when moistened with tincture of iodine, became
quite blue. In the mother-cells of the large-spored Frulla-
nia dilatata four protrusions of the wall (quite similar
to those of Pellia, before mentioned,) and the gradual
increase in size of the inner wall of the superimposed

6

82 HOFMEISTER, ON

ridges, which by their ultimate confluence become the
septa of the special mother-cells, are clearly perceptible
(PL XII, fig. 10). These special-mother-cells in Frullania
dilatata exhibit delicate pits (Tiipfel) similar to those of
Anthoceros jmnctatus.

The wall of the half-ripe capsule of most Jungermanniae
consists of a double layer of cells {J. bicuspidata, triclio-
<phyllai Frullania dilatata, Radula complanatd). As the fruit
approaches maturity the inner of these cellular layers is
usually dissolved, and displaced by the growing spores.

The individualization of the cells of the interior of the cap-
sule depends, as in all similar cases, upon a highly advanced
state of this change in the properties of the substance of the
wall of the outer layer of the affected cell-membrane. There
exists, however, a striking difference between what occurs in
Jungermanniae, and the analogous processes in the develop-
ment of the spores of other mosses and vascular crypto-
gams, and of the pollen-cells of Phanerogamia. In
Jungermanniae a thick layer, constituting almost the
entire mass of the cell - membrane, undergoes trans-
formation into a substance which becomes distended
in water into a gelatinous mass, and disperses itself
through the fluid; -whilst in other cases this modifica-
tion of the cell-membrane is limited to an immeasurably
thin external layer. In many cases, even in Jungermanniae,
the condition of the different layers of the mother-cell-
membrane during the distension varies. In Fossombronia
pusilla the inner layer of the wall of those cells which are
exclusively developed into elaters is so vastly distended by
water wThen in a young state, that it bursts the outer layer
of the cell-membrane (PL VI, fig. 36). The same state of
circumstances, somewhat modified, occurs in the mother-
cells of the same plant, where, however, the less-distendible
outer layer is so thick that it does not burst ; the expansion
of the inner layer takes place at the expense of the volume
of the cell- contents, which are compressed into a smaller
space (PL VI, fig. 35). In Blasia pusilla also the mem-
brane of the cell, from the division of which two spore-
mother-cells have arisen, and which is very often present
after the formation of the tertiary nucleus, resists the action

THE HIGHER CRYPTOGAMIA. 83

of water more than the membrane of the spore-mother-
cells themselves (PI. VI, fig. 23). The mother-cells of the
spores of all the true Jimgermanniae which I have examined,
those of Radula and Frullania, are rich in chlorophyll-gra-
nules. In Blasia pusilla the presence of chlorophyll is
limited to the tertiary nuclei destined for spore-forma-
tion, the substance of which seems usually to be coloured
green throughout (PI. V, fig. 24).

The first investigations into the germination of the spores
of Jimgermanniae, are those of Hedwig.* They extend no
further than the protrusion of the first rootlet. The observa-
tions published by Nees von Esenbeck,f do not advance
the knowledge of this subject to any further point. Bis-
choff, eighteen years later, \ directed attention to the
germination of Pellia, up to the formation of the first shoot. $
Bischoff's observations agree entirely with those of later
observers, even in the unimportant circumstance that he
represents the base of the germ-plant (the hinder part of
the multicellular spore) as a globular enlargement of too
great thickness. I have already spoken of the incorrectness
of the expression (Vorkeim) applied by Gottsche to the
first shoot of the germ-plant. Gottsche noticed, || although
not very clearly, the multicellular nature of the spores of
Pellia, and followed their germination, cell by cell, until the
perfect development of the first shoot, stating more intel-
ligibly the relation of the exosporium to the germ-plant.
Gottsche at the same time published an account of the
remarkable germination of Blasia pusilla ; he showed that
when the spore (after being sown) has become indistinctly
multicellular, a long, cylindrical, tubular cell shoots forth, the
end of which is developed into a cellular body, from which
at a later period the stem of the germ-plant is produced.
Lastly, Gottsche gave the first account of the germination

* ' Theoria generationis,' Leipz., 1798, 17.

+ ' Nova Acta,' A. C. L. N. C, xiii, 1 (1824), 165.

% 'Handb. bot. Terminologie,' Bil. ii, Nurnb., 1842, 733, t. lvii, 2795-96.
These observations appear to have been made as early as 1828. See 'Bot.
Zeit.,' 1853, 14.

§ Bischoff completed this work at a subsequent period by the publication of
further figures. See ' Bot. Zeit.,' 1853, t. ii, f. 14—21.

I| ' Nova Acta,' A. C. L., vol. xx, pars 1, 3S2.

81 HOFMEISTER, ON

of the spores of a leafy Jungermannia, /. crenulata*
That account does not extend beyond the formation of a
short filament from the inner spore-cell. After Gottsche's
observations no notices of the germination of Jungerman-
niae appeared until my own, mentioned above. At a later
period Gronlandf published his investigations of the germi-
nation of the leafy Jungermanniae. He showed that the
formation of the long, cylindrical tube discovered by
Gottsche in the germination of Blasia was suppressed in
cases where the spores were very thinly sown ; that under
these circumstances the spore immediately assumes the form
of a cellular body, similar to that which, when the spores
are sown thickly, originates in the end of each tube, j He
pointed out, moreover, the occasional ramification of the pro-
thallium of leafy Jungermanniae,§ and extended the obser-
vation to some species hitherto not investigated or only
imperfectly so — Sarcoscyphus Funkii, J. crenulata, and
Alicularia scalaris, the development of which in other
respects exhibits nothing peculiar.

The first important observations as to the mode of growth
and cell-multiplication of the ends of the stems of Junger-
manniae are those of Nageli. || He pointed out the mode
in which the terminal cell of the leafy axis of Metzgeria fur-
cata divides by alternating septa, directed obliquely right
and left perpendicular to the surface of the stem, and the
way in which the cells of the second degree thus formed
produce, by continued bisection, the entire mass of cellular
tissue of the flat stem. He showed further that the growth
of the stem which^[ is developed from the gemmae of J. ex-
secta, and that of the end of the stem of /. tricliophylla**
was produced by continual division of a single apical cell,
by means of oblique septa, of the same or a like inclination,
but differing in position. I have not obtained from my
own observations of the leafy Jungermanniae any ground of

* l. c, pp. 387, 391.
f 'Ann. d. Sc.,' iv ser., t. i, p. 1.
t I. c, p. 20.
§ I. c, p. 16.

j ' Zeitschrift f. wiss. Bot.'H. 2 Zurich, 1843, 138.
^j /. c, p. 166.
** /. c, p. 172.

THE HIGHER CRYPTOGAMIA. 85

support for Nageli's assumption that these septa are turned,
not in two opposite directions only, but in several direc-
tions.

With respect to the ramification of the Jungermanniae,
the books afford but little information. I find no mention
by any earlier observer of the difference, to which I have
called attention, between the true dichotomy of Metzgeria
and Aneura and the pseudo-dichotomy of Pellia. The re-
marks made by C. G. Nees v. Esenbeck, with respect to
the ramification of the Jungermanniae, have reference only
to the fully developed condition.* His statement that the
place of insertion of a branch in the principal axis is fre-
quently not determined by the position of the angle of the
leaf, in other words, that it is not found above the
median line of the next lower leaf, afford as much sup-
port to my conjecture that the normal ramification of the
leafy Jungermanniae is a true dichotomy, as does the
figure which Gottsche gives of a leafless subterraneous
shoot of Ilapiomitrium Hookeri divided into two branches
beneath the apex.f

With respect to the development of the leaves of Junger-
manniae, Gottsche's important statement must be remem-
bered, that in Haplomitrium Hookeri the leaf, when quite
young and consisting of only a few cells, bears at its apex
(or when mnlti-angular at each of its angles) a clavate, bent,
retort-shaped cell, which, in a fully developed leaf consisting
of a great number of cells, is still found in the corresponding
position. \ This observation, once made, afforded proof
that the cell-multiplication in the leaf of Jungermannia is
not the result of a continued multiplication of one apical

cell.

The knowledge of the structure of the archegonia of the
Jungermanniae was, like that of the similar organs in the
mosses, first established by Hedwig.§ He figures the arche-
gonia as organs closed before impregnation, as open at the

* ' Naturgeschichte Europ. Lebermoosc,' i (Breslau, 1833), 17.

f 'Nova Acta,' A. C L., xx, pars i, t, xiii, f. 1.

+ /. c, pp. 275, 276.

§ ' Theoria generationis,' Leipz., 1798, 164.

86 HOFMEISTER, ON

top at the time of impregnation, and then traversed in the
longitudinal axis by a canal ; as organs out of which at a later
period the calyptra, crowned with the neck of the archego-
nium, is developed. Our knowledge of the structure of
these organs had made no progress since the time of
Hedwig until my own observations were published.*

Prior to my own observations, the very young condition of
the fruit had only been seen by Gottsche twice in Calypo-
geia Tricliomanes, in the form of a two- or three-celled body at
the base of a wide cavity of the calyptra, and which Gottsche
considered to have sprung from the base of such cavity. f
At a somewhat later stage of development of the young
fruit, Gottsche saw indications of the formation of the same
out of four rows of cells trending downward to the one
basal cell, but he coidd not make out the matter clearly.
Schmidel had already observed the well-defined limits
between the lower end of the fruit-stalk and the tissue of
the stem into which that end is sunk ;f as also had Hedwig, §
who had observed the many toothed sheath around the
base of the fruit-stalk in Pellia epiphylla.

With respect to the development of the spores of the Jun-
germanniae, H. von Mohl established the fact that they are
formed in fours, in round mother-cells, and that the elaters,
as long as the spores are lying unformed in the mother-cell,
have the shape of spindle-like, delicate-walled cells, standing
in no organic connection with the spore-mother-cell. Von
Mohl also observed that the young oval spores of Pellia
epip/tylla, whilst still hanging together in fours, are only
in contact with one another by a small portion of their upper
surface. [|

The membrane of the perfect elater had been noticed by
Von Schmidel in Aneura multijida.% Nevertheless, the
notion of " naked elaters " was prevalent until a recent

* Compare C. G. Nees v. Esenbeck, 1. c, p. 60; Gottsche, 1. c, p. 315.
t ' Nova Acta/ Ac. C. L., xxi, pars ii, 445, 447.
X 'Icones plantarum,' iii, Erlaugen, 1797, Tf. 57, f. 14, J. exsecla.
§ ' Theoria generationis,' t. xvii, f. 10 ; /. nemorosa, t. xxiv, f. 4; xxv, f. 2,
Pellia epiphylla.

|| 'Mora,' 1S33. * Vermischte Schriften,' p. 68.
f ' Icon, plant.,' t. lv, f. 13.

THE HIGHER CRYPTOGAMIA. 87

period ; Gottsche first put a final end to it* by showing
the destructibility of this membrane by sulphuric acid, the
action of which was resisted by the substance of the spiral
thread. Gottsche showed also that the coloured thicken-
ings of the cell- membranes of the capsule-walls comport
themselves in this respect like the spiral thread of the
elaters, and by this discovery was in a position to give the
most satisfactory representations of the course of these
thickenings of the walls of the elater-cells and of the cells
of the capsule-wall. f

We are indebted to the same author for an explanation
of the development of the perianth of the Jungermanniae . He
showed j that the perianth in the Jungermannise is formed
in the same way as in Marchantia polymorpha, where it had
been observed by Hedwig§ and MirbelJ and where it
takes place at a late period, after the commencement of the
formation of the fruit ; he described the development of the
perianth of the principal types, and showed that the involucre
of Trichocolea is nothing more than the very fully developed
calyptra, similar to that of Aneura.

Schmidel's discovery of the self-motile bodies in the
antheridia of a cryptogamic plant was made in a Junger-
niannia, in Fossombronia pusilla.\ The attachment of the
antheridium to a stalk is first well figured by Hedwig in
the same plant.** The first figure of the spermatozoa of
a Jungermannia — Aneura pinguis — was given by Meyen.f f
The existence and nature of these bodies had in the mean
time been discovered in Sphagnum by Unger, and the
cilia by Thuret in Chara. Gottsche afterwards figured
those of Haplomitrium Hookeri, Alicularia scalaris, and
Fossombronia pusilla ;%% lately Thuret has given those of
Fellia epiphjlla and Fossombronia pusilla.^

* 'Nova Acta,' A. C. L., xx, pars i, 360.

f I. c, t. xvii, f. a — d.

% I. c, p. 544.

§ ' Theoria generationis,' p. 177, t. xxvi, f. 6, 7.

| 'Mem. Acad, des Sc. Inst, de France,' xiii (1835), 380.

^[ 'Icon, plant.,' p. 85.
** 'Theoria generationis,' t. xx, f. a, a.

f-j- ' Neues system der Pflanzenphysiologie,' Bd. iii (1S39), t. xii, f. 39, 40.
%% ' Nova Acta,' A. C. L., xx, pars i, t. xvi.
§§ ' Ann. d. Sc.,' iii seV., t. xvi, 10, 11.

88 HOFMEISTER, ON THE HIGHER CRYPTOGAMIA.

Gottsche is of opinion that the antheridia of the liver-
worts in general have a wall consisting of a double layer of
cells — an inner layer, the cells of which become detached
when ripe and contain colouring matter, and an outer layer
of hyaline, tubular cells, of small height, with transparent
fluid contents. Gottsche's opinion is founded mainly upon
investigations of Haplomitrium Hookeri. He attributes a
similar structure to the antheridia of Fossombronia.* He
is decidedly in error in both cases ; the covering layer
is certainly a single layer of cells, which, when the
organ is fully ripe, give way at the apex, and separate
from one another. This cannot be a matter of doubt
to any one who witnesses the spontaneous opening of
an antheridium under the microscope. But the structure
of the covering layers, even in antheridia, which are still
closed, can be fully made out with a good microscope.
Gottsche's view may have originated in the circumstance
that in Fossombronia, as well as in Anthoceros, the coloured
bodies often lie close to the inner side of the wall of the
cells of the covering layer, so that the somewhat swollen
protuberance of the free outer wall appears to be filled
merely with a clear, watery fluid.

With regard to the outer of the two cellular layers of the
covering of the antheridia of Haplomitrium, a preparation
of which has been figured by Gottsche (1. c, t. xvi, f. 8),
I find that the antheridia of this plant are similar to
those of Sphaginum ; that a thin glassy cuticle encloses
the simple covering layer of the antheridia. In Haplo-
mitrium the boundaries of the cells appear upon this
cuticle in the form of prominent ridges, but this is not
the case in Sphagnum {cymbifolium) . The cells of this
covering layer isolate themselves at the time of the ripen-
ing of the antheridia of Sphagnum, precisely after the
manner of the cells of Haplomitrium ; a median lamella of
the wall of the cells swells up into a gelatinous substance.
By this means the vermiform cells become detached from
one another, and separated from the cuticle.

* /. c, vol. xx, p. 294.

CHAPTER IV.

RICCIA AND RIELLA.

The germ-plant of Biccia glauca is a simple, short,
ribbon-shaped, or three- sided shoot, consisting of homo-
geneous cellular tissue (PL XIII, fig. 1).* The arrange-
ment of the cells of the germ-plant in the direction of the
surface corresponds exactly with that in Pellia epiphylla.
Individual cells of the side edges are transformed into
elongated papillae which are bent forwards ; a few cells
of the under surface grow out into long, radicular hairs.
At an early period there is formed in the middle of the
fore edge a deep, narrow indentation, produced by the fact
that the growth of the lateral portions of the fore edge ex-
ceeds that of the middle (PI. XIII, fig. 1). In this inden-
tation a new shoot originates. It grows rapidly in length,
its fore edge becoming continually wider (PL XIII, fig. 2) ;
the wing-shaped lateral portions of the fore edge of the germ-
plant are thereby stretched far apart from one another. At
the same time the lateral margins of the under part of the
new formation amalgamate with that portion of the two
wings of the fore edge which is directed inwards. Shortly
afterwards new shoots are formed in the angles of both,
at the spot where the amalgamation ceases. An almost
hemispherical mass of cellular tissue originates at the
bottom of the narrow cleft. The arrangement of its few
cells repeats in miniature that of the germ-plant (PL XIII,
fig. 4). On its right and left new shoots are soon produced,
clearly originating from the multiplication of a single
cell. They amalgamate with the median shoot as soon
as their increase in breadth causes their lateral margins to

* I have not been able to procure, under cultivation, the first stages of
development of the spores of Riccia or of Autheceros; in both genera I have
been limited to germ-plants which I have found in their native habitats. It is
strange that two of the most widely spread and common plants should germi-
nate with so much difficulty.

90 HOFMEISTER, ON

touch it. The longitudinal growth of the lateral shoots
soon surpasses that of the middle shoot, and shortly after-
wards the growth of the former in breadth and thickness
also exceeds that of the latter. The result is that the
median shoot, closely surrounded above and below by the
more rapidly growing lateral ones, is pushed to the bottom
of one of the narrow crevices formed by the lateral shoots,
which shoots are more vigorous in their longitudinal growth.
By the multiplication of its cells in the longitudinal
direction the median shoot is blended with the two lateral
ones, which surround it almost entirely, and far exceed it
in size. The shoot formed by the junction of three masses
of cells in a state of active longitudinal growth amal-
gamates at its sides with the advanced portions of the fore
edge of the germ-plant by which it is enclosed. On the
one side it amalgamates with one of the wing-shaped
lateral portions, on the other with the one half of the
median shoot, which in the mean time expanding more and
more in breadth, has assumed an entirely emarginate
shape. By further longitudinal growth the shoots of the
second order make their appearance out of the two narrow
crevices which the fore edge of the germ-plant exhibits, and
which answer to the limits of the median lobe of the fore
edge and its lateral portions. The apex of the young Riccia is
furcate. The apical point of the bifurcation is the middle
of the fore edge of the median shoot. Each point of the
fork exhibits in the middle of its fore edge a deep, narrow
incision, formed by the two lateral component parts of the
shoot of the second order, which almost touch one another.
At the base of this incision is the median shoot, of which
the apex alone is free, and not united in growth with the
lateral ones, and at the sides of which new shoots, being
the median ones of the third order, are in process of
formation. An active multiplication and expansion of the
cells of the median portion of the shoots of the second
order now commences ; this median portion, by its longi-
tudinal growth and the continually increasing width of its
fore edge, pushes asunder the lateral portions of the same
shoot which have hitherto confined it in a narrow crevice.
New shoots originate in like maimer out of its angles.
The subsequent ramification of Riccia follows the same

THE HIGHER CRYPTOGAMIA. 91

rules ; each shoot originates from the blending together of
three sub-shoots, and has only a limited growth. New-
shoots are only formed in the two incisions which the fore
edge of each fully developed wedge-shaped shoot exhibits.
All shoots, with the exception of the first, which proceeds
directly from the spore, undergo complete distortion, caused
by the peculiar growth of their median portion and by the
expansion of the next younger shoots of a new order,
which originate in the incisions of the fore edge of each,
and which amalgamate with the median portion ; their
form passes from a pointed semi-oval, through that of a
wedge, to a furcate shape. The repeated furcate ramifi-
cation of young plants soon renders their entire outline
circular.

The multiplication in a longitudinal direction of the
cells of each of the three parts of which a shoot is com-
posed takes place through the division of the cells of the
fore edge by means of transverse septa inclined to the
horizon (PI. XIII, figs. 7*, 14). The multiplication is much
more active in the median line of the young shoot than at
its sides. The cells of the second degree divide by septa
almost parallel to the upper and under surface of the shoot,
and this division is repeated in the outer of the newly
formed cells, by which means the shoot increases in thick-
ness. Immediately after the appearance of the first of the
above septa each of the two cells which have originated
from the division of each upper cell of the second degree
is usually divided into two by the formation of a transverse
septum, perpendicular to the outer surface, and cutting the
longitudinal axis of the shoot at an angle of 90° (PI. XIII,
fig. V). The cells of the upper half of the flat stem are
consequently, even in their earliest stage, usually one half
shorter than those of the under half. It is only in those
shoots in which the longitudinal growth is especially active
that the transverse division of the cells of the under half of
the stem lags behind that of those cells of the upper
surface which are situated further back from the fore edge
(PI. XIII, figs. 11, 14). Such shoots are usually those
which bear the archegonia. The growth in thickness, the
division by septa parallel to the surfaces of the shoot, is far
more active in those cells which are produced by the

92

HOFMEISTER, ON

multiplication of the cells of the second degree belong-
ing to the upper surface, than in those which are pro-
duced by the multiplication of the like cells of the under
surface. The increase in the number of cells, in the direc-
tion of the thickness, from the apex of the young shoot
backwards, is not unfrequently so rapid that the profile of
the shoot appears like a very slightly pointed triangle
(PI. XIII, fig. 11). The continual increase of the breadth
of the young shoot during its longitudinal growth takes
place by the division of the lateral cells of the fore edge by
means of longitudinal septa parallel to the longitudinal
axis of the shoot (PI. XIII, fig. 4). In a more advanced
stage of growth, the cells lying nearer the middle of the
fore edge also divide by longitudinal septa, slightly diverg-
ing from the direction of the median line. The shoot
then exhibits a middle row of cells, from which the other
cells diverge right and left at different altitudes, like the
rays of a fan. The earliest rudiment of each shoot is
a simple cell, having a trapezoidal basal outline, situated
in the axil of two older shoots (PL XIII, fig. 4, a) ; at
a little later period many such cells lying near one another
are found, in consequence of the commencement of the
longitudinal growth, to be already several times transversely
divided by inclined septa (PI. XIII, fig. 4, b). The
shoot, as it becomes developed, springs forth in the form
of a short projection, having its cells arranged in the order
already described, from the axil formed by the two older
adjoining shoots.

The under side of each joint of the stem of Riccia glauca
exhibits on each side of the median line small, distichous,
obliquely attached leaves, formed of a simple layer of deli-
cate, transparent, cellular tissue (PI. XIII, fig. 3). They
resemble in all their parts those of the Marchantise, and,
like the latter, are for the most part rapidly destroyed by the
bursting forth of hair-like roots. The hollows of the old
roots of Riccia, like those of the Marchantiae, are furnished
upon the inner side with very numerous little points pro-
jecting inwards (PI. XIII, fig 4J).

On stem-joints which have a tendency to form fruit, in-
dividual cells of the upper surface, situated in the angles
of the lateral and of the median shoots, protrude out-

THE HIGHER CllYPTOGAMIA. 93

wards, and this takes place even during the process of the
amalgamation of three shoots into one new shoot (PL XIII,
fig. 7 *). From these cells are developed the organs of
fructification, the antheridia or archegonia. The arrange-
ment of these corresponds to the commissures of the three
shoots which are uniting to form a single shoot, thus
forming two nearly parallel longitudinal rows right and
left of the median line. The hemispherical vesicular pro-
tuberance which projects above the surface of the young
stem-joint divides by a septum inclined to the horizon.
In the upper one of the new cells thus formed division
immediately takes place by a membrane inclined in the
opposite direction (PL XIII, figs. 5, 7 *). In these phe-
nomena of development the archegonia and antheridia,
which originate without any regularity, exactly resemble
each other ; in their earliest condition they cannot be dis-
tinguished from one another.

The cells of the upper side of the young stem which
surround the base of the rudiment of an antheridium ex-
tend themselves upwards, and thus form a membranous
ring which encircles the lower part of the antheridium.
This ring usually consists of six cells (PL XIII, fig. 10);
it is seldom wider. It grows longitudinally by repeated
transverse division of the cells of its free upper edge. The
sheath thus formed soon overtops the apex of the young,
small antheridium (PL XIII, figs. 6, 7 *) ; above the anthe-
ridium it becomes considerably narrower (PL XIII, fig. 9).
The upper part of its inner cavity contains a watery fluid ;
in the lower part, close under the antheridium, air is secreted
at an early period, which by careful pressure may be
driven out at the narrow mouth of the covering of the
antheridium.

The first appearance of the organs of fructification takes
place, as is mentioned above, long before the termination
of the growth of the stem-joint. The increase in thickness
of the surrounding tissue of the surface of the stem nearly
keeps pace with the longitudinal growth of the archegonia
and of the sharply conical covering of the antheridium, so
that the organs of fructification, during their longitudinal
development, are continually enclosed in the tissue of the

94 HOFMEISTER, ON

stem as the latter increases upwards in thickness. In this
way the outer side of the covering of the antheridium
amalgamates with the adjoining cells of the stem. The con-
tents of these united cells of the antheridum-sheaths become
exactly similar to that of the cells of the upper half of the
flat stem ; numerous chlorophyll-granules are formed in
them, and air makes its appearance in the adjoining inter-
cellular spaces. The rudiment of the antheridium, which
as yet consists of few cells, has in the mean time considerably
increased in size, and become transformed into an oval,
cellular body by means of repeated longitudinal and trans-
verse divisions ; this oval body consists of a central group
of cells, with turbid, mucilaginous contents, surrounded by
a layer of tabular cells with watery contents (PI. XII I,
fig. 8). The repeated bisection of the former cells in all
three directions leads ultimately to the formation of a
spherical mass of numerous, very small, tessellated cells,
during the production of which the peripheral layer of
tabular cells is gradually entirely displaced (PL XIII,
fig. 9). The skin-like membrane of the ripening anthe-
ridium becomes closely applied to the inner side of the
covering of the antheridium, but without growing to it.
Each of the small cells produce, during the progress of
growth of the antheridium, a small, lenticular vesicle. When
the antheridium is ripe the walls of those small cells swell
up into a tough jelly, and the outer membrane of the anthe-
ridium assumes a delicate, gelatinous consistence.

The amalgamation of the cells of the tissue of the stem
with the outer side of the antheridium-sheath does not extend
to the young, blunt apex of the latter. Owing to the fact
that the longitudinal expansion of its cells first takes place
after the complete formation of the stem-joints, this free
upper end remains for some time in the form of a rounded,
little cone, concealed between the epidermal cells (PI. XIII,
fig. 9). Suddenly the apex elongates itself considerably ;
by expansion of its cells it often protrudes more than a line
above the surface of the stem. The universal expansion
of its cells causes a widening; of the mouth of the canal
which traverses the axis of the sheath, and which leads to
the antheridium (PI. XIII, fig. 10). Through this canal

THE HIGHER CRYPTOGAMIA. 95

(according to Bischoff) the contents of the antheridinm
escape in the form of mucilaginous drops.

In the apical cell of the rudiment of an archegonium
division takes place in often-repeated succession by alter-
nately inclined septa. Here, also, the cells of the second
degree divide immediately after their formation by radial
septa. Immediately after the formation of the radial
septum which divides the cell of the second degree, septa
parallel to the axis appear in one of the four longitudinal
rows of cells of the third degree ; these latter septa divide
the mother-cells into inner three-sided and outer four-
sided cells, so that the organ now consists of a central
string of cells, which is surrounded by a single layer of
cells arranged in sets of four cells of equal height (PL
XIII, figs. 12, 13). The apex of the young archegonium
swells to a clavate shape ; contemporaneously, the basal
cell of the central row of cells begins to enlarge its circum-
ference, whereby the base of the archegonium becomes
distended (PL XIII, fig. 13). The cellular tissue sur-
rounding the archegonia, so far from amalgamating with
their outer cellular layer, is often, on the contrary, ex-
panded into a wide cavity surrounding the base of the
archegonium (PL XIII, fig. 15). The cells of the stem,
on the other hand, usually become very closely approximated
to the neck of the archegonium, without, however, be-
coming actually united to it. In comparison with other
mosses, the basal cell of the central string of cells becomes
considerably enlarged; this takes place, however, at a
somewhat later period, shortly before the rupture of the
apex of the archegonium. Within the fluid contents of
this basal cell there is produced a free spherical cell
(PL XIII, figs. 14, 15). This grows by degrees, until it
fills the mother-cell. There are but few of the Muscales
in which this cell is so clearly distinguishable as in Riccia.
The remaining cells of the central string are dissolved,
and the apex of the archegonium opens. The archegonia,
thereupon, either wither, which is a rare occurrence, or a
fruit is formed in their ventral portion. The first indica-
tion of fruit-formation is the division, by means of an in-
clined septum, of the free cell which has originated in the

93 HOFMEISTER, ON

large basal cell of the central string. The upper of the
two newly formed cells is then divided by a septum in-
clined in the opposite direction (PL XIII, fig. 16*). In
the apical cell of the now 3 -cellular young fruit the
division is repeated several times by alternately inclined
septa. The cells of the second degree divide by radial
longitudinal septa, and the cells thus produced divide into
three-sided inner and four-sided outer cells, after the manner
of the one row of cells of the third degree belonging to
the archegonium. In the four- sided cells, the division is
repeated by radial septa, and then by longitudinal septa
parallel to the axis of the fruit (PL XIII, figs. 17, 18).
When the young fruit, which from first to last is almost
globular, has attained its full size, the somewhat tabular
cells of its upper surface divide by a longitudinal and
transverse septum perpendicular to the outer surface, so that
the outermost cellular layer of the fruit consists of cells of
which the basal outline is four times smaller than that of
the inner cells (PL XIII, fig. 19).

In each of the latter there ensues a well-defined, gelati-
nous thickening of the cell-wall (PL XIII, fig. 19). Soon
afterwards the cells become disconnected by the dissolution
of the oldest outermost portion of the cell-wall. The
spherical cells thus set free are the mother-cells of the
spores. In each of them four special-mother-cells origi-
nate, each of which produces a spore. After the indivi-
dualization of the spores the wall of the half-ripe capsule
is absorbed, so that the ripe spores lie free in the cavity of
the globular calyptra. This latter is formed by the re-
peated division into two parts of the cells of the ventral
portion of the archegonium, by means of septa perpendi-
cular to the outer surface, such division alternating once
with a division by septa parallel to the outer surface.
The calyptra of the half-ripe fruit consists of two layers of
cells (PL XIII, figs. 17, 19) ; towards the period of maturity
the inner one of these disappears. The neck of the arche-
gonium lasts till the fruit is ripe. The cells often assume
a beautiful wine-red colour. In rare instances those cells
of the impregnated archegonium which lie beneath the
central cell of the ventral portion multiply, so that the

THE HIGHER CRYPTOGAMIA. 97

form of the organ becomes similar to that of the arche-
gonium of a moss.

Biccia glauca not nnfreqnently produces gemmae in the
middle of the tissue of the older shoots — small, fleshy masses
of cellular tissue, filled with granular mucilage. Their out-
line resembles that of germ-plants ; there is, however, the
material distinction that the two lateral portions of the fore
edge are not formed at an earlier period than the middle
one, or, to speak more accurately, the middle shoot
does not, during the formation of the lateral ones, continue
in its lowest stage of development, but it forms a prominent,
flattened, conical point at the time when the lateral por-
tions begin to protrude themselves. The arrangement
of the cells agrees with that of the shoots of perfect
plants. Gemmae which remain long surrounded by the
tissue of the stem exhibit the internal disintegration of
the tissue which I have figured in Anthoceros and
Blasia. The commonest of all liverworts is, strange to
say, one of the least known. The numerous investigations
and figures of Riccia relate almost exclusively to the organs
of fructification (Schmidel, in ' Icones,' t. xliv, xlv ; Hed-
wig, ' Theoria generationis,' ed. ii, 7, 31; BischofF, ' N.
A. A. C. L.,' t. xvii, p. ii, fig. 911//; Lindenberg's large
monograph in vol. xviii of the last-mentioned Proceedings ;
and lastly, Unger, ' Linnaea,' 1839). The erroneous notion,
that a very low state of development of the fruit must be
accompanied by an equally low state of development of the
vegetative organs, seems to have prevented the accurate
investigation of the phenomena of growth in Riccia, which,
in comparison with Anthoceros and Pellia, are very com-
plicated. Lindenberg expressly and repeatedly denies to
the genus that higher organization, and even the leaves,
which he figures most distinctly in very many species. The
widely spread notion that the growth of Riccia is radiate,
proceeding in all directions from a common median point,
may be disproved by the examination of any clod of earth
taken from any stubble field in autumn where Riccia
glauca has begun to germinate.

Hiclla Reuteri, Mont. — Amongst the various forms of
liverworts, Montague's genus Riella (' Ann. Sc. Nat./ 3rd

7

98 HOFMEISTER, ON

ser., t. xviii, p. Ill ; Duriena, 1. c, t. i, p. 228 ; t. ii, p. 50)
is the most remarkable, on account of its very peculiar
habit. The Algerian Riella {Duriena) lielicophylla is the
most striking of all ; its upright leaf, which is three inches
high, and shaped like a winding staircase, being one of
the most wonderful of vegetable forms. My investiga-
tions of this remarkable genus were made on a species
found by Reuter at Geneva, which represents in miniature
the vegetative phenomena of the North African species. I
am indebted for the materials for my work to the kindness
of the discoverer, who sent me numerous living specimens.

Young individuals, whether produced from spores or
adventitious shoots (PL XIV, figs. 1 — 4), are formed of
short rows of cells, which pass at the fore end into a small,
cellular surface. The arrangement of the cells is that
which is common to the Iliccieae and the Marchantiese,
viz., in pairs and flabelliform, originating from two cells of
the first degree, which are divided alternately by transverse
and longitudinal septa. In the young state of the plant
there is an excess of formation of transverse septa, nearly
at right angles to its median line, and consequently of
longitudinal growth. At an early period the multiplica-
tion and expansion of the cells of one side of the fore edge
considerably exceed that of the other side, so that the
punctum vegetationis of the young Riella is turned on one
side (PL XIV, fig. 2).

Contemporaneously with the appearance of the first
leaves, the plant develops a mid-rib, by the production in
certain cells of septa parallel to its surfaces ; this mid-rib
is a strip of massive cellular tissue, consisting sometimes
of as many as six layers of cells, which runs along the less
highly developed side of the shoot. The rib forms one
margin of the flat stem, which may be compared to a stem-
joint of Marchantia, of which the membranous left-hand
wing has been removed. The helicoid winding of the
stem is produced by the lateral twist which takes place in
the axis as it grows obliquely upwards, and which is caused
by the more rapid development of the left-hand side wing.
The twist is always to the right.

Leaves are formed only on the mid-rib. The fraction 2^

THE HIGHER CRTPTOGAMIA. 99

represents their arrangement. Each of the surfaces of the
plant has two longitudinal rows. The leaf originates from
the multiplication of a single cell protruding above the
surface of the terminal bud (PI. XIV, fig. 9). In its early-
stages, and in those leaves which are nearest to the fore
edge of the rib, the successive cell -formation corresponds
exactly with that of the scales of ferns. The leaves which
lie nearer to the membranous wing are considerably and
un symmetrically developed in breadth in their middle
region (PL XIV, fig. 8).

The succession of the shoots in Riella, as in the other
Riccieae and Marchantieae, is pseudo-dichotomous. The
first visible ramification takes place usually in the early-
youth of new individuals, before the appearance of the
first leaves. The relation of the two side shoots to the
middle principal shoot, of which the development is ar-
rested, and the amalgamation of the latter with the former,
may be very easily observed in the simple cellular surface
(PI. XIV, figs. 4, V).

The growth of the antheridia commences by the swelling
of a marginal cell of the membranous wing close to the
punctum vegetationis, and by the separation of the vesicular
protrusion from the original cell-cavity by means of a
transverse septum. By the exuberant growth of the cells
adjoining its base the rudiment of the antheridium is at
once surrounded by a closely-fitting sheath (PI. XIV, figs.
10, 11). After one or several divisions have taken place
in the cell of the first degree by means of transverse septa,
and the consequent formation of a short stalk, there occurs
in the hemispherical cell a series of divisions coinciding
with the like process in Riccia, by which there is produced
an oval body consisting of cubical cells, the mother-cells of
the spermatozoa, surrounded by a layer of large, flat cells
(PI. XIV, fig. 12). The growing antheridia now appear
deeply imbedded in the folds of the membranous wing
(PI. XIV, fig. 13). Antheridia and archegonia are always
situated on different shoots. New individuals first produce
antheridia. Archegonia usually appear on their shoots of
the third, fourth, or fifth degree. The archegonia are
situated in the axils of leaves, and are distinguished by a

100 HOFMEISTER, ON

large, central cell, with comparatively small germinal vesicles
(PL XIV, figs. 14"' *).

The base of the young archegonium is surrounded by
a small, annular sheath, which, before impregnation, is
only from one to four cells in height (PL XIV, fig. 14 b).
After the commencement of the formation of the fruit
this sheath grows rapidly into a narrow-mouthed, pitcher-
shaped covering, consisting of a single layer of cells
(PL XIV, figs. 12, 13, 18).

The impregnated germinal vesicle swells at once to the
size of the pear-shaped ventral cavity of the archegonium
(PL XIV, fig. 13), and follows the enlargement of that
cavity, which enlargement is caused by the active multi-
plication of the cells enclosing it. The first division of
the primary cell of the fruit takes place by a horizontal
septum, which divides the cell into a semi-oval superior,
and a filiform inferior, moiety (PL XIV, fig. 15). By
repeated transverse division the latter becomes the fruit-
stalk, consisting of a single row of cells, the lower end
of which, at a later period, and by means of divisions
caused by septa parallel to the axis, becomes transformed
into a clavate, cellular body (PL XIV, fig. IS). The
upper half becomes the capsule of the fruit ; according to
the general rule in the Ricciese and Marchantieae, it mul-
tiplies by repeated divisions of the cells of the first de-
gree by means of septa inclined alternately to the rio-ht
and to the left (PL XIV, fig. 15). After about eight
such divisions the capsule becomes globular; its outer
layer, the cells of which become tabular, forms the wall.
The cells of the interior, becoming loosened and spheri-
cal in shape, perfect themselves in different ways. The
contents of half of them become turbid from numerous
fine granules, and their walls increase in thickness.
These are mother-cells, containing in their interior four
special-mother-cells, usually arranged in a tetrahedron,
from which the spores, which are clothed with a strong,
delicately marked episporium, are developed (PL XIV,
fig. 19). The formation of only two spores in a mother-
cell is an irregularity of frequent occurrence. The other
cells of the contents of the capsule remain thin-walled,

THE HIGHER CRYPTOGAMIA. 101

and starch-granules appear in their interior (PI. XIV,
fig. 19/5). They change no further until maturity. This
double nature of the cells of the interior of the capsule
brings to mind the development of the elaters of the
Targionieae and Marchantieae. The young conditions of
the elaters of the latter answer exactly to the permanent
state of those cells of Riella which are intermixed with
the spores and contain starch-granules. Riella thus, in
more than one point, forms an intermediate link between
the Riccieae on the one hand, and the Targionieae and
Marchantieae on the other.

CHAPTER V.

MARCHANTIEiE AND TARGIONIE^E.

Marchantia polymorphs Fegatella conica, Bebouillia hemi-
spheric^ Lunularia vulgaris. Targionia hypophylla.

The growth of the Marchantieaa and Targionieae resem-
bles in its principal phenomena that of Pellia, Riccia,
and Anthoceros. The essential circumstance, viz., the
origin of each new shoot by the amalgamation of three
shoots, which are developed in one of the two in-
dentations of the fore edge of an older shoot, is in these
plants, especially in the genera Lunularia and Fegatella,
more clearly marked than in any others*

The vegetative organs of Marchantia polymorpha, Fega-
tella conica, Bebouillia hemispherica, Lunularia vulgaris, and
Targionia hypophylla exhibit great similarity in development

* The rudiments of those shoots of Fegatalla conica which are to be deve-
loped in the early spring originate in the preceding October; on the right and
left of a nearly hemispherical mass of cellular tissue, situated at the bottom
of one of the two indentations of the fore edge of the fully developed shoot of
the next higher order, there are formed two smaller, almost conical shoots,
which, by amalgamating with the one between them, form the bud of the new
shoot. The shoot grows slowly in a longitudinal direction until the commence-
ment of winter ; the fore edge of the median shoot becomes, at the same time,
contiuually wider (PI. XVI, fig. 1, middle of November). After the coldest
months are over there is formed on either side of the median lobe the rudi-
ment of a new shoot, which has already attained a tolerably perfect condition
at the time when the longitudinal expansion of the oldest hinder cells of the
shoot formed at, the commencement of winter begins to cause the latter to
protrude out of the indentation of the edge of the stem-joint of the previous
year. The shoot whose longitudinal expansion commences, appears at this
time as if bent upwards ; a thick-fleshed, small mass of cellular tissue, already
slightly furcate at the fore edge by the commencement of the longitudinal
development of the shoots of a new order. The lateral margins of the shoot
are bent strongly inwards, and it is closely folded together in its median line.

HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 103

and structure. The longitudinal growth of each shoot
is caused by repeated division in its apical cells, by means
of alternately inclined septa (Lunularia, PL XV, fig. 19;
Eegatella, PL XVI, fig. 3). Soon after the first division of
this kind has taken place in the mother-cell of a new
shoot (which mother-cell lies at the bottom of the axil
of two older shoots), the number of the apical cells is
doubled by the appearance of a longitudinal septum
(PL XVI, fig. 2). The fore edge of the shoot widens
continually during and until the cessation of its longitu-
dinal development, by means of repeated division of the
apical cells by longitudinal septa ; this increase in breadth
is more or less rapid, according to the circumstances under
which the plant is growing, and according to the species
of plant. The differences in habit in different species, as
well as in individuals of the same species growing under
different circumstances, depend, in the first place, upon
whether the lateral margins of the new shoots amalgamate
with the adjoining lobes of the fore edge for a considerable
length, or not. Those shoots of Pegatella and of
Rebouillia wThich are formed late in autumn, which remain
quiescent during the coldest part of the year, and develope
themselves in early spring, remain completely separated
from the projecting portions of the shoots of the previous
year ; this is the cause of the jointed appearance of the
leaf-like stem of these species. In Marchantia, in Targionia
under all circumstances, and in the summer shoots of
Pegatella and Rebouillia, the amalgamation is, on the other
hand, very complete. In the next place, differences of
habit depend also upon the length of the lines of amalga-
mation of the three shoots which combine to form one
shoot. In Pegatella, and in specimens of Marchantia poly-
morpha and Lunularia vulgaris, which grow in very moist
places, the amalgamation is far more considerable than in
specimens of the same species from dry habitats,* or than

* The length of the amalgamation is manifestly to be measured by the
number of cells, and not by lines and inches. The expansion of individual
cells has the greatest influence upon the absolute length of the shoots. The
latter becomes quite enormous when new shoots of Marchantia polymorpha,
covered by older portions of the mother-plants, are making their way to the
light.

104 HOFMEISTER, ON

is the case in Rebouillia and Targionia. Differences of
habit depend also upon the greater or less rapidity of the
expansion of the fore edge of the shoots during their
longitudinal growth, and, lastly, upon the fact whether the
older shoots die and moulder away with greater or less
rapidity. In Ttebouillia hemispheriea and Fegaiella cornea
they last for several years ; in Targionia and Marchantia
the decay of the older generation of shoots begins very
shortly after the complete formation of the next youngest
shoots. It often happens that almost every trace of the
(pseudo) furcate ramification of the plant is obliterated by
the fact of a new shoot being developed in one only of the
indentations of the fore edge of an older shoot, the other
new shoot, situated in the other indentation, becoming
abortive. This is often the case in Rebouillia and Tar-
gionia. The buds (bulbils according to Mirbel) of Lunu-
laria and Marchantia, which are formed in special
receptacles on the median line of the shoots, afford a
particularly striking example of the above species of rami-
fication. These receptacles are formed in the following
manner: — in the earliest stageof the shoot, cell- multiplication
commences, either all round the spot where the buds are
destined to be formed, or in a semicircular chain of cells
(the semicircle lying open to the front) of the upper side of
the shoot. This cell-multiplication gives rise in Mar-
chantia to an annular, in Lunularia to a horse-shoe shaped
cushion. The division by septa parallel to the surface, of
those cells of the upper side of the shoot which are enclosed
by the cushion, soon ceases, whilst it continues for some
time in the cells lying outside. Thus the space of the
upper surface which is enclosed by the cellular rampart,
and is destined to form gemmae, becomes a depression.
The margin of the wall grows in Lnnularia into a delicate
membrane (PI. XV, fig. 19), consisting of a single layer of
cells. In Marchantia from sixteen to twenty teeth sprout
from it (PI. XV, figs. 1, V), which incline towards one
another when young, and thus cover the gemmae ; after-
wards they become upright. The history of the develop-
ment of these teeth is as follows : — every other cell of the
edge of the annular wall expands considerably outwards.

THE HIGHER CTU'PTOGAMIA, 105

The protruding portion is separated by a transverse septum
from the rest of the cavity of the cell, which is then divided
by a longitudinal septum. The cells which are elevated
above the margin of the wall are transformed into flat
teeth, consisting of a single row of cells, resulting from a
division by transverse septa, which is continually repeated
in each apical cell (PI. XV, fig. 1*). Repeated division
takes place in the interstitial cells by means of longitudinal
septa perpendicular to the broader surface ; and by this
division, which begins at the base and progresses to the
apex with increasing intensity, the teeth, at a later period,
increase in breadth. At the same time the circumference
of the annular wall of the bud- receptacle increases, through
the division of its cells by means of longitudinal septa.
At the points of origin of the teeth this latter increase cor-
responds with the expansion of the teeth ; underneath it is
much less. By this means the form of the edge of the
bud-receptacle becomes that of a cup.

Some time before the appearance of the marginal teeth
the formation of the first gemmae commences. Individual
cells of the base of the receptacle produce a papilla upon
the middle point of their free upper wall (PI. XV, fig. ls>.
This papilla is soon separated by a transverse septum
from the rest of the cell-cavity. The new semi-oval cell,
after previous longitudinal expansion, is divided by a
transverse septum (PI. XV, fig. V). The lower one of
the cells thus produced is the stalk, the other the mother-
cell of the gemma. The latter increases considerably in
breadth, and by means of transverse division, which is always
repeated twice in the terminal cell, it becomes transformed
into a row of four short, wide, and low cells. Each of them
divides by a longitudinal septum (PI. XV, fig. 2). The
three lower pairs of cells thus formed are divided by septa
parallel to the last-mentioned septum ; the lower pair once,
the two higher pairs twice. The repetitions of the division
occur, as is usual in similar cases, always in the outer cells.
Each of the two apical cells of the bud, on the other hand,
divide by septa having a strong lateral inclination, into an
inner and an outer cell, the former having a trapezoidal,
and the latter a triangular basal, outline. The former is

106 HOFMEISTElt, ON

soon divided by a septum at right angles to the longitu-
dinal line of the bud. The latter cell, after previous trans-
verse expansion, divides by a septum parallel to the chord
of the arc represented by that portion of the margin of
the bud to which the cell in question belongs. The outer
ones of the newly formed cells then divide by septa at
right angles with the last-formed septum (PI. XV, figs.
3 — 5 ; and compare Nageli's excellent account of this pro-
cess, 'Zeitschr. f. Bot.,' Hft. 2, S. 150). The further in-
crease in the cells of the bud is caused by the growth of
septa in the cells of its fore edge alternately at right angles
or parallel to its margin, and by the formation of septa
parallel to the margin in the cells of the edge of its lower
part. The increase in breadth of the apex exceeds, at an
early period, that of the base (PI. XV, figs. 3, 4).

The longitudinal growth of the bud is limited, as is the
case with all the shoots of the Marchantiese. When it
is finished a very considerable increase in the breadth of
the lower part of the bud commences. Here the marginal
cells divide repeatedly by septa parallel to the margin,
alternating with radial septa. The marginal cells also of
the upper part, with the exception of those of the apex,
multiply in like manner, although less actively ; they are
soon overtaken by those of the lower part. The cells,
however, of those two places on the lateral margins at which,
at an earlier period, the upper, wider half of the bud
separated itself from the lowTer, narrower portion, take no
part whatever in this multiplication (PL XV, fig. 7), and
as little also in the important expansion in length and
breadth which occurs shortly afterwards in the remaining
cells of the buds. In this way two very deep, lateral in-
dentations are produced in the middle of the buds, the inner-
most space of which indentations is occupied by a group
of small cells, with a trapezoidal basal outline (PI. XV,
figs. 7, 8). At the time when as many as ten cells can be
counted in the longitudinal line of the bud, this group
appears as a single layer of cells. Then, for the first time,
it begins to grow in thickness ; in the first place, by the
division of the cells of the middle region by horizontal
septa (PI. XV, fig. 1*). For a still longer period the Ion-

THE HIGHER CRYPTOGAM I A. 107

gitudinal growth of the bud is produced exclusively by di-
vision of the apical eells, by means of septa at right angles
to the surfaces of the bud; the transverse septa which
appear in the apical cells are strictly vertical ; the fore
edge of the bud is a simple cellular layer. Afterwards, for
the first time, when the middle region has become more
and more thickened by the repeated formation of septa
parallel to the surface, and when this thickening has ad-
vanced close to the fore edge, the transverse septa appear in
the apical cells, inclined alternately upwards and downwards,
and parallel to the circumference of the bud. Thus the
form of longitudinal growth of the bud passes into that
which occurs in the shoots of older plants.

The arrangement of the buds of Lunularia and of
Marchantia, with respect to the longitudinal axis of the
shoot upon which they originate, is a very constant one ;
their surfaces are always at right angles to that axis
(PL XV, figs. V, 19). Until their longitudinal growth is
almost completed, the buds are surrounded by a trans-
parent gelatinous mucilage. When the growth of the bud
in length and breadth is ended, the cell which supports it
dies and withers, and the bud becomes free. A. moist sub-
stratum outside the receptacle is all that is now necessary
for its further development.

Under such circumstances some of the cells of its under
side first grow out into rootlets. Then new shoots begin
to be developed from the bottom of the lateral indentations
of the bud. The middle cell of the group which has been
so long arrested in its growth, and which is somewhat
larger than its neighbours, becomes the mother-cell of the
first new shoot (PI. XV, fig. 8). It divides by a transverse
septum, and the front one of the new cells by a longitudinal
septum. The division of the latter by laterally inclined
septa causes the further growth of the shoot, which pro-
ceeds precisely in the same manner as that in which
the new shoots of Pellia epiphyUa develope themselves,
with this difference only, that the transverse divisions of
the apical cells are always produced by means of septa
inclined to the horizon in alternate directions. The lateral
margins of the young shoots thus formed amalgamate

108 HOFMEISTER, ON

for a considerable extent with those of the indentation of
the bud. The cells which have amalgamated expand con-
siderably in length, and to some extent in breadth. When
a shoot is formed in each of the two lateral indenta-
tions the bud becomes developed into a wide band, on one
side of which may be seen the spot at which the bud was
attached to the cell which bore it, and which spot is con-
spicuous from its brown colour, and by the arrangement
of the cells by which it is surrounded. This is the case
in Marchantia pohjmorplia (PL XV, fig. 9). In Lunularia
vulgaris, on the other hand, it is a rule almost without ex-
ception that a shoot is developed only on one side of
the bud, the shoot on the other side becoming abortive.
Here the bud in its further growth, assumes the form of
a disc drawn out in breadth, and having an indentation
on one side. On the other side it sends out a long
band, constricted at the fore edge, and on a third side
the primary place of attachment is still visible (PL XV,
fig. 20).

On both sides of the new shoot, and in the angles
which it forms with the prominent portions of the lateral
margin of the bud, two new cellular masses are formed
which are capable of development — in the first place a
median, and then two lateral shoots. The shoot com-
posed of the three amalgamated shoots unites by its lateral
margins with those portions of the next oldest shoot
which adjoin it on the right hand and on the left, and it
soon makes its appearance out of the indentation, in the
form of a flat mass of cellular tissue, having two notches
at the fore edge, and becoming wider in front.

A second form of growth, in which the shoots make
their appearance in irregular positions, occurs occasionally
in Lunularia and Marchantia, and more frequently in
Targionia, Rebouillia, and Fegatella. A process of cell-
multiplication commences in individual cells (usually near
the median line) of the under side of perfect shoots, by
means of which slender, delicate shoots are produced, which
soon throw out rootlets, and which, by the decay of their
posterior parts, separate from the mother-plant and be-
come independent individuals. They exhibit exactly the

THE HIGHER CRYPTOGAMIA. 109

same arrangement of the cells as the vigorous normal
shoots of the mother-plant ; this may be observed most
clearly in Fegatella conica. The mode of ramification of
this second form of bud agrees with that of germ-plants ;
the fore edge widens considerably, the lateral portions
grow more vigorously than the median point, and from the
latter a new shoot protrudes, at whose sides the shoots of
a new order originate. This process differs materially
from the development of the bulbils. There is here the
same difference as exists between the development of the
germ-plants and the buds of Riccia.

The leaves of the Marehantiese are delicate lamellae of cellu-
lar tissue, closely pressed to the under side of the flat stem.
In an advanced state they sometimes exhibit at the base a
double layer of cells containing a small quantity of chloro-
phyll, the remainder consisting of a single layer of hyaline
cells. They develope themselves in a backward direction,
towards the place where three shoots unite to form one shoot,
and are situated on the under side of the shoot, in two rows
parallel to its longitudinal axis, arranged according to the
fraction J. The first rudiments of the leaf are formed as
follows : — one of the cells of the under side of the stem
protrudes outwardly, and the protuberance becomes divided
from the original cell-cavity by a transverse septum (PL
XVI, fig. 15). At this time the stem is but little developed
in breadth, and is almost semicircular in a transverse
section. The rudiment of the leaf increases in length by
repeated transverse division of its apical cell. The cells
of the second degree are divided by longitudinal septa
(PI. XVI, figs. 15, 16). In Fegatella conica this division,
even in the youngest stage of the leaf, extends as far as the
apical cell ; the leaf, when only four cells in height, appears
to consist of a short, double row of flat cells (PI. XVI,
fig. 11). The three pairs of interstitial cells divide by
septa parallel to the margin, and the two apical cells by
septa inclined somewhat laterally. The two inner ones of
the four cells which at this period constitute the fore
edge of the young leaf are now divided by transverse
septa, and the four cells thus formed by longitudinal septa
(PI. XVI, fig. 12). The outline of the leaf then becomes

110 HOFMEISTER, ON

rounded by a process of cell-formation which appears
very similar to that by which the cells of the very young
gemmae of Marchantia increase in breadth (PL XVI, fig.
13). The cell-multiplication on the side of the leaf furthest
from the median line of the shoot soon exceeds that of the
other side, causing the one-sided appearance which is
usual in the leaves of Marchantia. The cell-multiplication
is arrested at the apex, whilst it continues at the base.
Many of the marginal cells grow into crooked, short, bi-
cellular, clavate hairs, similar to those which are found close
under the fore edge of rapidly growing shoots of Pellia, as
well as in the young parts of many other Jungermanniae.
Individual cells, arranged at definite distances on the
margin, multiply for a longer period than their neighbours,
by which means the leaf soon becomes angular.

The development of the leaves of Targionia, Rebouillia,
Lunularia, and Marchantia, appears not to differ essentially
from the above. In Marchantia polj/morpha even the
leaves exhibit the tendency, common in these plants, of
sending out from the margins of their vegetative organs
dentate, chaffy processes, a tendency which is seen on
the marginal scales on the edges of the bud-receptacles
on the perichaete and perigone. By these processes the
leaves are beautifully fringed.

The well known characteristic structure of the flat stem
of the Marchantieae is marked by the separation of the
tissue of the stem into — first, an inferior layer of large,
very elongated cells, without intercellular spaces; — secondly,
a layer superimposed upon the latter layer, and con-
sisting of moniliform rows of cells, separated by wide
air-cavities and rich in chlorophyll, which layer is di-
vided into partitions by rhomboidal, cellular walls, each
consisting of a single stratum ; — and, lastly, an epider-
mis with transparent cell-contents, covering the latter
layer, which is in close connexion only with the cellu-
lar walls just mentioned, and is pierced by a stomate
of peculiar structure at the middle point of each of the
partitions of the underlying layer. The foundation of
this peculiar structure is laid at a very early period.
At a little distance behind the punctum vegetationis of

THE HIGHER CRYPTOGAMIA. Ill

the very young shoot, long before the completion of its
growth in thickness, air-cavities are formed just under
the upper surface, separated from it only by a single
layer of cells (PI. XV, fig. 21; PL XVI, fig. 3). The
portions of tissue between the air-cavities form a network
of single rows of cells. As these cells continue to divide
by septa parallel to the surface of the stem, the lid
of the air-cavities is carried upwards. The base of
the cavities is quite flat. Lastly, after repeated pre-
vious bipartition of the cells of the base, by means of
vertical septa placed crosswise, the latter cells protrude
upwards (PI. XV, fig. 21), and by repeated transverse
division are quickly transformed into the monihform
chains of cells which, when the shoot is perfected, are
pressed closely to one another and fill up the air-cavi-
ties.

The epidermal cell which is situated over the middle
of each air-cavity separates by repeated bipartition into
four (Marchantia), six (Fegatella, PI. XVI, fig. 4), or
more (Rebouillia) three-sided cells arranged in a circle.
In the centre of the circle the cells part from one
another; a polyhedral opening is formed, the circumfer-
ence of which, owing to the expansion in a tangential
direction of the surrounding cells, is often considerable,
and through which the air-cavities, in which air is secreted
at an early period, comes into contact with the atmo-
sphere. The first development of the stomata of the Mar-
chantieae is only distinguished from that of higher plants
by the fact that more than one bipartition of the mother-
cell precedes the opening of the commissure of the cells
which form the boundary of the opening.

The cells, from four to eight in number, which sur-
round the stomata of the Marchantieae divide, during the
expansion of the stem to which they belong, by means
of septa parallel to the small side walls ; this often occurs
repeatedly, so that a hollow arch, with a perforated apex,
is formed over the middle point of the air-cavity. The
outer walls of the circular, wart-like protuberance of the
epidermis divide also by radial septa.

The inflorescence of a Marchantia owes its origin to the

112 H0FME1STER, ON

preponderating development in thickness and length, and
the proportionally small development in breadth, of the
median component of the last vegetative shoot. In its
earliest youth it exhibits a hemispherical, and at a some-
what later period a cylindrical, mass of fleshy, cellular
tissue, with a bluntly rounded apex (PI. XVI, fig. 5 ;
PI. XI, fig. 10). Its longitudinal growth results, as is
the case in vegetative shoots, from repeated division of the
apical cell by means of alternately inclined septa, except
that at the first commencement of the formation of the in-
florescence no more than one apical cell is present (PI. XVI,
fig. 5). During the further development there is formed
on its under side a deep channel, which is (PI. XVI,
fig. 7) destined to receive the rootlets which are produced
at a later period by the upper pileate portion, into which
the apex of the young rudiment of the head of the fruit is
transformed by means of active growth in the direction of
its breadth. The under side of the stem of some species
{Marchantia polymorpha, PL XVI, fig. 17, for instance)
exhibits two such channels. In both cases the channels
appear to originate in an active multiplication of the cells of
the inverted sides of the stem of the receptacle. The root-
lets first appear from the lower end of the channel, and pene-
trate into the ground.

The shoot which produces the inflorescence bears nu-
merous narrow, scattered leaves, in which the apex always
consists of one cell and the base of (at the most) a few
cells. The leaves are not produced on the apical portion,
which eventually forms the fruit. It may often be observed
that the cells of the base in these leaves multiply for a much
longer period than those of the apex.
i The lateral portions of the undermost oldest parts of the
common stem of Bebotnllia hemispherica extend consider-
ably forwards ; they close together so as to form a very
narrow, linear fissure in front of the transversely oval chan-
nel, and they amalgamate with the prominent lateral por-
tions of the fore edge of the shoot upon which the fruit-
stem is situated. The outer surface bears connivent leaves
above the apex of the rudiment of the inflorescence. The
longitudinal channel of the under side of the fruit- stem does

THE HIGHER CRYPTOGAMIA. 113

not reach quite to its base ; it projects in the form of a
blunt knob into the indentation of the fore edge of the last
vegetative shoot (PI. XII, fig. 17).

The differentiation of the tissue of the leafy, expanded,
vegetative shoots is not continued into the stem of the fruc-
tifying shoot. At the point where it is attached to the next
older shoot the upper side of the stem decreases by a steep
inclination to the extent of the height of the layer which
bears the air-cavities (PL XV, fig. 12 ; PI. XVI, fig. 17).

The archegonia spring from the lateral margins of the
receptacle in the form of cylinders of cellular tissue directed
obliquely upwards (PL XV, fig. C). The essential features of
their development and structure correspond with those of
the J linger manniee and the mosses. Very soon after the
appearance of the archegonia the portion of the receptacle
above them begins to grow considerably in breadth, and
also downwards. The archegonia, in consequence, appear
shortly afterwards to be situated on the under side of the
expanded receptacle (PL XV, fig. 11; PL XVI, fig. 7). The
receptacle of Rebouilla hemispherica usually produces onlv
four archegonia ; sometimes one more, frequently less. The
cells of the upper surface of the ventral portion of the
archegonium divide at an early period by septa parallel to
the axis ; even before the bursting of the apex the central
cell is surrounded by a double layer of cells (PL XVI,
fig. 17). The neck is considerably bent upwards. The ex-
pansion of the receptacle above the archegonia takes place
at a late period compared with the other Marchantieae,
i. e. not till after the opening of the apices of the arche-
gonia. The growth of the margin of the receptacle down-
wards is at first more vigorous between the archegonia than
above them.

In the neighbourhood of impregnated archegonia these
circumstances are altered. The tissue of the receptacle
above them increases in mass not less actively than in their
neighbourhood. Afleshysheath is formed, encircling the fore
part and sides of the swollen ventral portion of the arche-
gonium. Behind the young calyptra also the margins of the
sheath approximate to one another, so as to form a narrow
fissure ; the bent neck onlv of the archegonium projects out

8

114 IIOFMEISTER, ON

of the narrow covering which is closely attached to the
calyptra (PL XVI, fig. 20). Viewed from the outside, these
processes of the receptacle appear like fleshy appendages of
its margin. The number of them is the same as that of
the impregnated archegonia, viz., from one to five. (See
Bischoffs figures, ' N. A. A. C. L.,' vol. xvii, part 2, pi. 49,
figs. 1 — 4.)

The tendency of the ventral portion of the archegonium
of Rebouillia to develope itself largely is especially remark-
able in archegonia just impregnated. Here the multipli-
cation of the cells near the central cell is so rapid that the
latter becomes a wide, flask-shaped cavity, even before the
occurrence of the first division of the germinal vesicle con-
tained in its interior. This elongated, ellipsoidal cell lies
free in the cavity, entirely imbedded in transparent muci-
lage (PI. XVII, fig. IS).

The fruit-rudiment in Reboivillia, like that of Riccia,
Targionia, Marchantia, and Fegatella, exhibits the remark-
able species of growth which occurs in the fruit of mosses,
although, in other respects, the plants just mentioned
are nearer to the Jungermannise than to the mosses.
This growth consists in the division of the mother-cell by
a strongly inclined septum, and a continually repeated di-
vision of the apical cell of the fruit-rudiment by means of
septa inclined alternately in two directions. The form of the
young fruit-rudiment is very slender (PI. XVI, fig. 19); it
is only a double row of elongated cells. The longitudinal
growth, however, soon ends ; a considerable multiplica-
tion of the cells commences in a diametrical direction,
a multiplication which is more active at the apex (the future
capsule) and at the base (the growing knobby enlargement)
than in the middle (the future fruit-stalk). The increase
in the size of the fruit is so considerable at the approach of
maturity that it usually entirely destroys the upper part
of the calyptra ; it then lies naked in the fleshy sheath
formed by the growth of the margin of the receptacle.
Fegatella conica developes from six to eight archegonia on
the lateral margins of its receptacle (PL XVI, fig. 6).
These archegonia are, at an early period, surrounded by the
receptacle, which is growing rapidly in breadth. The mass

THE HIGHER CRYPTOGAMIA. 1 L5

of the receptacle increases very considerably round the
base of each archegonium, so that these soon have the ap-
pearance of deep, almost cylindrical, cavities, sunk in the
under side of the receptacle (PL XVII, figs. 7, 8). The
fructification consists, as it were, of as many amalgamated
cornet-shaped masses of cellular tissue as there are
archegonia. The very considerable expansion of the cells
of these masses causes their margins, in half-developed
receptacles, to extend close to the point of origin of the
common fruit-stalk.

The archegonia of Fegatella resemble those of Rebouillia
in the early and extensive development of their ventral
portion. Like the great number of liverworts whose
archegonia have to live through the winter, they exhibit the
early duplication of the cellular layer surrounding the central
cell of the ventral portion, and the extensive growth in
thickness of the wall of the young calyptra after the occur-
rence of impregnation (PI. XVI, fig. S). The neck is pro-
portionately long.

The rudimentary fruit, when consisting only of a few
cells, may be very easily detached (PI. XVI, fig. 9). The
ladder-like arrangement of its cells, caused by the repeated
division of an apical cell by means of alternately inclined
septa, is uncommonly sharply defined. The growth of the
uppermost part of the young fruit in thickness, *. e. the
foundation of the capsule, commences at a very early period
(PI. XVI, fig. 10). The lower portion of the fruit-stem is
very slightly developed ; the formation of a knotty enlarge-
ment of its base is entirely suppressed. As observed by
Schmidel (' Icones plant.,' p. 121) and Bischoff, the stem
detaches itself spontaneously when the fruit is ripe from the
tissue in which it is inserted. The first archegonia of
Mar 'chantia polymorphs appear in like manner at the margin
of the young receptacle, usually eight in number, placed at
regular distances. Those at the hinder part of the recep-
tacle {i. e. turned away from the fore edge of the plant)
are developed, as in Rebouillia and Fegatella, much earlier
than those on the opposite part (PI. XV, figs. 11, 12).
Very soon after the appearance of the first archegonia new
ones are formed on the under side of the pileate receptacle,

116 HOFMEISTER, ON

and nearer to its centre, arranged in radial double rows
(PL XV, fig. 11). A phenomenon, of which traces are
seen in Rebouillia, is very strongly marked in Marchantia :
the underside of the margin of the receptacle is developed
at a very early period between each two archegonia into a
process extending downwards for a considerable distance,
whose form gradually passes from that of a hemispherical
wart to that of a long, cylindrical prolongation, curved
slightly inwards, with deep, longitudinal furrows on the
under side, in which rootlets lie concealed.

The archegonia of Marchantia polymorpka are large-celled,
the ventral portion being remarkably swollen at an early
period. A single layer of flat, tabular cells surrounds the
proportionably large central cell of the ventral portion,
which is attached almost immediately to the under side of
the receptacle. The neck of the archegonium, which in its
earliest youth is curved strongly upwards (PL XV, fig. 12),
is pointed directly downwards at the time when the apex
opens (PL XV, figs. 13, 14).

After the parting asunder of the cells of the apex, the
central cell of the ventral portion of the impregnated arche-
gonium enlarges very considerably. A free, oval cell entirely
fills its inner cavity. Its large central nucleus is very
plainly distinguishable as a clear vesicle in the thick
granular mucilage (PL XV, figs. 13, 14). The transforma-
tion of this cell into the rudimentary fruit is introduced by
the appearance of a much inclined longitudinal septum
PI. XV, fig. 15). The septa, which are formed at a later
period in the apical cell, diverge only very slightly from the
longitudinal axis of the fruit. T have but seldom and only
imperfectly succeeded in detaching the young rudimentary
fruit. It remains for some time spherical ; its cells soon
become very small by repeated cell- divisions.

After the first divisions of the primary cell of the rudi-
mentary fruit, the cells of the young calyptra double them-
selves by the formation of septa parallel to the outer surface.
A special covering has at an earlier period been formed
close round each impregnated archegonium. The ring of
bells of the under side of the receptacle which surrounds the
case of the archegonium protrudes outwards ; the protru-

THE HIGHER CRYPTOGAMTA. 117

ding portions are separated from the original cell-cavity by
transverse septa (PL XV, fig. 13). By repeated transverse
divisions of the apical cells of the membranous sheath, pro-
duced by septa parallel to the free margin, the young
covering grows in length (PI. XV, fig. 14). Its fur-
ther development, viz., the transformation of the cylin-
drical shape into that of a distended pitcher (PI. XV,
fig. 15), corresponds to that of the covering of Frullania
dilatata.

Close under the arched upper surface of the receptacle
of Marchantia, including the outer surfaces of the
upward-growing shoots of the lateral margin, numerous air-
cavities are formed, even before the first appearance of
the archegonia. They are formed in the same manner as
the air-cavities of the stem. At the first appearance of the
air-cavity one epidermal cell only detaches itself from the
underlying tissue of the receptacle (PI. XVI, fig. 17, un-
derneath, to the right). By repeated transverse division
of the mural rows of cells lying between the air-cavities,
the lid of the cavity is carried rapidly upwards. This
epidermal cell, which closes the air-cavity, forms itself into
a stomate. It divides by a septum perpendicular to the
outer surface, as is the case in the first stage of the
stomata of the upper side of vegetative shoots ; both
daughter-cells then divide by a septum at right angles to
the one last formed (PI. XVI, fig. 17, in the middle). The
four cells part asunder at their edges of contact, and the
air-cavities come into connexion with the outward air.
The four cells of which the young stomate now consists
divide repeatedly by transverse septa. The first partitions
thus formed are parallel to the upper side of the receptacle ;
the later ones, which are produced in the upper and under
of the newly formed cells, are strongly inclined either towards
or away from the passage which traverses the axis of the
stomate. The apex of the organ protrudes above the upper
side of the receptacle in the form of a conical wart, open at
the apex ; the base lies deep clown in the air-cavity
(PL XVI, fig. 7). The middle part of the canal, which
traverses the stomate, is strongly distended. In the mean
time the apical cells of the cellular walls, which separated

118 HOFMEISTER, ON

the individual air-cavities from one another, have also
multiplied considerably. A remarkable transverse ex-
pansion has preceded the repeated bipartitions (PI. XVI,
fig. 17, at the bottom, on the left side); the sides of the
cells are at an early period forced above the air-cavity, to
which they are contiguous. The process of the production
of those cells of the epidermis of the receptacle, which are
in connexion with the cellular layers separating the air-
cavities, consequently soon helps to form the lid of those
cavities, which at an earlier stage was represented only by
the young stomate or its mother-cell.

The base of the side walls of the air-cavities of Mar-
chantia soon produce moniliform chains of cells filled with
chlorophyll. In Rebouillia most of the cells of those walls
do not usually do more than project considerably, but
individual cells grow out into short, cellular rows. The
wralls of the air-cavities of the receptacle of Fegatella remain
for a very long time smooth and even.

The median component part of the fructifying shoot of
Targionia hypojphylla does not become changed into a
specially formed receptacle, but developes the archegonia at
once, the latter being from one to five in number (PI. XV,
fig. 21). The lower half of the archegonia is pressed into
the exceedingly narrow fissure, within which the lateral
wings of the fore edge of the fertile shoot confine the rudi-
mentary median part. The necks of the archegonia, which
are bent upwards, project from the fissure into space. A
considerable increase of the parts of the tissue adjoining
the archegonia in front commences even during the longi-
tudinal growth of the latter. At the junction of the
median shoot with the lateral wings of the fore edge,
above the point of attachment of the archegonia, the cellu-
lar layers expand and multiply vigorously in a longitu-
dinal direction ; their thickness is proportionate to the
development of the layer of air-cavities. Before the apices
of the archegonia open, a flat covering is formed, which
exceeds the archegonia in height, and which unites the
approximated lateral portions of the fore edge into one
surface. The separation of the upper side of the stem into
the layer of air-cavities and the epidermal layer takes

THE HIGHER CRYPTOGAMIA. 119

place within this covering (PI. XV, fig. 21). At the same
time broad, fleshy, cellular masses, concave above and
within, rise out of the angles between the median shoot
(which bears the archegonia) and the lateral wings. They
amalgamate with one another, and by their upper margin
they unite with the above-mentioned covering. Thus, there
is formed a blunt, triangular envelope, enclosing the lower
part of the archegonia, from the narrow three-sided opening
of which the apices of the unimpregnated archegonia pro-
trude (PI. XV, fig. 21). The rather thin walls of the enve-
lope, which are turned downwards, consist of homogene-
ous cellular tissue.

When a rudimentary fruit is formed in an archegonium
the envelope enlarges with wonderful rapidity, especially by
expansion of its cells. It very soon entirely encloses the
impregnated archegonium. The cells adjoining the mouth,
which continues very narrow, grow out into short papillae.

The archegonia are slender, almost cylindrical. The
cropped appearance of the apex, which occurs also in the
archegonia of the Marchantieae, is seen with remarkable dis-
tinctness (Pl.XV,figs. 22,23). The cells of the ventral portion
double themselves at an early period by septa parallel to the
circumference. The inner cells adjoining the central cell be-
come filled with granular matter, as in Pellia (PL XV, fig.
22). Immediately after impregnation the cells of the incipient
calyptra multiply very rapidly, so that, as in Rebouillia,
the central cell becomes a fusiform cavity, in which the
mother-cell of the rudimentary fruit lies free (PL XV,
fig. 22).

The rudimentary fruit in its earliest youth is narrowly
spindle-shaped, composed of two double rows of cells (PL
XV, fig. 24, detached; fig. 23, enclosed by the calyptra). The
growth in thickness begins much earlier at the upper end
than at the lower (PL XV, figs. 23, 25). The latter pene-
trates deeply into the tissue of that portion of the stem
which bears the impregnated archegonium, and which has
become transformed by active and repeated division of its cells
into a conical, cellular mass. The lower end of the rudi-
mentary fruit, which is originally of a pointed, conical form,
changes gradually into a spherical enlargement by trans-

120 HOFMEISTER, ON

verse expansion and subsequent repeated bipartition of
the cells of its circumference (PI. XV, fig. 26).

The arrangement of the spore-mother-cells and of the
elaters in Targionia, and also, it would seem, in the Marclian-
tieae, is very much the same as in Fossombronia pusitta.
At the time of the differentiation of the two kinds of contents
of the capsule, the cells destined to form the elaters are
hardly perceptibly longer and thinner than the future
mother-cells of the spores (PL XV, fig. 29). The elaters
and spore-mother-cells lie across one another somewhat
like the chlorophyll-cells and the air-cells of the leaf of
Sphagnum. A remarkable longitudinal expansion of the
elaters first occurs when the prominences of the inner wall
of the spore-mother-cell begin to be seen (PL XV, fig. 30).

The antheridia of the Marchantiese are, as is well
known, united in large numbers on the upper side of pecu-
liarly formed shoots, and enclosed in flask-shaped cavities
of the tissue.

The first stage of development of these shoots in Marchan-
tia polymorpha exactly resembles the first rudiments of the
head of the inflorescence. Here as there the forward, upper
portion of the narrow, almost cylindrical shoot becomes
developed considerably in breadth, protruding beyond the
lower, stem-like portion, like the pileus of a fungus. A
number of cells of the upper side of this disc, which is
slightly convex above and strongly so beneath, protrude
outwards in the form of papillae ; between them the epi-
dermis detaches itself from the underlying tissue. The
shortly cylindrical cellular processes, the first rudiments of
the antheridia, are outgrown by the cells surrounding them,
and are sunk down into circular cavities of the upper
surface. This arises from the rapid multiplication of the
cells of the circle which bears the detached fragments of the
epidermis, which multiplication is caused by rapid and
frequently repeated division of these cells by means of
septa parallel to the surface of the antheridial disc (PL XV,
fig. 16). The above process commences in the middle
point of the young antheridial disc, and progresses from
thence to its growing margin.

The mother-cell of the antheridium assumes the form of

THE HIGHER CRYPTOGAMIA. 121

an elongated, oval cellular mass, consisting of four rows of
cells (PI. XV, fig. 16). This arises from frequently re-
peated division of the apical cell by means of alternately
inclined septa, and by the production of radial longitudinal
septa in the cells of the second degree. The cells of one
of these rows, with the exception of the two at the base,
and the one next to the apex, divide by septa parallel
to the longitudinal axis of the antheridium, and cutting the
side walls of the mother-cells at an angle of 45°. The
antheridium now consists of a short, central string of cells,
surrounded by a single layer, the cells of which are
arranged in successive sets of four cells of equal height.
The further development, like the preceding, corresponds
with that of the antheridium of Anthoceros and Pellia,
with this distinction, that the multiplication of the cells in
the direction of the longitudinal axis, exceeds that in the
direction of the. thickness. The ripe antheridium is oval.
The apices of the cellular masses which arise between
the antheridia expand considerably in breadth as soon as
they have outgrown the antheridia. They consequently
soon close together over the antheridium, so as to form
narrow passages, hardly perceptible from the outside. The
cell which covers the air-cavity develops itself into a
stomate, exactly in the same way as the median cell of the
covering of the air-cavities on the upper side of the recep-
tacle (PI. XV, fig. 1G). The cells adjoining this cell divide
by slightly inclined longitudinal septa parallel to the axis
of the stomate. The inner of the cells thus produced,
which form a ring round the stomate, take part in the
formation of the covering of the air-cavity, expanding at
the same time in breadth. In the air-cavities in the
middle of the antheridial disc these cells divide frequently
by longitudinal and transverse septa perpendicular to the
outer surface. The cells of the base of the disc grow into
the expanding air-cavities, and form chains of cells filled
with chlorophyll. When the antheridia are ripe, the cells
of the apical, covering layer separate from one another, the
internal mucilage, swarming with thousands of active,
motile spermatozoa, is forced through the narrow canal at
the apex of the antheridia which opens externally, and ap-

12.2 IIOFMEISTER, ON

pears in drops of considerable size upon the upper surface
of the antheridial disc. The spermatozoa, which are hardly
half as large as those of Pellia, consist of a delicate
thread, slightly thickened at one end, and drawn out into
a thin long process at the other. I could perceive no trace
of lateral cilia.*

I have only been able to examine the antheridia of
Rebomllia hemispherica when fully developed. They are
imbedded, as Eischoff's beautiful observations have shown,-r
in half-moon-shaped cushions, which appear superimposed
upon the median line of vegetative shoots, usually upon
those which bear a fruit-receptacle. As the outside of these
cushions often bear rudimentary leaves, it appears to me
probable that these cushions may be considered to be weakly
developed shoots, resembling to some extent, in their deve-
lopment, the portions of the stem of Pellia which bear
archegonia (PI. XVI, fig. 17). The antheridia are pro-
portionably large, surrounded by flask-shaped cavities. In
the youngest which I have examined there was still to be
seen the covering layer of tabular cells (PI. XVI, fig. 17),
which, at a later period, is entirely supplanted, so that a
membranous sac alone encloses the cells which produce the
spermatozoa. The mouth of the antheridial cavities is
not often on the level, like that of Marchantia polymorplia
(PI. XVI, fig. 17). It more frequently protrudes to a consi-
derable height, in the form of a thick, conical point, like the
antheridial envelopes of Riccia. The tissue of the anthe-
ridial cushions consists of very large cells, with transparent
fluid contents.

The history of our knowledge of the Marchantiese is
most fully treated in Bischoff's work, already so often cited,
and in the fourth part of the ' Naturgeschichte Euro-
paischer Lebermoose,' by Nees von Esenbeck. Except this
volume, I know of no connected treatise on the develop-
ment of the March antiese since the almost contemporane-
ous appearance of BischofT's and Mirbel's \ large works.

* Compare Thuret, ' Ann. d. Sc.,' iii ser., torn. 3, pp. 13, 14.
f ' N. A. A. C. L.,' vol. xvii, pi. lxix, f. 4, 6, 7.

% " Rechcrehes sur la Marchantia polymorplia," 'Mem. de 1'Acad. des Se. de
1'Iiist. de France,' vol. xiii.

THE HIGHER CRYPTOGAMIA. 123

Many of the most interesting specialities are to be found in
Gottsche's two writings above referred to. The above
investigations of Mirbel and Bisclioff are so generally
studied and known that it would be superfluous to give
even a short summary of the valuable results obtained by
them. Good representations of the fruit and perianth of
Marchantia potymorpha are to be found in Micheli's ' Gen.
PL/ p. 2, and in Dillenius's ' Hist. Muse.', pi. xxviii,
figs, m, 71, who also figures the germination of the gemmae.
Micheli considered the male and female plants as different
species ; the relation of the two was first noticed by
Hupp ('Flora Jenensis,' ii, 276), then by Dillenius (1. c,
p. 524), and with certainty by Linnaeus (SP. PL. 1137).
Our present more accurate knowledge of the Marchantieae
dates from the publication of Schmidel's observations
('Icones pi.,' ed. ii, p. 109 M. polymorplia ; p. 120 Fega-
tella conica; p. 133 Preissia commutata). Schmidel
isolated the antheridia, and pointed out their mode of attach-
ment to the tissue supporting them ; he gave an accurate
figure of the structure of the receptacle, and described the
spontaneous detachment of the fruit- stalk of Fegatella conica
from the tissue of the mother-plant. Hedwig (£ Theoria
generationis,' ed. ii, 1798) distinguished the enveloping
cellular layer of the antheridia (p. 176), and found that
in the young fruit the young perianth did not reach
to the height of the mouth of the archegonium (p. 177).

The object of Mirbel, in his remarkable work on Mar-
chantia polymorpha ('Mem. Acad, des Sciences de l'lnst.
de Prance/ xiii, 1835) was to investigate fully the
history of the development of this plant in all its speciali-
ties. This object was only imperfectly attained. Mirbel
observed the germination of the spores. He came, how-
ever, to the erroneous conclusion that the newly added
cells were produced on the outside of the existing cells
(I.e., p. 347). This error arose from the circumstance
that in young multicellular germ-plants which are fur-
nished with only one rootlet, the cell out of which the root-
let is formed is very similar in shape and size to the
germinating spore, whilst the latter is still unicellular, but
when it has already developed a rootlet. His view of

124 HOFMEISTER, ON

the origin of the quadrangular stomate upon the vegetative
shoots is to some extent erroneous, for he assumed such
origin to lie in the disintegration of one four-sided cell,
surrounded by four epidermal cells, which (four-sided)
cell is, in reality, the mother-cell of the cells which enclose
the stomate, and which afterwards separate from one
another. H. von Mohl commented upon this error in the
' Linnsea' (1838) and in his ' Vermischte Schriften/ p. 25:2.
Mirbel's representation of the origin of the stomate sur-
rounded by more than four cells is, on the other hand,
quite natural (1. c, p. 356).

With regard to the receptacles of the gemmae, Mirbel
believed that, at the time of their appearance, the super-
ficial cellular layer of the flat stem became detached from
the underlying tissue, and separated into converging
teeth, which soon constituted the margin of the receptacle.
Mirbel has rightly apprehended the unicellular, earliest
state of the gemmse (1. c, p. 350^ ; his notion of the con-
temporaneous metamorphosis of the contents of the uni-
cellular gemmae into a multicellular tissue filling the cell
was confirmed by Niigeli in 1845 (' Zeitschrift f. wiss.
Bot.,' ii, p. 150). Mirbel's investigations of the germina-
tion of the gemmae of Marchantia are of especial interest.
lie showed that that surface of the gemmae which happens
to be in contact with the ground develops rootlets, whilst
the other one forms the upper surface by development of
stomata and air-cavities ; but that, twenty-four hours after
being sown, and when only a few rootlets have grown
out of the under side, the upper and under surfaces of
the future plant have already become permanently dif-
ferentiated. When gemmae, which had been sown for this
short period, wTere reversed, rootlets grew from that side,
which having been formerly the upper, had become the
under surface, whilst those rootlets which had sprung
from the quondam upper, then the under surface, con-
tinued to grow, and bending themselves downwards, pene-
trated the soil. During the further growth of the gemma?,
however, each of the elongating lateral halves effected a
semi-revolution around its axis, so that the surface which
had been formerly the upper one again became the upper

THE HIGHER CRYPTOGAMIA. 125

surface of the newly developed portions. In cases where
obliquely incident light intersected the smaller diameter of
the inverted gemmae, the younger portions of the latter
bent themselves simply backwards, so that the original
upper side was again turned to the light, and only rested
upon the soil by the one reflexed end.

The under side, which by inversion had become directed
upwards, never developed stomata, not even at the points
directly exposed to the light ; on the other hand, when
kept in the shade and sufficiently moist, it sent out roots
in every direction, and as it advanced in age exhibited pro-
minent ribs (1. c, p. 355). Mirbel thought that the cell-
multiplication in the interior of the gemma?, was an inter-
polation of new cells between those already present (1. c,
p. 352). He has not discussed in detail the mode of rami-
fication of the Marchantieae, although the inquiry into this is
closely connected with the investigations as to the mode of
development of the gemmae. Even at a still later period,
up to the present time, this ramification has generally been
described as dichotomous (as, for instance, by Nees v.
Esenbeck, ' Naturgesch. Europ. Lebermoose ' iv, (1S38)
p. 83), whereas, in point of fact, it represents a Dichasium.
We are indebted to Mirbel for very accurate accounts of
the structure of the developed fructification, especially of
the relation of the longitudinal forks of the stem, which are
traversed by the rootlets, to the pileate expansion which
bears the reproductive organs (1. c, pp. 346, 376). Mirbel
was least successful in his investigations of the structure
and development of the organs of sexual reproduction ; his
figures are certainly beyond all comparison more elegant
and satisfactory than those of Schmidel and Hedwig, but
in the knowledge of the more important circumstances he is
not really a step in advance of the observers just named
(1. c, pp. 377 — 381). Mirbel's investigations of the develop-
ment of the spores and elaters were of great scientific im-
portance, the more so because, in conjunction with Mold's
contemporaneous works on the same subject, they gave an
impetus to the more accurate investigation of the visible
processes of cell-formation and cell-multiplication. Mirbel
pointed out the division of the contents of the spore-mother-

126 H0FME1STER, ON

cell into four masses, each of which becomes a spore, and
also the origin of the elaters, out of a previously thin-coated
elongated cell (1. c, pp. 371, 382). In a treatise more par-
ticularly devoted to systematic questions relative to the
Marchantieae, Bischoff (' Nova Acta A. C. L.,' xviii, 1835)
has communicated some interesting results ; he proved
that the presence of male plants of Imnularia vulga-
ris \% necessary for the development of the fruit (p. 925) ;
he pointed to the simple nature of the structure of the first
shoot of the germinating spore in comparison with that of
the shoots of the fully developed plant (p. 953). He lias
repeatedly and emphatically dwelt upon this point, and has
endeavoured to distinguish these first shoots (as a prothal-
lus) from the later ones (' Handb. Bot. Term./ ii, p. 733 ;
'Bot. Zeit.,' 1853, p. 113), starting manifestly from the
supposition that the formation of a prothallus is peculiar to
the order Muscincae, and that it must, therefore, be proved
to exist generally in all liverworts (see BischofFs definition
of the Muscineae in CN. A. A. C. L./ xviii, p. 958). Both
Gottsche and myself have proved that there is no essential
difference between the first shoot of the germ-plant and
the later shoots ('Botan. Zeit.,' 1858, Supp., p. 45).

This difference of opinion can give rise to no real con-
troversy. The formation of a prothallus is a universal phe-
nomenon in the embryonal life of plants. The development
of the germinal vesicle of the phaenogams into the embryo,
of the germinal vesicle of the vascular cryptogams into the
rudiment of the leafy plant, and of the germinal vesicle of
the Muscineae into the fruit all commence with a kind of
cell-multiplication, which, at least during the first process
of division, differs from the later stages of development.
The first, at least, of the permanent cells thus formed does
not enter into the composition of the mass of the organ
which is to be constructed ; very frequently it dies. The
same law prevails in the germination of the spores of ferns
and of the Muscineae. In the leafless Jungermannieae, the
Riccieae, and the Marchantieae, however, the boundary
between the prothallus and the developed plant is not, as
Bischoff considers, to be looked for at the point where the
second shoot is attached to the first, but at the point where

THE HIGHER CRYPTOGAMIA. 127

the primary, atypical divisions of the spore-cell terminate,
and the regular arrangement of the cells of the first shoot
commences. As far as present observations extend, this
point is generally only a few cells distant from the hinder
end of the germ plant.

Few works upon the Marchantieac have appeared since
those of Mirbel and Bischoff. Gottsche has given a very
accurate account of the germination of Preissia commuted a
('Nova Acta A. C. L.,' xx, p. 388) ; Gronland has pub-
lished some observations upon the same subject, and upon
the germination of Marchardia polymorpha and Lunularia
vulgaris ('Ann. d. Sc. Nat.,' iv ser., vol. i, 1854, p. 22);
and lastly, Iienfrey has written upon the development of
the spores and elaters of Marchantia polymorpha ('Trans.
Linn. Soc.,' vol. xxi). The latter paper contains the
important observation that the interior of the young capsule
is filled with elongated, closely packed cells. A portion of
these radiating cells consists of narrow, thin tubes, tapering
at both ends ; these are the young elaters ; the wider cells
are the primary mother-cells of the spores. These wider,
elongated cells are divided by transverse septa into rows of
cubical cells, the spore-mother-cells. Sometimes longi-
tudinal division also takes place in some of the rows of
cells thus formed (1. c, p. 107). The process is, therefore,
very similar to that which I have described in Fruttania
dikdata. The development of the spores of Marchardia
polymorpha affords very little opportunity for the study of
the processes of cell-multiplication, on account of the
sensitiveness of the membrane and of the contents of the
mother-cells. It is quite conceivable that Henfrey might
have failed to see nuclei during the examination of the cells
in water or iodine (1. c, p. 109).

Motile spermatozoa were first observed in Marchantia
by Unger (< N. A. A. C. L.,' xviii, p. 791, 1837). In
his figures (1. c, pi. lvii, fig. 4) he represents correctly
the relation of the two oscillating cilia of the fore end of the
spermatozoon to the body of the latter, but without noticing
that the duality of these cilia is normal. Meyer also
(' Wiegman's Archiv,' 1838, i, p. 212) believed the sper-
matozoa of Marchantia to be furnished with only one long

128 IIOFMEISTER ON THE HIGHER CRYPTOGAMIA.

" tail," an unfortunate expression, inasmuch as the filiform
portions take the lead when the spermatozoon is in motion.
Thuret's figures of the spermatozoa of the Marchantieae are
very accurate ( ' Ann. cl. Sc. Nat.,' hi scr., xvi, pi. xii ;
Marchantia, Fegatella, and Targionia).

CHAPTER VI.

MOSSES.

The stems of mosses grow by continually repeated
divisions of the blunt, conical, apical cell. This cell is
pointed beneath ; the division takes place by means of
septa inclined in different directions. All mosses are
alike in this. The form of the terminal bud is very various ;
it is narrowly pointed in Sphagnum and Bacomitriwm
ericoides (PI. XXI, fig. 19); it is blunt in Phascum and
in many others ; hemispherical in Hypnum ; and very
slightly arched in Polytrichum and Dicranum scoparium,
where it is, in fact, almost a level surface, upon which the
youngest leaves are arranged concentrically.

The apical cell of the stem of Sphagnum is pointed be-
neath, where it has three surfaces ; and this three- sided
pyramid is deeply imbedded in the adjoining next older
cells of the end of the stem. These cells were separated
from the inner cavity of the terminal cell by the formation
of septa traversing that cavity. Each new septum which
is produced in the apical cell is parallel to one (and that
one the oldest) of the lateral surfaces, and cuts the two
others. The newly formed cell of the second degree has
the form of a body with rhombic fore and hind surfaces
and with four rectangular lateral surfaces, one of which,
the smaller one (the free outer wall of the cell), is slightly
arched. The successive septa produced in the apical cell
are therefore arranged spirally, and the spiral is normally
a left-handed one, in accordance with the arrangement of

9

130 HOFMEISTER, ON

the leaves.* Each cell of the second degree divides very
soon after its separation from the apical cell, by a septum
at right angles to the longitudinal axis of the stem, which
septum cuts the free outer wall, and also that lateral wall
of the cell which is turned towards the apical cell.

* The first correct account of the cell-multiplication in the outermost apex
of the stem of Sphagnum was given by Niigeli ('Pflanzen. physiol-Unter-
suchungen,' i, Zurich, 1855, p. 76). I had previously ('Vergl. Unter-
suchungen,' p. 60) erroneously conceived the process to consist in the repeated
division of a two-surfaced, pointed, apical cell, by means of septa alternately
parallel to either of the two lateral surfaces. The origin of tiiis error was as
follows : — When the arched apex of a very slender paraboloidal cellular body
consists of a single terminal cell (as is the case with the ends of the stein of
Sphagnum and Equisetum), a portion of the lateral edges of the apical cell will
usually be the only part clearly visible when the body is viewed from above.
The edges of the neighbouring cells of the second degree will not be seen.
These edges form arcs, the curvature of which is greater in proportion to the
size of the cells of the second degree, i. e. in proportion to the size of that por-
tion of the terminal cell which is cut off to form the cell of the second degree.
If the edges of the apical surface of the terminal cell of the bud extend so deep
down that at the spot where each two intersect the sides of the bud possess a
high degree of inclination, then, when the body is viewed from above, the
middle part only of each edge of the apical surface can be clearly seen.

When the apical cell has the form of a three-sided inverted pyramid, with its
apical surface highly arched, and divides by septa arranged in a continuous
spiral order, and parallel to one of the lateral surfaces, then one of the edges of
the apical surface must, immediately after each division, be considerably shorter
than the two others. This fact is more clearly perceptible in proportion to the
size of that portion of the cell which goes to form the cell of the second degree.
In a system of similar spherical triangles, with a common centre, constructed by
drawing successively within each triangle arcs parallel to each one of its sides,
it will be found that one of the three arcs of each successive triangle is con-
siderably shorter than the other two, the difference being greater in proportion
to the curvature of the arcs, and to their distance from the respective parallel
sides of the next outer triangle (see the Diagram, PI. XVII, fig. 5*). When
the length of the arcs exceeds 90° ; when the length of the transverse diameter
of the outer surface of a cell of the second degree amounts to one half of the
diameter of the cell of the first degree from the division of which it originates ;
and lastly, when at the moment of division (by virtue of the inuate growing
power of the plant) the form of the apical surface of the cell of the first degree
is not that of an equilateral, but of an isosceles spherical triangle, then it may
happen that the points of intersection of the two larger arcs with the third
(very short) arc may fall quite outside the apical, vaulted surface of the organ,
when the latter surface is viewed under the microscope directly from above.
These remarks apply almost exactly to the apices of the stems of Sphagnum and
Equisetum, if observed immediately after the occurrence of division in the apical
cell. A figure of the upper surface of the terminal cell is then obtained, which
is strikingly similar to the apical aspect of the two-surfaced segment of a
spheroid (PI. XXII, fig. 4). Now, since in other instances (as in the apices of
the stems of liverworts, of Selaginella and of certain ferns, and in the organs
of fructification of mosses &c.) I had frequently ascertained that the multipli-
cation of the apical cell undoubtedly took place through division by means of

THE HIGHER CRYPTOGAMIA. 131

The cell of the second degree is thus divided into an
upper daughter-cell, with three-sided fore and hind surfaces,
and an under, four-sided cell (PL XVII, fig. 2). The free
outer wall of the former forthwith becomes arched outwards,
and is recognisable as the rudimentary cell of a leaf. The
latter (the lower cell) divides by means of longitudinal
septa, alternately tangential and radial to the axis of the
stem, which division continues until the completion of the
full number of the cells of the portion of the stem in
question. There is no very great regularity in the suc-
cession of these divisions. Sometimes one, sometimes the
other, occurs first ; frequently one step of the ordinary suc-
cession is passed over, and made good at a later period. In
every case, however, one phenomenon is constant — at a point
near the end (of the stem), about three cells downwards
from the apical cell, the number of the cells of the circum-
ference of the young stem is eight. An inequality in the
multiplication by radial longitudinal septa of the cells of
the third degree also occurs regularly ; one of these cells in
each zone of the stem must lag about one division behind
the two others. For if this multiplication in the cells of
the third degree were uniformly active, it would follow that,
inasmuch as three cells of the third degree must occur in
each transverse section of the stem, the number of cells of
each girdle of the outer surface of the stem must be a
multiple of three.

A transverse section of the perfect stem usually exhibits
a number of peripheral cells which is a multiple of eight.

septa inclined alternately in only two opposite directions, I was led to believe
that I must necessarily assume the same to be the case in Sphagnum and Equi-
setum, where 1 observed the pointed apical cells of the stem-bud had the
appearance of being two -surfaced. The cases of three-sided apical cells
which came under my observation, and of which I have given figures in
pi. xix, fig. 7, of the ' Vergleicheude Untersuchungen,' I considered to be
instances of a mode of growth which caused a change in the form of the
apical cell between the period of each two divisions. Later observations
have convinced me that Nageli's representation of the mode of increase of
the apical cell of the stem of Sphagnum, and Cramer's account of the similar
process in Equisetum, are correct. From this error there necessarily arose,
in the case of Sphagnum, an additional one, viz., in the account given of the
further division of the cells of the second degree, and in the statement that
the rudimentary cells of the leaves were derived from these latter cells,
which error I have corrected in the text above.

132 HOFMEISTER, ON

111 slender branches, especially those which hang down-
wards, the bark consists very regularly of only eight longi-
tudinal rows of cells. In the younger parts of the bud
the axile cells of the stem are more elongated longitudinally
than the peripheral cells, a circumstance which has a
remarkable influence upon the slender form of the end of
the stem. The arrangement of the cells of the interior of
the stem into triangular plates, inclined inwards to the
axis of the stem, arises from the fact that all the cells of
the third part of a transverse section of the stem are
derived from a single cell of the third degree. Each of
these plates is higher by a portion of the length of a cell
than the adjoining plate on one side of it, and is exceeded
by the same portion of the length of a cell by the similar
plate on the other side of it. The difference of height of
two such cellular plates is almost always less than half a
cell, a circumstance from which it must be concluded that
the elongation of the cells of the stem preponderates in
their upper portions. The above-mentioned arrangement
is most clearly seen in a perfectly axile longitudinal section
of a Sphagnum bud, made at some distance from the apex ;
if the section deviates only slightly from the longitudinal
axis of the bud, the arrangement is partially or entirely
"imdistinguishable.

In all the cells of the periphery of the stem (with the
exception of the cells of insertion of the leaves) a transverse
division occurs a short time before, or contemporaneously
with, the termination of the cell-multiplication of the end
of the stem, in a radial direction (PI. XVII, figs. 1, 7).
This multiplication does not continue in the cells of the
interior of the stem, which are elongated, instead, during
its continuance, to about double their former length ; by
this means the short-celled bark is differentiated from the
long-celled axile-tissue. The multiplication of the stem-
cells in the diametral direction is caused by the division
of the slightly elongated cells of the interior of the
stem, by means of septa tangential to the axis of the stem,
alternating with divisions by radial longitudinal septa.
The number of these cells in the transverse diameter of
the stem increases tenfold from the place of insertion of

THE HIGHER CRYPTOGAM I A. 133

the youngest (already multicellular) leaf, to the place
where the stem ceases to increase in thickness (PI.
XVII, fig. 1). This cell-multiplication does not, how-
ever, occur exclusively in a specific group of cells, such as
is found in many vascular plants somewhat in the form of
a cylindrical envelope. It is no doubt true that the cells in
which division especially occurs are those of a conical
envelope lying underneath the outermost cellular layer of
the conical mass of cellular tissue. But the cells of the
inner layers are by no means passive (PI. XVII, fig. 1).
During these processes the cells of the outer surface divide
by radial longitudinal septa, and the cells of more vigorous
shoots also by tangential longitudinal septa, so that the
above peripheral cellular layer becomes transformed into a
double, triple, or quadruple layer of cells (PI. XVII, fig. 1).
In more slender shoots the latter form of cell- division is
suppressed : the cells of the periphery of the stem certainly
increase in number, by the formation of radial longitudinal
septa, whilst they keep pace with the increase of the peri-
phery of the axile cellular string ; the bark, however, re-
mains, for a time at least, a simple cellular layer (PI. XVII,
figs. 7, 9). The basal cells of the leaves, which are buried
to a certain depth in the tissue of the stem, and which are
easily recognisable by their peculiar tabular, flattened shape,
present in their ends, which are turned inwards, certain
indications from which it can be determined whether a
multiplication of the peripheral cells of the bark of the
stem has taken place or not (PI. XVII, figs. 1, 7, 8, 9).

Whilst the growth in thickness of the stem is thus in
course of completion, its longitudinal growth is at a
stand-still. It commences with increased activity at the
spot where the conical form of the end of the stem passes
into the cylindrical form of the older portion. All the
cells become extended to at least twelve times their former
length, and during this elongation one more final process
of cell-multiplication takes place in them. The cells of the
interior of the axile string are often (although not with any
regularity) divided by transverse septa (PI. XVIII, fig. 8).
The cells of the periphery of this string divide still oftener
by radial and tangential longitudinal septa. They become

134 HOFMEISTER, ON

very narrow and elongated (PI. XVII, figs. 8, 9) . Lastly, the
cells of the bark, in all tolerably vigorous shoots, divide
once more by tangential longitudinal septa, and in all cases
very frequently by transverse septa (PL XVII, fig. 8).
The bark thus becomes a stratum, consisting of from two
to four layers of cells. In slender shoots this duplication of
the cellular layers of the bark does not take place ; trans-
verse divisions only occur in their cells, so that even the fully
grown bark consists of only one layer of cells.

A considerable thickening takes place in the walls of the
cells of the axile tissue of the ends of the stems of fully formed
shoots, whose longitudinal growth remains dormant from the
end of autumn until the following spring, and whose densely
crowded lateral shoots form a capitate accumulation round
the end of the stem. This thickening is observable in a
transverse section, when made about ten cells underneath
the terminal bud. The thickened cell-membranes exhibit
delicate pits (PL XVII, figs. 9, 9 h), which bring to mind
those of the Coniferae, inasmuch as they are usually
(not always) arranged in longitudinal rows.* There are
not any lenticular air-cavities between the ends of two con-
tiguous pits j the ends are divided from one another by a
thin, apparently homogeneous, membrane. The pits, when
seen from the surface, exhibit within their circumference a
narrow oval, but this appearance is probably caused by an
interference of the rays of light incident from beneath.
During the final longitudinal growth of the stem, during
the remarkable expansion of the axile tissue of the inter-
nodes (which expansion is rarely accompanied by a trans-
verse division), the thickening of these cell-membranes for
the most part disappears. In old stems the membranes of
the middle cells become rather thin again, and less brittle
than in the younger portions. It is now difficult to dis-
tinguish any traces of the pits, which at an earlier period
were so distinct. They have now the form of short, oblique
fissures. The above-mentioned peculiar thickening of the
cell-membranes only extends a short distance into the axile

* Figures of these pitted cells, agreeing with those previously published by
me, have also been given by 'Schimper, M6n. pres. p. div. savants,' xv, pi. iv,
f.4.

THE HIGHER URYPTOGAMIA. 135

tissue of the thin, lateral shoots. No trace of it is to be
found in the innovations* which are developed from the
ends of older, thinner, lateral shoots, and which, growing
rapidly in length and thickness, ultimately exactly resemble
the principal shoots in their mode of vegetation. On the
other hand, after the completion of the final longitudinal
expansion, a different mode of thickening occurs regularly
in the elongated cells of the axile tissue of these thin-
ner shoots, and also in that of the thick, principal shoots
and of the lateral shoots. After the completion of this
thickening the cell- membranes appear thick and indis-
tinctly stratified, their colour being yellowish-brown or
greenish brown, and sometimes very intense. This thick-
ening is most highly developed in the narrowest peri-
pheral cells of the axile cylinder ; it diminishes rapidly
in the wider, median cells.

When, from the arching outwards of its free surface, the
rudimentary leaf-cell is recognisable as the mother-cell of
the leaf, it embraces rather more than a third part of the
circumference of the stem (PL XVII, figs. 3, 4, 5). At
this period it still lies on the immediate boundary of the
apical cell of the tip of the stem (PI. XVII, fig. 2).
When viewed from above it is clearly seen that the tan-
gent of its free outer margin is parallel to the tangent of
the arc which is represented by that one of the lateral edges
of the apical surface of the terminal cell of the tip of
the stem which is turned towards the rudimentary leaf-
cell (PI. XVII, figs. 4, 5). If, now, the successive divisions
of the terminal cell were such that each third wall were
parallel to the third last one (as in the diagram, PI. XVI, fig.
bh), it would follow that, inasmuch as each cell of the second
degree produces a leaf, the leaves must be arranged under
one another on the stem, in three exactly parallel, longi-
tudinal rows. Accurate examination, however, of a termi-
nal bud shows that even in the youngest portions of the bud
this is not so. Even here also the youngest leaf- rudiments
have the arrangement which is characteristic of a later

* Scbimper, 1. c, pi. xvi, f. 1.

136 HOFMEISTER, ON

period, viz., that of a spiral, usually a left-handed one,
with divergenee represented by the fractions |, §, or ^.*
This circumstance can only be accounted for in two ways.
It is possible that, contemporaneously with or immediately
after, the formation of each leaf, a certain twisting of
the portion of the stem beneath it might occur. This
assumption, however, is negatived by observation. It is
easily seen that even the two youngest leaves of the bud
have always the same divergence as the older ones (PI.
XVII, figs. 3, 4, 5). The only other possible process is
that the apical cell of the stem may change its form between
each twro divisions in such a manner that each cell of the
second degree, which is cut off from it by the formation
of a septum parallel to one of itsjateral surfaces, is with-
drawn from the next previously formed similar cell by so
much of the circumference of the stem as is equal to the
distance of each leaf from the next youngest leaf beneath it.
Observation shows that both immediately before and imme-
diately after each division, the apical surface of the terminal
cell has the form of an isosceles triangle (PI. XVII, figs. 4,
5). The change of form of the cell, therefore, must arise
from the fact that its increase in size, after division, takes
place more particularly in a direction perpendicular to the
new wall formed by the division ; the youngest edge of the
apical surface, which immediately after division represented
one of the legs of the isosceles triangle, becomes, until the
next division, relatively the shortest side ; it forms the base
of the triangle, which, by the greater elongation of the two
other sides, has become again isosceles, but which deviates
to the extent of the angle of divergence of the phyllotaxis
from its previous position. The conclusions necessarily to

* A. Braun ('Nova Acta, A. C. L.,' xv, p. 279) and Schimper (1. c, p. 28)
agree in representing the phyllotaxis on the middle of the stem of Sphagnum
as having § divergence. I have previously spoken of f as the normal
arrangement ('Vergl. Unters./ p. 61), and I find this confirmed by subsequent
observations of the median shoots (PI. XVIII, fig. 5) of vigorous innovations
and of germ-plants. Doubtless the | arrangement also often occurs, of which I
myself have figured an example (PL XVII, fig. 4), but, however frequent, I find
it much less common than the other. Nageli also found the f and T53 ar-
rangements more frequent than the f. (' Pfianzen-physiolog. Uutersuchunoen,'
i, Zurich, 1855, p. 77.)

THE HIGHER CRYPTOGAMIA. 137

be drawn from the position of the youngest leaves, and
their relation to the apical cell of the stem in Sphagnum,
lead to the same results which I had previously arrived at
from direct measurement of the sides and angles of the
three-sided apical cells of the steins of ferns.* In Sphagnum
the object is not fitted for direct measurement ; the steep
inclination of the arch of the apical surface renders the
accurate determination of the length of its edges impracti-
cable. It is worthy of mention, however, that in the apical
cells of Sphagnum- stems, with f phyllotaxis, the apical angle
of the triangle is visibly much more acute than in stems
with | or T53 phyllotaxis. Probably in Sphagnum, as in
ferns, the change of form which the terminal cell under-
goes between two divisions does not depend upon a capa-
city for change of form innate in the cell alone, but is
caused by the definite expansion of the cells of the second
degree adjoining the apical cell.

The youngest conditions of lateral shoots which have
come under my observation have the form of hemispherical
arched cells, which are situated on the outer surface of the
terminal bud, at a distance of three or four cells in a
straight line from the apical cell, near the left margin of
the third or the fourth leaf, and above the middle line, in
the first case of the sixth, in the second case of the seventh
leaf f (PI. XVIII, figs. 16, 17). When a longitudinal sec-
tion of a principal shoot is made through the longitudinal
axis of the median shoot, and through that of a young-
lateral branch, it is clearly seen that the place of attachment
of the young lateral branch, together with the cortical cells
which lie between it and the next lower cell, occupies a
portion of the outer surface of the stem exactly as large as
that occupied by the insertion-cell of a leaf together with
the cells of the tissue of the stem which are produced from
the same cell of the second degree as the insertion-cell;
one of the oblique rows in which the elongated cells of the
interior of the stem are arranged reaches up to the place of
attachment of the branch (PI. XVII, fig. 1; PI. XVIII, figs.

* 'Abhandl. Kon. Sachs. Ges. d. Wiss.,' v, 642. I shall return to this subject
hereafter in speaking of the development of ferns.

f Considering the leaf as viewed from the outside and from beneath.

138 H0FME1STER, ON

16, 17).* This circumstance justifies the conclusion that at
the commencement of the formation of a lateral branch a
portion of the apical cell-cavity, which, under ordinary cir-
cumstances, becomes the primary cell of a leaf, is applied to
the formation of the rudimentary cell of the branch. It is
probable that the formation of the branch takes place earlier
than that of the leaf which stands at the same elevation in
the ascending line of the spiral of the phyllotaxis. Assuming
this to be so, the process can hardly be viewed otherwise
than as a separation from the four-sided terminal cell, of an
irregularly shaped cell of the second degree with a three-
sided apical surface ; after which separation the apical cell
divides by a septum which is parallel to one of the shorter
sides of the apical surface, and is inserted in the angle
formed by the oldest lateral wall of the apical cell with one
of the lateral surfaces of the rudimentary cell of the branch.
This latter division would restore the apical cell to its three-
sided pyramidal form. The direct observation of this pro-
cess can only be accidental. Indications, however, of such
a state of circumstances clearly exist in the occasional
occurrence of very slender apices (of stems), whose conical
end extends far above the last leaf-rudiment which is visible
in profile, so that in the optical section of the naked cone
two superposed cells of the second degree can be distin-
guished on one or on both sides. f

Most lateral branches ramify soon after their formation.
Schimper (1. c, p. 30), judging from the anatomical struc-
ture of the points of origin of perfect branches, concludes

* In the ' Vergleichende Untersuchungen,' p. 62, 1 made use of an expression
which might lead to the belief that I considered the lateral branches as axile in
their origin. This arose from my having only had in view the relation of the
elementary cell of the lateral branch to the leaf below it. Schimper, at p. SO
of his work on Sphagnum, has rightly objected that, the position of the rudi-
mentary as well as of the perfect lateral branches is always at the side, near
the margin of the leaf which stands at the same elevation. 1 consider Schimper,
however, to be in error (1. c, p. 30) in supposing that certain oval (occasionally
stalked) cells, which are interpolated between each two moderately distant
leaves, and which are seated upon the outer surface of the stem, are to be
looked upon as the rudimentary cells of lateral branches. These cells are
nothing more than the young state of the bicellular hairs, with oval terminal
cells, which occur not unfrequently upon the stem of Sphagnum, and which
are figured by Schimper himself (pi. v, f. 2).

f Such terminal buds have often been figured, for instance, by myself in the
'Vergl. Unters.' (pi. xiii, f. 1), and by Schimper (1. c., pi. iii, f. 2, 7).

THE HIGHER CRYPTOGAMIA. 139

that the branch clevelopes a number of lateral branches
before the commencement of the formation of leaves ; and
he treats the scale-like appendages of the young branch-
buds, which I considered to be leaves, as being the rudi-
ments of lateral branches (PL XVII, fig. 6). Continued
observations have not afforded me a single phenomenon
confirmatory of this opinion of Schimper's. I have found,
without exception, that the lateral branches develope indis-
putable leaves at a very early period, almost close to their
place of insertion into the principal stem (PL XVII, fig. 1),
and I have never seen a branch of the second order inserted
on a primary branch underneath the place of origin of the
first leaf. The points at which the axile cellular strings
are separated from the branches., often appear to be enclosed
within the bark of the fully developed principal shoot (1. c,
pi. iv, fig. 4) ; but this appearance is caused by the com-
paratively late commencement of the growth of this bark in
the direction of its thickness. ; the bark is closely attached
to, and grows round, the base of the branches, and strips
off their lowest leaves.

I found that the development of the stem and branches
of Orthotrichum affine agrees in all essential particulars with
that of Sphagnum.

The first division of the rudimentary leaf-cell, which pro-
trudes slightly above the circumference of the terminal bud,
takes place by means of a septum springing laterally from
its longitudinal axis, and perpendicular to the surfaces of
the leaf. This division is succeeded by that of the apical
cell, which takes place by means of a septum inclined in
the opposite direction, meeting the one previously formed
at an angle of 90° (PL XVII, fig. 3). By the repeated
division of the apical cell by means of alternately inclined
septa, the leaf grows in length. During this time the form
of the apical cell is that of a low, three-sided prism, and the
form of the cells of the second degree is that of a procum-
bent parallelopiped.

Contemporaneously with or very shortly after the forma-
tion of a new cell of the second degree, the next older one
divides by a transverse septum, which, like all those which
take part in the formation of the leaf of Sphagnum, is per-

140 HOFMEISTER, ON

penclicular to the surface of the leaf. The edge formed by
the contact of this latter septum with the upper side wall
of the mother-cell coincides exactly with the line in which
the membrane just produced in the apical cell cuts the
boundary wall of the cells of the first and second degree.
The septum in question forms a right angle with the side
walls of the cell of the second degree ; its direction is,
therefore, exactly the same as that of the septum by which
the apical cell was con temporau eously divided. The inner
of the cells into which the second youngest cell of the
second degree is divided has a rather long, rectangular,
basal surface. Both the cells of the third degree, which are
produced by the division of the cells of the second degree,
are soon divided, by longitudinal septa parallel to the side
walls, into equal parts, whose basal surfaces are almost
exactly square (PI. XVIII, fig. 1). A similar process takes
place upon each further division of the apical cell of the
leaf. All the cells of the edge of the leaf which lie in the
course of the prolongation of the line of direction of the
newly produced septum of the apical cell divide, almost
contemporaneously, with the apical cell, by septa whose
direction coincides with that of the above-mentioned line
(PI. XVIII, fig. 1*). The result of these processes is that
in all species of Sphagnum the young leaf, with the excep-
tion of its margins, appears divided into regular squares.
With the exception of its edge, which appears composed of
somewhat elongated cells, the entire surface of the leaf con-
sists of cells whose basal outline is square, and each four
of which are in contact at their edges. It is only occa-
sionally that in these divisions one cell is passed over, and
then one cell of the interior of the leaf is twice as wide as
its neighbours, and its basal surface has the form of a paral-
lelogram (PI. XVIII, fig. 1 ; see one of the cells of the fifth
of the oblique rows to the left).*

It is self-evident that, by the repeated division of the
cells, the lower, older portion of the leaf increases consider-

* From the above-mentioned processes by which the chess-board-like
arrangement of the cells of the young leaf is produced, Niigeli concludes that
the division of one cell has a manifest effect upon the neighbouring cell, and
causes the division of the latter in the same direction ('Pfianzen-phys. Unters.,'
i, p. 7S). On the other hand, I find in these facts a new ground for the con-

THE HIGHER CRYPTOGAMIA. 141

ably in width. Reckoning from the youngest leaf backwards,
the sixth leaf of a shoot embraces one half of the stem ; the
twelfth embraces from five eighths to six eighths. Inasmuch
as, during the multiplication of the cells of the base of the
leaf, the cells of the stem upon which they are seated are
in an active state of multiplication in a tangential direction,
it follows that the place of attachment of the leaf to the
stem continues, relatively, of a considerable width, amount-
ing to one third of the circumference of the stem. Every
section made through that part of a principal shoot which
lies nearly under the apex meets, not only the longitudinal
line of each eighth leaf, but also lateral portions of five
intermediate leaves ; so that, in most cases, the points of
insertion of two leaves are only separated by one cell of the
cortical layer.

When the division of the apical cell of the leaf (which
division takes place by means of septa diverging alternately
from the median line) ceases, a multiplication of all its cells,
excepting those of the margin, commences ; this multipli-
cation begins at the tip, and progresses rapidly from thence
to the base. Each of the square cells divides into two
rather unequal parts by means of a septum parallel to one
of the sides, but not exactly traversing the middle point of
the cell (PI. XVIII, fig. 2, below, to the left). The larger
of the two is then divided, by means of a septum parallel
to the narrow sides, into two cells of unequal size, the
larger being square and the other somewhat elongated
(PI. XVIII, fig. 2). After the termination of these divi-
sions the surface of the leaf consists of a system of
square cells, each of which is surrounded by four oblong
cells.

In the oblong cells chlorophyll-granules are produced,
which increase rapidly and considerably in number and in
size (PI. XVIII, figs. 3, 9). On the other hand, the pale-
green, highly refractive, and finely granular mucilage, which

elusion which I had previously drawn from similar appearances ('Abhandl. Kon.
Sachs. Ges. d. Wissensch.,' vol. iv, p. 161), viz., that the growing power which
regulates the form of compound vegetable organs is mainly proportionate to
the form and number of the new cells in process of production, and that such
power does not exhibit itself in each peculiarity of the process of cell-multipli-
cation.

142 HOFMEISTER, ON

fills the larger square cells, disappears, after having become
turbid and gramous, but without dividing into bodies of
any definite form. The contents of these latter cells
become clear like water. A considerable expansion of the
leaf-cells now ensues, especially in the longitudinal direc-
tion. It begins at the apex of the leaf, and proceeds from
thence rapidly downwards. The cells of the margin, which
divided once, and only partially, by means of septa at right
angles to the edge of the leaf, cannot keep pace with the
increase in size of the numerous median cells ; the leaf
assumes more and more the form of a cap. At the same
time the first traces of the well-known annular and spiral
threads begin to be visible upon the inner walls of the
larger square cells. A longitudinal division of many (often
of all) of the cells with watery contents frequently precedes
the appearance of the threads,. especially in Sphagnum squar-
rosum, so that each two thread-cells lie near one another
(PI. XXIII, fig. 4). Not unfrequently, also, many of the
small chlorophyll-bearing-cells divide by transverse septa
(PL XXVIII, fig. 3). In the mean time the chlorophyll-
granules in the small cells, which form a complicated net-
work between the thread- cells, increase considerably in
size.

In the greater number of mosses, e.g. Phascum, Bryum,
Hypnum, Polytrichum, whose early development has been
admirably figured by Nageli, the formation of the leaves
agrees in the principal feature — that is to say, in the
nature of the repeated division of the one apical cell — with
Sphagnum. An essential difference exists, however, in the
fact that the number of the cells in the leaves of these
mosses increases considerably by the repeated bisection of
the cells of the lower part of the leaf, even after the division
of the apical cell has ceased, after the latter cell and its
neighbours have expanded considerably, after the contents
have become transparent, and the walls of the cells of the
apex of the leaf have become considerably thickened. In
Sphagnum this supplementary multiplication of the cells of
the base of the leaf can never be distinguished. Upon the
last division of the apical cell the lateral margin of the leaf
consists of a number of cells (normally from eighteen to

THE HIGHER CRYPTOGAMIA. 143

twenty in Sphagnum acutifolium), which is afterwards only
doubled by transverse division of the marginal cells. The
above-mentioned phenomenon, on the other hand, is very
distinctly marked in Polytrichum and Fissidens. It is well
known that the leaves of the latter genus are arranged in
two rows. The terminal bud is surrounded by the peculiar
pocket-shaped duplication of the base of the last-formed
leaf; each older leaf of the bud also encloses the younger
leaves and the summit of the shoot in the already perfected
duplication of its base. The very young leaves resemble
the first rudiments of the leaves of Sphagnum. But when
the leaf is only five cells in height, the method of cell-
multiplication changes. As in Sphagnum, the cell of the
second degree divides by a septum at right angles to the
side walls. The septum which thereupon divides the outer
of the newly formed cells into two, stands at right angles
to the above septum, like the similar septum in Sphagnum ;
on the other hand, the membrane which originates in the
inner cell is at right angles to the median line of the young
leaf (PI. XVIII, fig. 17, a). The two cells of the fourth
degree belonging to the marginal cells of the leaf divide,
at first, by a septum parallel to the margin of the leaf. The
next septum, however, in both cells is at right angles to
the margin of the leaf. The transverse division corre-
sponding to this division is suppressed in the cells of the
two rows adjoining the longitudinal axis of the leaf, in con-
sequence of which these cells are double the length of the
neighbouring cells (PI. XVIII, fig. 17). The leaf continues
to widen by the further division of the cells of its margin,
caused by septa parallel to the edge. Sometimes indi-
vidual marginal cells are divided also by longitudinal
septa.

The formation of the pocket at the base of the leaf com-
mences when the base of the leaf has attained a width of
eight cells. At this time from five to eight of the lowest
cells of that margin of the surface of the leaf which is turned
towards the terminal bud become arched upwards to a con-
siderable extent ; the protruded portions are then separated
from the primary cell-cavities by means of septa parallel to
the surface of the leaf. By this means a raised line origi-

144 H0FME1STER, ON

nates, which is attached laterally to the margin of the leaf,
and consists of a longitudinal row of cells. These expand
downwards from the longitudinal axis of the leaf, and exactly
keep pace with the further multiplication of the cells from
which they sprang. As the increase in width of the leaf is
much less at the base than close above it, it follows that
in the perfect leaf the commissure of the two parallel cel-
lular surfaces appears to be considerably inclined sideways,
running obliquely from the margin of the leaf to the base
of the mid-rib. By the peculiar development of the bases
of the leaves, nature has more than sufficiently compensated
the youngest portions of Eissidens for the deficient protec-
tion which, owing to their mode of arrangement, the leaves
would be able to afford.

^ When the young leaf of Eissidens has attained a length
of J-'", the multiplication of the apical cell terminates. At
this time the leaf retains the form which it had when in
a younger state; it is less slender than Avhen more fully
grown. The further multiplication of its cells is produced
exclusively by the continual division of those of its lower
portion. The great activity of this multiplication is shown
from the simple statement that the number of the cells of
the proportionally small point of attachment of the leaf,
when reckoned transversely, amounts to thirty.

The six longitudinal rows of cells adjoining the median
line of the leaf of Eissidens become transformed into the
mid-rib, by division produced by septa parallel to the sur-
face of the leaf, and by the division of the newly formed
cells by septa perpendicular to the surface of the leaf. The
base of the mid-rib in the perfect leaf is immediately adja-
cent to the duplication of the lower part of the margin of
the leaf.

The examination of half-developed leaves of mosses which
are undergoing this process of cell-multiplication will afford
one of the most convenient methods for the accurate inves-
tigation of the process of cell-division and the formation of
chlorophyll. The object is not large enough for the micro-
scopes of the present day. I believe, however, that I have
already made out some interesting peculiarities in Eissi-
dens. In the cells close to the base of the leaf the nucleus,

THE HIGHER CRYPTO GAMI A. 145

which has the appearance of a bright circle, is surrounded
by an apparently homogeneous, pale greenish mucilage.
The intensity of the green colour increases towards the
apex. In cells which are about to divide, the formation of
two nuclei, in the place of the primary one which has dis-
appeared, precedes the formation of the transverse septum,
as is the case generally in the higher plants ; but, besides
this, the green mucilage divides into two globular masses,
each of which surrounds one of the newly formed nuclei
(PI. XVIII, fig. 18). Higher up, in cells whose multipli-
cation has ended, the nucleus is no longer seen, but two
large chlorophyll-bodies are found in the cell-cavity, in the
interior of which bodies some starch-grains occur (PL XVIII,
fig. 19). In the cells close to the apex of the leaf, whose
walls have already become thick, the number of chlorophyll-
bodies amounts to four, six, eight, or even more. The
appearances which are seen during the formation of the
chlorophyll-bodies in the leaves of Sphagnum and of Phas-
cum cuspidatum are essentially the same as those observed
in Fissidens. In leaves of Sphagnum where the division
of the cells into three parts has extended as far as the base,
and at whose apex the last active process (viz., the differen-
tiation of the cells into those with, and those without, chlo-
rophyll) has occurred, the cells of the base of the leaf are
found to be quite filled with finely granular, yellowish green
protoplasm, within which the nucleus appears in the form
of a bright circle. Somewhat nearer to the apex of the leaf
this protoplasm exhibits numbers of immeasurably small,
dark-green particles, not individually distinguishable, by
which the protoplasm is rendered turbid.

Hitherto all the cells of the leaf develope themselves
equally. Towards the apex, however, the coloured matter
within the quadrate cells diminishes more and more until
it disappears altogether, whilst in the oblong cells it appears
suddenly conglomerated into one or two spheroidal masses
or chlorophyll-bodies. Nearer still to the apex of the leaf
the chlorophyll-bodies in the oblong cells increase in number
and diminish in size ; this is manifestly caused, by the divi-
sion of the existing bodies, inasmuch as some of them may

10

146 HOFMEISTER, ON

occasionally be seen in the actual process of constriction
(PL XVIII, fig. 4).

The perfect chlorophyll-bodies are small ellipsoids, some-
what flattened in the direction of the shorter axis, and
having the snbstance of their periphery somewhat denser
and more strongly coloured than that of their interior, so
that they present a vesicular appearance. They usually
contain one or more very small starch- granules.

In young leaves of Phascum cu-qnclatum, also, the less deve-
loped cells exhibit only one or two large chlorophyll-bodies ;
in more fully developed cells they become continually more
numerous and smaller. The perfect bodies have a vesicular
appearance, and usually contain several starch- granules ;
when the cell which surrounds them is ruptured, so that water
is brought in contact with them, their entire mass swells up
largely, running together ultimately into a shapeless jelly.

The previously described process of the formation of the
large chlorophyll-bodies of Anthoceros is similar to that
here mentioned. From these facts I drew the conclusion*
that in young cells the chlorophyll is colourless, inasmuch
as the colouring matter is dispersed throughout the muci-
laginous cell-contents in the form of immeasurably small
particles. As the development of the cell proceeds, the
coloured portions unite to form globular drops, which are
capable of multiplying themselves by division. This opi-
nion was opposed to that of Nageli (' Zeitschr. f. wissensch.
Bot.,' H. 3 & 4, Zurich, 1846, 111), who assumes that the
chlorophyll-bodies originate in the form of small, coloured
granules, which gradually increase in size : it was, however,
in accordance with Nageli's view to the extent of assuming
a vesicular structure in the chlorophyll-bodies, and it con-
firmed the fact, first pointed out by Nageli, of the division
of the latter bodies. The idea of a vesicular structure in
the chlorophyll-bodies was opposed by H. v. Mohl, who
relied upon certain appearances exhibited by those bodies
when distended with water (< Bot. Zeit./ 1855, 107, 109) ;
but v. Mohl also, having eventually modified an earlier opi-
nion, came to the conclusion that, however chlorophyll may

* ' Vergleicliende Uiitersuchuugen/ Lpz., 1851, p. 10.

THE HIGHER CRYPTOGAMIA. 147

be formed, nothing more seems necessary for its production
than that green colouring matter should be formed in a
cell, and should enter into combination Avith a mass of pro-
teine substance. The investigations of Arthur Gris (' Ann.
des Sc. Nat.,' iv ser., t. vii, p. 79), and of Sachs (' Sitzungs-
berichte Wiener Akademie,' xxxvii, (1859,) p. 108), have
since shown that even in higher plants the chlorophyll-
granules are formed by the disruption of a sharply-defined
mass of protoplasm, often of no determinate shape, the
green colour of which in certain cases becomes apparent
before the disruption, in others during that process, and in
others again after the disruption, and which mass of proto-
plasm is usually agglomerated round the nucleus.

The development of the leaves of mosses has lately been
a matter of discussion. Nageli asserted that the leaf
grows exclusively at the apex and the edge. (c Zeitschr.
fur wiss., Bot.' ii, 175). Schleiden, on the other hand
(Grundziige, 3 Aufl), advanced a diametrically opposite
opinion. According to him the leaf is pushed forwards by
the multiplication of cells lying inside the circumference
of the stem ; the apex of the leaf being the oldest, and
its base the youngest portion. With regard to the moss
which Schleiden examined, viz., Sphagnum, this is abso-
lutely incorrect ; with regard to the leaves of liverworts
and phcenogams it is only true in part, and to a very
limited extent. Both observers have generalised too ex-
tensively from the results they have obtained in their
investigations of mosses, although INageli subsequently
limited his too vague conclusions, by acknowledging the
frequent occurrence of intercalary cell-multiplication,* a
very manifest fact long previously pointed out by Grisebach
(' Wiegm. Arch.' 1846, p. 1). I have before attempted
to show that, with regard to mosses, the truth lies
between the two opinions. The first rudiment of the leaf
is formed from an outwardly-protruding cell of the circum-
ference of the terminal bud, by means of continually
repeated division of the apical portion. In this rudiment

* Nageli called this " accidental cell-formation ," an expression (lie incorrect-
ness of which he subsequently acknowledged, 'Prlanzen physiol. Unters.,'
i, p. S3.

148 HOFMEISTER, ON

of the leaf, which in Polytrichum, for instance, attains a
length of twenty-four cells, the apex is the youngest, the
base the oldest portion. In most cases the cells of the
base of the leaf-rudiment multiply actively, by which
means the leaf acquires its ultimate number of cells. Then
the cells of the base of the leaf are relatively younger than
those of the apex.

The naked ends of those branches which are destined
to bear fruit change the conical form of the vege-
tative bud into a flattened hemispherical one. Many
of the cells of its upper surface grow out into short
papilla) (PI. XIX, fig. 1). Each of them divides by a
septum inclined to the horizon ; the upper one of the
newly formed cells divides by a septum perpendicular to
that already formed and inclined in an opposite direction.
In the terminal cell of the cellular body, which makes
its appearance above the surface of the bud, the divi-
sion is continually repeated by septa inclined in dif-
ferent directions (PI. XIX, fig. 1 ; PL XX, fig. 1). The
cells of the second degree, except some of the lower,
oldest (from two to six in number) cells, divide soon after
their formation by radial vertical septa. Thus, in a short
time, there is formed in the space surrounded by the
youngest leaves, a number of short, cylindrical, cellular
bodies, composed of four vertical rows of cells, intermixed,
in many of the mosses, with long multi-cellular hairs,
which have originated in the division by transverse septa of
certain of the papillate superficial cells of the bud. These
clavato- cylindrical masses of cells are the first rudiments of
the archegonia as well as of the antheridia.

When the young archegonium has attained a height of
from six to eight cells, all the cells belonging to one of the
four perpendicular rows of cells of which (irrespective
of the base and the growing apex) it consists, divide
by septa parallel to the chord of the arc of the free, arched,
outer wall, and cutting the side walls of the cell at an angle
of about 45°, by which means the mother-cell is divided into
an outer four-sided, and an inner three-sided cell. Each
one of the newly-formed cells of the third degree (which
form the continuation upwards of the string of diagonally-

THE HIGHER CRYPTOGAMIA. 149

divided cells) divides in the same manner immediately
after its formation, such division being, in most instances
exactly contemporaneous with the next division of the
apical cell, very seldom somewhat later, often earlier (PL
XX, figs. 2, 3).

The archegonium now consists of a central string of
cells, which is surrounded by from four to six longitudinal
rows of cells. There are far more frequently six rows, in
consequence of the division of two of the original four, by
radial longitudinal septa (PI. XX, fig. 7). The arche-
gonium resembles, therefore, in its development, as well
as in its structure, the like organ in the liverworts. One
of the cells of the central string swells to a remarkable
extent, especially in width, whilst the upper end of the
archegonium continues to grow. This cell, however, is
never so near to the base of the archegonium, as in the
liverworts ; amongst the mosses which I have examined
it lies lowest in Phascum and Archidium, where it is the
third, fourth, or fifth, reckoned from below (PL XX, fig.
2 ; PL XXIII, fig. 13). Soon after it begins to swell the
cells underneath it divide by transverse, and partly by
longitudinal septa, whereby they expand only in length,
not in breadth. This cell-multiplication is more active
close under the swollen cell, than at the base of the arche-
gonium. In Phascum those cells which surround the sides
of the swollen cell divide, in the first instance, only by
transverse septa and by longitudinal septa perpendicular
to the outer surfaces (PI. XX, fig. 4) ; the division of the
above cells, by longitudinal septa, parallel to the axis of
the organ, commences at a somewhat later period (PL XX,
fig. 5). In other genera, as for instance, Funaria, Fissi-
dens, Dicranum, and Polytrichum, the cells which cover
the central cell of the ventral portion of the archegonium,
are already divided by longitudinal septa parallel to the
outer surface, long before the bursting of the apex of the
archegonium ; and this occurs particularly early in Sphag-
num (PL XV 111, fig. 14), where, even before the opening
of the top of the archegonium, this division is repeated in
the inner as well as in the outer cells (PL XVIII, fig. 15).
In this genus, consequently, the ventral portion of the
archegonium is larger than in any other moss.

150 HOFME1STER, ON

By these processes the lower portion of the archegonium
becomes a pear-shaped cellular mass, which, at the point
where it passes into the upper cylindrical portion (the neck)
of the archegonium, surrounds the enlarged cell of the cen-
tral string. In most instances the cell of the central string
lying immediately above the enlarged cell, exhibits a con-
siderable increase of its dimensions (PI. XIX, fig. 5 ; PL
XX, fig. 4) ; this is especially remarkable in Sphagnum
(PL XVIII, fig. 15).

Like all the cells of mosses the enlarged cell in question
exhibits, from its first appearance, a manifest nucleus. In
the very young archegonium the nucleus lies free in the mid-
dle of the cell, surrounded on all sides by protoplasm of
uniform density (PL XVIII, fig. 14 ; PL XX, figs. 2, 4) ; at a
later period, after the separation of the contents of the cell
into two parts, — viz., the thick coating of the wall, and the
less dense fluid contents of the median cavity, — the nucleus
lies close to the side wall of the cell, surrounded by a thick
accumidation of granular protoplasm, which sends forth
radiate prolongations over the inner surface of the cell
(PL XIX, figs. 5, 6). At this time there is seen under-
neath the primary nucleus of the cell, which is still very
distinct, a small daughter-cell, occupying about an eighth
part of the cell cavity, and having highly refractive con-
tents, and a bright nucleus without nucleoli (PL XIX,
figs. 5, 6). Contemporaneously with the appearance of
this cell, the transverse septa, by which the separate cells
of the axile longitudinal string of cells forming the neck
of the archegonium are divided from one another, begin
to dissolve. Even before these transverse septa have
altogether disappeared, even before the dissolution of the
transverse septa of the lowest of the cells of the axile
string, and therefore before the formation of the canal
which traverses the neck of the archegonium longitudinally,
the central cell is found to be almost filled by a free
spherical cell, which is either suspended freely, or touches
the wall of the mother-cell on one side, and which contains
a globular central nucleus (PL XVIII, fig. 15; PL XIX,
figs. 7, 8, 20; PL XX, figs. 5, 6, 8). The primary
nucleus of the cell is no longer present. These circum-
stances must lead to the conclusion, that the germinal

THE HIGHER CRYPTOGAMIA. 151

vesicle (i. c, the small free daughter-cell of the central cell
of the archegonium), grows with extraordinary rapidity,
and displaces the dissolving primary nucleus of the central
cell. In F/inaria hyyrovietrica the ripe germinal vesicle is
usually in close proximity to the transverse septum, which,
even after the canal of the neck is fully formed, and some-
times even after the apex has opened, still shuts on the
central cell of the archegonium (PI. XIX, fig. 8). It often
happens, however, in Funaria, in Phascum, and in Liver-
worts, that the germinal vesicle rests upon the bottom of
the central cell (PI. XIX, fig. 7 ; PL XX, fig. 9), or that
it lies against one of the side-walls of the latter (PI. XX,
figs. 5, 6, 8).*

After the termination of the longitudinal growth, the
cells of the apex of the archegonium divide by radial septa
which are partly vertical and partly inclined sideways ; and
to some extent also by transverse septa. In many genera,
such as Polytrichum and Sphagnum (PI. XVIII, fig. 15), the
new cells thus formed expand in a radiate manner, in con-
sequence of which the apex of the archegonium appears
strongly clavate. In the mean time, the walls of the string
of cells which traverses the neck of the archegonium dis-
solve. The dissolution progresses from above downwards.
Thus there originates in the axis of the neck a canal, con-
taining only mucilaginous fluid, which leads to the large
cell in the upper end of the ventral portion. Suddenly the
cells of the apex separate from one another, and bend them-
selves backwards in the form of irregular flaps ; in this state
they form the so-called stigma (PL XX, figs. 6, 9, 13).
The archegonium is now in the condition in which I con-
sider it to be ready for impregnation. After the rupture of
the apex of the archegonium, the mucilage which fills the
canal of its neck not unfrequently oozes out of the opening,
protruding above the funnel-shaped mouth in a hemisphe-

* The rapid disappearance of the primary nucleus of the central cell, and the
agreement with it in size and form of the nucleus of the germinal vesicle, led
me at first to the conclusion (' Vergl. Unters.,' p. 67) that the germinal vesicle
might originate by free cell-formation round the primary nucleus of the central
cell. The mode of its development, as given above, was first arrived at by me
in 1S54 ('Berichte Kon. Sachs. Ges. d. Wissensch. Math. Phys. CI.,' 1854,
p. 95).

152 HOFMEISTER, ON

rical form. Afterwards it is often agglomerated into glo-
bular masses, — some small and some large, — of transparent
hyaline matter, as is the case in the Jungermanniae.
These processes may be seen especially clearly in Archidiam
phascoides (PL XXIII, figs. 1—3).

The product of the dissolution of the transverse septa of
the string of cells which traverses the longitudinal axis of
the neck of the archegonium frequently consists, in mosses,
of a vermiform mass of highly refractive, hyaline, transpa-
rent mucilage (PI. XIX, fig. 8). It seems that the forma-
tion of this string of mucilage is favoured by dryness of
habitat. I seldom failed to find it in plants of Funaria
kyr/rometrica which had grown in dry places. It is much
less often found in plants taken from moist situations.
In Phascum ctisjnclafum, a part of the contents of the wide
axile string of cells lying immediately over the central cell
of the archegonium very often assumes the form of an irre-
gularly-shaped heap of coarse granules (PL XX, figs. 5, 8).

The first stages of development of the antheridia of
mosses entirely correspond, as has been already stated,
with those of the archegonia. A clavate mass of cellular
tissue protrudes in a precisely similar manner above the
upper surface of the end of the stein, consisting, — with the
exception of the continually multiplying terminal cell and
the cells of the base, — of four vertical rows of cells : in an
almost precisely similar manner, a string of cells traversing
the axis of the organ is formed by the division of the cells
of one of the above rows; this occurs in the species of
Phascum, Gymnostomum, Bryum, Eucalypta, and Funaria
(PL XIX, figs. 1, 2, 3). In other cases diagonal septa ori-
ginate in each of the four rows of cells, after which radial
septa are formed in the outer ones of the new cells ; by this
means the antheridium becomes much more massive. This
is the case in Polytrichum.

The inner cells of the young antheridium multiply very
actively in all three directions (PL XIX, fig. 4). The cells
of the upper surface divide only by septa perpendicular to
the outer walls, and much less frequently than the inner
cells. The antheridium thus becomes a clavate sac, con-
sisting of a single layer of cells, which encloses an elongated

THE HIGHER CRYPTOGAMIA. 153

ellipsoid group of very small cellules adhering firmly to one
another. In each of the latter, a spiral thread, consisting
of nitrogenous matter which is coloured brown by iodine,
is produced inside a lenticular vesicle which lies free in the
interior (PL XX, fig. 16).

The tabular cells of the walls of the antheridium contain
chlorophyll, and in the young state a flat lenticular nucleus
also, whose major axis is parallel to the outer surface of the
cell (PI. XIX, fig. 4). When the antheridium approaches
maturity, the colour of the chlorophyll-granules in many
mosses becomes a yellowish-red. This is the case in Funaria
hygrometrica, Brgum ctsspiticium, Polytrichum juniperinum,
Gymnostomum pyriforme, and Nechera complanata. The
antheridia are usually intermixed with jointed hairs, the
so-called paraphyses, whose terminal cells are often (as is
the case in Mnium hornum and Funaria hygrometrica)
swollen to a clavate form, and in Polytrichum produce a
lancet-shaped expansion at the apex, originating from con-
tinual cell-division by means of differently inclined septa.
The fully-ripe antheridium opens at the apex, and permits
the escape of the small, enclosed cells, which contain the
spermatozoa. The process is very easily seen in water on
the stage of the microscope ; and that the same thing takes
place in nature, appears from the fact, that in every rich
male inflorescence in mosses, empty antheridia, open at
the apex, are found in company with ripening and ripe
antheridia.

The bursting of the apex of the ripe antheridium of
Funaria hygrometrica occurs thus : — the apical cell, and
the youngest cell of the second degree, which is separated
from the latter by a steep septum, exhibit a considerable
enlargement of their outer wall, which expands in a
vesicular manner ; but the red colouring corpuscles of the
cell contents, (whose interior is now usually occupied by a
starch granule) do not enter into the expanded space.
Careful investigation shows that the cuticle only of the
cells of the apex of the antheridium is forced outwards,*
and that the cavity between it and the firm membrane

* See Unger's figure of an antheridium of Polytrichum in the act of bursting
<N. A. A. C. L.,' v. xviii, p. II (1837), p. 790. PL 57, f. 1.

154 HOFMEISTER, ON

which immediately encloses the contents of the epidermal
cells, is filled with a transparent, almost fluid, jelly, which
can be nothing else than a product of the swelling up of
the median layer of the walls of those cells which occupy
the apex of the antheridium. Suddenly the cuticle of both
the above-mentioned cells splits transversely ; the contents
of the antheridium are driven out between the detached
cells of the epidermal layer in the form of a mucilaginous
mass, shaped like intestines ; these contents escape at first
with great rapidity, and afterwards with a slower motion,
which sometimes, by fits and starts, exhibits a momentary
acceleration. The walls of the cellules in which the len-
ticular vesicles, which produce the spermatoza, are gener-
ated, are now swollen to a mucilaginous jelly. The latter
is rapidly dissolved in water on the stage of the microscope,
the vesicles are dispersed in the fluid, and are soon rup-
tured by the spermatozoa in their efforts to escape. The
latter move about for some little time in the water, but
with no very great rapidity. I have observed the motion
to last for four hours in Poli/trichiimformosum. The mode
of bursting of the antheridium leads to the conclusion that
a radial expansion, and swelling up of the walls of the
epidermal cells, especially of those of the apex, are at least
as effective in producing the rupture, as is the outward
pressure produced by the swelling of the contents.

The development of the antheridia of Sphagnum, which
are situated singly in the axils of short lateral shoots, differs
in some points of secondary importance from that which
occurs in Phascum, Bryum, Funaria, &c. There is a long-
row of cells of the second degree in which division does not
take place ; a thin cylindrical double row of cells is pro-
duced, the end of which swells in a clavate manner. A
few only (two or three) of the cells belonging to the double
pairs of cells of the third degree which lie nearest to
the apex of the organ, divide, by means of a septum
parallel to the outer surface, into inner and outer cells
(PI. XVIII, fig. 11). The former become the mother-
cells of the vesicles which produce the spermatozoa ; they
divide actively in all three directions until at last they form
a spherical or oval group of closely-packed, small, tessellated

THE HIGHER CRYPTOGAMIA. 155

cells (PI. XVIII, fig. 12), in each of which a spirally
folded spermatozoon is produced in the interior of a len-
ticular vesicle. The cells which surround these central
cells multiply by division, which takes place by means of
septa perpendicular to the outer surface, and become the
covering layer of the antheridium. On their outer side
there is formed a glassy, transparent, very tough cuticle,
which may be easily detached. When the organ is ripe
the cuticle bursts at the apex ; the vesicles enclosing the
spermatozoa, having become free by the dissolution of the
walls of their mother- cells escape at the opening, disperse
themselves when under water in the surrounding fluid, and
set the spermatozoa free, which then commence their
revolving motion. Their spiral has from two and a half
to three turns, and is sometimes a right-handed, some-
times a left-handed one. The anterior end of the sper-
matozoon carries two thin motile cilia attached laterally
(PL XVIII, fig. 13). The covering cells* of the antheridia
usually become isolated after maturity, like those of Antho-
ceros, Fossombronia, &c. ; the cuticle holds together for a
considerable time.

Schleiden was of opinion that the antheridium of Sphag-
num was a large sac-like cell, in whose fluid contents the
vesicles which produce the spermatozoa swam about freely.
This notion is quite erroneous. Until just before matu-
rity, the walls of the small, tessellated, closely-packed cells
remain quite intact, each of them enclosing one of the
vesicles. The nature of their arrangement is such, that the
directions of the primary divisions of the seven-surfaced
central cell of the very young antheridium may be easily
recognised.

Fruit is developed only in those mosses where the arche-
gonia are in the neighbourhood of antheridia. Any Botanist
paying attention to the growth of mosses will be able to
produce instances, in addition to those afforded by the older
observers, to prove that female dioecious mosses, in whose
neighbourhood no male plants of the same species occur,
produce perfect archegonia, but never fruit. At Leipzig, in

* The chlorophyll granules of these cells do not change colour when the
antheridium is ripe.

156 HOFMEISTER, ON

certain localities, female plants only of Mnium undulatum,
Mniitm punctatum, and Bryum ccsspiticium occur. In such
places I have found every year numerous vigorous arche-
gonia, but never a single fruit. When fruit is found in
these species, male plants are invariably to be met with in
the immediate neighbourhood.

I have not yet succeeded in finding spermotozoa in the
central cell of the archegonia of Mosses near the germinal
vesicle, as I have done in Ferns.* I have, however, seen
in Funaria a moving spermatozoon which had penetrated
through a third part of the length of the neck of an arche-
gonium, which was ready for impregnation.

The first symptoms of the commencement of the deve-
lopment of a fruit, are a considerable enlargement of the
germinal vesicle of the elongated ellipsoidal cell which fills
the large cell in the upper end of the ventral portion of the
archegonimn (PI. XIX, fig. 17 ; PI. XX, fig. 10), and the
appearance in it of a horizontal or slightly-inclined trans-
verse septum (PI. XIX, fig. 21 ; PI. XX, fig. 10). In Brijum
argenteum the upper part of the two cells divides again,
once or twice, by means of septa parallel to that first formed
(PI. XIX, fig. 22"' b). A septum inclined at a considerable
angle, and seated upon the uppermost of these horizontal
septa, is then produced. In Phascum, Funaria, and Fissi-
dens, this inclined septum is formed immediately after the
production of the first horizontal one (PL XX, figs. 11, 12).
The upper terminal cell of the young fruit -rudiment is then
divided by a septum inclined in a contrary direction to the
one last formed, then by another parallel to the last but
one, and so on. The longitudinal growth of the fruit-
rudiment is carried on by division of the terminal cell by
means of differently inclined septa (PL XIX, figs. 9 — 11,
22; PL XX, figs. 11—15).

The young rudiment of the fruit, when consisting of from
one to four cells, may be easily detached (PL XX, figs. 11*,
\'2b'c). It occupies only a very small space of the upper
half of the ventral portion of the archegonium, in the cavity
of which it lies free (PL XX, figs. 11, 13). During its

* 'Ber.der K. Sachs. Ges. d. Wiss.,' 1S54, p. 54.

THE HIGHER CRYPTOGAMIA. 157

further longitudinal growth, it presses together the neigh-
bouring cells of the ventral portion, which have multiplied
considerably during the development of the fruit-rudiment.
This is very remarkable in Punaria (PI. XIX, fig. 11). At
the same time, the fruit-rudiment penetrates by its lower
conical end continually deeper into the tissue of the arche-
gonium.

The cells of the second degree which are formed by the
continually-repeated division of the apical cell, and whose
form is that of a flat semi-cylinder, divide by a radial
vertical septum. This division usually takes place before
the next division of the apical cell. ' The cells thus formed,
each of which has a three-sided basal surface, divide by a
septum parallel to the chord of the arc of the free outer sur-
face, into an inner eel] with a three-sided, and an outer one
with a four-sided, basal surface (PI. XIX, figs. 9, 10, 11, 11*,
22,22^Pl.XX,figs.l4,15;Pl.XXI,fig.2"^c;Pl.XXIII).
The undermost margin of each such septum extends a little
beyond the line of contact of the corresponding septum of
the next lower cell. The next cell-division is that of the
outer cells by a radial longitudinal septum. Then all the
outer and inner cells of the group formed by the division of a
cell of the second degree divide by horizontal septa, the
inner ones often sooner than the outer ones (PI. XIX,
fig. 10). In the simplest moss-fruits, such as that of
Phascum for instance, there ensues a repeated division of
the cells of the circumference by means of horizontal
septa, so that these latter cells appear only half as high as
those of the centre (PI. XXI, fig. 1, a). The cells of the
periphery now divide by diagonal septa, the outer ones
again by radial septa, and so on alternately, until the
entire thickness of the fruit-rudiment is attained. At the
same time division commences in the central cells of the
middle and lower portions of the fruit-rudiment by means
of septa parallel to the chord of the arc of the periphery,
alternating with radial septa. This division leads to the
formation of the string of elongated cells, which traverses
the axis of the seta (PL XXI, fig. 1).

In mosses with more complex fruit, such as Funaria
hygrometrica, and Gymnostomum pyriforma, the division

158 HOFMEISTER, ON

of the cells of the circumference by transverse septa first
occurs after the production of an entire row of vertical
septa, so that the string of elongated cells in the axis
of the organ is far thicker. Even in vigorous specimens
of Phascum, a division by a septum parallel to the chord
of the arc of the outer surface precedes the formation of
horizontal septa in the outer cells.

The above account of the division of the cells of the
second degree does not apply in its entirety to the oldest
of such cells. In the latter the above cell-multiplication
proceeds only to a certain point ; in the first two, three,
or four of such cells, only the radial vertical septum is
formed, and in the two three-sided cells thus produced, a
tangential septum only ; in the next the formation of radial
vertical septa occurs in the four cells of the circumference,
and the eight cells thus formed divide by septa cutting
the last-mentioned septa at an angle of 90°. Thus the cell-
multiplication progresses gradually upwards.

The thickness of the fruit-rudiment increases conse-
quently from below upwards ; it assumes the form of
a spindle-shaped cellular mass. As long as the multi-
plication of its apical cell continues, the active increase of
the cells in the direction of the thickness is always arrested
for some considerable distance beneath the apex (PI. XXI,
fig. 3, 3*).

In the mean time the cells of the ventral portion of the
archegonium increase actively : so far as they encircle
the fruit-rudiment this increase takes place only by divi-
sion by means of septa perpendicular to the outer surface,
but in the lower portion it is produced by septa turned
in all three directions. The cells also of the hitherto flat end
of the stem which bears the archegonia (both the impregna-
ted and the unimpregnated),* expand and multiply actively,
those in the middle more actively than those at the sides. By
this means the end of the stem becomes conical ; it bears at
its apex the impregnated archegonium, and on its inclined
surface the abortive archegonia and the paraphyses. This is

* In several species of Milium, which exhibit a very large number of arche-
gonia (as many as fifty) in one inflorescence, several archegonia are usually
impregnated.

THE HIGHER CRYPTOGAMIA. 159

the origin of the Vaginula, the formation of which commences
in Phascum and Bryum at a very early period, at the
time when the fruit-rudiment only occupies the upper two-
third parts of the archegonium (PI. XX, fig. 15 ; PI. XXI,
fig. 4; PL XXIII, fig. 3). In Sphagnum the vigorous in-
tercalary multiplication of the cells of the end of the
stem which bears the archegonia begins at a much
earlier period : even before the young archegonium has
attained its full number of cells. The very short fructify-
ing side-shoots of Sphagnum cymbifolivm and S. squarrosum
usually develope one, at the most two archegonia, with
a remarkably fully developed ventral portion, and a strongly
clavate apex. When the latter is about to burst the
number of the cells of the end of the stem which bears
the archegonia (and which in Sphagnum is conical) in-
creases, without any change occurring in the circumference
of the conical mass of tissue. Its upper surface bears rudi-
mentary leaves destined to develope themselves in the fol-
lowing summer, at the commencement of the ripening of
the fruit (PL XVIII, fig. 15).

By the continuous longitudinal growth of the fruit-
rudiment its lower end is pressed continually deeper into
the tissue of the lower part of the archegonium, until at
last it reaches the parenchyma of the vaginula, to the
base of which it penetrates. The pressure is caused by
the resistance which the arcuate portion of the archego-
nium underneath its neck exerts upon the apex of the
fruit-rudiment. The tissue of the stem itself resists the
further penetration of the lower end of the fruit-rudiment.
The ventral portion of the impregnated archegonium
which has become the calyptra, now usually assumes the
shape of a bell, in consequence, it would seem, solely of
the expansion of its cells (Phascum, PL XXI, fig. 24,
Gymnostonium, Eucalypta, Orthotrichum). The cells of
its inner tissue become dissolved, only the single layer of
the outer surface remaining (PL XXI, fig. 4). The hollow
cavity between the latter, and the fusiform fruit-rudiment,
is filled with watery fluid. The increased tension of the
side wralls of the calyptra, which is produced by the
sudden and considerable expansion of the median cells of

160 HOFMEISTER, ON

the fruit-rudiment, causes the calyptra to break away by a
circular fissure near its place of junction with the vaginula.
The calyptra is carried upwards by the rapid elongation of
the fruit-rudiment, upon whose apex it is placed.

At this period an active cell-multiplication commences
(especially in the direction of the thickness) in the upper
part of the fruit-rudiment, a little beneath the apex. The
cells of the apex itself take no part in this new production
(PI. XXII, fig. 6). When the repeated division of the
cells of the outer surface of the rudimentary fruit has in-
creased the diameter of the part nearly under the apex by
a certain number of cells (in Phascum cuspidatum, for
instance, to sixteen, in Gymnostomum pyriforme to eighteen)
an air-cavity in the shape of a hollow cylinder is formed
nearly under the outer side of the slightly swollen upper
end of the rudimentary fruit. This cavity divides the
axile portion of the rudimentary capsule from the peri-
pheral part, or capsule-wall. The .latter in most species of
Phascum has only three layers of cells (PI. XXI, fig. 5) ;
in Phascum bryonies and Archidium phascoides, it has only
two (PI. XXIII, figs. 5, 6, 8) ; in Gymnostomum pyriforme
it exhibits in its lower portion five, in its upper, three
layers of cells (PI. XXII, fig. 7).

The primary mother-cells of the spores originate in an
annular layer of cells of the axile portion of the rudimentary
capsule. In Phascum and Eucalypta this layer is the
second, in Gymnostomum and Fun aria the third, reckon-
ing inwards from the periphery of the central portion of the
young capsule, which central portion is surrounded by the
swollen, hollow, cylindrical air-cavity. The adjoining outer
cells divide at a very early period by septa parallel to the
axis of the fruit, and most of the inner ones of the newly-
formed cells divide by horizontal septa (PI. XXII, fig. 8).
In consequence of this Phascum and Eucalypta have two,
Gymnostomum and Funaria three layers of cells separating
the hollow, cylindrical air-cavity from the layer of primary
mother-cells (PI. XXI, fig. 5; PL XXII, figs. 7, 10).

When the young capsule of Phascum cuspidatum is from
i" to §"' in length, the primary mother-cells (in which by often
repeated cell-production the spores are formed) surround

THE HIGHER CRYPTOGAMIA. 161

the columella. The latter consists of a central group of
smaller cells with thinner walls, and a peripheral layer of
cells containing chlorophyll, which adjoins the mother-cells
of the spores. The cells of the outermost of the two layers,
which adjoin the primary mother-cells, are four times as
large as those of the inner layer.

The cells of the layer of the columella adjoining the
primary mother-cells, as well as those of the future inner
wall of the capsule, are distinguished in a remarkable
manner from all other cells of the theca, by the great concen-
tration of the cell-contents, which are rich in dextrine.
The large cells of the centre of the columella contain small
amyloid masses of peculiar structure : minute firm granules,
which become intensely blue under the action of iodine, are
embedded in a gelatinous mass, which assumes a light blue
colour under the same action.

The primary mother-cells, at this stage of their develop-
ment, contain a large central nucleus, which has usually
only one nucleolus, and somewhat transparent fluid con-
tents (PL XXI, fig. 5 ; PI. XXII, fig. 9). The remaining
contents of the cell, which consist of a thick fluid
mucilage rendered turbid by numerous granules, make it
somewhat difficult to distinguish the outline of the
nucleus.

The greater number of the primary mother-cells divide, as
the fruit becomes developed, by means of a longitudinal or
transverse septum perpendicular to the outer surface of the
theca; more rarely by means of a longitudinal septum
parallel to that outer surface (PI. XXI, fig. 6). The dis-
appearance of the primary nucleus of the cell, and the pro-
duction of two new nuclei, precede the appearance of this
septum. The contents divide into two halves, each of which
surrounds one of the newly-formed nuclei (PL XXI, fig. 6,<$) ;
at the point of contact these two halves secrete the new
cell-wall, which consists of a very delicate layer of cellulose
(PL XXI, fig. 6, a)*

Sometimes when the development of the fruit is very
active, the above division is repeated in the secondary

* The two halves represented in the figure have contracted under the in-
fluence of water, to which, in Phascum, they are very susceptible.

11

16.2 HOFMEISTER, ON

mother-cells. Usually, however, immediately after the for-
mation of the secondary mother- cells, the tertiary mother-
cells, i. <?., the spore-mother-cells, are produced.

Owing to the want of transparency of the cell-contents
the nucleus of the secondary mother-cells can with difficulty
be distinguished. It is, perhaps, impossible to make out
what part it plays in the formation of the spore-mother-
cells. A nucleus with a large nucleolus is very indis-
tinctly seen through the grumous contents of the perfect
tertiary mother-cell. The spore-mother-cells lie in twos,
very rarely in fours (PL XX, tig. 7), quite free and de-
tached in the inner cavity of the primary mother-cells. The
second condition can easily be looked upon as the result of
the suppression of the formation of the secondary mother-
cells. A long series of comparative measurements has con-
vinced me that the latter do not increase in size during or
after the formation of the spore-mother-cells, and if this be
so, the formation of the last-mentioned cells can only take
place by the occurrence of a considerable contraction of the
entire contents of the cell, either before or immediately
after its division into two halves, upon the entire surface
of which (two halves) cellulose is then secreted. I believe
that I have actually seen such a process of transition (PI.
XXI, fig. 9).

The membrane of the mother-cells, primary, secondary,
and tertiary, is coloured pale blue by iodine. When
brought under water its substance swells rapidly, espe-
cially that of the inner younger layers. The membrane
of the tertiary mother-cells swells the most, that of the
primary ones the least. This peculiarity of the wall of the
spore-mother-cell affords one of the most striking proofs
of the independent nature of the primordial utricle. The
spore-mother-cell, when placed in water on the stage of
the microscope, rapidly swells to double its original size,
its wall being excessively distended. The cell contents,
which are plainly surrounded by a thin layer of soft matter
very like a delicate membrane, swell slightly or not at all ;
they (the cell-contents) lie free in the inner cavity of
the cell in the form of a closed vesicle, surrounded by
watery fluid. Individual points of the primordial utricle

THE HIGHER CRYPTOGAMIA. 163

sometimes exhibit slow expansions and contractions similar
to those of many of the inferior animals ; for instance, the
smaller Ameeba3. It is especially in such cases that the
delicate mucilaginous membrane which encloses the cell-
contents may be most clearly observed.

By continued absorption of water the primordial utricle
becomes pressed laterally against the cell-wall ; the granules
which float in its fluid contents exhibit active molecular
motion. Ultimately, the cell-membrane is ruptured, usually
at the spot where the primordial utricle is in contact
with it, and the latter escapes through the fissure. It
then usually bursts, but occasionally I have seen the
primordial utricle glide out through the fissure of the cell
in the form of a closed, tightly stretched globular vesicle
(PI. XXI, fig. 8). The internal granules (consisting of
starch and a substance rendered brown by iodine), conti-
nued their active molecular motion, which stopped sud-
denly, when a drop of diluted watery tincture of iodine
was applied. The membrane of the primordial utricle
shrivelled up to some extent, and assumed a yellowish-
brown colour (PI. XXI, fig. 8, b).

In one instance I observed a very peculiar state of the
primordial utricle. As I brought the object under the
microscope, it floated freely in the form of a globular
vesicle in the interior of the swollen cell. Afterwards it
approached the cell-wall, and attached itself to one of the
sides, assuming the form of a slightly compressed sac
(PI. XXII, fig. 1.) Half the cell-cavity remained empty,
or at least contained only water. The primordial utricle
gliding up to the inner wall of the cell commenced a slow
rotatory motion.

It has been already mentioned that the walls of the
secondary mother-cells swell rapidly until they burst. If
a section of a capsule containing fully formed tertiary
mother-cells enclosed within secondary mother-cells is
placed under water, it often happens that all the spore-
mother-cells escape out of the ruptured secondary mother-
cells, and become dispersed in the water upon the slide.
At this stage of development of the capsule the fluid con-
tents even of the cells of the outer capsule-wall attract

164 HOEMKISTER, ON

water powerfully. If a thin section of these cells is placed
in water, very active currents may be observed over these
cells, and in their interior.

In Gymnostomum ovatum the affinity of the substance of
the walls of the tertiary spore-mother-cells for water is
even stronger than in Phascum cuspidatum. If these
cells are placed in water, the substance of the cell-mem-
brane is almost immediately distributed through the fluid,
so that the cell-contents remain behind, a shapeless, dis-
solving, round mass. In order to get a sight of these
thick cell-membranes, it is necessary to observe the cells
with the greatest promptitude immediately after they have
been prepared for the microscope. On rare occasions the
outermost lamella of these membranes holds together for a
somewhat longer period in the form of a sac open at one
end, after the rupture, by pressure, of the more highly
swollen inner layers.

The contents of the mother-cell of the spores of Phascum
divide into four portions, which after some time become
clothed with a stiff membrane, and shrivel up under the
action of alcohol. The first indication of this division
is the appearance of a transparent line in the turbid cell-
contents, passing transversely through the cell (PI. XXII,
fig. 2), or of two such lines cutting one another at right
angles (PI. XXII, fig. 3). The contraction of the contents
manifestly occurs for the first time after their division into
halves. The opacity of the cell-contents entirely prevents
the observation of the behaviour of the nucleus of the spore-
mother-cell during the formation of the spores.

The young spores lie in fours quite free in the mother-
cell (PI. XXII, fig. 4). Each spore exhibits a central
nucleus, with a manifest nucleolus (PI. XXII, fig. 5). The
cell-contents consist of proteine combinations, dextrine, and
starch- granules. Afterwards, when the formation of the
exosporium commences, (at which period the absorption of
the spore-mother-cells begins), oil- drops are visible in the
interior of the spore, which, as the spore becomes mature,
increase in number and size. During the time that the
spores lie free between the inner wall and the columella,
the cells of the innermost cellular layer of the former, and

THE HIGHER CRYPTOGAMIA. 165

of the outermost layer of the latter, abound with a saturated
solution of dextrine, in which the nucleus floats in the form
of a very sharply defined vesicle with less highly refractive
contents.

During the secretion of the exosporium, the walls of
those cells which are adjacent to the columella towards the
apex of the fruit assume a deep-brown colour. It is in
these cells that the partial disruption of the theca com-
mences, by means of which the spores, which in the mean
time have fully ripened, become free.

In Gymnostomum pyriforme, the multiplication of the
cells of the upper part of the spindle-shaped rudiment of
the fruit extends downwards far beyond the base of the
future fruit. In this way an apophysis originates, which in
the earliest stages of development far exceeds the fruit in
size. After the separation of two annular layers of cells
beneath the apex of the rudimentary fruit, by which means
the vacant space between the outer and inner wall of the
theca is formed, individual cells of the inner side of the
outer wall grow so as to form chains of cells, the uppermost
of which remain in connexion with the upper surface of the
inner wall (PI. XXII, % 7).

In the very young capsule of Gymnostomum pyri-
forme, at the time of the division of the cells which
adjoin the outer and inner sides of the primary
mother-cells, the latter have the form of very flat plates
parallel to the axis of the fruit (PI. XXII, fig. 8). During
the further development of the theca, the transverse dia-
meter of these cells increases considerably. A proportion-
ably large nucleus with a large nucleolus becomes visible,
floating freely in the fluid contents (PI. XXII, figs. 9, 10).
The length of the cell soon considerably exceeds its height
and width.

At this time two new globular nuclei appear in the place
of the vanishing primary nucleus (PI. XXII, fig. 11). Half
of the granular mucilaginous cell-contents accumulates
round each of them ; two globular masses of protoplasm
are formed, which, after secreting cellulose over their entire
surface, constitute the free spherical mother-cells of the
spores (PI. XXII, fig. 12).

166 HOFMEISTER, ON

If the primary mother-cells are unusually long or wide,
they divide, according to the ordinary method of cell-multi-
plication, before the formation of the spore-mother-cells.
Two of such primary mother-cells then adjoin one of the
cells of the neighbouring cellular layers (PI. XXII, fig. 12).
In rare instances, four spore-mother-cells are found in one
primary mother-cell (PI. XXII, fig. 12*).

The walls of the primary mother-cells, which at an early
period are very sensitive to the action of water, become
more so after the formation of the spore-mother-cells. If
a longitudinal section of a fruit in this stage of development
be placed in water upon a slide, the walls of the primary
mother-cells immediately burst, and the spore-mother-cells
are dispersed over the field of view. It is necessary to
examine the preparations in some saline solution. A solu-
tion of carbonate of ammonia is the most useful.

In the natural course of things, the dissolution of the
walls of the primary mother-cells follows soon after the
formation of the spore-mother-cells. The spherical spore-
mother- cells then lie free between the columella and the
inner wall of the theca. Numerous mucilaginous granules
surround the central nucleus, the substance of which is as
clear as water (PI. XXII, fig. 13).

During the further development of the fruit, the nucleus
of the spore-mother-cell approaches the cell-wall, and usu-
ally assumes a lenticular shape. The granules of the fluid
contents of the cell accumulate at its middle point, so as to
form a spherical group (PI. XXII, f. 14), in which the
nucleus is sometimes partially embedded. This accumula-
tion of granules divides afterwards into two halves (PI.
XXII, fig. 1 5) ; a spherical nucleus may often be seen in
each of these granular masses (PL XXII, fig. 16). Each of
the elongated groups of mucilage and granules divides anew
into two parts ; and then four spherical accumulations of
coarsely granular protoplasm are found in the mother-
cell. They are usually arranged at the four corners of
a tetrahedron (PL XXII, figs. 17, 18), and very seldom
lie in the same plane (PL XXII, fig. 19). Each of them
contains a nucleus. The outline of the primary nucleus
of the mother-cell becomes less and less distinct during

THE HIGHER CRYPTOGAMIA. IG7

thcss processes, and at last that nucleus disappears alto-
gether.

A spore is formed round each of the four secondary
nuclei. The four spores do not nearly fill the mother-cell.
A viscid fluid jelly fills the space between them (PI. XXII,
figs. 20, 21).

A layer of similar jelly is previously visible, forming
the innermost layer of the membrane of the mother-cell ; a
bright space is formed between the firm lamella of the
membrane and the boundary of the cell-contents (PI. XXII,
figs. 17, 19).

The first stages of development of the spore-mother-cell
of Funaria hygrometrica resemble those of Gymnostomum
pyriforme. Two secondary nuclei are formed outside the
primary nucleus of the cell in the middle of an accumula-
tion of granular mucilage (PI. XIX, fig. 12). After-
wards four nuclei appear in the place of the two (PI. XIX,
fig. 14). The primary nucleus, which has become paler, now
disappears. Suddenly the mother-cell divides into four
parts of the form of a tetrahedron with a convex basal surface.
This division is produced by six septa passing through
each two of the four secondary nuclei. These four divi-
sions constitute the special mother-cells, which in this
genus have firm rigid walls, which at first are very thin
(PI. XIX, fig. 15). After the walls of these special-
mother-cells have become considerably thickened by the
deposition of gelatinous layers, a spore is produced in
each of them, which, at its first appearance, entirely fills
the mother-cell (PI. XIX, fig. 16).

The formation of the spores of Funaria more nearly
resembles that of the pollen of phsenogamous plants, than
the spore-development of Phascum, the similar process in
Eucalypta, and that in Gymnostomum pyriforme. The
material differences in the process of development of the
spore-mother- cells in plants which are in other respects
so closely allied, may, without hesitation, be considered
as an indication of the fact, that the greater or less degree
of firmness of the walls of the special mother-cells is
an unimportant circumstance. The essential phenomenon
in the formation of four spores or pollen -cells in the

168 HOFMEISTER, ON

interior of a mother-cell, is the contraction of the contents
of the mother-cell (which contraction usually follows
the division into two parts, or the repeated division into
two parts of such contents), and the formation round
the contracted mass or its divided portions of a new mem-
brane, not attached to the inner surface of the membrane
of the mother-cell. In plants, where the contents of the
mother-cells divide into several portions before the con-
traction, the question whether special mother-cells with
firm rigid walls are developed or not, depends simply
upon the greater or less firmness of the substance which
must be secreted by the cell-contents in order that the
latter may be able to contract into a smaller space. This
substance is always gelatinous, and usually tolerably firm.
The thin, fluid nature of the jelly in Gymnosiomum pyriforme
forms a gradual transition to the state of circumstances
found in Phascum, where the fluid substance which
is found between the inner wall of the mother-cell and the
contracted portions of the contents, behaves under iodine
just like pure water. The latter cases seem to show that
the contraction of the cell- contents depends upon an
innate vital action, and not upon a mechanical compres-
sion (accompanied by the withdrawal of water), caused by
the distension of the innermost lamella of the membrane of
the mother-cell.

A great uniformity prevails in the process of develop-
ment of the fruit of mosses so far as regards the most
prominent features, viz., the cell-multiplication of the
young fruit-rudiment, the separation of the sporiferous
cellular layer from the remaining tissue of the theca, and
the separation of the outer wall of the capsule from the
inner one. The deviations from this process exhibited
in Arclddium p/iascoides, the ripe fruit of which is itself
remarkable, are, therefore, the more surprising. These
deviations are reducible to two: — 1. Spores are developed
by one cell only of the hollow cylindrical layer whose
cells in other mosses become, one and all, primary mother-
cells : — 2. This cell and the daughter- cells produced by
the division of its contents, gradually displace the whole
of the inner tissue of the capsule. The peculiarities of

THE HIGHER CRYPTOGAMIA. 169

Arcliidium are, therefore, not altogether a departure
from the typical development of moss-fruit, but are rather,
with regard to the first point, a diminution, and with
regard to the second, an increase, of the growing power
usual in the allied forms.*

The antheridia do not differ essentially from those
of the species of Phascum. The spermatozoa are rather
large ; they exhibit, very clearly, the two cilia shown by
Thuret, to exist in the mosses generally. The structure of
the unimpregnated archegonia is distinguished from that in
Phascum only by the slight extent of the longitudinal deve-
lopment of the lower part (PI. XXIII, fig. 1). I cannot
confirm P. W. Schimper's statement as to the pleuro-
carpus fructification of Archidium. I find rather that the
position of the archegonia and fruit exactly agrees with
that which obtains in Phascum. The germinal vesicle is
usually attached to one of the side walls of the central cell
of the archegonium (PI. XXIII, fig. 1). After impregna-
tion the germinal vesicle enlarges to a remarkable extent,
considerably expanding the ventral cavity of the archego-
nium, and pressing together the adjoining cells (PI. XXIII,
fig. 2). The cell-succession of the fruit-rudiment is that
which is common to all mosses, depending upon the re-
peated division of the apical cell, by septa inclined alter-
nately in two different directions (PI. XXIII, fig. 3).
The upper half of the fruit-rudiment soon increases in
thickness, and ruptures the calyptra on one side, dis-
placing it laterally (PI. XXIII, fig. 4).

In the interior of the fruit-rudiment, underneath the
second cellular layer (reckoning from the outside inwards),
layers of cells parallel to the outer surface become discon-
nected : an intercellular space is formed, having the shape
of an ellipsoidal covering, truncate at either end (PI. XXIII,

* Schimper attempted to explain the nature of the ripe fruit of Arcliidium
(PL xxiii, f. 11) by supposing that the whole of the interior of the fruit-rudi-
ment became converted into mother-cells, and that only one spore was formed
in each of them ('Reek, sur les Mousses,' Strassburg, 1848, Bryol. Europ.
1st ed., p. 2). In the ' Vergl. TJntersuchungen,' I have objected to the above
view, on the ground that imperfectly ripe spores exhibit a junction in fours.
The observations given above (which were first published in the ' Reports of
the Royal Academy of Saxony,' 1854, p. 102) were made upon living plants,
kindly furnished by Messrs. Schultz, Bitsch, Tulasne, and Durien.

170 HOFMEISTEll, ON

figs. 5, 6, 7). This is exactly the process which in all
mosses causes the separation of the outer capsule-wall
from the inner portion.

One of the cells of the interior of the capsule grows to a
considerable extent, pressing the adjoining cells together.
Its walls become thickened, and its contents rich in
granular mucilage (PI. XXIII, fig. 5) . This cell is the sole
primary mother-cell of the spores. Its primary position is
always excentrical, separated by two layers of cells from
the hollow cavity which adjoins the inner surface of the
outer capsule-wall. Its vigorous power of growth con-
tinues whilst the surrounding tissue becomes disintegrated
and dissolved. It now lies quite free in the cavity of the
capsule, and falls out of the opened capsule without assist-
ance. Four freely-floating mother-cells of the second
degree are produced in its interior (PL XXIII, fig. 7),
each of which divides into four special mother-cells (PI.
XXIII, fig. 8). Each of the latter produces one spore,
so that the whole number of spores is sixteen. I have met
with no exception to this in my numerous investigations.

The diameter of the newly-formed spore measures only
one-sixth that of the ripe one. A delicate exosporium
is distinguishable even in the earliest stages of develop-
ment (PI. XXIII, fig. 9). Afterwards it increases consider-
ably in thickness, even before the entire dissolution of the
mother-cells and the special mother-cells.

The inner capsule wall, and the inner cellular layer of
the outer wall, are present for some time after the forma-
tion of the spores. These masses of cells are displaced, as
far as the outermost cellular layer of the (now spherical)
capsule, by the gradual growth of the spores. The mem-
brane of the primary mother-cell remains to the last, en-
closing all the spores. It is the membrane spoken of in
the ' Bryologia Europoea ' as the delicate spore-sac.

Few processes in the vegetable kingdom are so
thoroughly understood as the germination of the spores
of mosses, the production of leafy axes from individual cells
of the confervoid pro-embryo. The admirable observa-
tions of Schimper* have entirely solved the last remaining

* ' Recherches sur les Mousses/ St.rasburg, 1848.

THE HIGHER CKYPTOG AMIA. 171

difficulty. The investigations of Hedwig and his successors
can be so easily repeated in many species, as, for instance,
Funaria hygrometrica and Barbula muralis, that it would
be waste of time to give a description of the phenomena.
I will mention only some peculiarities which are not so
well known.

The threads of the pro-embryo, whether they arise
from the development of a spore, or from a cell of
the surface of the stem or of a leaf*, exhibit in many
species two very different modifications of development.
The principal ramifications of the confervoid rows of cells
are filled with assimilated matter, and contain very
numerous chlorophyll bodies ; their longitudinal growth,
which results from repeated transverse divisions of the
terminal cell, is unlimited. The lateral ramifications of
these principal branches of the pro -embryo have only a
limited growth ; the terminal cells, when they cease to
divide, assume a conical form. Moreover the lateral
branchlets ramify in a complicated manner. Their con-
tents are far less concentrated, their transverse diameter
narrower, their chlorophyll more inclined to a yellowish
tinge than is the case with the principal branches. These
latter only are capable of producing true germs or leafy
axes. The principal branches of the pro-embryo may,
perhaps, be compared to stems ; the lateral branches with
limited growth to leaves. These phenomena are very
remarkable in the pro-embryo of Racomitrium ericoides.
Here, owing to their peculiar habit, the lateral shoots of

* I wish to add a few words as to the meaning of the expression " pro-
embryo." By the word "embryo," is meant the bud capable of developing
leaves and roots. Thus, we speak of the embryo of the onion, the potato, the
hop. Now, when we find in the vegetable kingdom organs which differ from,
and are of an essentially simpler structure than the leafy stem-rudiments which
afterwards spring from them, but which must normally and necessarily in the
course of their development produce embryos, I consider that I am justified in
calling these organs " pro-embryos." Thus, I designate as a pro-embyro the proto-
nema of a moss, whether it owes its origin to the germination of a spore or to the
independent development of an individual cell of the leaf- bearing plant. I treat
in the same manner the suspensor of Selaginella, of the Coniferse, and of the
phanerogamia. On the other hand, I do not designate as a pro-embryo the
body which is produced directly from the germination of the spores of ferns,
Equisetacese, Rhizocarpese, and Lycopodiacese, and which bears antheridia and
archegonia, usually only the latter. This organ I call a " prothallium."

172 HOFMEISTER, ON

the principal branches, bring to mind most forcibly the
leaves of Trichocolea tomentella. The pro-embryo of Phas-
cum serratum is also remarkable, especially when it
originates from the lower leaf-axils of developed plants.
It is a fact, noticed especially by Nageli, that the shoots of
the pro-embryo are often subterraneous for a considerable
distance 5 the transverse septa of such subterranean threads
of the pro-embryo are not perpendicular to their cylindrical
outer surface, but strongly inclined to it. The pro-
embryonal threads of Schistostega osmundacea creep about
for a considerable distance in the damp sand upon which
this delicate moss is accustomed to vegetate. These sub-
terranean rows of cells have such a narrow cavity, and their
fluid contents are so transparent, and so deficient in
granular matter, that they may be mistaken for some of
the most delicate microscopical forms of moulds. When
the terminal cell of such a thread is exposed to daylight, it
immediately swells to a spherical form, and some beautiful
emerald green chlorophyll-bodies are formed in its fluid
contents. It would seem that a single chlorophyll-body is
first formed, which is then increased by self-division
(PL XVIII, fig. 16). The multiplication of the cells of the
subterranean green portion of the pro-embryo, takes place
by the continual division of its cells by means of transverse
septa. The process is somewhat peculiar. The new septum
does not pass through the mother-cell transversely, but the
division commences by the protrusion, from the apex, of a
small swelling which is at first hemispherical. The upper
part of this protuberance increases rapidly in circumference,
and becomes spherical ; the lower part, on the other hand, — ■
viz., the place of junction of the protuberance with the
mother-cell, — widens to a very small extent, or not at all.
Finally, when the size of the protuberance has nearly reached
that of the mother-cell, a transverse septum is produced at
the point of constriction, which cuts off the protuberance
from the mother-cell (PL XVIII, fig. 16). Some time
before the appearance of this septum, the first chlorophyll-
vesicles are perceived within the protuberance. Usually
only one such vesicle is at first visible, and the first symp-

* ' Zeitschrift fur Wiss. Bot./ Hft. 2, s. 172.

THE HIGHER CRYPTOGAMIA. 173

toins of it appear to be the production of colouring matter
within a spherical drop of semi-fluid mucilage. It is cer-
tain that no chlorophyll-vesicles pass from the original cell-
cavity into the enlarging protuberance. The single chloro-
phyll-vesicle often attains a very considerable size : in other
cases four or more chlorophyll-vesicles are found in the
protuberance before the formation of the septum which
divides it from the original cell-cavity. Probably these
have been produced by the repeated division of the original
individual chlorophyll-vesicle. The number of chlorophyll-
vesicles in the recently-formed cells of the pro-embryo is
very frequently four. Older cells usually exhibit a larger
number. It is but rarely that the chlorophyll-vesicles are
agglomerated in the middle of the cell : when this is the
case, the condition appears to me to be a diseased one.

The well-known metallic lustre which marks the spots
overgrown by Schistostega is not caused by the chloro-
phyll-vesicles, but is fully accounted for by the spherical
form of the individual cells. Dewdrops upon spiders' webs
produce a precisely similar optical appearance.

I could not discover any nuclei in the dividing pro-
embryonal cells of Schistostega. My observations having
been made whilst travelling, I had not any tincture of
iodine at hand.

Some of the older observers entertained curious opinions
as to the influence of the moniliform rows of cells of the
pro-embryo upon the development of the young plants.
The most peculiar notion is that of Hiibener, who says,
" These bodies afford, by reflexion, the light which is neces-
sary for the life of Schistostega ; and in this way, as Esch-
weiler has very correctly remarked, they represent the
moons of the vegetable kingdom." The glimmer of the
protonema of Schistostega cannot be explained by phos-
phorescence. The plant never shines in the dark, even
although previously exposed to a rather intense light, such
as that reflected from a white cloud. The direct action of
sun-light almost immediately destroys the vitality of the
cells. This unusual sensitiveness to the rays of the sun is
common to a number of other mosses also ; for instance,
Calypogeia Trichoman es.

174 HOFMEISTER, ON

It is a widely-spread notion that the pro-embryo of
mosses, irrespective of its entirely different physiological
nature, is distinguishable from the prothallium of ferns by
the fact that the former consists of confervoid cellular
threads, the latter of an ulva-like cellular superficies. I
was much surprised, therefore, when I found that certain
crisped vegetable formations resembling the prothallia of
the Equiseta or plants of Anthoceros punctatus and which
had grown as weeds amongst some unsuccessful sowings of
Lijcopodium Selar/o, proved to be the pro-embryos of a
moss, Sphagnum cuspidatum.

Schimper (' Rech. sur les Mousses') has figured the
ramified rows of cells which are the first products of the
development of Sphagnum-spores when sown in water.
Afterwards the same observer noticed certain shoots pro-
ceeding from short lateral branches, during the vegetation
of the pro-embryo in water. These shoots are very pro-
bably the rudiments of leafy branches. When germinating
upon moist earth, one of the ramifications of the thread-
like pro-embryo becomes a cellular superficies (PL XVIII,
figs. 6, 8). The disposition of its cells fluctuates between
an arrangement in pairs and a simple cross-bar arrange-
ment ; this is caused by the repeated division of a single
apical cell, by means of septa perpendicular to the surface,
turned alternately to the right and to the left. The former
kind of cell-succession usually prevails. The copious rami-
fication of the pro-embryo appears sometimes truly, some-
times spuriously, dichotomous ; it is rendered indistinct by
the appearance of numerous adventitious basal shoots. A
vigorous pro-embryo forms a tangled tuft which it would
be lost labour to attempt to reduce to any regular system
of ramification (PL XVIII, fig. 5).

Two phenomena distinguish these pro-embryos in a
remarkable manner from the prothallia of ferns and Equi-
setaceae. The crisped cellular surfaces are single throughout
their whole extent even after ten months' growth. The
parenchymatal tissue, from which the female organs of
reproduction are produced in the green prothallia, is never
seen. The base and the side-edges of the lobes of the pro-
embryo are furnished with thread-like processes which are

THE HIGHER CRTFTOGAMIA. 175

branched and divided by septa, differing herein consider-
ably from the simple radical threads of prothallia. Such
of "the above-mentioned processes as are rich in chlorophyll
are divided by septa perpendicular to the longitudinal axis ;
those which are deficient in chlorophyll, by oblique septa.
These widely-creeping cellular threads have the capacity of
producing new expanded pro-embryos, by enlargement and
division of the terminal cells.

In individual cells of the lobes of the embryo, usually in
those very near the base, a multiplication commences differ-
ing essentially in direction and in kind from that hitherto
spoken of. A hemispherical knot of cellular tissue is pro-
duced, which by degrees becomes cylindrical, and which,
developing, as it does even at an early period, some rudi-
mentary leaves, may be recognised as the shoot of a moss
(PL XVIII, fig. 10). The arrangement of the cells of the
leaves brings to mind Sphagnum; a suspicion which is
reduced to certainty by the characteristic thickening layers
of the leaf-cells which appear in the fifth leaf. I find the
phyllotaxis to be from the beginning | (PL XVIII, fig. 10).
Rootlets springing from the leafy root are not to be found
in Sphagnum acutifolium.

Hedwig's observations* were the commencement of an
accurate knowledge of the sexual reproduction of mosses.
He pointed out the antheridia as the male organs, recognised
their structure, and observed the escape of their contents.
He figured the archegonia as flask-shaped bodies, closed
when young, and afterwards opening at their apex. He
also pointed out the conversion of the ventral portion of the
archegonium into the calyptra, and the formation of the
fruit-rudiment within it. Lastly, he showed by experiment
that the spores of the mosses are their true seeds. He
sowed the spores of Gymnostomum pyriforme, and observed
their germination, and the development of the inner spore-
membrane into a cellular thread, or, as Hedwig called it, a
cylindrical cotyledon (1. c, 153, pi. xvi, fig. 9). After some
time scales were seen on these threads, which scales, when
examined with the microscope, proved to be young plants,
the bases of which were attached to branched pro-embryonal

* 'Tlieoria generatiouis,' ed. ii,p. 134, et seq.

176 HOFMEISTER, ON

threads. The same was the case with Ftmaria hygrometrica.
The production of leafy plants out of pro-embryonal threads
was considered by Hedwig's followers to arise from the
amalgamation of several threads of the pro-embryo, so as
to form the leafy stem (see Schleiden, ' Grnndzuge,'
2nd edit., vol. h\, p. 60), an error which was grounded
upon the fact that numerous cells of the base of the
young leafy plant usually grow into new pro-embryonal
threads, the Brtitkeinifaden of Nageli. Nageli clearly
explained the development of the leafy axis out of the
pro-embryo. He showed* that at the commencement
of the formation of the moss -stem, the terminal cells of
individual branches, or of the principal axis of the spores
or brood-germ-threads, expand, and, through division by
means of septa inclined in different directions, become con-
verted into a cellular body, which afterwards produces
leaves, and thus indicates the rudiment of a stem. The
results obtained by Nageli have been extended by P. W.
Schimper (' Rech. sur les Mousses,' Strassburg, 1848,
ss. 1 — 4) to such a number of different species, that there
is no doubt of their general application.

The spermatozoa of the mosses, and (with the exception of
an imperfect observation of Bischoff's,) of the cryptogamia
generally, were discovered by Unger in 1834 ('Mora,'
1834, p. 145 ; more fully in ' N. A. A. C.,' xviii, pp. 2,
690, 790). Unger describes the spermatozoa as con-
sisting of a thick body, and a thin thread-like prolonga-
tion, which goes in advance when the body is in motion,
and is of a spiral form.f The motion of the spermatozoa

* ' Zeitschrift f. wiss. Bot.,' 2, 168.

f ' Bischoff, Kryptog. Gewachse ' (Nurnberg, 182S), p. 13 note, mentions
that lie has always noticed in freshly-opened globules (antheridia) of Chara
hisjnda, a medley of numberless infusoria. They appeared to consist of small
dark points, which were connected by transverse lines like little strings. They
exhibited a continuous tremulous motion, by means of which the individual
points, with their stems, revolved round one another. Bischoff was doubtful
whether these "infusoria" originated from cellular threads in the interior of the
antheridia. It is hardly necessary to remark that Bischoff's dark points are
only the optical sections of the turning points of the spiral spermatozoon.
Schmidel's observations on Fossombromia (Ic. pi., p. 85) and those of Nees v.
Eseubeck ('Flora,' 1822, p. 34) on Sphagnum afford still less claim to the dis-
covery of the Spermatozoa, inasmuch as both observers only saw the motion o.
the escaped contents of ruptured antheridia, but did not distinguish the forms
of the motile bodies.

THE HIGHER CRYPTOGAM EA. 177

is accompanied by continual revolution of the body round
its own axis : that is, round the axis of the spiral. Be-
fore maturity the spermatozoa are enclosed in quadran-
gular cells. Later observations have only added one fact
to those of Unger, viz., that the thin fore- end of the
spermatozoon bears two long oscillating cilia (Thuret,
' Ann. Sc. Nat./ ii Ser., vol. xiv, p. GS, and iii Ser., vol.
xvi, p. 73; Schimper, 'Rech. sur les Mousses/ pi. xv,
tigs. .25 — 29 ; ' Mem. sur les Sphaignes/ pi. viii, figs. 23 —
25). Unger noticed the cuticle of the antheridia of
Sphagnum, but could not decide whether the structureless
membrane, which is capable of being detached from the
chlorophyll-bearing cells of the covering layer, was on
the outside, or on the inside of those cells. He was in-
clined to assume the latter. Schleiden seems to have
fallen altogether into the mistake of supposing the cuticle
to be the membrane of a large central cell of the anthe-
ridium surrounded by the covering layer, for he alleges
(' Grundzuge/ ed. iii, p. 577), that this organ in Sphag-
num is a stalked oval sac, formed of a large central cell,
and a surrounding cellular layer. This erroneous state-
ment has been entirely refuted by P. W. Schimper (' Rech.
sur les Mousses,' p. 52), by means of the history which
he gives of the development of the antheridia, and also
by his accurate description of the anatomical structure
of these organs when they are mature and ruptured.

In the same manner as he has done in the case of the
antheridia, P. W. Schimper has recognised the rudi-
mentary formation of the archegonia, by means of the di-
vision, by septa inclined in different directions, of an out-
wardly-protruding papillary cell of the external surface
of the apex of the stem. This division is continually re-
peated in the apical cell of the cellular body, as it gra-
dually becomes cylindrical.

Until the publication of my observations, however, the
continental botanists attained no greater knowledge of the
structure of the archegonium when ready for impregnation,
than was possessed by Hedwig.

In the mean time, in the year 1833, Valentine had dis-
covered the simple rudimentary cell of the moss-fruit, in

12

178 H0FME1STER, ON

the interior of the archegonimn ('Trans. Linn. Soc./
vol. xvii, p. 465). He succeeded in detaching this
cell (p. 466). He recognised it also in archegonia, whose
apices were still closed, but failed to discover it in Bryum
roseum, which in England often bears healthy archegonia,
but rarely fruit. He describes the development of the
rudimentary cell of the fruit as follows. " Soon after the
opening of the upper extremity of the style, another cell is
formed on the upper surface of the first. The two adhere
firmly, and may be dissected together. Presently another
cell is formed, either on the upper surface of the second, or
on its side ; then appears another, and so on. * * The
base of the style increases not by distension, but by
addition of fresh matter. * * The fusiform mass within
passes its conical extremity deeper and deeper into this
tissue, until at last it reaches the branch itself." Valentine
observed further that after the separation of the calyptra
from the vaginula, the seta increased in growth only at the
apex, and he figures accurately the separation of the outer
capsule-wall from the inner, by the formation of an annular
intercellular space.

Strange to say these observations of Valentine have
remained to this day wholly unknown in Germany and
France. They are not mentioned by De Candolle
(' Organographie vegetale,' ed. ii, vol. ii, p. 146) ;
Treviranus (' Pflanzenphysiol,' vol. ii, p. 46); Meyen
('System d. Pflanzenphys.,' vol. hi, p. 385); Scbleiden
(' Grundziige,' ed. ii, vol. ii, p. 68) ; or P. W. Schiin-
per ('Rech. sur les Mousses,' p. 67). I was myself
ignorant of them when I published my observations upon
the subject in'Botan. Zeit.,' 1849, p. 798, and in the
'Vergleichende Untersuchungen/ p. 69. Mohl in
Wagner's ' Handworterbuch der Physiol,' vol. iv (1853),
p. 279; P. W. Schimper, 'Mem. sur les Sphaignes (1859),
p. 10; and Gottsche, 'Botan. Zeit/ (1858), supplement,
p. 42, make no mention of Valentine's discoveries.
Valentine himself was far from appreciating the importance
of his own observations. He expressly disputes Hedwig's
views of the sexuality of mosses. He says " If sexes are
to be found in mosses they must be sought in the theca

THE HIGHER CRYPTOGAMIA. 179

(I.e., p. 777). The sporules of mosses and of all cellular
plants are analogous to the pollen of the vasculares." I can
claim as my own the account of the origin of the germinal
vesicle, of the dependence of its development upon the fact
of its impregnation, and the proof of the conformity between
the process of formation of the moss-fruit, and that of
the embryo of the vascular cryptogams, of the Coniferae,
and of the phanerogamia.

The first accurate account of the development of the
moss-capsule was given by H. v. Mohl, ('Flora,' 1833,
p. 1 ; ' Vermische Schriften,' p. 72). He places in a very
clear light the relation of the columella of Sphagnum yracile
to the two walls of the capsule, of the apophysis, and
of the peristome. The original homogeneity of the cel-
lular tissue of the young, few-celled fruit-rudiment, has
often been noticed by Bischoff {e.g., in 'Nova Acta,' vol.
xvii, p. 917). The development of the spores in fours
in one mother-cell, was pointed out by Mohl (1. c, p. 72).
Lantzius-Beninga showed (' De evolutione sporidiorum
in capsulis muscorum/ Gottingen. 1844, pp. 7, 11, 17),
that a single annular cellular layer of the interior of the
capsule represents the primary mother- cells of the spores,
and that the mother-cells, in which the spores originate,
are formed out of these primary mother-cells, by their
repeated division into two parts. He recognised, in many
instances, the free state of the mother-cells within the
primary mother-cells, as for instance, in Orthotrichum
speciosum, Trichostomum pallidum, and Gymnostomum
pyriforme ; and he discovered that the membrane both
of the primary mother-cells and of the mother-cells
became blue with iodine. In a later work, ' Bot. Zeit./
1847, p. 17, and more clearly in ' Nova Acta/ vol. xiv,
the same observer gives an admirable account of the anato-
mical structure of the perfect moss-capsule, especially of
the peristome, which up to that time had been almost en-
tirely misunderstood. Lantzius-Beninga stated that the
teeth of the peristome (except in Splachnum and Polytri-
chum,) do not consist of perfect cells, but that during the
development of the peristome-teeth, a partial thickening
occurs in the walls of the cells belonging to a conical

180 HOFMEISTER, ON

enveloping layer found in the interior of the upper conical
part of the capsule, within and beneath the layers which
afterwards fall off in the form of the operculum. The
thickening of the cell-membranes always occurs on both
sides. When a thickening takes place in the outer wall
of a cell which is occupied in forming the peristome, then
a portion, exactly corresponding in extent and form, of
the inner wall of the cell adjoining it on the outside becomes
thickened. When the thickened portion of the peri-
stome-cell is found on the wall which is directed towards
the axis of the capsule, then the corresponding portion of
the outer wall of the neighbouring cell adjoining it on
the inside, is thickened in like manner. These thick-
enings have usually the form of longitudinal stripes, and
are so arranged in each of the cells which help to form the
peristome, that they look like direct prolongations of the
stripes of the wall of the cell next below. When the
thickenings of the peristome-cells fill up the adjacent angles
of two laterally adjoining peristome-cells which are bounded
on the outside or on the inside by a cell of double width,
then the thickening of the wall in this wide cell occurs in
the form of a median stripe, which has the width of the
two corner stripes of the smaller neighbouring peristome-
cells. In the formation of the teeth of a moss with a single
peristome the outwardly-directed walls only of the peris-
tome-cells (and the corresponding mural stripes of the cells
adjoining on the outside) are partially thickened. In
mosses with double peristomes the inwardly-directed walls
of the peristome-cells are also thickened. When the cap-
sule becomes mature, the cell-walls which have remained
unthickened become torn during the separation of the
operculum from the capsule, and the thickened longitudinal
stripes remain as the peristome teeth. In Splaclmum and
Polytrichium the peristome-cells are thickened on all sides ;
in Splaclmum however the thickenings are irregular, those
which are directed outwards being much the strongest.

Some interesting observations of Bruchs have very lately
been published. Gumbel's observations have shown the
occurrence of abnormal fruitin mosses ('Nova Acta,' vol. xxiv,
p. 652). Those portions of the latter observations which

THE HIGHER CRYPTOGAMIA. 181

relate to the production in Milium serratum of two capsules
upon one seta, and of two capsules upon one apophysis in
Bryum aryenteum, and Splachnum vasculosum, seem to in-
dicate the possibility of a bifurcation of the growing upper
end of the fruit-rudiment. Those portions which relate to
the discovery of two fruits and two fruit stalks underneath
one common calyptra in Polytrichum juniperinum and of
two stalked fruits upon one seta in Hypnum plumosum, ap-
pear to point to the existence in the central cell of one and
the same archegonium, of two germinal vesicles capable of
impregnation. There is hardly a doubt of the occurrence
of such a polyembryony, the development of which however
must assume a different form, when it is considered that
(1. c., p. 653) the case of an amalgamation of two capsules,
each furnished with a peristome, has been observed in
Hypnum lutescens. The mouths of the two capsules are
turned to one another, the smaller one having grown up
upon the larger one. Both are united by a median
process.

In order to arrive at a perfect proof of the sexuality of
mosses, it is desirable that hybrids between different species
should be artificially produced : i. e. that fruits should be
obtained by the impregnation of the archegonia of one
species by the antheridia of another. Bayrhoffer suggested
that some mosses found by him growing wild were hybrids
between Gymnostomum pyriforme and fasciculare on the
one side, and Funaria hyyromctrica on the other side (see
Braun's ' Verjiingung,' p. 330). I have not yet succeeded
in producing such hybrids experimentally, although I
brought together antheridia! plants of Gymnostomum pyri-
forme and plants of Funaria hyyrometrica with their anthe-
ridial shoots cut off. The mutilated plants of Funaria
hyyrometrica always perished. This is however no reason for
giving up the attempt. By changing the method of culti-
vation the right one will probably be attained at last which
will lead to the desired result.

CHAPTER VII.

FERNS.

1. Their germination. — The spores of ferns usually
exhibit a tolerably thick, brittle, outer membrane, which is
furnished with prominent linear markings, or with wart-
like protuberances. When exposed to moisture and warmth
the inner membrane swells and ruptures the brittle outer
shell : this rupture usually occurs at the point of junction
of those three prominent lines of the outer membrane which
correspond with the lines of contact of the spore with the
three sister-spores which originated in the same mother-
cell and which, with the spore, formed a tetrahedron. In
the spores of those species in which the spore- mother-cell
divides into four cells having the form of quadrants of a
sphere and lying in one plane (which spores when ripe have
the shape of an elongated kidney) the exosporium usually
bursts by a longitudinal fissure, the course of which in like
manner corresponds with the line of contact of the spore
with its sister spores ; as for instance in Platycerium
alcicorne (PI. XXIV, fig. 1). A portion of the inner
membrane protrudes through the fissure of the exosporium,
and some chlorophyll-bodies are formed in this protruded
portion. The latter is soon afterwards separated by a par-
tition from that portion which remains inside the outer
membrane. In the outer of the two newly formed cells
the transverse division is repeated ; it usually occurs several
times (from three to five) in the terminal cell, so that the
young prothallium is converted into a row .of cells (PI.
XXIV, fig. 1). Sometimes the undermost cell, the one
which adjoins the exosporium, becomes considerably elon-

HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 183

gated ; as may be observed in Asplenium septentrionale
(PI. XXIV, fig. 3). In most cases however this elonga-
tion does not occur. I have never seen it in Picris aguilina,
Aspidiiim filix-mas, Ceratopteris or Adiantum. In those
species where considerable elongation of the lowest cell
occasionally takes place, it seems to be caused by deficiency
of light. The first rootlet is produced during the con-
tinuance of the transverse division of the terminal cell of
the young prothallium : it has the form of a cylindrical
process developed from a protrusion of the membrane of
the lowest, more rarely of the second lowest, cell of the
prothallium. The rootlet very soon after its appearance is
separated from the original cavity of its mother-cell by a
septum convex towards the interior (PL XXIV, figs. 1 — 3).
After about the fifth transverse division of the apical cell
of the young prothallium, this cell divides by a longitudinal
septum. The two apical cells afterwards divide frequently
by transverse septa, In the cells of the second degree
which are thus formed transverse septa are produced. The
formation of these septa is however usually suppressed in
the two or three first-formed lowermost pairs of cells and
often also in one of the two next equal-aged cells (PI. XXIV,
fig. 2). Thus the prothallium begins to be converted into
a cellular surface. At the same time the direction of its
growth is turned more and more from the light, so that it
soon assumes a position parallel to the surface of the
ground : when the light is powerful it adheres closely to
the earth.*

The apical cells often divide also by longitudinal septa,
which diverge slightly from the longitudinal axis of the
prothallium, and which, like all septa which are produced
during the early growth of the organ, are perpendicular to
its surface. The prothallium has now four apical cells, of
which the two outer ones grow more rapidly in length than
the median ones, and immediately divide repeatedly by

* The turning away of the prothallium from the light, by which the fore
edge of each prothaliium is continually diverted from the source of light, was
first observed by Wigand (-'Beitrage zur Botauik,' 1854, p. 35). His explana-
tion however is altogether erroneous ; he assumes that the upper surface of the
prothallium was drawn from the light. If this were so the prothallium must
turn itself to the light.

184 HOFMEISTER, ON

septa rutting those which diverge from the longitudinal axis
of the organ at an angle of about 45° (PI. XXIV, fig. 3).
By this means the foundation is laid for the two-lobed form
of the prothallium. The cells of the edge of the wings of
the fore end of the prothallium then divide very frequently
by septa parallel to the chord of the arc of their circum-
ference. After a series of such divisions there are produced
in the marginal cells, longitudinal septa at right angles to
the latest formed transverse septa. This cell-multiplication,
by which both lobes of the prothallium are rapidly and
remarkably enlarged, is least active on the outside of the
lobes, where it soon ceases. The cessation progresses from
the hinder part of the protallium to the apex of each of the
side lobes. On the other hand those cells of the two lobes
which are directed towards the deep indentation of the
fore edge, continue to multiply for a longer period. The
multiplication, however, is most active in the two cells
which occupy the base of the notch between the two wings
of the prothallium, which notch is constantly increasing in
depth. These cells divide continually and repeatedly by
means of transverse septa at right angles to the longitudinal
axis of the prothallium, alternating with divisions by means
of longitudinal septa which converge slightly to the longi-
tudinal axis. Those of the new cells thus formed which are
farthest from the middle point of the indentation begin
immediately to diverge in their growth from the longitu-
dinal axis of the prothallium to the extent of about 65°.
By this means the new cells thus produced drive the cells
adjoining them on the outside upwards and outwards.
During their change of position the growth of these cells
diverges more and more from the longitudinal axis of the
prothallium, ultimately to the extent of 90°. Those
daughter-cells which are separated from the cells in the
lowest portion of the indentation push themselves upwards
laterally by the side of their mother-cells, by means of an
innate power of growth. Whilst they push the adjoining
older cells outwards, thsy take part in the formation' of the
two side wings of the prothallium, which consequently in-
crease continually in size and in the number of theircells, not-
withstanding the progressive cessation of the multiplication

THE HIGHER CRYPTOGAMIA. 185

of the cells of their outer edge (PI. XXIV, fig. G). The
apical cell for the time being of the wing of the prothallium,

is continually pushed downwards and outwards and re-
placed by a younger one. The growth of the youngest
cells in the direction diverging from the longitudinal axis
of the side wings is frequently more active at their inner
than at their outer end. AVhere this phenomenon is very
strongly manifested it leads to such a remarkable develop-
ment of the breadth of the two wings of the prothallium
that the one overlaps the other. This circumstance how-
ever occurs, for the most part at least, only in prothallia of
exuberant growth ; it does not take place until the termina-
tion of the normal growth of the prothallium.

Individual cells of the under side of the prothallium pro-
trude outwardly in a hemispherical form. In very young
prothallia, or in thin shoots of old exuberant prothallia, the
same thing occurs in the marginal cells (PI. XXIV, fig. 4).
The development of these cellular excrescences usually
commences at the hinder part of the prothallium, proceed-
ing from thence towards the front part, but without any
very great regularity. As a rule one excrescence only is
developed on one cell of the prothallium. In the median
line of the latter, one of these excrescences is produced from
almost every cell ; towards the sides their number dimin-
ishes, and at the edges of the wings of the prothallia the
formation is entirely suppressed. Their expansion coincides
with that of the radicular appendages. The protruding
portion of the free outer surface of the cell is soon separated
from the primary cell-cavity by a transverse septum. This
transverse division is often repeated a second time, more
rarely several times, so that the hemispherical terminal cell
of the excrescence is supported by one, or by several, discoid
shortly cylindrical cells. The nature of their contents
differs little at first from that of the vegetative cells of the
prothallium. The walls are covered by a layer of chloro-
phyll having somewhat smaller granules than that of the
neighbouring cells ; their supply of protoplasm is somewhat
larger. Prom this period the highly refractive protoplasm
of the young antheridium accumulates to such an extent,
that the arrangement of its component cells is very difficult

186 HOFMEISTER, ON

to recognise. There can however be no doubt that after
some time the antheridmm is composed of a cylindrical or
angular, almost cubical, central cell of large size, very rich
in granular protoplasm, supported by one cylindrical or two
semi-cylindrical cells, covered by a cell having the form of
a segment of a sphere, and surrounded laterally by a girdle,
which in most cases looks at first sight like a simple
annular cell, or two such cells standing one over the other,
but which, after more careful examination, and especially
after treatment with a saccharine solution and iodine, may
often be seen to be composed of several cells, from two to
four in number, lying in one plane.

Those states of the antheridia which, judging from their
size and their position on the prothallium, are intermediate
between the condition just mentioned and the unicellular
condition, may be distinctly recognised by the sharply de-
fined, circular boundary line of the apical cell; and, less
distinctly, by the appearance of the central cell which is rich
in protoplasm. In some young antheridia the best object-
glasses especially when combined with the use of a solution
of sugar and iodine exhibit the lines of contact of the cell-
walls with the outer surface of the antheridia. These lines
run obliquely downwards, usually in a left-handed spiral
which describes about a sixth part of a circumference (PI.
XXIV, fig. 9). The analogy to be derived from the pro-
cess of development of the antheridia of the Muscineae ren-
ders it probable that the large central cell is formed by the
production of an excentrical, inclined, longitudinal septum
in the young antheridmm, followed by the production of
another excentrical septum cutting the latter at right
angles, and the subsequent formation of a longitudinal
septum cutting both the above at an angle of 45°, such
formation taking place after the apical cell of the antheri-
dmm has been isolated by a strongly inclined almost hori-
zontal septum cutting the primary longitudinal septum.
Where the central cell is surrounded by two zones of en-
veloping cells it is manifest that the two zones originate in
the transverse division of the primary single zone.

The structure of the prothallia and antheridia of all the
Polypodiacese which have been yet examined is identical in

THE HIGHER CRYPTOGAMIA. 187

all essential points. The only specific differences are, that
in certain species (such as Aspidium filix-mas, and several
species of Adiantum) certain marginal cells of the pro-
thallium grow into papillae, which in Aspidium are thin and
cylindrical with a clavate end, and in Adiantum are very large
and flask-shaped, whilst in the prothallia of other ferns the
margin is destitute of such protuberances, as is the case
in Pteris aquilina and serrulata. The only known instance
of variation is afforded by Ceratopteris thalictroides. When
the large spores of this species germinate, and the exospo-
rium bursts, it is seen that the portion of the prothallium
which is enclosed within the lobes of the exosporium, is a
multicellular roundish body. The conclusion from this fact
is that the inner cell of the spore is divided into several
daughter-cells before the bursting of the exosporium. The
prothallium moreover does not develope two lateral lobes
with a deep indentation between them, having the focus of
continuous cell-multiplication, at its base, but the point of
most active cell-multiplication is situated sideways on the
prothallium (PL XXIV, fig. 16). One wing only of its
fore edge is developed. The rudimentary cells of the
antheridia are for the most part marginal cells of the pro-
thallium somewhat deeply buried between the vegetative
cells of the margin. The process of cell- division in them
coincides with that which is supposed to exist in most of
the Polypodiaceas (PL XXIV, figs. 17—19).*

* Wigand states that the mother-cells of spermatozoa, and even motile
spermatozoa themselves, are sometimes found in the chlorophyll-bearing vege-
tative cells of the prothallium. This statement has not been confirmed by any
other observer. Wigand has probably seeu appearances which I have myself
met with, though on rare occasions. I have found in mauy of the vegetative
cells of old, abnormally developed, prothallia, globular or elongated, sharply
defined masses of a thick mucilaginous substance which for the most part hung
together in arborescent ramifications, but were to some extent detached, and
formed entirely free globular bodies. The diameter of these bodies is but little
(about a third) greater than that of the mother-cells of the spermatozoa. They
wei;e present in individual cells sometimes in greater sometimes in less num-
bers. The arrangement of the "chlorophyll of the cells in which they were
enclosed was not materially disturbed although the colour of the chlorophyll
was slightly faded. Some of the arborescent groups were drawn out at one
end into a thin thread-like cell which had quite the appearance of a fungoid
filament, and which was attached at its extremity to the free outer wall of the
cell of the prothallium. In other cells of the same prothallium the chlorophyll
had disappeared and they were filled with empty cells having a firm membrane
and looking like the mother-cells of zoospores. These structures are certainly

188 HOFMEISTER, ON

The cells of the antheridia, which surround the central
cell, do not multiply any farther. The latter, however,
after a considerable increase of its circumference, is trans-
formed by a series of divisions into a globular group of
cubical cells (PL XXIV, figs. 10, 11). By the growth of
this cellular mass the cells of the covering layer are ex-
tended more and more into a tabular form, sometimes to
such an extent, that their cavities are entirely obliterated.
During the multiplication of the central cell their fluid
contents have become as clear as water.

In each of the small tesselated cells within the antheri-
dium there is produced a flat spirally twisted spermatozoon
in the interior of a lenticular or globular vesicle, tlie latter
being apparently the primary nucleus of the small cell.
The turns of the spiral are but few in number.

As the antheridium approaches maturity the walls of
the small internal cells are dissolved and the vesicles en-
closing the spermatozoa then lie free, enveloped in a granu-
lar mucilage, and surrounded by the compressed covering-
cells. If the antheridium is now exposed to moisture,
its contents swell, the flatly compressed cell of the apex
bursts in the middle in a stellate manner, and the vesicles
enclosing the spermatozoon escape through the fissures.
If the spermatozoa are fully- formed and ripe, the vesicles
when lying in water, exhibit a rotatory motion shortly after
their escape from the antheridium. I have often observed
that at the commencement of this motion, one of the ends
of the spermatozoon (usually the fore-end, which is the
thicker one and bears the cilia), protrudes from a fissure in
the vesicle. Suddenly the vesicle bursts by a wide open-
ing, the spermatozoon becomes free, and shoots out from it
in very rapid motion.

The expanded fore-end of the spermatozoa, as has been
mentioned, is compressed laterally to a considerable ex-
tent ; the outer side of its spiral coils bears numerous deli-
cate cilia, which vibrate actively during its motion (PI.
XXIV, figs. 13, 15). At the opposite end the sperma-
tozoon gradually fines off into a very long hair-like termina-

aiways foreign to the prothallium and are probably states of development of an
entophytal fungus.

THE HIGHER CRYPTOGAMIA. 189

tion. The latter often retains its original spiral form, and
remains attaelied to the interior of the vesicle within which
the spermatozoon originated (PI. XXIV, fig. 14"-*). The
forward motion of the spermatozoon is always accompanied
by a rapid rotation round the axis of the spiral, and follows
the direction of this spiral, which is sometimes a right-
handed, sometimes a left-handed one.*

When the prothallinm has become two-lobed, and has a
deep indentation on its fore-edge, the cells of that portion
of it which lies immediately behind the indentation, divide
by means of septa parallel to the surface of the prothal-
linm. This division is repeated two or three times, always
in the lower one of the newly-formed cells. By this
means a flat cushion of cellular tissue is formed on the
under side of the prothallinm. On its hinder part, new
antheridia continue to be formed for a considerable time.
The archegonia are produced at the fore -part adjoining the
indentation. t

The mother-cell of an archcgoniimi is distinguished from
the adjoining cells by an abundance of finely granular
mucilage, and by the presence of a larger less flattened
nucleus. The adjoining cells just mentioned are rich in
chlorophyll : their contents are clear like water, and they
have a small lenticular nucleus adherent to the cell- wall.

* The statements of authors with regard to the form of the spermatozoa of
Ferns, their number, their nature, and the mode of attachment of their cilia are
in some respects very contradictory. Their discoverer, Niigcli, makes no
mention of cilia. Lesczyc-Sumiuski in his account of the development of Terns
(Berlin, ISIS) speaks of a few large cilia as attached to the clavatc fore end
of the spermatozoon of Pteris serrulala. This is an error, as the spermatozoa of
the latter species are similar to those of Asplcnium. Schacht (' Linnsea,5 Td.
xxii) considered the vesicle in which the spermatozoon is produced, and which is
often dragged along by the whip-shaped end of the latter, to be an essential
portion of it. This accounts for the difference between his observations and
those of other botanists. He considered the vesicle to be the fore end of the
spermatozoon and that the hinder part preceded the narrower ciliated coils
when in motion. Thurct's statements ('Ann. desSc. Nat,' iii ser., vol. 11)
agree with mine except that he does not mention the tail of the spermatozoon.

f In order to justify the application to the organs of Terns, of an expression
hitherto only used when speaking of the female organs of mosses, I must refer
to a subsequent part of this work ; where I endeavour to show that the fruit
(capsule and fruit stalk) of a moss answers to that which in ferns (taken in the
most extended sense) is simply called the plant ; and that the prothallium of
the fern is equivalent to the moss-stem, bearing antheridia and archegonia,
which is often much branched.

190 HOFMEISTER, ON

The hinder end of the spermatozoon is frequently drawn
out into a narrow prolongation, but this is not a constant
character. It arises probably from the fact that during
the parting asunder of the spermatozoon and its mother-cell,
the plastic substance of the spermatozoon remains attached
to the membrane of the latter cell, and is mechani-
cally drawn out into a thin filament, which eventually
breaks off.

The first division of the primary cell of an archegonium
can only be seen by means of careful transverse sections of
the prothallium made perpendicularly to its surface. The
cell divides into an inner and an outer daughter-cell by
means of a septum parallel to the free outer surface. The
former becomes the central cell of the archegonium — the
embryo-sac. At a later period it is the place of formation
of the embryo. The neck of the archegonium is produced
by the multiplication of the outer cell (PI. XXV, figs. 1,2).
This cell protrudes outwardly, and is divided into two
daughter-cells by a septum strongly inclined to the surface
of the prothallium, and often almost perpendicular to it.
This septum is sometimes at right angles to a plane passing
through the longitudinal axis of the prothallium, sometimes
it forms an acute angle with that plane, and sometimes it
is parallel to it. One of these positions is as frequent as
the others. The larger of the two daughter-cells is divided
anew by a septum super-imposed upon the latter septum, and
inclined in an opposite direction. The two-surfaced wedge-
shaped apical cell then divides from four to ten times by
means of septa inclined in different directions (PL XXV,
fig. 2). With this process the longitudinal growth of the
organ terminates. Each of the cells of the second degree —
which cells originate in the division of the apical cell by a
septum parallel to one of the lateral surfaces — divides im-
mediately after its production, by means of a longitudinal
septum radiating from the axis of the archegonium. The
neck of the archegonium consequently consists of four
parallel longitudinal rows of cells. Each of the cells con-
tains a lenticular nucleus, lying close to the cell-wall, and
from which strings of granular protoplasm radiate. Gran-
ules of a firm consistence are dispersed throughout the

THE HIGHER CRYPTOGAMIA. 191

protoplasmic covering of the cell-wall. These granules are
usually very few in number ; sometimes however they are
more abundant, and they are not unfrequently furnished
with a thin coating of chlorophyll.

The necks of the archegonia when perfect frequently
exhibit a central string of cells in their longitudinal axis
(PL XXV, figs. 3, 5, 6). The position of the cells of this
fifth longitudinal row relatively to those of the four sur-
rounding rows, leads to the conclusion that the axile row
of cells is formed by the division of the cells of one of the
primary longitudinal rows into three-sided outer and four-
sided inner cells by means of septa parallel to the chord of
the arc of the free outer surface ; a process analogous to the
development of the axile string >of cells in the neck of the
archegonia of liverworts and mosses. This formation of
axile cells frequently does not extend throughout the whole
length of the organ. It is sometimes suppressed in the
cells immediately adjoining the embryo-sac (PL XXV, fig. 5).
More rarely it occurs only in the latter cells, in which case
the upper part of the neck of the archegonia consists of
four, and its lower part of five rows of cells. Immediately
after the formation of the axile string, the contents of the
cells are found to be of a grumous nature, and the trans-
verse septa which separate the individual cells are soft and
gelatinous. When treated with a solution of glycerine, or
with any substance which abstracts water, the cells become
contracted, and form granular mucilaginous matter, some-
times in separate spherical lumps, sometimes in the shape
of a single vermiform body (PL XXV, fig. 8). I attribute
the formation of the similar masses which occur in the
canals of the necks of archegonia which are approaching
maturity, to a similar transformation of the axile string
during the further normal development of the archegonia
(PL XXV, fig. 11).

Quite as often however, or even oftener, the formation
of an axile row of cells in the neck of the archegonium is
suppressed. Both forms of archegonia occur upon pro-
thallia of the same species, and even upon one and the same
prothallium. The one form is as common as the other in
Pteris semdata and Ceratopteris thcdictroides. In Aspi-

192 HOl'MEISTER, ON

chum filias-mas and Gymriogramma ccdomelanos the first-
mentioned form is more frequent. This form answers to the
structure of the archegonia in liverworts and mosses, the
other corresponds with that of the archegonia of the
Equisetacese, Rhizocarpese, and Lycopodiaceas. Ferns con-
stitute the intermediate link between these groups, so far
as regards the organization of the female reproductive
apparatus.

During the longitudinal development of the neck of the
archegonium it bends backwards from the indentation of
the fore edge of the prothallium. The amount of curva-
ture varies slightly in the archegonia of the same pro-
thallium. The archegonia of prothallia which bear those
organs on both sides are bent in the same direction, those
of the upper surface being usually more curved than those
of the lower surface. The curvature is very considerable
in the necks of the archegonia of those prothallia which
are not close to the earth, but which (in consequence of
their growing in masses) have become diverted obliquely
upwards. Thus it would seem that the curvature of the
necks of arche°;onia affords another instance of negative
heliotropismus, i. e., of the turning away of an organ from
the rays of light.

The number of archegonia is far less than that of the
antheridia. On normally developed prothallia which con-
tain an embryonal rudiment, there are seldom more than
eight. The development of the archegonia commences
close behind the indentation of the fore edge of the pro-
thallium, and progresses from thence both forwards and
sideways during the continuance of the growth of the
prothallium.

In some prothallia, when growing under a sufficient
exposure to light, the rudimentary cells of the archegonia
are always on the under surface of the prothallium. Pro-
thallia however of the most different species, when growing-
erect in closely packed tufts, or in places where few rays
of light penetrate, develope archegonia on both surfaces.
On the upper surface, which is usually distinguishable by
the paucity or absence of rootlets, the archegonia are
usually mixed with antheridia. It is evident that shade is

THE HIGHER CRYPTOGAMIA. 193

favorable to the production of sexual organs as well as of
roots.

In Ceratopteris thalictroides, the antheridia of which
are abnormal in position and structure, prothallia occur
having numerous cushion-like masses of tissue in which
archegonia are produced, each one of such cushions being
situated behind one of the numerous indentations of the
edge of the prothallium.

At an early period, even before the complete formation
of the neck, a secondary free nucleus appears in the
upper part of the central cell of the archegonium. The
large primary nucleus of the central cell is still present.
The secondary nucleus is soon seen to be surrounded by
a free spherical cell, in close proximity with the internal
surface of the apex of the central cell (PI. XXV, figs.
5 — 9). This is the germinal vesicle. When it first
appears its diameter is only about one sixth of that of the
central cell, but, even before the bursting of the apex of the
archegonium, it grows, to almost one half the size of its
mother-cell. For some time after its appearance the
primary nucleus of the central cell remains unchanged
(PL XXV, figs. 3, 5, 8) : at a later period it disappears ;
this takes place before the opening of the apex of the neck
of the archegonium (PI. XXV, figs. 4, 7, 11).

The cells of the inner tissue of the prothallium which
arc adjacent to the central cell of the archegonium, di-
vide repeatedly by septa at right angles to the bounding
surfaces, and by this means are converted into a kind of
epithelial layer, consisting of narrow cells containing a
quantity of finely granular protoplasm (PL XXV, figs. 3,
5, 11). The period of the commencement, and the in-
tensity of this multiplication, are very different in indivi-
dual instances. (Compare PL XXV, fig. 3, with PL XXV,

figs. 4, 7.) .

During the formation of the germinal vesicle a wide
canal leading to the embryo-sac is formed in the longi-
tudinal axis of the neck of the archegonium. The apex
of the neck of the archegonium remains firmly closed
during the development of this canal. In most cases
during the progress of this development, the cells of the

194 HOIMEISTER, ON

arch of the apex of the archegonium multiply by division
which takes place by means of septa at right angles to the
outer surfaces. This process is especially remarkable in
Gymnogramma calomelanos (PI. XXV, fig. 7). Where the
neck of the archegonium consists of only four longitudinal
rows of cells the axile canal is manifestly formed by the
parting asunder of the angles of contact of the latter cells.
The membranes of the cells grow in the direction of tan-
gents to the cylindrical organ : thus an intercellular space
originates between them, which is often of considerable
width. The process commences underneath the arch of the
apex of the archegonium and proceeds from thence to its
base (PL XXV, fig. 4). When the neck of the archegonium
is traversed by an axile string of cells the canal can only be
produced by the dissolution of the transverse septa of these
cells. In this case also the dissolution is preceded by an
increase in growth of the peripheral cells in a tangential
direction, which is especially remarkable at the apex of the
neck of the archegonium, so that the axile string of cells
assumes a clavate form (PI. XXV, figs. 5, 7).

Within the canal of the neck of the archegonium, whilst
the latter is still closed at the apex, there is sometimes (but
by no means always) to be found an elongated vermiform
body, of a finely granular, tough, gelatinous consistence,
club-shaped at the upper, and tapering towards the lower
end. At other times there may be seen several similar
bodies within the canal, of which the uppermost are
usually elongated, and the lower ones spherical. The re-
verse is however sometimes the case, the lower bodies being
sometimes longer than the upper ones (PL XXV, figs. 7,
11). These bodies are very probably nothing more than
the altered contents of the cells of the axile string of the
neck of the archegonium, which upon the dissolution of the
transverse septa run together more or less completely into
one mass. The elongated clavate form of the upper of these
bodies (a form which is of frequent occurrence when
several of such bodies are present) probably results from the
fact that in this case also the formation of the canal of the
neck, the dissolution of the transverse septa of the axile
row of cells, and consequently also the flowing together of

THE HIGHER CRYPTOGAMIA. 195

the contents of these cells, proceed from above downwards ;
the process taking place rapidly at first, and afterwards
more slowly.

After the formation of the canal of the neck, and whilst
the apex of the archegoninm is still closed, the walls of the
cells of the peripheral layer become arched inwards to a
considerable extent, and protrude into the canal : a mani-
fest proof that these cells, being in a state of active expan-
sion, exert a great pressure upon, and displace the fluid
contents of the canal. Ultimately the cells of the apex
part asunder, by which means a portion of the mucilaginous
fluid contained in the canal usually escapes through the
opening. By this means individual cells are not unfre-
quently detached and thrust off (PL XXV, fig. 12). The
canal is now open externally, and exhibits an uninterrupted
communication from without inwards, up to the central
cell of the archegonium.

The membrane of the arch of the apex of the latter has
in the mean time become softened. A gentle pressure upon
the covering glass not only forces the mucilage of the canal
out of the mouth of the latter, but a portion also of the
contents of the embryo-sac is gradually driven into, and
through the canal. The motion however is not so sudden
as in the case where the contents of a cell escape through a
fissure produced by the bursting under pressure of an elas-
tic membrane. In one case I observed that one of the
bodies in the canal had made its way into the central cell ;
a circumstance which proves clearly the exposed nature of
the embryo-sac (PI. XXV, fig. II). The membrane of the
germinal vesicle on the other hand, even before the burst-
ing of the archegonium, is somewhat firmer. It is clearly
seen, when an embryo-sac and the germinal vesicle within
it are injured in making a section, that the membrane
exhibits folds (PI. XXV, tig. 9).

Most archegonia are not developed any further. The
cell-walls which adjoin the canal, as well as the large cell
at the base of the archegonium, assume the purplish-brown
colour, which is peculiar to the fading cell-membranes of
almost all the higher cryptogams. This is the fate not

196 HOFMEISTEll, UN

only of all except one- of the archegonia of the same prothal-
lium, but by far the greater number of prothallia are en-
tirely abortive, and produce no young plant. It is not too
much to say that hardly one prothallium in ten produces
a frond-bearing plant. Prothallia which are devoid of
embryos, do not, however, by any means die ; when they
are not deprived of the conditions essential to their vitality,
that is to say, moderate warmth, subdued light, and
abundant moisture, they continue to develope themselves
for several months. In the simplest case the side lobes of
the prothalliuiii increase very considerably in size ; they
overlap one another to a great extent in front of the inden-
tation of the fore edge. The prothallium when growing
exuberantly becomes circular ; it attains a diameter which
is from four to six times larger than that of the prothallia
of the same species which have produced young plants.
This is the regular rule in abortive prothallia of Gymnog-
ramma chrysophylla and others. The cushion of the uneler-
surface grows at the same time in thickness and in length.
The latter growth is produced by repeated division of the
cells which adjoin the bottom of the slit of the fore edge, and
which division takes place by means of septa at right angles
to the upper surface of the prothalliuiii. At the same
time a number (often a very great number) of archegonia
are usually produced upon the prominent cushion of lieshy
cellular tissue on the under side of the prothallium. These
archegonia, with the rarest exceptions, are all abortive,
probably in consequence of the fact that no more new
antheridia are produced upon the hinder, oldest portions, of
the same prothallium . The earliest of these archegonia
have the same form as those which are produced contem-
poraneously with the latest antheridia. The later ones,
however, either develope a rudimentary neck only, or no
neck at all. The large central cell and the canal filled with
mucilage which leads to it appear to be sunk into the under
side of the prothallium (PI. XXVIII, fig. 2). The obser-

* With the rarest exceptions, such as the case of Ceratopteris thalidroides,
observed by Mercklin {' Beobachtungen au Prothallium der Farrnkr.' Peters-
burg, 1850) and Pleris aquilina and Aspidium filix-mas observed by myself.

THE HIGHER CRYPTOGAMIA. 197

vation of such archegonia, and (lie comparison of them with
those placed farther backwards and having perfect necks,
seems to have led Lesczyc-Smninski, and after him Merck-
lin, to the erroneous conclusion, that the archegonium in
its earliest youth was a short canal opening upon the under
side of the prothallium, and that the neck was formed by
repeated division, in a direction parallel to the surface of
the prothallium, of the cells surrounding the mouth of that
canal.

The abortive prothallia of Nothochlsena, Allosurus, and
Gymnogramma calomelanos often exhibit shoots. The ar-
rangement of the cells of the prothallium of ferns generally
resembles that of the leaf-like shoots of Pellia, Riccia, and
Marchantia. It might be supposed from this that a new
shoot would originate at the bottom of the notch of the
fore edo-e, and that new shoots again would arise in the
axils which the last-mentioned shoot would form with the
side wings of the fore edge. This, however, is rarely the
case (PI. XVIII, ng.li). Usually several of the cells of the
edge of the prothallium grow into adventitious shoots, which
generally have the shape of a large spatula. The activity
of the multiplication of their cells breadthwise is ex-
ceedingly various. Very slender adventitious shoots
witli unicellular bases often become detached from their
prothallia at an early period by the death and disso-
lution of the cells attached to them. They then represent
independent, very small prothallia (PI. XXIV, fig. 4), and
often bear very numerous antheridia.

The development of a very great number of antheridia
is an especial peculiarity which often occurs in the shoots
of the prothallia of ferns. They are either entirely barren,
or if antheridia are found, the latter are in great multitudes
and closely pressed together, there being often as many
as a hundred upon one shoot. I have never seen archegonia
upon one of these shoots ; they certainly have a tendency
to produce only male organs of fructification.

Old abortive prothallia of Gymnogramma chrysopliylla
often exhibit a very remarkable appearance in winter.
Near the hinder end several small oval knots of cellular tissue
are formed ; little knots varying from the size of a millet-
seed to that of a pea, and consisting of narrow cells filled

198 H0FME1STER, ON

with starch and oil-drops (PL XXVI, fig. 3p.) In the
earlier stages these knots are whitish or yellowish in colour ;
afterwards their outer side becomes brownish by the forma-
tion of from two to three layers of cork- cells. Perhaps
these wonderful organs are gemmae, destined to reproduce
the proth allium.

It may be considered as beyond question that the pene-
tration of a spermatozoon into the open canal of the neck of
the archegonium is necessary in order that the spherical
cell within the central cell may be further developed, so as
to become a frond-bearing plant. Under ordinary circum-
stances the spermatozoa have the means afforded them of
swimming to the opening of the archegonium. Whenever a
dew occurs, numerous drops of water are found on the
under side of the parenchymatal cushion of the prothal-
lium. The flat space between the prothallium and the
ground is often filled with water. Under such circum-
stances, as the ground becomes gradually drier, air-bubbles
are formed under the prothallium, and their presence is
shown by the silvery-green glimmer which is exhibited by
the tissue above them.

The spermatozoa enter the canal, pass through it, and
ultimately reach the interior of the central cell, piercing
through the softened membrane of the apex of the latter.
Here they move about for some time, sporting actively around
the germinal vesicle, which is in close proximity to the
inner wall of the central cell near the place of entry of the
spermatozoa,* Immediately after the arrival of sperma-
tozoa in the embryo-sac the interior of the mouth of the
canal is closed by the transverse expansion of its bounding

* I repeat here, with some additions, the course of observations upon which
the above statements are founded, an account of which I have already given in
the ' Reports of the Royal Scientific Society of Saxony.'

"When a quantity of fern-spores are sown, the germinating prothallia are
developed at very different periods. The earliest prothallia produce in the first
instance only antheridia, afterwards antheridia and archegonia together, and
when advanced in age, only archegonia. The earliest prothallia have already
attained the latter stage at the time when the later prothallia, the development
of which has been retarded by the shade afforded by the earlier ones, are
thickly covered with antheridia. If the plants are now kept for some days
rather dry, and then saturated with water, the result will be that numbers of
antheridia will emit spermatozoa, and numbers of archegonia will open contem-
poraneously. The water should not be poured over the plants, but the pot
should be placed in water nearly up to its margin, by which means capillary

THE HIGHER CRYPTOGAMIA. 199

cells. This process is the first visible effect of impregna-
tion ; in abortive archegonia the canal remains open. Tn
the latter the Avails of the canal throughout, and also those
of the central cell, assume a deep brown colour. In im-
pregnated archegonia this colour only extends downwards
over that part of the canal which is not closed. Immedi-
ately after the closing of the lower end of the canal, and
during the progress of active multiplication in the cells
adjoining the embryo-sac, the impregnated germinal vesicle
attains the size of the sac. Even before it arrives at this
stage two secondary nuclei usually appear in its interior in
the place of the primary one which has disappeared (PI.
XXVI, fig. 5). The first septum by which the germinal
vesicle is divided, is not however formed until the latter
has entirely filled the embryo-sac. This septum stands at
right angles to the longitudinal axis of the prothallium, and
almost perpendicular to its surface. It diverges from a
perpendicular erected upon that surface, downwards and
forwards towards the indentation of the prothallium {a, b
in PL XXVIII, figs. l\ 35; PL XXVII, figs. 6 ', 7 »).
Soon afterwards an oblique septum is formed in each of
the two cells into which the germinal vesicle is divided ;

attraction and condensation will yield abundance of moisture to the prothallia.
After one or two hours the surfaces of the larger prothallia, which are covered
with archegonia, are found almost covered with spermatozoa, partly in motion
and partly at rest. If a delicate longitudinal section through the parenchyma
of these prothallia- be examined immediately, with a magnifying power of from
200 to 300 diameters, spermatozoa are sometimes found in all the archegonia
along the whole length of the section. I thus found three spermatozoon in
active motion in the central cell of the archegonium of Aspiclium filix-mas. In
this case the motion ceased seven minutes after the commencement of the
observation, and was accompanied (probably caused) by the coagulation of the
albuminous matter of the cell-contents. In the same fern on two occasions, and
also in Gymnogramma calomelaiws and Pteris aquilina, I have seen a spermatozoon
in motion in the central cell of the archegonium ; and in the above-mentioned
species, and also in Asplenium septeririonale, and filix-femina, I have seen a
motionless body near the germinal vesicle (after the growth of the latter has
commenced) answering in form to a spermatozoon. Lastly, in Aspiclium filix-
mas and Pteris aquilina, I have often seen motile spermatozoa in the canal of
the opened archegonia, the motion of which spermatozoa ceased during the
continuance of my observation. I may add that these observations were very
numerous, and were undertaken with the view of following out the cell
development of the embryo. In a single prothallium, cultivated in the manner
stated above, and laid open longitudinally as I have mentioned, there will not be
found more than three, or at the most, four archegonia open at the apex ;
spermatozoa will probably be found in not more than one in thirty of such
archegonia, and they will often not be found at all.

200 HOFMEISTER, ON

the septum in the hinder cell is inclined downwards and
backwards, that in the front cell upwards and forwards.
The young embryo now consists of four cells, having the
form of segments of a sphere, which fall into a vertical
plane passing through the longitudinal axis of the pro-
thallium (PI. XXVIII, fig. 1). Pteris aquilina and Aspidium
filix-mass exhibit a specific difference in the angles of incli-
nation of the newly-formed septa. The upper angle which
the newly-formed septum in the front cell forms with the
older one (PI. XXVI, figs. 6 *, 7 *, b, c) is widely open in
Aspidium jUix-mas ; it is almost a right angle; the lower
angle of the septum in the hinder cell is very acute (PI.
XXVI, figs. 6 *, 7 *, a, d). In Pteris aquilina this state
of things is exactly reversed (PI. XXVIII, figs. 1 h, 3 h, a, d,
b, c). In connexion with this difference there exists also a
difference in the further development. In both species the
stem-bud and the first frond are formed out of one of the
four cells, viz., the lower one of the two front cells (PL
XXVIII, figs. 1, 3, a.c; PI. XXVI, figs. 6, 7, a.c), and
the first root is produced from another of those four
cells. But in Aspidium filise-mas the mother-cell of the
root (6,d PL XXVI, figs. 6, 7) lies opposite to that
of the stem ; in Pteris aquilina it lies at the side (a,d
PL XXVIII, figs. 1, 3). In Aspidium the primary
abortive axis of the embryo,* is developed almost ex-
clusively by continual divisions of that one of the four
cells which is most distant from the mouth of the archego-
nium. In Pteris the descendants of the two cells which
are furthest from the archegonium compose this organ,
which in that genus is much larger (PL XXVIII, fig" 3).
The fourth cell of the young embrvo which lies under the
mouth of the archegonium multiplies still further in Aspi-
dium, although only to a slight extent. Its derivative
cells do not form a detached portion of the germ-plant,
but go to form the cortical portion between the back of
the first frond and the first root (PL XXVI, fig. 7).

All the vascular cryptograms in which the germination

* The foot-like appendage by which the young fern is attached to the pro-
thallium. Only a few of the cells of the rudiment of the root take part in the
formation of this "foot" (PI. XXVI, fig. 7).

THE HIGHER CRYPTOGAMIA. 201

lias been observed exhibit the same arrangement of the
first four cells of the embryo. This arrangement exists in
the Rhizocarpeas, the Equisetacese, and in Isoetes ; and the
position of the first cells of the rudiment of the germ-plant
at the lower end of the suspensor of Selaginella, is the
same. In these cases the primary leafless axis is formed
principally by the multiplication of the lowest of the four
cells ; of that one namely which is turned away from the.
mouth of the archegonium. One of the side cells produces
the primary indefinite axis of the plant. A third cell forms
the first root, if the embryo produces such an organ. Sal-
vinia is well known to be generally rootless ; Selaginella
does not send out the first root until after the first bifurca-
tion of the stem. In this prevailing fact there is such a
marked difference between the vascular cryptograms and
monocotyledons, that the remarkable similarity between
the germ-plants of the Naiadeae and the grasses, and those
of the vascular cryptograms (especially such of the latter as
have a prothallium devoid of chlorophyll) upon which
similarity I once attempted to ground a comparison of the
organs of the two families, appears to be an unessential
external resemblance.

The multiplication of the primary cell of the lateral
principal shoot considerably exceeds that of the mother-
cell of the primary axis. The same thing prevails
although in a less degree in the primary cell of the
first root. Both divide by means of septa inclined in
different directions, and, it would seem, in a manner
similar to that in which in the more advanced plant,
the multiplication of the cells of the first degree takes
place. I recognised the triangular form, when seen from
above, of the apical cell of the principal shoot in Aspi-
diumfilias-mas, and the two edged form of the same cell,
when viewed in a similar manner, of Pterls aquilina,
after about three divisions had taken place in each of
them. Even after the first round of divisions the stem-
cell of the first degree ceases to multiply further : * a
proportionally more rapid sequence of divisions begins in

* See the explanation to PI. XXVIII, fig. 3 \ and PL XXVII, figs. 6», 7".

202 HOFMEISTER, ON

the cell of the second degree, contiguous to the mouth
of the archegonium, which has been cut off from the
stem-cell. This cell of the second degree is the primary
cell of the frond.

That moiety of the primary cell of the principal shoot
which adjoins the first cell of the primary abortive axis is
considered to be a cell of the first degree, the principal rea-
son for which is, that at a later period, and when the germ-
plant is more developed, the cell in question appears as
the apical cell of the stem. It would be a simpler mode of
settling the rank of the cells, if that cell were con-
sidered to be of the first degree, in which the successive
divisions take place, not only at the earliest period, but in the
primary direction*; and according to this method there
would be no doubt that the primary cell of the stem, consi-
dered in relation to that of the frond, must be looked upon
b as a cell of the second degree ; an opinion which might be
made use of in support of the theory of the origin of the
fern-stem from the amalgamation of the stalks of the
fronds.* As, however, there are but few plants which ex-
hibit so manifest a terminal bud (around and under which
the appendicular organs take their rise), as the ferns do
when they have attained some growth, it follows that here,
as in the similar instances of monocotyledonous embryos,
it is necessary in forming an opinion as to the rank of the
cells, to have regard to the condition of the plant at a
period subsequent to the formation of the cells in question.
In the two species immediately under consideration, the
cell-succession in the first frond agrees substantially with
that in the later ones, but at the same time it differs consi-
derably. The surface of the first frond is, however, in its
inception, parallel to that of the prothallium, as is the
case in all the Polypodiacese which have been hitherto ob-
served. The primary cell of the root divides in the first
instance by septa turned towards the neighbouring cells ; the
division takes place twice by means of opposite septa (concave

* Considerations of this nature may have led Nageli to deny that ferns have
leafy stems (' Zeitschrift fur wiss. Botanik,' Heft 3 and 4, p. 148) ; Han-
stem's notion of the fern-stem also rests upon this foundation ('LinuEea/
1848).

THE HIGHER CRYPTOGAMIA. 203

to one another in JPteris aquiima), so that the cell retains
its original two-edged form ; and three times by means of
flat septa diverging from one another at angles of 60°, so
that the cell assumes the shape of a three-sided pyramid
with an arched under surface (Pl.XXVl,fig. 6). In both cases
a septum is now formed parallel to the chord of the outer
arc (PL XXVIII, fig. 1 ; PL XXVI, fig. 7). The flat cell cut
off by this latter septum is the first rudiment of the root-
cap, whose outermost, hood-shaped, cellular layer is formed
by the multiplication of this cell. Henceforth the root-
cell of the first degree lies surrounded by cellular tissue.
Its further increase arises from repeated divisions occurring
in the same succession.

> Judging from its position, the first root of the young fern
is adventitious, differing in no respect from the later
adventitious roots of the full-grown plant. This view of
the nature of the first root of the vascular cryptogams in
general (a view which I expressed many years since*),
has lately been objected to by Wigand. His first objec-
tion (an unfounded one) rests principally upon a con-
jecture that the foot-shaped portion of the germ-plant, that
which I have called the primary axis, not only amalgamates
with the prothallium, but is probabh/ prolonged backwards
so as to form the root. Wigand adds, " I consider that
the enlargement of the lower part of the germ-plant is of a
different nature ; I look upon it as the undoubted rudi-
ment of the first main root; it does not break through
after the manner of an adventitious root." A few words
of explanation are requisite as to the distinction be-
tween main roots and adventitious roots in general.
Our conceptions of main roots rest entirely upon the
observation, that the portion of the embryo of dicotyle-
dons, which is situated beneath the cotyledons (and in
most instances that portion of the plant alone) is prolonged
downwards and becomes the root, and that in a normal
state no portion of the plant above the cotyledons sends
forth roots. Now, strictly speaking, the root by no means
commences close underneath the insertion of the cotyledons,
for between the latter point and the root there is to be
* Berliu 'Botanische Zeitung,' 1849, 797.

204 HOFMEISTER, ON

foimd the small embryo-stem which Irmisch calls the
hypocotyledonary axis, and which Clos calls the collet. The
place of origin of the root, i. e., the lower end of the embryo-
stem, is difficult to discover by direct observation, but may
safely be defined as the point at which in the lower end of
the very young embryo the cell-multiplication peculiar
to the root commences. Now, whether the young root of
the germinating plant has the appearance of an immediate
prolongation downwards of the embryo-stem (as is the case
with most dicotyledons, and with a few monocotyledons,
such as Juncus, Allium, and Paris) — or whether it (the
young root) breaks out from the interior of the lower end
of the embryo, as in the Palms and the Loranthacae — de-
pends simply upon the fact whether the place of origin, the
focus of cell-formation of the root, lies nearer to or further
from the lower end of the embryo. In both cases the
root is a main root. ' An adventitious root differs onlv in
the fact, that its longitudinal axis does not coincide with
the prolongation of that of the embryo, but forms with
the latter a considerable angles For instance, the Orchi-
dese, the Fluviales, and especially (as Irmisch has well
observed), the Grasses, have no radicle, but only adventi-
tious roots. The distance from the surface of the place of
origin of adventitious roots is variable, being less in some
plants than in others. In the former case the surface of
the adventitious roots passes gradually into the cortical
layer of that portion of the plant from which they spring,
as may be observed in the pea when germinating. In the
latter the adventitious roots pierce through the outer cel-
lular cortical layers, throwing back those layers in the form
of a ring round the place of egress of the roots. The
absence of these characteristic collars (Coleorhiza?), at the
base of the adventitious roots, is by no means unusual.*
Ferns with creeping stems almost always have them, and
those with upright stems not unfrequently. It is well
known that all ramifications of roots, both those from main
roots and those from adventitious roots, are formed from the
outer surface of vascular bundles, and must therefore, with-
out exception, break through the bark. The reason why

* See Irmiscli's observations on ' Neottia nidus avis.'

THE HIGHER CRYPTOGAMIA. 205

no Coleorhizse are usually visible here, is, that (as in the
case of axile superficial adventitious-root-formation) the
direction of the root-branch in its earliest stage, generally
follows the axis of the root. The bark of the latter is
pierced by the former during the young state of the cells
before they have attained their final thickness. The con-
tinual amalgamation of the contiguous cells of the root
and its branch obliterates all traces of the gradual perfo-
ration.

During the first divisions of the rudimentary cells of the
stem, frond, and root, the two others of the four primary
cells of the embryo multiply by the formation of oblique
longitudinal and transverse septa (PI. XXVIII, fig. 3 ;
PI, XXVI, fig. 6), so that the embryo assumes altogether a
spherical form. Only the rudiment of the first frond ap-
pears at an early period as an elongated point.

Prom the time when the outer limits of the rudimen-
tary cell of the root are fixed by the formation of the
first cell of the root-cap, the cells of the upper surface
of the primary axis, and also the neighbouring cells of
the growing root, enter into close combination with the
adjoining cells of the prothallium.* The result is a
complete amalgamation of the adjoining outer surfaces
of the cells, which cannot now be detached from one
another by mere mechanical means. Henceforth the
embryo which up to this point lay free in the cavity
of the enlarged central cell of the archegonium, ad-
heres firmly to the prothallium. The adjoining cells
of each remain tolerably even. The attachment of the
embryo is not the result of arrangements such as we
find in the analogous process of the ingrafting of the
fruit of a moss into the axis of the mother-plant ; nor is
there any elongation of the basal cell of the fruit rudi-
ment into a capillary tube, becoming curved where it
penetrates the stem, as is the case in many Jungermanniac ;
nor is there as in Anthoceros any development of pro-
cesses from the cells of the broad, slightly convex, under
surface of the young fruit. From the moment of the
commencement of the amalgamation, the cells of the

* Sec Mohl in 'Wagner's Handworterbuch dcr riiysiol.,' vol. iv, p. 279.

206 HOfMEISTEU, ON

embryo which attach themselves to the prothallium divide
by the repeated formation of transverse septa into groups
of almost tabular cells. By this means the way is pre-
pared for the subsequent not inconsiderable longitudinal
extension of the primary axis of the embryo which is the
result of cell- expansion.

The action of concentrated sulphuric acid soon loosens
the connexion between the prothallium and the embryo.
If the latter is detached the outer surface of its primary
axis appears to be surrounded by a gelatinous envelope
with radial markings : this is the loosened adhesive mat-
ter by which the embryo and the prothallium were united.
The outlines of the cells of the latter are most clearly
marked upon it by a net-work of narrow band-like protu-
berances.

The growth of the embryo is accompanied by an active
multiplication of the cells of the prothallium adjoining the
impregnated archegonium. This multiplication, which is
not confined to the cells immediately adjoining the central
cell of the archeoonium, gives rise to the formation of a con-
siderable cellular protuberance, attached to the under side
of the prothallium, and which encloses the embryo. The
circumference of this excrescence is usually very consider-
able in Pteris aquilhia. The increase in growth of this
cellular tissue usually keeps pace so completely with that
of the embryo, that the expanding cavity is always exactly
filled up. The multiplication of the neighbouring cells of
the prothallium is not however caused by the pressure of
the growing embryo upon the side walls of the central cell
of the archegonium : this is manifest from the fact of the
occurrence of exceptional cases of imperfect growth of the
embryo, as has been observed, not only in many vascular
cryptogams, but even in mosses.* The embryo, probably
in consequence of imperfect impregnation, only occupies a
small portion of the enlarged cavity of the central cell of the
archegonium, as has been observed by comparing two im-
pregnated archegonia of the same prothallium in Pteris
aquilina and in Aspidium filix-mas (PI. XXVIII, fig. 2) ;

* By Got.tsclic in Calj/pot/eia Tric/io/iiaues, 'X. A. A. L. C.,' and by myself
in Frullania dilatata and Targionia hypophi/lla. ' Vergl. Unters,5 p. 41.

THE HIGHER CRYPTOGAMIA. 207

the same thing also has been noticed in Salvinia natans
and Pilularia globulifera.

The active longitudinal growth of the first frond and of the
first root of the young fern produces a constantly increas-
ing expansion of the surrounding tissue of the prothallium,
until the latter is ultimately unable to keep pace with the
increase in size of the young plant. The layer of tissue
surrounding the latter underneath, is ruptured transversely,
usually somewhat in front of the neck of the impregnated
archegonium. The frond immediately curves upwards, and
appears between the two flaps of the prothallium. Before
this period it has formed the rudiments of its lamina, which
in all ferns are much less divided in the young, than in the
full-grown plant. The first fronds of Potypodium valgare,
for instance, are not unfrequently undivided and lancet-
shaped ; more often however they are divided at the apex
into two portions of very unequal size. Contemporaneously
with the appearance of the first frond, the first root also
pierces downwards through the tissue of the prothallium.
Immediately after it makes its appearance it turns down-
wards into the ground.*

If the second frond of the germ-plant is developed
very soon after the first, the surrounding cellular tissue of the
prothallium in the neighbourhood of, or above the point of
egress of the first frond, is pushed outwards and forwards, and
is ultimately broken through. Before the frond makes its
appearance out of this covering, the latter resembles a coni-
cal wart protruding into the indentation of the fore edge of
the prothallium : it is the body which Wigand (' Bot. Zeit.'
1849, p. 121) has described as the prolongation of the
midrib of the prothallium.

* Yon Mercklin asserts (' Beobacht. am Prothallium der Parrnkr.' Peters-
burg, 1850) that soou after the appearance of the embryo in the interior of the
prothallium, a dark stripe becomes visible, passing from the base into the mass
of the prothallium, and expanding itself there. It contains a bundle of shortly-
jointed, striped vessels, the pointed ends of which reach to the neighbourhood
of the archegonia. The older the prothallium the more numerous are these
vessels, which, in their configuration, answer exactly to those of the large
vascular bundles of the first frond, and appear never to be wanting. I
find the prothallia of all the ferns which I have examined to be always com-
posed of homogeneous parenchyma, and to be devoid of vessels. I have not
the least notion what Von Mercklin's supposed striped vessels can be.

208 H0FME1STER, ON

Development of the vegetative organs. — -The similarity in
the development of the different species of ferns does not
extend beyond the formation of the rudiments of the first
frond and of the first root.

So far as regards the mode of development of the vege-
tative organs, the two commonest ferns of Germany re-
present the terminal points of the long series of multi-
farious forms of the most extensive family of the vascular
cryptogams. Pteris aquilina affords one of the most per-
fect examples of a fern with a creeping stem, having the
fronds arranged in two lines, and with a most decided
tendency to bifurcation of the terminal bud. The greater
number of the ferns inhabiting the forests of the torrid
zone comport themselves like Pteris aquilina. Aspidium
flix-mas, on the other hand, forms a stem tending up-
wards, and agrees essentially in its habit, in the arrange-
ment of its fronds, and in the division of its vascular
bundles, with the tree-ferns of the tropics. The follow-
ing observations will treat of the history of the develop-
ment of the two ferns just mentioned, and we will pro-
ceed first with Pteris aquilina.

Pteris Aquilina, L. — The surfaces of the septa formed in
the cell of the first degree in the first frond of Pteris aquilina
are turned towards the apex of the stem.* A plane passing
through the longitudinal axis of the stem and of the frond,
is at right angles to the lateral surfaces of the wedge-shaped
apical cells of both organs (PI. XVIII, fig. 6). Even at a
very early period, before the enveloping cellular layers of
the prothallium are ruptured by the longitudinal growth of
the first frond, septa are formed in the apical cell of the
frond on the right and left of its median line. These septa
are at right angles to the fore and hind walls, and they change

(DO 7 J O

the form of the cell, which has hitherto been wedge-shaped
like a segment of an ellipsoid, into a three-sided prism with
the edge turned downwards and having its hinder surface

* This is the case also with all the subsequent fronds not only of Pteris
aquilina but also of other species of the same genus ; as well as with the fronds
of such ferns as Pteris scrrulata, which have a triple frond-arrangement, and
where the apical cell of the terminal bud has the form of a three-sided inverted
pyramid. In the Polypodiums and Aspidiums the circumstances are widely
different.

THE HIGHER CRYPTOGAMIA. 209

arched. The longitudinal growth of the frond is also for-
warded by the production of septa which are parallel to the
fore and hind walls of the cell of the first degree, and are
turned towards the surfaces of the frond. From time to time,
however, the apical cell divides anew by longitudinal septa
at right angles to those just mentioned, and the end of the
young frond is by this means widened. Thenceforward
both forms of division continue to take place in the marginal
cells of the frond which adjoin the apical cell ; but the
activity of division diminishes in a lateral direction, and
terminates far above the place of insertion of the frond.
That portion of the frond which is situated above the point
at which the multiplication of the marginal cells terminates,
becomes the blade of the frond, and the portion below that
point becomes the stem of the frond. The cell-succession
of the leafy portion of the frond therefore much resembles
that of the flat stem of the Marchantieae and Riccieae ; but
there is invariably one cell only of the first degree ; not
two.

The formation of the pinnae of the frond in the species of
Pteris, as in the rest of the Polypodiaceae, is the result of a
true bifurcation of the apical punctum vegetationis. This
formation commences with the division of the apical cell by
a septum coinciding with the median line of the frond, and
perpendicular to its surfaces. Each daughter-cell is divided
by a septum almost parallel to the longitudinal axis of the
frond (PI. XXIX, fig. 3). This latter division occurs either
immediately, or after the previous formation of septa which
are inclined to the surfaces of the frond, and contribute to
its longitudinal growth. The three-sided cell on the right
and on the left of each of the two pairs of cells which
occupy the middle of the fore edge of the frond, becomes
the seat of fresh cell-multiplication, and is the cell of the
first degree of a pinna of the frond. Each of the new
shoots is alternately more strongly developed, thus changing
the direction of the bifurcation to the right or to the left.
The Aveaker one is pushed on one side so as to appear to be
lateral. The continual change in the direction of the less
vigorous bifurcations causes the feather-like form of the
frond, whose segments (as is well known) are in no species

14

210 HOFMEISTER, ON

exactly opposite to one another. The position of the first
lateral bifurcation on the mid-rib is not constant in any
species ; in Pteris aquilina it is more often to the left, in
Aspidium jilicc-mas to the right. The principal segments of
the fronds, however, taken in relation to their subsequent
ramifications, are very regularly antidromal : on the pinna3
to the left of the axis of the frond the first segment of the
second degree, or the first tooth of the margin, is on the
right : on the pinnae to the right of the axis it is on the
left.

Prom the first commencement of the frond its growth
in thickness is most vigorous behind. Its mathematical
longitudinal axis is not identical with the morphological
one i it does not coincide with the surfaces of contact of
the masses of cells, produced by the multiplication of the
cells of the second degree, which are turned towards the
front and back surfaces of the frond. At the time of the
commencement of the formation of the blade of the frond,
which is produced by the widening of its apex, the cell-
multiplication in a longitudinal direction increases on the
hinder surface of the frond. It exceeds that which takes
place on the front surface and thus leads to the commence-
ment of the rolling inwards of the frond (PL XXIX, fig. 1),
which is completed by the stretching of the cells of the
hinder surface which shortly afterwards takes place. Con-
temporaneously with the commencement of the rolling
inwards, the axile longitudinal rows of cells separate them-
selves by the cessation of transverse division, and become
transformed into the simple vascular bundle which traverses
the stem and mid-rib of the frond. Pour cells of the
adjoining parenchyma are about equal in length to one of
the cells of the rudimentary vascular bundle. This latter
passes through the morphological longitudinal axis of the
young frond, near its front surface. It is concave in a
transverse section, open towards the front (PI. XXIX,
fig. 14).

During this development of the frond, the first root also
has grown considerably. Its axile rudimentary vascular
bundle becomes visible contemporaneously with that of the
frond. The two meeting together in their entire breadth

THE HIGHER CRYPTOGAMIA. 211

underneath the terminal bud, — which in the meantime has
become developed into a cellular wing, — form a connected,
slightly curved, string of cambium, upon which the wing is
attached sideways (PL XXIX, fig. 1).

Now whilst the cellular layers surrounding the embryo
are ruptured by the longitudinal growth of the frond and
root, the cells of the primary axis also become consider-
ably elongated, so that the germ-plant is removed from
the prothallium as if borne upon a short stem ; an appear-
ance which brings to mind the normal process in Salvinia,
The innermost cells of the primary axis adjoining the vascular
bundles of the frond and of the root assume a prosenchy-
matal form (PL XXIX, fig. 1), and at a later period become
woody scalariform cells, so that the ligneous body of the
germ-plant has a blind-ended short prolongation reaching
into the primary axis.

The growth of the stem-bud, which is rapid in com-
parison with what occurs in other ferns, and which is
observable whilst the embryo is yet enclosed (PL XXVIII,
figs. 4, 5), increases still more after the latter has emerged
from the prothallium ; the end of the stem becomes a
somewhat slender cone (PL XXIX, fig. 1). The forma-
tion of the second frond commences even before any
thickenings of the membrane make their appearance in any
of the cells of the rudimentary vascular bundles of the
germ-plant. The second frond originates in the multipli-
cation of a cell of the apex of the stem situated on that
side of it which is turned away from the point of attach-
ment of the first frond, and distant from the latter by about
half the circumference of the stem. The cell-multiplication
of the second, and of all the subsequent fronds, follows the
same rule as that of the first : it begins by the continually
repeated division of the cell of the first degree, by means
of septa inclined alternately towards and away from the
top point of the stem. After the rudiments of the stipes
of the frond are fully formed, the apical cell divides by
longitudinal septa at right angles to the fore and hind
surfaces ; in all the cells of the thus expanded fore-edge,
division occurs by septa inclined alternately towards the
upper and under surfaces of the frond.

212 HOFMEISTER, OX

Almost contemporaneously with the appearance of the
second frond, numerous cellular hairs are seen upon the
terminal bud of the stem, which have been previously
visible, although more sparingly, upon the first frond.
Having regard to their position and their centripetal deve-
lopment, they are undoubtedly analogous to the scales of
other ferns, which indeed also appear primarily elsewhere
under the form of simple rows of cells. * In Pteris
aqidlina, Biclsonia rubiginosa, and Balantium Karstenianum
they do not progress beyond this primary stage of develop-
ment.

From the time of the formation of the second frond
until the commencement of that of the third, the longitu-
dinal growth of the axis increases considerably, as it does
with each successive frond during the entire life of the
plant, unless prevented by unfavorable influences. At
this time, if not (as is not unfrequently the case, PL XXIX,
tig. 1) even before the formation of the second frond, a
twisting of the stem takes place. If the young stem is
supposed to be horizontal, the hinder surface of the first
frond is turned downwards ; the rudimentary frond was
parallel to the surface of the prothallium.f By the torsion
of the axis the direction of the third frond, and sometimes
even of the second, is turned away from it to the extent of
00°. Henceforth the fronds are inserted on the sides of
the creeping stein, the fraction \ representing as before
their mode of arrangement. The plane of involution of the
budding stem (that plane in which all the turns of the
incurved leafy surface lie, and which is perpendicular to
the leafy portion of the frond) is at first radial to the axis
of the latter. This plane, however, soon stands at right

* I will return to this subject hereafter. Multicellular hairs with intercalary
cell-multiplication, even in the direction of the breadth and thickness, occurs
here and there even on the leaves of phsenogams {e.g. Begonia, and the calyx
and corolla of Hibiscus Trionum). My observations do not confirm Kunze's
opinion that the shoots at the base of the stipes of Hemitelia cupensis, which
resemble the fronds of Trichomanes, are transformed scales. The reasons
therefore which induced me to consider the scales as leaves, and the fronds
consequently as leafy branches, fall to the ground. The scales are only a kind
of hairy covering; certainly a very highly developed one, as they frequently
contain chlorophyll; for instance in Platy cerium.

f It is self-evident that in speaking thus of the direction of the frond no
account is taken of the secondary curving upwards of the stipes to the light.

THE HIGHER CRYPTOGAMIA. 213

angles to the axis, on account of the rapid horizontal
longitudinal grow.th of the stem, which far outstrips the
development of the frond ; and the result is that the sur-
faces of the frond are parallel to the axis. The stalks even
of the first fronds exhibit the appearance* which occurs in
the stipes of almost all fronds, that is to say, prominent
bands of loose cellular tissue having the intercellular cavi-
ties filled with air pass along the side edges of the stipes ;
which bands are in connexion with, and of the same nature
as, the inner parenchyma, which latter, except where it is
traversed by the bands, is enclosed by a firm cortical
tissue (PI. XXX, figs. 7, 9). The creeping stem of Pteris
aquilina (PI. XXX, fig. 3), and the stems of the exotic
DicksoniEe, which are similar in their habit, exhibit the same
quality. The lateral ridges of the stem pass directly into
those of the fronds (PL XXIX, fig. 14).

At an early period the germ-plant exhibits that prema-
ture vigorous development of the peripheral cellular layers
of the stem in the immediate neighbourhood of its terminal
bud, which afterwards has a marked effect upon the form
and position of the apex of the stem. The growth in
thickness of the cortical tissue of the next younger portion of
the stem is very rapid, and by the time that the third
frond is developed, the apex of the stem appears to be
sunk in that tissue (PI. XXIX, fig. 6).

The internal structure of the young stem, like that of the
first frond, is very simple. Prom the point of junction of
the vascular bundles of the first frond and first root there is
developed a central vascular bundle, traversing the young
stem (PI. XXIX, figs. 5, 6, 7), from which the transformation
into vascular bundles of the strings of cellular tissue which
pass into the newly-formed fronds commences, and on the
outer surface of which the development of new adventitious
roots begins (PI. XXIX, fig. 6). The direction of the second
and of the next following root diverges by about 90° from
a plane passing through the first frond and the longitudinal
axis of the stem (PL XXIX, fig, 6). The subsequent
roots exhibit no trace of this regular arrangement.

After the formation of from seven to nine fronds, the

* Karsten, ' Vegetations-organe der Pahuen,' p. 129.

214 HOFMEISTER, ON

stem becomes forked by the division of its punctual vege-
tationis. Eacli branch of the fork increases rapidly and
considerably, and about equally, in thickness. The first
frond of each is usually situated to the right hand (PI.
XXIX, figs. 10, 11). From this time forth the course of
the vascular bundles of the stem is a compound one. The
lateral opening of the central vascular bundle becomes
enlarged (PI. XXIX, fig. 8). Its upper half is soon sepa-
rated from the lower; the vascular bundle is prolonged,
whilst the tissue of the bud of the stem remains paren-
chymatal. The stem has now two flat vascular bundles
(PI. XXIX, fig. 9) parallel to the axis, which here and
there split into thinner forked branches which soon unite
again (PL XXIX, fig. 9'). When the furcate shoots
have attained a length of about three inches, and their
transverse diameter is about two lines wide, the two large
vascular bundles send out less vigorous bundles which take
a direction nearer to the bark, and of which the uppermost
one, which passes above the axile bundles, is somewhat more
fully developed, and is about equal in breadth to the latter
(PI. XXIX, figs. 12, 13). The cortical vascular bundles
anastomose in the vicinity of the place of insertion of each
frond, and thus form a hollow cylindrical network of elon-
gated meshes. But no connecting branches between them
and the axile bundles are to be found anywhere in the
stem. The latter follow an entirely isolated course within
the creeping steins ; ramifications from them enter the
fronds, and it is only these ramifications which are
met inside the stipes by ramifications from the cortical
vascular bundles. Roots originate only from the latter
bundles.

The stems of fully grown plants exhibit, in all essential
points, the same distribution of vascular bundles. The
number of the peripheral ones amounts to as many as
twelve. The two uppermost of the latter are blended to-
gether for the greater part of their course, and thus form a
wide bundle, which lies in the same vertical plane as the
primary axile bundles. Two masses of cells almost
parallel to these primary vascular bundles, and situated
between them and the peripheral vascular bundles, become

THE HIGHER CRYPTOGAMIA. 215

very woody, like bast-cells. Their very thick walls,
which are pierced by pits or canals, assume a brown
colour throughout. Thin sections of them are of a
beautiful golden yellow ; when seen in a mass they
are almost black. The axile region of the stem thus
appears, even to the naked eye, to be distinctly separated
from the bark by a thick hard sheath of vascular bundles,
which has a fissure-like longitudinal opening only on each
of the two sides parallel to the outer longitudinal bands of
the stem (PI. XXX, fig. 3). One of these fissures is
often closed by an amalgamation on one side of the two
halves of the sheath of vascular bundles. The upper half
of the sheath is tolerably flat ; the lower one has the form
of a furrow. During the transformation of the parenchy-
matal cells of the end of the stem into bast-cells, air-
bubbles are formed (PL XXX, fig. 12), between the walls of
the latter, in the interior of small irregularly-defined inter-
cellular cavities. These air-bubbles disappear when the
thickening of the walls commences.

The outermost cellular layers of the bark also assume a
deep brown colour, but without becoming prosenchy-
matous, and without any material thickening of their walls.
Those portions only of the tissue which pass towards the
lateral longitudinal ridges do not assume this brown colour,
which extends to the depth of one-eighth of a line into the
cortical tissue. The portions just mentioned, like the
parenchyma of the interior of the stem, remain of a dazzling
white : they contain starch, and their intercellular cavities
are filled with air. Here and there in this tissue, and
sometimes also in the brown-coloured outer cortical layer
spindle-shaped groups of combined cells become trans-
formed into thick-walled bast-cells, similar in all respects to
those of the sheath of vascular bundles.*

As the vascular bundles in the growing stem become
more complicated, so also do those in the stipes of the
fronds. As in the first, so also in the other fronds of the
young plant up to the twelfth, the vascular bundles unite to-

* Mold objects to these cells being called bast-cells (' Vermischte Schriften,'
p. 116), but in their form and mode of development they agree exactly with the
bast-cells of phsenogams.

216 HOFMEISTER, ON

gether to form a single one. The transverse section of
this single bundle has the shape of a horse-shoe, of which
the opening is originally turned towards the apex of the
stem-bud, but which in consequence of the rapid longi-
tudinal development of the latter, and of the curving up-
wards of the frond, appears at a later period to be parallel
to the longitudinal axis of the stem. After the splitting
of the primary vascnlar bundle, and the appearance of
cortical vascular bundles in the stem, there arise ramifica-
tions of both the axile bundles, of the wide bundle above
them, and of the rest of the cortical vascular bundles of the
adjacent longitudinal half of the stem (PI. XXX, figs.
1" to V, and fig. 2). The sheath of vascular bundles also
sends out prolongations into the stipes : from the upper
as well as from the lower group of brown bast-cells the
same transformation of the tissue advances in a direction
parallel to the longitudinal axis of the frond (PI. XXX,
fig. 7). At a short distance above the place of insertion
of the frond, both longitudinal strings of ligneous tissue
unite to form a single one of which a transverse section
exhibits the shape of the letter T having the two branches
of its head turned to the lateral longitudinal ridges of the
frond (PL XXX, figs. 8, 9). The hind angle of the T
includes the ramifications of the two axile primary bundles
of the stem ; the fore angles those of the wide cortical
vascular bundle which runs off in the top line of the hori-
zontal stem, as well as the branches of the cylindrical cortical
vascular bundle immediately adjoining. In front and
on the outside of the head of the T, run the bundles which
sent forth the cortical bundles underneath the place of inser-
tion of the frond. In the lowest part of the stipes, under-
neath the point of junction of the prolongations of the
vascular sheath, all these vascular bundles anastomose in
a radial direction • above this point only in a tangential
direction. Each of the primary vascular bundles sends
two proportionally thin cylindrical branches into the frond
(PI. XXX, figs. 2,!,e). All four soon unite to form a wide
vascular bundle concave behind (PI. XXX, figs. 8, 9).
A similar bundle is formed by the junction of those bundles
which are enclosed by the fore angle of the T-shaped mass

THE HIGHER CRYPTOGAMIA. 217

of brown cells. It is this distribution of the tissue com-
posing the stipes which produces the well known figure of
the eagle seen on an oblique section.

Delicate longitudinal sections through the terminal bud of
the stem of Pteris aquilina, exhibit with the greatest clear-
ness the transformation of the originally homogeneous
parenchymatal tissue into vessels and bast-cells. The in-
vestigation is very much facilitated by the course of the
inner one of the two primary vascular bundles, which is
straight and parallel to the axis. According as the section
is taken parallel to the surface of the earth, through the
longitudinal ridges of the creeping stem, or at right angles
to this direction, the wedge-shaped cell which encloses
the apex of the flatly conical deeply buried terminal bud
is seen either on its three-sided front aspect (PI. XXXI,
fig. 5), or its four-sided lateral aspect (PL XXXI, fig. 4).
The funnel-shaped depression, at the bottom of which the
terminal bud is seated, is strongly compressed from above
and below. The walls of the depression are thickly clothed
with scale-like hairs. The erect ends of the hairs, which
are closely pressed against one another, and fastened to-
gether by a hardened mucilage secreted from the bud,
entirely close the mouth of the funnel, and shut off the
delicate young portions at its base from the outer air. The
end of the stem in its longitudinal growth forces its way
through the toughest clay, without injury to the delicate bud
buried in its apex.

The clearly defined mode of arrangement of the cells of
the second degree, and of their derivatives, affords an im-
mediate explanation of the deep depression of the terminal
bud. The cell of the first degree is wedge-shaped (PI.
XXXI, figs. 2 — 5), as is manifest by comparing its apical,
front, and side aspects. It is bounded by three curved
surfaces, the upper free wall of the cell representing a
portion of a spherical surface enclosed by two flattened
arcs, and the side-walls being two segments of a conical
surface. The septa which arise in the cell, and which are
alternately parallel to the one and the other of the simple
curved lateral surfaces, form cells of the second degree,
having the shape of the fifth part of an oblique hollow

318 H0FME1STEK, ON

cone. These divide successively by means of longitudinal
septa which are parallel to each one of their small lateral sur-
faces, and diverge strongly from the radii of the stem, into
from three to five cells, adjoining the cell of the first
degree (PI. XXXI, fig. 3 *) ; a form of multiplication in
which variations sometimes occur by which the next step
in the development is anticipated (PL XXXI, fig. 2). The
newly-formed cells then divide gradually by means of septa
parallel to the lateral surface of the apical cell into twos ;
those cells which are situated anteriorly to the middle of
the sides of the apical cell dividing sooner than those
adjoining the lateral corners. The cells thus formed, whose
increase in height and in width (?. e., parallel to the lateral
surface of the apical cell) far exceeds their increase in thick-
ness, divide by means of transverse septa into low, almost
cubical, inner cells, and elongated outer cells, with a free
outer wall (PI. XXXI, figs. 4, 5). The expansion and
multiplication of the cells of each of the groups derived
from a cell of the second degree, preponderate considerably
in the lower portion and in a transverse direction ; and
the same thing occurs in the cells derived from the youngest
of the four cells of the second degree, whose free outer
walls compose the conical interior portion of the stem-bud
(PL XXXI, figs. 4, 5). In the longitudinal section of the
stem the boundary lines which enclose each such group of
cells exhibit strongly protruding angles on the side turned
away from the apex of the stem : the side walls of the cells
composing the outer surface of the stem-bud, are inclined
inwards towards their summits. In the next older group
of cells the direction of the suddenly-augmented cell-multi-
plication is reversed. Here the cells of the circumference
often divide repeatedly by means of septa parallel to the
chord of the arc of the outer wall, and perpendicular to the
side-walls. This is a growth in thickness, an increase of
the cortical tissue in a direction at right angles to the
axis, but in consequence of the unusual direction of the
cells in which it occurs, it takes place at first apparently
in an upward direction. The bud becomes surrounded by
a high, narrow, annular wall. The growth of the latter is
particularly active in the direction of a plane cutting the

THE HIGHER CRYPTOGAMIA. 219

lateral bands of the stem at right angles ; here the internal
septa of the annular wall become perpendicular, or even
overhanging. Its cells appear arranged in concentrical
scaly layers round the middle point of the stem-bud.

During the formation of the annular wall the activity of
cell-multiplication in the longitudinal direction (i. e., in the
direction of lines drawn in a radiating manner from the
apex of the stem-bud along its sides) increases, and
obliterates the arrangement of the cells visible in the apical
aspect of the youngest portions of the bud, viz., the system
of flattened arcs surrounding the middle point of the stem.
In its place the arrangement in (apparently radial) longitu-
dinal rows becomes more manifest ; this is produced by the
repeated division of the cells by means of septa at right
angles to the outer surface, and perpendicular to the radial
planes passing through the axis of the stem.

The prolongation of the two primary axile vascular bun-
dles begins to be differentiated from the rest of the tissue
at a very little distance beneath the terminal bud, and in
or near the mass of cells derived from the eighth-youngest
cell of the second degree. The separation of the peripheral
vascular bundle commences somewhat further from the
apex of the stem. Both phenomena arise from the fact,
that in the strings of cells which are transformed into
vascular bundles, the transverse division which continues
to take place in the neighbouring tissue, diminishes and
ceases, whilst the division by means of longitudinal septa is
hastened. The rudimentary vascular bundles appear there-
fore as streaks of narrow elongated cells, whilst in the cells
of the remaining tissue no one of the three dimensions
preponderates to any great extent (PI. XXXI, figs. 4, 5).
Certain cells of the vascular bundles arranged in longitu-
dinal rows, become widened at a very early period. After-
wards they are transformed into the scalariform cells which
form the principal mass of the perfect vascular bundle.
In the first instance they are placed one upon another, and
furnished with horizontal transverse septa : they assume
their permanent spindle shape even before the first traces
of thickening layers are visible upon their inner walls (PI.
XXX, fig. 12 ; PI. XXXI, fig. 1). The first appearance

220 HOF5IE1STER, ON

of the thickenings of the wall is in the form of delicate
transverse streaks, and commences long before the termina-
tion of the longitudinal growth of the cell, and even during
the existence of the parietal nucleus and of the strings of
granular mucilage proceeding from it (PI. XXXI, fig. 1).

Long before the appearance of the first traces of the
thickenings of the walls of the scalariform vessels, spiral
thickenings are visible in certain cells arranged in groups
of twos or threes and which at an early period become
spindle-shaped. It is very clearly seen that the formation
of the spiral band proceeds gradually from the lower to the
upper end of the cell (PI. XXX, fig. 12). In each vascular
bundle these small groups of spiral vessels are formed : one
axile group is formed in those vessels which are circular in
a transverse section, and three are usually formed in those
bundles whose transverse section is elongated ; one of such
groups being in the centre, and the others in the foci of
the figure presented by the transverse section, and which
bears a distant resemblance to an ellipse.

The great expansion of the cells of the vascular bundle
which go to form the scalariform vessels, causes such a com-
pression of the intermediate, narrow, prosenchymatal cells,
that in some instances the entire cavity of the latter is
obliterated.

A transverse section of the youngest portion of a vascular
bundle taken at a point near the terminal bud where the
thickening layers are visible only in the spiral vessels,
exhibits a considerably larger number of cells than is seen
in the same vascular bundle at a distance of about a line
and a half from the terminal bud after its scalariform vessels
are completed (PL XXX, figs. 10, 10';). A similar state of
things exists in the vascular bundles of the stipes. Trans-
verse sections of the compressed cells, provided the cavities
of the latter are not quite obliterated, bear a considerable
resemblance to the lenticular cavities between two pits of
coniferous wood (PI. XXX, fig. 2, between the two wide
vessels) .

The course of the vascular bundle nearest to the middle
of the stem (i. e. of the upper one of the two primary ones),
is almost exactly parallel to the longitudinal axis close

THE HIGHER CRYPTOGAMIA. 2:21

under the bud of the stem. But in consequence of the
subsequent growth in length and thickness of the interior
of the stem, the other axile bundle, and still more the cor-
tical bundles, are bent strongly inwards towards the longi-
tudinal axis of the stem as long as their course passes
within the prematurely developed peripheral tissue. This
bending usually amounts to 99° in the cortical bundles
(PI. XXX, fig. 4 ; PL XXXI, fig. 1). A transverse section
passing through, or just over, the apex of the bud, exhibits
the vascular bundles which run almost horizontally to the
apex, in the form of from six to eight light streaks united
in a stellate maimer.

Soon after the appearance of thickening layers in those
cells of the axile bundles which have become widened into
scalariform vessels, there ensues such a considerable growth
of the cells of the interior of the stem, that the dispropor-
tion of the latter to the peripheral cellular layers disappears.
The bent portion of the cortical vascular bundles takes a
straight course ; the height of the axile cells becomes
almost equal to that of the cortical cells of the same age ;
which latter cells had far outstripped the former in
development, especially in the thickening of the cell-
membrane, as is perceptible in the peripheral vas-
cular bundles. As the growth of the interior of the
stem (by means of the extension of its cells) surpasses
that of the bark, which was prematurely developed by more
vigorous cell-multiplication, the cells of the interior are
three or four times longer than the peripheral cells. The
process may be considered as a pushing outwards of the
funnel-shaped depression around the terminal bud. It
occurs in like manner in Isoetes, Cycas, Mamillaria and
elsewhere, but much less distinctly on account of the close
crowding together, of the appendicular organs.

The formation of new fronds always takes place above
the point of origin of the youngest scales. At sonic dis-
tance from the top cell of the apex of the stem, and sepa-
rated from the latter by from three to six cells, the mother-
cell of the frond is first visible in the form of a slight
elevation above the flat conical surface of the bud (PI. XXXI,
fig. 3). The first step in the formation of a frond however

222 H0FME1STER, ON

very probably consists in the occurrence from time to time
of the division of a newly formed cell of the second degree
by means of a slightly convex longitudinal septum, turned
towards the cell of the first degree, which cuts off from the
cell of the second degree a daughter- cell, whose form coin-
cides with that of the apical cell of the stem (PL XXX,
fig. 2). The rudiment of the frond bears considerable re-
semblance to the end of the stem in the arrangement of its
cells, but is distinguishable by the greater curvature of its
arcuate surface, and by the very early appearance, (although
at first in small quantity), of chlorophyll in its cells. The
growth of the frond in length and thickness is at first very
slow. The rapidly elongating apex of the stem soon leaves
it behind. Whilst the premature development of its cor-
tical tissue commences on the side turned to the young
frond, the wall-like elevation of the circumference of the stem
in the neighbourhood of the terminal bud pushes itself at
an early period into the space between the two. The frond
and the end of the stem which at the first appearance of
the former are enclosed in the same depression of the bark,
are now each of them situated at the base of a special
funnel-shaped depression. The tips of the scales which
clothe their walls protrude above each depression in a peni-
cillate maimer (PI. XXX, fig. 5).

Whilst the germ-plant in the first year produces as
many as twelve slender fronds whose development is con-
tinually progressive, the development of the fronds of older
plants, which is frequently interrupted by long periods of
cessation, requires several years. It is a rule, departed
from only in cases of sudden alteration of the conditions of
vegetation, (such as the ploughing up of the ground of a
wood), that each shoot of the mature plant sends out yearly
only one frond.* New fronds are produced towards the
end of the vegetative period which lasts from April till
October. In the first year the frond assumes no greater
development than that of a low, laterally flattened, green
wart of cellular tissue, situated at the base of a depression
of the bark of the stem, distant at the most not more than
a line from the apex of the stem. In the following year

* See A. Braun, c Verjiingung,' p. 63.

THE HIGHER CRYPT0GAM1A. 223

(until the end of May) the stem rapidly elongates to the
extent of about an inch, and during this period the portion
of the stipes of the young frond which afterwards
assumes a brown colour, is formed : it is a cylindrical
body, one or two inches high, having a vertical direction
produced by violent curvature close to its place of insertion,
and clothed with yellowish- white scales (PL XXIX, fig. 14).
After the removal of the latter a flat furrow is visible at the
apex of the young frond on the side turned towards the
stem, in which the rudiments of the lamina of the frond
are closely folded in tile form of a flat cellular mass, about
one eighth of a line long, exhibiting two or three furcate
ramifications (PL XXX, fig. 6, 6 h). Towards the end of
the second vegetative period this cellular mass attains the
length of one line, and makes from ten to twelve furcations,
alternating to the right and to the left hand. The further
development of the frond goes on in the spring of the third
year, at the end of May in which year it appears above the
surface of the earth, delicately rolled up like a crosier, and
complete in all its parts.

Roots are developed only from the cortical vascular bun-
dles of the stem of mature plants, and in fact only from the
points of junction of their meshes. Their rudiments are
formed close under the terminal bud, at the point where the
course of the cortical vascular bundle exhibits its inward
curvature (PL XXXII, fig. 1). Here cell-multiplication
commences in one of the outer cells of the cambium bun-
dle, similar to that by which the first root of the germ-plant
is formed. As in that case, the three different kinds of
septa of the cell of the first degree stand at right angles to
a radial plane passing through the longitudinal axis of the
stem. A septum is formed tinned towards the vascular
bundle from which the root is developed, and making an
angle of about 30° with the root. This septum has the
form of the third part of the surface of a truncate cone,
and its formation is followed by that of a curved septum
inclined in an opposite direction, this again is followed by
the formation of an almost flat transverse septum at right
angles to the longitudinal axis of the root, and diverging
from the two former by about 60°. The form of the pri-

224 HOFMEISTER, ON

mary cell of the root agrees with that of the apical cell of
the stem, except that the side-walls of the former are more
strongly curved (PL XXXI, fig. 6 h ; PL XXXII, fig. 1 ").
The layers of the root-cap, which on account of the more
vigorous growth at their median point are convex outwards,
are developed from the cells of the second degree, which
latter are formed by the production of flat septa parallel to
the basal surface of the primary cell. The permanent main
portion of the root is produced by the continual division of
those cells which have the form of the third part of a
hollow cone. The latter cells are first arranged in parabo-
loidal layers, which in the one longitudinal moiety of the
root protrude for about half the length of a cell beyond the
layers of the other moiety of the root. In the cells derived
from the third oldest cell of the second degree,this symmetri-
cal arrangement is changed into a homogeneous one, whilst
transverse septa parallel to the primary septa appear in all the
cells of the layer (PL XXXII, fig. 1 h). The mode of dif-
ferentiation and formation of the axile vascular bundle, and
the delay which at first occurs in its longitudinal develop-
ment compared with that of the bark (a delay which is
afterwards compensated by expansion), are common to both
the root and the stem.

Ramifications of the root spring from its vascular bundles
in the same manner as the roots spring from the cortical
vascular bundles of the stem. The roots of the second
degree, as well as their ramifications, which are not of
frequent occurrrence, are arranged in two lines.

The greater the age attained by a shoot of the Eagle
Pern — whether such shoot proceed directly from a pro-
thallium, or from a bud, or whether it be the single branch
of a forked stem — the greater is the tendency to furcation
of its terminal bud. Ultimately, in really old individuals,
frond- formation ceases entirely on the furcate branch when
more strongly developed. Only the more delicate forked
shoots which are placed alternately to the right and to the
left bring forth fronds ; the first one being always in the
inner angle. The naked unbranched terminal shoots of
those plants whose sympodium (which has the appearance
of a principal axis) bears no fronds, is developed with ex-

THE HIGHER CRYPTOGAMIA. 225

treme rapidity, and produces an abundance of roots. Un-
branched terminal shoots of this kind, of from six to ten
inches long, are not rare. In these shoots the lower part of
the annular wall which surrounds the terminal bud, pro-
trudes itself forward in a labiate form, so that it eventually
lies upon the upper surface of the gradually flattened
shoot (PI. XXX, fig. 4). The distribution of the vascular
bundles in these unbranched, frond-less ends of shoots,
exactly corresponds with that of the frond-bearing stem ;
a convincing proof that the arrangement of the vascular
bundles in the stem is not dependent upon the position of
the appendicular organs, or the number and form of the
bundles occurring in such organs.*

The two wide axile vascular bundles are entirely devoid
of branches in each joint of the sympodium. At each fork
they send out into the more delicate shoot vigorous branches
which constitute the axile vascular bundles of the latter
shoot. I have met with sympodia four feet long devoid of
fronds. The distances between two furcations are very un-
equal, and manifestly dependent upon the amount of
nourishment being greater or less. The entire ramification
of the plant, so far as it depends upon the furcations of the
terminal buds, and the position of the fronds on these
ramifications, correspond entirely with the pinnations of the
blade of the frond. These latter are only distinguishable
in their first rudiments from the furcations of the terminal
bud, by the upward direction of the growth of the frond :
they do not differ in their cell-succession.

Buds from which new shoots may be, and are developed,
are found in Pteris aquilina only on the under side of the
stipes ; sometimes low down, sometimes higher up. Some-
times they appear so early and are so near the place of in-
sertion of the frond that at first sight they appear to belong

* The same conclusion may be drawn from the condition (observed by H. v.
Mold, 'Verm. Schriften,' p. Ill,) of the upper ends of the vascular bundles of
all ferns, especially of those with creeping stems and bilinear phyllotaxis (see
PI. XXXV, fig. 4) : although the relations in question do not elsewhere stand
out in so marked a manner. The conclusion given above would be valid even
if the objections raised by Mettenius against my views of the mode of ramifi-
cation of Pteris aquilina ('Abhandl. K. Sachs Ges. der Wiss.,' b. yii, p.
C21,) could be maintained, which, however, as I shall hereafter show, is not
the case.

15

226 H0FME1STER, ON

to the stem. They originate from the multiplication of one
of the cells of the free outer surface of the very young
frond, and are situated on its back or at the edges,* they
occur long before the first rudiment of the vascidar bundles
separates itself from the rest of the tissue (PL XXXII,
fig. 2). The divisions of the primary cell of the new shoot
follow the same rule as those of the apical cell of the
mother-axis. When the development of the bud goes on
slowly, the cortical tissue closes almost entirely over it
(PL XXXII, fig. 3). An accurate observer however may
even then discover the passage leading to the punctum
vegetationis, which is merely stopped up by entangled and
agglutinated scales (PL XXXII, fig. 34) : the passage is
blocked up by the drying of a portion of the mucilage,
which these buds of Pteris aquilina secrete in abundance.

Aspidium filix-mas. — The rudimentary and apical cells of
the first, and of all the succeeding fronds of this fern, divide
by means of septa inclined to the edges of the frond alternately
to the right and to the left ; the line in which each new sep-
tum cuts the next older one, is radial to the axis of the stem.
As far as can be gathered from the result of numerous
observations, the first septum which appears in the cell of
the first degree, is inclined to the left,f and turned towards
the next older frond (PL XXVI, fig. 14). This form of
division continues until the completion of the rudiment of
the stipes. When the formation of the blade of the frond
commences, septa make their appearance in the cell of the
first degree, and in the cell next to it of the second degree,
which septa are inclined alternately towards the front and
the hind surface of the frond. Thus the arrangement of
the cells in the growing portions of the frond is coincident

_ * Upon the supposition of the adventitious bud being produced by the mul-
tiplication of a cell in the interior of the tissue, for instance, a cambial cell of
a vascular bundle, the gemmae of ferns would not be adventitious buds. But
this definition is too narrow, and could not be employed in many of the instances
which occur in phsenogams.

f Following Braun's rule (' N. A. A. C. L.,' xv, p. 220,) of using the ex-
pressions right and left with reference to the direction of the development of
the organic body in question, I call that margin of the frond the right margin
which would be on the right hand of the observer, supposing him to be
placed in the longitudinal axis of the frond, with his face to the upper surface.
This margin of the frond is the front margin, turned towards the ascending
leaf spiral.

THE HIGHER CRYPTOGAMIA. 227

with that above described in Pteris aquilina, and the mode
of ramification of the blade of the frond is the same as in
the latter plant (PL XXVI, fig. 8).

The germ plant of Aspidium jilix-mas developes its second
frond at a distance of about a third of the circumference of
the stem from the first. At the point of junction of the
vascular bundles of the first frond and of the first root,
there is formed a vascular bundle, which, after traversing
the axis for a short distance, bends off into the second
frond (PL XXVI, fig. 13). The second root is developed
from that part of the vascular bundle which is situated in
the stem, and at some little distance beneath the place of
insertion of the second frond. The third frond diverges
from the second, and the fourth again from the third, at
about 120° to the right, so that the fourth stands vertically
over the first. At the bending-point of the vascular bundle
which passes out of the longitudinal axis of the stem into
the second and succeeding fronds, there is produced a
vascular bundle, which, after passing along the axis of the
stem for a short distance, bends off into the next younger
frond. Transverse sections of the stem exhibit only one
vascular bundle (PL XXVI, fig. 12). The length of the
stem between each two of the first four, five, or six fronds,
is much greater than between two of the subsequent
fronds.

The thickness of the stem increases suddenly and con-
siderably above the fifth or sixth frond. This rapid growth
in thickness takes place whilst the next younger fronds, the
seventh to the tenth, continue in the state of buds. Owing
to the vigorous and rapid peripheral development, the
apical region of the stem becomes almost a flat surface, in
the middle of which the outermost point of the stem pro-
trudes (PL XXVI, fig. 15). Around it the youngest
fronds are arranged spirallv. Henceforth the end of the stem
retains this form (PL XXVI, fig. 19 ; PL XXVII, figs. 3, 4).

The flattening of the terminal bud depends upon the
fact that the superficial cells of the conical cellular mass
divide repeatedly by septa parallel to the chord of the
arcuate free outer wall — (a mode of cell-multiplication
which increases continually from the apex of the cone to its

228 HOFMEISTER, ON

base where it suddenly ceases, and which is accompanied
by a series of divisions proportionate in number to the in-
crease of the circumference of the cone and produced by
longitudinal septa radial to the axis of the stem) — whilst the
division by transverse septa at right angles to those chorda!
longitudinal septa occurs proportionally seldom. The
conical terminal bud grows upwards by the formation be-
neath its entire outer surface of a layer of cells having the
form of a conical covering thicker towards the base, whilst
the angle of inclination of the cone becomes continually
narrower. At a latter period, after the formation of the
rudiments of several cycles of fronds, the longitudinal
growth of the stem is so much accelerated by the active ex-
tension of the cells of the axile tissue (accompanied by the
formation of transverse septa in the peripheral cells) that it
exceeds the previous increase in thickness. The cortical
region is pushed outwards by the longitudinal extension of
the middle of the stem, and passes from the form of a very
blunt cone into that of a cylinder ; this complete inversion
of the mode of growth is caused by the change of direction
of the expansion and multiplication of the cells. The
process (which is common to all stems with flat terminal
buds, e. g., Polytrichum, Dracaena) is more easily seen in the
slender stem-ends of the germ-plants and gemmae of
Aspidiuni filix-mas or Asplenium jilix-femina, than in the
stems of older individuals of the former plant which become
too thick.

After the stem of the germ-plant has increased in thick-
ness the arrangement of the subsequent new fronds changes
from the \ to the f arrangement. At the same time the
distribution of the vascular bundles in the stem becomes
different. At the place where the vascular bundle which
passes into the last frond of the \ arrangement turns side-
ways, strings of the cambium which afterwards forms the
vascular bundles separate themselves in the direction of
each of the three next fronds, and run parallel to the longi-
tudinal axis of the stem (PI. XXVI, fig. 15). A trans-
verse section of the stem at this spot exhibits three vascular
bundles arranged in a circle (PI. XXVI, fig. 16).

The rudiments of the vascular bundles which pass to all

THE HIGHER CRYPTOGAMIA. 229

the succeeding fronds are already formed whilst the fronds
are still in the condition of very young buds, inasmuch as
from the place where those vascular bundles which pass to
the two next adjoining older fronds bend aside to make
their way out of the stem, the cells of the bud-tissue are
transformed into cambium-strings as far as the younger
frond. Close under the place of insertion of the young
frond the two rudimentary vascular bundles unite to form
a single one (PL XXVI, fig. 9) which after passing through
the stipes for a short distance splits again into two (PI.
XXVI, figs. 10, 11). A vascular bundle passes to the
first frond from the fifth and sixth, and to the ninth from
the sixth and seventh, and so on. Thus the vascular bun-
dles of the young stem represent in their entirety a tubular
net, with rather wide meshes,* from whose angles, simple
vascular bundles pass off to the fronds. A transverse
section of the stem of a seedling of about a year old
exhibits five vascular bundles enclosing a pith.

In the second year the plant develops itself much more
vigorously. Its fronds attain a foot in length ; their
arrangement proceeds normally according to the \% arrange-
ment. Henceforth several vascular bundles occur in each
stipes. In old vigorous individuals as many as five pass
from the knot of vascular bundles which corresponds with
the place of insertion of each frond. The lowest and most
vigorous of these bundles — which, as it originates out of the
lower angle of the knot of vascular bundles, corresponds
with the single bundle of the fronds of the one-year-old
plant — passes near the hinder surface of the stipes, and
divides into two close above the place of attachment of the
frond to the stem, at the place where the protuberant en-
largement of the stipes, characteristic of Aspidium filix-mas,
begins (PI. XXVII, fig. 6). Mature plants produce roots
exclusively from these two vigorous bundles of the stipes.
The stem, which in the first year of the germ-plant sends
out all the roots, afterwards ceases to produce any. Prom
the side angles of each knot of vascular bundles of the
stem two thin vascular bundles pass off into the frond, and

* Mohl, ' Vermischte Schriften,' p. 115.

230 HOFMEISTER, ON

two rather more vigorous ones at a little distance higher
up (PI. XXVI, fig. 20). Both pairs run along the protu-
berant longitudinal ridges of the frond, the former pair
behind, the latter in front (PI. XXVII, fig. 7). The vas-
cular bundles not unfrequently anastomose in the interior
of the stipes. Hence it arises that transverse sections of
the latter sometimes exhibit more than five vascular bun-
dles.

The distribution of the vascular bundles within the stem
remains essentially the same during the progress of the
arrangement of the fronds, except that (as is manifest) the
number of loops increases. The first frond of a cycle
receives its vascular bundles no longer from the sixth and
seventh, but from the ninth and eleventh of the preceding
cycle ; the sixth frond from the first and the third, the
eighth from the third and fifth of the same cycle, and so
on. Or to state it more shortly — the vascular bundles
which pass from the right to the new fronds follow (when
the turn of the spiral is normal, or to the right hand) the
3-numeral fronds ; those which pass from the left follow
the 5-numeral ones. Eight transverse sections of vascular
bundles lie in one plane passing through the stem at right
angles to the axis. In mature plants of Aspidium Jilix-mas,
there is a periodicity in the development of the frond which
is not found in the one-year-old seedling. The growth of
the frond in the former is arrested in winter, but not so in
the latter. The number of fronds which unfold in spring,
and which all grow simultaneously from the end of May
till October, is usually thirteen, corresponding with the
number of the joints of a segment of the spiral in which
the fronds are arranged. A similar state of circumstances
is met with also in some other ferns, as in Asplemum filix-
femina, where the number of fronds is usually eight or
thirteen, and in Aspidium spinulosum and Asplenium TricJio-
manes where eight fronds are usually developed contempo-
raneously. As in Pteris aqitilina, the rudiments of the
fronds are formed two years before their unfolding. In
the first year the stipes only is formed, and in the outer-
most fronds of the cycle about three or five of the pinnae.
In the second year the pinnae of those fronds which are to

THE HIGHER CRYPTOGAMIA. 231

open in the spring are completed in all their parts, and
after the second winter's rest they are fully developed. The
younger fronds of the same season follow step by step in
the same development until the month of June.

The commmencement of the formation of the vascular
bundles takes place in the bud even of very vigorous speci-
mens from the fifth-youngest frond in a backward direc-
tion, and thus, far above, the point at which the longi-
tudinal growth of the stem begins to exceed its growth in
thickness. Thus the whole system of vascular-bundle-
meshes lies at first in an almost horizontal, very flatly para-
boloiclal surface, close under the top surface of the stem,
and nearly parallel thereto. It is only immediately below
the apex that the number of the cells of the tissue of the
stem underneath and within the net of vascular bundles is
increased ; lower down there occurs an expansion of these
internal cells, their longitudinal diameter becoming from
four to five times longer, and their transverse diameter
from two to three times wider. It is only by this increase
(caused by cell-expansion) of the bidk of the pith that the
net of vascular bundles is lifted up by degrees and pro-
jected upon a cylinder. It is easily seen by counting the
cells during and after the transition of the net of vascular
bundles from the form of a paraboloid to that of a cylinder,
that the increase in thickness of the stem is not caused
by any subsequent new formation of parenchymatal cells
either within the pith or in the neighbourhood of, or be-
tween, the rudimentary vascular bundles. It is only in
front of the youngest rudimentary vascular bundles that a
slight multiplication of the cortical tissue takes place, by di-
vision of the peripheral cells (PI. XXVII, fig. 3).

If any radial section be taken through the longitudinal
axis of the stem the side view thus obtained of the apical
cell of the terminal bud is without exception three-sided (PL
XXVII, figs. 3, 4). When viewed from above the upper
surface of the same cell exhibits the like shape (PI. XXVII,
figs. 1, 2). Its form is therefore that of an inverted three-
sided pyramid with an arched upper surface. The appearance
shews (PI. XXVII, figs. 1, 2,) that this cell divides re-
peatedly by septa, having three directions, and turned sue-

232 HOFMEISTER, ON

cessively to one of the lateral surfaces. As far as can be
judged from numerous observations, the succession of these
septa one after another is to the right hand, more seldom
to the left, but ahvays coincident with the spiral in which
the fronds are arranged.

There is yet a second point in which the relation of the
apical cell to its daughter-cells is affected by the frond-
spiral. The apical aspect of the top cell of old speci-
mens of Aspidium filix-mas is very rarely that of an equi-
lateral triangle. One of the sides is usually considerably
shorter than the two others, which latter are nearly of equal
length. The outline of the apical surface is normally that
of an isosceles triangle. Deviations from this form may
be easily traced to the disturbances caused in the older
lateral surfaces of the apical cell by the growth of the
adjoining secondary cells. The one side of the triangle is
formed by the upper edge of the youngest side- wall of the
terminal cell, and the other side by that of the oldest side-
wall of the same cell. The base is formed by the side-wall
intermediate in age between the oldest and the youngest.

The relation of: the length of this base to the younger of
the two sides is in most cases a definite one. The follow-
ing series of measurements will show this. The younger
of the two longer side-walls of the apical cell is the one
always measured. Some of the measurements were made
on the apical cells of buds which had been separated by a
transverse section from the older portion of the stem, and
simply cleansed from the adherent mucilage and scales.
The greater part of the measurements, however, were made
on the transparent membrane formed by the free outer
walls of the superficial cells of the bud. These walls have
a much stronger consistence than those of the inner tissue
of the bud. After a little practice with the microscope it
is not difficult to scrape out from the inside of the terminal
bud the mass of internal parenchyma, consisting of delicate
cell-walls and cell-contents, so as to leave the outer walls
in the form of a connected, slightly arched membrane — ■
(the epidermis, improperly so called, of the young portions
of the plant). The lines of contact of the cell-walls
which have been attached to this membrane are most dis-

THE HIGHER CRYPTOGAMIA.

233

tinctly marked upon the latter in the form of slightly pro-
tuberant ridges, and admit of the most accurate measure-
ments. Each of the following is the mean of at least five
measurements which did not differ from one another by
more than half a micro-millimeter.*

Measurements of the apical cells of Ferns having the ^frond-
arrangement.

—

Base.

Side.

Relation of
the two.

M.M.M.

M.M.M.

Aspidium Jilix-mas,

Spiral

right

33.6476

47.1618

1 : 1.401

33 >3

33

33 •

39.912

56.542

1 : 1.416

33 33

33

33 •

43.3104

61.0986

1 : 1.401

33 3}

33

33 •

45.2312

63.7098

1 : 1.408

33 33

11

33

46.564

66.52

1 : 1.41

33 33

>S

33

49.89

70.6773

1 : 1.416

33 S3

33

33

51.8504

73.6386

1 : 1.42

31 33

11

33 •

52.859

75.0198

1:1.419

33 33

33

33 •

55.7116

78.593

1 : 1.41

33 33

53

33 •

55.7116

79.5336

1 : 1.427

33 33

33

33 "

55.9874

78.593

1 : 1.403

33 33

33

SS •

56.542

79.824

1:1.411

„ spinulosum „

left .

36.6076

51.3022

1 : 1.401

33 33

33

33

40.1194

56.4582

1 : 1.406

33 33

33

right .

43.0526

60.3246

1 : 1.401

33 33

S3

ii '

43.0526

60.8408

1 : 1.413

S3 33

33

33

44.0838

61.7421

1:1.4

33 33

33

left ;

52.0756

73.2152

1 : 1.407

33 33

33

right .

52.6778

74.5487

1:1.401

SS 33

33

33

52.9536

75.5692

1:1.428

Asp I. filix-fem.

33

33 •

33.26

46.564

1:1.4

a

lean . .

1 : 1.4094

This proportion of the base to the sides is that of an
equilateral triangle with an apical angle of 69° 13' 533",
and whose angles at the base are 41° 32' 13'4"; angles
which very nearly approximate to those of a triangle which
is bounded by the chords of two arcs of 138° 27' 41-53' —
(two successive steps of the smaller divergence of the ^ frond-
arrangement) — and by the line uniting the free terminal
points of these chords, which line is the chord of an arc
of 83° 4' 36' 94", being the difference between the larger
and the smaller divergence of the ^ arrangement. The
apical angle of such a triangle is 41° 32' 18-47"; each of

* 1 m.m.m. = 9-0001 millim.

234

HOIWIEISTER, ON

the angles at the base is 69° 13' 50-765"; the relation of
the base to one of the sides is 1 : 1*4067. The divergence
of these numbers from the measurement falls within the
limits of probable error.* The conformity of the angle of
the apical cell of the stem with the divergence of the appen-
dicular organs is not limited to the ^ arrangement. The
calculated relation of the shorter side of the triangular apical
surface of the terminal cell to one of the longer sides is ;

In the | arrangement 1 : 1.618
1 : 1.307
1 : 1.4067
1 : 1.3683
1 : 1.3799
1 : 1.3294

8
f
5

T"3~

8
"2T

1 8
34

2 I

The observed relations are-

—

Base.

Side.

Relation of
the two.

Asp.filix-mas^ arrangement, Spiral right .
j) ,, „ ,, (seedling)
» » '> >> »

» A ii „ right .

» 'ST j> ,, ,,

-

M.M.M.

56.9738

27.8558
36.1298

M.M.M.

74.2464
36.6814
47.7134

1 : 1.307
1:1.316
1:1.3216

63.161
63.4386

86.1052
90.23

1 : 1.363
1:1.381

It would be natural to attempt to explain this pheno-
menon by the supposition, that the angle which a new
septum of the apical cell forms with the next older side
wall, bears a relation to the angle of divergence of the
frond arrangement, inasmuch as it equals the half of the
latter angle. The necessary result of this would be, that

* I considered it much better to calculate the angle of the apical surface
lrom the length of its sides than to measure it directly with the goniometer
as the former process gives a more certain result. The credibility of each
method depends upon the same circumstances as those upon which, in the
determination of phyllotaxis, the relative credibility of the results obtained by
the direct measurement of the angle of divergence and by the calculation of the
latter from the number of the turns, depends. The number of measurements
might easily have been increased, but it seemed advisable to exclude all the
cases in which the imperfect parallelism to the apical surface of the stem of
the section separating the outermost apex of the flat bud from the remaining
tissue, might have given rise to mistakes.

THE HIGHER CRYPTOGAMIA. 235

'in each mode of frond arrangement following upon the
| arrangement, such as •&, £ and so forth, the form of the
apical surface of the cell of the first degree would be that of
an isosceles triangle. Each cell of the second degree might
be treated as the primary mother-cell of a frond, to be pro-
duced by the further development of the cells derived from
the secondary cell. This supposition would however re-
quire that the four sided apical surface of each cell of the
second degree, should, immediately after its production, be
considerably wider on the hinder edge than on the fore
edge. The excess of the length of the hinder edge over
that of the fore edge would be determined by the difference
between the apical angle and one of the side angles of the
upper surface of the cell of the first degree. It would
necessarily bear the same proportion to the second youngest
side of the apical surface of the compound figure formed by
the cell of the first degree and the youngest cell of the
second degree, as the sine of the apical angle bears to that
of one of the side angles. Consequently each cell of the
second degree must, immediately after its production, be
wider at the hinder end than at the fore end to the following-
extent in each respective case, that is to say, — in the farrange-
ment to the extent of about the whole length of its front
wall and of the oldest wall of the apical cell which repre-
sents its prolongation, — in the I arrangement to the extent
of something more than the half (0'5412) of this length, —
in the T53 arrangement to the extent of about T70 (0*70081) of

the same.

Observation entirely upsets the above supposition. It is
true that in older cells of the second degree, especially in
those which are already several times divided, the outer side
wall normally diverges from the inner one. But the
younger the cells of the second degree which are subjected
to examination, the more nearly do their side walls approach
to parallelism, until at last it is manifest that the earliest
septa of the cell of the first degree appear exactly parallel
to the oldest side wall of the same cell (PI. XXVII, fig. 1).
It is plain from this that in point of fact the supple-
mentary expansion and the multiplication of the cells of
the second degree proceed step by step from back to front

236

HOFMKISTER, ON

(by which gradual advance the broken, sharply-angular suc-
cession of these cells is converted into a spiral) but that
there is no perceptible divergence of the newly formed septa
of the cell of the first degree from the oldest opposite side
wall of this mother-cell.

There is a second series of facts which militates not less
decidedly against the above assumption, viz., the occurrence,
although a rare one, of apical surfaces of cells of the first
degree which exhibit angles not corresponding with those
of the frond-arrangement. The following instances have
been observed, and they are the only ones obtained in a
long series of investigations : —

Length of

Length of

1

the oldest

the youngest

side wall of

side wall of

Relation of

the apical

the apical
cell.

the two.

cell.

Asp. spinulosum, w

arrangement,

Spiral

right

60.583

83.0116

1:1.37

" )> >>

33

33

33

56.3293

76.30S8

1:1.355

>> }> >j

33

33

left

52.7201

68.783

1 : 1.307

33 33 33

33

33

right

45.5017

52.4623

1 : 1.152

33 33 33

33

33

left

59.5518

61.0986

1 : 1.026

„ filix-mas, „

»>

13

right

55.427

73.9886

1:1.335

s

33 33 TTT

33

33

33

71.1528

88.1676

1 : 1.239

„ spinulosum, f

33

33

33

69.863S

75.7932

1:1.088

„ filix-mas, -£$

33

33

))

88.4254

85.074

1:0.961

>> 3> J>

33

>>

33

69.0904

63.161

1:0.913

In the greater number of these irregularly shaped cells
their size is very remarkable. In none of the foregoing
tables did the base of the triangle attain the length of
64 m. m. m., a length which is here often surpassed.0

But the measurements of those apical cells in which the
length of the oldest side-wall considerably exceeds that of the
youngest, are very instructive. Taken in connexion with the
fact, that in by far the greater number of instances the
angles of the apical cell correspond with the divergence of the
frond-arrangement, these phenomena indicate that after
each division the apical cell does not become enlarged
equally in all directions so as to attain the size which it
had before the division, but that the expansion which

THE HIGHER CRYPTOGAMIA. 237

ensues takes place, if not exclusively, at all events prin-
cipally, in a direction at right angles to the septum last
produced. This septum which, at the instant of one divi-
sion, forms one of the sides of the isosceles triangle repre-
sented by the upper surface of the cell of the first degree,
is, until the next division, far surpassed in longitudinal
growth by the two other side walls of the apical cell, so
that the latter then constitute the sides and the newly-
formed septum the base of the triangle. The new division
is produced by a septum which is parallel to the second
side wall of the apical cell, which side-wall at the time of
the preceding division was the longer one, and which in the
mean time has become elongated and displaced.

The diagram given in PL XXXII, fig. 5, of the mode of
succession of four such divisions of the apical cell of a bud
with the /a arrangement, will explain the above sugges-
tion.

The triangle enclosed by the lines 1, 2, 3, represents
the apical cell before the first of these divisions ; the line 4
represents the course of the dividing membrane. This
cell (which we will designate with the figure II until the
next division) now expands to the left : the line 4 now be-
comes the base of the triangle ; the line 1, increased by the
line ln becomes one side of the triangle, and the line 3,
displaced to 311 and lengthened, becomes the other side of
the triangle. The next division is represented by the
line 5. This line becomes the base of the upper surface
of the cell, which is enclosed by the lines 3n, 4, and 5, and
which expands again to the left. By this expansion the
line 3 becomes the line 3m, and the line 4 becomes 4m.
The line 6 represents the third division. The apical cell is
now first bounded by the lines 4, 5, 6. By a fresh expan-
sion of the cell the line 5 is increased by the line 51V, 4 is
shifted to 41V, 2 to 2IV, and 1 is extended to 1IV.

PI. XXXII, fig. 6, exhibits the somewhat complicated
mode of arrangement and displacement of the cells of the
second degree after three more such divisions of the apical
cell.

All the above facts can easily be brought under the one
point of view of the above supposition. The latter explains

238 H0FME1STER, ON

the frequency of the correspondence in form of the upper
surface of the cell of the first degree with the frond
arrangement, as well as the rarity of the deviations from
this form. Moreover, the observation confirms the conse-
quent backward curvature of the lines uniting the project-
ing angles (which are turned to the same side) of the dif-
ferent courses of the successive cells of the second degree
around the axis of the stem ; — which lines represent three
similar turns of the frond-spiral. The above opinion is
further supported by the fact, that the expansion and dis-
placement supposed to occur in the apical cell, must neces-
sarily follow from the enlargement and multiplication,
progressing gradually from the older to the younger ones,
of the cells of the second degree. The marginal angles
of the lateral surfaces of the cell of the first degree, must,
in the direction of the ascending spiral which represents the
course of the divisions, become more acute at the fore
edges, and more obtuse at the hinder ones, if — as observa-
tion proves — the multiplication of the older cells of the
second degree in the direction of a tangent to the stem is
more active than that of the youngest cells. In this process
the apical cell may be looked upon as to a certain extent
passive.

The supposition of a high degree of expansive and for-
mative power in the walls of the young cells of a portion
of a plant in process of development, is indispensable for the
purpose of explaining the change in the position and form
of the individual cells, which is caused by the growth of the
entire portion of the plant, and by the influence of the expan-
sion (and the multiplication of the older cells and masses of
cellular tissue) upon the younger ones, and conversely. In
the terminal bud of ferns expansion and multiplication of the
secondary cells, and of the groups of cells produced by their
divisions, advance in an ascending spiral from below up-
wards. In the neighbourhood of the apical cell this expan-
sion occurs at an early period (and is consequently more
advanced and productive of greater results) in the oldest
wall which forms the base of the upper surface of the cell, and
in the next oldest, whose margin forms the penultimate side
of that surface. The growth of the apical cell, which, between

THE HIGHER CRYPTOGAMIA. 239

each two divisions always increases to nearly the original
size, become especially active in the direction of the mar-
ginal angle formed by these two side- walls. This will
cause its form to vary more and more in the manner above
pointed out, until the relation between the angles required
by the hypothesis is attained. It is easy to imagine that
any excess of aperture is prevented by the proportion of
the rapidity of the progress of the multiplication of the older
secondary cells to that of the youngest.

In the course of the long inquiries leading to these results,
I met with only one isolated fact which militated against
the conclusions arrived at. I found the apical cell of a
terminal bud of Aspidium spinidosiim, the base of whose
upper surface measured 4T248 m.m.m., and each side
97*808 m.m.m. The stem, which had the left-handed
T| arrangement of the fronds, was growing at the edge of
a ditch, amongst a mass of briars, being half buried in the
earth, and directed downwards : the joints of the stem
were unusually elongated. It is probable that the plant was
in an abnormal, perhaps in a diseased condition.

The two-edged form of the apical cell, and the bilinear
arrangement of the fronds, of Pleris aquilina, have been
already observed upon. The same coincidence is always
met with (as far as present observations extend) in
Niphobolus rupestris and N. Lingua, in Polypodium punctu-
latum, P. cymatodes, and P. aureum, and very frequently
in P. vulyare and Dryopteris.

The determination of the cell-succession in the apical
region of the leaf-buds of phscnogamous plants is attended
with considerable difficulties. The minuteness of the ele-
mentary organs is the least obstacle ; a more formidable
one, especially in the Coniferse and Dicotyledons, is the
very early occurrence of rapid and vigorous multiplication
of the secondary cells of the flat end of the bud. It is not
always that the terminal cell of the bud can be ascertained
with certainty. Where however this was done the form of
this cell corresponded with the phyllotaxis ; it was two-
edo^ed in the grasses {Sccale cereale, Phray mites arundinacea)
and in species of Iris ; and often of the same shape in trees
with decussate leaves {Acer, Frawinus, Cupressus). Here

240

HOFMEISTER, ON

however cases occurred, though less frequently, of tri-
angular upper surfaces with a very acute apical angle.
These irregularities possibly depend upon the fact of the
occurrence in each internode of a gradual transposition, a
deviation of about 90°, of those septa of the apical cell of the
bud, which are turned towards the surfaces of the leaves.

Trees with imperfect 3-numeral phyllotaxis always ex-
hibited three-sided apical cells with one shorter edge. In
Robinia Pseudacacia (phyllotaxis |) the following measure-
ments occurred : —

The base of the triangle.

9.9288 m.m.m.
10.121
9.875

One of the sides.

15.4448 = 1 : 1.555
10.2936 = 1 : 1.689
15.9975 = 1 : 1.62

Mean

= 1 : 1.634

This result corresponds as nearly with the relation re-
quired by calculation, viz. 1 : 1*618, as could be expected,
considering the errors in measurement likely to arise from
the minuteness of the objects. Even if the first of the
above measurements may not be attributed to the dis-
placement of the apical cell between two divisions, it would
only be necessary to introduce a correction of about ^
millimeter in the first, and the same in the second (where
the proportion is too large), in order to make the observed
measurements correspond with the calculated ones.

The following are farther measurements of apical cells : —

—

Base.

Side.

Relation of
the two.

Pinus Abies, phyllotaxis A turned to

M.M.M.

M.M.M.

the right

13.79

18.7544

— 1 : 1.36

" » »

15.8509

21.5124

= 1 : 1.3566

» „ „ H turned to

the right ....

14.6174

20.4192

= 1 : 1.397

Pinus Balsamea, phyllotaxis -$i turned

to the right

13.8451

19.0302

= 1 : 1.375

» j) »

14.3416

19.488

= 1 : 1.359

» >> »

13.5422

18.4015

= 1 : 1.363

Zamia longifolia, phyllotaxis -^ turned

to the right

27.58

38.612

= 1 : 1.4

THE HIGHER CRYPTOGAMIA. 241

The first division — at right angles to the free outer sur-
face— of the cells of the second degree oiAspidium filix-mas
and A. spimdosum is produced sometimes by a septum
parallel to the front surface, i. e., the surface by which the
cell of the second degree is connected with the cell of the first
degree (PI. XXVII, tig. 2, PI. XXXII, fig. 4), and some-
times by a longitudinal septum meeting the front wall at an
angle of about 70° (PI. XXVII, fig. 1). In the former
case the second mode of division follows upon the first, in
the latter case the first mode of division follows upon the
second ; the final result is the same in both cases. The
further divisions of the cells of the terminal bud are subject
to not less stringent rules. The tendency to transform the
zigzag line of succession of the generations of cells resulting
from each cell of the second degree into an uniformly ascend-
ing spiral line, manifests itself especially in the frequent
occurrence of three-jointed groups of cells which originate
in the following manner — the septum produced in a cell of
the outer surface is parallel to no one of the side walls, but
cuts two of the side walls of the mother cell which form an
edge, in such manner that the latter is divided into a
smaller daughter-cell with a three-sided outer wall, and
a larger cell with a four-sided outer wall. The latter cell
is divided again by a septum almost at right angles to
the one last formed. Instead of one cell of the nth
degree there are now three : one of the ^+ith and two
of ^+2th degree.

The cell-succession of the terminal bud, and the form of
the terminal cell which is possibly the result not the cause
of such cell-succession, are manifestations of the same power
of growth, by wliich the arrangement of the fronds on the
axis is determined. After long extended and often re-
peated observations of the attendant circumstances, the
conclusion will not be premature, that the power by which
the form of the growing portions of plants is determined,
is manifested in the details of the cell-multiplication by so
much the less in proportion as the organs in question are
composed of a greater number of cells. The main direc-
tions in which the cell-multiplication takes place are fixed :
the number however and mode of succession of the cell-

16

242 HOFMEISTER, ON

divisions in these directions varies within rather wide
limits.*

The younger portions of the bud of Aspidium jilix-mas
are envelopecl in transparent mucilage as is usually the case
with all buds.f Owing to the very imperfect exclusion of
the outer air from the terminal bud of this fern, in which the
punctum vegetationis is only covered by the connivent
scales of the older parts, this mucilage is often partly dried
up, and forms a structureless membrane, granular on the
outside, covering the top of the bud ; precisely similar to
that which is seen on the youngest parts of the fronds of
Anthoceros.| In order to obtain a clear view of the top of
the bud it is necessary to remove this membrane, which is
a laborious and uncertain operation.

The small scales (whose development differs in no essen-
tial particulars from that of the similar organs in Nipho-
bolus rupestris to which we shall afterwards refer), make
their appearance on the terminal bud very far above the
point at Avhich the cellular increase of the stem in thickness
terminates, but never above the place of origin of the
youngest frond (PL XXVI, fig. 14; PL XXXII, fig. 4).
This holds good in Aspidium as well as in Pteris, Poly-
podium, &c. According to Nageli's definition of leaves
and hairs, § the scales would undoubtedly belong to the
former, as I also formerly assumed to be the case.|| On
the other hand a conclusive method of distinguishing

* This conclusion is the same as that which I arrived at on a former occa-
sion from observations on Isoetes (see vol. ii of the 'Abhandl. der K. Sachs.
Ges. d. Wiss.' p. 161). The statement there made, that all the septa — turned
in one of the three directions — of the apical cells of the three-furrowed IsoeteEe
are at right angles to a plane passing through that indentation of the stem
which is nearest to them, is too positive and general. Nevertheless the obser-
vations, the number of which was limited by the paucity of the materials,
certainly show, that all the septa seen were turned towards one of the indenta-
tions ; no one of them was turned towards the space intermediate between two
indentations. This fact may have some connexion with the high ratios of the
numbers representing the phyllotaxis of those species of Isoetes.

f See 'Vergl. Unters./ p. 82, note.

% See 'Vergl. Unters./ PI. i, figs. 8, 9.

§ * Zeitschr. f. Wiss. Botanik.,' Heft 3, 4, p. 185. The leaf is formed on the
outside at the top of the stem, close under the apical cell, before the growth in

thickness by peripheral cell-formation is ended The hair,

&c, is formed on the outside on an epidermal cell by growth of the latter after
the termination of the peripheral cell-formation

|| 'Vergl. Unters.,' p. 87.

THE HIGHER CRYPTOGAMIA. 243

between the two is arrived at, if the difference between
hairs and leaves is sought for in the facts that the youngest
hairs are never seen below the first visible rudiments of the
leaves, and that leaf-formation on the axis always precedes
the formation of hairs. By trusting to these characters the
observer will never be in doubt, in any case where the axis
of the plant exhibits both these forms of appendicular
organs. The scales of ferns therefore, as well as the hairs in
the buds of mosses and liverworts, fall under the definition
of hairs, and the fronds consequently under that of leaves.*

The formation of a frond commences thus — one of the
superficial cells of the terminal bud, distant from the next
older frond by the angle of divergence of the frond- arrange-
ment increases in size, and becomes arched outwards in a
papillate manner (PI. XXVII, fig. 4; PL XXXII, fig. 4),
In this cell there commences a series of divisions which are
repeated continually in the apical cell by means of septa
turned to the right and left towards the future margins
of the frond. The secondary cells multiply in nil three
directions more vigorously on the hind surface of the
frond, so that the latter is converted into a somewhat
slender cone bent over towards the fore part. Septa are
now produced in the apical cell, turned towards the fore
and hind surfaces of the frond, and alternating with others
turned towards the lateral margins. The further formation
of the frond, the development of its blade, takes place in
the manner pointed out in Pteris aquilina.

In the mature plant of Aspidium jilix-mas roots (as we
have already said) are no longer formed on the stem itself,
but exclusively on the protuberant swollen portion of the

* Two of the main grounds formerly adduced to prove that the scales were
of the nature of leaves, and the fronds of the nature of branches, have been
set aside. Kunze's statement, that the delicate bodies, resembling the fronds
of Trichomanes, found at the base of the stipes of Hemitelia capensis are
transformed scales, is erroneous, as has been already observed. They have
nothing in common with scales as may be seen at once by the examination
even of a dead stem. The course of the vascular bundle within them is con-
clusive to show that they have been formed in the earliest stage of the frond,
even before the commencement of the formation of the blade of the latter. I
have latterly arrived at a very clear view of the growth in the OphioglosseEe. I
formerly thought that it must be considered to consist of a successive series of
adventitious buds. I now find that the Ophioglossese agree essentially with the
Polypodiacese.

244- HOFMEISTER, ON

stipes. They originate here from the vascular bundles
which run on the hind side of the stipes, parallel to the
longitudinal ridges of the latter. Usually two roots are
formed on each stipes. Every longitudinal and transverse
section of the root-cell of the first degree appears triangular.
Its form is that of a low three-sided pyramid. It divides
by means of a concave septum turned towards its slightly
convex basal surface, and by this means lenticular cells are
formed, each of which becomes the mother-cell of two of
the cap-shaped cellular layers of the root-cap. The len-
ticular cell divides by longitudinal septa into four cells
standing cross-wise (PL XXVII, fig. 10), after which trans-
verse septa are formed. In the middle of the circular
cellular layer, the further division by longitudinal septa
occurs more rapidly and more frequently than at the edges,
by which means the cellular surface assumes its cap-like
shape. Between the older of these cellular layers, whose
outer walls become very much thickened, intercellular
spaces filled with air make their appearance ; this is the
first commencement of the falling off of the cellular layers
of the root-cap, which decay by degrees from the outside.
Each division which is produced by means of a concave
septum turned towards the basal surface of the cell of the
first degree, is followed by three divisions of the latter, by
means of septa successively parallel to each of its three
lateral surfaces. The three cells of the second degree thus
formed, and which stand in a triangle, divide by means of
longitudinal and transverse septa, the division being more
active in that portion of them which is more distant from
the longitudinal axis of the root. The short-celled tissue
here formed becomes the cortical layer, whose early growth
is afterwards overtaken by the rapid longitudinal expansion
of the axile cellular tissue of the root during the transfor-
mation of the latter into the central vascular bundle *

It is only in very rare instances that the terminal bud of
the stem o>i Aspidium filix-mas divides by true forking of the

* In consequence of my having examined seetions which were not truly
axile, I was led to assume that the lenticular cells of the interior of the root of
Equisetum variegatum (' Vergl. Unters.,' pi. xviii, fig. 3), as well as the primary
cells of one of the layers of the root-cap, were root-cells of the first degree.

THE HIGHER CRYPTOGAMIA. 245

pmictum vegetationis. The multiplication of shoots by
means of adventitious buds is proportionably more frequent.
These buds always originate on the back of the stipes, at
the place where the protuberant swelling of the latter passes
off into the more slender upper portion. After the removal
from the stipes of the thick covering of scales, the earliest
conditions of the adventitious buds mav be seen in the form
oi a disk surrounded by an annular furrow and having a
slight protuberance at its middle point which represents the
apex of the new axis in process of formation. Somewhat
later, other protuberances, being the rudiments of fronds,
are seen, arranged in a circle round the central one (PI.
XXVII, fig. 5). Whilst on the mother- plant the new
shoot begins to send forth roots independently (PI. XXVII,
fig. 6). The vascular bundles which pass to it from the
vascular bundles of the frond on which it is produced,
unite at its place of attachment so as to form a closed
ring from which their distribution in knots answering to
the insertions of the fronds commences (PI. XXVII, fig. 7).
Such adventitious buds are formed on vigorous plants in
fertile habitats at about every twelfth frond, and much more
frequently in plants growing in dry situations.*

Aspidium spinidosum comports itself in all its parts like
Aspidium filix-mas. The adventitious buds are here met
with very near the base of the stipes. The scales bear at
their apices, and frequently also on the teeth of the margin,
very swollen, oval, or pear-shaped cells with mucilaginous
contents ; a phenomenon which is also seen in Aspidium
Oreopteris, Asplenium filix-femina, Struthiopteris germanica
and other ferns.

Asplenium filix-femina; Asplenium Bellangeri; Struthiop-
teris germanica ; JVep/trolepis imdulata ; Nephrolepis splen-
dens. — The above-named ferns agree entirely in the principal
features of vegetation, viz., in the form and mode of multi-
plication of the cells of the terminal bud ; in the position of
the frond-cells of the first degree with regard to the apical
cell of the terminal bud ; and in the arrangement of the

* It is probable that Schleiden had these buds in view when he spoke of
this fern as having axillary buds (' Grundziige ' 2 Aufi., vol. ii, p. 87), which
in Aspidium filix-mas, as in all European ferns, are absolutely unknown.

246 HOFMEISTER, ON

vascular bundles in the stem. Asplenium filix-femina is
distinguishable by the more slender form of the terminal
bud, the growth of which in thickness terminates at the
fourth set of cells, (reckoning downwards and sideways from
the apical cell), the produce of one of the cells of the second
degree, so that the frond-less apex of the stem is elevated
considerably above the earliest rudiments of the fronds
(PI. XXXIII, fig. 2). A further peculiarity of this plant is
that only one vascular bundle enters each stipes from the
upper angle of each knot of vascular bundles. For a con-
siderable distance this bundle is simple ; it then divides
into two, and further up into several strings. The status
which in Aspidium jilix-mas only occurs whilst the plant is
young, that is to say only in the one year old plant, is main-
tained here during its whole life. Underneath the place
where the vascular bundle of the stipes exhibits its first
ramification, one root is normally produced ; each frond
has only one, which is developed in a plane passing through
the median line of the frond. This circumstance greatly
facilitates the investigation of the earliest stages. In well-
made longitudinal sections, close outside the rudimentary
vascular bundle of the frond, there may be seen the primary
cell of the appurtenant root, by the multiplication of which in
the manner pointed out in Aspidium flix-mas, the root-cap
and the permanent cylindrical portion of the root are pro-
duced (PI. XXXIII, figs. 4, 5). The tissue of both halves
of the growing root, as well as the cells of the root-cap, are,
whilst in this early state, in intimate parenchymatal con-
nexion with the cortical cells of the stipes. Afterwards,
shortly before breaking forth from the hind surface of the
stipes, the boundary between the root-cap and the cells be-
fore it becomes sharply defined (PI. XXXIII, fig. 6) with-
out however any rupture of the tissue, or the appearance of
any inter-cellular space. The few cellular layers of the
stipes anterior to the apex of the young root, are gradually
displaced and dissolved, not broken through; the cuff-
like margin, which is formed from the cellular tissue of the
mother-portion of the plant, and which is so remarkable on
the adventitious roots of many Monocotyledons, is wanting
here.

THE HIGHER CRYPTOGAMIA. 247

Adventitious buds are very rare in Asplenium filicc-
femhia ; it would seem that they never occur when the
plant is growing naturally. However at the base of the
stipes of a frond which had been torn off and kept for some
time in a closed bottle in moist air, I saw adventitious buds
produced underneath the place of attachment of the roots
(PL XXXIII, fig. 1). On the other hand the forking of
the apex of the stem by division of the frond-less terminal
bud is in this fern quite a normal process ; it is the usual
asexual mode of multiplication of the plant which it would
seem occurs at tolerably regular intervals. The observer
will seldom fail to find the bifurcation of the stem in old
plants ; specimens often occur with from four to nine
heads.

In Struthiopteris germanica * the formation of numerous
adventitious shoots is added to the other peculiarities already
mentioned.! As in Aspidium spinulosum, they originate
on the outside, at the base of the stipes, close above its in-
sertion into the stem. The first commencement of their
formation occurs unusually early, long before that of the
blade of the frond. In their first development they are
directed obliquely downwards (PI. XXXIII, figs. 7, 8).

The copious production of adventitious buds on all parts,
even on the ramification of the blade of the frond, is very
remarkable in Asplenium Bellangeri. The mode of develop-
ment is essentially the same as in Aspidium filix-mas.
Here also the new shoots do not originate in the interior of
the tissue of that portion of the plant which produces them,
but outside, on its outer surface.

It is well known that the species of Nephrolepis send
forth long thin runners, whose ends, in Nephrolepis undu-
lata and N. tuberosa, swell into knobs, f The stolons
originate from adventitious buds, which are produced
apparently on the stem, at that part of the base of the
frond which amalgamates with, and forms a bark to the
stem (PI. XXXIV, fig. 3). The runners are one third of a
line thick, and sparingly clothed with pale yellow scales ;

* On the distribution of the vascular bundles, see Schacht, ' Pflanzenzelle,'
PI. xv, fig. 3—6.

f See Braun, ' Verjiingung,' p\ 115.
+ Kunze, <Bot. Zeit.,' 1849, p. 881.

248 HOFMEISTER, ON

they root here and there, and are traversed by a vascular
bundle. The apical cell of the terminal bud is always
two-sided in N. undulata. On the thicker stolons of
N. splendens it appears to be frequently three-sided. In
N. undulata it first assumes this form when the apex of the
runner begins to form a knob. Within the swelling mass
of parenchyma the central vascular bundle, which has
hitherto been simple, becomes branched (PL XXXIV,
fig. 1). The bundles are henceforth arranged in a circle
concentrical with the periphery of the knob.

As far as my observations extend, the vegetation of
the terminal bud ceases with the complete formation of
the knob, which is about an inch long.* The arrange-
ment of the cells admits of the observation of their mode of
cell-multiplication, if followed out in the same manner as
in the end of the stem of Aspidium filix-mas. The con-
tents of the cells, as well as those of the numerous rudi-
ments of withering scales by which they are surrounded,
become transparent. The knob sends forth fresh adventiti-
ous buds, which originate in numbers on its lateral surfaces
(PI. XXXIV, fig. 2). Soon after the development of these
shoots the knob decays.

Polypodium, Niphobohis. — The species of Niphobolus,
which I have examined {N. rupesiris and N. chinensis), as
well as several foreign species of Polypodium (aureum,puncta-
tum, cymatodes), all exhibited the two-edged form of apical
cell answering to the bi-linear frond-arrangement. In Poly-
podium vulgare it was otherwise. Here the terminal bud,
when viewed from above, exhibits sometimes the form of the
cell of the first degree and the arrangement of its next deriva-
tives as in Aspidium filix-mas (PI. XXXIV, fig. G) ; some-
times (and most frequently) the two-edged form of the upper
surface of the apical cell (PI. XXXIV, fig. 5) ; sometimes
forms which may be looked upon as intermediate between
the two, inasmuch as the free outer wall of the cell of the
first degree has the shape of a triangle, whose sides are
more than three times the length of the base. Deviations
from the typical bi-linear frond-arrangement are not un-

* This is opposed to Kunze's statement. He describes the further develop-
ment of the apex of the bud, 1. c, p. 882.

THE HIGHER CRYPTOGAMTA. 249

common in this species. They occur very frequently in
plants which grow in places having a comparatively small
amount of moisture, as is the case usually in an open
plain. The frond-arrangement oscillates unsteadily be-
tween \ and \. Similar deviations occur in Polypodium
Dryopteris.

The walls, by whose appearance in the first cell of the
rudimentary frond the formation of the stipes commences,
are radial, not tangential to the axis of the stem (PI.
XXXIV, fig. 4), agreeing in this respect with those of
Aspidium jilix-mas, and differing from those of Pteris
aquilina. At the slender ends of the stems of Nipliobohs
rupestris and N. splendens, the development of the scales
may be very conveniently traced. This development takes
place at some little distance underneath the apical cell of
the stem. The formation of the scales begins at a distance
of eight cells from the top, reckoning downwards, by the
formation of a papillate protuberance of the free outer wall
of a cell of the circumference (PL XXXII, fig. 9). The pro-
tuberance is soon cut off from the original cell-cavity by a
transverse septum. The appearance of a new transverse
septum then divides the cell, which is already much flattened
laterally, into an upper and a lower cell (PI. XXXII, fig. 10).
Repeated transverse divisions, not only of the apical cell,
but also of the interstitial cells (PI. XXXII, figs. 11, 12),
transform the rudiment of the frond into a short series of
low cells with an elliptical basal surface. The phenomena
which become visible from these divisions, and especially
the gradual dissolution of the primary nucleus of the divid-
ing cell and the appearance of two new nuclei in its place,
are precisely the same as those which are observed in the
multiplication of the cells of the hairs of phaenogamous
plants (PL XXXII, fig 11).

The cells of the lower portion of the young frond now
divide by longitudinal septa which coincide with the me-
dian line of the frond. These longitudinal septa are per-
pendicular to the surface of the frond, like the walls of
almost all the cells which take part in the formation of the
scales of ferns. The division progresses from the base
of the frond towards its apex, extending in Mp/todoius ru-

250 HOFMEISTER, ON

pestris to about the sixth, in TV! splendens as far as the
third cell from the apex, reckoning backwards. The upper-
most cells of the frond, those into which the above division
does not extend, now expand considerably lengthwise,
the expansion commences with the apical cell and the
others follow step by step (PI. XXXII, figs. 13, 14). The
termination of the multiplication of these cells is mani-
fested by the thickening of their walls, and by their con-
tents becoming transparent. On the other hand a partial,
very considerable multiplication, ensues in the remaining
cells of the frond. It is most considerable in the cells at
the base, where the divisions by means of septa at right
angles to the longitudinal axis of the frond are most fre-
quently repeated, alternating with divisions parallel to
such axis. The activity of the cell-multiplication dimi-
nishes continuously towards the apex of the frond. The
divisions first cease in the cells of the upper half of the
frond, which become elongated at the earliest period and to
the greatest extent. The division of the cells of the
frond by means of septa parallel to the longitudinal axis,
appears not to be contemporaneous ; it is repeated oftener,
and "extends nearer to the apex of the frond in one longitu-
dinal moiety of the frond than in the other (PL XXXIII,
fig. 8).

Owing to the gradual increase in breadth of the base of the
frond, its cells in Niphobolus rupestris, Nephrolepis splendens,
and Poli/podium aureum, do not amalgamate with the cells
of the circumference of the stem with which they are in
contact. The place of attachment of the frond does not
become wider, and moreover consists, even when the frond
is perfected, of only two cells, which have been produced
by the division by means of a longitudinal septum of the
undermost cell of the rudiment of the frond. The cells
of the free margin of the base of the frond multiply actively
in many species (as for instance in Niphobolus rupestris
and N. splendens), through division by means of septa
parallel to a tangent to the circumference; those cells
which adjoin the place of attachment of the frond and the
angle of the lateral margins multiplying less actively than
those between them. The base of the frond thus becomes

THE HIGHER CllYPTOGAMIA. 2.")1

heart-shaped. The cells of the place of attachment, and
often also those near it, divide, when the frond is almost
perfect, by means of septa parallel to the surface of the
frond (PL XXXIV, fig. 7). The cells of the lateral margins
of the leaf often grow into delicate little teeth, which are
usually curved backwards.

Scales which run through all the stages of development
here represented are found not only on the principal axis
of the plant but also on the lower portion of the frond. In
the greater number of ferns the bases of the fronds exhibit
scales at least in their youth. The arrangement of the
scales both on the principal axes and on the fronds is
governed by well-defined rules.* The reason why the
arrangement is often undistinguishable on the fronds is
that after the last important longitudinal expansion of the
stipes individual scales fall off abnormally much earlier than
the neighbouring ones.

In the earliest stages of Polypodium vulgare scales are
found whose almost circular form indicates the tendencv to
assume the shape of a shield which is ultimately arrived at
by the exuberant growth of the hinder margin, in which
growth those daughter-cells take part which are derived
from the primary cell, which after numerous divisions by
means of longitudinal septa has become the attachment-ccl !
(PL XXXIV, fig. 7).

The separation of the vascular bundles from the rest of
the tissue of the stem, and the formation of roots from
them, take place as in Aspidium and Pteris. In Poly-
podium vulgare, as in Polypodium aureum, the vascular bun-
dles run off into a cylindrical annular net of meshes, which
have no immediate relation to the insertions of the fronds, f

Platycerium Alcicome. — The first frond of the germ-
plant is erect and fleshy, having the shape of a spatula,
and being slightly bent over behind. It is clothed with
the stellate hairs characteristic of the plant, and has but
few scales. The latter are more abundant on the young

* For instance, on the principal axis and fronds of Nipkobolus chinensis the
arrangement is ft. The regularity of the arrangement is beautifully shown on
the procumbent stem of Polypodium aureum by the little depressions, of which
each one indicates the place wlicre a scale has been attached.

f See V. Mohl, 'Vermischte Schriften,' p. 115.

252 HOPMETSTER, ON

stem, and are remarkable for their rapid development,
especially in thickness, even in the early youth of the
plant. The fronds which follow the first frond differ
remarkably in form, direction, and structure. Their
outline is circular or reniform ; they are developed in
a horizontal direction, bending backwards and downwards
to such an extent from the point of attachment, that they
touch the base of the plant. Their thickness far exceeds
that of the upright frond ; their vascular bundles lie, not in
one, but in two planes parallel to the surfaces of the frond.
These bundles form two many-meshed nets, one close under
the upper side, and the other immediately above the lower
side of the frond ; the two net-works are united in many
places by frequent ramifications which pass through the
mass of the frond in a transverse direction.

When the plant has attained a certain amount of vigour,
erect fronds are again formed, which hang over gracefully,
and exhibit slightly spreading forks upon which spo-
rangia sometimes appear. After six or eight such erect
fronds have been produced, a pair of simple fronds is de-
veloped, one on the right and the other on the left of the
stem. These latter fronds curve downwards. All the
fronds, as well the thick flat recurved ones as also those
which are slender and erect, are arranged accurately in two
lines ; this is seen clearly by cutting through the fronds as
far back as the primary place of attachment. The direction
of the frond-arrangement, judged by reference to the mode
of succession of two neighbouring flat fronds, is sometimes
to the right and sometimes to the left. A bud is usually
formed deep down on the hinder side of the stipes of each
of the erect fronds. This bud, when laid bare by the re-
moval of the flat frond which forms a thick covering over
it, becomes developed into an independent plant.

It is not difficult to conjecture the part which the thick
recurved fronds play in the economy of the plant. They
prevent the drying up of the place of growth. The thick
covering which they form causes that portion of the bark
of the trunk of the tree upon which the fern grows, to be
retentive of moisture. Those species of the same genus
whose fronds spread over the surface of the ground, — thus

THE HIGHER CRYPTOGAMIA. 253

forming a wide covering over the places of attachment of
the older fronds and the ground beneath as in Flatyoerium
gr ancle, — are entirely devoid of the irregularly-shaped,
fleshy, recurved frond.

The vascular bundles of the horizontal stem are arranged
in a simple circle (PL XXXIV, figs. 8, 9) ; they form on
the upper side a polygonal net, and on the under side a
net with very narrow, parallel meshes. The arrangement
of the meshes in both nets is shown in PL XXXIV, figs.
10, 11. The vascular bundles pass to the fronds from
the angles of the meshes of the upper side. These bun-
dles anastomose frequently in the cortical layer of the upper
side of the stem. The vascular bundles of the roots originate
at the upper and lower terminal points of the narrow
meshes of the under side of the stem, the roots themselves
being arranged in transverse rows. Roots very frequently
penetrate into the substance of the decayed flat fronds,
where they ramify considerably.

The cortical layer of cellular tissue which surrounds the
central vascular bundle of the root, exhibits an anatomical
peculiarity, having a remarkable analogy with what is seen
in the epiphytal Orchids and the Aroidese. The walls of
its cells, which become brown at an early period, are
thickened by a net-work of filaments. Narrow flat de-
pressions are seen between the very delicate threads of the
net (PL XXXIV, figs. 12, 12J). The outermost cellular
layer of the root of Platycerium, from which rootlets are
emitted, has the depressions, but not the reticulate threads.

The apical cell of the end of the stem of Platycerium
alcicorne is two-edged, having the form of a strongly-com-
pressed cone. The arrangement of the surrounding cells
discloses the fact that the multiplication of the cells of the
terminal bud is brought about by the continuously repeated
formation in the cell of the first degree of septa inclined in
two opposite directions. A parabolical line drawn through
the middle point of the places of insertion of all the younger
fronds, cuts the upper surface of the apical cell of the stem,
not in its shortest but in its longest diameter. The top
cells of the young fronds have their edges, and not their
surfaces, tinned towards the ends of the stem, whose apical

251 HOFMEISTER, ON

cell turns its own edges towards them. These facts are
directly contrary to what occurs in Pteris aquilifia, but on
the other hand they agree with what takes place in the
Polypodieae.

Marattia Cicutafolia* — The flat terminal bud of this
fern exhibits, when viewed from above, a three-sided apical
cell as in Jspidiuvi filix-mas. Longitudinal sections show
a very oblique arrangement of the side walls of the apical
cell and of the neighbouring cells. The rudiments of the
young fronds surround the flat conical end of the stem in
a spiral. The latest formed have the appearance of sharply
conical protuberances of cellular tissue flattened in front,
hardly distinguishable from the first rudiments of the fronds
of the larger Polypodiaceae.

In consequence of its increased longitudinal growth the
top of the young frond bends over in front. During this
process the stipula makes its appearance, in the first in-
stance at the fore surface of the young frond, in the shape
of a transverse protuberance (PL XXXIII, fig. 11). Shortly
afterwards a membranous cellular mass grows in a forward
direction out of each of the lateral margins of the rudiments
of the frond. Those surfaces of the two cellular masses
which are turned towards the protuberance of the fore-side,
amalgamate with the side margins of the latter (PI.
XXXIII, figs. 11, 12). The fore margins of the two
lateral lobes of the stipula remain free. In consequence of
their rapid further development they almost entirely en-
velope the younger portions of the stem-bud. In the
mean time the upper margins of the two lateral portions of
the stipula grow rapidly and vigorously upwards and back-

* De Vriese and Hartings Monograph of the Marattiaceae (Leyde et Dussel-
dorf, 1S53, pp. 49 and 51) contains statements as to the development of the
fronds of the Marattiaceae, which, if correct, show that the process is very
peculiar. It is there said, " The formation of each frond is preceded by that
of its Perula. ... It covers even the younger frouds partially. . . .
The cellular protuberance, in the form of which the younger frond makes its
appearance laterally near the terminal bud, consists in Angiopteris originally of
cells of equal size, and of equal capacity for multiplication. The outer cells
grow and multiply more rapidly, in consequence of which they separate from
the inner ones. The former constitutes the membranous portion of the Perula,
the latter that of the fronds." My observations on Marattia cicuttrfolia, from
which in this respect Angiopteris certainly does not differ, lead to entirely
different conclusions.

THE HIGHER CRYPTOGAMIA. 255

wards. They assume a cap-like form, and laying hold
of one another they envelope the apex of the rudiments of
the frond, which now for the first time slowly elongates
itself (PL XXXIII, figs. 15-19). Thus the rudimentary
Perula is formed in all its parts, but nevertheless as an
organic closed veil: its principal portion, viz., the two
membranous lobes which enclose the involute frond, con-
sists of two entirely distinct moieties overlapping one
another and leaving a wide opening at the place where
they impinge upon that part of the stipula which has origi-
nated from the fore surface of the rudiment of the frond
(PL XXXIII, fig. 19). By further development this trans-
verse portion of the stipula becomes divided at the upper
margin into two cellular surfaces, one of which is bent
backwards over the involute special frond, the other for-
wards over the rudiments of the younger fronds. By fur-
ther advance in growth all the parts of the stipula, especially
the basal portions, are developed to a great degree, so as
to form a tissue of considerable extent, of a dark red colour
on the outside and rose red within, and traversed by an
intricate complication of numerous vascular bundles and
passages containing gummy matter. The cells of this
tissue abound with large starch-grains. Even now, how-
ever, no amalgamation takes place anywhere between the
hitherto distinct portions of the stipula.

The development of the scales and roots of Marattia
differs in no material respect from that of the Polypodiacese.
The root-cell of the first degree appears three-sided both in
a longitudinal and in a transverse section of the root.

It is generally known amongst gardeners that fragments
of the fleshy adventitious fronds of the Marattiacese can be
used to produce new individuals. In Marattia cicutafolia
this mode of reproduction may be practised with exceeding
facility. The stipules, even of the most slender fronds, of
specimens grown in the same manner only a few months pre-
viously, may be employed for the experiment. If these
stipules be cut into pieces about half a square inch in size,
and simply placed in a stoppered bottle, adventitious buds,
produced at some of the numerous vascular bundles, will be
seen in ten or twelve weeks to break through the bark of

256 HOFMEISTER, ON

the fragments of the stipules. The first fronds of these
shoots have no lamina ; they are entirely stipulseform.

Development of the fruit and spores. — Although
much variety exists in the process of formation of those
organs of ferns which surround and cover the sori, ne-
vertheless the development of the capsules of the Poly-
podiacese exhibits, as far as present observations extend,
a marked uniformity. At the place of attachment of
the sorus the rudiments of the capsules are developed
(contemporaneously with the appearance of the indusium
where the latter is present), under the form of short multi-
cellular hairs. The terminal cell of each swells to a globular
form, and, by the effect of a series of cell-divisions, assumes
the form of a body consisting of a single central cell and
a peripheral cellular layer. The central cell is the primary
mother-cell of the spores. By division in all three direc-
tions of space it is transformed into a globular mass of
polyhedral cells — the spore-mother-cells— the walls of which
become somewhat thickened. Whilst the internal cavity of
the young sporangium becomes enlarged by the expansion
of the peripheral layer, the walls of the spore-mother-cells
swell, and the latter become disconnected, and assume a
globular form. They then divide into four special -mother-
cells, which in certain species are situated at the angles
of a tetrahedron, in others are arranged in a decus-
sate manner. A spore is formed in each of these
special mother-cells. The membrane of the primary
mother-cell is still existent at the time of the commence-
ment of the individualization of the spore-mother-cells, and
can be detached from the peripheral cellular layer.* This
development of the capsule has been observed by Schacht,

* Schacht, 'Bot. Zeit.,' 1S49, figs. 6, 7. The membrane of the primary
mother-cell, like those of the mother-cells, is somewhat distended; the
latter appear to be suspended freely in the former. Schacht was thus led to
assume that the mother-cells originated by free cell-formation in the primary
mother-cell (1. c., p. 544). Schacht's statement that the nucleus of each
primary mother-cell separates by division into four secondary nuclei, is not
confirmed by the observations which 1 have made upon Asplenium filix-femina
and Cy stopfer is f raff ills. In the former I found at first two secondary nuclei in
the place of the primary one, and afterwards four tertiary ones in the place of
the secondary ones. It appeared to me that here also the dissolution of the
primary nucleus of the mother-cell preceded the formation of the nuclei in
daughter-cells.

THE HIGHER CRYPTOGAMIA. 257

in Pteris serrtdata, Aspleninum Petrarice, and Scolopendrium
officinarum ; and by myself in JsjjI. JUioj-femlna, and
Cystopteris fragilis. H. v. Mohl, in 1833, described
the development of the spores in special-mother-cells
(four being contained in each mother-cell), whose mem-
branes possess a remarkable power of distension (see
'Flora,' 1833, B. i- ' Vermisclite Schriften,' p. 69). In
the families of ferns other than the Polypodiaceae, few ob-
servations have been made. I may remark here, that I
have clearly seen a single central cell in very young
sporangia of Osmunda regalis. In this respect, therefore,
ferns seem to agree with the rest of the vascular crypto-
gams, viz., that a single cell situated in the interior of the
young sporangium represents the primary mother-cell of all
the spores.

Historical Beview. — The reproduction of ferns by means
of spores was first pointed out by Morison, who states (' His-
toria plantarum,' Oxford, 1699, iii, p. 55) that after sowing
the spores of Scolojjendrium officinariim upon moist ground in
the shade, he obtained in the following year numberless little
plants of the same species, with delicate mid at first
roundish leaves. Ehrhart first made known with certainty
that the production of the perfect fern is preceded by the
development of a deeply two-lobed leaf-like body, upon
the under side of which, between the indentations and the
hinder end, the perfect fern is attached (' Beitrage/ iii,
Hanover, 17S8, p. 75). For the first accurate micro-
scopical investigations of the germination of fern-spores we
are indebted to Kaulfuss, who clearly and accurately
described the rupture of the outer spore-membrane, the
protrusion of the inner one, and the development of the
prothallium (( Das Wesen derFarrn-krauter,' Halle, 1827,
p. 61). The sexual organs of the prothallium entirely
escaped his observation, as well as the enclosure of the
young embryo in the tissue of the prothallium. The dis-
covery of this fact is due to Bischoff (' Handb. botan. Tcr-
minologie,' b. ii, Niirnberg, 1842, p. 640), who states that
a wart-like excrescence originates on the back of the pro-
thallium underneath its indentation, and that out of this
excrescence the first frond breaks forth in an upward

17

258 HOFMEISTER, ON

direction and the first root downwards, the latter being
surrounded at its base by the ruptured membrane of the
cellular "protuberance, as by a sheath. Upon the plate ex-
planatory of this process (1. c, t. 41, fig. 2385) an empty
antheridium is shown upon the prothallium, without how-
ever any mention of this organ being made in the text.
Two years afterwards Nageli published the discovery of the
antheridia and spermatozoa of the ferns (c Zeitschr. f.
wissensch. Bot./ Zurich, 1844, p. 168). He describes
the origin of the antheridium, of the mother-cells of the
spermatozoa, and of the spermatozoa themselves, essentially
in conformity with the account given in the preceding
pages ; he brings clearly forward the similarity of the an-
theridia of the ferns with those of the Muscinese and asserts
that the antheridia are very probably the male organs,
although it remained almost inexplicable to him in what
relation they could stand to the impregnation, which he
considered only to affect the spores. It is beyond ques-
tion that Nageli also observed the archegonia of ferns, but
misunderstood them : they are the organs which he describes
and figures (1. c, p. 171, t. iv,fig. 11 — 15) as many-jointed
antheridia. The real nature of the archegonia was first
correctly ascertained by Count Leszyc-Suminski (' Zur Ent-
wickelungs-geschichte der Farrn-krauter,' Berlin, 1848).
He pointed out (1. o, p. 13) that the rudiments of the frond-
bearing plant always appeared on the underside of one of
the archegonia, inside a cavity sunk in the tissue of the
cushion of the prothallium, and he assumed that in order
to excite the development of this embryo, the entrance of
one or more of the spermatozoa was necessary. He ob-
served the cilia of the spermatozoa, but did not figure them
quite accurately. Suminski's correct conclusions were
arrived at by observations which were to a great extent
erroneous. He believed that the archegoniuni in its
youngest condition, and before its neck protruded above
the surface of the prothallium, was open at its apex ; and
that at this period the entrance of the spermatozoon into the
central cell took place, He called the latter the cavity of
the germinal vesicle and its nucleus the germinal vesicle
itself. He considered that the longitudinal development

THE HIGHER CRYPTOGAMIA. 259

of the neck of the archegoniuni and the closing of its mouth
did not take place until after the entrance of the sperma-
tozoa. According to his view one of those spermatozoa
which had first effected an entrance into the archegoniuni
then penetrated with its pointed end into the embryo-sac
which in the mean time had become multicellular; the
pointed end then became swollen and converted into a
spherical cell which gradually displaced the tissue of the
embryo-sac, formed new cells in its interior, and thus con-
stituted the embryo. He thought that the spermatozoa
which had entered the archegoniuni at an early period,
and which had not aided in the formation of the embryo
but had reached the canal of the neck, were there trans-
formed into the worm-shaped masses which I have pointed
out as the product of the transformation of the cells of the
axile string of the neck of the archegoniuni. From the
erroneous notion entertained by Suminski as to the de-
velopment of the archegoniuni, it is quite clear that his
observations upon the entrance of the spermatozoa into the
central cell must be founded on a misconception, and that
he never really saw the spermatozoa enter the archegoniuni
at all. His idea of the formation of an endosperm in the
embryo-sac is founded upon an incorrect arrangement of the
different stages of development which he observed; the
body which he designates as endosperm, as " multicellular
parenchyma filling the embryo- sac," is in fact the young
embryo. L. Suminski first observed the cilia of the fore-
end of the spermatozoa, but did not draw them quite cor-
rectly (1. c.j t. ii, figs. 20, 21). Thuret gave the first
accurate figures of them (' Ann. d. Sc. Nat./ 3rd ser., vol.
xi, p. 5). A succession of works by other observers fol-
lowed quickly upon the publication of Leszyc-Sumin ski's
treatise. First came Wigand in the ' Bot, Zeitung/ for
1849. He disputed most of the statements of his prede-
cessor, even those which were quite accurate, such as the
constant occurrence of the cavity (of the central cell)
beneath the free portion of the archegoniuni (1. c, p. 78) ;
the regularity of the pressure of the neck of the arche-
goniuni upon that layer of the tissue of the prothallium
which covers the enclosed young embryo (1. c, p. 77, 106) ;

260 HOFMEISTER, ON

the normal concealment of the young embryo in the tissue
of the prothallium (1. c, p. 106), and even the possibility
of the access of the spermatozoa to the archegonia (1. c,
p. 78). On the other hand in the ' Bot. Zeitung,' for
1849, p. 796, I have given my opinion confirmatory of
the principal point in L. Suminski's statements, viz., the
regular development of a young plant in the interior of one
of the organs called Ovula by L. Suminski. I added that
the parting asunder of the four longitudinal rows of cells
which form the neck of the archegonimn, is the cause of
the opening of the passage which leads to the large cell at
the bottom of the female organ, and that Suminski's " En-
dosperm " is in fact the young plant. At the same time
I called attention to the facts that the antheridia and
archegonia of mosses exhibit in their structure the most
striking similarity to the like organs in ferns, and that
the development of the embryo of the vascular cryptogams
coincides in its principal features with that of the fruit in
mosses, inasmuch as in both those large groups of plants
the fruit is not developed in a continuous course of vegeta-
tion from the germination of the spore, but in both families
the development suffers a discontinuance ; in an organ
which has essentiallv the same structure in both families, a
cell originates, in which, after exposure to the access of
spermatozoa, an independent cellular body is formed, mor-
phologically distinct from the mother-plant, upon which
the mosses are dependent for the development of their
fruit only, but to which the ferns owe by far the most im-
portant part of their vegetative growth. In a work which
appeared shortly afterwards ('Lhma3a,' B. xxii, 1850, p.
753) Schacht also pointed out that the archegonia of ferns
are formed just like those of mosses ; that they are at first
closed, and are furnished at the base with a cavity sunk in
tlie tissue of the prothallium, which cavity is in communica-
tion with the canal which traverses the neck of the organ ;
that in the interior of the cavity, and probably inside a cell
clothing the cavity, the embryo is formed. Like myself,
Schacht considers that the filiform mucilaginous bodies in-
side the closed canal, which L. Suminski looked upon as
transformed spermatozoa, are the products of the transfer-

THE HIGHER CRYPTOGAMIA. 261

mation of the primary contents of the canal, and that
Smninski's endosperm is the embryo (1. c. p. 780). On
the other hand V. Mercklin's conclusion from the exami-
nation of the same object (' Beobachtungen am Prothallium
der Farrn-krauter,' Petersburg, 1850) was more in favour of
Snminski's views. V. Mercklin also thought that the young
archegonia were open, and believed that he had seen the
entrance of spermatozoa into such young archegonia, and he
assumed that it was not until a subsequent period that the
apex of the neck of the archegonium became closed
(1. c. p. 46). On the other hand he observed correctly the
bursting of the apex of the archegonium after its complete
formation (1. c. p. 33) as well as the presence of a globular
cell in the central cell (which like Schacht and Suminski he
took to be an intercellular space) before the bursting of the
latter (1. c. p. 31). To V. Mercklin also is due the merit of
the first reliable observations of the entrance of the motile
spermatozoa into the mouth of the neck of an opened
archegonium (1. c. p. 46 in Asplenium Serra). Mettenius
('Beitrage zur Botanik,' Frankfurt 1850, p. 18) arrived at
the same results as Schacht and myself. He first pointed
out that the development of an archegonium from a cell of
the prothallium, commences with the division of this cell
into two cells lying underneath one another (1. c. p. 19).

In my ' Vergleichende Untersuchungen ' Leipzig 1851,
p. 81, I added to the account which I had published two
years before. The principal points in the literature of the
sexual reproduction of ferns received a further confirmation
from a paper of Henfrey's in the ' Transactions of the
Linnean Society,' vol. xxi, p. 117, 1852. In 1851 I was
under the impression that the germinal vesicle of ferns
originated by renewed cell-formation round the primary
nucleus of the central cell, an error which I corrected in
1854 (' Sitzungsberichte K.Sachs. Gesellsch. d. Wissen-
schaft,' Math. Phys. CI. 1854, p. 54) when reviewing my
first observations on the motile spermatozoa in the centra]
cell of the archegonium. In a publication which appeared
soon afterwards, Wigand retracted his previous contradic-
tions of the statements of other observers, (Botanische
Untersuchungen, Braunschweig, 1854, p. 151) so that

262 HOFMEISTER, ON

botanists are now unanimous upon all the essential points
of the question.

The anatomy of the stems of ferns (the course of whose
vascular bundles had been supposed to be very similar to
that of the monocotyledons) was first clearly explained by
H. v. Mohl (de structure, caulic. filic. arbor, in v. Martins'
Icon, plant, cryptog. Brasil. Munchen 1835 ; translated in
H. v. Mold's ' Vermischte Schriften/ p. 108). He pointed
out that the closed vascular bundles (which do not increase
in thickness after they are first formed) in tree ferns as well
as in the herbaceous species form a hollow cylindrical net
concentric with the periphery of the stem, whose meshes, in
the species with crowded fronds (dsj)lfilix-mas for instance),
are arranged with the greatest regularity in the following
manner, that is to say ; from the place where each frond is
attached to the cylinder, two bundles pass to the bases of
the two next higher fronds, and two to the bases of the two
next lower ones. This regularity in the relation between the
anastomoses of the vascular bundles and the places of in-
sertion of the fronds, does not occur in the species with
distant fronds, such as Polj/podium aureum. The difference
between the tree-ferns and the herbaceous species is im-
material, depending upon the breadth of the vascular
bundle, and the development of the sheaths of the latter out
of woody prosenchyma. At the place where a vascular
bundle passes into a frond an entire bundle is never found to
bend itself outwards for that purpose, as is almost always
the case in phaenogams, but small ramifications only are sent
off into the fronds.* Later observations have not yielded
any additional results of importance.

Brogniart first made known that the ramification of the
stems of ferns is caused exclusively by bifurcation of the
extremity (' Histoire des vegetaux Fossiles,' ii, p. 30), an
opinion which has been supported by Stenzel (' Jahresb.
Schles. Ges.,' 1857, p. 85), and by myself. f On the other

* Unger's notion of the ferns and their allies as " Plantce acrobryce " is founded
upon this important peeularity (' Unger Bau und Wachsthum der Dikotyle-
donen-stamen/ Petersburg, 1840; ' Anat. und Physiol, d. Pfl.,' lS50,p. 225).

f My observations on this subject which are given in the preceding pages
were first published in the Transactions of the Royal Society of Sciences
of Saxony, vol v, p. 60. 1857.

THE HIGHER CRYPTOGAMIA. 263

hand, Karsten" (' Vegetation sorgane cler Palmen,' Berlin,
1847, p. 125), called attention to the definite relation which
so often occurs between the ramifications of fern-stems
and the insertion of their leaves ; and Mettenius lately en-
deavoured ('Abhandl. K. Sachs. Ges. d. Wiss./ vol. vii,)
to show that no essential difference exists between the
mode of ramification of ferns and of the vascular crypto-
gams generally, and that of phaenogamous plants, inas-
much as the ramification of ferns owes its origin to the
development of lateral buds, which are normally situated
in a definite position with regard to the bases of the leaves.
Mettenius draws his conclusions from a number of species
of Trichomanes, whose lateral buds he considered to be un-
doubtedly situated in the axils of the fronds. He finds
even in Hymenophyllum instances of the transition between
axillary buds and buds springing from the fore side of
the stipes. With these he classes the Davallieae, which
exhibit transitions from axillary buds to buds which ori-
ginate in front of and underneath the axil. Mettenius
finds the buds of Plati/cerium cdcicorne and of many other
species behind and underneath the insertion of the fronds,
and in Polypodium vulgare (amongst others,) he finds the
bud so far removed from the point of insertion of its
own proper frond, that it appears to be opposite the next
older one. Mettenius considers these lateral buds to be
of the same nature as those found on the stipes of Pteris
aquilina and Aspidium filkc-mas, which I look upon as
adventitious buds distinct from the true ramifications of
the stem. He adopts Karsten's view, that in Dicksonia,
in consequence of a bud of this nature being developed at
an early period before the development of the frond be-
longing to it, the frond which originally belonged to the
stem is withdrawn from the latter, and transferred to the
apparently dichotomous ramification of the principal stem.
Mettenius also agrees with Karsten as to the mode of
branching of the stem of Pteris aquilina.

If the object of this conception is to point out the
essential agreement between the ramification of the vas-
cular cryptogams and the axile position of the lateral
branches of pheenogams, it may be objected that the agree-

264 HOFMEISTER, ON

ment in question assumes a very different aspect, if the
view suggested by Pringsheim (' Bot. Zeit.,' 1853, p.
609), and supported by Irmisch ('Bot, Zeit./ 1858, p.
492) be adopted. According to tins view (which I con-
sider correct), all normal ramification rests upon bifurca-
tion of the end of the stem above the youngest leaf of the
bud, the result of which usually is, that one fork of the
branch developes itself more vigorously than the other, and
forms the prolongation of the principal axis, whilst the
other which is less strongly developed and is displaced side-
ways, forms a lateral branch. It is hardly necessary
to remark that the existence of a definite relation between
the positions of the branches and the leaves is entirely recon-
cileable with this view. No supporter of it has denied
the fact. In phgenogams the less-developed branch, —
which, in consequence of its inferiority of development
becomes a lateral branch of the more vigorously developed
one, — is usually inserted in the axil of the next lower
leaf, but this circumstance is of little importance, inasmuch
as no causal connexion is anywhere proved to exist, or as
far as we know even suspected, between the anatomical rela-
tions of the axil of the leaf and the insertion of the lateral
branch. Nothing is more certain than that the rudiment
of the lateral branch in all cases hitherto examined is formed
immediately after the commencement of the formation of
the phyllophore, and that the next higher leaf in a
vertical direction is first formed at a much later period. The
essential difference between the existing opinions relates
therefore only to the question whether the dichotomous
ramification of fern-stems and the formation of buds at the
base of the stipes of ferns are processes of a similar
nature; whether both stand in the same relation to the
principal axis as the axillary buds of phaenogams. Obser-
vation gives immediately a negative answer. The adventi-
tious buds which are situated upon the back of the stipes
of Aspidium filiae-mas, as well as those which are inserted
lower down in Pferis aquilina and Struthiopteris, are not
formed until the frond has reached a high degree of deve-
lopment, a fact quite at variance with the mode of produc-
tion of the axile buds of monocotyledonous or dicoty-

THE HIGHER CRYPTOGAMIA. 265

ledonous plants, and of the forked branches of ferns. I
should not adopt the definition given by Mettenius of
lateral and adventitious buds. I should call those buds
lateral buds, which originate from the naked apex of the
stem above the insertion of the youngest leaf, and are thus
formed by bifurcation of the end of the stem, whilst
owing to their inferiority of development they are pushed
aside by the other division of the forked end of the stem.
I should call those buds adventitious which make their
appearance underneath the insertion of the youngest appen-
dicular organ, whether on the outer surface or in the interior
of the tissue. The term Dichotomy might then be applied
to the cases of equal development of the two ends of
the fork of the stem. These definitions leave the doctrine
of ramification as established by Schimper untouched.
The fact, that in phaenogams that branch of the end of the
stems which is situated in the axil of the next lower leaf
is usually less vigorously developed than the other one,
justifies the assumption, that the cases in which the former
is more vigorously developed than the latter must be
looked upon as special instances of ramification. If a
comparison be made between the adventitious buds of
Aspidwm Jilix-mas (which are of frequent occurrence), and
the early conditions of the bifurcations of the apex of the
stem of the same species (which are of rare occurrence),
or between the bifurcations of the apex of the stem of
Asplenium filioc-femina (which are of frequent occurrence),
and the adventitious buds at the base of the stipes of
the latter plant (which are of very rare occurrence), it will be
self-evident than in these instances the two things are quite
as distinct as (for example) the bifurcations of the end of the
stem of Metzgeriafureata, and the adventitious shoots
which are developed from the marginal cells of the flat
stem of the latter plant.

Upon examining the bifurcations of Asplenium flliv-
femina whilst in a very early stage of development, after
having removed all the older fronds and scales, I found that
the two ends of the axis, when viewed from above, presented
the appearance of conical protuberances of equal size,
each surrounded by the rudiments of only three fronds.

266 HOFMEISTER, ON THE HIGHER CRYPTOGAMIA.

The arrangement of the fronds in both was antidromal,
and in one of them always passed by degrees into that of
the older undivided axis, whilst the frond-arrangement of
the adventitious shoots of Aspidium filix-mas is usually
homodromous with that of the principal stem, and rarely
antidromous to it.

With regard to Pteris aquilina the inadmissibility of the
views of Karsten and Mettenius is still more manifest. I
have seen stems of Pteris aquilina with naked fronclless
unbranched ends of considerable length, whose youngest
branch disclosed no rudiment of a frond. This was the
case (amongst many other instances) throughout a length
of eight inches in a portion of the end of a stem, and
throughout a length of 2^ inches in the youngest branch.
This is proof of undoubted bifurcation. The supposition of
Mettenius would also require that (when the first frond of
the sub-axis is inserted on the side turned towards the
principal axis) a bud inserted on the hinder edge of the
stipes should, by its early development, push away the
frond from the principal axis to which it belongs. It would
follow also that the front surface of its lamina must be
turned towards the latter, or in other words its stipes must
exhibit a tension of 180°. Neither of these two circum-
stances occurs.

Finally a real difference exists between the internal
structure of the forked branches of the stem and that of
the place of junction of the principal stem with the buds
which I have considered as adventitious and seated on the
stipes. The former exhibit throughout their entire length
the peculiar structure of the stem. Their two axile vas-
cular bundles, and the sheaths of the latter, are united
immediately with the corresponding portions of the tissue
of the principal axis. The tissue on the other hand which
lies between the principal axis and the place of origin of an
adventitious bud, exhibits the characteristic arrangement
of the vascular bundles of the stipes.

CHAPTER VIII.

EQUISETACE^E.

Equisetum arvense, pratense, variegatum, hyemale, pahsfre,

limosum.

The growing end of the stem of each shoot of the Equi-
setaceae consists of a blunt conical mass of cellular tissue,
and projects considerably beyond the place of origin of the
youngest leaf. The latter encloses the terminal bud in the
form of an annular cushion of uniform height. The next
youngest leaves are immediately underneath it, and closely
packed together. Their upper margins already exhibit the
first indications of the pointed lobes, into which the sheaths
which surround the base of each joint of the stem are pro-
longed (PL XXXV, figs. 6, 7).

The longitudinal growth of the stem* is produced by
repeated division of the large apical cell of the terminal bud,
which cell is three sided beneath, and sharply pyramidal.
The division takes place by means of septa which, following
a left-handed spiral direction, are successively parallel to
each one of the lateral surfaces (PI. XXXV, figs. 3, 4).
The cells of the second degree thus formed divide imme-
diately twice over, by means of vertical septa which make
acute angles with the lateral surfaces of the cell and pass
to its free outer surface in a gentle curve concave towards
these lateral surfaces. That septum is usually formed first
which is seated upon the older side-wall of the cell

* The cell -succession in the end of the stem of Equisetum was first correctly
described by Cramer (Nageli and Cramer, 'Pnanzen-physiol. Uutersuch./
Heft 4, Zurich). I had previously erroneously considered the form of the
apical cell to be that of a wedge. I have mentioned the cause of this erroneous
assumption in speaking of the cell-succession in the growing end of the stem in
Sphagnum,

268 HOFMEISTER, ON

(PL XXXV, fig. 3). The middle one of the three cells
which are produced in the interior of the cell of the second
degree (all of which lie in one plane) is the only one which
reaches to the middle point of the stem. It divides into
an inner and an outer cell by means of a longitudinal
septum almost parallel to the chord of the curved free outer
surface (PL XXXV, fig. 5). Both are divided by a trans-
verse septum, the outer one usually before the inner one
(PL XXXV, fig. 2). In the former this septum is parallel
to the upper and under surface of the cell ; in the latter it
is usually horizontal, and at right angles to the longitudinal
axis of the shoot (PL XXXV, fig. I). The stem forthwith
increases in thickness by repeated division of the cells of
the circumference by means of septa parallel to the free
outer wall. In very vigorous shoots, as for example in the
autumn shoots of Equisetum limosum, the like division occurs
several times in the cells of the next inner layer also
(PL XXXV, fig. 1). In such buds the cells of the circum-
ference usually divide once more by transverse septa close
above the place of origin of the youngest leaf. During the
increase of the stem in thickness the number of the cells of
its circumference increases continually by the division of
these cells by means of septa radial to the longitudinal axis
of the shoot or at least only slightly diverging from the
radial position. At first, in the upper part of the conical
cellular mass, this division alternates very regularly with
division by longitudinal septa parallel to the outer wall of
the cells ; lower down, where the stem becomes thicker,
division by a radial septum does not occur until after
several divisions by septa parallel to the axis of the stem.
The mass of the end of the stem which lies above the
youngest leaf, and the number of the cells of its longitu-
dinal axis and of its circumference are very different in
different species and even in the shoots of the same plant ;
they vary with the vigour of the shoots. By the early
occurrence of transverse division in the cells produced by
the multiplication of a cell of the second degree, the ladder-
like interweaving of the cells of the two longitudinal halves
of the stem is equalised at an early period. In those cases
in which this division does not extend into the cells adjoin-

THE HIGHER CRYPTOGAMIA. 269

ing the axis of the stem, it occurs at least once in the cells
of the circumference. On the upper surface of the stem
therefore an extremely regular circular girdle of cells is to
be distinguished. At a definite distance from the apex of
the terminal bud all its outer cells which lie at the same
altitude (a girdle of cells enclosing the end of the stem)
divide contemporaneously by a septum inclined to the
horizon (PI. XXXV, fig. 2). In the outer (the upper) of
the two cells thus formed, a division takes place by a sep-
tum inclined in an opposite direction. Thus an annular
wall of uniform height and embracing the terminal bud is
raised a little beneath the apex of the latter : this is the
first rudiment of the youngest leaf. All the cells of its free
upper edge continue to divide by alternately inclined septa
(PI. XXXV, fig. 1). The leaf at first grows upwards in
the form of a cylindrical sheath of uniform height enclosing
the terminal bud (PL XXXV, figs. 6, 7).

The place of origin of the youngest leaf, the girdle of its
mother-cells, is close above the place of attachment of the
next younger leaf. The leaf very soon after its production
begins to increase in thickness, the cells of its base, — those
of the under surface exclusively (PI. XXXV, fig. 1), —
dividing repeatedly by septa parallel to this surface. This
cell-multiplication progresses slowly from the base of the
leaf to its apex, and finally ceases at a considerable distance
beneath the latter. The outer (or lower) ones of the cells
thus formed, divide by transverse septa (septa parallel to
the ideal longitudinal axis of the leaf) the division being
more frequent in proportion as the shoot is destined for
more vigorous development. The great excess in the
number of the cells of the under surface of the leaf over
that of the upper, causes the free upper edge of the leaf
to bend inwards. By the vigorous multiplication of the
lower portion of the outer surface of the leaf, the base of
the leaf is soon transformed into numerous layers of cells,
parallel to the longitudinal axis of the shoot, and repre-
senting the outer circumference of the stem (PI. XXXVI,
lig. 1). The subsequent increase in length and thickness
of the joints of the stem depends upon the increase in

270 HOFMEISTER, ON

length and breadth of this cellular mass which has arisen
from the development of the basal portion of the leaf-rudi-
ment. The central cellular cylinder of the stem which has
arisen immediately from the terminal bud becomes exclu-
sively pith.* In the mean time by longitudinal division of
the cells of the leaf in a direction radial to the axis of the
stem — a division which occurs as well in the cells of the
under part which represents the outer layer of the stem, as
also in the free sheath-shaped upper portion — the number
of the cells of the circumference of the stem-joint and of the
hollow cylindrical leaf continually increases.

Shortly after the first appearance of the leaf there may
be observed an inequality in the activity of the growth of
its free upper edge. In the first place, at four points of
the leaf, one of the cells is about one step in advance of
all the rest in the process of division, which division takes
place by septa turned alternately towards and away from
the longitudinal axis of the stem (PI. XXXV, fig. 8). The
neighbouring cells on the right and left are about one step
in arrear : the cells adjoining the latter cells remain one
step further in arrear. Four short blunt points are thus
produced, placed in pairs opposite to one another upon the
upper edge of the sheath-like leaf. The multiplication of
the cells of the circumference of the free upper edge of the
leaf is produced exclusively by the division of the apical
cells of these points by means of longitudinal septa
(PL XXXV, fig. 8).f This division of the apical cells of
the tip of the leaf by septa radial to the circumference of
the leaf-sheath is often repeated at certain stages of the
growth of the leaf, and increases the breadth of the tip
more and more. Shortly afterwards the widened apex of
the tip of the leaf exhibits the first indication of a rapid
bifurcation (PI. XXXV, fig. 9). Thus with the age of the
leaf the number of the teeth of its edge increases; in

* From an opposite point of view, viz., the comparison of finished stages of
development, Spring arrives at the same conclusion for larger divisions of the
vegetable kingdom (' Monographic des Lycopodiacees, extraite des Memoires de
l'Academie Royale de Belgique,' Bruxelles, 1849).

f This mode of growth of the tip of the leaf brings strongly to mind that of
the shoots of Riccia, &c.

THE HIGHER CRYPTOGAMIA. 271

strong shoots of Equisetum limosum this increase takes place
with great regularity according to the progression 1 . . 4
7..8..9..10..11 and so on to 20 (PL XXXV, fig. 7).
At about the fourth or fifth leaf (reckoning backwards from
the uppermost youngest leaf) there occurs a very remark-
able longitudinal elongation of the cells of the apices of the
tip of the leaf. Even after its commencement, the multi-
plication of the cells of the base of the leaf in a longitudinal
direction by means of septa at right angles to the axis of
the stem continues for some length of time.

The relation of the outer cellular layers of the stem
(which are produced by the development of the outer side
of the base of the leaf-rudiment) to the central pith cylinder,
which corresponds with the cells of the free portion of
the terminal bud, is very different in the different forms of
shoots. In the few vigorous shoots which are usually
developed in autumn by the subterranean internodes of
Eqmaetum palustre and pratense,smd in a still more marked
manner in Equisetum limosum and Ityemale, the distinction
between the pith and the outer layer of the stem is visible
at a very early period : the cells of the latter even in the
youngest joints of the stem often divide repeatedly in a
longitudinal direction, whilst the multiplication of the pith
cells is quite at a stand-still. On the other hand this dis-
tinction occurs at a comparatively later period, and is not
nearly so well defined, in the delicate shoots which break
forth from the bases of the leaves high up on the stem,
especially in the thin shoots of the second, third, or fourth
order of Equisetum prateiise, arvense and limosum, or even
in the shoots of the first order of Equisetum variegatum.
The following table shows the number, in a longitudinal
direction, of the cells of the pith (a) and those of the
outer layers {b).

272

HOFMEISTER, ON

a

-

3
9

C!

03

i— i

s-

zz

a

i— i

d

i— i

>3

~ 1

i— i

a

b

4

5

4

4

4
3

4
4
8
4

4

7

32

8

4
5
8
6

6

7

4

7
8
4

4

7

40
9

b

a

4

a

4

b

8

a

*

«

4

In Equiselum palustre (a vigorous
shoot) . . . •

The same species, a very delicate
shoot .....

Eq. limosum (a shoot formed at
the end of May)

Eq. limosum (a vigorous autumn
shoot) .....

Eq. prafeu.se (a vigorous autumn
shoot) .....

Eq. variegutum (a delicate shoot)

The number of cells of the trans-
verse diameter in a vigorous
autumn shoot of Eq. limosum
amounted to .

In a delicate shoot of Eq. variega-
tum to .

4

4

4

4

4
3

22
5

7

9

10

7

6

7

4
9
8
4

4

7

48
12

8
12*
17

7

7
13

4

4

10

7

4

10

8

13f

58
12

...

...12

...

This comparison appears at the first glance to be quite at
variance with the common notion that the cells of the stem
are multiplied in a longitudinal direction only at the apex
of the organ. This opinion is untenable in any extended
sense. As far as observations go there are no plants, from
the mosses upwards, in which the cells of the stem are mul-
tiplied in a longitudinal direction exclusively by division
of the terminal cell. Generally the division of the daughter-
cells of the cells of the second degree by septa at right
angles to the longitudinal axis, plays an important part in
the production of longitudinal growth. On a more accu-
rate examination, however, the above table, shows that
there is a special tendency to multiplication in the cells of
those parts of the leaves which have been already some
time formed. It is only the cells of the cortical layers
(which my figure PI. XXXV, fig. 1, shows clearly to have
been produced by the multiplication of the cells of the leaf-
rudiment) which exhibit the long-continuous longitudinal

* Those of the epidermis 14. This fourth internode exhibited the first
indications of annular vessels, 5 — 6 rings in each of the cells of a longitudinal
row adjoining the pith.

f A trace of annular vessels was first visible in the 15th internode.

THE HIGHER CRYPTOGAM [A. 273

multiplication extending in many cases even beyond the
twelfth internode. In the cells of the pith only" a single
transverse division occurs . From the fact that the thick-
ness of the shoot is in such manifest connexion with the
period of the occurrence of the transverse division of the
pith-cells, it may perhaps be concluded that the immediate
operation of the outer air upon the tissue of the growing-
stem has an especial effect in promoting transverse division
in the cells.

The formation of the epidermis of the young stem-joint
is contemporaneous with its longitudinal extension, with its
appearance above ground, and with the formation of nu-
merous chlorophyll bodies in the cells of its circumference.
All the cells of the outer surface divide twice by transverse
septa, then by longitudinal septa, and lastly by septa paral-
lel to the outer surface. A double layer of cells is thus
produced, enclosing the circumference of the stem, the cells
being one-eighth the size and eight times as numerous as
those of the next inner layer. The outermost are trans-
formed into the epidermis ; every second cell of the epider-
mis of the above-ground shoots becomes the mother-cell of
two stomatal cells ; these as well as the tabular cells of the
epidermis exhibit upon the outer surface very regular pro-
jections the form of which is constant for each species (PI.
XXXVI, fig. 2). These projections contain more siliceous
matter than any other part of the stem.

The differentiation of the vascular bundles from the
surrounding tissue commences a short time before the for-
mation of the epidermis. The first commencement of the
vascular bundle consists in the appearance of annular fibres
in a vertical row of cells the position of which answers
exactly to one of the tips of the next higher leaf. From
five to six of these annular fibres occur in each cell (PI.
XXXV, fig. 13). A plane passing through the middle of
the tip of the leaf cuts the string of cells of the stem-joint
which bears the leaf, in each of which cells annular fibres
are formed.

The horizontal septa which separate the ring-bearing
cells from one another arc very soon absorbed, and a circle
of annular vessels traversing the entire length of the stem-

18

274 IIOFMEISTER, ON

joint is thus produced. At the time when the annular
vessel becomes continuous a multiplication commences in
the neighbouring cells — those situated in front (towards
the outside) and to the side — by means of vertical septa
alternating with radial septa and with septa parallel to
the periphery of the stein (PL XXXVI, fig. 1). Thus a
thick string of cambial cells is produced in which more
annular vessels (with much narrower rings) are shortly
afterwards formed in a similar manner, and where at a
much later period spiral vessels are also formed. In the
developed internode this string of cells represents a closed
vascular bundle.

The tips of each leaf and the corresponding vascular
bundles of each stem-joint alternate with those of the next
lower one. Soon after the first separation of the vascular
bundle from the surrounding tissue of the stem — which
separation takes place whilst the vascular bundle has still
the appearance of a string of cambial cells and exhibits
only a single annular vessel on its inner side — the cells of
the node from the base of the vascular bundle as far as
the two adjoining ones of the next lower stem-joint are trans-
formed into short spiral cells arranged in a moniliform
manner ; the cells which adjoin these strings in a lateral
and outward direction are transformed into a thin layer of
cambial cells which at a later period also take part in the
formation of vessels.

After the commencement of the formation of the vascular
bundle of the stem the corresponding leaf-tip exhibits the
transformation of a string of cells into a vascular bundle
traversing its median longitudinal line. The first vessels
which appear in the leaf are elongated, narrow, spiral
vessels. The vascular bundles of the leaf attain only a
slight thickness.

The distance from the middle point of the stem at which
the formation of vascular bundles commences — in other
words the bulk of the pith and the number of leaf- tips and
the (corresponding) number of the vascular bundles of the
internode which bears the leaf — is very variable according
to the activity of the growth of the shoot, and according to
the number of its diametral cells. In thin shoots of Eq.

THE HIGHER CRYPTOGAMIA. 275

variegatum m&pafastre the number of cells in the diameter
of the pith is only 6 ; in vigorous shoots of Eq. limosum it
is 40. The number of leaf-tips and vascular bundles
appears not less variable ; in the main shoots of Eq. varie-
gatum it is 7 j in Eq. palustre 7 — 10 ; in Eq.pratense 10 ;
in Eq. limosum 10—20. Most striking differences in this
respect are found even in the axes of different orders of one
and the same shoot.

The connexion between the cells of the pith of all the
indigenous (German) species of Equisetum is very soon
dissolved. The numerous intercellular spaces become filled
with air. The cells of the pith are soon unable to keep
pace with the longitudinal growth of the periphery of the
stem. All connexion between the pith-cells ceases, they
are torn from one another, they become shrivelled, and in a
short time disappear altogether with the exception of a flat
double layer of cells in each internode which lasts as long-
as the stem itself. Thus there is produced in each inter-
node a central pith-cavity covered above and filled with
air, having smooth side walls and a base rough with the
debris of the pith- cells. In just the same way — by the
separation of a string of cells from the adjoining tissue,
by the early cessation of the multiplication of these cells,
and by their shrivelling and desiccation — an air-cavity is
produced, in Equisetum limosum, around each vascular
bundle; and ultimately by the decay of the central por-
tion of the vascular bundle, a narrow air-cavity is formed
in the interior of each of them.

Normally, the terminal bud of the Equisetaceae never
ramifies. There is hardly any other group of plants which
exhibit such a well-defined, exclusively apical, growth.
Ramification is caused solely by adventitious buds.
These are produced in definite positions, viz., in the an-
nular locus of insertion of the sheathing leaf ; each adventi-
tious bud, with rare exceptions, being seated under the
angle between each two leaf-tips. The rudiment of the
adventitious bud appears long before .that of the vascular
bundles of the same internode. In the autumn shoots of
Eq. pratense which are developed in the following spring,
a cell, situated in the defined position at the base of the

276 HOFMEISTER, ON

leaf (often of the third or fourth-youngest leaf), and in
the second or third layer beneath the surface of the latter,
becomes distinguishable from the neighbouring cells (which
often already contain chlorophyll), by its increase in size,
and still more by its colourless thickly mucilaginous
contents. This cell often lags behind its neighbours in
longitudinal growth, in consequence of which its connexion
with the cells above it and at its sides is dissolved. Division
soon commences in it, and is repeated in different directions
in rapid succession in the terminal cell. (PL XXXV, figs. 1 1 ,
12). Thus a cell-multiplication is set on foot which corre-
sponds in all respects with the preceding multiplication of
the apical cell of the terminal bud. The presence of the
adventitious bud is soon indicated by a protrusion of the
outer surface of the stem close under the place of insertion
of the leaf. Ultimately by further longitudinal growth
it breaks forth from the under-side of the sheath-like
leaf.

The adventitious buds of Equisetum have the peculiarity
of being able, under certain circumstances, to remain long
dormant, a peculiarity which they possess in common with
the adventitious buds which arc produced in mosses and
phrenoganis upon the outer surface of the young stem
in the axils of leaves. They often pass the greater portion
of a period of vegetation in the most rudimentary condi-
tion, consisting of one or at most of a few cells. This is
the case with the adventitious buds of E. pratense, palustre,
and limosum, which are destined to reproduce the species.
Although in spring numerous thin branches break out from
the base of the leaf-sheath of the middle and upper part
of the above-gronnd shoots, the number of which branches
is usually the same as that of the leaf-tips, yet the adven-
titious buds of the lowest internodes — those which are
buried in the earth — remain entirely dormant until late
in autumn. At that time, however, one only of the buds
of each of those internodes developes itself but with a
strength and activity which far exceeds that of the subter-
ranean branchlets.

Individual internodes of the lower subterranean portion
of the main shoots of Eq. arvense become swollen, whilst

THE HIGHER CRYPTOGAMIA. 277

the cells of the tissue which surrounds* the circle of vas-
cular bundles multiply vigorously. Vigorous adventitious
buds are formed at the base of the rudimentary leaf of such
internodes ; seldom more than two in the same internode.
The cellular tissue of the swollen internodes contains starch
and a good deal of sugar, I believe not crystallized.
The different habit of the species of Equisetum depends upon
the relation of the adventitious lateral shoots to the principal
shoot. In all the above-named species (arven.se, pratense,
variegatum , liyemcde, pain -sire, limosum), the lowest leaves
of those shoots which have completed their subterranean
development, send out vigorous shoots destined for develop-
ment in the following season, a process which brings to
mind the buds which occur in the cataphyllary region of
many phamogams. These shoots are the least developed
in Eq. arvense ; they are of an elongated cylindrical form,
and very beautiful and vigorous in Eq. jpratense and limosum.
In the latter species they protrude, even in autumn, for
a distance of several inches from the base of the sheathing
leaves ; in JEquisetum palustre they appear at the beginning
of spring; in Eq. hyemale at the end of April. Those
of Eq. limosum deserve a closer investigation, not only
on account of many peculiarities dependent upon habitat,
but also on account of the injury produced by its abundant
growth in the richest water-meadows of North Ger-
many, where the hay is frequently uneatable from the ad-
mixture of numerous shoots of the Equisetum. As in the
other species of the genus, the lower part of each shoot
(unlike the portion above ground), does not die until the
autumn. The epidermis of this portion of the stem assumes
a beautiful reel-brown colour; from one to three shoots,
destined for development above ground in the following-
year, burst forth in an upward direction out of the hollow
cylindrical leaves, whose upper portion dies and withers.
The epidermis of these winter shoots is of the colour of
ivory, and the tips of their leaves of a chestnut-brown. If
the shoots are exposed to the light, chlorophyll is developed,
even in autumn, in the cells of the circumference. Be-

* Compcire Bischoff ' Krvptogamische Gewachse,' Nurnb., 182S, Heft i,
p. 29.

278 HOFMEISTER, ON

sides these shoots others are developed here and there
on individual joints of old stems : the latter have a lateral,
not an upward direction ; their colour in the young state
is a deep citron-yellow, and their leaf-sheaths are of a deep
black-brown. Unlike those first described, they are not
blunt at the top, but the connivent tips of the sheathing
leaves of the terminal bud form a sharp apex. These
shoots are the foundation of the creeping rhizome, and some-
times attain a length of twenty feet. When they emerge
from the leaf-sheaths of the mother-shoot they are of the
thickness of a slender goose-quill, but afterwards by expan-
sion of their cells, and by gradual increase in the number
of the cells of the new internodes in a diametral direction,
they attain from half to three-fourths of an inch in thick-
ness. From the bases of their leaf-sheaths a few shoots are
produced separated from one another by considerable in-
tervals (by several internodes, which produce no adventitious
buds), and which are destined partly for development above
ground, and partly for the formation of new Rhizomes.

In those species of Equisetum which are found in damp
localities away from the light, a girdle of adventitious roots
is formed at each node of the stem, on a level with the
septum which traverses the pith cavity, and close under-
neath the rudiments of the adventitious buds. They
originate close underneath the bark, immediately below the
lower ends of the vascular bundles of the next superior
internode, and consequently meet the upper ends of the
septa which separate the cortical air-cavities of the next
lower internode. In the lower nodes of the vigorous
autumn shoots one at least, usually two, and often three
such adventitious roots are formed close to one another.
At an early period the cells of that portion of the partition
wall of two cortical air-cavities which leads from the
adventitious roots to the convergent prolongations of
the vascular bundle are transformed into a single vascular
bundle traversed by numerous short spiral vessels. The
origin of these thick vascular bundles, which are attached
to the spreading prolongations of the vascular bundles
of the internode, renders the course of the vascular bundle
of the stem within the node quite indistinct ; they

THE HIGHER CRYPTOGAMIA. 279

may have given rise to the opinion that the vascular bundles
of the stem of the Equisetacese unite in each node to form
a confused mass of tissue.*

The normal mode of cell-multiplication in the pimctum
vegetationis of the adventitious roots is identical with that
in Aspidiumfilias-mas. The cell of the first degree, whose
continuous division is the cause in the first instance of the
growth of the root lies in the interior of the tissue, nearly
above the apex of the root. Its form is tetrahedral. It
divides by septa of which three in succession are each of
them parallel to one of the three lateral surfaces, and of
which the fourth forms the surface of a segment of a sphere
seated upon the basal surface which is turned towards the
apex of the root. In this way sets of four cells of the
second degree are formed, of which the three upper, which
adjoin the cell of the first degree, take part in the forma-
tion of the permanent portion of the root ; the fourth, by
its multiplication produces one of the hood-shaped hryers of
the root-tap. Soon after its formation four cells, having
a quadrantal basal outline, are produced in its interior
by a twice repeated division by means of vertical septa.
The cells produced by the multiplication of one of the lower
cells of the second degree henceforth divide only by septa
perpendicular to the basal surface of the mother-cell and
consequently to the next adjoining portion of the surface of
the root. All the daughter-cells of such a cell of the second
degree lie in one place which is curved parabolically ; they
form a blunt hollow cone, and the number of these cones
which envelope the apex of the root is the same as that of
the cells of the second degree directed downwards which have
originated in their puncta vegetationis. The oldest, outer-
most of them, reaches as far as the place of origin of the
root, the younger, inner ones, are gradually less in proportion
to their age. The oldest outermost cellular layers of the
apex of the root scale off by degrees and become decayed.

The cell-multiplication of those cells of the second degree
which are directed upwards tends much more to the increase
of the number of cells in height than in breadth. The lon-
gitudinal division of each such, newly formed cell is
* See Nageli, ' Zeitscbrift f. Botanik./ Heft 3 and 4, p. 143.

280 HOFMEISTER, ON

followed by division by means of septa parallel to the basal
surface, and perpendicular to the longitudinal axis of the
root, The outer cells of the group formed by the multi-
plication of those cells of the second degree which are
directed upwards (those which adjoin the daughter-cells of
the second degree which are directed downwards) continue
to multiply for some time by division by means of septa
alternately radial and parallel to the periphery. But the
succession of these divisions is twice interrupted by the
formation of horizontal septa in the entire mass of cells pro-
duced by the multiplication of the cell of the second degree
which is directed upwards.

The adventitious roots like the adventitious buds are
capable of remaining dormant for a long time. When they
burst forth and become elongated, the central string of cells
is transformed into avascular bundle. The tissue immedi-
ately enclosing the latter becomes disintegrated, dries up,
and ultimately disappears. Thus a hollow cylindrical air
cavity is produced beneath the bark of the adventitious
root, The upper surface of the root becomes covered with
long papilla? which become brown in age. In very old
rhizomes the cortical layer of the root usually disappears
entirely; the central vascular bundles only, (whose tissue
is very firm) are persistent, and have the appearance of
tough, thick, deep-brown fibres.

Fruit is usually developed only on the vigorous shoots
produced from the lowest internodes of a shoot of the
previous year. The transition from the form of the ordinary
sheathing leaves, to that of the lowest circle of sporangia is
very rapid and sudden, even in those species which (like
Equisetum arvense) have special fructifying shoots. The
sheathing leaf immediately underneath the fruit is shorter
and more fleshy than the others ; there is no other inter-
mediate condition. The fructification is morphologically
unlimited ; owing to its mode of origin its longitudinal
development is not confined within bounds, any more than
that of the vegetative shoots, which (at least those above
ground) nevertheless do not become elongated beyond a
certain extent. Each circle of sporangia makes its appear-
ance in the form of an annular cushion underneath the

THE HIGHER CRYPTOGAMIA. 281

terminal bud,* like the first rudiment of the vegetative
leaf, but more massive and much less elevated.

Definite points in this very flat annular wall become
prominent, after the maimer in which the leaf tips
project above the (originally) smooth margin of the
sheathing leaf. A ring of hemispherical protuberances is
thus produced around the stem, which, in the growing
fruit, is clearly perceptible in the third rudimentary
sporangial circle, reckoning from the terminal bud down-
wards (PL XXXVI, figs. 3, 6). The normal cell-multipli-
cation of these hemispherical cellular masses — the rudiments
of the stalks of the sporangia — is similar to that of the
fruit-rudiment of Pellia (PI. XXXVI, figs. 4, 5). The
development of their upper part soon exceeds that of the
lower ; by the pressure of their apices against one another
they assume the form of hexagonal shields. On the under-
side, where they pass into the stalk, these shields soon
exhibit at five or six points a rapid cell-multiplication pro-
duced by the division of one of the cells of the under surface
of the shield. This division takes place by septa inclined
in different directions, and is repeated continually in the
apical cell (PL XXXVI, fig. 7). Prom five to six blunt
warts of cellular tissue are thus produced on the under side
of the shield : these are the first rudiments of the sporangia.
Shortly after their first appearance the growth of one of the
inner cells considerably surpasses that of its neighbours.
The cell in question is at this time only separated from the
apex of the young sporangium by a simple layer consisting
of a few cells. It is the primary mother-cell of the spores ;
the cells surrounding it become the wall of the sporan-
gium.

The first division of the primary mother-cell takes place
by a horizontal septum (PL XXXVI, fig. 8). By repeated
bi-partition of the primary mother-cell the number of cells
destined for spore-formation is increased (PL XXXVI,
figs. 9, 10). In the mean time the number of the cells of
the wall increases much more rapidly : the latter soon con-
sists of a double layer produced by the division of its

* The structure and mode of cell-multiplication of the terminal bud exactly
correspond with that of the terminal bud of vegetative shoots.

282 HOFMEISTER, ON

cells by septa parallel to the outer surface (PL XXXVI,
fig. 9). A previous division takes place by septa which
cross one another in different directions, and are perpen-
dicular to the outer surface, and by such division the cir-
cumference of the wall is increased, keeping pace with the
increase in volume of the group of mother-cells. In the
mean time the division by septa parallel to the outer surface
occurs once more, so that now the wall of the sporagium
consists of three layers of cells (PI. XXXVI, fig. 10).

The inner one of these layers and the middle one be-
come dissolved, and are displaced by the group of mother-
cells, the size of which increases continually. The inner layer
is dissolved at an early period, and the middle one shortly
before the time when the mother-cells are individualised
(PI. XXXVI, fig. 13). The connexion between the mother-
cells is not broken up all at once. Small groups, consisting
normally of four cells, usually hang together for some time
(PL XXXVI, figs. 11, 12). This process corresponds ex-
actly with what takes place in the formation of the pollen
of phaenogams.

Each of the spore-mother-cells when free exhibits a large
central nucleus, as is the case at all periods of their deve-
lopment, except immediately before the division of a gene-
ration of mother-cells. This nucleus, which usually has
only one moderate-sized spherical nucleolus, is a globular
empty cavity, having a vesicular appearance, and is filled
with fluid which is less highly refractive than the thickly
mucilaginous contents of the cell, which are rendered turbid
by numerous fine yellowish granules. In the further
progress of the development of the fruit the membrane
of this nucleus is slowly dissolved : its fluid contents do
not intermingle with that of the cell (PL XXXVI, fig. 12;
PL XXXVII, fig. 1). In its place two large flatly ellip-
soidal nuclei suddenly appear occupying almost half the
mother-cell. These latter nuclei at first exhibit no nu-
cleoli, but at a later period they contain several (PL
XXXVI, fig. 3). In the equator of the cell, between
the two nucleoli, a ring or plate of protoplasmic granules
is formed near the cell-wall (PL XXXVII, figs. 4, 5).
The outlines of the two flattened nuclei then become more

THE HIGHER CRYFTOGAMIA. 283

and more indistinct, and soon disappear altogether. The
granules which compose the above-mentioned ring or plate,
distribute themselves in the fluid contents of the mother-
cell, and four smaller globular nuclei are now seen in the
latter, whose appearance is as sudden as that of the two
larger flattened nuclei, which took place a short time pre-
viously (PL XXXVII, fig. 6). They are arranged in the
angles of a tetrahedron, and a septum is visible between
each two of them. Introductory stages of the development
of the septum may be seen in the form of thick indistinct
flattened agglomerations of yellowish protoplasm. Thus
the mother- cell is divided into four tetrahedral cells which
are the special-mother- cells (PI. XXXVII, figs. 7, S).

Hitherto the development of the spores, from the separa-
tion of the mother-cell down to the minutest details, re-
sembles that of the pollen of the Abietinege.* This renders
their further history so much the more peculiar.

The four tetrahedral cells into which the mother-cell
divides, very soon become disunited, doubtless on account
of the dissolution of the primary w^all of the mother-cell,
and of the outer layer of the walls of the four daughter-
cells. They then appear in the form of perfectly spherical
very thin-walled cells. A layer of granular mucilage covers
the inner wall, leaving in the centre a free globular cavity
filled with a thin fluid. The, very flat nucleus is embedded
in the protoplasmic layer. The globular cell, when lying-
in water, soon appears surrounded by a bright halo, formed
of a layer of apparently gelatinous matter, which when
treated with iodine exhibits no colour. (PI. XXXVII,
fig. 9). A very delicate membrane forms the outer boun-
dary of this covering layer. In somewhat older sporangia
this membrane appears more firm, and more distinctly
separated from the inner part of the layer surrounding the
globular cell, which now consists of a fluid coloured pale
yellow by iodine. These stages of development of the
spore-mother-cell are passed through in a very short time.
In the same sporagiura of Eq.palustre there may be found
mother-cells with the primary nucleus in the act of disso-
lution, others with two flattened nuclei, and others with

* 'Bot. Zeit.,'18-48, p. 670.

284 H0FME1STER, ON

four globular daughter-nuclei; there may also be found
sets of four tetrahedral daughter- cells, individual daughter-
cells, of a globular form, and lastly, others which already
exhibit the transparent halo slightly developed. The ap-
pearance of the latter is not accompanied by any percepti-
ble contraction of the contents of the globular cell. If the
cells which, when treated with water, exhibit the above-
mentioned halo, are examined in the fluid contents of the
sporangium, their membrane appears thin and quite homo-
geneous even under the best microscopes. But in sporangia
a little more advanced, the membrane in question under
similar circumstances appears to be composed of two layers,
the inner one of which is thicker and more highly re-
fractive than the outer one. The outer layer, when treated
with alcohol, contracts so as to be hardly distinguishable
from the inner one. At the same time the cell-contents con-
tract, sometimes into a globular shape, sometimes irre-
gularly. If water is applied the outer layer swells con-
siderably, and forms a thick, gelatinous, almost fluid cover-
ing, round the inner one, which remains unaltered. Under
the further action of water this gelatinous layer is dissipated
in the surrounding fluids. The effect of alcohol upon the
fresh cell is to lessen considerably this power of distension.
After treatment with alcohol the outer layer only swells up
to a definite extent (to about three times its original size),
in distilled water. If the preparation is now crushed, the
swollen layer is pressed out over a wide space, and is then
clearly seen to consist entirely of a homogeneous hyaline
gelatinous substance, and that the granular aspect of its
outer surface is owing to the attachment of small extrane-
ous bodies. A longer exposure to the effect of alcohol
often entirely destroys the capacity for distension.

Iodized solution of chloride of zinc imparts a pale blue
colour to the entire mass of the outer membrane, and
renders the inner one yellow. After the cells have lain in
alcohol the same solution renders the outer layer pale yellow,
and the inner one brown. The addition of water brings
out the blue colouring in the outer layer. Ammoniated
oxide of copper applied to the fresh cell causes only a slight
distension of the outer layer, and hardens it so that it no

THE HIGHER CRYPTOGAMIA. 285

longer spreads out under pressure. Sulphuric acid dissolves
the outer layer ■ the inner one withstands its action but
assumes a brown colour. At this period of development
the diameter of the cell is from 20*24 to 23 60 m. m. m.
and no trace of any third inner membrane is perceptible,
even when the cell is ruptured after lying in alcohol.

But when the cell has attained a diameter of from 303
to 37 m. m. m. a third internal covering of the cell-content s
soon makes its appearance. Such a cell when placed in
diluted alcohol exhibits three perfectly distinct membranes.
Each of the three globular vesicles is situated excentricallv
in the interior of the next outer one. If the fresh cell is
placed in alcohol the three membranes swell up but in dif-
ferent degrees : the outer one swells the most, the middle
one to a less extent than the outer, and the inner one least
of all. The cell-contents swell up at the same time ; they
always remain closely attached to the inner membrane, and
cannot be brought to contract into a smaller space than
the cavity of the latter. In a cell for instance whose diameter
in alcohol was 30*2 m. m. m. the membrane immediately
enclosing the cell contents measured (after treatment with
water) 32 m. m. m.; the middle one 37'04 m. m. m.; and
the outer one 63*84 m. m. m.

At this stage of development the iodized solution of
chloride of zinc colours all three membranes blue ; t he-
middle one changes colour first, and its colour is the most
intense. If such cells, after lying in alcohol, are ruptured
by pressure, the membranes, which have previously been
closely attached to one another, separate ; the middle one
contracts to a smaller space than the outer one, and the
inner one more than the middle one. After contrac
tion they still retain the form of tense globular vesicles,
and exhibit a Greater thickness of wall than before. If
cells fresh from the sporangium are treated with water, the
outer and middle membranes often swell up to some extent :
they separate from the inner layer, remaining at the same
in close connexion with one another. The distended mem-
branes are easily separable from one another by pressure,
and they exhibit a scarcely perceptible increase in thickness.
At this period no trace is yet visible of the course of the

286 HOFMEISTER, ON

spiral bands into which the outer membrane shortly after-
wards divides.*

In those sporangia however in which some cells of the
outer membrane exhibit traces of elater-formation and others
do not, the capacity for distension of the middle membrane
is far behind that of the outer one. Even in the fluid con-
tents of the sporangium itself the outer membrane, in
Uquisetum limosum, is at a considerable distance from the
middle one. Upon treatment with alcohol the middle and
the inner membrane are drawn far away from the outer one
whilst they remain in close contact with one another, and
with the cell- contents. Upon the subsequent addition of water
the inner membrane remains still in close contact at every
point with the cell contents ; the middle one becomes some-
what detached and often irregularly folded ; and the outer
layer is far removed from the middle one. With this dis-
tension of the outer membrane it becomes manifest that
the latter is traversed by two left handed, parallel, spiral
lines, in the course of which the membrane is thinner than
in its other parts. In profile, *. e., in an optical longitu-
dinal section of the cell, I see with the best microscopes
that the thicker portions of the membrane protrude inwards
over the thinner parts (PL XXXVII I, fig. 10), not out-
ivard///f as Sanio says (' Bot. Zeit./ 1857, p. 661). When

* In the ' Vergleichende Untersuchungen,' p. 99, I spoke of the processes
above described as consisting of the formation of a free cell (the spore) around
the primary nucleus of the special mother-cell. In opposition to this, Sanio
has shown ('Bot. Zeit./ 1856, p. 181, 1857, p. 057) that within the sporangium
the two membranes always lie close to one another, and that therefore a free
cell- formation cannot be admitted. This is quite correct. Sanio further
attempted to show that there could be no such thing as a centripetal spiral
thickening of the outer cell-membrane, which membrane at a later period splits
to form the elaters. The reasons brought forward to prove this are however
not convincing. During the development of the spores of the Equisetacea:
some phenomena occur which have an important-bearing upon the study of the
cell-membrane, and I therefore give here in some detail the result of recent
investigations of this subject. Some of Sanio's objections to my views as to
the divisions of the mother-cell (1. c, 1856, p. 170) have since been abandoned
by himself (1. c, 1857, p. 658). With regard to his observations on the
abnormal development of certain mother-cells and the division of the primary
nucleus by constriction, I will only remark that there is no analogy between
such cases and the cases where the process of development is normal.

-j- I contend that my representation (' Vergl. Unters.,1 t. xx, f. 18) is quite
correct, irrespective of the fact that in this figure the thin portions of the
membrane have come out disproportionately thick,

THE HIGHER CRYPTOGAMIA. 287

in water the outer membrane, which is in the process of
being transformed into elaters, is coloured pale blue by
iodized solution of chloride of zinc ; in the middle layer the
blue is more intense.

In sporangia a little more advanced the thin parts of the
outer membrane disappear : the delicate pellicle which held
together the coils of the elaters is no longer present. Fresh
elaters are coloured a QTeyish-blue by the above-mentioned
solution, with the exception of a thin outer layer which
assumes a yellowish colour. By adding a quantity of
water the colour of the main portion of the elaters becomes
a more pure blue. After the separation of the elaters the
middle spore membrane exhibits a very different reaction
with iodine ; it remains yellow under all circumstances,
under the iodized solution of chloride of zinc, as well as
under iodine and sulphuric acid. Animoniated oxide of
copper if applied to the outer membrane just after it has
split to form the elaters, is very rapid in its effects. The
membrane becomes distended and is gradually dissolved.
Under the action of the same fluid the next inner membrane
swells up into a large vesicle, without diminishing per-
ceptibly in thickness. Its substance is then softer; by
rolling it under a covering glass it is easily Avrinkled. The
third membrane is tightly stretched upon the cell-contents.
The further action of ammoniated oxide of copper gives it
a yellowish colour, but in other respects it remains un-
changed.

A little later, whilst the elaters are continually increasing
in breadth and thickness, the rudiment of a final innermost
membrane of the spore becomes visible. If a young spore
in this stage of development is detached from its elaters,
and placed in alcohol, and if water be then added, the
membrane next to the elaters becomes detached from the
third membrane, and from the cell-contents which are
closely embraced by the latter, and in which chlorophyll
now begins to appear. If the spore be now ruptured by
pressure, the membrane next to the elaters remains folded
without changing its volume. The next inner one remains
after the rupture tense as before, whilst it contracts upon
a much smaller space, and now appears considerably thicker

288 HOFMEISTER, ON

than it previously was. It has borne a strong pressure
from the expanding cell-contents, and possesses a high
degree of elasticity. Its hitherto smooth outer surface
now exhibits Aery small protuberances which give it a
finely granular appearance. Its inner surface is covered
by a tolerably thick layer of semi-fluid hyaline matter,
which by hard pressure is partly driven out from the
fissure of the ruptured membrane. If a spore in the
above stage of development be taken fresh from the sporan-
gium and treated with caustic potash, the elaters swell
up ; the adjoining membrane is distended into a vesicle,
and usually becomes wrinkled. The third granular mem-
brane assumes a brown colour, but in other respects re-
mains unchanged. The fourth membrane, which is still
delicate, contracts round the cell-contents, and exhibits a
double outline.* The peripheral portion of the cell-con-
tents then assumes a red colour, which never extends so
far as the middle point of the cell, and which depends
upon the presence of tannin. f Sometimes in spores taken
from the same sporangium, like those just mentioned, the
innermost layer swells up under caustic potash, and remains
in contact with the granular layer. The latter may then
be stripped off from the inner layer by friction with the
covering «;lass, and will be seen to be a closed vesicle sur-
rounding the cell-contents. Sulphuric acid immediately
destroys the elaters of such spores ; the next inner mem-
brane, like the third granular layer, thereupon expands
into a capacious vesicle, but resists the acid. The fourth
innermost layer swells, and becomes converted into gela-
tine, which after the rupture of the cell is immediately dis-
persed in the surrounding fluid.

After the bursting of the ripe sporangia; the elaters, when
dry, arc stretched out, remaining attached to the spore by
their median portion. When moistened they roll together

* Sanio, 1. c, p. 665, who from its contractility, draws the conclusion that it
is a primordial utricle.

f Sachs, ' Sitzungsb. Wiener. Acad.,' xxxvi, (1859) p. 21. Sanio has observed
that the red colour only ail'ects the cell-contents, 1. c, p. 666.

J The wall of the sporangia, which consists of one layer of cells, is trans-
formed into spiral cells. Compare Henderson, 'Trans. Linn. Soc.,' v, xviii,
p. 567.

THE HIGHER CHYPTOGAMIA. 289

in a spiral manner, covering the spore entirely as at first.
It may easily be seen by the examination of detached
fragments of elaters that the rolling inwards is not accom-
panied by any contraction of the concave side. It follows
from this that the extension of the elaters depends upon a
relatively greater contraction of the outer layers of their
tissue, a contraction which is completely 'balanced by
moistening the elaters. By moistening the ripe dry spores
the elaters are rapidly rolled inwards ; almost immediately
afterwards they become unrolled. Sulphuric acid and water
also causes a rolling inwards of the elaters : when concen-
trated to a certain extent it destroys only the inner layers.
The thin outermost layer, which during the formation of
the inner layer Avas coloured yellow by iodized chloride of
zinc (Pringsheim's * Elater-cuticle/ Bot. Zeit., 1853, p.
244), remains behind in the form of a loose band. The
second (now the outermost) membrane of the spore, be-
comes distended and detached from the middle layer by
the action of sulphuric acid, whether concentrated 'or
diluted. The inner spore-membrane is largely distended
by concentrated sulphuric acid, so that it soon ruptures
both the outer membranes, and emerges with the spore-
contents in the form of a gelatinous globule (PL XXXVIII,
lig. 11). The two outer membranes are not affected by
heated sulphuric acid, not even by remaining in the acid
for ten days. The outer layer under such circumstances
remains at first as clear as glass, and afterwards only ex-
hibits a smoky-grey colour and a granular consistency of
the outer surface. The inner layer which is finely granular
is coloured deep brown. After the rupture of the spore
all its membranes contract considerably, so that the diameter
of their inner cavity is only about half the previous size. If
the rupture of the spore is effected by treatment with sul-
phuric acid the contraction of the middle (third) mem-
brane, and consequently the elasticity upon which this
contraction rests, appears to be altogether unaffected, and
that of the outer membrane is but slightly acted on. After
the bursting, by pressure, of the fresh, ripe, detached spore,
the outer boundary only of the innermost (fourth) mem-
brane is sharply defined ; the inner side of the latter mem-

19

290 HOFMEISTER, ON

brane becomes by degrees a half solid gelatinous layer.
It is not until germination that this membrane becomes
smooth and firm on both sides. The expansion of the
cell-contents and of the innermost membrane which takes
place when the spore is sown upon moist ground, very
soon ruptures the outermost of the three membranes, and
shortly afterwards the middle one also, and both are stripped
off. The substance which is coloured red by caustic
potash remains attached to the inner wall of the innermost
membrane after the latter has become free, and even for
some time after its division into two cells. This substance
has the form of a layer composed of very minute particles,
and it may be detached by pressure from the cell-mem-
brane.

Two facts in the process of development of the spores of
the Equisetaceas are of general interest. The spore-mem-
brane is here seen to increase in thickness after two differ-
ent modes of growth occurring side by side. There is
growth by apposition and growth by intussusception. To
the former is to be attributed the origin of the third and
fourth membranes, which are evidently produced from the
gradual hardening of layers of gelatinous matter spread
over the inner surface of the previously existing membranes.
To the latter belongs the centripetal growth of the elaters,
after their separation from one another, and the centrifugal
growth of the second and third membrane during and after
the formation of the fourth ; a growth which exhibits itself
in the granulation of the outer surfaces of both these mem-
branes. The second point, however, is the more important one,
viz., the remarkable modifications of the physical properties
and chemical reactions which each of the four membranes
of the spore undergoes during the process of development.
Each of them exhibits during a certain period of its exist-
ence the assumed characteristic relation between cellulose
and iodine and sulphuric acid ; but this relation is never
seen in the earliest states of development, nor is it constant.
The outer layer of the first membrane (i, e., the elaters),
and of the fourth membrane (even after the commencement
of germination), assume in the course of development the
character of a cuticle ; the second and third maintain that

THE HIGHER CRYPTOGAMIA. 291

character throughout. The three outer membranes when
young are far more capable of distension than at a later
period, and during this condition the second and third
membranes are not without a high degree of elasticity,
which diminishes as the capacity of distension becomes less,
or even disappears altogether.

Sanio* has made some interesting observations upon the
abnormal formation of elaters out of the membranes of
mother-cells in which the division into four daughter-
cells has been suppressed. Since these observations it can
hardly be doubted that the outermost membrane, which is
transformed into elaters, must be looked upon as their
special-mother-cell. The Equisetacese, therefore, exhibit
the rare circumstance of the persistence of the membrane
of the special-mother-cell, a fact which, as far as I know,
occurs in phsenogains only in Maranta Zebrina. During the
transformation of the membrane of the special-mother-cell
into elaters a change in the substance of the membrane
appears to take place. Spiral strips of the membrane be-
come thinner and ultimately disappear, whilst other strips
parallel to these increase in thickness. The differentiation
of the membrane in a superficial direction into strips of
different characters, may be compared with its differentiation
in the direction of the thickness into two lavers of different
properties.

In the ripe spores the central globular nucleus is very
clearly visible floating in the yellowish oleaginous fluid
contents, in which, even before the shedding of the spores,
numerous chlorophyll granules are seen. The number of
the latter increases rapidly when the spores are sown on
moist ground. After a few hours the primary nucleus
vanishes. In its place two new ones make their appearance,
the position of which can often only be made out by means
of the agglomeration of chlorophyll-granules in their
neighbourhood (PL XXXVIII, fig. 12). Between the two
a septum is formed, dividing the spore into two very un-
equal parts (PI. XXXVII, fig. 13). One of these, the
larger one, contains almost all the chlorophyll-granules of
the cell : the other has hardly anything but finely-granular

* fBot. Zeit.,'1857, p. 667.

292 HOFMEISTER, ON

mucilage. This latter cell usually constitutes the first
radicular hair of the growing prothallium (PL XXXVI I,
figs. 14—16).

In Equisetum limosum and palustre the upper chlorophyll-
bearing cell divides immediately by a vertical or strongly
inclined septum (PI. XXXVIII, figs. 15, 10). In Equi-
setum arvense the cell often expands to a very considerable
extent before it divides, especially when the spore is sown
in a very moist shady place (PI. XXXVIII, fig. 19). The
formative matter — protoplasm mixed with numerous chlo-
rophyll-granules— is accumulated at the apex of the upper
cell, which is turned away from the rooting end of the
growing prothallium. This mucilaginous mass usually, but
not always, surrounds the nucleus. The latter dissolves
gradually and two new ones take its place (PI. XXXVIII,
fig. 19). A transverse septum, which makes its appearance
betwreen the two, divides the large chlorophyll- bearing cell
into an upper, smaller cell, destined for further active division,
and a lower, distended, permanent cell (PI. XXXVII, fig. 20).
The basal cell often grows into a tubular root after the
previous growth of one or more capillary roots from the
free outer wall of the younger cells. Frequently, however,
this does not take place (PI. XXXVII, fig. 20).

The further development of the prothallium is very
various. There is hardly any organ of the higher plants
in which there is so little regularity of cell-multiplication.
Usually there is a tendency to longitudinal growth by the
repeated division of one or more apical cells by means of
transverse septa, and also to the division of the cells of the
second degree by longitudinal septa. Lateral shoots are
very often formed. They are produced by the protrusion
of the wall of a somewhat older cell, and the subsequent
separation of the protuberance from the primary cell-cavity
by means of a transverse septum (PI. XXXVII, fig. 20).
These adventitious shoots exhibit the like forms of cell-
multiplication as the primary shoots, which they often sur-
pass in vigour (PI. XXXVII, fig. 22). In other cases there
is a manifest bifurcation of the fore-end of the prothallium
produced by the parting asunder and development of two
apical cells (PI. XXXVII, figs. 17, 21). When the cells

THE HIGHER CRTPTOGAMIA. 293

of the protliallium have reached the stage at which the
protoplasm of their contents clothes the inner wall in the
form of a thin layer, they have a manifestly vesicular ap-
pearance. I have often clearly observed their multiplication
by division (PL XXXVII, fig. 20). Mucilaginous threads
radiate from the nucleus.

However various the ramifications of the prothallium
may be at first, the final result is always the same. One
or more (five at the most) of the numerous shoots develope
themselves much more vigorously than the others in length,
breadth, and thickness. Their outline resembles to some
extent that of the prothallia of the ferns. The subse-
quently formed capillary roots of the prothallium are pro-
duced almost exclusively from their under side. Sexual
organs are mainly produced from these principal lobes;
they seldom occur on other parts of the prothallium.

The prothallia of Equisetum arvense, pratense, and
palu-stre, are distinctly disecious. The individuals which
bear antheridia produce them very plentifully, but yield
archegonia only in the rarest instances, and then upon late
shoots of the base of the prothallium. These may be con-
sidered as new individuals, by analogy to the processes
which spring from the marginal cells of old fern-prothal-
lia. The male prothallia do not attain the full size
of the females. They consist normally of only one or two
thickly fleshy expansions of cellular tissue, whose margins
bear the antheridia, and also some thin membraneous
barren shoots. Their chlorophyll contrasts with that of
the female prothallia by a manifest tendency to a yellow
colour. The deep-brown colour Avhich is assumed by
empty antheridia, imparts a diseased appearance to the
male prothallia at an early period.

The production of an antheridium is preceded by fre-
quently repeated division of one of the marginal cells by
means of septa inclined alternately in two directions (PI.
XXXVIII, fig. 24). The cells of the second degree divide
by radial longitudinal septa, and each of the three-sided
cells thus formed divide into inner and outer cells by septa
parallel to the axis of the organ. The latter become the
covering layer of the antheridium, and numerous chloro-

294 HOFMEISTEK, ON

phyll vesicles are spread over their inner wall. The me-
dian cavity of the cell is filled with a watery fluid. The
axile cells of the young antheridium form an oval group,
composed of four longitudinal rows of cells, and contain
finely-granular mucilage (PI. XXXVII, fig. 24). By
rapidly repeated division in all three directions of space
they are transformed into a mass of small tessellated cells,
which at first are in very close connexion with one another.
In each of them a flattened ellipsoidal cellule is formed
(PL XXXVII, fig. 25), in the interior of which a small
vesicle with less highly refractive fluid contents is some-
times visible (PI. XXXVII, fig. 26). The walls of the
firmly adherent cubical cells are now dissolved, and the
ellipsoidal cellules become free. A gelatinous mass, spread
over their inner wall, soon begins to be visible ; it forms
an imperfect ring parallel to the major axis of the ellipsoidal
cell. This is the first indication of the nascent sperma-
tozoa (PI. XXXVII, fig. 27). Numerous mucilaginous
granules remain for a long period in the middle point
of the cellule, even until the ripening of the antheridium.

The apical cells of the covering layer of the antheri-
dium, which are usually eight in number, contain little or
no chlorophyll. In the elongated antheridia of Eq. limosum
the cells adjoining these apical cells have also very little
chlorophyll (PL XXXVII, fig. 24). When the organ is
ripe the apical cells part asunder, and the cellules enclosing
the spermatozoa ooze slowly out.

These cellules are larger in Equisetum than in any other
known plant. In Uq. arvense their diameter attains — ".
When the vesicle is ripe the spermatozoon soon becomes
partly free, apparently by the distension and dissolution of
parts of the wall of the enveloping cell. The numerous cilia
on its thick fore-end commence their active oscillating motion,
by means of which the spermatozoon with the attached
vesicle moves rapidly about in the water on the slide. The
spermatozoon seldom becomes entirely free from its mother-
cell. When it does so, it has the form of a spiral vermiform
body, consisting of a mucilagino-gelatinous substance be-
coming dark-brown under iodine. Its fore-end, which is
the thicker of the two and slightly compressed laterally,

THE HIGHER CRYPTOGAMIA. 295

forms two narrow closely approximated turns of a (usually)
left-handed spiral. These turns alone bear the cilia.
During the rapid motion of the spermatozoon in water its
wider, final turn, upon which the cilia are wanting, ap-
pears to be somewhat reduced in size (PL XXXVIII, fig.
28), but when the spermatozoon is killed with iodine, it ap-
pears on the contrary considerably enlarged (PI. XXXVIII,
figs. 30 — 33). This remarkable phenomenon depends upon
an organization hitherto (as far as is known) unique in
the vegetable kingdom. The end of the spermatozoon bears
on the inner side of its ultimate turn a wide fin-like
process, consisting of a delicate membrane, which during
the motion of the spermatozoon glistens like the undulating
membranes of the spermatozoa of toads and Tritons.
When the motion becomes more active the membranous
margin becomes invisible like the cilia ; it is only clearly
visible when the vital activity of the spermatozoon is on
the decline (PI. XXXVII, figs. 30—33). The undula-
tions of the fin last longer than the oscillations of the
cilia. The hinder end of the spermatozoon appears still
somewhat pointed when the quiescent cilia of the fore-end
are already visible. The hinder end of the spermatozoon is
of a very delicate half- fluid consistence ; it attaches itself
easily to any object, and is then drawn out into long threads.
It often happens that a spermatozoon drags after it the
empty membrane of the mother-cell attached to one of
such threads, or that it fastens itself to a capillary root of a
prothallium (PI. XXXVIII, fig. 28J). Spermatozoa whose
motion, after many hours continuance, ends spontane-
ously, always exhibit a thin caudal appendage often of
very considerable length. The substance of their hinder
end has doubtless been drawn out into such threads, in
consequence of the spermatozoon having attached itself to
some body during its motion, and then torn itself away.
The substance of such spermatozoa exhibits, by the pre-
sence in it of vacuoles, manifest traces of a state of disten-
sion.* If the spermatozoa are killed with iodine they

* In the ' Veigleich. Unters.,' p. 101, I treated the whip-shaped elongated
form of the hinder end as a peculiarity common to the spermatozoa of Equisctum,
an assumption which was grounded upon the frequent occurrence of such
peculiarity.

296 H0FME1STER, ON

usually imrol themselves like a snail (PL XXXVII, figs.
31 — 33) ; it is but rarely that the individual turns remain
at a distance from one another, as is the case during the
motion. The motile cilia appear stiff and extended when
the spermatozoon is quiescent ; their direction is not radial
to the axis of the spiral of the spermatozoon, but is turned
backwards.

The mode in which portions of the spermatozoon remain
attached to the mother-vesicle is very various. Very fre-
quently the thick fore-end remains inside the spherical
vesicle, the lower turns protruding out of the fissure, and
causing by the oscillation of their cilia a restless reeling
motion of the organ and its mother-cell. More rarely the
fore-end is free and the hinder-end enclosed in the vesicle.
In such cases the motion is more regular and more rapid.
It more often happens that the cilia of the thickest end of
the spermatozoon protrude out of a fissure in the vesicle.
The continual rolling motion of such spermatozoa very much
resembles that of many infusoria,

I have seen the motion of the spermatozoa of Equisetum
arvense last for five hours. The sensitiveness of the sper-
matozoa to external influences appeared to me much less
than that of ferns. Water containing much gypsum, which
acted in a decidedly injurious manner upon the spermatozoa
of Asplenium septentrionale, had not the slightest effect upon
those of Eq. arvense, palustre, and limosum.

In Eq. limosum I found the first ripe antheridia five
weeks after the sowing of the spores (on the 1st of July),
in Eq. arvense thirteen weeks after (at the end of July) ;
in one case four weeks only after the sowing (at the end of
May). The number of the antheridia upon one prothallium
is sometimes as many as sixteen in Eq. arvense. The inner
wall of the cavity of antheridia which have discharged
their contents assumes a deep brown colour. The escape
of the cells enclosing the spermatozoa certainly takes place
spontaneously ; heaps of agglomerated dried mother-cells
of spermatozoa are often found at the apex of empty anthe-
ridia.

Numerous obstacles seem to interfere with the natural ger-
mination of the Equisetacese. Although I have often searched

THE HIGHER CRYPTOGAMIA. 297

for them, I have never found the prothallia of any species in
their natural state. Even under culture, the greater number
of the prothallia decay before the development of antheridia,
or are destroyed by insects, or by an overgrowth of
Vaucheriae, Oscillatoriea?, or proembryos of mosses. Before
1852 very few of the prothallia of Equisetum arvense which
I had cultivated lived beyond the fifth month after the
sowing. They were all of the male sex. In some I ob-
served the formation of a short, flat, lateral shoot, which
produced the rudiments of archegonia. This was the only
instance of departure from the disecious character which
ever occurred to me in the prothallia of Equiseta.

Those prothallia of Eq. arvense, variegatum, and palustre,
which produce archegonia never produce antheridia,*
They ramify to a much greater extent and become far more
vigorous than the male prothallia. A female prothallium
is normally a circular combination of from three to six
fleshy masses of cellular tissue, which bear very numerous
green crisp shoots of more delicate texture, and from a
quarter to half an inch in diameter. The form very much
resembles that of young plants of Antkoceros punctatus.

When male and female prothallia are produced from
spores sown contemporaneously, the archegonia of the
female prothallia appear much later than the antheridia of the
male ones ; the younger female prothallium would seem to be
sterile. The spores from which female and male prothallia
originate are exactly of the same size and quality. Exter-
nal circumstances seem to have an influence upon the
germinating prothallia. A dry place exposed to light
seems decidedly to favour the development of male pro-
thallia of Equisetum arvense. The spores of Equisetum
arvense and pratense when sown artificially produced prin-
cipally male prothallia, t and those of Equisetum palustre

* On the other baud Bischoff lias found the prothallium of Eq. sylvatium
beariug archegonia on its older portions and antheridia on its younger shoots.
([ Bot. Zeit.,' 1853).

f In 1S49, 50, and 51, I obtained only male prothallia, upon which rudi-
ments of archegonia appeared only at a late period, and then only upon adven-
titious shoots. In the summer of 1852 the number of male prothallia was
greater by about one half than that of the female ones. That summer seems to
have been especially favorable to the germination of Equisetum. Cultivated
specimens of Equisetum variegatum shed spores at the beginning of May.
About the middle of July female prothallia, which were present in great
numbers, developed small leafy plants.

298 HOFMEISTER, ON

(according to repeated experiments) only female pro-
thallia.

The archegonia are produced by the multiplication of
individual cells of the fore-edge of the thick, fleshy lobes
of the pro-thallium. After the commencement of the form-
ation of the archegonium the mass of cellular tissue to
which the organ is attached usually continues to grow
underneath it, so that the archegonia, like those of Pellia,
are afterwards situated on the surface of the prothallium.
A small, thin, membranous shoot of the prothallium is
usually formed near each archegonium (PI. XL, fig. 1).

The mother-cell of an archegonium which, like its neigh-
bours, contains chlorophyll, only differs from the latter by
its greater abundance of protoplasm. After its free upper
wall has become considerably curved, its first division takes
place by a horizontal membrane. The lower of the two
halves, which is entirely sunk into the tissue of the pro-
thallium, becomes the central cell of the archegonium, the
aperture of the latter being formed by repeated bi-parti-
tions of the upper half.

The first of these partitions takes place by a vertical
longitudinal septum. Another septum, also vertical and at
right angles to that just formed, appears immediately in
each of the two newly formed cells. The four cells sur-
rounding the central cell, which in the mean time has be-
come remarkably curved above, grow uniformly upwards,
and are at the same time divided by horizontal transverse
septa — exactly in the same manner as the four vertical-cells
of the fruit rudiment of a Jungermannia.* Thus a cylinder
is formed projecting above the central cell of the archego-
nium, composed of four longitudinal rows of cells (PI.
XXXVII, figs. 35 — 37). The upper pair of cells undergoes
considerable elongation, which afterwards takes place also
in the next adjoining pair, though in a less considerable
degree. The two lower pairs of cells of the neck of the
archegonium become elongated upwards, but hardly per-
ceptibly so; however, the incipient multiplication of the
cells adjoining the central cell extends to the two lower
pairs of cells, or at least to the lowest of them, the division
taking place by means of septa alternately perpendicular

* 'Vergl. Unters.,' pp. 18, 38.

THE HIGHER CRYPTOGAMIA. 299

and parallel to the Avails of the central cell. In consequence
of these divisions the central cell of the archegonium, when
fully developed, appears to be surrounded by one or two
epithelioid layers of cells (PL XXXVIII, figs. 1—4).

Inside the central cell, during the first stage of develop-
ment of the archegonium, there is formed a daughter-cell,
— the germinal vesicle. It originates round a secondary
nucleus, which makes its appearance in the apical arch of
the cell (PI. XXXVII, figs. 35, 36), sometimes as early as
the commencement of the formation of the transverse
septa of the two pairs of cells which form the neck of the
archegonium (PI. XXXVII, fig. 35). It grows gradually,
and during the formation of the archegonium displaces
more and more the contents of the central cell, especially
the second nucleus of the latter, which exists during its
formation (PI. XXXVIII, fig. 1). When the archegonium
opens, some granular mucilage, the last remnants of so
much of the contents of the central cell as has not been
absorbed in the formation of the germinal vesicle, seems to
be usually spread over the outer wall of the free spherical
cell (PI. XXXVIII, fig. 2).

The four longitudinal rows of cells which form the neck
of the archegonium now become disconnected at their edges.
An open canal is formed leading to the central cell and
traversing the longitudinal axis of the cylindrical neck.
This canal is the entrance to the archegonium. The four
elongated cells of its mouth bend semicircularly backwards
by which means the archegonium assumes a very strange
appearance ; it resembles an anchor with four flukes or arms
(PL XXXVIII, figs. 2, 3, 4, 6). The arched cells of the
mouth when they part asunder contain no solid matter ; the
few chlorophyll vesicles as well as the nucleus of the cell
have disappeared. The same is the case with the four cells
which support those last mentioned. The free neck of the
archegonium is transparent like glass.

There is far less difference between the structure of the
archegonia of the Equisetaceae and those of ferns than there
is between the antheridia of the same plants. The former
agree in all essential features with those archegonia of the
Polypocliacese in which the neck consists only of four longi-

/

300 HOFMEISTER, ON

tudinal rows of cells. It may be asserted that the Equise-
taceae on account of the disecious nature of their prothallia,
and the constant similarity of the structure of their arche-
gonia with that of the archegonia of the Rhizocarpeae,
especially of Pilularia, form the transition from ferns to the
Rhizocarpeae.

Male and female prothallia grow in the closest proximity,
their shoots often intermingling with one another. The
access to the archegonia, which is afforded to the sperma-
tozoa not only by every rain but also by every heavy dew,
is rendered still easier by the force with which, on the
spontaneousopening of over ripe antheridia,*the spermatozoa
still enclosed in their mother-cells — are ejected. I found
in the canal of a recently impregnated archegonium mucila-
ginous masses closely resembling defunct spermatozoa
(PI. XXXVIII, fig. 4).

The first visible change in an impregnated archegonium
is the closing of the lower end of the canal, caused by the
horizontal expansion of the cells of its walls (PI. XXXIX,
fig. 4, PI. XL, figs.l — 3). This closing is accompanied by
the further multiplication of the cells of the tissue surround-
ing the central cell. These cells divide repeatedly by lon-
gitudinal and transverse septa ; the division is particularly
active in the cells of the epithelium-like layer which adjoins
the central cell. The impregnated germinal vesicle has in
the mean time become somewhat larger. Its nucleus has
disappeared, and a layer of finely granular protoplasm
lines its inner wall (PI. XXXVIII, fig. 4). Now for the
first time — after the obliteration of the lower end of the
canal — the series of divisions commences by which the
embryo is produced.

The germinal vesicle is first divided by a septum inclined
to the longitudinal axis of the archegonium. The two
halves are again immediately divided by transverse septa
at right angles to those just formed. Sometimes the upper
and sometimes the lower of the two first cells of the rudi-
mentary embryo takes the lead in this division (PI. XXXVIII,
figs. 5, 6).

* It is at this time only that the small delicate crown represented by Thnret
('Ann. d. Sc. nat.,' iii S., vol. xvi, pi. 16, f. 1) is formed.

THE HIGHER CltYPTOGAMIA. 30 L

At this time or a little later the recurved cells of the
aperture of the archegoniuin shrivel and fall off. The four
elongated cells of the neck of the archegoniuin upon which
they are borne also lose their vitality. Their walls, so far
as they form the canal of the archegoniuin, assume a dark
brown colour.

The number of the archegonia of a vigorously developed
prothallium varies from twenty to thirty ; it exceeds there-
fore that of the anthericlia of even the largest male prothallia.
Usually more than one archegoniuin is impregnated. I
counted as many as seven embryos in one and the same
prothallium. The brown colour of the unimpregnated
archegonia extends not only over the walls of the whole
canal — which remains open — but also over the central cell
and its contents (PI. XXXVIII, fig. 3).

The first axis of the embryo (which remains undeveloped)
has its origin in a series of repeated divisions of the terminal
cell commencing in the three-sided cell which includes the
lower end of the embryo rudiment (PI. XXXVIII,
figs. 7—10 ; PI. XL, figs. 1—3). The cells of the second
degree divide at first only by longitudinal and transverse
septa perpendicular to the free outer surfaces (PI. XXXVIII,
figs. 7, 8 ; PL XXXIX, fig. 1) ; at a later period septa,
parallel to these surfaces make their appearance and form
inner cells. A similar cell-multiplication commences in the
one lateral cell of the 4-cellular- embryo-rudiment. The
lines in which the first septa of the lateral cell intersect are
parallel to the longitudinal axis of the archegoniuin (PI.
XXXVIII, figs. 7—10). A side shoot of the embryo is
thereby formed — the second axis of the germ plant, its
first leaf-bearing shoot. By the considerable growth in
thickness of the primary axis below the place of origin
of the secondary one, and still more by the upward curva-
ture of the latter during its development, the rudiment of
the secondary shoot is soon brought almost to the
apex of the globular cellular mass which now constitutes
the embryo — to within a small distance from the locus of
the lower end of the canal of the archegoniuin which is now
entirely obliterated (PI. XXXIX, figs. 4, 5).

Up to this stage the rudiment of the embryo may be

302 HOFMEISTER, ON

detached without much difficulty. Prom this time however
the cells of the surface of its primary axis become more and
more closely connected with the neighbouring cells of the
prothallium, whilst the latter — in some of which multiplica-
tion is continually going on — are more and more com-
pressed and at last entirely absorbed by the rapid increase
in size of the new plant.

The end of the secondary axis of the embryo resembles
at an early period both in its form and in the mode of mul-
tiplication of its cells the terminal bud of a shoot of a
developed Equisetum. The comparatively large apical cell
and the ladder-like arrangement of the cells of the second
degree are clearly distinguishable in the sharply conical
wart of cellular tissue (PI. XXXIX, fig. 4). As soon as
the bud has assumed this form, it produces its first leaf,
which like those of the developed plant is a closed, annular
sheath of uniform height {a, fig. 4, PL XXXIX). The
margin of this sheath is elongated upwards by contempo-
raneous division of its cells by means of septa inclined
alternately inwards and outwards, and after some time it
forms three lobes, which at first are blunt, but soon become
pointed (PI. XXXIX, fig. 5).

Contemporaneously with these three pointed processes of
the first sheathing leaf the first adventitious root of the
germ plant becomes visible. Originating in the multipli-
cation of a cell of the inner tissue of the primary axis, it
appears at first in the shape of a small, semicircular knob on
that side of the embryo which is turned away from the
secondary leafy shoot (PI. XXXIX, fig. 5). The root
grows in length by the multiplication of a cell of the interior
of its apex like the root of the developed plant, and pene-
trates vertically downwards into the tissue of the prothallium
(PI. XL, figs. 2, 3). At last it breaks through the latter and
makes its way for some depth into the soil. A short time
afterwards the upward growing leafy shoot is sent forth from
the prothallium. It consists of a small number, from ten
to fifteen, of elongated internodes. All its sheathing leaves
have three teeth, a rule which applies to Equisetum arvense,
E. pratense, and E. variegatum.

After the prothallium has sent forth the root and the

THE HIGHER CRYPTOGAMIA. 303

leafy shoot, vascular bundles are formed in the interior of
the two organs : in the stem there are three arranged in a
narrow circle ; in the root one single axile bundle. In the
first node of the germ -plant, at the place where the first
leafy branch and the first adventitious root branch off from
the primary axis, all the cells into which the vascular
bundles of both unite, are transformed into short annular
and spiral cells, forming a closed ligneous mass without
pith (PI. XXXIX, fig. 6). The primary axis of the embryo,
which is far less developed in the Equisetaceas than in the
ferns and Rhizocarpeas, and which now stands at the side of
the germ-plant, remains devoid of vessels. Its cells, which
now contain much chlorophyll, become elongated upwards.

When the first leafy branch has reached a certain stage
of development, an adventitious bud is produced in the in-
terior of its cortical tissue by the multiplication of a cambial
cell of its base, at the elevation of the solid ligneous
mass of the first node. This bud is situated on that side
of the leafy shoot which is turned away from the primary
axis of the germ plant and below the depression formed by
the two lobes of the first sheath (PI. XXXIX, fig. 6). In
its position as well as in its mode of development it corres-
ponds entirely with the adventitious buds, by which all the
ramification of the developed Equisetum is effected. It
grows rapidly and vigorously and breaks through the bark
of its mother-shoot into the open air. It is distinguished
from the first leafy axis by having sheathing leaves with
four teeth, and at first also by its pale yellow, ivory-like
colour. The new shoot, which is far more vigorously
developed than the first shoot, is the second link in the
series of shoots originating from the adventitious buds of
the lowest sheaths. It is by means of these latter shoots
that the vigorous shoots with many-toothed sheaths and more
ample ramifications are produced from the delicate primary
stem which bears leaves with three teeth. The basal ad-
ventitious buds of the above vigorous shoots at last become
fruit-bearing stems.

Sometimes the third, and if not the third, one or more
of the subsequent principal adventitious buds (by which
the duration of the germ-plant is secured) assume in the

304 HOFMEISTER, ON

course of their development a lateral, or downward direc-
tion, passing into the soil, and thus forming the first hori-
zontal subterranean rhizome of the Equisetum. The
sheathing leaves of this subterranean axis— which produces
a large quantity of adventitious roots — have also four teeth.
The shoots however which proceed from the bases of their
sheaths, of which some grow up to the light, and others
pierce vertically downwards to a great depth in the soil, are
considerably more vigorous than all the previous ones and
bear sheaths with five teeth.

Adventitious buds are produced at the bases of the
upper sheathing leaves of the first shoots of the germ
plant. In Equisetum arvense one or two only and these
rarely and irregularly break through the bark of the
mother-shoot, and when developed form leafy branches of
very limited longitudinal growth. The limited number of
whorls (amounting on the first axis to barely three, and on
the succeeding axes to not more than four), forms a
striking contrast with the rich ramification of the vege-
tative shoots of old individuals. The formation of dwarf
shoots occurs only rarely and exceptionally on those
branches.

The development of the germ-plant under favorable
circumstances is very rapid and vigorous. Germ-plants of
Equisetum arvense, produced from the prothallium in the
first week in June, formed by the beginning of August
seven generations of shoots, the last of them being then a
foot high, and \\'" in diameter, though bearing only four-
toothed sheaths. The strong side-shoots of subterranean
rhizomes became visible about the end of August.

The reproduction of the EquisetaceEe from spores long
remained a mystery. Vaucher* in the spring of 1822
first brought forward the results of experimental sowing
of the spores, and he was followed by J. G. Agardh.f
They both saw only the first stages of development of
the prothallia, which Agardh described as cotyledons on
account of their two-lobed form. In the following year
Vaucher published some observations which gave a full

* 'Mem. Soc. de Geneve,' i, (1817) p. 329.
t ' Mem. du Musee d'Histoire Nat.,' vol. ix.

THE HIGHER CRYPTOGAMIA. 305

•

account of the external phenomena of the germination.
Vancher found* that spores of Eq. Telmateia and palustre,
when sown in flower-pots, became swollen, and divided at
the apex first into two, and then into several lobes. These
lobes sent forth rootlets which affixed themselves to the
ground, and ultimately formed bright green patches some-
times as much as a line in diameter, and resembling a
small Aneura. They remained in this condition for about
two months without growing perceptibly. At last a
green point grew out from the middle of the patch, which
point, as it became larger, exhibited a frill at its base, then
a second, and then a third frill, from the apex of which the
young stem arose. Vaucher distinguished the two kinds
of roots of the prothallium and of the embryo ; he stated
that the first formed roots were numerous, although thin
and stunted ; but that a vigorous root was produced from
the stem of the young Equisetum, and penetrated perpen-
dicularly into the ground.

Vaucher's observations remained for some time quite
unsupported. In 1826 Bischoffs experiments only re-
sulted in the production of prothallia, all of which after-
wards decayed. He showed, however, clearly, f that the
processes described by Agardh and Vaucher as cotyledons,
were only an imperfect, or intermediate germ -growth (a
proembryo or prothallium), which, as in most other cryp-
togenic plants, afterwards became transformed into a
true embryo. In the autumn of the same year Bischoff
supplemented his observations by publishing the result of
his examination of some germ-plants of Eq. palustre, found
in the autumn of 1827, in their native habitats. % He
observed that the young germ-plants burst forth from the
interior of the prothallium, and he disproved Vaucher's
statement, — viz., that the root which penetrates into the
earth is afterwards transformed into the rhizome — by show-
ing that at a very early period the germ-plant produces
lateral shoots, whose growth from the commencement fol-
lows a horizontal or downward direction. He noticed also

* 'Mem. d. Musee.,' vol. x, 3823, p. 429.

+ ' Kryptog. Gewachse,' i. Number?, 1828, p. 43.

% See''N. A. A. C. L.,' vol. xiv, p. 785.

20

806 HOFMEISTER, ON THE HIGHER CRYPTOGAMIA.

•

the development of more than one germ-plant out of the
same prothallium. At that time he quite overlooked the
sexual organs. Thuret (' Ann. d. Sc./ iii ser., 1849, vol. V,
p. 5,) gives the first account of the antheridia of Equi-
setum, and the discovery of the archegonia seems to be
clue to Bischoff. Mettenius mentions (' Beitrage zur Bot/
Heidelberg, 1850, p. 22), that archegonia resembling the
defunct archegonia of ferns were found upon a small piece
of a prothallium which he saw in Bischoff's possession. Milde
in 1850 ('Linnaea/ xxiii, p. 545), gave a more complete
account of the structure of the antherida and spermatozoa.
A little later I myself explained the development of the anthe-
ridia and spermatozoa, and figured the first stages of deve-
lopment of the archegonia (' Vergl. Unters.' Leipz., 1851, p.
102, PI. xx. fig. 62). Soon afterwards, Milde also observed
the neck of the archegonium, but without knowing what it
was ('N. A. A. C. L.,5 xxiii, 641). In 1852 I observed
the development of the embryo ('Flora,' 1852, p. 385),
and almost at the same time Milde discovered arche-
gonia, and he published his observations soon after mine
('Flora,' 1852, p. 497). I made some further remarks
upon my previous observations in the fourth volume of the
' Transactions of the Royal Society of Saxony/ p. 16S.

CHAPTER IX.

0PH 10 GLOSSED.

The germination and development of ' Botryehium Lunaria Siv.

The Moonwort germinates underground. Germ-plants*
are sometimes found in the neighbourhood of full-grown
individuals in places where the plant is common. They
are not unlike torn fragments of branched roots of the
plant itself (PI. XLII, figs. 2 — 5), but upon careful exami-
nation they are found to be organically closed at all ends.
At the point of junction of the roots, a prominent knob
is found (PI. XLII, figs. 4, 5). A microscopical analysis
of the latter leads to the discovery of a bud buried in
a deep, almost closed depression. In September, IS 54,
Irmisch and I discovered at a depth of from one to three
inches under the surface of the earth, not only a series
of productions undoubtedly transitional between germ-
plants and full-grown Botrychia, but also germ-plants, to
which the prothallium was still attached. The prothallium
of Botrychium (PI. XLI, fig. 5), is an oval mass of firm
cellular tissue, whose larger diameter does not exceed half
a line, and is often less. It is light brown on the outside,
yellowish-white on the inside, and furnished on all sides
with scattered, rather long, capillary roots. The cells,
whose size diminishes from the middle of the prothallium
towards the periphery, are filled with large and small lumps

* The germ-plants upon which these observations were made came from the
neighbourhood of Sondershausen. I am indebted to my friend Professor
Irmisch for them.

308 HOFMEISTER, ON

of a semi-transparent substance, which is not rendered
blue by iodine. On the side turned towards the surface
of the earth the prothallium mostly produces antheridia,
and on the opposite side archegonia. The former have the
appearance of cavities in the mass of the prothallium, which
open outwards with a very narrow mouth (PI. XLI, figs.
5, 6, 106.) The spermatozoa are hardly distinguishable
from those of the Polypodiacese, except in being half as
large again as the latter. The walls of empty antheridia are
coloured light brown, and are covered with a granular sub-
stance. The archegonia (PI. XLI, figs. 5, 10*), are en-
tirely buried in the prothallium, but agree in other respects
with those of the ferns. Spores sown artificially swelled to
twice their natural size, but underwent no further change.
The membrane of a spore thus swollen was found attached
to a prothallium, and was recognisable by the three promi-
nent ridges of the outer surface, which meet at angles of
120° (PL XLI, fig. 7).

The position of the embryo with regard to the prothal-
lium differs widely from what occurs in the Polypodiaceae
and Rhizocarpese. JBotrychium in this respect is allied to
those vascular cryptogams, whose prothallium, like that of
the Ophioglosseae, is devoid of chlorophyll (Isoetes, Selagi-
nella). The punctum vegetationis of the embryo lies near
the apex of the central cell of the archegonium. The first
roots originate underneath it near the base of the archego-
nium (PI. XLI, fig. 6*; PI. XL1I, fig. lb). In con-
sequence of the downward direction of the mouth of the
archegonia, the embryo has to turn half round in order to
give its bud an upward direction, so that the prothallium
is found attached to it laterally. The youngest germ-
plants found attached to prothallia, exhibited at least
two roots, and also near the punctum vegetationis, a more
or less developed hemispherical or oval knob (PI. XLI, figs.
8 — 10). The outside of the latter (on account of the
colour) bears only a distant resemblance to the roots : its
internal structure differs widely from theirs : the hemi-
spherical body consists of wide parenchymatal cells, which
become gradually smaller and flatter towards the outer
surface : a rudimentary vascular bundle consisting, with

THE HIGHER CRYPTOGAMIA. 309

the exception of vessels, only of thin-walled prosenchymatal
cells, extends from the nearest vascular bundle of the root
for a short distance into the mass of cellular tissue. *This
structure, and also the position of the knob on the germ-
plant, correspond exactly with the structure and position of
the organ found on the embryo of the Polypodiaceae and
of other vascular cryptogams, which I have treated as the
continuously developing primary axis of the embryo — with
the primordial tissue of the embryo, which bears on its lateral
surface the formative cells for further development.*

In Botrychium this primary axis, if unusually developed \
in thickness, may protrude laterally out of a fissure of the
prothalliuin. ,. The roots originate above the knob, the
oldest and longest of them being the nearest to it. The
direction of the roots is usually opposite to that of the
knob. The punctum vegetationis — the growing end of the
secondary axis of the embryo-— occupies the highest point
of the germ-plant (PI. XLT, fig. 10* ; PI. XLII, fig. lb).
This bud, which consists of a flatly-conical group of thin-
walled cells, is situated at the base of a narrow, short, trans-
verse fissure in the blunt apex of the germ-plant, i. e., the
narrow opening of the vaginated scale-like first frond
of the latter (PI. XLII, fig. I6). Germ-plants less deve-
loped than those above described were also found in quan-
tities (PL XLII, figs. 2, 3). They consisted only of the
globular knob, and the first or the first and an incipient
second root. The punctum vegetationis lay immediately
on the upper surface of the knob. In these plants no
trace of the prothallium could be perceived. They were
probably of the same age as those above mentioned, but
stunted and arrested in their development.

The nature of the punctum vegetationis of the germ-plant
of Botrychium is a matter of special interest, inasmuch as it
must afford material assistance in deciding which of two
opposite opinions is the correct one. Roperf assumed that
the true stem rises vertically, but owing to the non-deve-
lopment of the internodes, imperceptibly ; that it produces
two leaves or fronds every year, whose stalks grow together

* ' Griesebacli Jahresber.,5 1S52, p. 404.

f 'Linusea,' vol. i, p. 460; 'Flora Mecklenbergs,' vol. i, p. 110.

310 HOFMEISTER, ON

upwards for some distance, and consequently enclose the
true apex of the stem, together with the bud which consists
of two leaves corresponding with the former in every
respect. Presl (' Tent, pterid,' suppl., p. 41) has modified
this view. He considers the fertile and the sterile frond as
only segments of one and the same leaf, the under segment
of which becomes fruitful, whilst the upper remains leaf-
like. Mettenius (' Farrne des botan. Gartens zu Leipzig,'
1856, p. 119) and Roper also quite lately (' Bot. Zeit./
1859, p. 244) have arrived at the same opinion. Braun,*
on the other hand, asserts that " the cellular body from
which in Ophioglossum the leaves are produced cannot be a
special sheathing leaf, nor even of the nature of a stipule or
ligule, but it is a cellular body which surrounds the centre
of growth, and inside which the leaves are formed in suc-
cessive spirals, and there remain. Within this body each
leaf forms its own cell, which enlarges with the growth of
the leaf, and becomes gradually elevated in a conical form,
and ultimately pierced in a sheath-like manner. The fruc-
tification of Ophioglossum is axillary ; it is the only leaf
•which comes to perfection from a bud in the axil of a sterile
leaf. .... Botrychium does not possess the enve-
loping cellular body, but on the other hand, in this genus,
the leaves form their own sheaths." I have, myself at-
tempted to show that the most striking feature sug-
gested by Braun exists also in Botrychium, for I assumed
that each of the contemporaneously developed pairs of
fronds originated in an entirely closed cavity, being the base
of the next older pair of fronds. According to this the
stem of Botrychium would be a sympodium of the basal
portions of successive yearly shoots. f Schacht also agreed
in this view when he asserted that Botrychium was repro-
duced only by adventitious buds.f

These notions, however, are founded in an error, easily
accounted for by the want of transparency of the tissue.
This error consists in omitting to observe the very narrow
points of junction of the cavities of the pairs of fronds as

* 'Flora,5 1S39, p. 301.
t 'Vergl. Unters.,' p. 88.
' ' t 'DiePflanzenzelle,5 p. 304.

THE HIGHER CRYPTOGAMIA. 311

well inter se as with the atmosphere, and with the (hitherto
entirely unobserved)* depressed empty space above the
vegetative centre or terminal bud of the stem.

The second and the third frond also of the germinating •
Botrychium are scale-like, of a whitish colour, and composed
of elongated cells containing very little solid matter ; never-
theless the second frond sometimes, the third always, have a
greenish tip (PI. XLII, fig. 9), which is the first indication
of the lamina of the frond. In the fourth frond this green
portion is more fully formed : it contains on either side two
or three feathery flaps, between the lowest of which the
rudiment of the fertile frond makes its first appearance in
the form of a hemispherical protuberance. It produces only
a few, usually two, simple ramifications. This pair of
fronds, after breaking through the sheathing portion which
forms the principal mass of the third frond, rises above the
surface of the earth during the next vegetative period, and
represents a diminutive moon-wort, not differing essentially
from the older ones. It is not yet ascertained whether,
during the subterranean growth of the germ-plant, one only
of the scale-like fronds is developed yearly, as is the case
with full-grown plants. It is very unlikely that such should
be the case : the formation of the first, second, and third
fronds probably takes place in the first vegetative period of
the germ-plant, which consequently would develope in the
second year the first green frond, and at the same time the
first spore-bearing frond.

Each new pair of fronds makes its appearance near the
almost smooth end of the stem of the full-grown plant in
the form of a minute flatly-conical protuberance. The
basal sheathing portion is first developed by active multi-
plication of the cells, especially in the direction of a plane
passing through the median line of the organ and radial to
the longitudinal axis of the stem, so that the rudiment of
the pair of fronds destined to be developed in the third fol-
lowing spring covers the terminal bud of the stem, like the
cotyledons of a liliaceous plant. The apex of the frond-

* This circumstance was not noticed by Presl and Mettenius, but was ob-
served by Roper in a paper which appeared after the publication of the above
observations. (See ■ Bot. Zeit.,' 1859, p. 242.)

312 HOFMEISTER, ON

rudiment is at this time almost hemispherical, without a
trace of a division. The fore-edge of the base of a frond is
not in organic connexion with the tissue of the end of
the stem upon which it rests ; at this place there is a low
but tolerably wide fissure (PI. XLII, figs. 10*, 1 1). In the
second summer a flat cellular mass first makes its appear-
ance out of the rounded apex of the frond-rudiment : this
is the rudiment of the sterile frond, upon which the lowest
pinnae of the lamina first make their appearance. Whilst
the next four, five, or six segments of the sterile frond are
making their appearance on the continually-elongating end
of the cellular body, (and frequently also at an earlier period),
a button-shaped cellular protuberance becomes visible close
underneath, and almost between, the oldest pinnae of the
sterile frond ; this is the rudiment of the fertile frond (PL
XLII, fig. 2). So far the pair of fronds is developed up to
midsummer of the second year. The further development
remains dormant until the following spring. During this
time the transverse fissure which divides the fore edge of
the sheathing base of the frond from the underlying tissue
continues still open for a short space ; it forms a direct
communication between the hollow spaces which enclose
the pairs of fronds for the second and third following years
and the terminal bud. The transverse fissure first disap-
pears during the vegetative period in which all the parts
of the pair of fronds are completed,— twelve months be-
fore the final appearance above ground, — whilst the rami-
fications of the fertile frond proceed from the protuberance
in front of the points of insertion of the lowest segments of
the barren frond. The development, as in the barren frond
and in the fronds of ferns, is centrifugal.*

Development of the vegetative organs of Ophioglossum
vulgatum. — The thick covering of cellular tissue which sur-

* Roper has made an interesting observation ('Bot. Zeit./ 1859, p. 257),
viz., that plants of Botrychium Lunaria growing in loose sandy ground sometimes
exhibit lateral ramifications on the subterranean stem, originating, it would
seem, from the formation of adventitious buds underneath the base of the frond.
The growth of these lateral branches resembles to a great extent that of germ-
plants, inasmuch as at first they form scaly leaves only, and ultimately, when a
leaf first appears above ground, fertile and barren segments are formed contem-
poraneously.

THE HIGHER CRYPTOGAMIA. 313

rounds the young undeveloped frond of Ophioglossum is
not entirely closed. On that side of it which is turned to-
wards the next older frond (which has broken out of its
covering) it exhibits a narrow opening surrounded by a
tuft of jointed hairs constituting in this plant the only
appendicular organs of the epidermis (PI. XLI, fig. I). On
the inside also the hollow space which covers the oldest of
the enveloped fronds is not closed. A narrow cylindrical
passage leads from its fore-side into the cavity which en-
closes the next younger frond, and from this in like manner
into the cavity in which the frond destined for development
in the third following year is produced ; and lastly the
latter is in open communication with the narrow space
above the flat end of the stem (PI. XLI, figs. 1, 2).

The fronds surround the end of the stem in a | left
handed spiral, as may be clearly seen in transverse sections
of the stem at the place where the vascular bundle which
passes from the cylinder of vascular bundles obliquely up-
wards to the fronds, traverses the cortical parenchyma
(PL XLI, figs. 3, 3*). The young frond makes its appear-
ance near the depressed, almost flat end of the stem, in the
form of a slender conical knob, from the fore side of which
a fleshy flat stipule-like excrescence, as in Marattia, is pro-
duced (PL XLI, fig. 2h). This cellular mass developes in
breadth more vigorously than the part of the frond which
is situated above its place of attachment. It embraces
about two fifths, and the frond about one third, of the zone
of the stem upon which they both stand. The axile stipule
attaches itself by its fore edge to the front surface of the
stipule of the obliquely-opposed next older frond and at
its lateral edges it amalgamates immediately with the
stipules of the adjoining older fronds to the right and left,*
which stipules have already amalgamated inter se, and pro-
trude considerably beyond the youngest frond behind which
they stand. By this means the hollow space is formed
which encloses the young frond. The walls of the cavity
are derived from four different sources. The wall which is
turned towards the front surface of the enclosed frond con-

* The second and third, reckoned backwards from the frond of which we
are speaking.

314 HOrMEISTER, ON

sists, in its lower portion, of the hinder side of its own par-
ticular stipule, and in its upper portion, of the stipule of
the next older frond. The greater part of the wall which
is turned towards the hinder side of the frond, is composed
of the front surface of the stipule of the third youngest
frond, and the remainder of the latter wall is formed of
the front surface of the stipule of the second youngest frond.
The different stipules amalgamate at all points of contact
with the exception of those points which are coincident
with a line perpendicular to the apical cell of the stem.
Consequently there remains a very narrow open canal
leading to the apex of the stem into which the different
cavities enclosing the fronds debouch by a small opening
(PL XLI, figs. 1, 2).

If a careful section be made through that part of the
stem in which the punctum vegetationis lies, the three-
sided apical cell of the stem is seen at the base of the
canal* leading to the punctum vegetationis, surrounded by
the youngest secondary cells (PI. XLI, fig. 4). Longitu-
dinal sections through the terminal bud (PL XLI, fig. 2s).
exhibit most distinctly the deep depression of the apex of
the stem into the prematurely developed peripheral tissue ;
a phenomenon which, here as elsewhere, depends upon an
early vigorous diametral cell-multiplication accompanied
by a very slight almost obsolete longitudinal cell-multipli-
cation.

The course of the vascular bundles of Ojjluof/lossum is
simple ; they form a cylindrical net, one of the meshes of
which corresponds with each frond, and sends out to the
frond a vascular bundle from its apical angle. Frequently,
however, all the cellular tissue which fills up the
meshes is transformed into scalariform vessels, so that the
stem then, for considerable distances, exhibits a closed
cylinder of vessels. Sometimes this condition is found only
in one longitudinal moiety of the stem, whilst in the
other the distribution of the meshes of the vascular bundles
is the same as in the neighbourhood of buds. Roots — re-
markable for the slight development of the root-cap — spring

* The canal is somewhat enlarged above the punctum vegetationis.

THE HIGHER CRTPTOGAMIA. 315

from the bundles adjoining the sides ~of the meshes of the
reticulated vascular bundles of the stem ; their position
with regard to the fronds is not a definite one. Ojj/iio-
glossum vulgatum (like 0. pedimculosum), is often repro-
duced by root-buds. The new plant is reproduced by
the multiplication of a cambial cell of the vascular bundle
which traverses the longitudinal axis of the widely-creeping
adventitious root, and is at first concealed in the cortical
parenchyma of the root. However, this mode of repro-
duction is not so essential for the economy of the plant as in
0. pedunculosum , a species which may be called mono-
corpous, inasmuch as its shoots usually die off when they
have brought forth sporangia : its perennial duration rests,
it may be said, exclusively upon the adventitious shoots of
the roots.*

The appearance of fertile fronds on the front surface of
the sterile ones is the same in Ophioglossum as in Botry-
chium, and justifies the same conclusion, viz., that the
fertile frond is a shoot of the sterile one.

Mettenius has published some observations upon the
germination of Ophioglossum (f Farrne des Leipz. Botan.
Gartens,' Leipzig, 1856,' p. 119). He found the sub-
terranean prothallia and germ-plants of Ophioglossum
jjendunculosum growing in the neighbourhood of the
mother-plants. Artificial sowings of the spores were un-
successful. The youngest prothallia which he found con-
sisted of a small globular knob, of from ^] to 1^ lines
in diameter, from which a conical prolongation of about
twro lines in length proceeded. The delicate-walled cells of
the parenchymatal tissue of this knob were filled with
amyloid granules : the superficial cells, and the capillary
roots proceeding from them, were already dead. The
formation of the knob was thus already ended, and the
growth of the prothallium limited to the prolongation,
whose cells filled with thick protoplasm, were in an active
state of division. In older prothallia the prolongation
attains a considerable length, as much as two inches. Its
growth arises from the repeated division of a single apical
cell by means of oblique septa. The daughter-cells ap-
* Like Pi/rola unifiora. See Irmiscli in 'Plot. Zeit.,' 1856.

316 H0FMEISTER, ON

peared in some prothallia to be arranged in three rows.
Slender prothallia consist throughout, even in the cylin-
drical portion, of tissue homogeneous with that of the knob.
In thicker prothallia a string of cells in the axis of the
cylinder attains to double the length of the cells of the
peripheral tissue. The former contain only a few
amyloid granules ; the latter are quite filled Avith them.
Dichotomous prothallia were but rarely seen, and a repe-
tition of the division of one of the branches was of still rarer
occurrence. When in a normal position the apex of the
prothallium tends to grow to the surface of the ground. As
soon as it reaches the light it assumes a green colour, the
amyloid granules receiving a covering of chlorophyll.
The effect of light seems to be to limit the further growth
of the prothallium : the protruding apex either dies, or
becomes flattened, or divides into two or three small lobes,
which develope themselves no further. Antheridia and
archegonia are met with on the same prothallium without
any definite number or arrangement. They are either
altogether wanting on the knob, or are present in small
numbers at the base of the prolongation. They are always
plentiful upon the latter. Slender prothallia produce more
antheridia than archegonia : in vigorous prothallia the
archegonia are most numerous. The development of the
sexual organs progresses from the base of the prothallium
towards its apex. Their structure entirely resembles that
of the same organs in Botrychium. The youngest ob-
served embryos are ellipsoidal bodies consisting of few cells.
That end of the rudiment of the embryo which is turned
towards the apex of the prothallium forms the first leaf; the
opposite end forms the first adventitious root. Both cause
an expansion of the surrounding tissue ; the leaf makes itself
a passage for a longer or shorter distance into this tissue,
sometimes penetrating, with a turn downwards, as far as the
knob, and growing through it. After its egress the leaf is
enclosed by the drawn-out portion of the prothallium. Its
fore-surface is turned towards the apex of the central cell of
the archegonium, a circumstance in which it agrees with
Botrychium, and differs from the Polypodiacese and Rhizo-
carpeee. The first root, as soon as it is formed, bends out-

THE HIGHER CRYPTOGAMIA. 317

wards, and pierces through the proth allium. Towards the
base of the central cell of the archegoniura the rudiment of
the embryo is developed into a rounded inconspicuous
swelling, consisting of wide cells filled with amylum.
This swelling is the continuously-developing primary axis
of the embryo.

CHAPTER X.

PILULARIA GLOBULIFERA AND MINUTA ; MARS1LEA

PUBESCENS.

The fruit of Pilularia is the transformed end of a furcate
branch, which is apparently produced in the axil situated
between one of the long thin fronds and the" principal axis,
and which in Pilularia minuta is usually a lateral bud
situated in one of the normal bifurcations of the stem. In
P. minuta it forms when in the very young state, a globular
mass of delicate homogeneous cellular tissue flattened at the
apex. An outer layer of cellular tissue, composed of four
layers of cells, surrounds two lenticular cavities which are
separated from one another by a thick septum. The inner
side of the outer wall bears the rudiments of sporangia. In
this species, even at this early period of development, no
traces of the junction of the amalgamated parts are visible
at the apex of the fruit (PI. XLIV, fig. 8). In the young
fruit of Pilularia globulifera the commissures of the four
delicate cross septa of the divided chambers exhibit very
manifest lines of junction, which, in the half developed fruit
(upon the outer wall of which numerous hairs are formed)
are still unclosed. Here also clavate masses of cellular
tissue, the first rudiments of the sporangia, spring out of
the inner wall of the outer surfaces of these chambers. In
Pilularia minuta there are only two or three of these masses,
in other species as many as eight vertically one over the
other. The wider end of the very young sporangia, which
is borne by a short thick stem, exhibits a large central cell
surrounded by a double layer of smaller cells (PI. XLIV, fig. 3).

HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 319

The central cell divides into two (PI. XLIV, fig. 4),
and each of the cells thus formed divides repeatedly
into two cells turned towards all three directions of space.
The cells of the two enveloping layers meanwhile divide only
by septa perpendicular to the outer surface. The sporan-
gium thus becomes a globular mass of large cells enclosed
by a double layer of smaller tubular cells, and borne upon
a very short cylindrical stem. The larger cells — the
mother-cells of the spores — isolate themselves during the
farther growth of the fruit ; the cells of the inner layer of
the covering produce in the mean time numerous free small
cells in their interior, which, as the membranes of their
mother-cells divide, escape from the latter into the inner
cavity of the sporangium (PI. XLIV, fig. 5) : at a later
period they are absorbed. Each spore-rnother-cell when it
has become free divides contemporaneously into four
daughter-cells which are the special mother-cells of the
spores. This stage of development is attained at an earlier
period by the lower sporangia than by the upper ones.
After the walls of the special mother-cells have increased
considerably in thickness, a spore is produced in each of
them (PI. XLIV, figs. 6, 10, 11). Up to this point all
the sporangia behave alike. From this time however the
further development of the lowermost sporangium of each
compartment of the fruit differs very materially from that
of the others. In the sporangium in question the special
mother-cells and spore- cells (which are arranged in sets of
four) all die slowly off except one (or two). The spores of
the one set which remains soon become free by the absorp-
tion of the walls of the mother-and special-mother-cells, and
assume a globular form. At first all four increase rapidly
in size (PL XLIV, fig. 7); their walls then become much
thickened but unequal-sided, so that the globular inner
cavity of the young spore becomes excentric (PL XLIV,
figs. 6, 11). The growth of one of the spores soon exceeds
that of the others. The former alone continues to develope
itself, whilst the growth of the others is arrested, and being-
pushed aside — like the remains of the mass of special
mother-cells — by the one growing spore, they are soon dis-
solved. When the fruit is ripe the large spore occupies the

320 HOFMEISTER, ON

entire cavity of the sporangium, which in the mean time
has become much enlarged. The shape of the spore changes
during its growth from that of a globe into a short pear-
like form (PL XLIV, figs. 12, 13, 14), and from the latter
into that of an oval, slightly constricted at the equator
(PI. XL1II, fig. 1). In its narrow end, which is turned
towards the apex of the sporangium, its nucleus is found
embedded in a mucilaginous layer which clothes the wall.

By the time the spore has become globular a transparent
outer membrane is distinguishable, differing from the deli-
cate inner wall. Afterwards a second membrane, composed
of prismatic closely appressed columnar cells, is formed
upon this inner layer of the outer membrane. These
columnar cells are very short at the base of the spore, much
longer in its upper third part, but altogether wanting at
the apical point of the spore. The ripe spore is clothed by
a thick gelatinous layer, the component parts of which are
also prism-shaped. This layer also does not cover the apex
of the spore, to which there is access by a funnel-shaped
passage through the gelatinous layer (PI. XLIII, figs. 1, 7).
The glassy inner layer of the outer membrane extends
beyond the apex of the ripe spore in the form of a
conical arch, open at the tip. It appears torn into nu-
merous— in Pilularia glohullfera as many as eight — three-
sided shreds.

The spores which originated in the upper sporangia
are transformed jointly and severally into much smaller
globular spores, exhibiting at their apices three fissures
of the exosporium, meeting at angles of 120°. These
fissures point out the edges of contact of four spores
inside a set of special mother-cells. In Pilularia minuta
the small spores also are clothed wTith a gelatinous layer,
which is wanting in those of P. globulifera. No trace
of a nucleus is visible either in the large or small spores
when ripe. The contents of both consist of a mass of
albuminous fluid containing numerous firm granules of a
substance rendered brown by iodine, as well as oil-drops
and starch -grains. In the large spores the starch-grains,
which are of a great size, exhibit manifest lamination, and
a central cavity with fissures proceeding from it. In the

THE HIGHER CRYPTOGAMIA. 321

•small spores the starch grains are exceedingly small and
exhibit no structure.

The ripe fruit of PiMaria glohdifera splits into four
valves. The sporangia burst by the vast expansion of the
internal jelly produced by the dissolution of the special
mother-cells ; the jelly becoming distended by the absorp-
tion of water. Numbers of large and small spores thus
become free.

A few hours after this process the germination of the
large spores commences. The first indication of this is the
appearance of a lenticular agglomeration of finely granular
protoplasm on the inner side of the apex of the spore,
underneath the pyramidal arch formed by the triangular
lobes of the inner membrane. This mass of protoplasm is
soon clothed with a membrane, and then constitutes a very
flat cell with a circular outline (PL XLIII, fig. 2). Shortly
afterwards, before the expiration of twenty-four hours, the
conical cavity formed by the lobes of the glassy layer of
the outer spore-membrane appears to be filled by a cellular
body, consisting of a large central cell surrounded by a
simple layer consisting of a few tabular cells (PI. XLIII,
ligs. 3, 3*, 5). I did not succeed in finding the interme-
diate stages between this condition and the one previously
described, but I do not doubt that this cellular body is pro-
duced by repeated bi-partition of the lenticular cell which is
arched above. The lenticular cell may be first divided into
four, by the production of septa cutting one another at right
angles. It is probably one of these four cells, which—-
being divided by a diagonal septum inclined inwards — gives
rise to the formation of the central cell, which latter cell
growing more vigorously than the rest, soon occupies the
middle point of the cellular body, and is covered by the
other four cells which in the mean time have divided by
septa perpendicular to the outer surface (PI. XLIII, fig. 3).
The central cell afterwards divides into a lower, flat, tabular
cell, and an upper, spherical one. The lower tabular cell
soon divides by repeated bi-partition into four (PL XLIII,
fig. 5), then into eight, and afterwards into twelve cells. In
the lower part of the prothallium thus formed, the cells
which surround the sides of the larger central cell ultimately

21

322 HOFMEISTER, ON

divide by septa parallel to the outer surface (PI. XLIII,
tigs. 7 — 9). The four cells which project beyond the apex
of the larger cell expand above in a papillate manner
(PI. XLIII, fig. 5), after which each of them divides by a
transverse septum (PL XLIII, fig. 4). All the cells of the
prothallium, with the exception of these papillate cells and
the large central one, form chlorophyll granules in their
interior.

The increase in the circumference of the pro-embryo causes
a bending back of the surrounding pointed shreds of the inner
layer of the outer spore-membrane. The pro-embryo be-
comes visible in the form of an emerald-green wart at the
apex of the germinating spore. The four papillate cells at
the apex of the pro-embryo, and their four basal cells, now
part asimder at the commissure, and thus an open canal,
leading to the large central cell of the pro-embryo, is pro-
duced (PL XLIII, figs. 8, 9). Some of the papillate cells
sometimes divide now by a second transverse septum
(PL XLIII, fig. 9). A daughter-cell is in the mean time
formed within the large central cell, the contents of which
latter cell are finely granular and mucilaginous. This
daughter-cell soon after its formation almost entirely fills
the mother-cell (PL XLIII, figs. 8, 9). The central cell of
the prothallium, and the four projecting cells, constitute the
archegoniiun. The prothallium of Pilularia never produces
more than one archegoniiun.

The development and structure of the prothallium of
P. minuta entirely resemble those of P. globulifera as far
as my observations extend, with the single exception that
the base of the prothallium in the former is somewhat more
strongly constricted than in the latter, so that the prothal-
lium appears more spherical.

The small spores swell slightly after becoming free. The
outer spore-membrane splits at the apex, forming three
fissures, the direction of which corresponds to the edges of
contact of the spore with the three sister-spores produced
in the same mother-cell. The inner spore-membrane
bursts, and some small spherical cells escape from the
inner cavity of the spore ; these cells contain small starch -
grains and a lenticular vesicle attached to the wall (PL

THE HIGHER CRYPTOGAMIA. 323

XLIII, fig. 6). The lenticular vesicle encloses a very thin
spermatozoon rolled up in three or four coils, which soon
exhibits a rotatory motion in the interior of the enveloping
cell. By rupture of the cell-wall it ultimately becomes
free (PL XLIII, fig. G';), and moves about in the water
with helicoid contortions. Its fore-end, which is hardly
thicker than the other, carries a few oscillating cilia (PI.
XLIII, fig. 6, c—f). I have observed the actual entrance
of the motile spermatozoa into the mouth of the archego-
nium (PL XLIII, fig. 7).

A short time after the appearance of the spermatozoa in
the neighbourhood of the large germinating spore, the large
cell produced in the central cell of the prothallium appears
divided into a few cells. The arrangement of these cells
shows that their formation results from repeated division
of the mother-cell by means of septa at right angles to a
plane passing through the longitudinal axis of the archego-
nium (PI. XLIII, figs. 10, 11). The cells of the prothal-
lium, with the exception of the four papillate cells, multiply
in the mean time actively in all three directions of space,
especially the cells of the lower portion. Repeated divi-
sion also occurs in the cells of the few-celled body enclosed
in the prothallium, which body is the rudiment of the
new plant, or embryo ; and the result is, that the latter
soon becomes a body composed of very small cubical cells,
and having the form shown in PI. XLIII, figs. 12, 13.

That end of the embryo which is turned away from the
cavity of the large spore, and which points obliquely up-
wards, soon exhibits a more active development than is
seen in its other parts. It is transformed into a cone which
becomes continually more pointed as its development pro-
gresses. The multiplication of the cells is caused by con-
tinual division of the apical cell by differently inclined septa,
and by the division of the cells of the second degree thus
produced, by radial septa, and then by septa parallel to the
longitudinal axis of the cone. The mode of cell-multiplica-
tion resembles in its essential features that of the first frond
of the Polypodiacese (PL XLIII, fig. 15). A similar cell-
multiplication, which at first, however, is very slow, takes
place immediately underneath the place of origin of the

324 HOEMEISTER, ON

cone just mentioned (the first frond). Near it, at the oppo-
site end of the embryo, a similar but shorter mass of cel-
lular tissue soon begins to protrude (PL XLIII, fig. 15).
This is the first root, an adventitious root, differing in no
respect from those which afterwards appear in numbers. It
grows, like the adventitious roots of the Polypodiaceae and
Equisetacese, by division of a cell in the interior of the
tissue nearly underneath the apex of the organ. This divi-
sion is produced partly by septa almost parallel to the
basal surface, which is turned towards the apex of the root,
and partly by septa parallel to the lateral surfaces which
converge at an obtuse angle. The cells of the second
degree which lie towards the apex of the root have the
form of a meniscus ; their first division takes place by a
vertical septum bisecting the cell, after which a septum is
formed cutting the one last formed at right angles. The
four cells thus formed divide several times by longitudinal
septa, but not by transverse septa (PL XLIV, fig. 2C).
The part Of the root underneath the punctum vegetationis
grows much slower than the part above it. Close above
the punctum vegetationis the four outer cellular layers of
the root separate from the two axile ones, and an annular
air-cavity is produced. A similar air-cavity is formed in
the first frond, even in its early youth (PL XLIV, fig. 1).
The cells of the prothallium enclose the embryo on all sides
even during the development of the first frond and the first
root; they are much extended in the direction of the
length of this organ, and gradually compressed and ab-
sorbed even up to the outermost layer. Contemporane-
ously with the first appearance of the root, the part of the
embryo wrhich is turned towards the large cavity of the
spore, and. separated from the latter by a simple cellular
layer, becomes strongly concave (Plate XLIV, fig. I).
During the further development of the embryo it becomes
more and more arched, until at last it has assumed the form
of a short conical cellular mass enclosing an elongated pear-
shaped cavity in connexion with the interior of the spore
(PL XLIV, fig. 2). The cellular layer of the prothallium
which encloses this cavity is afterwards dissolved. The
distended portions of the proembryo which enclose the

THE HIGHER CRYPTOGAMIA. 325

first frond and the first root as it were with a sheath, are
ultimately unable to keep pace with the growth of the
latter. These portions are ruptured, and the apices of the
frond and of the root become free. Almost at the same
time the second frond appears near the place of origin of
the first frond, and separated from it by the blunt end of
the future principal axis : it has the form of a conical wart
(PI. XLIV, fig. 2), which by continual multiplication of the
cells of its apex grows rapidly in length.

As the plant becomes further developed the joints of the
stem elongate considerably : the terminal bud remains
rather sharply conical. From the underside of the stem,
in the immediate neighbourhood of the terminal bud,
numerous bicellular hairs enclosing the latter are pro-
duced, and further backwards, close underneath the place
of origin of each frond, adventitious roots make their
appearance. The basal cell of the hairs which are situ-
ated on the outer wall of the fruit, divides repeatedly, at
a late period and after the complete formation of the
apical cell, by transverse septa ; in this respect these hairs
bring to mind the scales of the Polypodiacese.

The large oval ripe spore of Marsilea pubescens, at the
time when it is discharged from the ruptured capsule, is of
a similar nature to that of PiMaria globulifera. The
inner cavity of the spore is clothed with a very delicate
membrane, which becomes somewhat more manifest by
distension, upon the application of caustic potash. In
contact with this membrane there is found at first a tole-
rably thick glassy layer of a yellowish colour. Except
at the apex of the spore — the spot, that is to say, which
answers to the place of contact of the spore with its
three sister -spores produced by the same cell — this
glassy membrane is surrounded by an outer membrane,
the component parts of which are prism-shaped, and
arranged in a radial manner. Out of this outer membrane,
and upon the apex of the spore, a portion of the middle
membrane protrudes in the form of a blunt wart. The
spore is enclosed in a thick layer of clear transparent homo-
geneous firm jelly, which extends beyond the apex of the
spore almost throughout its entire length. An enlarged

326 HOFMEISTER, ON

passage leads through this gelatinous mass to the pro-
truding portion of the inner spore-membrane. At the base
of this passage are found the debris of the three sister-
cells, which were produced in the same mother-cell with the
spore. These are small shrivelled tetrahedral cells, which
are attached by one of their points to the wart-like protru-
sion of the inner layer of the outer membrane of the spore
(Pl.XLIV,fig. 16)."

The inner cavity of the spore is filled with a fluid con-
sisting of albuminous matter and yellow oil, and containing
numerous large and small starch granules. The larger
granules exhibit manifest lamination, and sometimes also
indications of twin-granules. The protruding portion of the
apex of the spore is separated from the rest of the cavity of
the spore by a very delicate septum. It forms a distinct
cell filled with a finely granular mucilage. When treated
with caustic potash it exhibits in its middle point a nucleus
of an ellipsoid shape (PL XLIV, fig. 18). This cell is the
mother-cell of the prothallium.

Germination begins a feAV hours after the escape of the
spore from the opening fruit. In the primary cell of the
prothallium two new nuclei appear in the place of the pri-
mary nucleus which disappears (PI. XLIV, fig. 17), and
shortly afterwards the cell is divided into two longitudinal
halves by a vertical septum. The longitudinal division is
repeated in each half by a septum at right angles to the
former one (PL XLIV, fig. 19). In the mean time an
orange-red colouring matter appears in the mucilaginous
fluid contents of the two or the four cells, in the form of
small vesicles (or drops ?) By a series of bipartitions the
prothallium is transformed into a hemispherical cellular
mass (PL XLIV, figs. 20 — 24), consisting of a central cell
with mucilaginous contents, supported upon a double layer
surrounded by a triple layer of narrow cells. The four
longitudinal rows of cells which extend beyond the apex of
the central cell, part asunder at their edges of contact, and
an open narrow passage leading to that cell is formed (PL
XLIV, fig. 22).

The structure of the prothallium of Marsilea consequently
agrees in its essential features with that of Pilularia, except

THE HIGHER CRYPTOGAMIA. 327

that it is more massive, and differs from Pimlaria in the
subordinate point that the cells which form the mouth of
the passage leading to the central cell do not become papil-
late. Here, as there, the entire prothallium is devoted to
the formation of one archegonium.

The spores of Marsilea which came under my observation
did not become further developed. The small spores pro-
cured contemporaneously from the same fruit/'5 Avhich was
8^ years old, exhibited no change : it would seem that these
latter lose their power of germination sooner than the large
spores. The prothallia died when they had attained the
stage of development necessary for impregnation, inasmuch
as the small spores mingled in the surrounding fluid de-
veloped no spermatozoa. I observed the same phenomenon
in Pilularia minuta.

* For which I was indebted to the kindness of Alexander Braun. They
were part of the same gathering which yielded the materials for his and Mette-
nius's observations, and were found at Montpelier in 1S42.

CHAPTER XL

SALVINIA NATANS.

At the latter end of autumn the large ripe spores of
Salvinia form ellipsoidal cells whose longitudinal diameter
is from \'" to f, clothed with a thick outer membrane in
which two layers are visible, the inner one being horny, and
the outer one granular and of a looser texture. At the apex
of the spore — that pole of it which is tinned away from the
stalk of the sporangium — the outer membrane exhibits a
division into three lobes, the boundaries of which answer to
the edges of contact of the young spore with the three sister-
cells which were produced contemporaneously in the same
mother-cell.

The contents of the spore look like a quantity of oil and
albumen. Spherical drops, both large and small, of a half
fluid substance, swimming in a thinner fluid, fill the inte-
rior of the spore. The apical portion of it is occupied by a
larger accumulation of the like mucilage. The history of
the development of the spore, which when half ripe appears
filled with delicate round vesicles, as well as the behaviour
of the above spherical masses dming germination, render it
not improbable that some at least of those large drops arc
cellular formations filled with nutritive matter destined for
the germ-plant.

During the winter the walls of the fruit perish. The
sporangia — as well those which contain one large spore each,
as those which contain small spores — fall from their stalks,

HOEMEISTER, ON THE HIGHER CRYPTOGAMIA. 329

and are carried up to the surface of the water in the early
spring by the surrounding growing masses of confervas. In
the last weeks of March a short three-edged cellular body
of a beautiful emerald-green colour is seen at the apex of
the spore, between the three separated lobes of the outer
spore-membrane. This body is the prothallium.

The prothallium is produced by continued bi-partition of
the agglomeration of granular mucilage which was spread
over the arched apex of the interior of the spore, and has
become transformed into a flattened cell (PI. XLV, fig. 1).
The prothallium whilst still very young is already multicel-
lular, and exhibits a simple cellular layer, spread over the
inner arcuate cavity of the macrospore (PI. XLV, fig. 3).
When seen from above it appears to have a bluntly trian-
gular form (PI. XLV, fig. 4). From the arrangement of
the cells it may be concluded, that when the primary mother-
cell was first divided by septa perpendicular to the mem-
brane of the macrospore, a three-sided and a four-sided
moiety were normally formed upon each division. As soon
as the middle of the prothallium, by transverse division of
its cells, has attained a thickness of three cellular layers, the
first archegonium is formed at its apex. The position of the
cells of the prothallium — which at this time is still entirely
enclosed by the lobes of the spore-membrane and is devoid
of chlorophyll — when seen in longitudinal section, shows
clearly that this first archegonium was formed by transverse
division occurring twice in the middle cell of the prothallium.
The middle of the three daughter-cells becomes the central
cell of the archegonium. At first it is much drawn out in
width and is almost tabular (PI. XLV, fig. 5). The upper
cell first divides twice by longitudinal septa arranged cross-
wise. The four daughter-cells are afterwards, and after
their free outer surface has become arched, divided by trans-
verse septa (PL XLV, fig. 6). By parting asunder at their
edges of contact they form the canal leading to the central
cell. In the lower one of the three cells which are derived
from the middle cell of the prothallium, the cell-multiplica-
tion which prevails in the entire mass of the prothallium is
continued, and by this means the circumference of the latter
is considerably enlarged, and thus — some time after the

330 HOFMEISTEll, ON

formation of the first archegonium — the three lobes of the
outer spore-membrane* are bent back.

The formation of the subsequent archegonia, which appear
in numbers upon the prothallium, takes place in a similar
manner by transverse division of one of the cells of the outer
surface of the prothallium. The central cell is formed from
the inner of the daughter-cells, whilst from the outer ones
are produced the boundary cells of the canal leading to the
central cell. After the formation of those archegonia, which
are situated near the highest of the three blunt angles of
the three-sided, cushion-shaped prothallium, transverse divi-
sion is sometimes several times repeated in the covering-
cells of the archegonia, and in the tissue surrounding them.
The canal leading to the central cell of these latter arche-
gonia is of considerable length, and has a bent course (PI.
XLV, fig. 10).

At the commencement of the formation of the archego-
nium the central cell is quite filled with granular mucilage,
and a nucleus with more transparent contents floats in the
middle of it (PI. XLV, fig. 5). Afterwards, as the central
cell increases in size, the granular protoplasm accumulates
so as to cover the wall, and the nucleus is imbedded in it.
One or two oval or pear-shaped cells, in contact with the
inner Avail, are now visible in the upper arch of the cell :
these are the germinal vesicles (PI. XLV, figs. G — 9). They
not unfrequently occur in pairs, a fact not hitherto observed
in any other vascular cryptogam.

During these changes in the large spores, the sporangia
which contain small spores are also carried up to the surface
of the water, either in groups or singly. In autumn, when
the mother-plant dies, the small spores contained in each
ripe sporangium are firmly attached to one another and not
capable of isolation, their outlines being hardly distinguish-
able. This has been observed by Mettenius,f and the same
is the case even in early spring. If however such a spo-
rangium be subjected at this time to gentle pressure under

* The two glassy iuner layers remain during this process, as during the
entire act of germination, quite unchanged (PL XLV, fig. 2). The notion of
their conversion into an apparently cellular mass is erroneous. (Mettenius
'.Beitr. z. K. d. Rhizocarpeen/ p. 17.)

t 'Beitr. zur K. der Rhizocarpese.5 Frankfort, a. M., 1846, p. 19.

THE HIGHER CRYPTOGAMIA. 331

the microscope, spherical or elongated ellipsoidal cells may
be seen to escape from the fissures between the cells of the
wall as they part asunder. These spherical or ellipsoidal
cells are divided by delicate septa into from two to six com-
partments, filled with finely granular mucilage, in which
one or several nuclei float. Afterwards each compartment
contains from one to four free roundish cellules. Each of
these cellules encloses a spiral thread, a spermatozoon, which
after its escape by the rupture of the wall of the cellule
moves about actively in the water. Many of these cellules
— those namely which are less developed — contain, instead
of the spiral thread, a transparent vesicle (or nucleus?) in
the centre, in the interior of which dark spherical lumps of
mucilage (nucleoli ?) are sometimes visible. By careful
dissection of microsporangia under the microscope at the
beginning of March, I succeeded in separating entire the
inner cell membranes of the microspores from the glutinous
contents of the microsporangia, which consisted of the de-
tached and agglomerated exosporia of the microspores.
When isolated they appeared in the shape of cellules already
extended to an oval form, having a major axis of 17*5
m.m.m., with turbid granular contents, and a spherical trans-
parent nucleus (PL XLIV, fig. 26). In the latter half of
March the contents of the microsporangia are pultaceous :
the cellules lie free in the granular mucilage of the interior,
Avhicli is brownish green under transmitted lis;lit. Bv this
time the contents of the cellules are transparent, and most
of them are divided transversely (PI. XL1Y, fig. 5). Further
divisions lead to the formation of a multicellular oval body,
the antheridium, in the compartments of which the sperma-
tozoa are formed in the interior of spherical vesicles (PI.
XLIV, figs. 27 — 30). By using higher powers of the
microscope, it may be seen that the cilia of the spermatozoa,
which are less numerous than in the Polypodia cese, are of
unusual length (PI. XLIV, figs. 31, 32). The movements
of the spermatozoa are exactly like those of the spermatozoa
of the PolypodiaceEe, so far as regards the direction and the
rapidity of the motion.

I have several times in different years found spermatozoa
of this kind swimming about in the water in which Salvinia

332 HOFMEISTER, ON

had germinated. There can be no doubt that in the regular
course of nature, they are set free from the microsporangia
by gradual decay of the walls of the latter.

In archegonia which die without being impregnated and
become brown, the remains of the germinal vesicle are still
visible, and of their original size. Those archegonia how-
ever which by the widening of the central cell and the
multiplication of the cells adjoining to the latter give
evidence of impregnation, exhibit a considerable increase in
size of the germinal vesicle, which now almost fills the
central cell (PI. XLV, fig, 9).* As soon as it quite fills
the central cell, the first division of the impregnated ger-
minal vesicle takes place, by means of a transverse septum
slightly inclined to the longitudinal axis of the archegonium.
Cross longitudinal septa are produced in each of the two
halves, and then again slightly inclined transverse septa
are formed. The succession of these divisions is not
subject to any definite rule (PI. XLV, figs. 11 — 14):
the final result however is always the same, viz. the forma-
tion of an oval cellular body having its longitudinal axis at
right angles to that of the archegonium, and having one of
its apices, the blunter one, composed of four cells placed
crosswise (PI. XLV, fig. 14c), whilst the other apex only
exhibits a single top cell (PI. XLV, figs. 13, 14*, 15c). I
will call the latter the fore-end, and the former the hinder
end of the embryo.

At the hinder end the number of the cells increases
almost uniformly in all directions (PI. XLV, figs, 19, 21, 23).
At the fore-end on the other hand a particularly active cell-
multiplication occurs, which commences in the growing cell
adjoining the original apical cell of the pointed end of the
embryo. This cell-multiplication is produced by septa
inclined alternately forwards and backwards, and at right
angles to a plane passing through the longitudinal axis of
the archegonium and of the oval embryo. In this way an
excrescence originates which is directed upwards (PI. XLV,

* I did not succeed in observing spermatozoa in the interior of these arche-
gonia. A phenomenon which has been observed in different mosses and in
Pteris aquilina occurs, as an irregularity, also in Salvinia, viz., that the interior
of the archegonium enlarges more rapidly than the imperfectly developing
embryo, which is thus surrounded by a wider cavity (PI. XLV, fig. 12).

THE HIGHER CRYPTOGAMIA. 333

figs. 21 — 23,) and which becomes rapidly wider by longitu-
dinal divisions,* first of the apical cell, and then of the
other cells of the fore-edge (PI. XLV, figs. 20, 24,) of the
flat and leaf-like structure. This excrescence is the first
leaf.

Soon after its appearance, a shoot of the fore-end of the
embryo is observable underneath its place of attachment
and before its median line. This shoot appears at first as
a hemispherical, slighty protuberant, cellular excrescence.
The arrangement of the cells of the embryo, especially if
observed in a longitudinal section through the median line
of the first leaf (PI. XLV, fig. 21), leads to the conclusion
that the excrescence was formed by the division of the
apical cell of the fore-end, first by a septum inclined towards
the first leaf, and then by a septum inclined in the opposite
direction.! These divisions are repeated in regular suc-
cession in the terminal cell for the time being, which cell
has the form of a segment of a sphere. This excrescence
is the principal axis of the germ plant. On the right and
left of it the margin of the lamina of the first leaf is deve-
loped into ear shaped appendages (PI. XLV, figs. 24, 25"-c)-
AVhilst these — extending beyond the end of the principal
mass — approximate more and more nearly to one another,
the still leafless apex of the leafy shoot ramifies twice,
sending out the more slender ramification (normally) first
to the right and then to the left} (PI. XLV, fig. 25"-<:).
In the mean time the cells of the hinder end of the embryo
only multiply to a small extent. That end is now attached
at right angles in the form of a stalk-like prolonga-
tion, to the flat, proportionably thick, first leaf, which forms
the principal mass of the embryo (PL XLV, figs. 22, 2(5,
2b"'b'c). Its cells are now throughout almost cubical.

This growtli of the first leaf ruptures the prothalliuin
(PI. XLV, fig. 26). By the expansion of the cells of the
hinder end of the pro-embryo, — which expansion takes

* These divisions are interpolated between the divisions produced by septa
inclined to the outer surfaces.

f The succession of the division may be inverted (PI. XLV, fig. 19).

X The observer is supposed to look frum above upon the fore-surface of the
first leaf.

334 HOFMEISTEB, ON

place suddenly and at right angles * to the surface of the
first leaf — the first leaf arid the principal bud are carried
upwards out of the fissure (PL XLV, fig. 27). The stalk-
like organ which hears the first scutiform leaf is therefore
not formed exclusively, or even mainly, by the longitudinal
extension of either the lower end of the embryo which lies
opposite to the entrance to the archegonium, or of the
primary axis, which in Salvinia is only very slightly deve-
loped. The hinder end of the embryo plays the principal
part in the formation of the above-mentioned stalk.

The vascular bundles originate from the stalk. Never-
theless, the interior of the latter does not produce any
spiral vessels which pass immediately into the first leaf and
the stem above it (PI. XL\r, fig. 28) ; here all the cells of
the bundle remain thin-walled. The second and the third
leaf are formed behind the ramifications of the principal
bud, without the occurrence of any new ramifications
(PL XLV, fig. 28, 29). Then, however, the less vigorous
branches become elongated (usually ramifying again at the
same time), and form the leafless branches, of limited
growth, which hang down into the water, and which have
been generally considered by the earlier writers as adven-
titious roots, f These brandies grow by the repeated divi-
sion of an apical cell by means of septa, inclined alter-
nately in two directions, and by the division of the cells of
the second degree by a radial longitudinal septum, and
then by a transverse septum perpendicular to the axis.
Afterwards the cells divide, by septa parallel to the axis,
into inner and outer cells, and this latter division is several
times repeated in the cells of the circumference.

I observed myself — what Savi had previously noticed —
that microspores which had been carefully kept apart from
microsporangia developed a prothallium, but no embryos.
It is but rarely that two embryos are produced in the same
prothallium. I have only observed the occurrence twice.

The Rhizocarpeee have always attracted a considerable

* This direction forms an angle of about 30° with the longitudinal axis of
the embryo.

f Mettenius has correctly described them, 'Beitr. zur Botanik.,' Heft i,
(Heidelberg, 1850) p, 15.

THE HIGHER CRYPTOGAMIA. 335

amount of attention from botanists, especially their ger-
mination.* The knowledge of them had progressed
considerably when Schleiden's well-known work threw the
whole subject into confusion. f Schleiden alleged that the
small spores (pollen- grains, as he called them) emit a tube,
which penetrates into the prothallium developed from the
large spores, and is there transformed into the embryo.
Schleiden made these statements with a positiveness which
would have admitted of no contradiction, had it not been
for some almost unaccountable errors of observation.
Mettenius, in his beautiful and accurate work, ' Beitrage
zur Kenntniss der Rhizocarpeae,' did not venture to attack
this theory of Schleiden, although he was unable to verify
any one of Schleiden's observations. Nageli j never saw
the small spores of Pilularia emit tubes, but he made the
important discovery that the mother-cellules of the Sperma-
tozoa originate in them. He pointed out anew that the
four papillate cells of the mouth of the archegonium —
which Schleiden, strange to say, described as "pollen
grains seated upon the nucleus, and which had developed
tubes " — could not be pollen-grains, but that they rather
originated from the prothallium. I published the outlines
of the account given above many years ago.§ Mettenius,
in a subsequent work, adopted my views. ||

* The earlier literature is fully treated of in Mettenius's work ' Beitrage
zur Kemitncss der lihizocarpeen/ Frankfurt a. M., 1846, p. 1.
f ' Grundziige/ 2nd edition, p. 101.

% ' Zeitschri'ft f. Botanik.,' Heft 3 and 1, (Zurich, 1816,) p. 188.
f 'Bot. Zeit.,' 1819, No. 15.
i| ' Beitr. zur Botanik./ 1 Heft, Heidelberg, 1850.

CHAPTER XII.

ISOETES LACUSTRIS.

The development of the Isoetese is a subject of great
importance in botanical morphology. They are the only
known family in which the principal axis never ramifies.
As far as present observations extend, they alone, in the
vegetable kingdom, are distinguished by the entire sup-
pression of a supplementary cell-multiplication in the joints
of the stem. In other stems, however little their inter-
nodes may be developed, an active multiplication of the
cells in a longitudinal direction takes place (after the for-
mation of the youngest internode) in the second youngest,
or even in the adjoining internodes. In Isoetes, after the
formation of one internode, the longitudinal growth ter-
minates absolutely. The features by which the Isoetese
are clearly distinguishable from the plants nearest allied to
them in their mode of reproduction are as follows : — the
development of adventitious roots (apparently in a descend-
ing series), the form of the ligneous mass, and especially
the existence of a mantle of cambium surrounding the
wood and retaining its activity during the whole life of the
plant. The processes of impregnation are seen in Isoetes
with greater facility and clearness than in any other dise-
cious cryptogams.

Hugo von Mohl pointed out the peculiar phenomena of
growth of the Isoetese,* viz., the development of the adven-
titious roots in an apparently descending order on both
sides of a furrow traversino- the under surface of the

* 'Liunsea/ 1840. ' Vermischte Sclmften,' p. 122.

HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 337

flattened stem — the peculiar form of the wood — and the
annual renewal of the bark by the vitality of a cambium
layer surrounding the wood. Since Von Mohl's disco-
veries the special attention of botanists has been almost
constantly directed to this interesting family. Alexander
Braun * pointed out the connexion between the \ or §
arrangement of the fronds of young plants, and the two or
three-lobed form of the stem; he discovered the true
nature of the regular bifurcation of the roots, which had
been taken by earlier observers t for accidental lateral
ramification. He endeavoured to explain the remarkable
relation of the roots to the stem by the assumption that
" the roots in Isoetes, instead of breaking forth outwardly
from the vascular cylinder, penetrate, on the contrary, in
an inward direction." Mettenius,| about the same time,
gave a very accurate account of the structure of the ripe
spore, and suggested that the germination of Isoetes might
agree with that of Selaginella, as to which, § at the same
time, he published the first correct microscopical obser-
vations. A year afterwards, Karl Muller gave an account
of the germination of Isoetes lacustris. || He describes the
large spore (of which he had only advanced specimens
before him) as a cellular sac, enclosed by an exosporium,
and in whose cavity the rudiment of the embryo appeared
in the form of a free cell, which was gradually transformed
into the cellular body. Mettenius forthwith corrected the
most essential errors of this account.^" He proved anew,
in a striking manner,** the similarity of the germination of
Isoetes and the other vascular cryptogams, by the discovery
of the formation of spermatozoa in the small spores, and
the description of the origin of the archegonia upon the
prothallium developed by the large spores.

The following observations will afford some facts
supplementary to those noticed by Mettenius and Muller,

* 'Flora,' 1847, p. 32.

f Bischoff, 'Krypt. Gewaclise,' Niirnberg, 1828, p. 10.

% 'Linnsea,' 1847, p. 269, on Azolla.

§ 1. c, p. 270, note.

|| 'Bot. Zeit.,' 1848.

% 'Bot. Zeit.,' ] 848,' p. 688.

** 'Beitrage zur Botanik.,' Heft 1, Heidelberg, 1850.

22

338 HOFMEISTER, ON

and will be found in accordance with those reported by
Mold. I am indebted to the kindness of Mettenius,*
Alexander Braim, and Gustav Reichenbach,f for the abun-
dant materials upon which my observations are founded.

The large spores of Isoetes lacustris are at first tetra-
hedral with a convex basal surface. As they ripen, their
remaining surfaces also become gradually arched, and
assume almost a spherical form. The delicate primary cell-
membrane is clothed with a thick exosporium, which,
when cut through, exhibits three principal layers. The
innermost is a glassy membrane, of a brown colour and
moderate thickness, upon which ridges of different lengths,
and converging towards the pole of the spore, are seated.
Three of the longer and more prominent of such ridges,
answering to the edges of contact of the spore with its
three sister-spores, unite at the apex at angles of 120°.
They reach to the equator of the cell, and there intersect a
somewhat less prominent annular ridge, which surrounds
the spore. This innermost layer of the exosporium is
succeeded by a thinner layer, of a granular consistence
and yellowish colour, over which the thick outermost
covering, consisting of a transparent gelatinous mass, is
spread. Like the former one, it covers all the ridge-like
protuberances of the innermost glassy layer of the exos-
porium, and it is especially fully developed over the four
principal ridges (PL XLVI, fig. 1).

The matter composing the exosporium behaves towards
reagents like the exine of pollen-grains. Sulphuric acid
imparts a reddish colour to the inner layers, which are soft-
ened by boiling in alkaline leys. The gelatinous layer is
rapidly destroyed by mineral acids and caustic alkalis. As
Roper i has observed, the exosporium does not contain
carbonate of lime, although Schleiden§> suspected its pre-
sence from the appearance of the dry spores. The contents
of the ripe spore in its optical and chemical characters

* I received living specimens of Isoetes lacustris from the lake in the Black
Forest, the same habitat which afforded the materials for the observations of
Bischoff, Mohl, Braun, and Mettcnius.

-j" Dried specimens of species of the Mediterranean Flora.

% ' Zur Flora Mecklenburg's,' vol. i, p. 125.

\ ' Grundziige,' 2nd edit., vol, ii, p. 84.

THE HIGHER CRYPTOGAMIA. 339

resemble a mixture of oil and albumen. If a spore be
crushed upon thin paper, it leaves behind a transparent stain.

A few weeks after the spore has become free by the decay
of the walls of the sporangia, its interior begins to be filled
with cellular tissue. Sections afford no explanation as to
the nature of this cell-formation. If a spore which is not
yet entirely filled with closed parenchyma be crushed, its
contents become a formless pultaceous mass. If however
the exosporium be immersed for half an hour in a saturated
solution of glycerine, it becomes sufficiently transparent to
expose to view flatly-spherical accumulations of a granular
substance spread over the inner wall of the spore (PI. XL VI,
fig. 1). There can be no doubt that these masses of granu-
lar mucilage, which become confluent when the spore is
submitted to pressure, are newly-formed primordial cells,
i. e., naked primordial utricles ; and therefore that the for-
mation of the cellular tissue which fills the spore, i. e., of
the prothallium, is the result of free cell-formation. This
accords with the mode of origin of the endosperm of the
greater number of phsenogams, and especially with the de-
velopment of the albumen of the Coniferre. The formation
of rigid cell-membranes appears to commence for the first
time when the accumulated contents of the spore-cell have
become transformed into daughter-cells.

This cell-formation probably commences in the apical
arch of the spore-cavity. When the parenchyma of the
spore is sufficiently firm to admit of longitudinal sections,
the cells of the apex of the prothallium are far smaller and
more numerous than those of its base. This leads to the
conclusion that a multiplication of the cells has commenced
at the apex some time previously, which multiplication does
not take place at the base until a much later period, and
then with far less activity. The contents of the cells of the
prothallium are not distinguishable from those of the ripe
spore. No nuclei are visible in the thick turbid fluid.*

During the formation of the prothallium the inner mem-

* The want of transparency of the milky cell-contents is so great, that even
in very thin sections it prevents the recognition of the boundaries of the cells
as long as the preparation lies in clean water. The addition of concentrated
solution of glycerine produces with greater rapidity a far more perfect trans-
parency than the chloride of calcium recommended by Mettenius, (' Beitr. zui*
Bot.,' Heft i, p. 11.)

340 HOFMEISTER, ON

brane of the spore changes considerably, especially in its
upper portion. It increases in thickness, and when a section
is made, several layers are distinguishable. It can with
difficulty be stripped off from the prothallium.* When
viewed superficially the membrane which was previously
homogeneous appears finely granular — all which phenomena
are found to occur in a remarkably similar manner in the
embryo-sac of the Coniferse.

The spherical prothallium increases in size by multiplica-
tion and expansion of its cells, and ruptures the upper half
of the exosporium, dividing it into three lobes, each of the
three ridges which unite at the apex of the spore separating
into two longitudinal halves. A small portion of the apex
of the prothallium — three very pointed triangles meeting at
angles of 120° — is thus made free.

Archegonia are produced by the multiplication of indivi-
dual cells of the upper surface of these exposed portions.
The first of these archegonia is produced exactly at the apex
of the prothallium (PI. XLVI, fig. 2). If this first one
remains unimpregnated several others are formed in descend-
ing order. I have never counted more than eight.

The mother-cell of an archegonium divides by a septum
parallel to the free outer surface, and a similar division
takes place in the outer of the two newly-formed cells.
Vertical longitudinal septa then divide each of the two
upper cells into longitudinal moieties (PI. XLVI, fig. 'da),
in each of which a longitudinal septum at right angles to
the one last formed is immediately produced. The under-
most cell of the archegonium increases somewhat in size
and becomes the central cell. Division by transverse septa
usually occurs once more in the lower of the two double
pairs of (four times smaller) cells which project beyond the
central cell (PI. XLVI, fig. 3, a1). Exceptions to this are rare.

During these processes the part of the inner membrane
of the spore-cell which is not covered by the exosporium
peels off gradually, swelling up in front.t By the parting
asunder of the four longitudinal rows of cells which cover

* Compare Mettenius, 'Bot. Zeit.,' 1848, p. G90.

f The mode of growth of the adventitious roots of some grasses, especially
of Aveua sativa, affords a very remarkable instance of the peeling off of whole
masses of cellular tissue by the casting off of the primary membrane and the
thickening layers of the epidermal cells.

THE HIGHER CRYPTOGAMIA. 341

the central cell of the archegonium, an open passage is
formed leading to the latter cell (PI. XLVI, fig. 5). Before
the formation of this passage a tree spherical daughter-cell
is produced in the central cell, almost filling the cavity of
the latter (PI. XLVI, figs. 4—6). It is the primary cell of
the new generation — the germinal vesicle — capable, after
impregnation by the spermatozoa produced in the small
spores, of forming a new frond and spore-bearing plant of
Isoetes.

All the ripe macrospores of Isoetes lacastris form pro-
thallia and produce archegonia. The further development
which results in the formation of the embryos of a leaf-
bearing plant is attained only by those macrospores which
come in communication with microspores. This is analo-
gous to what occurs in Selaginella and the Rhizoearpeae.
Prothallia when kept quite apart from microspores live for
a long time ; according to my experiments from the begin-
ning of September to the middle of March. Some of these
even then brought forth new archegonia of the normal form
apparently fitted for impregnation.

The small spores of Isoetes lacastris when ripe have the
form of the quadrant of a sphere ; in rare instances they are
tetrahedral. The sharp edges and angles of the spore are
formed of exine, those of the inner spore-membrane are
bluntly rounded off. At both the upper and lower ends of
the spore the exosporium forms a wart-like tip (PI. XLV,
figs. 8, 9) ; all along the edges of contact of the spore with
the three sister-spores it forms a prominent fold (PI. XLVI,
fig. 7). The outer surface of the exine is very finely granu-
lated, almost smooth. Its colour is a light yellowish grey.

The fully-developed small spore contains a finely granu-
lar protoplasm mixed with many small oil-drops. When
viewed with transmitted light the mass of differently refrac-
tive fluids appears almost opaque. A sharp-outlined sphe-
rical nucleus with transparent fluid contents floats in the
middle point of the spore (PI. XLVI, fig. 7).

A bout four weeks after the microspores have become free
by the decay of the wall of the sporangia, the primordial utricle
of the cell divides into from two to four portions which be-
come individualised into daughter-cells (PL XLVI, fig. 8).

312 HOFMEISTER, ON

Sometimes the moieties of the primordial utricle fill the
mother-cell entirely ; the cell-walls secreted by them then
appear — so far as they correspond with the surfaces of
contact of two halves of the primordial utricle — like septa
seated upon the inner wall of the spore (PL XLVI, fig. 9).*
More frequently however the division of the cell-contents is
accompanied by a contraction! of them into a smaller space ;
the daughter-cells, which are of a flatly ellipsoidal form, lie
free in the interior of the spore. Numerous very small
amyloid granules now appear in the fluid contents of the
daughter-cells. Each of these cellules produces in its inte-
rior one or two lenticular vesicles, in each of which is pro-
duced a thread, rolled up in a right-handed spiral, and
consisting of a substance rendered brown by iodine (PL
XLVI, fig. 11). One of its ends is somewhat thickened,
the other is drawn out into a thread-like termination.
When perfect, the spore and its daughter- cells are ruptured
by the swelling of the contents ; the lenticular mother-
vesicles of the spermatozoa become free in the opened cavity
of the spore. Soon the membrane of the vesicle itself —
which is rendered blue by iodine — is ruptured ; one end of
the spermatozoon protrudes from the fissure, and immediately
commences an active oscillatory motion, which causes a rapid
revolution of the mother-vesicle (PL XLVI, fig. 12). Ulti-
mately the spermatozoon frees itself entirely from the vesicle,
and the turns of the spiral separate somewhat from one
another. It slips out of the ruptured spore, maintaining a
constant revolution round the axis of its spiral, and moves
about in the water with the thick end in front, dragging the
thinner one after it (PL XLVI, figs. 13 — 15). Its motions
are slightly more rapid than those of the spermatozoa of
mosses 4

If the spermatazoon be killed with iodine, a small number

* Spores thus divided are exactly like the small ellipsoidal cellular bodies
which burst forth in the spring from those sporangia of Sahiaia nutans which
produce microspores, i. e., the cellules in whose chambers the mother-vesicles
of the spermatozoa originate.

f Analogous to the process occurring in the spore-formation of liverworts
and mosses (Pellia and Phascum).

% Mettenius, who discovered the spermatozoa of Isoetes, remarks upon the
slowness of their motion compared with the rapid motion of the spermatozoa of
ferns.

THE HIGHER CRYPTOGAMIA. 343

of very fine cilia attached to the two front coils of the spiral
may be distinguished under favorable illumination (PI.
XLVI, figs. 16, 17). The addition of colouring matter to
the water in which the spermatozoa are moving, shows that
during the life of the latter these cilia oscillate actively.
The duration of the motion of the spermatozoa of Isoetes
never exceeds three hours according to my observations.

Microspores sown at the end of August produced the
first spermatozoa in the middle of September. The pro-
duction of spermatozoa lasted until January. The water
of the vessels in which I sowed the large and small spores,
swarmed with spermatozoa on some days in the middle
of October. At this time the thinly-fluid mucilage which
fills the canal of the mouth of ripe archegonia, often con-
tained thread-like bodies of a firm mucilaginous substance,
which might be the remains of spermatozoa, whose motion
had ceased.

The first indication of the commencement of the develop-
ment of an embryo in an archegonium, is the division of
the impregnated germinal vesicle by a transverse septum,
somewhat inclined to the longitudinal axis of the archego-
mum (PI. XLVI, figs 18, 20). During the formation of
this septum the germinal vesicle expands, often to some
extent, in a direction at right angles to the longitudinal
axis of the archegonium. After the disappearance of the
primary nucleus of the cell and the appearance of two new
nuclei, the lower of the two halves of the impregnated
germinal vesicle, and afterAvards the upper half also, is
divided by a septum cutting the first formed septum at a
right angle (PI. XLVI, fig. 21). The rudiment of the embryo
of the new generation, when consisting of from two to four
cells, has the form of a procumbent oval ; when viewed in the
direction of its longitudinal axis (Plate XLVI, figs. 18, 19),
it appears not longer than the unimpregnated germinal
vesicle. But owing to its longitudinal expansion, it has
already began to penetrate destructively into the tissue of
the prothallium.

As in many similar cases, the cells of the prothallium
which immediately adjoin the rudimentary embryo, exhibit
a somewhat active multiplication before they become

344 HOFMEISTER, ON

loosened and pushed aside by the developing germ-plant,
and ultimately dissolved.* The embryo in its first stages
appears surrounded by a tissue of very narrow cells (PL
XL VI, fig. 21). As early as during the occurrence of
the first divisions of the impregnated germinal vesicle, the
cells of the mouth of its archegonium die ; their fluid con-
tents become as clear as water, and their walls assume the
deep-brown colour so common in the dead cell-membranes
of vascular cryptogams. Similar changes sometimes occur
in those cells of the upper surface of the prothallium which
adjoin the mouth of the archegonium (PL XLVI, figs. 21,
23).

It very rarely happens that more than one archegonium
of the same prothallium is impregnated. The rest wither ;
the contents of their central cells shrivel up into an irregu-
larly shaped ball of dark-brown matter, and all the cell-
membranes of the archegonium become brown.

The rudiment of the embryo when 4-celled grows to-
wards the middle point of the spherical prothallium by
repeated division of the cells turned away from the canal of
the archegonium. At the same time an active multiplica-
tion commences in the one lateral cell which occupies the
more pointed end of the oval embryo-rudiment. It jdivicles
by a vertical septum forming an acute angle with one of
the axes of the embryo. The outer of the newly-formed
cells is immediately divided again by a septum at right
angles to the last-formed septum. In the apical cell for
the time being of the excrescence (of the embryo) thus
produced, the division is repeated for a long time by septa
inclined alternately in two different directions (PL XLVI,
figs. 22, 23). This lateral shoot of the young rudimentary
plant — which shoot up to a certain point is continually
elongating — is the first leaf.

The cells of the second degree produced by the division
of the (primary) apical cell of the leaf, are divided by radial
longitudinal septa. Each of the tertiary cells divides —

* Instances of this occur in the development, whilst within the prothallium,
of the germ-plant of ferns— in the penetration of the lower end of the moss-
fruit into the incipient vaginula— and in the displacement of the endosperm of
many phamogams by the growing embryo.

THE HIGHER CRYPTOGAMIA. 345

by septa parallel to the chords of the arched free outer
surfaces — into an inner and an outer cell. In the latter a
septum is produced at right angles to the one immediately
preceding it, and radial to the longitudinal axis of the leaf;
close under the growing tip of the leaf eight peripheral
cells enclose four axile ones. The form of the leaf, which
at first is flattened above and below, is gradually changed
by this cell-multiplication into a conical one (PI. XLVI,
fig. 24). The leaf increases in thickness by repeated divi-
sion of the cells of its circumference, produced by radial
longitudinal septa alternating with septa parallel to the
tangents of the free outer walls. When it has attained a
certain stage of development its longitudinal growth is
much accelerated by the occurrence of transverse division
in most of its cells. This multiplication commences close
underneath the apex of the leaf, and progresses from
thence, on the one side towards the base, and on the other
side towards the apex, so far at least as it extends into those
cells of the apex of the leaf which have been formed since
its commencement. The cells of the circumference divide
first ; from the latter the multiplication proceeds towards
the longitudinal axis, without reaching the four rows of
cells adjoining the latter. The latter remain twice as long
as the cells of the peripheral layer ; they are destined at a
later period, by repeated longitudinal divisions, to become
transformed into vascular bundles (PL XLVII, fig. 1).

The first leaf either shoots out at right angles from ]
the longitudinal axis of the archegonium and embryo, or
it trends upwards, often at such an acute angle that its-'
apex penetrates into the upper arch of the central cell of
the archegonium. The latter case is the most frequent ; it
very rarely happens on the other hand that the leaf takes a
downward direction towards the centre of the prothal-
lium.

As early as the time when the number of the cells of the
leaf, counted in a longitudinal direction, amounts to from four
to six only, the free outer wrall of the cell which occupies
the middle of the base of the upper surface of the leaf — that
surface which is turned towards the apex of the proth al-
lium— begins to swell in a vesicular manner (PI. XLVI,

346 HOFMEISTER, ON

fig. 23). The protuberance has the form of an ellipsoid flat-
tened on the upper and under side, and is separated from
the original cavity of the mother-cell by a septum (PI.
XL VI, fig. 24). The roundish cell, not unlike a knobby
hair, which is now seated at the base of the fore side of the
leaf, is the primary cell of the single scale which it produces.
Its first divisions exactly resemble those of the cell of the
first degree of one of the gemmae of Marchantia or Lunu-
laria. The cell is divided two or three times by transverse
septa, which are at right angles to the future longitudinal
axis of the scale, and perpendicular to its surfaces (PI.
XLVII, fig. 1). The apical cell then divides, and after it
the lower cells also, by a longitudinal septum at right angles
to the one previously formed. The halves increase — after
new transverse septa have been formed in each of the two
upper cells — by the growth of septa parallel to the free
outer edges of the scale, followed by septa produced in the
outer of the newly formed cells at right angles to the outer
margin. The organ which has now the shape of a blunt
spatula (PI. XLIX, fig. 4), continues to increase the number
of its cells by the division of those of its circumference by
means of longitudinal and transverse septa which alternate
with tolerable regularity. This activity of the cells terminates
much sooner at the apex of the leaf than at its base, where
an intercalary multiplication of the cells occurs, mainly in
a longitudinal direction, some time after the cells of the apex
of the leaf have lost their power of division. The scale be-
comes pointed and heart-shaped (PL XLIX, fig. 5).

All these septa are perpendicular to the surfaces of the
scale. Soon, however, septa parallel to its surfaces appear
in its middle cells (PI. XLVII, fig. 2). Thence the divi-
sion advances towards the cells of the base of the leaf,
which are engaged in intercalary multiplication in length
and breadth. In the cells nearest to the base the divi-
sion is sometimes repeated, so that this part of the scale
consists of three layers. The remainder of it has two
layers, with the exception of the margin and the top,
which always exhibit a single layer of cells. Individual
cells of the margin grow out into rather long pointed
papilla?.

THE HIGHER CRYPTOGAMIA. 347

In all the principal features the development of the scale
of Isoetes accords with that of the scales of ferns. The
first commencement of the multiplication of the single
primary cell is essentially the same in both, i. e., it rests
upon the alternation of rectangular, longitudinal, and
transverse divisions ; besides this, both exhibit the subse-
quent intercalary basal cell-multiplication, and the same
kind of multiplication of the median cellular layers ; and
lastly, in both cases the development of the scales rapidly
gets ahead of that of the organ to which they form appen-
dages, and they soon die.

Immediately after the commencement of the formation
of the scale, a sheath begins to be formed at the base of the
leaf, enclosing the scale and some of the cells underneath
it. A horse-shoe-shaped, cushion-like protuberance, open
towards the front surface of the leaf, is first formed by the
arching outwards of the free outer wall of a girdle of cells
surrounding those parts (PI. XLVII, fig. 24). When the
intercalary cell-multiplication of the base of the leaf takes
place, this protuberance grows up into a tolerably high
annular sheath, by repeated division of the apical cell for
the time being by means of horizontal septa (PI. XLVII,

The leaf grows in thickness at the point of origin of the
scale ; its fore-side appears bent obliquely inwards (PI.
XLVII, figs. 2, 3), close above the base (PL XLVII, figs.
2, 3). In its lower part, the vascular bundle which tra-
verses it is excentrical, being nearer to the front surface.

The primary axis of the germ-plant, which at the time of
the appearance of the first leaf consisted of only a few
cells, increases considerably in length and circumference
during the development of the leaf and the formation of
its scale. This increase is caused more by expansion than
by multiplication of its cells. The axis nowr projects
considerably from the embryo, in a hemispherical form,
and is directed towards the middle point of the pro-
thallium ; the leaf is seated upon one of the lateral sur-
faces of the embryo (Pl.XLVI,fig. 24; PI. XLVII,figs.l-3).

A process of cell-multiplication has now commenced
upon its opposite lateral surface also : this is the beginning

348 HOFMEISTER, ON

of the formation of the first root, an adventitious one, like
all the roots of the vascular cryptogams. Its development
commences with the multiplication of a cell of the inner
tissue of the embryo, viz., the cell which lies opposite to
the primary cell of the first leaf, and is separated by a
cellular layer from the upper surface of the germ-plant
(PI. XLVII, fig. 1). This cell divides, in repeated succes-
sion, by transverse septa opposite to one another, forming
cells of the second degree, lying alternately above and
below the primary cell. The lower ones are produced by
the formation of a septum slightly convex below ; their
form is that of a meniscus. Their multiplication takes
place in two directions only ; all the septa which are
formed in them are perpendicular to the arched upper and
under surface of the cell whose derivative cells constitute
one of the cap-shaped cellular layers — enclosed one within
the other — which cover the outermost apex of the root, and
which, during the growth of the latter, gradually peel off
outwardly (PI. XLVII, fig. 3). After the formation of a
lower secondary cell, and before the division of the cell of
the first degree by a septum opposite to the last-formed
septum, septa parallel to the longitudinal axis of the root
are produced in the latter cell three times in succession.
One of these septa is turned towards the outer side of the
root — that side which is turned away from the punctum
vegetationis of the germ-plant. The two other septa are
at right angles to this one. Thus three lateral cells of the
second degree are formed, which are followed by the pro-
duction of a shorter upper cell by the division of the
primary cell by means of a transverse septum (PL XLVII,
fig. 3). I will call the first three the outer, the second the
inner of the upper secondary cells. Both kinds of upper
cells of the second degree, the lateral cells as well as those
which follow them, multiply in all three directions. Their
divisions are oftener repeated and last longer than those of
the lower secondary cell which belongs to the same period
of division of the primary cell.

The formation of lateral cells of the second deoree
causes a very considerable unilateral thickening of the root.
The diameter of the latter increases much more rapidly on

THE HIGHER CRYPTOGAMIA. 349

that side which is turned away from the future place of
origin of the second root, than on the opposite side. The
consequence of this is that each new cap-shaped covering
layer of the tip of the root appears to be attached more
obliquely than the preceding one, and reaches higher up on
that side of the root which is turned towards the punctum
vegetationis than it does on the opposite side.

Each newly-formed inner cell of the upper cells of the
second degree is first divided into unequal longitudinal por-
tions by a septum inclined inwards to the axis of the root,
the inner portion, that, namely, which is turned towards the
punctum vegetationis of the germ-plant, being the smaller
one. Both portions multiply immediately in all three direc-
tions. The two innermost cells which adjoin the longitu-
dinal axis of the root, and are turned towards one another,
remain about one step behind all the others in the process
of division by transverse septa, i. e., by septa at right
angles to the longitudinal axis of the root. Instead of
that division they each divide twice by longitudinal septa
at right angles to one another. Thus there is produced
within the root a string of sixteen longitudinal rows of
extended cells, situated excentrically, being nearer to the
inner side. This is the rudiment of the vascular bundle
(PI. XLVII, fig. 3). The cells of the outer surface of that
portion of the root, which,- — as opposed to the root-cap
which peels off little by little — may be called the persistent
portion, divide by radial longitudinal septa and by trans-
verse septa once oftener than those of the inner surface ;
the epidermis of the root consists of tabular cells four
times smaller than those adjoining them on the inside.
These divisions of the cells of the outer surface occur even
within the region which is protected by the transient cap-
shaped covering layers of the tip of the root ; they occur
on the outer side of the root, where these coverings do not
extend so high up, earlier (/. e., nearer to the tip of 'the
root) than on the inner side (PI. XLVII, fig. 3).

Some of these circumstances attract but little attention
in the first root of the germ plant which is hardly as thick
as a bristle, in consequence of the inferior development of
the tissue destined to form the bark of the root. In order

350 HOFMEISTER, ON

to explain them I must speak, in anticipation, of the process
of development of vigorous roots of plants some years old
(PI. LII, figs. 2—5).

The one cell which is situated underneath the place of
insertion of the scale of the first frond, and is surrounded
by its sheath- like base, is the punctum vegetationis of the
(secondary) principal axis of the plant ; the terminal bud
of the embryo is at this time limited to this one cell. As
the bud is developed the cell divides by septa inclined
alternately in opposite directions. The lines in which these
septa cut one another are at right angles to the front surface
of the first leaf.

Until the plant is fully formed the growth of the stem is
caused by the constantly repeated uniform division of the
apical cell. The direction of the septa produced in it re-
mains always the same, viz., at right angles to the major
axis of the ellipsoidal transverse section of the stem, and
parallel to the furrows of its under side.

The mode of multiplication of the cells of the second de-
gree which are thus produced, resembles in general that of
the same cells of the first leaf above described. After the for-
mation of the second secondary cell, the second leaf is pro-
duced on that side of the end of the principal axis which is
turned away from the first leaf, by the multiplication of the
youngest cell of the second degree of the stem-bud. The
mode of its development corresponds entirely with that of
the first (PI. XLVII, figs. 2, 3). Its formation commences
immediately after the first root becomes visible ; during its
development the upward growth of the surrounding sheath
of the first leaf ceases for some time. When the second
leaf has attained a height of from three to four cells, a re-
markable elongation of the cells of the first leaf — which now
contain chlorophyll — commences at the apex of the latter.
In consequence of the multiplication of its cells in a longi-
tudinal direction, the first leaf has by this time advanced
almost to the periphery of the prothallium. The leaf breaks
through the prothallium and appears in the form of a green
point outside the latter : it elongates itself very rapidly by
the longitudinal expansion of its cells, which proceeds from
the apex of the leaf towards its base, where cell-multiplica-

THE HIGHER CRYPTOGAMIA. 351

tion is still in progress. In my experiments the first
leaves broke ont from the ends of the prothallia at the end
of September, six weeks after the spores were sown. From
that time leaves continued to make their appearance singly
until the middle of January, when their number suddenly
diminished in a remarkable maimer. From the beginning
of February until towards the end of March no new germ-
plants became visible; at the commencement of spring-
however they began to appear again, becoming continually
more numerous until the middle of April. Even in the
middle of May almost all the prothallia which I examined
contained embryos in different stages of development. These
prothallia were surrounded by the episporium, and had
been produced from a sowing made in the middle of the
preceding: August. Such was the result of chamber culture.
It is probable that in the natural condition the embryos
which break through the prothalliuin in winter do not
survive, and that those germ-plants only which are produced
in spring attain to a further development.

Soon after the appearance of the first leaf, the first root
also breaks through the prothallium. It bends itself down-
wards and penetrates into the mud, the leaf having a vertical
direction, inasmuch as being specifically the lighter portion
of the plant it stands erect in the water. The prothallium
is now attached laterally to the embryo. The thin mass of
cellular tissue at its apex forms a ring round that portion
of the germ-plant between the root and the front surface of
the leaf. The large-celled blunt end of the primary axis of
the young plant extends into the principal portion of the
prothallium, whose cell- contents, like those of the cells of
the first axis of the plant, henceforth become gradually
transformed into a transparent fluid.

After the breaking through of the leaf and the root, the
further development of the germ-plant ceases for about a
month. Expansion and multiplication of the cells of the
first leaf and of the first root still continue, taking place in
the former by intercalary multiplication of the cells of the
base of the leaf, in the latter by the growth of the apex.
But the formation of new leaves and new roots goes on only
slowly and gradually.

352 HOFMEISTER, ON

The above-mentioned two-fold longitudinal division of the
string of elongated cells which become differentiated in the
interior of the leaf and root does not occur until after the lat-
ter have emerged from the prothallium. The divisions appear
to take place contemporaneously throughout the entire
length of both the cellular strings which unite underneath
the terminal bud. The division by transverse septa of the
basal cells of the leaf, continues even after the commence-
ment of the formation of the vascular bundle, although in
a less degree ; and the cells of the string which goes to
form the vascular bundles take part from time to time in
the division. One single longitudinal row of cells is en-
tirely exempt from it. This row originates in the middle
of the fore side of the vascular bundle, by supplementary
longitudinal division of a row of cambial cells. In the
cells of this row, whose length — owing to the entire sup-
pression of all transverse division — far exceeds that of all
the neighbouring cells, thickened annular threads soon
make their appearance, passing here and there into spiral
threads (PL XLVII, fig. 3). The continual longitudinal
growth of the surrounding tissue stretches and distorts the
young vessel, and removes the annular threads to a consi-
derable distance from one another.

In like manner there appears on the inner side of the
rudimentary vascular bundle of the root a row of elongated
spiral and annular cells of a prosenchymatal form like the
vessels of the leaf. In the first node of the plants, at the
place where the precursors* of the vascular bundles of the
leaf and root unite underneath the rudiment of the second
leaf, more than one of the longitudinal rows of cambial
cells assume a prosenchymatal form, and thickenings of the
walls are formed in all of them (PI. XLVIII, fig. 1).
These cells, which are the first rudiments of the wood, are
short and spindle-shaped, t and already bear some resem-
blance in form to the cells of which the principal mass of
the wood of the mature plant will consist.

Many of the cells of the tissue which adjoins the vascular

* Precurseurs ILirhel.

■f The intercalary transverse division has not extended to the cells adjoining
these.

THE HIGHER CRYPTOGAMIA. 353

bundles of the leaf and of the root separate at their edges,
and the intercellular cavities become filled with air. The
tissue which is filled with air soon dries up ; at last it
disappears altogether, and large air-cavities are formed ; —
four cylindrical cavities parallel to the axis are formed in
the leaf, and are divided into a series of compartments by
persistent cellular surfaces ; in the root one large air-cavity
is formed in front of, and near to the excentrical vas-
cular bundle.

Whilst the base of the second leaf begins to form a
sheath round the terminal bud, the latter produces the
third leaf at a point opposite to the second, and above the
first (PI. XLVTI, fig. 3). At the same time the forma-
tion of the second root commences. It originates under
the second leaf, opposite to the first root, very near to the
first node, and is produced by the multiplication of a cell
adjoining the string of cells which goes to form the vascular
bundle. It is formed in precisely the same manner as the
first root, with which it makes an angle of about 30° open-
ing downwards. A plane passing through the longitudinal
axis of the first and second leaves and of the first root,
usually bisects the second root also ; small lateral deviations
are however not uncommon. The root in its longitudinal
development stretches the outermost cellular layer of the
rudimentary stem of the germ-plant to a considerable ex-
tent before it breaks through it (PI. XLVII, fig. 3).

The rudiment of the third root, like that of the first and
second, only becomes visible when the third leaf has
already attained a certain degree of longitudinal develop-
ment. It is produced, like the second, by the multiplica-
tion of a cell adjacent to the lower end of the precursor of
the vascular bundle, and to the rudimentary ligneous body
of the germ-plant, and originates consequently on the left
hand, close above the place of origin of the first root, In
its development it turns itself at once somewhat side-
ways ; it makes its way through the cortical tissue of the
stem of the germ-plant in a direction which diverges about
30° laterally from that of the first root.

The fourth and the following leaves, at least as far as the

23

351 HOtfMEISTER, ON

eighth, exhibit the \ arrangement.* The commence-
ment of the formation of each new leaf takes place some
time before the cessation of the growth (i. e., the cell-mul-
tiplication of the base) of the next preceding one. The
lowest part of the back of the leaves enters into the forma-
tion of the bark of the stem, like the base of the underside
of the leaf of the Equiseta, the Lycopodiacese, and the phae-
nogams. The I arrangement of the leaves causes an
excessive increase in the mass of the cortical tissue at two
points of the circumference of the stem lying opposite to
one another, and corresponding with the dorsal surfaces of
the leaves. Here the bark is developed so as to form two
fleshy bodies widened at the base,f and spreading obliquely
downwards from the ligneous body of the stem. These
bodies are separated from one another by a flat indentation
which is at right angles to the large horizontal axis
of the stem, and is the first rudiment of the characteristic
furrow of the underside of the stem.

The development of each young leaf, and the growth in
thickness of its base, proceed pari passu with the cell-multi-
plication in circumference and diameter, of the older
portion of the end of the stem, as well as of the base of the
preceding leaf by which the young leaf is sheathed. The
active increase in the number of the cells round the upper
end of the longitudinal axis, pushes the previously formed
portions of the circumference of the stem continually
further outwards. The latter are able to bear this pressure
for a long time by the expansion of their cells in a tangen-
tial direction. But in the plane which passes through the
small horizontal axis of the stem this expansion is almost
entirely suppressed. At this part the cortical parenchyma
splits from the outside (sideways and from below), at an
early period, by which means the furrow of the under side
of the stem is made much deeper.

Shortly after the commencement of the formation of each
new leaf, a new root is produced laterally beneath it ; the

* As Alex. Braun remarked in 1847 ('Flora,' p. 135), and which he pointed
out as the immediate cause of the bipartite arrangement of the stem of Isoetes.
f This widening is due to the greater vigour of each new leaf.

THE HIGHER CRYPTOGAMIA. 355

fourth being near to the second, and obliquely opposite to the
third. The primary cell of the fifth root lies near the first,
exactly opposite to the third. The sixth originates near the
second obliquely opposite to the fifth. The places of origin of
the roots of the first year — as well as of all the successive
periods of vegetation — consequently all lie in a plane
passing through the indentation of the underside and the
terminal bud of the stem. The roots are developed in
ascending order. Each new root originates somewhat
higher up, and farther from the longitudinal axis of the
stem than the second preceding one, i. e., its next neigh-
bour underneath. The points of origin of the roots of the
first vegetative period form together an arc slightly convex
below (PI. XLIX, figs. 1, lh). During the development
and the penetration through the bark of the roots sub-
sequent to the third root, the former are compelled (like
the third root itself), to bend downwards towards the
furrow* of the stem, in order to avoid the vascular bundles
of the preceding roots. If the third root diverges to the
right of the longitudinal axis of the elliptical transverse
section of the stem, then the fourth will turn to the left of
it, the fifth also to the left, the sixth to the right, and so
forth. Each new root converges at a more acute angle
to the small horizontal axis of the stem ; the last roots of
the first year are almost parallel to that axis and to the
furrow of the underside of the stem (PI. XLVIII, fig. 5).

The roots as they break through the bark bend sharply
downwards, and appear on the underside of the stem
arranged in two rows almost parallel to the indentation of
the latter. The locus of the points of penetration of the
roots may be considered as forming an elongated ellipse. f
The roots which are nearest to the centre of the stem and
the lowest down, are the oldest, those which spring from
the wide lateral margins and are the highest up, are the
youngest. The vascular bundles of the third and following
roots, which are excentrical like those of the first and
second, are brought near to that side of the root which is
turned towards the furrow of the stem ; the excentricity

* This furrow becomes continually more and more clearly defined.
f Von Mohl, ' Vermischte Schriften,' p. 137.

356 HOFMEISTER, ON

is reckoned not with reference to the longitudinal axis of the
stem, but to a plane passing through this axis and the in-
dentation of the stein, in which plane the points of origin of
the roots are situated.

The tissue of the region of the stem in which the
closely crowded horizontal places of origin of the vascular
bundles of the leaves meet together, goes to form the
upward-growing portion of the proportionally slight woody
mass which occupies the longitudinal axis of the stem, but
encloses no pith.

In the germ-plant, as long as the J arrangement of
the leaves lasts, this upper half of the woody mass has a
two edged form. Its usually spindle-shaped cells — reti-
culated and spiral cells mixed with a few delicate walled
cells —have almost all the same direction ; they are parallel
to the larger transverse diameter of the woody mass (PI.
XLVI1I, figs. 2, 3 ; PL XLIX, fig. V). A longitudinal sec-
tion through the furrow of the stem cuts all the wood-cells
transversely. As the arrangement of the leaves passes
through the S into the §, |, T53, and £ arrangements, the
upper part of the woody mass becomes round, and the di-
rection and form of its cells very various, appearing at first
sight to have no regularity, owing more particularly to the
fact that now many other cells besides the primary cells of
the vascular bundles take part in the wood-formation.
Spiral cells are also formed which are situated between the
converging rudimentary portions of the vascular bundles ;
by this means the woody mass is closed up to the form of
a cylinder.

The closely crowded points of origin of the roots repre-
sent the under half of' the woody mass : a row of spiral
cells concave above, at right angles to the larger horizontal
axis of the upper mass of wood, which latter in the first
year is two-edged.

At the close of the first vegetative period of the germ-
plant the cells of the bark are filled with amyloid granules,
mixed with a few oil- drops. The cells, however, which
immediately surround the mass of wood retain their capa-
city for multiplication. Some time before the commence-
ment of the first period of winter-rest they have divided

THE HIGHER CRYPTOGAMIA. 357

once, twice, or three times by septa parallel to the longitu-
dinal axis of the wood. Thus there is formed a mantle of
cambium surrounding the mass of wood on the sides and
from beloAv, and passing above into the growing cellular
tissue of the end of the bud.

At the recommencement of vegetation in the second year
an active multiplication of the cells of this cambial layer
begins. The increase in size keeps pace with the growth
in thickness of the new portion of the stem produced by the
development of the terminal bud. The multiplication of
the cambial cells is most remarkable at the sides of the
mass of wood ; it is less vigorous in that half of the cam-
bium which surrounds the lower, half-moon-shaped portion
of the woody mass.

The development of the cambium has pushed outwards
the cortical tissue which is filled with assimilated matter.
The vascular bundles are thereby much stretched, but not
so as to destroy them. The vitality of the cells of the
vascular bundles manifestly still exists ; by the expansion
of their own walls they follow the change of position of the
surrounding tissue. The thickenings of the walls of the
vessels are alone materially changed during these processes,
being loosened here and there and in other places distorted,
so that every trace of regular arrangement disappears (PI.
LXI, fig. 3). The function also of the vascular bundle does
not seem to have come to an end at the time of the com-
mencement of the vegetative period which succeeds its
formation. The starch and oil contained in the cells of the
bark of the previous year — which bark has been pushed
outwards — are gradually sucked up and carried to the grow-
ing portions of the plant. At the end of each vegetative
year the cells of the bark of the preceding year contain only
a transparent fluid.

The old bark which is pushed outwards, gradually dies
from the periphery inwards ; its cell-walls assume a deep
brown colour, and ultimately the bark perishes. The new
bark behaves similarly to the old bark, in the fact that the
cells of the portion which clothes the furrow of the stem
only expand slightly in breadth. The indentation of the
stem already appears deeper than in the preceding year, on

358 HOFMEISTER, ON

account of the less active development of the corresponding
region of the bark-forming cambium, and it becomes deeper
still by the regular tearing away of the tissue of the bark
from the sides, that tissue not being stretched transversely.

The roots of the previous year are pushed for some dis-
tance outwards and downwards with the bark through
which they have penetrated. Like the latter they assume
a deep brown colour and die.

The new roots destined for the support of the plant
during the current period of vegetation originate on the
convex edge of the lower, half-moon-shaped portion of the
mass of wood, by the multiplication of some of the cambial
cells adjoining the wood. The nature of their cell-multipli-
cation corresponds in almost every respect with the account
given above of the first root. The only difference is that
during the passage through the bark the transient cellular
layers of the root-caps are inordinately developed, and the
permanent cortical layer of the root, on the other hand, very
slightly so.

The first root of the second year is formed close under
the place of origin of the first root of the germ-plant, at the
spot where the development of the cambium has torn off
the vascular bundle of the root about to be cast off — i. c, at
the place of attachment of the latter root. The second root
originates underneath the place of insertion of the second
root of the previous year, the third under that of the third
root of the previous year, and so forth. In their direction
also the new roots agree entirely with the older ones. The
two first originate opposite to one another, trending away
from the lateral surfaces of the lower growth of wood, and
bent in different directions inter se. They break forth op-
posite to one another in a perpendicular direction underneath
the terminal bud, on both sides of the furrow of the stem.
The third and following roots bend more and more side-
ways. The two last pairs of roots of one period of vegeta-
tion traverse the bark almost parallel to the furrow of the
stein. All the roots as they grow through the bark describe
a flattened are concave to the indentation of the stem. A
longitudinal section taken throush that indentation lavs
bare within each half of the stem only the rudiments and

THE HIGHER CRYPTOGAMIA. 359

the tip of the older of the roots which are still hidden
within the bark : the middle portion of the root is bent
away from the plane of the section (PI. LI, fig. 1).

As in the first year so also in the following ones the bark
is pierced by the new roots close under the deepest part of
the indentation. The brown roots of the previous year
stand far outside those of the current year. Inasmuch as
many of them last for two, three, or four years before they
become quite decayed, the result is that in some plants,
especially the older ones, the peculiarity observed by Von
Mohl makes its appearance with the greatest distinctness.
This peculiarity is, that the oldest roots are the outermost
and apparently the highest, the youngest the innermost and
apparently the lowest. As appears from what has been
said above, this is only an apparent irregularity, depending
upon the unusually vigorous development of the bark, and
its yearly renovation from within outwards.

It is a rule without exception that the middle ones of
each series of generations of roots are the oldest, that those
which are nearer to the lateral terminal points of the furrow
of the stem break forth at a later period than those in its
middle point. This circumstance however is not unfre-
quently less striking, owing to the fact that the duration of
each root is far less strictly limited to any definite period
than that of the leaves. The outermost roots of the pre-
ceding series are almost always in a state of vitality when
the first innermost ones of the next series begin to appear.
Old vigorous individuals which form a large number (as
many as twenty) of leaves in the course of one year, develope
during this period two complete series of generations of
roots » the whole cycle, commencing with the lowest inner-
most roots and progressing to the outermost, is formed
twice in succession (PI. LI, fig. 1). In the Isoetes from
South Europe and North Africa, which produce an abund-
ance of roots, as many as six generations of roots are pro-
duced in the same vegetative period. With the close of
each cycle of roots a double pair is added to the number of
the roots of the previous year, which double pair originates
at the horns of the half-moon-shaped lower portion of the
mass of wood (PI LI, fig. I)-

360 HOFME1STER, ON

The position of the vascular bundles of the roots remains
throughout the whole life of the plant the same as in the
first year : they are always brought close to that side of the
root which is turned towards the indentation of the stem.
The cambial cells between the places of origin of those
vascular bundles which pass to the new roots become for
the most part woody : individual cells only, situated between
the transformed annular and spiral cells, remain thin-walled
(PL LII, fig. 6). Thus the latterally compressed lower half
of the woody mass grows downwards at its convex edge, at
the same time increasing in diameter.

The roots of Isoetes usually ramify in a furcate manner
repeatedly — as many as four times — during their longitudi-
nal development.* Judging from the arrangement of the
cells of roots which have only just become forked, it would
seem that the furcation commences with the longitudinal
division of the cell of the first degree of the apex of the root,
by means of a septum at right angles to the larger trans-
verse diameter of the downward-growing wood (PI. LII, fig.
2). The forks of the roots separate from one another at an
angle of about 30°; the twTo first are parallel to the furrow
of the stem. The direction of the next ramifications differs
by about 90° from the former. The excentrical vascular
bundles of the forks of the root are always removed to that
side which is turned towards the sister-fork of the root
(PL LII, fig. 3).

Every year the same processes are repeated. The old
bark is thrown off and replaced by new. The upper cylin-
drical portion of the wood grows upwards by the lignification
of those cells of the terminal bud which overlie its summit,
and by the addition of the rudiments of vascular bundles
intended for the new roots. Its half-moon-shaped lower
portion increases in circumference on the convex edge, by
the addition of the bases of the vascular bundles which
jmss to the new roots. Thus the plant becomes continually
more vigorous ; the number of the leaves and roots increases
in each new vegetative period.

The abundant development of leaves, in connexion with

* Discovered by Alexander Braun in 1847. ' Flora,' p, 33.

THE HIGHER CRYPTOGAMIA. 361

the entire suppression of intercalary cell-multiplication in
the joints of the principal axis, leads necessarily to the result
that the younger portion of the bark formed out of the con-
fluent basal portions of the leaves projects far beyond the
punctum vegetationis of the principal axis. The top of old
plants exhibits a remarkable funnel-shaped depression, upon
whose inwardly-inclined slope the younger leaves which
sheath one another are seated (PL LI, fig. 1; PL LII, fig. 1).
The terminal bud occupies the base of the crateriform de-
pression, exhibiting a blunt cone of cellular tissue (PL L,
figs. 1, 2), surrounded at moderate distances by the rudi-
ments of the youngest leaves, which in plants of from five to
eight years old have the T53 arrangement.

The nature of the cell-multiplication of the terminal bud
remains (as has been said) the same throughout the entire
life of the plant. The alternately oblique septa by which
the apical cell divides in repeated succession, are inclined to
the large lobes of the bark ; a plane passing through the
furrow of the stem cuts those septa at right angles. The
daughter-cells of the cells of the second degree soon divide
by transverse septa, and become cells of the third or fourth
degree (PL LI, figs. 1, 2). Close under the apex of the termi-
nal bud the arrangement of the cells, which at first was
ladder-like, is changed into a concentrical scale-like arrange-
ment. The inner cells — those nearest to the axis of the
stem — of the derivatives of the third- and fourth-youngest
cell of the second degree, expand remarkably in width in a
direction radial to the longitudinal axis of the wood. By
this means the terminal bud, even above the place of origin
of the youngest leaf, is quite flattened (PL L, figs. 1,2).

The effect of the yearly renovation of the cambial layer is
not only to increase and renew the cortical tissue, but new
spiral cells also become added, although only sparingly, to
the wood of old vigorous plants. Individual cells of the
cambium, separated by two or three cambial cells from the
older principal mass of the wood, often exhibit thickenings
of the walls, which by their delicacy and want of colour
betray their undoubtedly recent origin (PL LI, fig. 2).
New elementary organs are never added to the oldest por-
tions of the wood, those namely which are formed in the one

36.2 HOFMEISTER, ON

and two-year old germ-plant : the two-edged lower end of its
upper part retains its form unchanged during the entire life of
the plant (PI. LI, fig. 1; PL LI I, fig. 1). the formation of
new wood around that already present seems only to last
during a few vegetative cycles. All longitudinal sections of
plants from three to eight years old exhibit a somewhat
exuberant enlarged growth of the wood close under the
upper end. This locus of the greatest thickness of the wood
consequently moves continually upwards during the develop-
ment of the plant.

The primary portions of the vascular bundles which
passed ofT into the leaves and roots formed many years pre-
viously, and which portions are attached to the wood, are
compressed by the cambium surrounding their sides, which
is always in a state of active vitality. Ultimately these
portions are torn off and pushed outwards, and the stump
which adjoins the mass of the wood is grown over by the
cambium just in the same manner as the stem of a tree gets
rid of the boughs of its lower portion.

The vigorous leaves of plants of many years' growth ex-
hibit in their earliest stages, when viewed in front, the
ladder-like arrangement of their cells (PI. LII, fig. 7) which
is the necessary result of the mode of multiplication of the
cell of the first degree. This however soon becomes indis-
tinct by the rapid and vigorous development of the leaf in
thickness. The form, when viewed from above, of leaves
which are somewhat more developed (PI. LI, fig. 5) leads to
the conclusion that now, after each two divisions by septa
at right angles to the fore and hind surfaces of the leaf, septa
are formed in the terminal cell at right angles to the lateral
surfaces of the leaf and turned towards its front or hind side.

Isoetes lacustris exhibits a manifest periodicity in the
interchange of sterile and fertile leaves.* In the terrestrial
species this interchange is very striking. Microscopical
investigation shows that the rudiments of the leaves are
formed a full year before they are developed; the fruit-
bearing ones being produced late in summer and in autumn,
and the sterile ones in spring and early summer. During

* Described by Alexander Braun iu the 'Flora,' 1847, p. 34. But see
Biscboff, 'Krypt. Gewachse,' p. 84.

THE HIGHER CRYPTOGAMIA. 363

the winter the development of the leaves is considerably
retarded, but does not entirely cease. Those leaves which
are first formed in winter and make their appearance at the
end of the next autumn, are very imperfect. In the scanty
development of the leafy portion, and the vigorous develop-
ment of the base, thev form the transition to the stipule-like
organ which in the terrestrial Isoetes, especially I. Durieui
and Hi/strid1, appear at the commencement and the close of
every vegetative period.* In the semi-terrestrial species
such as i~. velata and adspersa, the last leaves of the year
exhibit — in a more marked manner than I. lacustris — a dis-
torted leafy portion and an overgrown sheathing portion
whose cells are quite filled with starch and oil.

The scales of the first leaves only of the germ-plant origi-
nate immediately above the place of attachment of the leaf.
With the second leaf frequently, with the third and following-
ones always, the case is different. Here the cell which by
the vesicular protrusion of its outer wall lays the foundation
of the scale, is removed by at least one cell from the base
of the leaf (PL XLYII, fig. 3; PL XLIX, fig. I5). The
intercalary cell-multiplication of the base of the leaf takes
place with remarkable activity in this one cell and in those
cells which lie in the same horizontal plane. By this means
the scale is carried upwards to some height on the leaf (PL
L, figs. 1, 2 ; PL LIU, figs. 2, 3). A flat three-sided cellu-
lar mass then sprouts forth from the leaf close under the
scale and covering the base of the latter (PL L11I, figs. 2, 3).
Beyond and over the sides of this cellular mass the two
lower angles of the triangular scale are developed in a down-
ward direction ; the base of the scale becomes heart-shaped
like the scales of the Polypodiaceae (PL XLIX, fig. 5). The
cells of the base, which are inserted in the tissue of the leaf,
exhibit a vitality which forms a marked contrast to the early
cessation of the growth of its free portion. The horizontal
row of cells produced by the multiplication of the first cell
of the second degree belonging to the scale — which cell is en-
closed by the substance of the leaf — is transformed by a
series of rapidly repeated divisions into a transversely-ex-
tended ellipsoidal cellular body, the two ends of which, by

* Alex. Brann, in 'Exploration Scientifique de l'Algerie,' PI. 36, fig. 1*, 2b.

364 IIOFMEISTER, ON

repeated multiplication of the cells, ultimately grow upwards
in such a manner that the base of the scale becomes a fleshy
mass of very small cells with turbid contents, having the
form of a horse-shoe opening upwards, and inclined inwards
to the longitudinal axis of the leaf. Underneath also the
exuberant growth of the base of the scale extends into the
three-sided shoot of the front surface of the leaf, partly
pushing forward the existing cellular tissue (PI. LIII, fig. 5).
As the longitudinal development of the leaf draws to a close,
those of its cells which adjoin the highly-developed base of
the scale become ligneous by spiral thickenings of the walls.
Almost all the cells of the interior of the ligule-like shoot of
the fore-side of the leaf take part in this wood-formation*
(PI. XLIX, fig. 1). In an upward direction it is only the
one cellular layer adjoining the place of insertion of the
scale which is transformed into spiral cells ; on the other
hand the whole of the tissue enclosed by the two horns of
the half-moon-shaped base of the scale becomes woody.
The middle of the lower end of the woody mass which is
produced at a late period reaches close to the axile vascular
bundle of the leaf.

The leaves of Isoetes lacustris which are formed in the
third year after germination, and are developed in the
fourth year, produce the first fruit. The rudiment of the
sporangium f is formed in the earliest youth of the leaf, at
the time of the commencement of the intercalary multipli-
cation of its base. Of the two cells into which — by a
tranverse septum — the cell underneath the place of inser-
tion of the scale is divided, the upper one becomes the

* First observed by Mettenius, ' Linnsea,' 1847.

f Sclileiden, out of love for some supposed analogies with the lower crypto-
gams, will only apply the term " sporangia" to the spore-mother-cells of the
mosses and vascular cryptogams. Like most other botanists, I use the term
" sporangia " for the fruit containing the spore-mother-cells and spores, for
the capsules of mosses and liverworts, for the fruit of ferns and Lycopods, and
for those portions of the fructification of the Equisetaceas and Khizocarpeae
which immediately enclose the spores. 1 do so because the term " sporangium"
was first applied to the fruit of ferns. It appears neither necessary nor advisa-
ble to use the same term for the Fungi, Lichens, aud Algae, as is used for the
Characeee, mosses and vascular cryptogams. Moreover the expression " spo-
rangium" is quite unnecessary in the case of the lower cryptogams. De-
scriptive botany already possesses a more than sufficient number of suitable
names for the organs in question.

THE HIGHER CRYPTOGAMIA. 365

primary cell of the ligulate process which covers the base
of the scale, and the lower one becomes the primary
mother-cell of the sporangium (PI. LIII, fig. 1). By
repeated divisions in all three directions, especially in a
longitudinal direction, the latter is soon changed into
an oval hillock of cellular tissue, whose longitudinal axis
coincides with that of the leaf (PI. LIII, figs. 2, 3). The
longitudinal and transverse divisions produced by septa
perpendicular to the front surface of the leaf, are more
active in each of the new outer cellular layers of the rudi-
ment of the fruit, which are formed by septa parallel to
the free outer walls of the cells of the upper surface. The
young sporangium soon becomes an oval cellular mass at-
tached to the leaf by a proportionally small basal surface.
The tissue of the leaf which adjoins the place of attach-
ment of the sporangium afterwards — when spore-formation
begins — overgrows the fruit on all sides, principally above ;
it forms a membranous border, reaching far above the
sporangium, and is the veil of descriptive botanists (PI.
LIII, fig. 5).

Until shortly before the appearance of this last
growth of the base of the leaf, the sporangium con-
sists throughout of homogeneous delicate wailed cells,
which now besin to be differentiated into three different
sorts of tissue. The twro outermost cellular layers assume
more and more a tabular shape, and become the capsule
wall. The interior divides into groups of delicate-walled
cells in close connexion with one another — the primary
mother-cells of the spores — and into plates separating
these groups of cells from one another, and formed each of
two layers of cells whose intercellular cavities contain air.
The cells of the wall of the sporangium, as also those of
the tissue destined to produce the reproductive cells, con-
tinue to multiply by division for some time longer. The
cells of the plates which divide the portions of that tissue
from one another keep pace with the increase in size of the
sporangium by expansion of their wralls (PL LIII, fig. 4).

At last the spore-mother-cells separate from one another,
and assume a globular form (PI. LIII, figs. 6, 7, 8). In
the sporangia intended to form small spores, more generations

366 HOtfMiiiSTER, ON

of spore-mother-cells are produced than in those which
form macrospores ; the spore-moth er-cells of the latter are
considerably larger. The spore-mother- cells, both after
and before their individualization, exhibit a very distinct
large nucleus. By degrees the outline of the latter becomes
fainter ; at last the nucleus vanishes after two flatly-spherical
accumulations of granular matter have made their appear-
ance between its periphery and the inner wall of the cell (PI.
LIII, fig. 9). After the disappearance of the membrane of
the primary nucleus the above accumulations of mucilage
immediately assume an ellipsoidal shape, and appear as two
secondary nuclei (PL LIIT, fig. 11). Sometimes the spore-
mother-cell now divides by a transverse septum, after the
constriction of its contents at the equator (PI. LIII, figs.
10, 12), and each of the two halves — after the dissolution of
their ellipsoidal nucleus, and the appearance of two globular
daughter-nuclei — is divided into two daughter-cells having
the form of quadrants of a sphere (PL LIII, figs. 15 — 17).
Sometimes, however, the two secondary nuclei of the mother-
cell are dissolved before the commencement of the division
of the cell ; four tertiary spherical nuclei appear (PL LIII,
figs. 13, 14), and the cell divides at once into four daughter-
cells. This latter case is bv far the most uncommon one.
At their first appearance the four nuclei usually lie in one
plane, and the four daughter-cells of the mother- cell (the
special-mother-cells) retain, as in the first case, the form of
quadrants of a sphere. It is only very rarely that the
special-mother-cells are arranged in the angles of a tetra-
hedron. The septa by which the special-mother-cells are
separated are of a gelatinous nature. They swell up easily
and quickly in water. If their contents are made to contract
by the application of diluted acids, the cell walls swell up
into a mass simliar to that into which the contents contract.
The special- mother-cells of the small spores separate very
shortly after their formation. When separate they retain
their three-edged (rarely six-edged) form. Now, for the
first time — by analogy to the similar phenomenon in Equi-
setum — there is produced in each special-mother- cell a
daughter-cell, whose form exactly corresponds with that
of the special-mother-cell. The daughter-cell becomes

THE HIGHER CRIPTOGAMIA. 367

clothed with an episporium (PI. LIII, fig. 18), of the nature
described at the commencement of this chapter, and be-
comes free by the dissolution of the special-mother-cell,
some time before the rupture of the walls of the sporangium
permits the escape of the spores, whose outward ap-
pearance, when ripe, exhibits no farther change. The
special-mother-cells of the large spores, which have always a
tetrahedral arrangement, remain for a longer time united in
fours — even until after the formation of the exosporium.*

Alexander Braun's observations have shown that amongst
the species of Isoetes, those at least of the old world,
Isoetes lacustris is the only one which has only one furrow
on the underside of the stem. All others, the South-West
European and the North African species, have three, in
exceptional cases, four, deep indentations of the under
surface of the principal axis. The new roots break forth
from the base of the deep furrow ; in the species which
inhabit dry localities these roots are far more numerous than
in Isoetes lacustris. Even in the three-furrowed species
the form and structure of the wood always corresponds
exactly with the number and position of the furrows of the
bark. The lower portion of the wood is three-armed ; it
consists of three laterally-flattened arched masses of wood,
meeting at angles of 120°, and formed out of the closely
crowded rudiments of the vascular bundles of the roots,
and of the tissue between these vascular bundles, part of
which tissue is changed into spiral cells, and part remains
thin-walled. Where the number of roots is much greater
than in Isoetes lacustris, as is the case especially with
I. Hystrix and I, Durieui, the development of the lower
part of the wood also is unequal. Each of the three arms
of the lower half of the wood meets one of the deep cortical
furrows (PI. LIII, fig. 20). The newly formed roots originate
the lower arched margin of the plate of wood ; they bend
in an arcuate manner, and breaking through the side-walls
of the furrow, make their appearance at the deepest part
of the latter. Many cycles of roots are developed in each
vegative period j I have seen as many as eight in old strong
plants of Isoetes Ilystrino. In the greater number of the

* Wahlenberg, 'Flora Lapponica,' PI. xxvi, fig. 1, K.

368 HOFMEISTER, ON

roots of such plants it is manifest that the uppermost roots
of the individual rows are the youngest, a fact which is
not so easily seen in Isoetes lacustris. In the three-furrowed
Isoetes also the vascular bundles of the roots are excen-
trical ; they are pushed towards that side of the root which
is turned towards the cortical furrow in which the root
breaks forth. The yearly renewal of the bark by the de-
velopment of the mantle of cambium which also surrounds
the lower three-armed portion of the wood, causes the
removal of the older roots in a lateral direction away from
the indentation of the stem in which they first appeared,
and pushes them downwards and outwards. In the three-
furrowed species however this change of position is less
remarkable than in Isoetes lacustris.

In the three-furrowed species the stem occasionally ex-
hibits a fourfold division ; this appears to happen most
frequently in Isoetes tenuissima, I found it to occur in
two specimens out of seven. In stems of this sort the
lower portion of the woody mass is four-armed.

The terminal bud of most of the three-furrowed Isoetes
is far more deeply buried than even in Isoetes lacustris
(PL LI II, fig. 21). This partly arises from the propor-
tionally greater number of the leaves, and the consequently
more rapid increase of the cortical tissue. One essential
cause of the phenomenon is, however, the circumstance that
the cambium-layer — which clothes the cylindrical portion
of the woody mass, and which becoming prominent at
three places, as in Isoetes lacustris, reaches to the outermost
ends of the upwardly- curved arms of the lower portion of
the wood — has far greater vigour, on account of the much
more considerable radius of the lower portion of the woody
mass. The activity of the numerous layers of cambial
cells, which are almost convex above, must necessarilv in-
crease the mass of the bark more rapidly than is the case in
Isoetes lacustris.

The leaves of the three-furrowed species, the multiplica-
tion of whose cells usually agrees with that of Isoetes
lacustris, exhibit a far greater variety in their morphology
and anatomy. The stipule-formation mentioned in a previ-
ous part of this chapter is an example of this. The most

THE HIGHER CRYPTOGAMIA. 369

remarkable phenomenon, however, is that exhibited by
Isoetes IIi/strLv, and Durieui, in the lignification of the
masses of cellular tissue of the bases of their leaves,* which
varies in the different varieties of these species. The
cells remain in the closest connexion, and are thickened in
a porous manner by the superposition of dark-brown layers
upon the inner Avails, so that, as in Niphobolus chinensts, a
stony, closed bark is formed round the stem. By the
development of new leaves the lignified portions of the
bases of the leaves are pushed more and more outwards
and — after the death of the herbaceous parts of the leaves —
form a close spiny covering to the stem which can hardly
be cut with the sharpest knife, and is a sad hindrance in
the examination of these parts.

In the three-furrowed species of Isoetes, the end of the
stem, which occupies the base of the deep and steep depres-
sion of the top of the stem, is a wart of cellular tissue of
a much flatter form than in Isoetes lacustris. It grows
like that of I lacustris, by continually repeated division
of the single apical cell. The nature of the cell-multiplica-
tion is, however, essentially different. The septa, an end-
less series of which appear in the apical cell, are turned
in three different directions. The apical cell has the form
of a three-sided pyramid, with the top turned downwards ;
the cells of the second degree are produced by the forma-
tion of septa successively parallel to each one of the lateral
surfaces (PI. LIII, fig. 22). The cells of the second
degree form a spiral, winding round the middle point of
the primary cell, which spiral, as far as observations have
hitherto gone, is ahvays a right-handed one, and becomes a
snail-shell-spiral, in consecuience of the fact, that the cells
of the second degree from the time of their formation
grow by expansion and multiplication in all three direc-
tions.

As far as observations have hitherto gone, all the septa
formed in the apical cell and turned in one of the
three directions, are at right angles to a plane passing
through that indentation of the stem which is nearest
to them. Consequently, in one of the most essential

* A. Brauii, 1. c, pp. 35, 36.

24

370 HOFME1STEE, ON

features, the mode of growth of the terminal bud of the
three-furrowed species of Isoetes agrees with that of
Isoetes lacustris : the septa which appear in the apical cell
are turned towards the furrows of the stem.

Isoetes lacustris — as is well known*" — exhibits occa-
sionally, but rarely, a three-furrowed stem. Transverse sec-
tions of the stems of plants of this kindf exactly resemble
those of Isoetes setacea. The lower part of the woody mass
has three short arms (PL XLVIII, figs. 6, 7). The mode of
multiplication of the apical cell of the terminal bud is ex-
actly the same (PI. XLVIII, fig. 8).

Like the Selaginelke amongst the Lycopocls, Isoetes, in its
mode of reproduction, resembles — more indeed than any
other cryptogam — that group of phsenogams which comes
nearest to the cryptogams, viz., the Coniferae. The pro-
thallium, which consists of cells devoid of chlorophyll,
occupies a space not much greater than the macrospore
itself. It originates by free cell-formation in the interior
of the spore-cell. In both respects it comports itself in a
manner precisely similar to that of the albuminous body of
the Coniferae. The archeo'onia of Isoetes in the most
essential features of their development and structure ex-
actly resemble the corpuscula of the Coniferse.

Amongst the dioecious cryptogams — the cryptogams
with spores of two different sizes, of which the larger pro-
duce the germs of the second, spore-bearing generation,
and the smaller produce the spermatozoa by which the
germs are impregnated — Isoetes exhibits more clearly than
any other the necessity for the operation of both kinds
of spores in the process of reproduction. In Pilularia and
Marsilea the reproductive cells are surrounded by an
abundance of mucilage, which hinders the examination of
the spermatozoa, a state of things which occurs in many
of the lower plants and animals of the most different kinds.
In Salvinia observation is impeded by the firm adhesion
of the small spores, and by the difference in the time of
development of the microspores and macrospores when sown
contemporaneously. In Isoetes, on the other hand, the

* A. Braim, ' Flora,' 1847, p. 34.

f Amongst more than 100 specimens I found only one of this kind.

THE HIGHER CltYPTOGAMIA. 371

mode of appearance, and the abundance, of both kinds of
reproductive cells, are favorable to the observation of the
origin of spermatozoa in the smaller archegonial prothallia,
and not less so to the observation of the separate develop-
ment of the microspores and macrospores.

The germination of Isoetes, like that of the Ophioglosseee,
is distinguished from that of the vascular cryptogams which
have green prothallia in one essential point. In these the
lateral cell of the limited primary axis of the embryo, from
whose multiplication the (secondary) principal axis pro-
ceeds, lies in the apical region of the former. The leaf-
bearing principal axis developes the first leaf on the side
which is turned away from the apex of the primary axis and
towards the exit of the archegonium. The first leaf lies
above the principal bud, between it and the mouth of the
archegonium, as is the case with the Ferns and the Rhizo-
carpese. In Isoetes, on the other hand, the bud of un-
limited growth lies near the first adventitious root, close
under the canal of the archegonium, and the first leaf lies
under that bud. Judging from the position of the first
root on the germ-plant, Selaginella would exhibit a similar
state of affairs, were it not for the fact, that here the secondary
principal axis of the plant, instead of producing a leaf
close above its point of origin, divides into two branches,
having previously grown considerably in length, and having
produced a pair of opposite leaves.

In its vegetative development as well as in its fructifica-
tion and germination, Isoetes exhibits a remarkable agree-
ment with the Lycopods, in the fact that the wood-forming
tissue has no parenchymatous pith in the centre, but
occupies the whole of the longitudinal axis in the form of
a homogeneous woody body. Nageli's investigations* have
shown that in Lycopodiimi a circle of vascular bundles is
visible at first, but that after the differentiation of the
circularly-arranged longitudinal strings of a delicate cam-
bium, the whole of the axile tissue of the stem enclosed by
the latter enters into the formation of the wood, and is
afterwards changed from parenchymatal into prosenchy-
matal cells of various kinds. Thus in nearly allied plants,

* ' Zeitschrift fur Botanik,' H. 3 and 1, p. 140.

372 HOl'MEISTER, OxN THK HIGIIEIl CKYPTOGAMIA.

which exhibit a considerable supplementary longitudinal
development of the internodes, there is found the most
decided tendency to form an axile woody body, similar to that
whose production in Isoetes might — by the omission to
notice the analogous phenomena in the stem of Lycopodium
— be attempted to be brought into causal connexion with
the complete suppression of an intercalary multiplication of
the joints of the stem.

As far as our knowledge extends, Isoetes alone of all the
vascular cryptogams possesses a cambium layer, which is
renewed yearly, and a stem which grows in length both at
the upper and lower ends ; peculiarities of which the one is
rendered necessary by the existence of the other. By the
organization of its stem, especially that of the downward-
growing portion of the wood, Isoetes approaches nearer to
Dicotyledons, — such as Cyclamen and Beta, — which have
undeveloped stem-joints and a stem which does not die from
below, than to the few Monocotyledons with diametrically-
increasing stems, such as Dracaena, Cordyline, and Tamus.
The mode of arrangement of the roots which spring from
the lower portion of the wood of Isoetes answers to that of
the adventitious roots which break forth in vertical rows
from the main root of dicotyledons, a phenomenon which
Schimper and Sachs* have stated and proved to be of uni-
versal occurrence. Some of the commonest plants in culti-
vation, such as turnips and radishes, exhibit such a manifest
regularity in the position and mode of succession of the
adventitious roots, that more certain general results may in
all probability be attained.

* ' Sitzungsber. Wiener Akatl.,' B. xxvi (1858), p. 331.

CHAPTER XIV.

Selaginella.

In the species of Selaginella whose leaves have the 2^
arrangement and stand in pairs opposite to one another in
four longitudinal rows, the form of the growing end of the
stem is that of a cone much flattened laterally. It projects
far beyond the place of origin of the youngest pairs of leaves
(PL LIV, figs. 3, 5, 7"). The multiplication of the cells of
the end of the stem goes on in the young shoot of S. hortensis,
Metten. [denticulata hortul.) until the commencement of
the formation of the third pair of leaves, and in S. Galeoltii
until that of the sixth pair. The multiplication is first pro-
duced by continual division of a single cell occupying the
apex of the blunt cone, by means of septa inclined alter-
nately to the right and to the left, always towards one of
the small sides of the terminal bud. The form of this cell
is that of a segment of an ellipsoid (PI. LIV, fig. 8 ; PI. LVI,
figs. 1, 3). The formation of the above septa, like all the
divisions of the cells of the end of the stem, is preceded by
the disappearance of the primary nucleus of the cell,* the
formation of two new smaller nuclei, and the appearance of
a dark line between the two newly-formed nuclei (PI. LIV,
fig. 9). This line is easily obliterated, even by the continued
action of pure water; its direction indicates that of the
future septum. It is the side-view of the surface of contact
of the two halves of the contents of the mother-cell.

Contemporaneously with the commencement of a new

* This primary nucleus is a globular vesicle floating freely in the fluid con-
tents of the cell which are rendered turbid by numerous granules.

374 HOFMEISTER, ON

division in the apical cell, the second youngest cell of the
stem which adjoins the apical cell divides into two halves
by a longitudinal septum cutting the narrow side of the
terminal bud, and inclined towards one of the wide sides of
the end of the stem (PL LVI, figs. Is, ]/). Each of the two
halves is divided by a longitudinal septum which is concave
towards the septum last formed, and cuts the boundary wall
of the adjoining cell, which latter cell was produced by the
multiplication of the next younger cell of the second degree.
Of the two cells into which each half is thus divided one is
turned towards the narrow, and the other towards the wide
side of the stem. The former is a four- sided prism, the
latter a three-sided one with curved lateral surfaces. The
four-sided daughter-cell then divides, by a septum parallel
to the longitudinal axis of the stem, into an inner and an
outer cell. Frequently in Selaginella Galeottii, less often in
other species, this latter cell-duplication is preceded by the
production of a septum which cuts the upper and the free
outer wall of the cell of the third degree at a very acute
angle (PI. LVI, fig. 3). This mode of cell-multiplication
differs from what takes place in Selaginella denticulate,
helvetica, viticulosa, Martensi, and others, where the more
ordinary cell-succession occurs, and the result of the differ-
ence is, that a half-girdle of wedge-shaped cells is interpo-
lated between each two of the groups of cells produced by
the multiplication of a cell of the second degree. In this
case the division into an inner and an outer cell by a septum
parallel to the axis of the stem, takes place only in the larger,
lower half of the four-sided cell of the third degree.

The three-sided cell of the third degree of the stem of
Selaginella hortensis, helvetica, &c. is divided into two un-
equal parts by the formation of a longitudinal septum
which is attached in a radial direction to the free outer
surface of the cell, verv near to the original side-wall of the
cell of the second degree. The cells produced by the mul-
tiplication of the cell of the second degree are now all
divided transversely by membranes which are parallel to the
former boundary wall between the cell of the second degree
and the apical cell (PI. LIV, figs. 8, 9). This latter divi-
sion usually occurs somewhat later in the inner cells than in

THE HIGHER CRTPTOGAMIA. 375

the outer cells. In Selaglndla Galcottii the like divisions
are produced — by longitudinal septa catting the free outer
surface of the cells — in both parts of the cell of the third de-
gree adjoining the periphery of the terminal bud, i. e. in the
upper wedge-shaped five-surfaced moiety, as well as in the
lower which has six surfaces. Division by a horizontal
transverse septum however only takes place in the inner cell.
By this means the difference in the mode of cell-multiplica-
tion from that which occurs in Selac/inella Jiortensis is re-
moved (PL LVI, fig. 3).*

When the end of the stem is about to become forked
there occur — in addition to the divisions of the apical cell
by septa turned towards the narrow sides of the stem —
divisions by septa inclined alternately towards the wide
sides of the stem. The top surface of the terminal cell
assumes, in consequence, the form of a parallelogram. The
divisions of the apical cell in the four different directions
follow one another in a left-handed spiral, as far at least as
observations go. This second form of the divisions of the
apical cell commences at a very early period in Selaginella
Jiortensis — as early as the commencement of the formation
of the fourth pair of leaves of a segment of a shoot (PL LIV,
figs. 11, 12); in tSelaginella Galeottii and Martensi they
occur much later (PL LVI, fig. 4). In Selaginella Jiortensis
the forking of the stem commences at a very early period.
A transverse section through the end of the stem imme-
diately underneath the apex, exhibits four axile cells, in
which no one of the three directions of space preponderates.
These cells are surrounded by a simple wreath of twelve
cells somewhat stretched in a radial direction. Each two
of them form one of the small sides, each four of them one
of the wide sides of the terminal buds. The laterally com-
pressed form of the stem is visible close under the apex of
its growing end (PL LIV, fig. 7*).

At first the portion of the axis above the youngest leaf
increases considerably in thickness. The number of the

* My former notice of the succession of the divisions was (' Vergl. TJnters.'
p. 112), that the division of each of the halves into an inner and an outer cell
followed immediately after the first division of the cell of the second degree.
Repeated investigations have proved to me that the former division is preceded
by a division produced by an almost radial longitudinal septum.

3/6 HOFMEISTER, OlS

cells of its diameter and circumference is increased by re-
peated division of the two outermost cellular layers of its
lower part, by means of radial septa, and of septa parallel
to the longitudinal axis of the stem. Near the place of
origin of the youngest leaf the longitudinal growth of the end
of the stem of Selaginella denticidata experiences a remark-
able acceleration, by the division of the cells of its outer
surface by means of horizontal transverse septa (PI. LIV,
fig. 8).

The formation of the two youngest leaves commences at
a distance of from eight to ten cells — reckoning down-
wards— from the apical cell of the terminal bud. Two
horizontal opposite rows of cells, each of which occupies a
fourth part of the circumference of the stem, become arched
outwards, and divide contemporaneously by septa inclined
downwards (PI. LV, fig. 21). In the outer three-sided
prismatic ones of the newly-formed cells, division then
ensues by septa inclined in opposite directions (PL LV, figs.
22, 23). The young leaf, viewed from above, now appears
as a narrow seam surrounding a fourth part of the circum-
ference of the stem (PL LIV, fig. V). It grows rapidly in
length by continual division of the cells of its fore-edge by
means of septa inclined alternately towards the upper or
the under surface of the leaf (PL LV, fig. 23 ; PL LVI, fig.
1 2) . This multiplication of the cells is far more active in
the middle of the fore-edge than at its sides. The form of
the leaf would sooner become pointed were it not for the
fact, that the two middle cells of the fore-edge frequently
divide by longitudinal septa perpendicular to the surfaces
of the leaf and slightly diverging from its longitudinal axis.
In the young state of the leaf one such division almost
always occurs after each two divisions by septa inclined to
the surfaces of the leaf. Similar divisions occur from time
to time in the outer of the cellular groups near the middle
of the fore-edge of the leaf (PL LV, figs. 24, 25 ; PL LVI,
figs. 5, C). By this means the originally parallel arrange-
ment of the cells of the leaf becomes radiating and fan-
shaped. By the repeated division of all the marginal cells
of the leaf its base also becomes considerably widened.
The newlv-formed basal cells do not amalgamate with the

THE HIGHER CRYPTOGAMIA. 377

neighbouring cells of the circumference of the stem, but
are developed independently, and form — when the leaf is
perfected — the basal appendages which are especially em-
ployed in the determination of the species. In the greater
part of its area the leaf of SelagineUa Mar tensi and S. Galeottii
continues as a double layer of cells ; only the cells of a wide
longitudinal strip adjoining the median line on both sides
divide repeatedly by septa parallel to the surfaces of the
leaf, alternating from time to time with septa perpendicular
to the surface. Both divisions occur oftener in the inner
than in the outer cells of the longitudinal ribs which are
thus formed, and which project on the underside of the
leaf. The string of narrower cells which thus originates in
the longitudinal axis of the mid- rib is afterwards trans-
formed into a vascular bundle (PI. LVI, fig. 11).

Contemporaneously with the commencement of the thick-
ening of the mid-rib, a longitudinal expansion of the apex
of the leaf begins, an expansion, that is, of the middle cells
of the fore-edge, which by their more frequent divisions
have in the mean time shot ahead of the neighbouring cells.
The walls of these become thickened ; in the place of the
faintly-green mucilage which has hitherto filled the cells,
sharply defined chlorophyll granules make their appearance
in the fluid contents, which have become transparent.
After the commencement of these processes a multiplica-
tion of the superficial cells of the base of the leaf ensues, by
the division of such cells, once at least, by longitudinal
and transverse septa perpendicular to the surfaces of the
leaf. The cells of the under-side divide once oftener than
those of the upper-side, such division being produced by
septa at right angles to the longitudinal axis of the leaf.
In the perfect leaf the cells of the under-side are always about
one half shorter than those of the upper-side, which latter,
instead, divide once oftener by longitudinal septa, so that
they are only half as wide as those of the under-side (PI.
LVII, fig. 8).

The double row of cells of the upper surface of the leaf,
which lies in the angle between the leaf and the stem, and
immediately adjoins the circumference of the stem takes
no part in these divisions. These cells remain consider-

378 HOFMEISTER, ON

ably larger than their neighbours (PI. LVI, fig. 12). Their
free wall becomes arched upwards ; the cell farthest from
the stem then divides by a septum inclined away from the
longitudinal axis of the stem. The double layer of cells
which rises in the form of a wall thus receives an addition
of a row of top cells. These continue to divide by septa
inclined alternately in two directions ; the result is that a
flat membranous cellular body is produced from the upper
side of the base of the leaf (PI. LV, figs. 26, 27 ; PI. LVI,
figs. 11,12). This body was first observed by II. Midler,*
and is a kind of ligulate formation, most nearly resembling,
on the one hand the coronet of the perigone of the Narcissi
and the ligule of the grasses, and on the other hand the
scale in Isoetes. I shall merely call it a stipule.

The cells of the stipule which are raised above the
surface of the leaf very soon divide by longitudinal septa
perpendicular to the upper and under side of the stipule
(PI. LVI, fig. 9), and afterwards also by transverse septa
at right angles to the surfaces of the organ. This multi-
plication continues in the base of the stipule for some time
after the multiplication of the apical cells has ceased (PI.
LVI, fig. 11).

At a later period the number of the cells of the organ in
the direction of the thickness, is increased by the division
of the cells of its lower portion parallel to the surface (PI. LV,
fig. 27; PI. LVI, figs. 11, 12). The double row of basal
cells sunk in the substance of the leaf does not increase in
number, but the cells increase considerably in size. As
the longitudinal growth of the stipule draws to a close, its
apical cells, in BelagineUa Galeottii and others, divide
only by transverse septa perpendicular to the surface. The
upper end of the stipule becomes a simple cellular layer.
The margin, in all species, exhibits a delicate fringe, caused
by the papillate outgrowth of individual cells (PI. LV,
fig. 28). The cells of the stipule contain granular mucilage
which is colourless or grey or — under transmitted light —
of a reddish colour. They never contain chlorophyll.
Like the stipules of the greater number of those phsenogams
in which stipules occur, the development of the stipule of

* 'Bot. Zeit.,'1846.

THE HIGHER CRYPTOGAMIA. 379

Selaginella terminates long before that of the leaf to which
it belongs. It is only to be found in full vitality amongst
the closely crowded leaves of the bud ; in the axils of
those leaves between which the last longitudinal expansion
of the stem began it is always shrivelled and inconspicuous.
Spring, who has written a monograph of the family, has
not himself seen the organ.

That region of the young leaf which, by repeated division
parallel to the surface of the cells of the underside, becomes
transformed into the mid-rib, corresponds exactly in breadth
with the place of attachment of the leaf. This breadth in
the youngest state of the leaf, and up to the time when the
formation of the mid-rib begins, is equal to one fourth part
of the circumference of the stem. It is afterwards much
less, inasmuch as after the commencement of the formation
of the leaf the number of the cells of the circumference
of the stem continues to increase. Each of the transverse
rows of cells of the circumference of the stem — by whose
multiplication a leaf is produced belonging to one of the
four longitudinal rows in which the leaves of the greater
number of the species of Selaginella are arranged — stands
immediately above the place of insertion of the next lower
leaf (PI. LV, figs. 11, 12). The circumference of the stem
becomes thickened as in the Equisetacese by the growth in
thickness of thebases of the leaves,which originate close above
each other, and by the often repeated division, parallel
to the longitudinal axis of the leaf, of the cells of the base
of its under-side. Its periphery appears to be formed of a
number of cellular layers produced by the multiplication of
the cells of the young rudiment of the leaf (PI. LV,
fig. 11). The axile cells of the stem which correspond
with the naked end of the bud — which naked end projects
above the rudiment of the voun°;est leaf — enter for the
most part into the formation of the vascular bundles and
the parenchyma between them.

When the leaf is almost fully formed every other one of
its marginal cells expands laterally into a blunt papilla,
whih becomes rapidly elongated, often to a very consider -
able extent, as for instance at the base of the upper leaves*

* The " Intermediaren Blatter " of Spring.

380 HOFMEISTER, ON

of Selaginella Martensi. The papilla assumes a conical form.
The sharp apex of these unicellular hairs, which represent
the teeth of the margin of the leaf, are soon entirely filled
by rapid thickening of the walls. The conical mass of cel-
lulose often bears a deceptive resemblance to a small cell,
owing to the seam of light which its edges exhibit when
seen with transmitted light (PI. LVI, fig. 7). The two
rows of cells of the upper side of the leaf which immediately
adjoin the marginal cells, exhibit in many species definite
appendages of the outer wall. For instance, S. Galeottii
has two longitudinal rows of bluntish warts, similar to those
on the outer side of the hairs of many Boragineae (PL LVI,
fig. 7).

Numerous chlorophyll-granules are formed in the narrow
cells of the upper surface of the leaf In S. Galeottii and
Martensi they have a distinctly vesicular appearance, and
contain some very small starch granules. In the square
cells of the underside of the leaf the green mucilage
coagulates into a single large spherical ball, as is the case
in Anthoceros (PI. LVI, fig. 8). At the places where the
cells of the under-surface of the leaf adjoin those of the
upper, a connected net-work of air-cavities is produced by
the parting asunder of the edges of contact of the cells of
the under side from the closely connected cells of the upper
side of the leaf. The place of contact of each cell of the
under surface of the leaf with the cells of the upper surface
is surrounded by an air-cavity which is usually six-sided.
Towards the outside the cells of the under-side of the leaf
are in close connexion.

The Lycopodiacese in general, and especially the
species of Selaginella, whose stems are elliptical in a trans-
verse section, afford some of the most marked instances of
true forking of the apex of the stem, which are to be found
in the whole of the vegetable kingdom. In all species
of Selaginella, whose leaves have the 2^ arrangement,
a forking of the stem occurs, almost without excep-
tion,* after each four circuits of leaves ; and the same
thing occurs also in those species whose shoots are appa-
rently quite simple and undivided for a considerable dis-

* The only exceptions I know are seen now and then in S. helvetica.

THE HIGHER CRYPTOGAMIA. 381

tance. Ill 8. viticulosa and cor.difolia also, a rudimentary few-
leaved axis may be found on the lower part of the upright
shoots of the second order which spring from the creeping
stem : it is situated between each fourth upper and under
leaf, and is hidden alternately in the right and left edge
of the stem. If the upright shoot is broken off, these
buds, which otherwise remain dormant, are developed into
upright shoots.

When the end of the stem is about to fork, the apical
cell divides by a vertical septum, instead of by a septum
inclined in the opposite direction to the septum last
formed. In both the newly-formed cells this division is
usually repeated once or several times (PI. LVI, figs. 7°, 9,
10), whilst the number of cells of the next lower portion of
the stem in the direction of the largest transverse measure-
ment of the two edged stem is correspondingly increased by
repeated longitudiual divisions, In the two outermost cells
of the row of cells thus formed which crowns the apex of
the end of the stem, a division ensues by a septum
strongly diverging from the axis of the shoot. The wedge-
shaped one of the two newly formed cells is immediately
divided by a septum inclined in the opposite direction.
Thus the development of two new shoots, in the manner
pointed out in a previous part of this chapter, is brought
about (PI. LV, fig. 10). This happens normally imme-
diately after the commencement of the formation of the
last leaf of the forking shoot, even before these leaves are
clearly visible above the circumference of the stem.

Many species, for instance 8. Martensi, Galeottii, and
viticulosa, exhibit a feature which is found in the Aneurse.
Either the right or the left fork of the stem, alternately,
developes itself more vigorously than the other, and soon
pushes the latter entirely on one side. These species seem
to be furnished with a principal shoot, which sends forth
adventitious shoots to the right and to the left. On the
other hand, in 8. hortensis, helvetica, 8fc, the forks of the
terminal bud are developed quite equally in length and
thickness. The forking end of the stem here assumes at
first the shape of a spatula (PL LIV, figs. la, 10) ; in con-
sequence of the rapid development of the forked shoots con-

382 HOEMEISTER, ON

stituting the edges of the spatula-like flat cellular mass,
the fore-edge of the latter soon appears deeply indented
(PL LIV, figs. 3, 5). Id one respect, however, even here
there is a preponderance of the development of one branch
of the fork ; the right or left fork, alternately, forms
a primary leaf* before its sister-shoot, even before the divi-
sion of the end of the stem is manifest. This leaf, there-
fore, appears to be situated on the middle of the underside
of the forking end of the stem (PL LIV, tigs. 5). By the
subsequent growth of the shoot it is pushed more on one
side.

Each shoot of Selaginella is traversed in its upper portion
by two thin cylindrical woody bundles, whose position
corresponds with the foci of the ellipse represented by the
transverse section of the stem. Towards the base of the
shoot, near the points of junction with the other branch of
the fork, the two bundles unite to form one (PL LIV, fig. 3).
The differentiation of these vascular bundles from the
surrounding tissue of the stem first takes place in Selaginella
Galeottii underneath the second youngest pair of leaves.
The cells destined to form the vascular bundle lag behind
the neighbouring cells in transverse division, and divide
repeatedly by longitudinal septa radial to the axis of the
stem and parallel to it. This takes place even later in
8. hortensis, some time after the commencement of the
forking of the naked end of the shoot in question. In
this species the remarkably regular furcation of the vascular
bundle of each shoot f is manifestly in connexion with the
succession of the forkmgs of the stem.

The cells immediately adjoining the vascular bundles
take no part in the remarkable longitudinal expansion of
the cells of the stem by which the leaves are removed far
from one another, and the first clear distinction between
stem and leaves is produced. The stretching of the neigh-
bouring cells of the bark and of the pith, as well as of the
vascular bundle itself, soon removes those cells from one
another, so that they have the appearance of proportionably
thin threads, which unite the vascular bundle — which is

* Teuille primaire, Spring.

f See ' Kaulfuss Wesen der Famikrauter,' p. 25.

THE HIGHER CRYPT0GAM1A. 383

placed ill the middle of a hollow cylindrical air-cavity —
with the remaining tissue of the stem (PL LVII, fig. 11).
These cells afterwards divide by a transverse septum, once
at least in those species in which the air-cavities have a
proportionably narrow diameter, and several times in those
species where the air-cavities attain a considerable develop-
ment, as in BelagineUa helvetica.

A string of cells passing from the vascular bundles of
the stem through the thickened longitudinal axis of each of
the neighbouring leaves, becomes transformed into a vas-
cular bundle Avhose nature and structure resembles in its
essential features those of the stem. The formation of the
vascular bundles always commences earlier in the stem
than in the leaves ; it progresses from the former towards
the latter (PI. LVI, fig. 11).

Adventitious roots spring from the forks of the stem ; in
S. denticulata and helvetica they spring from each fork, after
the commencement of the final longitudinal expansion of
the stem. In S. Martensi and Galeottii, and still more so
in S. viticulosa the upper ramifications of the upright
shoots, which have a tendency to produce fruit, are apt to
be devoid of roots. The root is always situated in the
angle of the primary leaf, which in the bud apparently
occupies the middle of the forking end of the stem. It
originates on the outer side of the transverse junction which
in the fork of the stem unites the two vascular bundles
(PL LIV, fig. 3). The mode of cell-multiplication in the
growing tip of the root exactly resembles that in the Equi-
setaceae and Polypodiacese ; the examination of it is much
more difficult than in the latter plants on account of the
smallness of the cells. The roots of the Selaginellee, like
those of the Lycopodiacese in general, are usually several
times branched ; they exhibit the most regular furcations
in two directions diverging from one another at about 90°.
The first fork of a root is usually parallel to the surfaces
of the leaf in whose axil it has originated, and the second
at right angles to those surfaces.* The outer side of the
root-cap is often clothed with long papillae, which, as the

* The relation is very manifest in the roots of S. Galeottii, and Martensi
which ramify frequently high above the ground.

384 HOFMEISTER, ON

organ becomes further developed, are thrown off with the
cells which bear them. The adventitious roots of the larger
species fork frequently even long before they reach the
ground. Those of S. kortemis usually ramify for the first
time after they have penetrated into the ground. The
foundation for the first ramification is however here also
laid at an earlier period. The aerial roots as soon as they
have reached a certain stage of development exhibit a
spherical enlargement of the end.* This thickening of the
tip of the root is formed by the commencement of furcation :
the lenticular cell of the first degree of the root has divided
by a longitudinal septum into halves, each of which com-
mences an independent multiplication in a direction away
from the other. The two rudimentary branches thus formed,
surrounded by the outer cellular layers of the root, which
were formed before the commencement of the forking, con-
stitute the almost spherical mass of the end of the root.

It is a known fact that the smallest fragment of the stem
of Selaginella when properly treated — that is, kept moist
and warm upon loose earth — will produce a new plant.
This depends upon the production of adventitious roots in
definite positions : in the angles formed by the vascular
bundles which branch off into the leaves with the vascular
bundles of the stem. The adventitious shoot breaks through
the cortical layer of the stem and is developed into a new
plant by a succession of shoots, in the same manner as
an embryo is produced by impregnation of an archeog-
nium, after an adventitious root has grown out close to its
place of origin (PI. LYI, fig. 10).

Fruit is formed in Selaginella only on particular shoots
differing greatly in their habit from the vegetative shoots.
The branch destined to develope sporangia is, like the
vegetative branches, a fork of the naked end of the shoot
of the preceding order. It is distinguished from the vege-
tative shoots even in its earliest condition by a far less rapid
increase in length, so that, even in Selaginella denticulata,
it is soon pushed to the side of the vegetative shoot — whose
direction is the same as that of the shoot of the preceding
order — and might be taken for an immediate prolongation

* Kaulfuss, Weseii der Farrnkraoter,' p. G4.

THE HIGHER CRYPTOGAMIA. 385

of it (PI. LIV, fig. 3). The mode of cell-multiplication in
the growing end of the fruit-branch resembles that of the
terminal bud of vegetative shoots (PL LV, fig. 29), with
this difference only, that the growth in thickness is uniform
on all sides. The transverse section of the fruit-branch is
circular not elliptical.

A sporangium is produced in the axil of each of the
equal-sized leaves of the fruit-branch — which leaves have
the 2^ arrangement — with the exception of the two or three
first, lowest leaves. The first rudiment of the sporangium
is produced by the division, by means of a septum almost
perpendicular to the outer surface of the terminal bud, of one
of the cells of the circumference of the stem close above the
middle point of the place of attachment of the youngest
leaf. This is followed by the production of septa at right
angles to that surface in the sporangial cells of the second
degree, and of septa parallel to it in the sporangial cells of
the third degree (PI. LV, figs. ], 2). As soon as
the organ has the appearance of a hemispherical lateral
outgrowth of the end of the stem, a central cell may
be seen, surrounded by a simple layer of cells, and borne
upon a short stalk consisting of a few cells. In Selaginella
helvetica this central cell is much larger than its neighbours
(PL LIV, fig. 2). In 8. hortensis the cells which bear it
divide for the first time at a late period by septa parallel to
the longitudinal axis of the sporangium. In this species
the cell in question appears as the uppermost of a string
of cells traversing the axis of the rudimentary sporangium
(R LV, fig. 8).

The enveloping cells divide repeatedly by septa perpen-
dicular to the outer surface of the young fruit, alternating
twice with septa parallel to that surface. The wall of the
sporangium soon becomes a double cellular layer and ulti-
mately a triple one (PL LV, figs. 4 — 6). The cells of the
stalk also divide repeatedly by septa parallel to the longitu-
dinal axis and perpendicular to it ; the stalk of the sporan-
gium rapidly becomes both longer and thicker. In the
mean time the central cell also multiplies, although more
slowly, by repeated bipartitions in all three directions
(PL LX, figs. 4, 5). In a mass of fruit of Selaginella

25 '

386 HOEMEISTER, ON

even the fifth-youngest sporangia have the appearance of a
central group of larger cells (the mother-cells of the spores)
with grumous contents and large nuclei, surrounded imme-
diately by a layer of delicate, mucilaginous, radially-
extended cells, similar to those which surround the string
of mother-cells of the anthers of phamogams. This layer
is followed by a layer of tabular, thick-walled, chlorophyll-
bearing cells, which supports the epidermis of the sporan-
gium : these chlorophyll-bearing cells are radially-extended
prismatic cells with watery fluid contents ; in the young
fruit they are four times smaller than the chlorophyll-
bearing cells immediately below : when the fruit is
almost ripe they are — in consequence of repeated divisions
• — almost sixteen times smaller than the same cells (PI.
LV, figs. 5, 6, 16).

This multiplication of the cells of the young sporangium
takes place mainly in the direction of the breadth ; the
organ assumes the form of a laterally-flattened ellipsoid,
which in the macrosporangia passes by degrees into the
shape of a kidney, and in the microsporangia becomes
more elongated. The leaf in whose axil the sporangium
originates, does not begin to develop its stipule until a
later period, when the young fruit has attained a con-
siderable size, and the central group of spore-mother-
cells has almost completed its full number (PI. LIV,
figs. 3, 4).

The mode of development of the sporangium shows
most distinctly that the latter cannot be considered as a
transformed portion of a leaf, unless * the group of cells
which is formed close above the place of insertion of the
stipule, above the apex of the angle between the latter and
the stem, is considered as belonging to the leaf and not to
the stem. This supposition is only difficult to reconcile
with the observed youngest conditions of the leaf and spo-
rangium. The young rudiment of the fruit, when consist-
ing of only very few cells, is generally situated on the
outer surface of the end of the stem (which outer surface is
turned towards the leaf,) even in those species, like Sela-
ginella helvetica and spimdosa, whose sporangia, when only

* See von Mold ' Vermischte Schriften,' p. 106.

THE HIGHER CRYPTOGAMIA. 387

slightly developed, are pushed so far upwards on the upper
surface of the next lower leaf that they appear to form a
portion of it (PL LIV, fig. 1 ; PI. LVI, fig. 30). In the
vascular cryptogams there are the like difficulties in obtain-
ing a clear idea of the relation of the sporangium to the
leaf, as are met with in observing the relations between the
placenta and ovules of phsenogams, and the carpels. The same
considerations must find a place here, and on this account
I would withdraw my former assent to the explanation * of
the sporangium of Selaginella given by Bischoff, who
described it as a metamorphosed axillary bud, and adopt
von Mold's view, the probability of the correctness of
which is supported by the relation between the sporangium
of Isoetes and its leaf and leaf-scale, the latter being the
manifest analogue of the stipules of Selaginella.

As the sporangium becomes older the spore -mother- cells
become individualised, after a moderate thickening of their
walls. They then form spherical cells with turbid mucila-
ginous contents and a rather large nucleus. They are
closely crowded together and fill the cavity of the fruit
(PI. LV, fig. 6).

Up to this point the history of the development of all
sporangia is the same. Henceforth however, as in all the
Rhizocarpese, the subsequent development exhibits essen-
tial differences, according as the sporangia are destined to
become microsporangia or macrosporangia, i. e. to produce
small or large spores. In Selaginella hortensis the lowest
sporangium only of each mass of fruit becomes a macro-
sporangium ; that one, namely, which is formed in the axil
of the lowest one of that longitudinal row of aristate
leaves which is situated vertically over the last primary leaf
on the right or left side of the shoot of the preceding
order. By the rapid and remarkable increase in size of the
fruit the latter grows beyond the lateral margins of its own
covering leaf, so that the two next lower ones also, which
are sterile leaves belonging to other longitudinal rows of
the fruit-ear, have to take part in covering the fruit.

Of the many free spherical cells of the interior of the
young macrosporangium, one single cell only, not distin-

* « Vergl. Unters.,' p. 119.

388 HOEMEISTER, ON

guished in any respect from the others,* becomes slightly
increased in diameter, its primary nucleus becomes dis-
solved, and four new nuclei are formed. This cell then
divides into four tetrahedral daughter-cells, the special-
mother-cells of the spores, by six septa cutting one another
at angles of 120° (PL LV, fig. 7). Almost immediately
afterwards there is formed in each of the special-mother-
cells a cell almost filling the latter, and having at first very
delicate walls. This cell is the spore. The four spores
immediately begin to become individualised by the gradual
dissolution of the wall of the special-mother-cells (PL LV,
figs. 8, 9, 10), and they assume a spherical form. The
loci of the commissures of the special-mother-cells are
indicated by very slightly prominent ridges (PL LV, figs.
II6, 12*). The product of the dissolution of the special-
mother-cells (which cannot be seen by direct observation)
appears to retain the spores for some time longer in some-
what close proximity.

Soon after the separation of the spores the formation of
the outer spore- membrane commences. The inner trans-
parent layer f is first visible (PL LV, fig. IV), and soon
afterwards the outer one also, which is composed of a quan-
tity of two different substances varying in their refractive
power. Both layers take part in the composition of the
long spines of the exosporium, which are united by reti-
culate ridges (PL LV, fig. 17). During their formation
the three converging ridges at the top of the spore become
somewhat more conspicuous ; each of them now appears
to be traversed by a fine longitudinal fissure. The spines
appear as slight projections of the inner glassy layer
(PL LV, fig. 13), and gradually increase in length. When
quite ripe they appear considerably shorter than when
half-developed. It would seem that the pressure which
the rapidly -growing spores exert upon one another breaks

* In some cases I was convinced that this cell floated almost in the middle
of the macrosporangium. At the time when one of the free spherical cells be-
comes (by division into four) the mother-cell of the spores, the free spherical
cells no longer entirely fill the inner cavity of the macrosporangium ; a space
filled with watery fluid is found above the place at which the stalk is attached
to the capsule.

f Under transmitted light this layer is at first as clear as glass, then straw-
coloured, and ultimately brown.

THE HIGHER CRYPTOGAMIA. 389

off the points of the spines. Shortly before the sponta-
neous rupture of the macrosporangium the spores adhere
rather firmly to its inner wall by means of their spines.

During the formation of the large spores the macro-
sporangium changes its form very considerably. By a
vigorous local multiplication and expansion of the cells of
the wall, two hemispherical protuberances of the latter are
formed in the middle of the two lateral surfaces of the reni-
form sporangium which are turned towards the stem and
the covering leaf. This occurs even long before any one of
the four spores has touched the inner wall of the sporan-
gium (PI. LV, fig. 11"). The top of the organ also becomes
more steeply arched. At this time the spores still float
freely in the watery contents of the macrosporangium, in
company with the numerous unchanged sister-cells of the
one spherical cell, which, by its division, becomes the mother-
cell of the spores. Tour or more of those small delicate-
walled cells are often found still loosely adhering to one
another, a remnant of the innate connexion which in the
earlier stages of development of the sporangium subsisted
amongst the mother- cells. The layer of radially-extended,
mucilaginous, actively-multiplying cells which clothes the
inner wall of the capsule exists up to this time. It disap-
pears with the further development of the spores, and the
wall of the sporangium when almost ripe consists of only
two layers of cells (PL XLI, fig. 16).

The development of the large spores of many other
species, especially of SeJaginella Martensi, helvetica, and
spimdosa, differs from that above described, especially in
the fact that the special-mother-cells last much longer than
in S. hortensis. The spore has therefore (even when fully
developed) a somewhat sharply defined tetrahedral form
(PI. LV, fig. 13 ; PL LVII, figs. 6, 7), at least its apex ex-
hibits three very distinct ridges, meeting at angles of 120°,
and extending downwards for a considerable distance ; this is
the case in S. helvetica. The species in which this occurred
are all species in which the macrosporangia and microspo-
rangia, differing little if at all in their external form, are
intermixed apparently without regularity. In Selaginella
Galeotlii even the very young large spores have a regular
spherical form. In 8. Martensi a considerable increase in

390 HOFMEISTER, ON

size takes place in that one of the many free spherical cells
in the interior of the young capsule which is destined to
become the mother-cell of the large spores (PI. LVII, figs.
1 — 5). Four new spherical nuclei (PI. LVII, fig. 3) are
formed on the outside of its primary nucleus, which becomes
more and more indistinct. Soon afterwards the primary
nucleus disappears (PL LVII, figs. 4, 4*), and six septa
meeting at angles of 120° suddenly appear in the mother-
cell (one between each two of the secondary nuclei), which
represent four tetrahedral special-mother-cells. In each of
the latter a spore is formed after a previous considerable
thickening of the wall, and during the very remarkable
increase in size of the special-mother-cells which follows this
thickening. The brown exosporium is in this species very
thick. In the perfect state three layers are distinguishable,
the middle one of which is of a glassy nature. The thick-
ened special-mother-cells are still in a good state of preser-
vation. The lines of division between each two are here
far more clearly distinguishable than in any phamogamous
plant except the Malvaceae (PI. LVII, fig. 7). At this stage
of development a slight pressure separates the special-
mother-cells, each of which contains a spore (PI. LVII, fig.
7b). In a manifestly diseased state of S. Martensi I have
seen the disproportionately thick exosporium composed of
prismatic (or, to speak more accurately, of truncate-pyramidal)
fragments ; the spore had remained much smaller than usual
(PI. LVII, fig. 8).

During the formation of the outer membrane of the large
spores of all the species which I have examined, the spheri-
cal nucleus usually lies close under the place at which the
three prominent ridges of the exosporium unite (PI. LVII,
fig. 7).* It increases rapidly in size, and its nucleolus
disappears. Afterwards numerous vesicular bodies appear
within it (PI. LV, figs. 13, 14). As the spore approaches
maturity it appears to be dissolved : I was never able to
find it in those spores which entirely fill the macrospo-
rangium.f

* If the young spore lies for some time in water, the nucleus disappears.

f Metteuius appears to assume that the nucleus of the spore gradually expands
until it attaches itself at all points to the inner wall of the spore-cell ('Beitr.
zur Botanik,' H. i, p. 7). I have never seen anything indicative of such a
process.

THE HIGHER CRYPTOGAMIA. 391

Iii the microsporangia all the free spherical cells of the
interior divide at a somewhat early period into four tetra-
hedral special- mother-cells. The process is similar to that
which takes place in the division of the mother-cells of the
large spores of Selaginella Martensi. Four new smaller
nuclei are formed outside the primary nucleus of the cell,
apparently by the double bipartition of a spherical accumu-
lation of formative matter. Between each two of them the
six double walls appear which separate the individual special-
mother-cells from one another. The commissure of the
septa of each two special-mother-cells is often very percep-
tible even in the mother-cells of the small spores, notwith-
standing the minuteness of the object (PI. LVII, fig. 10*).
In each of the special-mother-cells a spore is formed, which
in many species (for instance in 8. Martensi) produces
wonderfully long spines on the outside of the exosporium
after the absorption of the special-mother- cells. On the
other hand the outer membrane of other species, such as S.
helvetica, appears only slightly granulated. All small spores
of Selaginella exhibit at the apex three converging ridges
of the outer spore-mernbrane. In the microsporangia of
cultivated tropical species of Selaginella, malformations are
not uncommon. Thus in S. Martensi it frequently happens
that a mother-cell divides into two or three special-mother-
cells only,* of which three, two only produce spores (PI.
LVII, fig. 11); or sometimes, out of a mass of special-
mother-cells, two or even three become shrivelled, whilst
the rest retain their vitality. In one case I saw the follow-
ing singular phenomenon. In one sporangium, containing
several abortive and several apparently healthy sets of
mother-cells, eight oval cells occurred, more than three
times as large as the largest special-mother-cells, and having
a disproportionately thick, glassy, transparent wall, which
exhibited manifest lamination : the cell-contents consisted
of concentrated granular mucilage and a rather large nucleus
(PL LVII, fig. 12).

The large spores only of the Selaginellae produce pro-
thallia. The first rudiments of the latter are formed before

* As in 11. Browa's Triposporium.

392 HOFMEISTER, ON

the bursting of the macrosporangia. A circular simple
cellular layer appears spread over the inner side of the pri-
mary spore-membrane, underneath the point in which the
four special-mother-cells of the spores touch one another.
Those cells are of the greatest height which are situated in
the middle of the cellular layer underneath the point of
junction of the three projecting ridges of the outer spore-
membrane; they divide very soon by transverse septa.
Towards the periphery the cells gradually diminish in height ;
the outermost have the form of a procumbent wedge (PI.
LVII, fig. 16). In many species, especially A7, hortensis
and helvetica, the rudiment of the prothallium when seen
from above appears to have no distinct boundary, inasmuch
as the outermost edge of the marginal cells formed by the
convergence, at a very acute angle, of the upper and under
wall of the cell, does not refract transmitted light much
more powerfully than the primary wall of the spore itself.
The marginal cells of the prothallium when seen from above
appear open towards the outer side (PL LVII, fig. 17).*
The prothallia of other species, for instance of 8. Martensi,
exhibit nothing of the sort (PI. LVII, fig. 18).

I have not yet made out the first stages of development
of the rudiment of the prothallium. It is uncertain
whether it is formed, like the prothallium of Marsilea, by
repeated bipartition of a single cell, or whether, like

* I believe that the above explanation is sufficient to explain the peculiar
phenomenon. Metteuius ('Beitr. zur Botanik/ Part 1, p. 10), deduces from
it a mode of development of the cells of the prothallium, which would differ very
widely from all other phenomena hitherto observed in the vegetable kingdom.
He believes that the prothallium originates between two lamella? of the wall of
the spore, which separate from one another ; that it increases gradu-
ally in circumference whilst those lamellae become further separated from one
another, and that new cells are added to the circumference of the prothallium
in a manner which — even if it is not yet fully investigated — offers no points of
resemblance with the hitherto better known forms of cell-formation. 1 consider
Mettenius's conclusions to be incorrect, especially because the small-celled por-
tion of the prothallium from which the archegonia are produced occupies when
fully developed (PI. LVIII, figs. 1, 4), no relatively greater portion of the cir-
cumference of the spore than it does when it first becomes visible. I consider
it much more probable that the empty cells figured by Mettenius in fig. 10 of
the first plate of his work, should be cells, which, by the development of the
large-celled inner portion of the prothallium have been pressed against the
outer spore-membrane, and squeezed together so as to obliterate the cavity,
than that they should be cells in a formative condition.

THE HIGHER CRYPTOGAMIA. 393

the endosperm of the Coniferae — which in so many
respects resembles the prothallium of Selaginella — it is
formed by the attachment of originally free cells to the
inner wall of the large spherical firm-walled cell (the spore
or embryo-sac) in which it originated.

In the above state the large spores are discharged from
the ruptured macrosporangium. In S. hortensis and hel-
vetica their further development is preceded by a dormant
condition which lasts for several months. During the latter,
the walls of those cells of the prothallium which adjoin the
spherical inner cavity of the spore become thickened. Thick-
ening layers are formed on both their sides, leaving, in some
cells, wide circular pits free (PI. LVIII, figs. 1, 2). By
taking longitudinal sections of these pits it is seen that the
thickening of the walls is most considerable on that, surface
which is turned towards the interior of the spore. The
contents of this large spherical cell secrete cellulose and
cause a thickening not only of the septa which separate the
contents from the cells which have attached themselves to the
inner wall of the apex of the spore, but also of the free
portion of the inner surface of the primary spore-membrane,
so that the latter becomes a very compact glassy membrane
^o'" thick. The contents of the large cavity of the spore
consist during this period of a mixture of albuminous and
oily matter. These phenomena are most remarkable in S.
hortensis, less so in S. helvetica. In S. Martensi and other
tropical species the large spores germinate a few weeks after
being sown, and the above thickenings of the walls are
hardly perceptible (PI. LVII, fig. 19).

When the further development of the prothallium com-
mences, its cells divide repeatedly by longitudinal septa
perpendicular to the outer surface, and by transverse septa
parallel to that surface. This cell-multiplication begins
in the middle point of the prothallium, proceeds from
thence towards the periphery, and ceases long before it
reaches the latter (PI. LVII, fig. 6). Before the repeti-
tion of the division by transverse septa archegonia are
formed.

The first archegonium appears exactly at the apex of the
prothallium ; those which are lower down are of later origin.

394 HOFMEISTER, ON

The formation of the archegonium commences by the division
by means of a transverse septum of one of the cells of the
upper side of the prothallium. This is followed by the
division of the upper cell by a longitudinal septum, and the
division of the two halves by a septum at right angles to
the one last formed and perpendicular to the free outer
surface. Each of the four narrow tall cells which are situ-
ated above the larger basal cell, is divided by a horizontal
septum into two parts of which the under half is usually
the lower in height (PI. LVJII, fig. 1). The four apical
cells of the archegonium generally arch out into short
papillae (PL LVIII, fig. 2). By the parting asunder at
their edges of contact of the four parallel pairs of cells, a
narrow passage is formed, leading to the basal cell (PI.
LVIII, figs. 1*, 4). In the latter a spherical cell is pro-
duced almost filling the mother-cell and rich in finely
granular protoplasm. All the narrow cells of the pro-
thallium now exhibit distinct nuclei if sufficiently fine sec-
tions be taken. The outer walls of the cells of the upper
side, especially those of the apical cells of the archegonia
appear at this time remarkably thickened (PI. LVIII,
fig. 2).

Contemporaneously with the development of the arche-
gonia a tissue of wider cells becomes visible spread over
the under side of the small-celled portion of the prothallium
(PI. LVIII, fig. 1). The middle of this cellular mass pro-
jects into the unoccupied portion of the inner cavity ; it
hangs downwards from the inner wall of the primary spore-
membrane for some distance beyond the first-formed por-
tion of the prothallium. Its marginal cells repeat the form
of that of the older cellular layers ; they are wedge-shaped,
and their under side forms a very acute angle with the inner
wall of the spore. In 8. Martensi a similar large-celled
tissue fills the entire cavity of the spore-cell.

There is only one species, viz. 8. helvetica, in which I have
been able to ascertain the behaviour of the small spores
after they are set free. In this case however there was no
doubt. Five months after the beginning of March, at
which time they were sown upon earth mixed with fine
sand and kept continually moist, a large number of very

THE HIGHER CRYPTOGAMIA. 395

small * spherical cells were formed in almost every small
spore, and nearly filled its cavity (PL LVII, fig. 13). By
careful pressure these cellules escaped through the fissures
of the ruptured spore-membranes. They contained either
a finely granular protoplasm,! or a very fine, thin sperma-
tozoon, rolled up spirally, which when free moved slowly
(PL LVII, fig. 15).

The production of spermatozoa in the small spores termi-
nates long before the complete formation of the prothallium.
In S. helvetica, as has been said, it ceases five months after
the sowing of the spores, whilst the first archegonia on the
prothaliia of large spores sown at the same time, did not
appear until six weeks later. This is no doubt the reason
why all experiments with the large spores yield no result —
whether sown separately or mixed with the small spores —
where the possibility of the subsequent access to the pro-
thaliia of small spores of the same species, is precluded, £
The young plant or embryo is formed by the repeated
bipartition of the one daughter-cell produced in the basal
cell of the archegonium. It does not often happen that
more than one archegonium of the same prothallium is im-
pregnated. The abortive archegonia, especially those low
down on the prothallium, often exhibit a peculiar luxuriant
growth of their apical cells § (PL LVIII, figs. 4, 5). The
first division of the mother-cell of the embryo (the germinal
vesicle) takes place by a transverse septum (PL LVIII,
fig. 3). ||

It happens occasionally but rarely that the embryo origi-
nates immediately from the lower of the two cells, and that
all its daughter-cells take part in the formation of the
massive portion of its first axis (PL LVIII, fig. 6).- The

* Diameter gjg'" or less.

f See PI. LVII, fig. 13. I consider these cellules as not fully developed.

% When I sowed the large and small spores together, and covered them with
a hand-glass, all the sowing failed. Spring was similarly unsuccessful (' Mono-
graphic de la famille des Lycopodiacees,' extraite des tomes xv et xxiv des 'Me-
moires de I'Academie Royal de Belgique,' Bruxelles, 3 842 et '49, p. 316, note).
Ou the other hand when richly-fruiting specimens of the same Selagiuella were
brought under the hand-glass, embryos soon appeared.

§ Tiie process is very accurately explained by Mcttenius, 'Beitrage,' Part 1,
p. 12.

|| See the note to this figure in the explanation of the plates.

396 HOFMEISTER, ON

commencement of the formation of the first axis — which
takes place by division of the terminal cell of the short pro-
embryo by alternately inclined septa — is usually preceded
by the division (from once to three times) of the terminal
cell of the bicellular pro-embryo (embryo-bearer) by trans-
verse septa. During this process a very considerable
longitudinal expansion of the upper cells of the pro-embryo
takes place, in consequence of which its lower end is pushed
deep down into the tissue of wider cells, which tissue in
S. liortensis now fills about a third part (PI. LY1II, fig. 4),
and in S. Martensi the whole of the cavity of the spore.

By the multiplication in manner above mentioned of the
terminal cell of the pro-embryo, the first axis of the embryo
is formed. In S. liortensis, after a very short longitudinal
development, the number of the cells of this axis increases
no further ; on the other hand an adventitious axis shoots
out from one of its sides destined to break forth from the
prothallium and to produce the first pair of leaves of the
embryo (PL LVIII, figs. 7 — 10). The form of the growing
end of this shoot, as well as the mode of its cell-multiplica-
tion, is exactly that of the subsequent vegetative axes above
described. Its growth is directed obliquely upwards.
During its longitudinal development, the end of the primary
axis of the young plant, which in S. liortensis is hitherto
hardly perceptible, increases somewhat in size, more by the
expansion of its cells than by their multiplication (PI. LVIII,
figs. 7, 10).

Before the shoot of the second order has pierced through
the lower, wide-celled layer of the prothallium, it produces
two opposite leaves, by the contemporaneous division of
horizontal rows of cells of its wide lateral surfaces. After
the shoot has emerged to the light these leaves are developed
and produce chlorophyll in their cells. The arrangement
of their cells exactly corresponds in all stages of develop-
ment with that of the primary leaves of vegetative shoots.
In the germ-plants of all the species which I have seen,
these leaves bear appendages on both sides of their base.
In their axils adventitious leaves are formed, precisely
similar to those produced at a later period (PI. LVII,
fig. 22). Not long after the appearance of the first pair of

THE HIGHER CRYPTOGAMIA. 397

leaves the naked terminal bud above them becomes forked
(PL LVII, fig. 22). Now, or soon afterwards, the cells of
the lower portion of the axis of the second order undergo a
sudden and considerable longitudinal expansion, and thus
break through the small-celled upper half of the prothallium.
The two leaves spread out expand in length and breadth,
and become green.

At the same time the two axes of the third order, into
which the end of the axis of the second order has divided,
commence their further development. Their cells multiply
rapidly in a longitudinal direction, and produce leaves.
The four longitudinal rows of leaves do not appear con-
temporaneously upon the shoots of the third order. A
lower first leaf appears without an opposite upper leaf. The
next leaf which is a lower leaf of another longitudinal row,
is also often without an opposite upper leaf. From thence
upwards the arrangement of the leaves is regularly
2^. The longitudinal expansion of the two shoots of
the third order (like that of the subsequent vegetative
shoots) commences, in Belqginella hortensis, for the first
time, when their ends begin to fork for the formation of
the axis of the fourth order, and the result is that these
leaves of the shoots of the third order are for some time so
closely crowded, as to appear upon a cursory examination
to belong to the axis of the second order, with whose two
leaves they seem to form angles of different divergence.

The first adventitious root springs out of that side of the
axis of the first order which lies opposite to the place of
origin of the shoot of the second order. It corresponds in
development and structure most completely with those after-
wards produced. In Selaginella hortensis it is usually
first developed at a very late period, at the time of the
commencement of the longitudinal development of the
axes of the third order. Exceptions to this are of
rare occurrence. It appears much earlier on the germ-
plant of S. Marten si ; even whilst the embryo remains
within the lower layer of the prothallium (PI. LVII,
fig. 20). In the latter species the end of the primary axis
is far more fully developed than in the former.

398 HOFMEISTER, ON

111 the mode of cell-multiplication, the succession of the
shoots, and the development of the leaves, Lycopodium* comes
much nearer to the Polypodiacese (for instance to Aspidium
filiso-mcts) than to Selaginella, The terminal bud which is a
conical wart, extends somewhat beyond the place of origin of
the youngest leaf. The division of its apical cell, as well as
the multiplication of the cells of the second degree, resembles
the same process in Aspidium. The leaf appears to be
formed by the multiplication of a single cell of the circum-
ference of the terminal bnd. It grows in length by divi-
sion of an apical cell by septa inclined alternately towards
the upper and the under surface of the leaf. Here also it
is easily seen that the cells of the base continue to divide
long after the multiplication of the cells of the tip of the
leaf has ceased. Ramifications of the stem occur by the
forking of the terminal bud above the place of origin of
the youngest leaf.f The growth of the roots exactly re-
sembles that of the adventitious roots of the Polypodiacese,
the Equisetacese, and the Pilulariae.

Psilotiim triquetrum is exactly like the Selaginellse in the
mode of forking its terminal buds. This plant also re-
sembles Selaginella viticulosa, and still more so S. cordifolia,
in the relation of the annual shoots to the buried perennial
stem.

The growth of the stem of Psilotum results from the
repeated division of a single apical cell by means of septa
inclined alternately in different directions. The growth of
the .leaves in the first stages of development resembles that
of Lycopodium. Afterwards a forking of the tip of the
leaf takes place.

The reproduction of those Lycopodiaceas which bear
powdery spores of one kind only is still a mystery. Re-
peated sowings of the spores of Lycopodium clavatum,
L. inundatum, and of Selago, have yielded me no results, but
I have lately often observed that in spores of Lycopodium
Selago, which had been sown for from three to five months,
numerous small spherical ceUs had been formed, similar to

-* I have particularly examined lycopodium inundatum.

f Compare Nageli, ' Zeitschr. f. Botanik/ Parts 3 & 4, PL.v, fig. 1.

THE HIGHER CRYPTOGAMIA. 399

the mother-cells of the spermatozoa of Selaginella helvetica.
I have not yet found spermatozoa inside these vesicles. De
Bary has lately discovered (' Berichte der naturf. Gesellsch.
zu Freiburg,' IS 58, p. 467), that the spores of Lycopo-
dium inundatum produce a body composed of a few cells,
whose structure is not unlike that of the arches-onium of a
fern. It is probable from these observations that the
similarly formed spores of Lycopodium, Psilotum, &c, are
of different sexes, and as in Equisetum arvense produce
partly archegonia and partly spermatozoa.

Of late years the Lycopodiaceae have received less atten-
tion from vegetable anatomists than any other of the
higher cryptogams. Since the appearance of those parts
of BischofPs ' Cryptogamische Gewachse,' which relate to
these plants, few papers on the subject have been pub-
lished. Karl Miiller's observations (which however are full
of errors), are to be found in the ' Botanisehe Zeitung' for
1846, besides which we have Nageli's work cited above, and
Mettenius's history of the origin of the embryo of 8. invol-
vens. Spring's monograph is devoted principally to the
limitation of the species.

CHAPTER XV.

CONIFERiE.

The ovules of the Coniferse, however much they may differ
in their position and mode of attachment, exhibit the greatest
uniformity in their internal structure. A simple, some-
what fleshy integument, surrounds a short and thick nu-
cleus formed of delicate cellular tissue, leaving open a
wide micropyle-canal. In the anatropal ovules of the
Abietinese the division between nucleus and integument
extends downwards only for a short distance (PI. L1X,
fig. 10) ; the mouth of the ovule widens considerably above
the apex of the nucleus, parallel to the spermophore, and
appears as a transverse fissure. In Finns sylvestris and
JP. strobus the nucleus exhibits a very remarkable depression
of its apex; in Finns balsamea (PI. LIX, figs. 10, 11),
the depression is less manifest. The nucleus in Juniperus
and Thuja increases in diameter towards the apex : in
both, the apex exhibits a depression, which however in Juni-
perus is but slight (PI. LXIV, fig. 5). Lastly, the nucleus
of Taxus, which is far larger than that of any other indi-
genous Conifer, is quite like that of most phaenogams,
in its oval form, and in the separation between its nucleus
and integument, which extends to the base of the ovule
(PI. LXIII, fig. 1).

The nucleus at the time of the shedding of the pollen
consists of delicate-walled cells filled with granular muci-
lage. Deep in its interior — in the Abietinese and in Juni-
perus, underneath the place where the integuments and
the nucleus amalgamate; higher up in Thuja, and still

H0FMEISTER, ON THE HIGHER ORYPTOGAMIA. 401

higher in Taxus — certain of the cells (in the Abietinege
and in Juniperus rarely more than one)* of the middle
longitudinal string of the cellular tissue of the ovnle become
the embryo-sacs (PI. LIX, figs. 10 — 12). In the ovule of
Taxus a short row of cells, usually consisting of three cells
of the axile cellular string of the nucleus, is distinguished
from the neighbouring cells by their size, and by their
containing an abundance of granular mucilage mixed with
small starch-granules (PL LXIII, fig. 2). Of these cells
sometimes one, sometimes each one of the three is deve-
loped into a perfect embryo-sac; Taxns, at first, always
exhibits more than one. The cellular layers immediately
surrounding the embryo sac are strikingly distinguish-
able from the rest of the tissue of the ovule by their more
delicate cell-walls, and by the greater concentration of the
mucilaginous contents.

The first stages of development of the pollen of the
Coniferse, from the individualization of the mother-cells up
to that of the pollen-cells, correspond exactly with the
ordinary type of phamogams. The young anther of Pinus f
appears at the end of the autumn preceding the flowering
season as a short, spatula-shaped scale, convex below.
On its under-side, near the base, two oval protuberances
are to be seen : these are the lobes of the anthers. Each
lobe is filled with a firmly- connected tissue of rather large,
delicate- walled cells, the mother-cells of the pollen. Each
of these cells contains a spherical nucleus, occupying about
one half of the cell-cavity, and having rather transparent
fluid contents, and several very small nucleoli. The rest of
the cell-cavity is occupied by a gelatinous mucilage in
which numerous very small starch-granules are embedded.
Tincture of iodine colours this mucilage a pale yellow, and
the coagulating fluid contents of the nucleus a deep brown.
Two layers of tabular cells form the entire outer covering
of the mass of mother-cells ; the layer of horizontally

* There are trees of Pinus syhestris (one for instance in a marshy spot in the
Botanical Garden at Leipzig) which, like the yew, develops two embryo-sacs in
most of their ovules.

f The species which 1 examined were P. sylvestris, maritima, Larix, and
balsamea.

26

402 HOFMEISTER, ON

expanded cells which occurs in so many monocotyledons
and dicotyledons is altogether wanting in the Coniferee.

The mother-cells remain during the winter in the state
described. At the commencement of the warmer season
the connexion between the mother-cells is dissolved. This
occurs in Pinus sylvestris at the beginning, and in
P. maritima in the middle of April. The membranes of
these cells become thickened, and one or two of the
nucleoli have increased in size. In Pinus balsamea this
growth is far more considerable than in Pinus sylvestris,
where sometimes all traces of the nucleoli have already
disappeared. The fluid substance of the nucleus coagu-
lates very easily under the action of water, even more
rapidly than in Tradescantia. The viscid fluid contents of
the cell then appear most clearly distinct from the spherical
cavity, which was filled by the nucleus before the latter
became coagulated and contracted into a spherical ball.
In Pinus Larioc the slight tendency of the cell-fluid to
absorb water and become swollen — which is the cause
of the appearances above mentioned in P. balsamea —
exhibits itself in a different manner. The membrane of
the mother-cell swells rapidly in water, and is lifted away
from the cell-contents, the original volume of which is not
increased.

The dissolution of the nucleolus or nucleoli soon ensues,
as well as that of the nucleus, just in the same wray as in
Tradescantia, Lilium, Iris, Passiflora, &c. In the homo-
geneous fluid contents of the cell, two large flattened
elliptical nuclei are next formed. The fluid substance of
the latter refracts light in almost exactly the same manner
as the fluid contents of the cell, from which it can only be
distinguished with much difficulty. At their first appear-
ance these nuclei never contain nucleoli (PL LIX, figs. 2 — 4).
Nucleoli — especially in Pinus balsamea — are first produced
at a later period, contemporaneously with the distinct defi-
nition of the limits of the cell-fluid. These nucleoli are
always very numerous, sometimes there are as many as twenty.
The nucleoli produced from the nucleus of a ruptured
mother-cell of P. balsamea were coloured blue by diluted
tincture of iodine, proving themselves to be starch- granules.

THE HIGHER CRYPTOGAMIA. 403

The numerous amyloid granules of the cell-sap, accumu-
late, after the production of two secondary nuclei, in the
form of an annular girdle in the equator of the cell. This
girdle soon divides into two, parallel to one another
(PI. LIX, fig. 3). The division of the cell-contents into
two halves appears thus to be indicated. These conditions
are so frequent that I do not doubt they must occur in all
mother-cells. The further formation, however, takes place
in two different ways. The case of least frequent occur-
rence is as follows : — A delicate line suddenly appears in
the equator of the cell between the two girdles of granules,
which line immediately disappears under the action of
strong reagents. I believe the line to indicate the surface
of contact of the two membraneless halves of the cell-
contents produced by the division of the contents of the
mother-cell. Shortly afterwards a circular rido;e makes its
appearance, seated upon the inner wall of the mother-cell
and traversing its equator, and forming as it were a frame to
the septum of the two special-mother-cells of the first degree
wrhich are in course of formation. The other case above
alluded to, and which is the one of ordinary occurrence, is
the following: — The division of the primordial utricle is in-
terrupted by the fact that the membranes of the secondary
nuclei are absorbed, and in the place of each one of them,
two — making four altogether — perfectly spherical nuclei are
formed, which either lie in one plane, or are arranged at the
angles of a tetrahedron. Between each two of these,
flattened accumulations of granules are produced, in each
of which a delicate line suddenly becomes visible, which is
the first indication of the septum dividing the two special-
mother-cells.

After the formation of two special-mother-cells of the
first degree, two cells are formed in each of them, so that
then each set of special-mother-cells consists of four.

Finns Larix differs somewhat from other Coniferse in the
circumstance that in one way or another more than four
special-mother-cells and pollen-cells are frequently, in fact
almost always, formed in one mother-cell. The usual
number is six, and the occurrence of seven or eight is
not unusual (PI. LIX, fig. 6).

404 HOFMEISTER, ON

In Juniperm and Thuja occidentalis the phenomena of
cell-division are exactly the same as in the above-named
plants. In the former, however, on account of the small-
ness of all the parts, and in the latter, owing to the abun-
dance of starch- granules in the cell- contents, the obser-
vations are rendered much more difficult.

In each special-mother-cell a pollen-cell is formed, which,
when its membrane first becomes visible, entirely fills the
cavity of the former. The two layers of the membrane of
* the pollen-cell, the intine and the extine, are clearly distin-
guishable whilst the pollen-cell is still enclosed in the
special-mother-cells. The rudiments of the two hemi-
spherical appendages of the extine which are characteristic
of Abies pectinata, Picea vulgaris, and Pinus sylvestris, are
formed whilst the pollen-cell is still within the special-
mother-cell. These appendages consist, when in the young
state, of a soft inner substance, which passes on the outside
into a firmer cortical layer composed of reticulate ridge-like
protuberances. By the use of any fluid which attracts
water, such as a solution of sugar, the inner substance is
contracted into a smaller space, and the cortical layer of
that portion of the appendages which is furthest from the
middle point of the pollen-cell is made to turn inwards.

After the pollen-cells have become free by the dissolution
of the walls of the mother- and special-mother-cells, a cell-
multiplication commences in them which is quite peculiar
to the gymnosperms, and is not seen in any other phaeno-
gams. Two nuclei suddenly appear in the cell — a spherical
one, similar in all respects to the original nucleus of the
pollen-cell, and one somewhat smaller of a very flatly-
lenticular form (PL LIX, fig. 7). It is hardly a matter of
doubt that the latter is newly formed by the side of the
primary nucleus of the pollen-cell. Soon afterwards the
two nuclei appear separated by a membrane, convex towards
the larger one, having the form of a segment of a spherical
surface, and which divides the pollen-cell into two unequal
parts. That part which contains the flattened nucleus is
the smaller one. The disproportion in size of the two
parts is inconsiderable in Pinus Larix (PI. LIX, fig. 8),
but very remarkable in Picea vulgaris and Pinus syhestris.

THE HIGHER CRYPTOGAMIA. 405

In the Abietineae the lenticular daughter-cell of the
pollen-grain increases rapidly in size, and divides twice by
septa convex towards the middle point of the pollen-cell.
When the pollen-grain is ripe a cellular body is found
at one end,* projecting far into the cavity of the pollen-
grain, and consisting of a large vesicle borne upon a stalk
consisting of two low meniscoid cells. In Pinus Larix
this body fills more than half the cavity, and in Picea vul-
garis and Pinus sylvestris it fills the latter almost entirely
(PL LIX, fig. 9).

The inner membrane of the pollen-cell exhibits, even in
the young state, a great capacity for distension, so that
when placed in water the intine swells into a wide layer,
which stretches the extine and compresses the cell- contents.
After the pollen-grain is ripe this peculiarity is intensified ;
thus, for instance, when the detached pollen of Pinus syl-
vestris is moistened with water, the extine is immediately
ruptured, and frequently entirely stripped off.f

The development of the pollen of Juniperus, Taxus, and
Thuja appears to be similar in all respects to that of the
Abietinese, but the smallness of all the parts, and the want
of transparency of the cell-contents interferes very much
with the examination in these plants. The perfect pollen-
grain of Juniperus, Thuja, and Taxus appears to be divided

* That end which corresponds with the point of contact of the pollen-cell
with its sister-cell. In Pinus Larix the daughter-cell lies in the more pointed
end of the oval pollen-cell : in Pinus sylvestris and Abies pectinata it lies on the
longest edge of the pollen-grain, in the middle part of that side which lies oppo-
site to the side which bears the two hemispherical appendages of the extine.

f The structure of the pollen of the Abietinea? was correctly understood and
described by Pritzsche ('Mem. Acad. St. Petersbourg p. divers savants,' III
(1837), p- 693). He states that at the one pole of the somewhat ellipsoidal
pollen-grain of Pinus Larix, the outer one of the two layers which compose the
inner membrane encloses a cavity filled with granular matter, underneath which,
in a depression of the inner layers of the intine, a second similar but more sphe-
rical cavity is found; to the latter is attached a closed vesicle, filled with
fovilla, which projects into the interior of the pollen-grain. Pritzsche in like
manner ascertained the structure of the pollen of Pinus sylvestris — a more diffi-
cult matter — only here the central vesicle appeared to him to be altogether
wanting. Schacht ('das Mikroskop,5 2nd edition, Berlin, 1855, p. IIS) ex-
plained that in P. sylvestris the vesicle in question entirely fills the cavity ; he
pointed out also that in the Coniferee it is not the inner membrane of the pollen-
grain, but the above vesicle — the terminal cell of the short row of cells which is
attached to one pole of the pollen-grain — which grows out and forms the
pollen-tube.

406 HOFMEISTER, ON

into only two unequal cells ; it is probable that the larger
of the two is the terminal cell — expanded so as entirely to
fill the pollen-cell — of the short row produced by the
multiplication of the smaller portion of the pollen-grain.*

The cell-multiplication in the interior of the pollen-grain
of the Conifera3 takes place very rapidly ; in the space of a
fewT clays ; I observed it, for instance, in Finns Laricc,
in the year 1855, to last from the 27th of March to the
10th of April.

The pollen of the Coniferae passes through the wide
micropyle directly on to the nucleus. Each pollen-grain
sends out into the tissue of the latter — at first only for a
short distance — a tube formed by the prolongation of the
terminal cell of the short row of cells attached to its inner
wall. In Taxus and Juniperus this tube is emitted shortly
after the shedding of the pollen, in the Abietinese not until
after remaining dormant for many weeks. The formation
of pollen-tubes takes place in Pinus sylvestris, Muglius, and
austriaca at the beginning of June, in P. Strobiis somewhat
later. In a few days they penetrate at the utmost not
farther than near to the place where the integument sepa-
rates itself from the nucleus (PI. LIX, fig. 14); then, and
not unfrequently even sooner, their longitudinal growth
ends for the first time (PL LIX, fig. 17). Up to this point
the embryo sac remains a simple cell, whose large nucleus
is gradually dissolved (PI. LIX, fig. 14). Some days later
however numerous free nuclei appear in its interior
(PL LIX, fig. 15), and immediately thereupon it appears
filled by a large number of radially-elongated cells arranged
in a concentrical layer (PL LIX, figs. 16, 16J), which mul-
tiply actively in all three directions until the commence-
ment of the winter rest. The primary wall of the embryo-
sac has in the mean time become so thin and delicate that
it almost disappears from observation. At the same time
a considerable multiplication of all the cells of the nucleus

* The pollen of Ephedra behaves exactly like that of Lark (see Schacht,
cdas Mikroskop/ 2nd ed., 1855, p. 148); the pollen of the Cycadese on the
other hand appears unicellular when ripe. Possibly stages of development
similar to those of the Conifera are gone through in these plants, but are
entirely obliterated at an early period.

THE HIGHER CRYPTOGAMIA. 407

takes place in length, breadth, and thickness. With the
commencement of the cold season the walls of the endo-
sperm which fills the embryo-sac become much thick-
ened, and exhibit lamination of the gelatinous substance of
the thickened portions (PL LIX, fig. 13). If delicate
sections of the endosperm are placed in water, the gela-
tinous matter of the thickening layers of the cell-walls
becomes rapidly and easily dispersed in the fluid ; the pri-
mordial utricles of the cells then lie free in the cell-cavity
(PI. LIX, fig. 17). The thickened walls of the central
cells of the endosperm are the most sensitive to the action
of water. This peculiar nature of the cells of the transitory
endosperm of the first year renders the observation of their
walls especially difficult.*

At the beginning of March the dissolution of the
thickened cell-walls of the endosperm commences. Each
of the primordial cells thus made free exhibits a large
central spherical nucleus filled with brighter fluid (PI. LX,
fig. 1). About April this nucleus is dissolved; cells
whose nuclei have been just absorbed contain 'numerous
spherical drops of a highly refractive substance, which
nearly fill the cell. Further developed cells contain two
(PI. LX, fig. 1*), others four, many only three nuclei.
Around each such nucleus a free daughter-cell is formed,
originally of a spherical shape, lying free in the mother-cell.
By absorption of the wall of the mother-cell the daughter-
cells become free ; the same process is repeated in their
interior (PL LX, fig. 3). Thus the number of the cells
enclosed by the embryo sac increases very rapidly in geome-
trical progression. The embryo-sac itself grows in a re-
markable manner to more than twenty times its previous
volume by pushing aside the loosened cells of the adjoining
portions of the nucleus of the ovule ; its wall, hitherto very
tender, becomes thick and glassy, and ultimately granulated
on the outer surface. At the same time a very active mul-

* The earlier observers considered the embryo-sac filled with cellular tissue
to be a cavity in the tissue of the nucleus (Hartig, < Naturgeschichte der Forst-
culturpflauzen,' see the explanation to fig. 17 of Plate xxv. Gottsche, JJot.
Zeit.,' 1845, p. 380). Quite lately Pineau pointed out its true nature (' Ann. d.
Sc. Nat.,' iii ser. vol. ii, p. 85).

408 HOFMEISTER, ON

triplication recommences in the cells of the ovule, with the
exception of the upper portion of it which has been tra-
versed by the pollen-tnbes and which remains stationary ;
the ovule grows from one third of a line to two lines and
a half.

In the middle of May a simple layer of cells begins to
spread itself on the inner wall of the embryo-sac (PI. LX,
fig. 2). The side-walls of these cells do not yet touch one
another at all points (PL LX, fig. 2b) ; if the embryo-sac is
ruptured by gradually increased pressure, the cells within
it and those also which are spread over its wall are driven
out through the fissure in the form of spherical vesicles
(PL LX, fig. 3). The firm adhesion inter se of the above
cells does not take place until after several layers of them
have been formed (PL LX, fig. 4). The cell-multiplication
at the same time goes on continually, both in the free cells
of the centre, and in those forming the parenchymatal
mass of the periphery. Thus at last there is again formed
an endosperm entirely filling the inner cavity of the
embryo-sac, a body far longer in its circumference and
composed of a far greater number of cells than the one
which existed at the commencement of the winter rest. The
development of the endosperm of Juniperus much re-
sembles that of the species of Pinus whose seeds take two
years to ripen. In the lower part of the nucleus before
the shedding of the pollen there is found a cell surrounded
by concentrical layers of smaller cells: this cell is the
embryo-sac. It becomes filled with a few cells (PL LXIV,
fig. 5), shortly after those pollen-grains which have reached
the nucleus have begun to emit tubes. In this condition
the ovule remains through the first summer and winter.
At the commencement of the next vegetative period the
ovule and embryo- sac increase rapidly and remarkably in
size, and the primordial utricles of the cells which fill the
embryo-sac become individualised. By active multiplication
of these primordial cells, numerous cells are produced
floating freely in the fluid contents of the embryo-sac. They
soon * clothe the inner wall of the embryo-sac in the form
of a compound cellular layer (PL LXIV, fig. 6); by division

* At the beginning of May in the second year.

THE HIGHER CRYPTOGAMIA. 409

of the cells of the latter, coupled with the deposition of new
cellular layers on the inner side of those first formed, the
embryo-sac is soon (within the space of a week) filled for
the second time with closed cellular tissue.

The development of the endosperm of Taxus is far
more simple. The rudiments of the embryo-sacs are here
represented (as has been already mentioned) by several
larger cells situated in the middle of the lower portion of
the nucleus of the ovule, surrounded by cellular tissue
arranged in scale-like layers (PI. LXIII, fig. 2). Soon after
the shedding of the pollen the tissue surrounding those
cells becomes loosened (PI. LXIII, fig. 4). The growing
embryo-sacs begin to increase considerably in size ; this
increase in many instances continues to go on in one only
of the embryo- sacs ; the growth of the others is arrested,
they become shrivelled, and at last, like the loosened cells
of the surrounding tissue, they are dissolved and displaced
by the one embryo-sac (PL LXIII, figs. 5 — 8). Often
however two of these larger cells grow and form embryo-
sacs. The nucleus of the cell destined to form the embryo-
sac is soon absorbed, and the cell then usually assumes the
shape of a flask (PI. LXIII, fig. 5). Two new nuclei soon
appear contemporaneously in its upper part, embedded in
the mucilaginous layer which clothes the inner wall. More
and more nuclei soon make their appearance in the lower
part also of the young embryo-sac in a similar position
(PI. LXIII, figs. 6, 7). At first they often have no nucleoli,
but at a more advanced period of growth the latter are
never wanting. A cell is formed around each of the nuclei
which are deposited upon the inner Avail of the embryo-sac
(PI. LXIII, fig. 8). The walls of the young cells soon close
upon one another, and thus the embryo-sac is filled with
closed cellular tissue, except at its young upper end, where
nuclei are found which for a long time continue to float
freely (PI. LXIII, fig. 9), until at last, at this end also, the
formation of parenchyma proceeds. In those Abietinese
whose seeds ripen the first year, the embryo-sac is filled, a
few days after the shedding of the pollen, with a closed
tissue of large cells (PL LXII, fig. 11), by whose con-
tinual multiplication in all three directions the endosperm

410 HOFMEISTER, ON

increases in size. Thuja and Cupressus behave in just the
same manner.

In all the Coniferae, after the embryo-sac has become
entirely filled with cellular tissue, a considerable growth
commences in certain cells situated close under the mi-
cropylar end of the endosperm, which growth sets in
even long before the cell-multiplication in the neighbouring
cells has ceased (PI. LX, figs. 5 — 7). Thus the essential
part — viz., the large spherical cell — of the so-called cor-
puscula is differentiated from the surrounding tissue. In the
Abietineae each corpusculum is separated from the next by
at least one, often by several cellular layers (PI. LX, figs. 6, 7 ;
PL LXII, fig. 3). The corpuscula of Juniperus (PL LXV,
figs. 1 — 3, 9), Thuja and Cupressus, immediately adjoin
one another. In Taxus two corpuscula are sometimes in
contact ; most of them are separated from one another by
thick layers of cellular tissue (PL LXIV, figs. 1, 2).

The corpuscula of Taxus are shortly ellipsoidal, those of
the Abietineae are ellipsoidal and elongated ; those of Juni-
perus and Cupressus are long and prismatic, with blunt
edges and small ends. The formation of corpuscula is not
always limited to the micropylar end of the albuminous
body. In Juniperus especially, numerous irregularities
occur : sometimes there is only a remarkable increase in
size of the deeply seated cells of the endosperm, some-
times a corpusculum is formed complete in all its parts and
opening in the middle of one of the lateral surfaces of the
endosperm.

The apex of each corpusculum is at first only separated
by a single cell from the inner wall of the upper arch of the
embryo-sac. In most of the Coniferae this cell divides twice,
and produces four cells lying in one plane which are distin-
guished from the neighbouring cells by their contents
being thickly mucilaginous and having many granules ; this
is the case in Pinus sylvestris (PL LX, fig. 8), Pinus Strobus,
austriaca, maritimus and Mughus ; in Abies Larix and bal-
samea ; in Taxus baccata (PL LXIII, fig. 11), and cana-
densis (PL LXIV, fig. 1) ; in Juniperus sibirica (PL LXV,
figs. 2, 9) and communis; in Cupressus pyramidalis and
Thuja orientalis. In Pinus Fraseri I found the four apical

THE HIGHER CRYPTOGAMIA. 411

cells often divided transversely, so that the rosette consisted
of eight cells lying in two planes. Pinus canadensis and
Picca L. are remarkable exceptions. Here the one cell
which covers the top of the corpuscula does not divide by
longitudinal septa crossing one another, but by repeated
transverse septa (PL LXII, figs. 1, 2). It thus keeps pace
with the multiplication of the cells of the top of the endo-
sperm, which multiplication in the other Abietineae and in
Juniperus continues after the formation of the corpuscula,
whilst in the above species the double pairs of cells which
cover the upper arch of the corpuscula are sunk in depres-
sions of the upper side of the endosperm, over which the
primary membrane of the embryo-sac extends. In Juni-
perus, Thuja, and Cupressus the top cells of all the corpus-
cula, with rare exceptions, are closely crowded together at
the base of a wide depression of the top of the endosperm
(PI. LXV, figs. 2, 9). The upper end of the endosperm of
Pinus exhibits as many funnel-shaped depressions as there
are corpuscula ; each of these short passages leads to a
single corpusculum. In like manner, in Juniperus, Thuja,
and Cupressus, the parenchyma of the endosperm grows
over the covering cells of the corpuscula. At the top of
the endosperm there is found a rather deep depression
whose base is occupied by the closely-crowded four-celled
rosettes of the elongated corpuscula, which latter are in
contact with one another.

The cells of the endosperm which adjoin the corpusculum
on the sides and below, divide repeatedly by septa at right
angles to the surface of the latter. A layer is thus formed
which surrounds the corpusculum, and consists of small
cells filled with granular mucilage. This layer is very
striking in the Abie tinea?.

In Pinus sylvestris and austriaca the number of corpus-
cula is from three to five ; in Abies balsamea and pectinata
usually three ; in Pinus canadensis very regularly four (rarely
five) ; in Taxus baccata and Juniperus from five to eight.

The primary nucleus of the cell which becomes the cor-
pusculum lasts for some time ; in Pinus sylvestris (PI. LX,
figs. 5, 6) until the corpusculum has attained half its full

412 HOFMEISTER, ON

size ; in Jimiperus (PI. LXV, fig. 2) until the full size is
attained. In Pinus it usually lies at the upper end of the
corpusculum — that end which is turned towards the micro-
pyle — rarely at the opposite end ; it is embedded in a muci-
laginous layer, which clothes the inner wall of the organ, and
which in Pinus is thin, and rendered turbid by numerous
granules (PI. LXV, figs. 5, 6), and in Juniperus and Cu-
pressus* firm and transparent ; in the centre of the corpus-
culum there is only a small ellipsoidal cavity filled with
watery fluid. At last the nucleus is dissolved ; in Pinus
syhestris this is often preceded by the formation of a free
spherical cell around this nucleusf (PL LX, fig. 5). At
last it disappears from observation, and at the same time, in
the Abietineae, several vacuoles make their appearance : the
latter are so numerous and so close together in Pinus syhes-
tris and Strobus, that they impart a frothy aspect to the
whole contents of the corpusculum ; in Pinus Larix and
canadensis they are less numerous and of very unequal
size. During the further development of the corpuscula
the number of these vacuoles diminishes. Nuclei and free
nucleolate spherical cells now appear amongst them, the
latter at first being only small and few in number. Their
number however soon increases, whilst that of the vacuoles
diminishes more and more. In Pinus syhestris and Strobus,
and in Abies Larix, the latter disappear entirely before the
arrival of the pollen-tube at the corpusculum, whilst in
Pinus canadensis, Picea Larix, and in Larix, one or two of
the vacuoles in the middle of the corpusculum usually last
until the moment of impregnation. In Pinus canadensis,
Picea Larix, and Larix, the free cells which float in the in-
terior of the corpuscula, i. e., the germinal vesicles, appear
almost all undivided until impregnation (PI. LXII, fig. 1) •
in a few cases only in Pinus canadensis and Larix, indivi-
dual germinal vesicles are found more or less entirely filled

* In the later stages of development of the corpusculum ; in the earlier con-
dition strings of granular mucilage radiate from the nucleus.

f As is the case round the primary nucleus of the embryo-sac of Asphodelus
luteus and Funkia ceerulea. See pp. 10 and 13 of my ' Eutstehung des Embryo
der Phaneroganien.'

THE HIGHER CRYPTOGAMIA. 413

by two, very rarely three or four, endogenous daughter-cells.
In Pinus sylvestris on the other hand very many of the
germinal vesicles, and in Pinus Slrobus almost all of them,
contain, even before impregnation, several — sometimes as
many as six, usually four — nucleolate daughter-cells. The
membranes of the germinal vesicles, as well as those
of the daughter-cells formed before their impregnation,
dissolve in water. The germinal vesicles of Pinus cana-
densis contain small amyloid granules which are not found
in other species. The phenomena which may be ob-
served in the formation of the germinal vesicles, resemble
generally those which appear in the formation of the cells
of the endosperm of phsenogams in the restricted sense
of the word. The free cell- formation in the impregnated
embryo-sac of the Iridese* offers the most points of
resemblance. As in that case the first organized forma-
tions have the form of vesicles of moderate size. They
either possess fluid contents only, or in more rare instances
they have one or two spherical bodies (nucleoli) of a
strongly refractive substance, floating in the fluid contents.
These formations according to current notions • must be
considered as nuclei. The larger of these vesicles exhibit
in their interior a small spherical, cellular formation — the
nucleus around which the cell originated — situated some-
what excentrically, and exactly similar to the above-men-
tioned freely -floating bodies. There is only one circum-
stance which does not entirely accord with these explana-
tions of the observations, and that is, that sometimes
(although not often), cells are found whose single nucleus
is decidedly smaller than any one of the freely-floating
nuclei observed contemporaneously in the same corpus-
culmn. This may however very probably depend upon
individual peculiarities. It may well be, that the moment
at which a cell is formed round a nucleus, is determined
by circumstances quite unconnected with the fact whether
or not the nucleus has attained its greatest size. A
nucleus might, long before it was full-grown, become the
middle point of a cell in process of formation. If it be

* « Entstelmng des Embryo,' p. 27.

414 HOFMEISTER, ON

assumed that its growth then ceased, the above pheno-
menon would be sufficiently explained.*

The refractive power of the substance of the nuclei of
the freely-floating cells of the corpuscula of Pinus si/Ivestris,
austriaca, and Strobus, is so exactly the same as that of
the contents of the cells, that the nuclei do not become
visible until by the prolonged action of water, or of tincture
of iodine, the contents of the cell and of the nucleus
are changed, and the albuminous matter coagulated. In
the corpuscula of Pinus canadensis the refractive power of
the nuclei upon transmitted light is greater than that of the
contents of the cells.

The number of the freely-floating cells in the corpuscula
of the Abietineae is so great that they quite fill the latter.
This is the ground of the statement made by Mirbel and
Spach that the corpuscula are filled " par un tissu fin et
jaunatre." In Taxus, Juniperus, and Cupressus, the
number of these cells is usually less, but yet cases occur
here also in which they entirely fill the corpuscula (PI.
LXIII, fig. 11 •; PI. LXIV, fig. 1 ; PI. LXV, fig. 9).

Of the many delicate-walled daughter-cells of the
corpusculum, those which occupy its upper and lower
end often appear to be pressed against it, in like
manner as the germinal vesicles of the phaenogams and
the cells antipodal to them press against the two ends of
the embryo-sac. In the upper end of the corpusculum
they are only found when the arch of the latter is particu-
larly steep, and then several usually occur (PI. LXI,
fig. 1) ; in the lowrer end one only is found, and that not
often ; when present it is much flattened above.

The development of the endosperm in the embryo-sac of
the Coniferse does not appear to be absolutely dependent
upon the contact with pollen of the same species, although

* It is undeniable that many cases of free cell-formation, especially those
occurring in the embryo-sac of phsenogams, when considered by themselves,
agree better with the theory of the identity of tlie cell and the nucleus, than
with the opposite one propounded by Schleiden. It is not so however with all;
in some eases (Asphodelus alius, Staphyleaphmata) the diameters of the cells in
process of formation are always at least half as large again as those of the largest
of the freely-floating nuclei. The undoubted analogy however with the fully-
observed cases of the so-called cell-division, suggests the necessary explanation
even of those more obscure phenomena.

THE HIGHER CRYPTOGAMIA. 415

it is undeniably favoured by such contact. I have known
flowers of female specimens of Juniperus sibirica, which
had been completely separated from male ones, to produce
normal fruit, and to develope endosperm with fully formed
corpuscula. Female flowers of young trees of Pinus cana-
densis, which were three miles distant in a straight line
from the nearest other trees of the same species, produced,
for two years successively, only female flowers, but no male
ones. Microscopical examination showed that in both cases
no pollen-grains were present upon the nucleus. In both,
the formation of embryos was entirely suppressed.

After the interval which occurs in the growth of the
pollen-tubes — and which takes place even in those Coniferse
whose seeds ripen the first year — the latter begin again to
penetrate towards the embryo-sac. This happens almost
at the time when the differentiation of the corpuscula from
the surrounding tissue commences. After the tubes are
completely formed they reach the endosperm : in Pinus
sylvestris and Juniperus sibirica this happens at the be-
ginning of June, in Pinus Strobus and Juniperus communis
at the end of June of the second year ; in Abies excelsa and
Taxus canadensis in the middle of May, in Taxus baccata
at the end of May, and in Pinus canadensis at the end of
June, of the first year. The deeper the pollen-grains pene-
trate into the nucleus the thicker they become, a pheno-
menon which is most manifest in Taxus, and least so in the
Abietineae. The growth in thickness of the lower part of
the pollen-tube of Taxus is so remarkable, that the organ
assumes the form of a conical sac (PI. LXIII, fig. 11;
PL LXIV, figs. 1, 2). The great transverse increase does
not commence until the completion of the longitudinal
growth.

About the time when the pollen-tube reaches the endo-
sperm, the very thick, hitherto leathery and tough primary
wall of the embryo-sac which encloses the endosperm, is
softened at the top. The pollen-tube breaks through this
wall, apparently after some resistance, (a constriction or
sudden narrowing of the tube is often visible at this place),
and reaches the double pairs of cells which cover the tops
of the corpuscula. Sometimes it makes its way sideways to
the corpusculum, piercing through and destroying the

416 HOFMEISTER, ON

tissue of the endosperm. This has been often observed in
Pinus canadensis. In Taxus it often destroys the entire
uppermost part of the endosperm ; on the other hand the
four cells which close up the corpusculum which is about
to be impregnated, are at first only slightly pushed apart
from one another, by the protrusion by the pollen-tube of
a short prolongation which passes between their detached
edges and up to the outer wall of the corpusculum (PL
LXIV, figs. 1,2). These cells do not disappear until a later
period, after the formation of the pro-embryo ; they often last
for a very long time (PL LXIII, fig. 13). Juniperus and
Thuja (PL LXV, figs. 2, 3, 9, 10,) behave in a similar
manner. In the Abietinese, on the other hand, the cells above
the corpuscula are destroyed immediately after the pollen-
tube has reached them (PL LX, fig. 9 ; PL LXI, fig. 1 ;
PL LXII, figs. 2, 3). Its end attaches itself to the outer
wall of the corpusculum ; in Pinus canadensis it then
often expands considerably in breadth (PL LXII, fig. 3).
With this process in most cases, its penetration terminates ;
more rarely it breaks through the wall of the corpusculum
and grows into it for a short distance. This happens
regularly in Pinus Larix, and tolerably frequently in Pinus
canadensis (PI. LXI, figs. 13, 14 ; PL LXII, fig. 2).*

Free spherical cells are often developed in the interior of
the ends of those pollen-tubes of the Coniferae which
penetrate up to, or into the corpusculum. In the Abietineae
the observation of them is often rendered difficult by the
large number of co-existent starch-granules, but even here
undoubted instances of the presence of cellular formations
in the pollen-tubes may easily be seen. The pollen-tube of
Pinus canadensis when it has penetrated into the corpus-
culum usually contains — -in addition to granules of starch
and mucilage — several (2, 4, or even 8) sharply defined
spherical balls of finely granular protoplasm floating freely
in the interior of the tube (PL LXIII, fig. 2). In some of
these corpuscula I saw, close under the end of the pollen-
tube but not in contact with it, a free oval cell differing
from the germinal vesicles which — still in the same state as-
before the arrival of the pollen-tube — filled the rest of the

* Many such cases are figured by Pineau, 'Ann. d. Sc.' iii. ser., vol. xi,
pi. vi, fig. .4 ; and by Schacht, ' Entw. des Pflanzen-embryon,' pi. xi, fig. 5 — 7.

THE HIGHER CRYPTOGAMIA. 417

cavity of the corpusculum, by being somewhat larger, and
especially by its containing a considerable quantity of
granules of protoplasm of a larger size (PI. LXII, fig. 2).
The nucleus of these cells differs from those of the neigh-
bouring germinal vesicles by the more considerable size of
the nucleoli. In other corpuscula which were taken partly
from ovules of the same cone I found a similar cell,
but without a nucleus, at the base of the corpusculum. In
other corpuscula, again, from the same inflorescence, a cell
of the same kind furnished with a firm membrane * was
firmly pressed into the lower end of the corpusculum. It
can now be recognised beyond a doubt as the primary cell
of the compound pro-embryo (PI. LXII, fig. 4). In an
impregnated corpusculum of Pinus canadensis which
already contained a multicellular pro-embryo, I once saw a
large free cell, situated above the latter and containing two
nuclei, and very similar to an impregnated germinal vesicle
on the point of dividing (PL LXII, fig. 5). This observa-
tion is the only one of the kind which occurred in the
course of my very numerous investigations, and it indicates
that more than one germinal vesicle of the same corpus-
culum may be impregnated.

The pollen-tube of Pinus sylvestris, after penetrating the
rosette of the corpusculum, usually passes only for a short
distance into the interior of the latter, so that the end of
the tube projects into the end of the cavity in a hemi-
spherical form ; a farther penetration is of rare occurrence.
In the earliest observed conditions in which a change in the
contents of the corpusculum was perceptible, an oval, capa-
cious, sharply defined cell, was visible near the base of the
corpusculum ; in the more pointed lower end of this cell a
lenticular nucleus was embedded in a considerable accumu-
lation of granular protoplasm (PI. LX, fig. 9). The walls
of the upper part of the cell are clothed with a thin layer
of plasma ; a flattened layer of protoplasm passes through
the entire length of the upper cavity of the cell. In other
corpuscula the lower end of this cell almost touched the
base of the corpusculum. In these cases the nucleus, and
the accumulation of protoplasm enclosing it, appeared sur-

* In the conditions previously mentioned this membrane was wanting.

27

418 HOFMEISTER, ON

rounded by a firm cell-wall, and separated from the ripper,
very delicate-walled, larger un-nucleated portion of the cell.
Corpuscula from the same tree examined one or two days
later, exhibited this small lower daughter-cell attached to
the lower part of the corpusculum, to whose walls the
lateral surfaces also of the upper, un-nucleated, larger
portion of the cell adhere, whilst the boundary in the
direction of the apex of the corpusculum becomes in-
distinct (PL LX, fig. 10). As in Pinus canadensis the end
of the pollen-tube during these processes exhibits no
opening ; its contents are of the same nature as in the
species just mentioned. The unimpregnated germinal vesi-
cles which fill the cavity of the corpusculum remain at
first unaltered, which is also in accordance with Pinus
canadensis. A difference, however, exists in Pinus sylvestris,
viz., that very often one or two of the germinal vesicles
which lie in the micropylar end of the corpusculum and
touch the end of the pollen-tube, have firm membranes
composed of cellulose, a fact which has never been observed
in Pinus canadensis. After the cell which is pressed into
the lower end of the corpusculum has become changed by
repeated divisions into the compound pro-embryo, the tip
of the pollen-tube of Pinus sylvestris often appears to be
open, and its contents to be discharged into the cavity of
the corpusculum ; this is plainly the result of mechanical
rupture. The cells of the endosperm which surround the
funnel-shaped depression leading to the corpusculum
expand considerably in width after impregnation, and
compress the pollen-tube, frequently to such an extent as
to obliterate the cavitv of the latter. Its contents thus
undergo a strong pressure, which must ultimately lead to
the rupture of the free end.

In Pinus abies, L. [Abies excelsa, D. C), I observed
phenomena similar to those in Pinus sylvestris. In
some cases I saw the daughter-cell of the corpusculum
— after the former had grown to a large size, and its
contents had increased and become firmer — in immediate
contact with the end of the pollen-tube (PI. LXI, fig. 1).
In others I found a similar but very large cell half way
towards the base of the corpusculum divided into four

THE HIGHER CUYPTOGAMIA. 419

cells, forming two larger upper ones and two smaller termi-
nal cells (PI. LX, figs. 2, 24.) The identity of this cellular
body with the compound pro-embryo which is afterwards
firmly inserted into the lower part of the corpusculum is
beyond all doubt. In Pinus Abies the germinal vesicles,
which remain in contact with the end of the pollen-tube,
regularly become clothed with firm elastic cell-membranes.

The pollen-tube of Pinus Larix usually swells out in a
vesicular manner within the funnel-shaped depression of
the endosperm above the corpusculum, and then sends
forth a pointed prolongation, which pierces through the
covering cells of the latter. The membrane of the tube is
incomparably more tenacious than in the above-mentioned
species. In the latter when the endosperm is detached
from the nucleus the pollen-tube regularly tears off at the
place where it emerges from the tissues of the nucleus,
whilst in Pinus Larix the apex of the pollen-tube may often
be drawn out from the corpusculum, so as to hang freely
down for a considerable distance.

The end of the pollen-tube even before it reaches the
corpusculum exhibits an accumulation of protoplasm which
is often sharply defined like a cell, and further upwards in
its interior numerous starch-granules are seen partly com-
bined in groups of twos or fours. Immediately after reach-
ing the corpusculum the apex of the pollen-tube, when
drawn out from the latter, appears rather thin-walled and
without appendages. In cones somewhat more developed
a cell is found fastened to the end of the pollen-tube when
the latter is detached. The diameter of this cell seldom
equals that of the end of the pollen-tube, and often re-
mains considerably less. It resembles in all its parts one
of the smaller germinal vesicles which float in the interior
of the corpusculum. Like these vesicles it exhibits a
nucleus of lighter substance, and is devoid of the firm cell-
membrane.* No further change is at this time perceptible
in the remaining portion of the corpusculum.

* At the place where this cell is attached, the pollen-tube exhibits no trace
of an opening, and there is nothing to show that the cell, which differs so
remarkably from the pollen-tube by the absence of a firm membrane, has grown
out of the latter.

420 HOFMEISTER, ON

In corpuscula which are about two days more advanced a
larger cell is seen near the end of the pollen-tube which now
reaches down into the corpusculum ; this larger cell differs
from the neighbouring unaltered germinal vesicles in its
circumference — which is more than double that of the latter
■ — in its more transparent fluid contents, and in its firmer
membrane. Its upper end not unfrequently protrudes
above the spot at which the before-mentioned small cell is
attached to the apex of the pollen-tube. The large free cell
never exhibited any connexion with the small cell. In other
corpuscula of the same cone a larger cell of the same kind
occurs at the base of the corpusculum. Its circumference
is more considerable, and its contents of the same kind, as
in the above-described impregnated germinal vesicles of
Pinus sylvestris. The more pointed lower end of the oval
cell is filled by an oval daughter-cell with turbid contents
and a firmer membrane. The larger upper part of the cell
is devoid of a nucleus ; a thin protoplasmic layer covers
the inner wall, and a similar flattened layer traverses the
inner cavity longitudinally (PI. LXI, fig. 13). A short
time afterwards the lowTer cell, which is rich in granular
protoplasm, appears pressed into the base of the corpuscu-
lum (PL LXI, fig. 14). It is now drawn out breadthwise;
its upper wrall, which is turned towards the inner cavity of
the corpusculum, is only slightly arched. Observation
shows that it is the rudimentary cell of the compound pro-
embryo. The upper unnucleated portion of the large cell
becomes attached laterally to the arch of the corpusculum,
but is soon dissolved.

The free germinal vesicles in the upper part of the cor-
pusculum continue in the mean time without any observable
alteration (PL LXI, fig. 14). On the other hand, the cell
attached to the tip of the pollen-tube becomes clothed with
a firmer membrane of cellulose at the time when the large
transparent cell appears near the tip of the pollen-tube ;
sometimes also it increases in size so that its transverse
diameter becomes three times that of the pollen-tube
(PL LXI, figs. 12—14). The inner wall of the pollen-
tube exhibits, exactly at the point where the cell is attached
to it, a narrow pit traversing the thickening layers which

THE HTGHER CRYPTOGAMIA. 421

in the mean time have been deposited upon its wall (PI. LXT,
fig. 12). This pit always appeared to be closed on the out-
side by the primary membrane of the pollen-tube ; no open
communication between the pollen-tube and the cell could
be ascertained. The nucleus of this cell has by this time
disappeared ; its contents, which are tolerably transparent,
are only rendered turbid to a certain extent by a few fine
granules. Sometimes it contains some larger bodies, equal
in size to the starch granules in the pollen-tube, and com-
posed of a substance rendered brown by iodine. The
relations of position between the cell and the pollen -tube
are of two kinds : either the upper part of the cell is
attached to the terminal point of the extended conical tip
of the pollen-tube, and thus hangs down freely into the
cavity of the corpusculum (PI. LXI, figs. 13, 14), or else
the end of the pollen-tube is lifted up round the cell — so
as to form an annular cushion — and grows round the larger
part of the cell so as only to leave the hemispherical lower
end protruding out of the introverted end of the pollen-
tube (PL LXI, fig. 11). This process has been observed
in its different stages. If a moderate pressure is applied to
the upper end of a pollen-tube having the attached cell
enclosed in the introversion of its apex (PI. LXI, fig. 1 1),
the introverted membrane often becomes exserted, and the
exserted portion then appears to be conical, and bears the
cell in question at its outermost tip (PI. LXI, fig. 11), just
as in the first case above described. The two forms of the
end of the pollen -tube are equally common in longitudinal
sections of corpuscula. In isolated instances two such cells
are attached to the tip of the pollen-tube.

From these observations on the Abietinese I think the
following conclusions may be drawn as to the development
of the embryo. After the arrival of the end of the pollen-
tube at or into the upper end of the corpusculum, one of
the germinal vesicles lying near the end of the pollen-tube
is impregnated. It increases in size, and glides through the
mass — consisting of protoplasm and unimpregnated germi-
nal vesicles — which fills the corpusculum, clown to the base
of the latter, into which it presses itself. At this time (in
Finns canadensis) or, (in P. sylvestris and Lariat) even

422 HOEMEISTER, ON

during its downward progress, a daughter-cell is formed in
its lower end, by the repeated bipartition of which, the
compound pro-embiyo originates. It always happens in
Pinus Larix, and frequently in P. sylvestris, that one or
more of the germinal vesicles which are in contact with the
pollen-tube, but which remain unimpregnated, acquire firm
membranes of cellulose, and attach themselves to the tube,
but this phenomenon is not essentially connected with im-
pregnation.*

The swelling which the pollen -tube of Tawus baccata
forms above the top of the endosperm often attains di-
mensions equalling that of the latter. Where much pollen
has fallen, several pollen-tubes almost always penetrate into
the ovules. These tubes swell and press against one another,
so that they not only fill the entire cavity above the en-
dosperm, but pass beyond it, sending forth prolongations
of different forms. Cases occur in which the swollen ends
of numerous pollen-tubes grow round the endosperm on
all sides, and meet underneath it, thus smothering it by
cutting off the access of nutriment. Even before the cor-
puscules are fully developed one, or more rarely two, large
spherical cells are formed in each pollen-tube. These cells
have no firm membranes, and are filled with a thickly-
fluid finely- granular protoplasm which encloses a central
nucleus. These cells at first float quite freely in the in-
terior of the pollen-tube. They are often surrounded by a

* Sclmclit ('Beitrage zur Anatomie,' &c, Berlin, 1854, p. 287, cDas Mikro-
skop,' 2nd edit., Berlin, 1855, p. 151, ' Flora,' 1S55) arrived at a conclusion to
some extent in accordance with the above, inasmuch as it assumed the descent
of the rudiment of the pro-embryo from the upper end of the corpusculum to
the lower. In the 'Flora' for 1855 I have attempted to show that Schacht's
conclusions are incorrect. The objects which he took for the rudiments of the
pro-embryo cannot in the nature of things be what he supposed.

Geleznoff 's statements as to the formation of the embryo of Larix are more
opposed to mine. He considers that the cell attached to the pollen-tube grows
by degrees out of the apex of the latter, and he assumes that the two communi-
cate by an open pore, and that the first cell of the pro-embryo originates in the
lower end of this cell. In all these points my observations gave a negative
result. I believe that I may place great reliance upon them, not only on account
of my investigations having been carried on for three years, but because my
numerous observations were repeated and verified during a sojourn in the Alps,
where, from the opportunities which existed for collecting cones at places of
different altitudes, the various stages could be followed out much more easily
and with greater certainty than could be done in a flat country.

THE HIGHER CRYPTOGAMIA. 423

thin layer of granular mucilage, from which fine strings
radiate to the Avails of the tube. In more advanced ovules
these cells appear to be situated nearer to the lower wall
of the pollen-tube, and to be fastened to the latter by an
accumulation of viscid protoplasm ; their earlier spherical
form has passed into a flatly-ellipsoidal one. Instead of
the central nucleus, which has now disappeared, two newly-
formed nuclei make their appearance, one in each focus of
the cell (PI. LXIII, fig. 11).

The unimpregnated corpuscula usually contain only a
few (from six to ten) free germinal vesicles, amongst which
one in particular, which floats in the middle part of the
corpusculum is distinguished by its size, by the sharpness
of its outline, and by the richness of its granular contents
(PL LXIII, fig. 11)*

The prolongation of the pollen-tube which penetrates
between the cells of the rosette of the corpusculum is fre-
quently, but not always, filled by four cells placed cross-
wise, manifestly produced by the twice-repeated division by
means of longitudinal septa of the (originally) free spheri-
cal cell which is now adherent to the inner wall of the
tube (PI. XLIV, fig. 2). One of the germinal vesicles in
the interior of the corpusculum, apparently the central one,
now appears swrollen, as well as more rich in granular
contents, and in many instances situated nearer to the base
of the corpusculum (PL LXIV, fig. 2). The membrane of
the pollen-tube when uninjured appears completely closed.
The openings which are sometimes seen in it after its
separation from the corpusculum are almost certainly acci-
dental ruptures. The contents of the four cells which fill
the pollen-tube, or of the one cell which is sometimes
found there, consist of very small motionless bodies, partly
spherical and partly spindle-shaped, which fill the cell in
great numbers. The next condition of the impregnated
corpuscula exhibits the impregnated germinal vesicle at the
base of the latter, firmly pressed into the lower end of the

* In the ' Vergl. Unters.,' p. 129, I took this formation to be the primary
nucleus of the corpusculum. This I think was an error, because in the Abie-
tinefe and Juniperiuese the nucleus of the corpusculum does not last until im-
pregnation.

424 HOFMEISTER, ON

corpusculura (PI. LXIV, fig. 1). The unimpregnated
germinal vesieles remain still unchanged in the upper
part of the corpusculum.* Sometimes one or two of the
impregnated germinal vesicles which are in contact with
the pollen-tube become clothed with firm cellulose mem-
branes, and adhere to the apex of the tube.

The side-walls of the upper end of the corpuscula of
Thuja orientalis, Juniperus communis, and /. sabina are
considerably thickened, and furnished with delicate an-
nular ridges, which are often very clearly visible in the
form of transverse stripes. At the beginning of July the
contents of the corpuscula consist, as has been mentioned,
of very finely granular almost glass-like transparent pro-
toplasm in the middle of which a large vacuole occurs.
Above this vacuole the primary spherical nucleus of the
corpusculura lies embedded in the protoplasm. This nu-
cleus afterwards disappears, and in its place some new free
nuclei make their appearance, around which, in a short
time, spherical cells are formed, which are the germinal
vesicles. Whilst the latter continue to grow, the central
vacuole becomes perpetually smaller and smaller : at last
it disappears altogether, and the corpusculum is filled with
a uniform mass of protoplasm having the germinal vesi-
cles floating in it. Amongst the latter, one or more near
the upper end of the corpusculum are distinguished by
their great size (PL LXV, fig. 9 on the right).

The pollen-tube breaks through the softened membrane
of the embryo-sac — which membrane extends over the
depression at the top of the endosperm — and becomes
swollen so as to entirely fill the depression. In the regular
course of things a large spherical cell now appears in the
interior of the pollen-tube, filled with granular mucilage
which surrounds a central transparent nucleus (PI. LXV,
fig. 9). In certain conditions which must doubtless be
looked upon as more advanced, this cell has the form
of an ellipsoid, and is furnished with two nuclei, one in
each focus ; other conditions again exhibit the cavity of
the cell traversed by a septum passing between the two

* A decisive proof that the pollen-tube does not, as Schacht supposes, en-
tirely fill the corpusculum ('Flora,' 1S55).

THE HIGHER CRYPTOGAMIA. 425

nuclei. Ultimately, and shortly before the pollen-tubes
penetrate into the rosettes of the corpuscula, two spherical
cells of the kind above mentioned (PI. LXV, fig. 9 on the
left) are often found in the tube, which in all probability
are produced by the division of the original single cell.
The increasing pollen-tube now presses together the ro-
settes of the corpuscula, and sends a short, very delicate-
walled prolongation through the line of contact of the four
cells which are in process of dissolution, into each corpus-
culum which is to be impregnated (PI. LXV, figs. 3, 10).
In some cases the free cells contained in the pollen-tube
now appear to be much flattened, attached to the wall of
the tube, and divided into a larger number, normally six-
teen, of small cells lying in one plane (PI. LXV, fig. 4) ;
in other cases the pollen -tube contains four middle-sized,
or eight smaller, roundish cells, without any firm mem-
brane (PI. LXIV, fig. 3), and which probably have arisen
from repeated division of one of the large originally spheri-
cal cells. The protruded portion of the pollen-tube breaks
through the compact membrane of the upper end of the
corpusculum, forming a fissure which is very visible in the
apical aspect of the latter. Even after impregnation, the
ends of the tubes if carefully extracted appear quite
closed (PI. LXV, fig. 10). In an object so delicate as the
membranes of these tubes, a small opening might easily be
overlooked. The following observation, however, is de-
cisive as to the non-existence of any such opening : the
contents of the corpuscula, especially of those of Juni-
jperus sabina and communis, when just impregnated, swell
up after imbibing water, and rupture the wall of the cor-
pusculum. If a longitudinal section of the endosperm of a
germinal vesicle which has just been impregnated, is
placed under the microscope, it will be seen that as the
contents of the corpusculum swell, the delicate-walled pro-
longation of the pollen-tube which reaches into the upper
end of the corpusculum is intersected and ultimately
ruptured, whereupon an active current begins to flow out
of the corpusculum into the pollen-tube. Frequently, but not
always, one of the round cells in the pollen-tube forces its way
into the prolongation which is sent out by the membrane

426 HOFMEISTER, ON

of the latter into the corpusculura which is to be impreg-
nated. These cells, which now become very easily dis-
integrated, contain numerous spindle-shaped motionless
bodies, consisting of a substance coloured brown by iodine.
These bodies are short in Thuja and elongated in Juniperus
(PI. LXIV, fig. 3J).*

The first change which is visible in the corpusculum after
the entry of the pollen-tube, is an increase in the granular
matter contained in the larger germinal vesicle. This cell
gradually moves towards the lower end of the corpusculum,
against which it ultimately presses itself (PL LXV, fig. 10).
The larger germinal vesicles which lie in its way are dis-
placed and dissolved ; the smaller ones remain unaffected.
Since any successful longitudinal section through the
endosperm of an impregnated germinal vesicle lays bare
many different stages of development of neighbouring
corpuscula, there cannot, in the great number of cases
which are brought into comparison, be any doubt as to the
order of their succession. Even in Juniperus, especially in
Juniperus communis, the smaller impregnated germinal
vesicles which are immediately attached to the end of the
pollen -tube, very often possess firm membranes composed
of cellulose.

In all the Coniferge the impregnated germinal vesicle,
which is pressed into the bottom part of the corpus-
culum, divides by a transverse septum, so far that is as
this division has not already taken place during its descent.
The two daughter-cells — of which the upper is the larger
one and the lower more rich in protoplasm — divide by lon-
gitudinal septa : in some cases this division occurs only in
the lower one (PL LX, fig. 11 ; PL LXI, figs. 3—7). Shortly
afterwards the septum which divides the upper, more empty
cell or cells, from the rest of the cavity of the corpusculum,
is dissolved. The two longitudinal portions of the lower
daughter-cell of the germinal vesicle form the first rudiment
of the pro-embryo of the Coniferse. Its formation is always

* It might easily be imagined that the cellules produced in the interior of
the ends of the pollen-tube of Coniferae might produce spermatozoa. My obser-
vations however have hitherto only yielded negative replies to the question, as
will be seen by the account given above.

THE HIGHER CRYPTOGAMIA. 427

the same, even in species which differ widely as to the
period of development.

In the Abietineae both the cells — whose form is that of
the longitudinal moieties of a blunt cone, with a convex
basal surface — either divide again immediately by longi-
tudinal septa at right-angles to the one last formed (PL LX,
figs. 11, 12 ; PI. LXI, fig. 3), or else a division first occurs
in each of them by transverse septa perpendicular to the
longitudinal axis of the corpusculum, by which the cells are
divided into two very unequal portions, the upper one being
much the largest. In the lower, smaller ones of the newly-
formed cells, which contain much more concentrated mu-
cilage than the upper ones, the division by longitudinal septa
then ensues, which latter septa are perpendicular to the
septum dividing the two cells (PI. LXI, fig. 6). The latter
phenomenon is the most common.

The pro-embryo now consists of two pairs of two-celled,
parallel rows of cells, having their edges of contact rect-
angular. The number of its cells is increased by repeated
division of each of the (lower) terminal cells by means of
septa at right-angles* to the longitudinal axis of the organ.
It is a rule without exception that the lower of the newly-
formed cells are the smallest, but the richest in formative
matter. The pro-embryo up to this time occupies only a
proportionably small space, rilling the lower part (a tenth
to a fifth part) of the corpusculum. As the development
of the pro-embryo has stretched the lower part of the cor-
pusculum downwards whilst its upper part remained sta-
tionary, the portion of the corpusculum which is filled by
the pro-embryo bears a much larger proportion to the
upper part, than the portion occupied by the germinal
vesicle when first impregnated. The pro-embryo exhibits
no upward growth. The lateral walls of its uppermost
oldest cells are as intimately amalgamated with the inner
wall of the corpusculum as the thickening layers of the
same wall are with one another.

* Speaking more accurately we might say, transverse septa radial to the inner
wall of the corpusculum. They are often strongly inclined downwards from the
longitudinal axis of the pro-embryo, and are thus convex upwards (pi. lx, fig. 13 ;
pi. ixi, fig. 16) ; the position at right angles to the axis of the organ is first
assumed by them after the subsequent longitudinal and transverse expansion of
the latter.

428 HOFMEISTER, ON

In the upper part of the corpusculum the numerous
spherical sister-cells of the germinal vesicle are still dis-
tinctly perceptible (PI. LX, fig. 13 ; PL LXII, fig. 5). From
the fact of their presence* it is impossible that the opinions
of Schleiden, Schacht, and Geleznow, as to the process of
embryo-formation in the Coniferae can be correct. Accord-
ing to the two former the pollen- tube penetrates into one
of the corpuscula, fills it up by degrees entirely, and pro-
duces the pro-embryo in its lower end, which is pressed
against the inner surface of the corpusculum. If this were
so, the pollen-tube must pierce through the mass of spheri-
cal cells which fills the cavity of the corpusculum before
impregnation. Nothing however is easier than to see that
those cells are still present when the pro-embryo appears.
They are only dissolved very gradually, and become changed,
together with the rest of the contents of the upper part of
the corpusculum, into a yellowish grumous mass.

The increase in length of the pro-embryo ultimately rup-
tures the base of the corpusculum. A considerable longi-
tudinal expansion immediately takes place in the two pairs of
cells of which it consists ; this expansion usually occurs in the
second cell reckoned from above (PL LXI, fig. 7 ; PL LXII,
fig. 8), but sometimes the first expands also. The lower
end of the pro-embryo is thus driven deeply into the tissue
of the endosperm underneath the corpuscula. The axile
cells of the middle portion of the endosperm become in the
mean time loosened and softened, by which the course of
the continually-descending end of the pro-embryo is pointed
out beforehand. The courses of the continually-elongating
pro-embryos through the pultaceous mass of the softened
cellular tissue, form delicately-winding spirals.

Soon afterwards the longitudinal rows of cells comprising
the pro-embryo become detached from one another. The
separation commences at the lower end and progresses
from thence upwards (PL LXI, figs. 9, 10). During this
breaking up of the pro-embryo into four (very rarely more
than four) simple rows of cells, the four shorter cells which
formed its upper end which was enclosed by the corpus-
culum, become dissolved (PL LXI, figs. 8 — 10).

* Observed by Gottsche (' Bot. Zcit.,' 1844, 509), and by Pineau, ' Arm. d.
Sc. Nat.,' 3rd ser., vol. ii.

THE HIGHER CRYPTOGAMIA. 429

Shortly after the rows of cells of the pro-embryo have
separated from one another, the formation of the embryo
itself commences in the terminal cell of each row, either
immediately, or after the occurrence of divisions by hori-
zontal septa. This formation takes place by the repeated
division of the apical cell for the time being by means of
septa inclined in the first place alternately to the right and
to the left, and soon afterwards in three different directions.
The cells of the second degree divide into inner and outer
cells by radial, and those of the third degree by longitudi-
nal septa parallel to the axis, and so on, following the mode
of cell-multiplication in the terminal bud of Equisetum and
other plants (PI. LXI, fig. 11; PL LXII, figs. 9, 10). In the
half-ripe seed the number of rudimentary embryos is at
least four times as great as that of the corpuscula impreg-
nated. Of these however, in the greater number of cases,
one only is developed rapidly and vigorously ; the rest are
much less fully developed, shrivel up by degrees, and ulti-
mately die. During the formation of the embryo the
younger lower cells of the pro-embryo — which latter has be-
come the suspensor — also expand considerably in length, and
at last the same expansion occurs in its massive portion im-
mediately adjoining the embryo (PL LXI, fig. 10 ; PL LXII,
fig. 10). The latter also then become disconnected from
the laterally-adjoining cells (PL LXII, fig. 10), and often,
especially near the lower end, bear a deceptive resemblance
to a pro-embryo not yet broken up into its longitudinal rows
of cells.*

After the penetration of the pro-embryo into the middle
region of the endorsperm, the walls of the corpusculum can
easily be separated from the surrounding tissue. They
exhibit now prominent reticulate ridges on the outer side,
corresponding in direction with the edges of contact of the
neighbouring cells, and they have also somewhat large flat
pits. These phenomena are especially manifest in Pinus
canadensis (PL LXII, fig. 8). In this species the upper
portion of the four uppermost cells of the pro-embryo are
normally much thickened, and then exhibit manifest
lamination (PL LXII, fig. 7) ; sometimes strange-shaped

* It is doubtless from this phenomenon that some observers, especially
Geleznow, deny the breaking up of the pro-embryo into distinct suspensors.

430 HOFMEISTKR, ON

accumulations of gelatinous matter are found on the outer
walls of these cells (PI. LXII, fig. 8).

I have never seen the pollen-tube ramify in the Abietineae.
Each pollen-grain sends forth only one tube; if several
corpuscula of the same ovule are to be impregnated, it is
indispensable that several pollen-tubes should reach the
nucleus. There is no ground for assuming an incapacity
for impregnation in any of the different corpuscula of the
same endosperm. The impregnation of all the corpuscula
of one endosperm, when not exceeding three in number,
happens not unfrequently m Pinus sylvestris and canadensis,
each being acted upon by a special pollen-tube. In Taxus
the impregnation of several corpuscula by the very widely
expanded end of a single pollen -tube, is of very frequent
occurrence ; and in Juniperus and Thuja it is the rule.

The impregnated germinal vesicle of Taxus baccata
and canadensis divides frequently by longitudinal septa
before any increase takes place in the number of
its cells in a longitudinal direction. The pro-embryo
not unfrequently consists of only four longitudinal rows"
of cells, but usually of six (PI. LXIII, fig. 12). In
the longitudinal development of the pro-embryo its rows
of cells behave very differently. In some, multiplica-
tion and growth cease at a very early period ; it usually
happens that the upper end of the pro-embryo exhibits
some three-sided cells which renew themselves rapidly
downwards, and belong to no one of the longitudinal
rows underneath, of which the pro-embryo is composed.
Very commonly two or one of the longitudinal rows of cells
immediately adjoining the longitudinal axis of the pro-
embryo are more vigorously developed and multiply their
cells in a longitudinal direction more rapidly, than the
cells nearer to the periphery (PI. LXIII, fig. 13). The
pro-embryo does not break up into single rows of cells
until a later period, and then usually only partially. Nor-
mally one only of them goes beyond the first commence-
ment of embryo-formation.*

* ' Hartig zur Entwickelungsgesch. d. Pflanzen,' Leipzig, 1844, fig. 25, and
Schacht (1. c. pi. ix, figs. 11, 13) represent the first stage of development of
the pro-embryo as an oval mass of parencbymatal cellular tissue. I cannot
confirm this ; the pro-embryo appeared to me, even in its earliest youth, to be
always clearly composed of longitudinal rows of cells.

THE HIGHER CRYFTOGAMIA. 431

The impregnated germinal vesicle — which is pressed into
the lower end of the corpuscuhim— of Juniperus communis
and sabina, as well as that of Thuja orietitalis, divides by
a transverse septum into two daughter-cells (PI. LXV, fig.
10), of which the lower one frequently encloses the larger
portion of the protoplasm of the mother-cell. The upper
wall of the upper cell is usually soon dissolved (PL LXI,
fig. 4) ; when it lasts longer (as is often the case) the
same vigorous downward expansion which takes place
after some time in all the cells of the pro-embryo, takes
place also in the uppermost of the two cells of the rudi-
mentary pro-embryo (PI. LXV, fig. 3).* The farther
development of the daughter-cell of the impregnated
germinal vesicle resembles, in its essential features, that
of the Abietineae. It divides by longitudinal septa, and
the elongated daughter-cells divide by transverse septa,
which latter division is repeated in the terminal cells. The
number of longitudinal divisions of the second cell of the
pro-embryo is however far less definite than in the Abietineae.
The most usual number of the rows of cells of the pro-
embryo is four, but pro-embryos are also often found which
consist of only two or— on account of the longitudinal di-
vision of one of the latter — of three longitudinal rows of
cells (PI. LXV, fig. 4).

These rows of cells very soon become disconnected after
the pro-embryo has broken through the base of the corpus-
culum. Their longitudinal expansion is still more re-
markable than in the Abietineae (PL LXV, fig. 5). If
after the last transverse division (PL LXV, fig. 6) of the
terminal cell of one of the detached rows of cells, the for-
mation of the embryo commences by the production of
differently inclined septa in the lower one of the newly-
formed cells, then the lower end of the last cell of the pro-
embryo, upon which the. embryo is seated, grows very

* These enlarged upper portions of the impregnated germinal vesicle exhibit
a very large nucleus with proportionally large nucleoli. The occurrence of the
division of the germinal vesicle into an upper and a lower portion, of which the
latter is destined for more active further development, the former remaining
stationary, and sometimes containing a nucleus, sometimes not— brings to
mind the similar phenomena in Gagea and Fritillaria (' Entstehung des Embryo,'
pp. 20, 21).

432 HOFMEISTER, ON

considerably in breadth (PL LXV, figs. 7, 8). In Juni-
perus also all the numerous young embryos usually mis-
carry, except one.

The stages of development of the embryos of the Co-
niferse which follow next after the impregnation of the
germinal vesicle, are passed through with just as much
rapidity as contemporaneity. A very short time, scarcely
twenty-four hours, elapses between the arrival of the
end of the pollen-tube at the upper end of the corpus-
culum of the Abietinese, and the formation of the four-
celled compound pro-embryo at its base; and these
processes of development occur almost contemporaneously
in all ovules of all trees of the same species growing
under similar circumstances. Thus in J 854 I found
that on the 22nd of June, near Leipzig, no single pollen-
tube of Pinus sylvestris had reached a corpusculum ;
whereas only three days later, on the 25th of June, there
was only one amongst several hundreds of impregnated
corpuscula which I examined, whose impregnated ger-
minal vesicle was not already divided into four cells. In
Taxus and the Juniperineae the contemporaneity of the
development is less complete ; here we find different stages
of development extending over about eight days, consist-
ing of germinal vesicles unimpregnated, impregnated and
unicellular, or impregnated and multicellular, all near one
another.

Robert Brown* was the discoverer of the poly-embryony
of the Coniferse. In a later treatisef (1834) he pointed
out the origin of the pro-embryo in large cells of the en-
dosperm, to which he gave the name of corpuscula. Corda}
first proved that the pollen-tubes penetrate into the in-
terior of the corpuscula. Schleiden,§ in 1843, gave the
first accurate account of the nature of the pro- embryo. As
many subsequent observers have done, he mistook the

* 'Ann. d. Sc.' 1st ser., vol. viii, p. 211.

f 'Ann. d. Sc' 2nd ser., vol. xx, p. 193.

% ' Nova Acta/ vol. xvii, p. 599. Upon other points this work is of no
use.

§ ' Grundziige,' 1st edn., vol. ii, p. 375. R. Brown's account of the young
pro-embryo is incomplete. He figures (1. c, vol. xx, pi. v, fig. 9) a pro-embryo
whose smaller terminal growing cells arc torn off.

THE HIGHER CRYPTOGAMIA. 433

pro-embryo for the embryo. Hartig* was the first to
observe that the upper part of the suspensor is a single
row of cells. He had not a clear idea of the relation of the
suspensor to the pro-embryo. Mirbel and Spachf dis-
covered the breaking up of the pro-embryos into single
rows of cells in Pin as, Thuja, and Taxus. Gottsche'sj
excellent work contains the most careful critique of the then
known facts, and the first accurate description of the struc-
ture of the corpuscula of Pinus ; it also gives a renewed
and complete proof of the advance of the pollen-tube to the
corpuscula, as well as proof of the fact that the rudiment
of the pro-embryo is visible in the lower end of the cor-
pusculum, whilst the sister-cells of the germinal vesicle are
still present.

The greater part of the above investigations were under-
taken in the years 1848 and 1849.§ I have already
mentioned their agreement with Pineau's views, and their
divergence from those of Geleznow and Schacht.

* ' Naturgeschichte der Forstcultur pflanzen,' Erklarung zur Tafel, XXV.

f ' Ann. d. Sc. nat.,' ii Ser. vol. xx, p. 257.

% 'Bot. Zeit./ 1845, 377.

§ Read at the August sitting of the Leipzig Natural History Society.

2S

CHAPTER XVI.

REVIEW.

The comparison of the development of the mosses and
liverworts on the one hand, with that of the ferns Equiseta-
cese, Rhizocarpese, and Lycopodiaceae on the other, dis-
closes the most complete uniformity between the fruit-
formation on the one hand and the embryo-formation on the
other. The structure of the archegoniuni of the mosses —
the organ within which the fruit-rudiment is formed — is
exactly similar to that of the archegonium of the vascular
cryptogams, the latter being that part of the prothallium in
the interior of which the embryo of the frond-bearing
plant originates. In both the large groups of the higher
cryptogams there is a cell which originates freely in the
larger central cell of the archegonium, by the repeated
division of which (free) cell, the fruit of the moss and the
frond-bearing plant of the fern are produced. In both,
the divisions of this cell are suppressed and the arche-
gonium miscarries, unless, at the time of the opening of
the top of the latter, spermatozoa find their way to it.

Mosses and ferns therefore exhibit remarkable instances
of a regular alternation of two generations very different
in their organization. The first generation — that from the
spore — is destined to produce the different sexual organs,
by the co-operation of which the multiplication of the
primary mother-cell of the second generation, which exists
in the central cell of the female organ, is brought about.
By this multiplication a cellular body is produced which in
the mosses forms the rudiment of the fruit, and in the
vascular cryptogams, the embryo. The object of the

HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 435

second generation is to form numerous free reproductive
cells — the spores — by the germination of which the first
generation is reproduced. The leafy plant in the mosses
answers therefore to the prothallium of the vascular
cryptogams ; the fruit in the mosses answers to the fern
in the common sense of the word, with its fronds and
sporangia. The pro-embryo, that is to say the confer-
void process produced by the germinating spore of most
of the mosses and many of the liverworts, cannot be
looked upon as a special generation any more than the
similar organ (the suspensor) m phsenogams. It is to be
remembered that when new individuals are produced from
single cells of the leaf of a moss, and also during the
development of the gemmse of many mosses, the formation
of the rudiment of the first leafy axis is preceded by the
formation of a similar confervoid pro-embryo. This holds
good as well in the mosses * as in those liverworts which
possess a pro-embryo. When new individuals are formed
from the fragment of a leaf of Lophocolea heterophylla or
of Badula complanata, the cell of the surface of the leaf
which becomes the mother-cell of the new plant produces
in the former of the above-named plants a single or double
row of cells, and in the latter a cellular surface. In each
case the body produced is exactly similar to the pro-
embryo which originates from the germinating spore in
both species.

The vegetative life of the mosses is confined exclusively
to the first, and the fructification to the second generation.
The leafy stem alone sends forth roots : the spore-forming
generation draws its nourishment from the first generation.
The life of the fruit is usually much shorter than that of the
leaf-bearing plant. In the vascular cryptogams this state
of circumstances is reversed. It is true that the prothallia
send out capillary roots : this is always the case in the
Polypodiaceae and Equisetacese, and frequently in the
Rhizocarpese and Selaginellae. But the prothallium lives a
much shorter time than the leaf-bearing plant, which latter
in most cases does not produce fruit for several years.

* W. P. Schimper's excellent work, ' Recherches sur les mousses,' renders
it unnecessary for me to cite examples.

43G HOIMEISTEH, ON

The contrast however is not so marked as it appears at first
sight. The apparently unlimited life of the leaf-bearing
moss depends merely upon continual renovation. Pheno-
mena of a similar kind are met with in the sprouting
prothallia of Polypodiacese and Equisetaceae. In the lowest
liverworts (Anthoceros and Pellia) the structure of the
fertile shoots is less complicated, and their duration little
longer, than that of the fruit. On the other hand the
ramification of the prothalliuui of the Equisetaceae is very
variable ; its life is not of shorter duration than that of an
individual shoot.

It is a circumstance worthy of notice that in the second
or spore-forming generation of mosses and ferns, compli-
cated thickenings of the cell-walls usually occur (witness
the teeth of the peristome in mosses, the capsule-wall and
the elaters in liverworts, and the vessels in ferns), whilst in
the first generation these thickenings are rare and excep-
tional.

An unprejudiced consideration of the subject will show
that the separation into two groups only of the plants com-
prising the mosses on the one hand, and the liverworts
(Jungermanniae, Marchantieae, Anthoceroteaa, and Riecieae)
on the other, is not natural. There is no marked feature
by which these two groups can be distinguished. It is
true that a pro-embryo like that in the mosses is wanting
in most of the genera of liverworts, especially in all the
leafless ones. Many leafy Jungermamrieae, however, espe-
cially the true Jungermanniae, exhibit the phenomenon of
the conversion of the germinating spore into a single row
of cells, one of which cells, by repeated divisions in all
three directions of space, becomes the rudiment of the leafy
axis. This phenomenon is as well marked as in any of the
mosses. The outward form of the antheridia and arche-
gonia in the two groups differs very slightly. The first
stages of development of the fruit-rudiment of the mosses
on the one hand and the Jungermanniae on the other, are,
it is true, very different. In the former the longitudinal
growth is caused by the continually repeated division of a
single conical apical cell of the organ, by means of septa
inclined alternately in two directions ; in the latter this

THE HIGHER CRYPTOGAMIA. 437

growth is caused by the repeated division by horizontal
septa, of four cells constituting the upper end of the fruit-
rudiment. But the normal mode of cell-multiplication in
the fruit-rudiment of the Marchantieae (including the
Targionieae), and of the Riccieae, coincides exactly with
that of the mosses. Lastly Anthoceros exhibits a form of
cell-multiplication of the endogonium which is the same
as that of the punctum vegetationis of the ends of the axes
of a great number (probably the majority) of phaenogams.
The septa produced in the one apical cell of the organ, are
inclined in regular succession towards the four points of
the compass. The presence or absence of a columella, or
of elaters in the ripe fruit, are points of no characteristic
value ; Anthoceros has the columella, but this genus and
the Riccieae have no elaters. Radula in the Jungerman-
nieae has a vao-irmla, and so has Anthoceros.

Upon instituting a closer comparison between the mode
of development of different forms, four types soon become
conspicuous, around which all the phenomena hitherto
sufficiently investigated may be conveniently arranged.
We thus arrive at the following equivalent groups, which
are not however equally rich in the number of genera and
forms.

1. Mosses according to the ordinary limits of the family,
including the Sphagnaceae.

2. Jungermannieae ; in which the leafy ones are con-
nected with the leafless ones by a succession of inter-
mediate stages.

3. Marchantieae, Targionieae and Riccieae; all intimately
connected with one another by the similarity of the earliest
conditions of the fruit, as well by many vegetative pheno-
mena.*

4. Anthoceroteae.

The mode in which the second generation originates
from, the first is much more various in the vascular crypto-
gams than in the others. All ferns however agree in the

* As for instance the precisely similar succession of the shoots ; the separa-
tion of the tissue of the shoots into an upper layer with intercellular caviiies,
and a lower layer without cavities ; the occurrence of peculiar thickenings upon
the inner wall of the capillary roots, &c.

438 HOFMEISTER, ON

fact that the first axis of their embryo has only a very
limited longitudinal development ; it is an axis of the second
order which breaks through the prothallium and becomes
the principal axis ; and they all agree further in this, that
the end of the axis of the first order never forms the root.
All vascular cryptogams are without main roots ; they have
only adventitious ones.

In more than one respect the formation of the embryo of
the Coniferse is intermediate between the higher crypto-
gams and the phsenogams. Like the primary mother-cell
of the spores of the Rhizocarpeae and Selaginellae the
embryo-sac is one of the axile cells of the shoot, which in
the one case becomes 'converted into the sporangium, in
the other into the ovule. In the Coniferse also the embryo-
sac soon becomes free from any mechanical connexion with
the surrounding cellular tissue. The filling of the embryo-
sac by the endosperm may be compared with the produc-
tion of the prothallium of the Rhizocarpeae and Selaginellae.
The structure of the corpuscula bears the most striking
resemblance to that of the archegonia of the Salviniae, and
still more of the Selaginellae. Irrespective of the different
mode of impregnation — which in the Rhizocarpeae and
Selaginellae takes place by free spermatozoa, and in the
Coniferee by a pollen-tube, in the interior of which sperma-
tozoa are probably formed — the transformation of the
germinal vesicle into the primary mother-cell of the new
plant in the Coniferae and the vascular cryptogams, only
differs in the fact, that in the latter there is usually one
single germinal vesicle only, whilst in the former there are
very numerous germinal vesicles, of which, normally, one
only is impregnated. The embryo-sac of the Coniferae
may be looked upon as a spore remaining enclosed in its
sporangium ; the prothallium which it forms does not come
to the light. In order to reach the archegonia Of this
prothallium the impregnative matter must make itself, a
passage through the tissue of the sporangium.

Moreover, the development of the pollen of the Coniferae,
when dispersed, varies in a marked manner from that of
phaenogams, and exhibits vital phenomena similar to those
met with in the microspores of Pilularia, Salvinia, and

THE HIGHER CRYPTOGAM I A. 439

Isoetes. The extinction of its sexual function (the protru-
sion of the pollen-tube) is preceded by a cell-formation in
its interior, of which no instance is to be found amongst
monocotyledons and dicotyledons.

Two of the phenomena which have led me to compare
the embryo-sac of the Coniferse with the large spores of the
higher cryptogams, is common to the embryo-sac of phseno-
gams, viz., the origin of the ovule from an axile cell, and
the want of connexion with the adjoining cellular tissue.
This is very remarkable in the Rhinanthaceae on account of
the independent growrth of the embryo-sac. The Coniferse
are closely allied to the phsenogams in the fact that their
pollen-grains develope tubes.

The phasnogams therefore form the upper terminal link
of a series, the members of which are the Coniferse and
Cycadeae, the vascular cryptogams, the Muscineae, and the
Characeae. These members exhibit a continually more
extensive and more independent vegetative existence in
proportion to the gradually descending rank of the gene-
ration preceding impregnation, which generation is deve-
loped from reproductive cells cast off from the organism
itself. The closing members of this series, the Characeae,
pass through their entire vegetative development in this
generation, whilst the vital phenomena of the generation
which follows impregnation are limited to the filling with
oil and starch of the newly formed cell in the central cell
of the fruit-branch or archegonium. The development of
the latter generation in the Muscinese is far more important,
although in some instances, as for example in Riccia, it is
very limited in comparison with the first generation, that
namely which precedes impregnation.* This state of things
is reversed in the Ferns, the Equiseta, and the Ophioglossese.
From the Characeae up to these orders, there is an uncer-

* Anthoceros— 'which in the development of the second generation stands
very low in the scale — exhibits a remarkable analogy with the Characeae, in the
fact that, as in the latter, the formation of its antheridia commences by the
growing out of the cells of the wall of an intercellular cavity. The well-known
red globules of Chara are manifestly states of antheridia. Cavities com-
municating with one another are formed round the middle point of the hitherto
solid globular mass of cells, within which cavities the antheridia — or cellular
threads in whose joints the vesicles which produce the spermatozoa arc formed
— become developed.

440 HOFME1STER, ON

tainty in the different species as to the sexual function of
the reproductive cells which are cast off from the organism
itself, viz., the spores. In these orders species nearly allied
to one another are partly mona?cious and partly dioecious.
Certain species amongst theCharae,Muscineae, the Ferns, and
the Equiseta,* produce both kinds of sexual organs, arche-
gonia and antheridia, upon the same individual of the genera-
tion preceding impregnation : the latter are always produced
before the former. In other Characeae, Muscineae and
Equiseta, the male and female sexual organs are distributed
upon different individuals — a separation which is very com-
plete in certain species of mosses, and not in others. The
spores from which, in the Characese, Muscinae, and Equi-
seta, diaecious prothallia are developed, exhibit no indica-
tion of the sex of the individual to be produced from them.
But there is often a marked difference in the complete form
between the male and female individuals : the former are
much smaller than the latter ; they are dwarfish. Extreme
instances of this are to be found, amongst mosses, in
Dicranum tin elided inn and Hi/pnum h/tescens. In the Equi-
seta also the male prothallia are always smaller than the
females.

Lastly, the reproductive cells of the Ttldzocarpece, Isoetes,
and Selaginella exhibit, according to their sex, the most
remarkable differences in their mode of development, size,
and form, so long as they continue in vital connexion
with the organism belonging to the generation following
impregnation. In the Coniferae the reproductive cells differ
in their origin and formation but little from those of phae-
nogams ; they differ only in the nature of the vegetative
growth subsequent to their formation — which growth in
the Coniferae is in a high degree independent — in the
formation of the row of cells in the interior of the pollen-
grain, as well as in the formation of the endosperm, and of
the corpuscula in the interior of the embryo-sac.

There are so many essential points of agreement between
the Coniferae and the phaenogams, that it is more to the
point to get rid of the marked differences in their respective

* The greater number of the Charseand Muscineae, a few only of the Equi-
seta, and all the known forms of Ferns and Ophioglossese.

THE HIGHER CRYPTOGAMIA. 441

processes of embryo-formation, than to indicate in what they
agree. One of these differences is the cell-formation inside
the pollen-grain, but the principal one is the development
of the endosperm and of the corpuscnla, a process exactly
analogous to the formation of the prothallia and archegonia
of the vascular cryptogams, and which is entirely wanting
in the phaenogams. The whole series of developmental
processes which occur in the Coniferae between the filling
of the embryo-sac with the cellular tissue of the endosperm
and the production of the germinal vesicles in the corpus-
cnla, is entirely passed over in the phaenogams. Here the
germinal vesicles are formed immediately in the embryo-
sac. In the phaenogams there is no vital phenomenon
analogous to the development of the prothallia and of the
endosperm of gymnosperns, just as in the cryptogams and
the Coniferae there is no analogue to the endosperm-
formation which takes place in so many phaenogams after
the arrival of the impregnating organ at the embryo-sac.
The breaking up of the pro-embryo of the Coniferae into
a number of independent suspensors is a phenomenon of
the most peculiar kind, to which nothing amongst the vas-
cular plants bears any resemblance,* and to which the
division of the spore (i. e. the mother-cell of the oospores)
of Fucus into several cells capable of impregnation and
developmentt is hardly analogous, inasmuch as with the
latter process the impregnation of the free spore commences
and forthwith terminates.

The observations contained in the following note are the
result of investigations made subsequently to those detailed
in Chapter III. These inquiries have led to the conclusion
that Frullania — and probably also Lop hocolea bidentata and

* The formation of the pro-embryo of Loranthus europaus out of four longitu-
dinal rows of cells may be looked upon as a slight indication of this. One only
of these cells, the terminal cell, becomes transformed into an embryonic globule.
CHofmeister, in ' Abh. Kon. Sachs. Ges. d. Wiss./ vi, 543.
' f Thuret, « Ann. d. Sc. Nat.,' iv Ser., 1854, p. 273.)

142 IJOFMEIS'IER, ON THE HIGHER CRYPTOGAMIA.

Ptilidium ciliare-- — must be excluded from the category of
plants having a two-edged terminal cell of the stem.

Note on the Cell-multiplication of the Apeos of the Stem
in the Leafy Jungermannice.

The end of the stem in vigorous shoots of Jungermannia
hicuspidata exhibits, when viewed from above, a three-
sided apical surface of the terminal cell, and an arrangement
of the cells adjoining the latter, which leads to the con-
clusion that the cells of the second degree are formed
by the production of septa in the apical cell parallel to
each one of the three plane lateral surfaces. The order of
succession of the cells of the second degree represents a
spiral. All those Jungermannia? which I examined which
had inferior leaves, and consequently trilinear phyllotaxis,
exhibited a similar state of circumstances — for instance,
Alicularia scalaris, Calypogeia Trichomanes, Lepidozia
reptans, Frullania dilatata, Madotheca platyphylla. The
same was the case also with another Jungermannia — besides
J. hicuspidata — with bilinear-leaves, viz. Plagiochila as-
plenioides. In the latter — as in /. hicuspidata — a leaf
originates out of .each cell of the two longitudinal rows of
cells of the second degree which are turned upwards to-
wards the creeping stem. Each of the cells of the longi-
tudinal row of cells of the second degree which occupies
the under surface of the stem, developes from its fore-edge
a transverse row of two- or three-celled hairs with elongated
clavate terminal cells, which hairs soon fall off.

EXPLANATION OF THE FIGURES.

PLATE I.

ANTHOCEE.OS luEVIS.
FIG.

1. Germ-plants seen from above, x 15.*

2. Shoot of a plant cultivated for some time in a room under a hand-glass,

X 15.

3. Longitudinal section through an actively growing shoot, perpendicular to

the surface. The contents are only shown in the cells of the fore-edge.
The youngest cell of the second degree belongs to the upper side of the
shoot. The fore-edge of the shoot is surrounded by a layer of mucilage,
hardened on the outside, to which grains of dust and sand adhere.
X 300.

4. A similar preparation. The section has passed through three archegonia in

process of development. X 300.

5. A young shoot seen from above, X 300.

6. Fore-edge of a half-developed shoot in the epidermal cells of which the

final division is going on, x 300.

7. A young shoot ; on the right and left of the middle shoot are the two

rudimentary lateral shoots, seen from above, x 300.

8. Transverse section of a delicate young shoot, X 200.

9. Cells of the interior of a perfect shoot cut through longitudinally, and

which, abnormally, contain two chlorophyll-granules, X 300.

10. Portion of a section perpendicular to the surface of a perfect shoot, treated

with caustic potash, X 300.

11. Portion of the inner tissue of a longitudinal section of a perfect shoot.

One of the cells — that one whose contents are figured — shows the com-
mencement of the formation of a gemma. X 300.

12. A further developed gemma cut through parallel to the surface of the shoot

in which it was formed, x 300.

13. A gemma which has sent out a capillary root whilst still within the decay-

ing tissue of the mother-shoot, X 100.

14. Chlorophyll-bodies from one of the cells of the wall of a young fruit,

X 400.

* " x 15" means "magnified 15 diameters," and so on all through the

figures.

444 EXPLANATION OF THE FIGURES.

FIG.

14*. A similar body in the act of dividing, x 400.

15. A young archegonium with the adjoining tissue, cut through longitudinally,

X 300.

16. An archegonium more fully developed, after the formation of the germinal

vesicle in the basal cell, x 300.

17. Portion of a longitudinal section of a shoot perpendicular to the surface,

bearing an archegonium just impregnated. A bud which has been cut
through is seen in the tissue underneath, x 300.

18. Longitudinal section of an archegonium (with the adjoining cells) with a

bicellular fruit-rudiment, x 300.

18*. The mouth of the latter seen from above, X 300.

19. A similar preparation with a multicellular fruit-rudiment, x 300.
20a. A 3-cellular fruit-rudiment, detached, x 300.

20*. The same preparation turned round 90°, X 300.
21". Longitudinal section of a further developed fruit-rudiment, x 300.
21*. The apex of a detached fruit-rudiment, similarly developed, seen from the
outside, x 300.

21c. Optical section of the preparation in the same position, X 300.

21 d. Optical sectiou of the same after being turned 90° round its longitudinal
axis.

22. Longitudinal section of a further developed fruit-rudiment, X 250.

23"'*. Optical longitudinal sections of the upper end of a more advanced fruit-
rudiment. The position of 23* differs from that of 23" by a revolution
of 90° round the longitudinal axis, x 250.

24. Transverse sections of a similar fruit-rudiment, x 80.

25. Apex of a slightly more developed fruit-rudiment, separated from the lower

portion by a transverse section, and seen from above, x 150.

PLATE II.

1. Longitudinal section of a young fruit-rudiment enclosed by the surround-

ing tissue, x 150.

2. Longitudinal section of a further developed condition of the same parts.

A large cavity filled with mucilage has been formed above the apex of
the fruit-rudiment. Some of the cells of the wall have grown out into
multicellular hairs, x 120.

3. Upper portion of the wait-like protuberance (above the upper surface of

the stem) by which the young fruit is enclosed ; cut off so that the upper
end of the fruit is visible. The cells of the jointed hairs which traverse
the mucilaginous mass in the interior of the cavity above the fruit, have
already become detached. X 100.

4. Longitudinal section of the upper end of a fruit at the moment of breaking

out from the sheath. Only the mucilaginous mass and the dry cellular
tissue covering it are shown in detail ; the fruit and the sheath are only
in outline, x 200.

5. Longitudinal section of a half-developed fruit just after breaking forth

from the tissue of the stem, x 100.

EXPLANATION OF THE FIGURES. 445

FIG.
5*. The cast-off calyptra (consisting of the ruptured portion of the tissue of
the stem, which covered the cavity, together with the mucilage which
filled the latter), seen from below, x 100.
5". Some of the cells of the edge of this calyptra, x 300.

PLATE III.

1. Columella and right-hand longitudinal moiety of the lower part of a young

fruit, the place at which the separation of the grand-mother-cells from
the surrounding tissue commences, X 250.

2. Transverse section (high up) of a young fruit, x 100.

3. Spore-mother-cells, just detached, x 250.

4. 5 and 5*. Spore-mother-cells during the formation of the two secondary

nuclei, x 250.
6. A similar cell after the formation.

7 and 8. The same cells during the dissolution of these nuclei.
9. Spore-mother-cell after the formation of the four tertiary nuclei, x 250.

10. The same shortly before the commencement of division, showing the begin-

ning of the swelling of the cell-membrane.

11. Spore-mother-cell (after the dissolution of the primary nucleus) in alcohol

and water, which makes the cell-membrane swell, x 750.

12. Spore-mother-cell at the commencement of division, examined in alcohol,

X 750.

13. A similar preparation after treatment with water, which makes the cell-

membrane swell, x 750.

14. Spore-mother-cell in alcohol before the termination of the division. The

course of the edges of the septa — which do not yet reach the middle
point of the cell — upon the inner side of the cell-membrane is shown in
the drawing, x 750.

15. An abnormal spore-mother-cell, x 250.

16. Longitudinal section, perpendicular to the surface, of the end of a shoot

which bears a group of rudimentary antheridia, x 300.

17. Optical longitudinal section of two young antheridia, x 150.

18. Optical transverse section of one of these antheridia, x 150.

19. 20. Optical longitudinal section of more-developed antheridia, x 300.

21. Longitudinal section of an almost ripe antheridium, x 300.

22. Two mother-cells of spermatozoa, each containing a spermatozoon, x 500.

PLATE IV.

PELLIA EPIPHYLLA.

1. Longitudinal section of a ripe spore, x 300.

2. Sketch of a ripe spore in which the outlines of the cells only are shown,

446 EXPLANATION OF THE FIGURES.

FIG.

3. A ripe spore beginning to germinate, three days after sowing, x 300.

5 — 9. Germinating spores more developed; six days after sowing, x 100.

Fig. 6 is fig. 5 turned round 45°; fig. 7 is the same object turned round

90°; fig. 8 turned round 270°.

1 0. A germinating spore whose first capillary root is just breaking through the

exosporium, x 300.
11 — 14. Sections of spores more advanced in germination ; figs. 11 and 14 seen

from above, figs. 12 and 13 from the side. Figs. 11 — 13 are magnified

300, fig. 14, 150 times. Figs. 13 and 14 represent spores eleven days

after sowing.

15. Fore-end of a somewhat more developed germ-plant, 36 days after sowing,

seen from above, x 200.

16. Longitudinal section of a similar fore-end, x 200.

17. Fore-end of a germ-plant 42 days after sowing, x 200.

18. Germ-plant 49 days after sowing, x 30.

19 — 22. Half-developed spring shoots of fertile specimens, x 5.

23. Half-developed spring shoot seen from above, x 200.

24, 25. Longitudinal section, perpendicular to the surface, of half-developed

shoots of fertile plants— fig. 24, x 200 ; fig. 25, x 400.

26, 27. Longitudinal section, perpendicular to the surface, of young shoots of
barren plauts, x 200.

28. Transverse section of an older shoot of a barren specimen which bears four

rudiments of adventitious shoots. Very delicate fungoid threads are
seen upon the outer surfaces of the epidermal cells of the mother-shoot.
X 200.

29. Longitudinal section of a rudimentary antheridium, x 300.

30. Longitudinal section of an unusually slim antheridium almost ripe. The

contents of the cells, and the mother-cells of the spermatozoa, are not
shown, x 200.

31">J. Mother-cell of spermatozoa from an unripe antheridium, x 600.
32"' *. The same after its escape from a ripe antheridium. The included spiral
spermatozoon is already revolving, x 600.

333'*'c. Free spermatozoa, killed by iodine. In 33" and 33c the mother-cell is
attached to the hinder end. x 600.

PLATE V.

r-ELLIA EPIPUYLLA.

1. Vertical longitudinal section of a shoot bearing the rudiments of archego-

nia, x 30.

2. A similar shoot with more developed archegouia, x 30.

3. Longitudinal section of a very young archegonium, x 400.

4. Longitudinal section of the upper end of a somewhat more developed

archegonium, x 300.

EXPLANATION OF THE FIGURES. 447

FIG.

5. A young archegonium at the time of the dissolution of the transverse septa

of the cells of the axile cellular string, X 300.

6. Longitudinal section of an archegonium fit for impregnation, X 200.
C*. Transverse section of the neck of a similar archegonium, X 200.

7. Similar view of au archegonium ready for impregnation and of a very young-

one similarly magnified, X 200.

8. Three-celled fruit-rudiment, detached, x 300.

9". Group of three archegonia impregnated artificially, with two young abortive
archegonia, X 40.

9*. Young fruit-rudiment, longitudinal section.

10. Longitudinal section of a more developed fruit-rudiment, X 300.

11. Longitudinal section of a young fruit, showing the commencement of the

separation of the tissue of the interior of the capsule (about the 20th
August), x 150.

12. Primordial utricle of a cell of the interior of a capsule in the same state

of development, set free by the dissolution of the swollen substance of
the wall, x 200.

13. Longitudinal section of a further developed fruit, x 40. In part of the

interior of the capsule the arrangement of the elaters and spore-mother-
cells is visible (middle of September).

14. Spore-mother-cell with protrusions (one turned away from the observer) of

the wall ; on the 8th of September, x 500.

15. The same, in which the cell-contents are not shown, x 500.
15^. The same, turned round 90°, x 200.

16. Mother-cell with four protrusions (one turned away) answering to the

special-mother-cells. Beginning of December, x 400.

17. A set of four spores just formed (one is turned away from the observer)

which are held together by the remnants of the mother-cell. Middle of
December. X 400.

18. A young spore still attached to the remnants of the mother-cell. In the

place of the primary central nucleus (which in the spores shown in
Fig. 17, has already become dissolved) two new ones have been
formed. X 400.

19. The same division has taken place in the two halves of the spore which is

still attached to the remains of the mother-cell, x 400.

20. Remnants of the mother-cell from which the spores have escaped, x 400.

21. A septum is formed between the two nuclei dividing the spore into two

halves, x 300.

22. One of the two newly formed cells has divided again by a transverse

septum, x 300.

23. Outlines of the cells of a five-celled spore, x 400. On the 20th Decem-

ber.

24. A free spore similar to that in Fig. 7, X 400.

25. A young spore, one half of which has become divided irregularly by an

oblique septum, x 300.

The originals of Figs. IS, 19, 20, 22 and 24, were taken from the same cap-
sule as the original of Fig. 17.

448 EXPLANATION OF THE FIGURES.

PLATE VI.
Figs. 1 — 10. Aneura mullifida.

FIG.

1. A delicate branch seen from above, x 10.

2. Fore-end of a growing shoot, seen from above, x 400.

3. Longitudinal section of a similar shoot. (The section has not touched the

cell of the first degree.) x 300.

4. Longitudinal section of inflorescence, with a fruit-rudiment lately formed,

and enclosed by a calyptra already much enlarged, X 50.

5. Very young fruit-rudiment, detached, x 300.

6. Longitudinal section of a more advanced fruit-rudiment, x 150.

7. Longitudinal section of the upper part of the fruit-rudiment at the com-

mencement of the formation of the capsule, x 400.

8. Fruit-rudiment somewhat more advanced, enclosed by the large calyptra

which is cut through longitudinally. On the left near the calyptra are
two abortive archegonia. x 50.

9. Longitudinal section perpendicular to the surface through the gemmiferous

portion of a shoot. In one of the epidermal cells a bud is in process of
formation. A two-celled bud lies loose in another epidermal cell which
has been torn, x 300.

10. Two gemmae, one seen from the side, the other (which is about to send out

a capillary shoot) seen from the front.

Figs. 11 — 15. Aneura ping 'ids.

11. Fore-end of a growing flat shoot seen from above, x 400.

12. Longitudinal section perpendicular to the surface of a thicker shoot. It

bears the rudiment of an antheridium. x 300.

13. A similar longitudinal section not exactly through the middle of the shoot,

X 300.

14. A young antheridium seen from the outside, x 300.

15. Rudiment of an archegonium seen from above, the microscope being

focussed somewhat below the apex of the organ, X 300.

Figs. 16 — 24. Blasia pusilla.

16. Barren gemmiferous shoot seen from below, X 25.

17. Growing fore-end of a shoot seen from above, X 200.

18. End of a delicate shoot after the removal of the under leaves, seen from

below, X 400.

19. Section perpendicular to the surface through the fore-end of a growing

shoot, X 200.

20. Similar section of a shoot where the latter has a bud-receptacle in process

of formation, x 200.

21. Longitudinal section of a further developed bud-receptacle, X 60.

22. Portion of a longitudinal section of a less developed bud-receptacle, upon

the inner wall of which rudimentary gemmae, in different stages of
development, are seated, x 200.

EXPLANATION OF THE FIGURES. 449

FIG.

224. A portion of the uppermost bud of the former figure, x 600. The dotted
lines show the course of the two nuclei during the molecular motion
which they exhibited.

23. Two spore-mother- cells held together by the common membrane of the

mother-cell, after the formation of the tertiary nuclei, X 300.

24. A similar mother-cell somewhat more developed, X 300.

Figs. 25 — 376. Fossomlrotiia pitsilla.

25. Two-celled rudiment of a leaf, X 300.

26. A young leaf with eleven cells, x 300.

27. 28. Tips of somewhat more developed leaves, x 300.

29, 30. Sections of young archegonia, fig. 29, x 100 ; fig. 30, x 400.

31. Section of au archegonium in whose central cell the germinal vesicle is

being formed, x 300.

32. Section of an archegonium in whose central cell the germinal vesicle is

completely formed, and the primary nucleus almost dissolved, X 300.

33. Longitudinal section of an archegonium, with its central cell almost filled

by the germinal vesicle, X 300.

34. Spore-mother-cell, after the formation of the four tertiary nuclei, X 300.

35. Mother-cell from the same capsule, after long soaking in water. The inner

layer of the cell-membrane is much swollen, and has squeezed the con-
fluent cell-contents into a globular lump, x 300.

36. Young elater from the same capsule after soaking in water for a short time.

The middle layer of the cell-membrane is thuch swollen, and has ruptured
the outermost one. x 300.

37. Longitudinal section of a ripe autheridium whose apex has burst by the

separation of the cells and the tearing of the cuticle, x 150.

37*. Ruptured mother-cellule of a spermatozoon, which is escaping out of the
fissure, x 600.

PLATE VII.

Figs. 1 — 3. Haplomitrium Hookeri.

. Longitudinal section of the apex of a leafless subterranean shoot, x 300.

2. Similar section of a similar shoot farther from the apex, X 300.

3. Similar section of a detached young fruit rudiment, x 300.

4. Trichocolea tomentella. — Longitudinal section of a terminal bud, X 200.

5. Madotheca platyphylla.— Longitudinal section of an autheridium, x 200.

6. Ripe mother-cell of a spermatozoon from the same.

Figs. 7—9. Ptilidlum Ciliare.

7. Half of a young leaf, x 150.

8. A young leaf slightly more developed, detached from the stem and ex-

panded, x 200.

9. Lateral view of a terminal bud, which has developed a lateral branch close

underneath the apex.

29

i

450 EXPLANATION OF THE FIGURES.

Figs. 10 — 11. Alicularia scalaris.

FIG.

10. End of the stem being a half-ripe fruit, in a longitudinal section which

has grazed the capsule and laid bare the outer surface of the fruit-stalk
and of the swelling at its lower end, x 30.

11. Longitudinal section of a germ-plant, x 300.

11*. A young leaf detached from the stem spread out, X 100.

12. Jungermannia hicuspidata. — An archegonium just impregnated, and an un-

impregnated one ; both laid open by a longitudinal section passing through
the perianthium, which already extends far above the archegonium, and has
the apices of its edges inclined towards one another. In the inner cavity
of the perianthium several moving spermatozoa were found ; the arrow
shows the direction of their motion, x 400.

Figs. 13 — 20. Jungermannia divaricata.

13. Longitudinal section of a rudimentary archegonium, X 600.

14. Longitudinal section of a perianthium containing only two young arche-

gonia, x 600.

15. Archegonium ready for impregnation (or just impregnated ?), cut through

longitudinally so that the knife passed through the central cell, x 600.

16. The germinal vesicle detached from the central cell of a similar archegonium.

The cell-membrane has been injured by the dissecting needle; the
nucleus escaped out of the fissure, and lies near it, x 500.

17. Longitudinal section of a*- impregnated archegonium which has grazed the

two-celled fruit-rudiment. At the apex of the archegonium, between
the globular lumps of glassy transparent mucilage, thread-like bodies,
like spermatozoa are seen, x 600.

18. A young, and 19, a somewhat older fruit-rudiment, the former seen from the

outside, the latter in longitudinal section, x 400.
20. Longitudinal section of a more developed fruit, x 250.

PLATE VIII.

Figs. 1 — 20. Jungermannia bicuspidata.

1. A very young perianth laid open by a longitudinal section, with three arche-

gonia still closed at the apex, x 300.

2. Longitudinal section of an archegonium ready for impregnation, x 300.

3. Similar section of a somewhat more developed perianth. In the middle is

an archegonium just impregnated ; near the latter are two unimpregnated
ones, with ruptured apex ; on the outside are two still undeveloped.

4. Four-celled fruit-rudiment detached, x 300.

5. Young fruit-rudiment. 5*. The same turned round 90°. 5C. A similar

fruit-rudiment detached. X 300.

6. Longitudinal section of the lower part of a perianth enclosing two fruit-

rudiments, x 250.

EXPLANATION OE THE FIGURES. 451

PIG.

7. Longitudinal section of a half-ripe fruit, with the calyptra, two abortive
archegonia, and the lower part of the perianth, x 200.

8 and 9. Young leaves which have not yet formed the rudiments of the two
tips, x 500.

"10. A further-developed leaf, X 500.

11. Tip of a half-developed leaf, x 300.

12. Section of the tip of a leafless subterranean shoot ; 12*, section of the same

shoot after being turned round 90°. x 300.

PLATE IX.

Figs. 1.— 12. Jungermannia bicuspidata.

1. Ripe spore, x 300.

2 — 10. Different stages of germination. 2, 3 one week. 4, 5 three weeks.
6, 7 four weeks after sowing. 8 — 10, germ-plants a year old. 2 — 6,
X 300 ; 7, X 200 ; 8, 9, 10, x 100 ; 10* is the upper end of fig. 10 ;
turned rouud 90° and x 400.

11. Fore-end of a germ-plant at the stage of development shown in fig. 8, seen

from the outside. The boundaries of the cell of the first degree, and of
the first cell of the second degree, as they appear in an optical section,
are shown by dotted lines, as is done also in the following figures.
X 400.

11*. The same. The apex of the stem turned round 90°.

IP. The same, turned round 270°.

IP*. The apex of the stem of a more-developed germ-plant, in a position inter-
mediate between that of*figures 11 and 11*, seen from the outside,
X 400.

12. An abnormal pro-embryo, in which the rudiment of the first leaf-bearing

axis does not proceed from one of the apical cells of the pro-embryo,
but springs from a poiut lower down (five months after sowing),
X 200.
12*. Rudiment of the leafy axis, turned round 90°.

Figs. 13 — 16. Lophocolea bidentata.

13. Longitudinal section of a terminal bud, X 600.

14. A very young, 15 a somewhat older leaf seen from above, X 600.

16 A more developed leaf, the two halves of which have developed unequally,
X 300.

Figs. 17 — 30. Lophocolea heterophjlla.

17 — 25. Germination of the spores; (17, a spore just detached, 18 a spore
twenty-four hours afterwards), x 200 except fig. 23, which is X 600.

26. Production of the first leafy axis out of the pro-embryo, X 250.

27. More advanced germ-plant, whose hinder end is already dead, X 200.

28 Lower portion of a germ-plant which has already formed some perfect leaves,
X 100.

452 EXPLANATION OF THE FIGURES.

TIG.

29. Portion of the stem of a young plant, lateral view of the outer surface.

The inner edges of contact of the cells are shown by dotted lines,
x 150.

30. Longitudinal section of the upper end of a young archegonium, X 200.

Figs. 31, 32. Jungermannia intermedia.

31. Longitudinal section of a half-ripe antheridium, X 300.

32. Similar section of a young fruit-rudiment of the same plant, X 300.

Figs. 33, 34. Jungermannia trichophylla.

33. Longitudinal section of a young fruit, x 200.

34. A set of special-mother-cells out of the same fruit, x 600.

PLATE X.

CALYPOGEIA TEJCilOMANES.

1 and 6. Longitudinal sections of young fruit-branches, X 200.

2, 4, 5. Detached fruit-rudiments seen from the outside, figs. 2 and 4, X 300,

fig. 5, X 150.

3, 7. Longitudinal sections of similar fruit-rudiments, x 300.

8. Longitudinal section of the lower part of a young fruit-sac, x 200.

PLATE XL

Figs. 1 — 7 and 15 — 26. Badula complanata.

1. Lateral view of an inflorescence ; the antheridia and archegonia are repre-

sented in section ; the cell contents are not shown.

2. A very young, 3 a half- ripe antheridium, both in longitudinal sectiou,

X 500.

4. Longitudinal section of a more developed fruit-rudiment, together with

the lower part of the surrounding calyptra, x 200.

5. Longitudinal section of a young fruit-rudiment, x 500.

6. Longitudinal section of a somewhat dwarfish fruit-rudiment at the com-

mencement of the differentiation of the capsule-wall and contents,
x 300.

7. Lower end of the stalk of a half-ripe fruit, X 200.

15. Two lobes of a somewhat developed leaf spread out, X 200.

16. Ripe spore, X 200.

17 — 24. Different states of the development of the flat pro-embryo, 20, 21,

and 22 are lateral views, x 200.
25". The terminal bud of the first leafy axis, x 300.
256, 26. The first leafy axis proceeding from the pro-embryo, x 300.

EXPLANATION OF THE FIGURES. 453

Eigs. 8 — 14, 27 — 42. Frullania dilatata.

FIG.

8", *, c. Three successive stages of development of superior leaves. In,
fig. 8C the under lobe of the leaf is shown as a single row of cells.
8" and 86 are x 300, 8C is X 150.

0. Leaf bud seen from above, X 200.

10. Leaf bud seen from the upper side, X 200.

11. A young inferior leaf, x 300.

12. Two lobes of a youug superior leaf spread out, X 200.

13. 14. Upper lobes of older superior leaves, x 200.

27. Ripe spore just set free, X 300.

28, 29. Spores at the beginning of germination, having become bicellular,

X 300.

30 — 36. Outlines of the cells of germinating spores ; in figs. 30 — 33 the outer
spore-membrane is shown ; 36* is the germ-plant shown in fig. 36 turned
round 90°.

37, 38. Germ-plants more developed seen from the outside.

39. A very young, 40 a more developed, 41 a half-ripe, 42 a ripe ruptured
antheridium ; near the latter are some escaped mother-cells of sperma-
tozoa, from some of which the spermatoza have already escaped, x 400.

PLATE XII.

FRULLANIA DILATATA.

1. Two young archegonia surrounded by the rudiment of the perianth, x 400.

2. Longitudinal section of a perianth seen from the outside, X 400.

3. Longitudinal section of an inflorescence containing two half developed and

one impregnated archegonium, X 400.

4. Longitudinal section of the lower part of an impregnated archegonium,

with a seven-celled fruit-rudiment, X 400.

5. Longitudinal section of a more developed fruit-rudiment, with the arche-

gonium becoming transformed into the calyptra, x 400.

6. 7. Young fruit-rudiments, detached. 6 and 64, 7 and 7b, are the same pre-

parations, 6 and 7 being the figures obtained by adjusting the microscope
to the longitudinal axis, and 64 and 7 b by adjusting it to the outer sur-
face, X 400.

8. Longitudinal section of a more developed fruit, at the time of the differ-

entiation of the capsule-wall and contents, x 300.

9. Longitudinal section of a half-ripe fruit, x 300.

10. Spore-mother-cell with four protrusions (one turned away from the ob-
server) of the membrane, taken from a similarly developed capsule,
x 300.

454 EXPLANATION OF THE FIGURES.

PLATE XIII.

KICCIA GLAXJCA.
FIG.

1. Germ-plant (from a shady habitat) to which the spore is still attached,

x 200.

2. Developed germ-plants from the same locality, x 20.

3. Perfect shoot seen from below, x 8.

4. A young shoot in the bud seen from above, X 30.

4*. Fragment of a capillary root of the median line of a perfect shoot. The
inner wall is furnished with prominent points, x 200.

5. Three-celled rudiment of antheridium not yet grown over by an annular

wall, X 200.

6. Rudiment of an antheridium and part of a longitudinal section of a very

young shoot. The yet undivided mother-cell of the organ is already
grown over by an annular wall, x 300.

7°. Longitudinal section through the fissure of the fore-edge of a perfect
shoot. The upper part of the figure is the lateral surface — through
■u hicli the section has passed — of the deep indentation of the fore-edge ;
the shaded part is the cavity of the lower portion of the latter, in which
the median shoot is developed, x 30.

7*. Longitudinal section of the median shoot bearing two rudiments of anthe-
ridia, one is unicellular and the other is a few-celled oval body sur-
rounded by a wall closing over the apex of the organ, x 400.

8. Longitudinal section of a half-developed antheridium, x 300.

9. Similar section of an almost ripe antheridium, x 200.

10. Mouth of the- sheath of a ripe antheridium, seen from the outside, X 300.

11. Longitudinal section of a youug shoot bearing the rudiment of an arche-

gonium, x 400.

12. Section of a more developed rudiment of an archegonium, x 400.

13. Section of an archegonium whose longitudinal growth is terminating,

X 300.

14. Longitudinal section of a shoot bearing an archegonium ready for impreg-

nation, x 300.

15. An abortive archegonium whose mouth has been laid open by a longitu-

dinal section through the shoot, x 300.

16. Section of an impregnated archegonium with a fruit-rudiment still unicel-

lular.

16*. Lower part of a section of an archegonium lately impregnated with a three-
celled fruit-rudiment, X 200.

17. 18. Longitudinal sections of an archegonium with more fully developed

fruit-rudiments, X 300.

19. Longitudinal section of a young capsule enclosed by the calyptra, x 200.

EXPLANATION OF THE FIGURES. 455

PLATE XIV.

KIELLA REUTERI. — Mont.
FIG.

1 and 2. Germ-plants with spore attached, x 150.

3. A plant produced by the multiplication of a cell of a leaf separated mecha-

nically from an older individual, x 130.

4. Adventitious shoot of an older plant, X 150.

5. Full-grown shoots (cultivated, more slender than in the natural state) ;

the older part of the plant is dead, X 5.

6. Another similar shoot, x 20.

7". The end of the shoot a of the latter, x 200.

8. Terminal bud of a strong shoot after the removal of the older leaves,

X 200. The leaves and the upper layer of cells of the massive portion
of the stem — which latter, as far as the drawing extends, consists of only
two layers of cells — are shown in dark lines above the outlines of the
membranous wing and the second cellular layer of the stem.

9. Longitudinal section of a terminal bud perpendicular to the surface of the

stem, x 200.

10. Terminal bud after the removal of all leaves. Two antheridia are being
formed, the one sunk half down, the other deep down into the duplica-
tions of the margin of the wing, x 150.

10. Young unicellular antheridium with adjoining tissue, laid bare by a sec-
tion parallel to the surface of the wing of the stem, x 150.

12. Longitudinal section of a half-ripe antheridium, x 150.

13. Section through a portion of a fertile shoot which has laid bare an arche-

gonium recently impregnated, and has grazed a lateral axis bearing
antheridia, X 100.

14a. Unimpregnated archegonium with its apex still closed, X 250.
14*. Archegonium ready for impregnation, X 250.

15. Longitudinal section of a recently impregnated archegonium, x 250.

16. Young calyptra just visible through its veil, X 25.

17. Longitudinal section of a calyptra with sporangium (a younger state than

Fig. 16), x 200.

18. Longitudinal section of the same when half ripe, the section not having

passed through the mouth, x 100.

19°. Mother-cell with four spores enclosed in special-mother-cells, x 250.
19*. Rudimentary elater from the same sporangium, x 250.

PLATE XV.

Figs. 1 — 18. Marchantia polymorpha.

1. Longitudinal section perpendicular to the surface of a shoot bearing a very

young bud-receptacle, x 50.

1*. The bud-receptacle of the last figure cut through, x 200.

2. Young bud, x 400.

456 EXPLANATION OF THE FIGURES.

FIG.

3, 4. Longitudinal moieties of more developed buds, seen from the surface,

X 300.
5. Half of the fore-edge of a more advanced bulbil, X 300.

7. Bud, whose upper part is beginning to widen, seen from the surface, X 50.

8. The cells of an indentation of a lateral margin of the latter bud, x 300.

9. Bud which has rooted and is beginning to sprout, x 15.

10. Longitudinal section through a shoot bearing the rudiment of a fruit (be-

ginning of April), X 50.

11. Head of young fruit from below (end of May), X 100.

12. More advanced fruit in longitudinal section, X 100.

13. 14. Longitudinal section of impregnated archegonia, x 300.

15. Impregnated archegonium, enclosing a four-celled fruit-rudiment, and

which together with its special covering has been laid open by a longi-
tudinal section grazing the fruit-rudiment.

16. Margin of a growing disk of antheridia (end of November) in longitudinal

section, X 300.

17. Transverse section of the stem of a developed antheridial disk, x 100.

Figs. 18 — 20. Lunularia vulgaris.

18. Longitudinal section perpendicular to the surface, of a very young shoot,

X 300.

19. Similar section of the end of a young shoot bearing the rudiment of a bud-

receptacle.

20. End of a shoot, x 5.

Pigs. 21 — 28. Targionia hypophylla.

21. Longitudinal section, perpendicular to the surface, through a shoot whose

fore-end bears archegonia, enclosed by the rudiment of the veil, X 100.

22. Similar section of a recently impregnated archegonium, x 300.

23. Longitudinal section of an archegonium enclosing a multi-cellular fruit-

rudiment, x 300.

24. Young fruit-rudiment detached, 24* is the same turned 90° round its longi-

tudinal axis, x 300.

25. Longitudinal section of a more developed fruit-rudiment detached, x 500.

26. Similar section of a more developed fruit-rudiment, X 300.

27. Spore-mother-cell still exhibiting its primary nucleus, x 400.

28. Spore-mother-cell in which the four secondary nuclei have been produced,

and having projecting ridges upon the inner surface of the cell-mem-
brane, x 400.

29. Young elater from the same fruit as that which produced the mother-cell

shown in fig. 27, X 400.

30. Young elater from the fruit which produced the spore-mother-coll shown in

fig. 28, X 400.

EXPLANATION OF THE FIGURES, 457

PLATE XVI.
Figs. 1 — 13. Fegatella conica.

FIG.

1. Section parallel to the surface of a shoot formed in autumn and destined

for development in the following spring, X 30.

2. One of the side shoots of this shoot, X 300.

3. Longitudinal section perpendicular to the surface of a similar young shoot,

X 300.

4. Stomata, in process of development, X 300.

5. Rudiment of a fruit-head (beginning of February), in longitudinal section,

X 300.

6. Young fruit-head from below, x 100.

7. Fruit-head at that stage of development when the archegonia are ready for

impregnation, X 50.

8. Young fruit-rudiment with the calyptra enclosing it, and the adjoining por-

tions of the fruit-head, in longitudinal section, X 200.

9. Five-celled fruit rudiment, detached, X 400.

10. More developed fruit rudiment in longitudinal section, X 300.

11, 12. 11 a very young, 12 a somewhat more developed leaf, x 300.

13. Outline of a half- developed leaf, x 30.

Figs. 14 — 20. Rehoidllia hemispherica.

14. Longitudinal section perpendicular to the surface through the very young

rudiment of a shoot. X 300.

15. Outer aspect of the same preparation, after it has been laid upon the sec-

tional surface passing through the longitudinal axis of the shoot. The
rudiments of two leaves are seen. X 300.

16. A young leaf, x 300.

17. Longitudinal section perpendicular to the surface of a fertile shoot. On

the right is a fruit-head ; the section has passed through two unimpreg-
nated archegonia and four scales. Stomate-formation is just com-
mencing in the covering cells of the air-cavities of the fruit-head.
Further back is a cushion of antheridia, cut through. The outlines of
the cells only are drawn, and the contents of the antheridia omitted.
X 300.
IS. An impregnated archegonium in longitudinal section. The mother-cell of
the fruit-rudiment is still undivided. X 300.

19. Longitudinal section of an impregnated archegonium, enclosing a more de-

veloped fruit-rudiment. One only of the rows of cells of which the
young fruit-rudiment consists is seen ; the position of the nuclei of the
second is shown by a dotted circle. X 300.

20. One of the sheathing prolongations of the fruit-head which enclose the

fruit, seen from below. The curved neck of the impregnated arche-
gonium is also seen, x 30.

458 EXPLANATION OF THE FIGURES.

PLATE XVII.

Figs. 1 — 8. Sphagnum cymbifolium.

FIG.

1. Longitudinal section of the terminal bud of the median shoot of a full-

grown plant. The section has passed underneath the fifth leaf of the
left side of a lateral shoot. X 150.

2. Longitudinal section of a young innovation, x 600.

3. Terminal bud of a median shoot, detached and seen from the outside,

x 600.

4. Terminal bud of a median shoot with left-handed \ phyllotaxis, seen from

above, X 500.

5. Terminal bud of a median shoot, detached by two transverse sections, of

which one passed close down the apical point of the transverse cell, the
other through the stem close underneath the third-youngest leaf. All
the older leaves are cut through transversely. The leaves from a to /3
" have a right-handed £ arrangement ; from thence upwards the arrangement
is | and left-handed^, x 500.
5J. Diagram.

6. Young lateral bud, seen from the outside, x 500.

7. Longitudinal section of a part of an innovation, taken at the point where the

growth in thickness of the stem ends, X 500.

8. Longitudinal section of one of the longitudinal moieties of a somewhat

lower part of the same innovation, X 200.

9. Sphagnum acutifolium. — Fragment of a longitudinal section of the circum-

ference of the stem of the principal shoot from the lower boundary of
the region where lateral shoots are crowded together. The cells of the
interior of the stem have pitted walls. X "200.
9*. One of these pitted cells, x 600.

PLATE XVIII.

1. A young leaf of Sphagnum acutifolium, seen from the surface, X 400.

2. Fragment of a somewhat more developed leaf of the same species, in whose

cells the third division is beginning, X 400.

3. Fragment of a leaf of Sphagnum cymbifolium in which the cells with, and

those without chlorophyll are entirely differentiated. Several of the
former have divided by transverse septa, X 400.

4. Fragment of a leaf of Sphagnum acutifolium in whose cells, which are

devoid of chlorophyll, the formation of annular and spiral vessels has
commenced. Several of the latter cells have divided by longitudinal
or transverse septa. X 400.

Pigs. 5 — 13. Sphagnum acutifolium.

5. Pro-embryo which has not yet developed any leafy shoots, X 10.

6. A very young pro-embryo, X 200.

EXPLANATION OF THE FIGURES. 459

PIG.

7. An unusually small pro-embryo ; on the left, near the lower angle, the bud

of a leafy shoot is seen. A new pro-embryo has originated at one of
the rows of cells springing from the marginal cells. X 100.

8. Basal fragment of a highly developed pro-embryo to which the spore is still

attached. The smaller longitudinal moiety of the leafy bud, which is
seated very near the cell, has been removed by the section. X 200.

9. Lobe of a pro -embryo, without any processes from the marginal cells, with

a bud attached, x 100.
11, ]2. 11 a very young, 12 a half ripe autheridium, in longitudinal section,
X 300.

13. Ripe spermatozoa, killed by iodine, x 800.

Figs. 14 — 17. Sphagnum cymbifolium.

14, 15. 14 a very young archegonium, 15 archegonium near the period of

opening; in longitudinal section, X 250.

16, 17. Longitudinal sections of the ends of stems in which the rudimentary cells
of a lateral branch have been exposed by the section (see the left side of
both figures ; in fig. 16 underneath the uppermost, in fig. 17 under-
neath the second uppermost leaf). X 150.

18. Schistostega osmundacca.— Portion of a pro-embryo, X 300.

PLATE XIX.

Pigs. 1 — 16. Funaria hygrometrica.

1—4. Sections of antheridia in different stages of development, x 300.
5 — 8. Mouths of unimpregnated archegonia. 6 and 7 the central cell,
X 300. Figures 5 and 6 are young states, figures 7 and 8 more de-
veloped conditions.
9. Young fruit-rudiment in longitudinal section, X 300.

10. The upper end of the same, X 300.

11. Upper part of a growing calyptra, with the upper half of the enclosed fruit-

rudiment : in longitudinal section. The fruit-rudiment which has not
been cut through is shown in an optical longitudinal section. X 300.
11*. The fruit-rudiment out of the same calyptra, detached, turned round 90°,
and in longitudinal section, X 300.

13. Spore-mother-cell after the formation of the two secondary nuclei, X 400.

14. The same; after the formation of the four tertiary neuclei, X 400.

15. The same; after the divisions of its internal cavity into four special mother-

cells, X 400.

16. The same ; after considerable thickening of the walls of the special-mother-

cells and the formation of the spore-membrane, x 400.

17. Longitudinal section of the upper half of the mouth of a recently impreg-

nated archegonium of Dicrannm Jieteromalhcm. Underneath is the primary
cell of the fruit-rudiment detached from the central cell of the arche-
gonium by contact with the dissecting needle. X 300.

18. Bryum cocspiticium. — Rudiment of a lateral bud, detached and seen ob-

liquely from above, x 300.

460 EXPLANATION OF THE FIGURES.

FIG.

19. Racomitrium ericoides. — Fragment of a lateral branch of a pro-embryo

with the attached germ-plant, x 300.

20, 21. Fissidens bryoides. — Longitudinal sections of archegonia, fig. 20 ready

for impregnation, fig. 21 just impregnated, x 300.

22. Young fruit-rudiment of Bryum argenteum detached, x 300.
22*. The same turned round 90°, X 300.

23. Longitudinal section of the vaginula, and of a fragment of the seta, and

the adjoining parts of the shoot of the same species, x 25.

PLATE XX.

PHASCUM CUSPIDATUM.

1. Longitudinal section of a rudiment of an archegonium, x 400.

2. Similar section of a young archegonium, x 400.

3. Upper end of the same, x 600.

4. Longitudinal section of an archegonium, whose apical cell has ceased to

multiply, X 250.

5. Longitudinal section of an archegonium shortly before the rupture of the

apex, x 500.

G. Archegonium whose apex has lately burst, in longitudinal section. The
still globular daughter-cell within the central cell only fills a small por-
tion of the latter, x 250.

7. Accidental transverse section of the place of junction of the neck, and the

ventral portions of an archegonium, x 250.

8. Central cell of the ventral portion of an archegonium which has been

cut longitudinally, in the state of development shown in fig. 6, x 500.

9. Archegonium just impregnated, X 400.

10. Longitudinal sections of the lower part of the neck, and of the upper part

of the ventral portion, of an archegonium, with a two-celled fruit-
rudiment uninjured by the section, X 300.

11. Similar section of an archegonium with a four-celled fruit-rudiment,

X 200.

11*. A fruit-rudiment, detached, X 400.

llc. Perspective view of the course of the cell walls of the same.

12". A four-celled fruit-rudiment, detached, X 400.

12*. The same turned round 90°.

13. Longitudinal sections of an impregnated and abortive archegonium.

X 300.

14. Similar section of a detached fruit-rudiment, x 200.

15. Similar section of a fruit-rudiment with the growing calyptra and vaginula,

X 75.

15*. Outside of the apex of the same fruit-rudiment, x 400.

16. Portion of the contents of an almost ripe antheridium. Each of the poly-

gonal cellules of the interior of the organ encloses the mother-cell of a
spermatozoon, x 600.

EXPLANATION OF THE FIGURES. 461

PLATE XXI.

FIG.

1. Longitudinal section of a fruit-rudiment, X 200.

2°. Section of the apex of a less advanced fruit-rudiment, X 250.

2*. The same turned round 90°, X 250.

3. A younger fruit-rudiment whose lower part is very highly developed, seen

from the outside, x 30.
3*. Upper part of the same in longitudinal section, x '250.

4. Longitudinal section of calyptra ; the outer side of the spindle-shaped fruit-

rudiment is seen, x 60.

5. Longitudinal section of a young fruit, x 200.

6. A portion of the layer of mother-cells and of the adjoining tissue of a fruit

at a similar stage of development. The primordial utricles of the
mother-cells are contracted by having lain in water for a quarter of an
hour. X 500.

7. Section at right angles to the longitudinal axis of a fruit, passing through a

larger portion of the layer of mother-cells, X 150.

8. A spore-mother-cell out of whose bursting membrane the globular distended

primordial utricle is emerging, X 300.

9. Primary mother-cell from the transverse section of a young capsule. The

cell-contents are beginning to become contracted and constricted, indicat-
ing the commencement of the formation of the spore-mother-cells. X 250.

PLATE XXII.

1. Spore-mother-cell whose primordial utricle only partly fills the cavity and

is lying against the wall, x 500.

2. Two primary mother-cells of the second degree, formed by the division of

of a primary mother-cell of the first degree by means of a septum
parallel to the longitudinal axis of the fruit. Each exhibits only one of
the longish ellipsoidal spore-mother-cells enclosed within. One of the
latter cells is beginning to divide. The section is at right angles to the
longitudinal axis of the fruit. X 300.

3. Primary mother-cells, each with two free globular spore-mother-cells, in

which division is about to commence. Direction of the section as in
the last figure, x 300.

4. Longitudinal section through some primary mother-cells of a somewhat

more developed fruit, X 200.

5. Young spore from the same, X 500.

Eigs. 6 — 21. Gymnostomum pgriforme.

0. Longitudinal section through the upper end of a fruit-rudiment whose
apical cell has ceased to multiply in the direction of its length, and
whose expansion in breadth underneath the apex is just beginning.
The top of the specimen was destroyed by the section ; the representa-
tion of the boundaries of the cells at that part is shown hypothetically
by dotted lines, x 400.

462 EXPLANATION OF THE FIGURES.

FIG.

7. Longitudinal section of a very young fruit, whose apophysis is far larger

than the capsule, x 60.

8. A portion of the layer of mother-cells and of the adjoining tissue of a simi-

lar fruit cut through longitudinally, X 300.

9. A similar preparation from a somewhat more developed theca. The con-

tents of the primary mother-cells of the spores and of the adjoining
cells of the columella are also shown. The primordial utricles of the
latter have contracted by lying in water, x 300.

10. A similar preparation from a more advanced capsule, x 300. Here the

nuclei of the cells immediately adjoining the layer of spore-mother-
cells, i. e., of the so-called inner capsule-wall, and the arrangement of
the chlorophyll of the outermost cells of the same are shown. The
chlorophyll in these cells lies closely attached to the free outer wall.

11. Similar preparation from a capsule in which the formation of the spore-

mother- cells within the primary mother-cells is just about to take
place, x 300.

12. 12*. Spore-mother-cells with the enveloping primary mother-cells, x 300.
13—21. Stages of development of the spore-mother-cell, X 600.

13. Young spore-mother-cell with central nucleus and homogeneous granular

mucilaginous fluid contents.

14. The nucleus is pushed near to the wall ; the protoplasm is accumulated

chiefly in the middle point of the cell.

15. This accumulation has divided into two halves.

16. A secondary nucleus appears in each of them.

17. 18. Four tertiary nuclei are seen in the place of the two secondary nuclei.

19. The primary nucleus of the mother-cell has disappeared.

20, 21. Spores fully formed.

PLATE XXIII.

Figs. 1 — 11. Archidium phascoides.

1. Archegonium ready for impregnation, X 250.

2. Archegonium just impregnated, X 400.

3. Fruit with two archegonia which have been some time impregnated, in

longitudinal section, x 200.

4. A young calvptra just ruptured by the swelling fruit, opened laterally,

x 300.

5. Young fruit cut through longitudinally and detached, x 200.

6. The same somewhat more developed. The primary mother-cell of the

spores has fallen out, x 200.

7. The same, with the full number of cells. In the interior is a primary

mother-cell enclosing four mother-cells. The contents of the latter are
omitted in the drawing, x 300.

8. Primary mother-cell, with four mother-cells. The contents of the special

mother-cells have contracted.

9. Mother-cell with four lately formed spores, x 300.

EXPLANATION OF THE FIGURES. 463

FIG.

10. Mother-cell with four spores. The membrane of the foriner is beginning

to dissolve, x 300.

11. Longitudinal section of ripe fruit, X 100.

Figs. 12 — 15. Fissidens taxifolius.

12. Young leaf seen from the surface, X 300.

13 — 15. Cells of a somewhat more developed leaf of the same species, show-
ing different stages of development of the chlorophyll-granules,
X 400.

PLATE XXIV.

1. Germinating spore of Platy cerium alcicorne. The inner spore membrane

has emerged from the ruptured exosporium in the form of a row of
three chlorophyll-bearing cells. The lowest of these cells has already
developed a capillary root. X 400.

2. Young prothallium of Gymnogramma calomela nos, X 25.

3. Young prothallium of Asplenium septentrionale, X 50.

4. A shoot spontaneously detached from an old luxuriant prothallium of

Gymnogramma calomelanos. It has developed a number of antheridia,
X 150.

5. End of the shoot of an old prothatlium of the same species, x 2.

Eigs. 6 — 12, Pteris serrulata.

6. Eore-edge of a developed prothallium, x 150.

7. Longitudinal section perpendicular to the surface, of a fully developed

prothallium. The small papillae below are antheridia,' the longer ones
archegonia. X 75.

8. Longitudinal section of a young antheridium, X 400.

9. Apical aspect of the same. The course of the septa of the central cell is

shown by dotted lines. X 400.

10. Same view of a more developed antheridium, whose central cell is already

divided into sixteen cells, x 400.

11. Side view of an almost ripe antheridium, X 300.

12. Same view of an empty antheridium, X 400.

13,14,15. Spermatozoa of Asplenium septentrionale, killed with iodine. 13 is
X 1200, 14 and 15 are X 300. 13 and 14 are lateral views, and 15 is
seen from above. The mother-cell is still attached to the spermatozoon
in fig. 14.

Figs. 16 — 19. Ceratopteris thalictrokles.

16. Young prothallium with attached spore, and an antheridium, x 150.
17 — 19. Lateral views of young antheridia, X 300.

464 EXPLANATION OF THE FIGURES.

PLATE XXV.

FIG.

1. Aspidium filix-mas. — Longitudinal section of a young archcgonium in

process of formation, X 200.

2. Gymnogramma calomelanos. — Similar section of a slightly more developed

antheridium, x 400.

3. Pleris serrulata. — Archegonium soon after the formation of the germinal

vesicle, x 400.

4. An archegonium of the same fern without the axile cellular row of the neck,

at the same stage of development, x 400.

5. Aspidium filix-mas. — Longitudinal section of a similarly developed arche-

gonium, x 200.

6. Gymnogramma calomelanos. — Transverse section of the neck of an arche-

gonium at the same stage of development, X 200.

7. Further developed archegonium of the same fern shortly before the burst-

ing of the apex, in longitudinal section, x 400.

8. Pleris serrulata. — A similarly developed archegonium, X 400.

9. Central cell of an archegonium of the same fern, it has been grazed by a

longitudinal section, and the germinal vesicle thereby injured, so that it
exhibits folds of the membrane, x 500.

10. Central cell of an archegonium of the same fern seen from above. Tiie

microscope bas been focussed to the upper surface of the cell of one of
the first archegonia of a young prothallium, whose parenchymatal
cushion was still thin, and permitted the passage of much light, x 400.

11. Pleris serrulata. — Portion of a longitudinal section of a prothallium with

two archegonia ; one with the apex just burst, the other nearly ready
to burst, x 400.

PLATE XXVI.

1. Gymnogramma calomelanos. — End of a shoot of a prothallium, x 5.

2. Gymnogramma clirysophylla. — Abnormal archegonium, from a longitudinal

section of an old luxuriant prothallium, x 200.

3. Gymnogramma calomelanos. — Portion of a longitudinal section of an old

luxuriant prothallium, which has a knob-like excrescence, x 50.
3*. Cortical layer and some of the cells of the inner tissue — filled with a mass
of mucilage and oil— of the above knob, X 300.

Figs. 4 — 20. Aspidium filix-mas.

4. Archegonium at the moment of impregnation. In the central cell of the

archegonium — which has been grazed by two longitudinal sections — are
three spermatoza still in motion. The inner mouth of the canal of the
neck has already become closed again by the expansion of the surround-
ing cells, x 300.

5. Longitudinal section of an archegonium shortly after impregnation. The

enlarged impregnated germinal vesicle does not yet quite fill the central
cell, x 300. J f

EXPLANATION OF THE FIGURES. 465

PIG.

6. Longitudinal section of the fragment of a prothallium, showing an impreg-

nated archegonium with a multi-cellular embryo which has been grazed
by the section.
C4. The net of cells of this embryo ; the boundaries of the cells are drawn of
different thicknesses, according to their age.

7, 7*. More advanced states of 6 and 66.

8. The end of the first frond of a more developed embryo, seen from the

surface, X 300.

9, 10, 11. Transverse sections through the stipes of a frond of a one-year-old

seedling — 9, at the base; 10, somewhat higher up; 11, still higher.
X 20.

12. 16, 17. Transverse sections through the stem of a one-year-old seedling.

12, at the base ; 16, iu the middle ; 17, near the top. x 30.

13. Germ-plants after the development of the frond, in longitudinal section.

Between the first and second root of the primary axis of the embryo.
X 20.

14. The top of the stem of a seedling of ten months old, seen from above. On

the left is the rudiment of the youngest and on the right that of the
next oldest frond. The roundish cells, with granular contents, are
either mother-cells, or cells of attachment, of scales. X 200.

15. A ten-months old seedling, in longitudinal section. The protuberance

below on the left is the primary axis of the embryo, x 20.
IS. Basal outline of a young frond of a seedling, and of the scales surrounding
it, X 30.

19. Upper part of the stem of a full-grown plant cut through longitudinally.

The cellular tissue — up to the vascular bundles — of the divided frond is
removed, to show the course of the bundles. Natural size.

20. A mesh of the net of vascular bundles of a similar stem, with the stumps

of the vascular bundles passing from it to the fronds. X 5.

PLATE XXVII.

1, 2. Apical views of the ends of the stem of full-grown plants. Fig. 1 with
a right-handed, fig. 2 with a left-handed, cell-succession. X 200.

3, 4. Longitudinal sections of terminal buds of full-grown plants. Fig. 3
X 200, fig. 4 x 170. In fig. 4, w represents the rudiment of a frond
divided by the section.

5. A frond still rolled up, the scales having been removed, seen from the back,

showing the rudiment of an adventitious bud. Natural size.

6. Lower part of a stipes, whose lamina is already dead ; with an adventitious

bud in process of development. Natural size.

7. The same object, laid bare up to the vascular bundles of the cortical tissue.

Natural size.

8. Longitudinal section of the tip of a root, x 200.

9. Transverse section of the same, passing through the punctum vegetationis

at the height a b of the previous figure, X 300.
10. The middle region of a similar section, somewhat lower down, at the posi-
tion c d of the root in fig. 8, X 300.

30

4GG EXPLANATION OF THE FIGURES.

PLATE XXVIII.

Figs. 1 — 6. Pteris aquilina.

■FIG-

1. Archegonium, with the adjoining cells of the prothallium, in longitudinal

section. The embryo consists of four cells lying in the plane of the sec-
tion. X 300.

2. Longitudinal section of the fore part of the cushion of a prothallium, which,

besides the impregnated archegonium laid bare by the section, and
whose central cell is not quite filled by the rudimentary embryo, bore a
second impregnated archegonium with a far more developed embryo.
Above the cushion of cellular tissue there is seen a portion of the mem-
branous wing of the prothallium, which has been cut by the section, x
150.

3. An unimpregnated archegonium, and one which has been some time im-

pregnated, in a longitudinal section of one and the same prothallium.
X 300.
3*. The cellular net of the embryo of the latter figure. The lines which
answer to the boundaries of the cells of the older generation are much
thickened. The group of cells ac is the rudiment of the principal bud,
and of the first frond ; the group a d is the rudiment of the root.

4. A similar preparation from a more developed prothallium. The cells of

the first degree of the root are here very visible. X 300.

5. Longitudinal section through the cushion of cellular tissue of a prothallium.

The section has passed through an archegonium with a far more deve-
loped embryo. X 300.

Tigs. 7 — 8. Pteris serrulata.

7. Optical transverse section of the central cell of an archegonium just im-
pregnated. The germinal vesicle contains two nuclei. X 300.

S. Longitudinal section of a prothallium, with an embryo in the^state of
development of that of Pteris aquilina, as shown in fig. 5. X 35.

PLATE XXIX.

PTERIS AQUILINA.

Longitudinal section of a young plant which has recently broken through
the archegonium. A portion of the prothallium to which it is
attached is figured. X 150.

Imaginary outline of a more developed germ-plant — B the primary axis,
a the first, r> the second frond ; between the two the position of the
apical cell is indicated ; c the first, E the second, r the third adventi-
tious root.

The fore-edge of the first frond of a germ-plant in the same state of deve-
lopment, seen from the fore-surface, x 100.

EXPLANATION OF THE FIGURES. 467

FIG.

4. Longitudinal section of the end of the bud of the principal axis of the

same, X 400.

5. A further developed germ-plant shown in a longitudinal section through

the median lines of the first two fronds. The first and fourth adventi-
tious roots have been cut by the section.

6. A more developed germ-plant shown in a longitudinal section at right

angles to the former one, the section passing through the second and
third adventitious root-

7. Transverse section of the older portion of the axis of a seedling of a

month old, X 30.

8. 9. Transverse section of the same nearer the apex.

9*. The same at another neighbouring point of the same axis, x 5.
10, 11. Seedling of a year old. Natural size.
12, 13. Transverse section of the stem of the same, taken near the apex, x 5.

14. Transverse section of the third frond of a germ-plant, X 10.

15. The end of a vigorous shoot in November. Natural size. Adjoining the

end of the stem is seen the frond destined for development in the follow-
ing spring. More to the left is seen the lower part of the frond of the
current year, whose lamina has already opened.
1G. Forking stem-end, seen in a section through the longitudinal ridges. The
sheath of vascular bundles of the middle of the stem is laid bare by
the section. Twice the natural size.

PLATE XXX.

PTEEIS AQU1L1NA.

1} ", *, *• A similar shoot in the spring, peeled as far as the cortical vascular
bundle, in order to show its course. Seen from the left, from the right,
and from above. Natural size.

1. d<e- The principal vascular bundles of the shoot, with their ramifications

to the frond of the previous year.

2. Transverse section of astern at the place of insertion of a frond. Natural

size.

3. Transverse section of a stem, X 3.

4. Longitudinal section of the terminal portion of the apex of a frondless stem

of a very old plant, X 15.

5. Apex of a stem bearing a young frond, with the rudiment of an adventitious

bud, seen from above. Natural size.

6. Frond destined for development in the following year, as it appears late in

autumn, after the removal of the scales ; seen in front. Natural size.
6". The rudiment of the lamina of this froud, x 15.

7. 8, 9. Transverse sections of a stipes — fig. 7 close to the stem, figs. 8 and

9 somewhat higher up, X 3.
10. Transverse section of a portion of the lower principal vascular bundle of the
stem-bud, one and a half line backwards from the apex, X 150.

468 EXPLANATION OF THE FIGURES.

FIG.

10*- Transverse section of the same portion of the same vascular bundle, one
line and a half further back. The number of the cells has considerably
diminished during the thickening of the walls of those which remain.
X 150. The vessels are figured as they appear under a moderate
magnifying power, the sections not being very thin.

11. Two vessels and the neighbouring cells of a complete vascular bundle seen

in a very delicate transverse section, x 500.

12. Longitudinal section of the margin of a principal vascular bundle, at

the place where the thickening layers begin to appear in the spiral
vessels, X 500.

PLATE XXXI.

PTERIS AQTJILINA.

1. Similar longitudinal section of a more advanced vascular bundle, in which

the thickening layers of the scalariform vessels are seen, x 200.

2. Apex of the stem seen from above, X 300.

3. Apical aspect of the apical region of the stem exposed by a transverse section

passing through the surrounding cortical substance, which has the form
of a circular wall. The radiating light spots indicate the course of the
cortical vascular bundles which converge towards the punctum vege-
tationis. x 30.
3*. The apical surface of this end of the stem. The apical-cell is seen in the
middle; on the left hand, near (and above) it is the rudiment of the
youngest frond. X 300.

4. Longitudinal section, perpendicular to the horizon of the end of the

stem, X 300.

5. The same in a longitudinal section parallel to the horizon, X 200.

6. Horizontal section of the end of a stem which has passed transversely through

several rudimentary roots ; that shown by the letter a is exactly
in the punctum vegetationis. x 5.
6*. The above rudimentary roots, X 200.

PLATE XXXII.
Figs. 1 — 3. Pleris aquilma.

1. Longitudinal section of the end of a stem. At the vascular bundle, to the

left, is the rudiment of a root laid bare, for its whole length. X 15.
I6. The rudiment of a root just mentioned, x 300.

2. Longitudinal section of the very young frond of a seedling one year and a

half old. Above the scale is the rudiment of a bud. X 250.

3. Longitudinal section of a one-year-old frond of a full-grown plant. A

dormant adventitious bud is laid bare. X 10.
3\ The adventitious bud, x 200.

EXPLANATION OF THE FIGURES. 469

FIG.

4. Apical view of the terminal bud of Aspidium spinulosum, surrounded by the

rudiments of the youngest fronds, X 250.

5. Diagrammatic representation of three divisions of the apical-cell of Aspidium

filix-mas or spinulosum, and of the displacement caused by the change of
form of the apical-cell (see p. 239). The original position of the older
walls is shown by dotted lines, the later ones by continuous lines ; both
are indicated by the same (Arabic) figures. The Roman figures refer to
the cells of the second degree ; II is the oldest, III the intermediate,
IV the youngest, of the latter cells.

C. Diagram of the displacements caused by the next three divisions following
the same rule.

7, 8. Stages of development of the scales of Nephrolepis splendens.

9 — 13. The same in Niphobolus rupestris.

PLATE XXXIII.

Figs. 1 — 6. Aspidium filix-femina.

1. A frond which has been torn off, and kept for a long time in a close, warm

place, and which has produced an adventitious bud at its base. Natural
size.

2. Longitudinal section of a terminal bud, x 250.

3. The apex of the lamina of a half-developed frond seen from above, X 250.

4. Longitudinal section of a young frond, with the rudiment of a root, x 300.

5. The same somewhat more advanced, x 100.

6. Longitudinal section of the apex of a root which has not yet broken

through the tissue of the frond, X 250.

7. Longitudinal section of the upper end of the frond of Struthiopteris ger-

manica, x 30. On the developed frond, to the left, is seen the rudiment
of an adventitious root.

8. The last-mentioned rudiment, x 150.

Figs. 9 — 20. Maraflia circut(efolia.

9. Longitudinal section of the end of a stem, x 10. The small circles dis-
tributed through the parenchyma are gum-passages. An adventitious root
lies deep down in the cortical tissue. Of the youngest of the two visi-
ble fronds there is only a small fragment at the side remaining, to which
the corresponding membranous lateral portion of the stipule is at-
tached.

10. Longitudinal section of an adventitious bud of the base of the stipule,

X 30.

11, 12. Young fronds of different ages seen from above, x 10.

13, 14. Somewhat older fronds, in longitudinal section, x 10.

15. Lateral segment of the same, showing a stipule in process of develop-
ment, x 10.

470 EXPLANATION OF THE FIGURES.

FIG.

16. Transverse section of the place of attachment of a more developed frond.
The circle in the middle shows the place of insertion of the cylindrical
stipes (within it are the vascular bundles) ; the rest of the tissue be-
longs to the stipule.

17, 18. Transverse sections through the stipule and stipes of the same frond,
one and two lines higher up.

19. Longitudinal section of a similarly developed frond. Twice the natural

size.

195. Lateral half of the stipule of the latter frond, after the removal of the
leafy portion.

20. Apical region of a half-developed frond, seen from above, x 100.

PLATE XXXIV.

1. Swollen end of a runner of Nephrolepis midulata, in longitudinal section,

X 20.

2. Perfect and growing tuber of the same plant. Natural size.

3. Shoot of a similar tuber, detached from the latter. It has already pro-

duced two runners.

4. Longitudinal section of the terminal bud of Poly podium vtdgare, x 250.

5. 6. Apical aspect of the tips of the stem of the same fern, x 250.

7. Apical view of the tip of the stem of Polypodium dryopteris.

Pigs. 8 — 12. Platy cerium ctlcicorne.

8. Transverse section of the perfect stem. Natural size.

9. Transverse section of the stem close under the growing terminal bud.

Natural size.

10. Net of vascular bundles of the stem seen from above. Natural size.

11. The same seen from below.

12. Longitudinal section of the bark of a root, x 100.
12*. Some cells of the latter, x 450.

PLATE XXXV.

1. Terminal bud of a very vigorous autumn shoot of Equisetum limosum, x 400.

2. Longitudinal section of the end of the bud of a lateral shoot of Equisetum

arcense, at the beginning of May, X 200.

3. Equisetum limosum. — Apical view of an end of a stem divided by a transverse

section, underneath the third cell from the apex. The edges of contact
of the cells within the stem, underneath the cell of the first degree, are
shown by dotted lines, x 500.

4. Similar terminal bud; the section has passed somewhat lower down; x

200.

5. Transverse section of the stem of Equisetum limosum close under the apex,

X 300.

EXPLANATION OF THE FIGURES. 471

FIG.

6. Lateral view of a terminal bud of the same species laid bare by two parallel

lomritudinal sections, X 30.

7. Terminal bud of the same Equisetum exposed by thin parallel sections

perpendicular to the axis of the stem. The youngest and the second
youngest leaf are uninjured ; the rest are cut transversely. X 20.

8. Portion of a very young leaf of Equisetum limosum exposed by transverse

section through the end of the stem, seen from above, x 300.

9. Lateral view of two tips of a somewhat older leaf; the one to the right is

about to fork, x 300.

10. Mother-cell of one of the whorled adventitious shoots of Equisetum limosum

exposed by two parallel longitudinal sections through the young stem-end.
X 300.

11. Longitudinal section of a similar shoot in a somewhat later stage of de-

velopment, x 300.

12. Longitudinal section of a portion of an older internode, with a fragment of

the leaves belonging to it. The section has laid open the cavity of the
base of the leaf, in which an adventitious bud is concealed. X 60.

13. Part of a longitudinal section of a young internode of Equisetum pratense.

In the cells of one longitudinal row annular vessels are formed. The
transverse septa of these cells are still present. X 300.

PLATE XXXVI.

1. Left side of a delicate longitudinal section of the apex of a growing

delicate shoot of Equisetum variegatum, X 300.

2. A portion of the seventh iuternode (reckoning downwards from the apex),

from the same longitudinal section.

3. Longitudinal section of the rudiment of the fruit of Equisetum limosum at

the beginning of April, x 30.

4. 5. Longitudinal section of the youngest sporangium-receptacle from the

same specimen, X 200.
0. Half-developed fruit (at the end of October) of Equisetum arvense, in

longitudinal section, X 50.
7, 8, 9. Stages of development of the sporangia of the same species, all in

longitudinal section, X 300.

10. Transverse section of a young sporangium of the same species, x 300.

11. Group of young primary mother-cells of the spores of Equisetum variegatum;

two of them are about to divide, X 300.

12. Pour spore-mother-cells of Eq. limosum adherent to one another, more

developed, X 300.

13. Half of a young receptacle, with sporangium of the same species, x 150.

PLATE XXXVII.

Figs. 1 — 18, 21, 24. Equisetum limosum.

1. Tree spore-mother-cell, x 400.

2. Spore-mother-cell, whose primary central nucleus has dissolved, x 300.

472 EXPLANATION OF THE FIGURES.

FIG.

3, 4, 5. Spore-mother-cells, with two secondary nuclei, between winch a
flattened agglomeration of granules is gradually being formed. Pig. 3
is x 300, figs. 4 and 5 are x 400.

6. Mother-cells, with four tertiary nuclei, arranged in the angles of a tetra-

hedron, x 450.

7, 8. Mother-cells divided into four special-mother-cells, X 300.

9. Special-mother-cell divided from its sister-cells, and which has become
globular. A spore is just forming in it. x 300.
10 Special-mother-cell, with the globular spore. Upon the inner wall of the
special mother-cell the first traces of the two wide spiral threads are
visible. X 400.

11. Ripe spore, after the stripping off of the remains of the special-mother-cell

(the elaters), crushed in sulphuric acid, x 400.

12. Commencement of germination ; numerous chlorophyll-granules are visible

in the fluid contents. The central nucleus of the spore has disap-
peared; in the cell two accumulations of granules are seen, each of
which surrounds a secondary nucleus. X 400.

13—18, 21. Differently developed germ-plants, from the beginning to the
middle of June, X 300.

24. Fragment of the margin of an older prothallium (in the middle of July),
with a half-developed and a ripe antheridium, both shown in longi-
tudinal section, x 200.

Tigs. 19, 20, 22, 23, 25 — 37. Equisetum arvense.

19, 20, 22. Germinating spores developed in water, X 300.

23. Somewhat older prothallium, showing the earliest antheridia, X 150.

25. Portion of the contents of a half-ripe antheridium ; small tessellated cells

enclose the ellipsoidal mother-cells of the spermatozoa, x 400.

26. A free mother-cell of spermatozoa, X 300.

27. A mother-cell, showing the spermatozoon, X 300.

28. Spermatozoon crippled by treatment with very diluted, watery solution of

iodine. The stiffened cilia are already visible, whilst the tail still
escapes observation by its undulations. X 500.

29. Spermatozoon quite killed by the same reagent. Its hinder end, already

somewhat swollen, is in such a position as to enclose a globe of
highly refractive matter; this is of rare occurrence. The membrane
ofthe mother-cell is attached to the frontal turns of the thread, x 500.
30 — 33. Spermatozoa killed by tincture of iodine. They are far more con-
tracted than those whose motions have ended spontaneously or have been
terminated gradually by treatment with a very watery solution of iodine.
Great differences are apparent in their size, as appears by the comparison
of spermatozoa, drawn with the same magnifying power, x 500.

35. Longitudinal section of a rudiment of an archegonium, x 300.

36, 37 Similar sections of more developed archegonia; fig. 36 x 200,

fig. 37 X 300.

EXPLANATION OF THE FIGURES. 473

PLATE XXXVIII.

EQUISETUM ARVENSE.
FIG.

1. Longitudinal section of an arcbegonium shortly before the opening of the

apex, x 300.

2. The same immediately after the opening, X 300.

3. Perspective view of an arcbegonium lately opened, shown by means of

two parallel longitudinal sections of the prothallium, x 300.

4. Longitudinal section of an arcbegonium just impregnated, X 300.

5. 7 — 10. Detached embryos in different stages of development, seen in lon-

gitudinal section, x 200.

6. Longitudinal section of an impregnated arcbegonium, with the embryo in

the central cell, x 300.

11. Accidental transverse section of a rudimentary embryo, x 200.

PLATE XXXIX.

1, 2. Longitudinal sections of impregnated archegonia, with embryos ; fig, 1,
before the falling off of the cells of the mouth ; fig. 2, after the same.
X 200.

3. Longitudinal section of a lobe of a prothallium, with two impregnated

archegonia, x 200.

4, 5. Embryos more advanced, seen in the front, so that both the primary and

the secondary axes are in the line of sight, X 200.
6. Longitudinal section of the lower part of a germ-plant, at about, the stage
of development of fig. 3 in the next plate, X 100.

PLATE XL.

1. Lobe of a highly developed prothallium cut through longitudinally. Be-

sides abortive archegonia, the section has exposed an impregnated one
with a considerably developed embryo. X 100.

2. Embryo just breaking through the prothallium, shown in longitudinal

section.

3. Portion of a prothallium with a germ-plant, whose root and first leafy shoot

have recently emerged from the prothallium, x 10.

PLATE XLI.

Eios. 1 — 4. Ophioglosmm vulgattm.

Longitudinal section of a stem at the beginning of December. Above, on
the left, is a rudimentary pair of fronds (about \ inch long), destined for
development iu 1 he following spring. The section is exactly through
the median line of the protuberance of cellular tissue, which is situated
somewhat laterally in front of the latter frond, and which encloses the
younger fronds. X 20.

474 EXPLANATION OF THE FIGURES.

FIG.

2. Longitudinal section through the middle line of the frond destined for

development in the following spring in the bud-region of a similar stem,
x 20.
2*. The terminal bud and the two youngest fronds of the latter specimen,
x 200.

3. Transverse section close above the terminal bud of a similar stem, x 20.
3*. Transverse section through the same stem, i line lower down.

4. Transverse section close above the terminal bud, which is seen through the

opening of the narrow canal leading to it, x 300.

Pigs. 5 — 11. Botri/chium Lunaria.

5. Longitudinal section of a prothallium, X 50. Above, to the right, is an

archegonium ; on the left of this are five autheridia, of which three are

empty.
G. Longitudinal section of autheridia shortly before opening, X 300.
7. Hinder end of a prothallium, with remains of the spore-membrane, X 300.
8 — 10. Germ-plants with adherent prothallia, x 6. Figs. 8 and 9 seen from

the side, fig. 10 from above ; p, prothallium ; a, the end of the primary

axis of the germ-plant.
10*. The germ-plant. Fig. 10, longitudinal section, with adherent prothallia;

ff, the end of the bud of the principal axis of the germ-plant, x 30.

PLATE XLII.

1. Germ-plant with prothallium seen from above, X 6.

1*. The same cut through longitudinally in the direction from a to p.

2, 3. Abortive germ-plants whose prothallia are already dead, x 6.

4, 5, 6. Normally developed germ-plants, about one year old. Natural size.

7, 8. Germ-plants whose second frond already projects out of the lower first
frond, x 2.

9. The same cut through longitudinally, X 20. The first frond has already
died down to a hardly perceptible membranous border. In the stipule-
like second frond the rudiments of the third and fourth lie concealed.

10. A plant dug up in September, 1854, cut through parallel to the surface of

the frond destined for development in the following spring. Natural
size.
10*. The lower part of this specimen, x 20.

10". Terminal bud of this specimen, in a position turned from the right to the
left, x 300.

11. Section of the bud of a plant in full growth at the beginning of June. The

rudiment of the fertile frond is already visible close by the enclosed frond
destined for development in the next year but one.

EXPLANATION OF THE FIGURES. 475

PLATE XLIII.

riLULAKIA GLOBULIFERA.
FIG.

1. Longitudinal section of a ripe large spore.

2. Longitudinal section of the upper part of a large spore at the first com-

mencement of germination, x 300.

3. Lateral view of a very young prothallium, X 400.
3*. The same cut through longitudinally, X 400.

4. Longitudinal section of a germinating spore, with the prothallium still con-

cealed between the lobes of the outer spore-membrane, X 50.

5. Longitudinal section of a young prothallium, x 300.

6. A small spore whose inner membrane has burst and from the fissures in

which the motber-cells of spermatozoa are emerging ; from some of the
latter the spermatozoa are escaping, x 600.
66, 6C, 6d. Spermatozoa in different positions ; 6*, one which has just made its
way out of the mother-cell, X 500.

7. The upper part of a germinating inner spore seen from the outside, with

some spermatozoa, X 150.

8. Longitudinal section of a prothallium ready for impregnation, X 500.

9. Prothallium ready for impregnation (or just impregnated ?) in longitudinal

section. The contents of some of the cells of the covering layer, and also
the layer of a portion of the outer spore-membrane, is shown. X 400.
10, 11. Longitudinal sections of prothallia just impregnated, enclosing rudi-
ments of embryos, X 300.

12. Prothallium with a more developed embryo, in longitudinal section, X 300.

13. Embryo of a similar prothallium, x 300.

14. Prothallium with an embryo which is beginning to develope the first frond,

in longitudinal section, X 300.

15. Embryo enclosed by the prothallium iu the act of forming the first frond and

the first root, X 300.

16. Longitudinal section of an abortive prothallium, X 300.

PLATE XLIV.
Figs. 1 — 7. Pilularia globulifera.

1. Longitudinal section of a prothallium containing an embryo about to burst

forth, X 50.

2. Longitudinal section of a spore and germ-plant whose first frond has

broken through the prothallium.
26. Bud-end of the latter germ plant, x 300.
2°. Root-end of the latter germ-plant, x 300.

3. Longitudinal section of a young macrosporangium, x 300.

4. Central cell of the latter, rather more developed, x 300.

476 EXPLANATION OF THE FIGURES.

fig.

5. Two spore-mother-cells, and some of the small mucilaginous cells out of

the inner cavity of a sporangium destined to form a large spore, X 300.

6. One of the young, large spores, with a set of four abortive special-mother-

cells, from a similar sporangium, X 300.

7. A similar sporangium, cut through longitudinally, at the same stage

of development, X 200.

Tigs. 8 — 14. Pilularia rainuta.

8. Longitudinal section of a very young fruit, x 100.

9. An almost ripe fruit, cut transversely close above the lowest sporangia,

x 10.

10. Mother-cell of large spores divided into four special-mother-cells, X 400.

11 — 14. Stages of development of large spores ; by the side of figs. Hand 12
abortive mother- cells from the same sporangia are drawn. Fig. Jl is
X 300, fig. 2 is X 150, and figs. 13 and 14 are x 250.

Pigs. 15 — 24. Marsilea pubescens.

15. Outlines of a large spore just escaped from the opening fruit, in longitudi-

nal section.

16. Apex of the same (the gelatinous covering in this and the following figures

is not shown). The primary spore-membrane and the lenticular cell
occupying its apex have been carefully drawn out from the introversion
of the inner layer of the exosporium. X 300.

17. Commencement of germination. In each lenticular cell two globular nuclei

are seen in the place of the primary one. X 300.

18. Bicellular rudiment of a prothallium, laid bare by means of two parallel

longitudinal sections through the spore. The primordial utricles of the
cells are contracted by the action of a concentrated solution of caustic
potash, x 400.

19. Lateral view of a four-celled rudimeut of a prothallium, x 400.
20 — 21. Lateral view of a more developed prothallium, x 300.

22. Prothallium ready for impregnation, in longitudinal section, x 300.

23. Half-developed prothallium, seen from above, x 300.

24. The same from below, x 300.

Pigs. 25 — 32. Salvinia nutans.

25. Microsporangium cut transversely ; the antheridia (microspores which have

shed their outer membranes) are falling out, X 200.

26. A single microspore less developed, x 200.

27 — 28. Cellular bodies (antheridia) squeezed out of the sporangia with small
spores in the middle of March, X 300.

29, 30. Riper antheridia already half emptied, x 300.

31. Spermatozoon with attached mother-cell, X 500.

32. Spermatozoon killed by iodine, X 500.

EXPLANATION OF THE FIGURES. 477

PLATE XLV.

SALVINIA. NATAXS.
PIG.

1. Longitudinal section of a large spore at the commencement of germination,

X 30.

2. A fragment of the exosporium of a microspore, in longitudinal section,

X 300. Three layers are distinguishable. A thin inner layer, a thicker
middle layer, and a very thick, apparently cellular, outer layer.

3. A very young prothallium, detached, with a fragment of the inner spore-

membrane adhering to it, x 200.

4. The same, the longitudinal section passing through the entire spore,

X 200.

5. A more advanced prothallium, in which the first archegonium is developed;

in longitudinal section, x 200.

6 — 7- Longitudinal section of unimpregnated archegonia, in which germinal
vesicles are visible, x 300.

8. Transverse section of an unimpregnated archegonium with two terminal

vesicles. The observer is looking into it from below, and in the middle
of the figure the interior of I he mouth of the canal is seen.

9. Fragment of a prothallium cut through longitudinally, in which archegonia

are visible, one unimpregnated and the other just impregnated, x 300.

10. Longitudinal section of the angle of a prothallium, exhibiting an archego-

nium with an unusually long canal, X 300.

11. Three-celled embryo, entirely filling the central cell of its archegonium.

The position of the mouth of the canal is shown by two lines, x 200.

12. An impregnated archegonium, with an abnormally large central cell, a small

part of the latter only being filled by the few-celled embryo, x 200.

13. An impregnated archegonium enclosing an eight-celled embryo, X 300.

14 A 16-celled embryo detached, a from the outside, laterally, b in longitudinal
section, c seen from behind.

15. A somewhat more developed embryo detached, a from above, b from the

side, c also from the side turned round 90°. x 20.

16, 17, 18. More advanced embryos ; figs. 16 and 18 entirelv, and fig. 17 half

detached. Pigs. 16 and 18 are X 200, and fig. 17 is x 300.

19. Embryo enclosed by the prothallium, x 300.

20. Detached embryo seen from the front surface, x 200.

21. Embryo enclosed by the prothallium. The first leaf is beginning to develope

itself above, x 300.

22. Spores with prothallium and embryo somewhat more advanced, in longitu-

dinal section, x 50.

23. A similar embryo, x 200.

21. A similar embryo detached and seen from the front surface of the first leaf,
at the lower margin of which the end of the principal axis is clearly
visible, X 200.

25". An embryo more advanced, seen half in front. Near the first leaf a the
principal axis b — which is already once forked and is in the act of
forking again — is visible ; behind it is the hinder end of the germ-plant c.

478 EXPLANATION OF THE FIGURES.

FIG.

jz' ■*?■ " /Iew" , [ The same letters represent the same parts.

25°. View from above. ) l l

26. A germinating spore, whose prothallium is broken through by the first leaf

(not by the elongating axis of the embryo), X 50.

27. Spore with prothallium and embryo after the elongation of the axis of the

latter, X SO.
27*. The terminal bud of the latter embryo, x 300.

28. A more developed germ-plant, with spore attached, in longitudinal section,

X 150.

29. Terminal bud of a similarly developed germ-plant, seen from above. Near the

third leaf, which is still closely folded (to the left in the figure) is seen the
end of the principal axis ; underneath it are three of its delicate forks,
which are developed into the so-called roots.

PLATE XLVI.

ISOETES LACUSTB.IS.*

1. A large spore, a fortnight after sowing, and after soaking for several hours

in glycerine, seen from above. The first-formed cells of the prothallium
appear spread over the inner wall.

2. Longitudinal section of prothallium four weeks after sowing, x 40.

3. Portion of the apex of a prothallium cut through longitudinally, with two

archegonia still in process of development, x 300.

4. Archegonia ready for the separation of the angles of contact of the upper

three double pairs of cells, in longitudinal section, x 300.

5. 6. Longitudinal sections of archegonia ready for impregnation, x 300.

7. A ripe microspore seen from above (perpendicular to kthe transverse dia-

meter) x 500.

8. Lateral view of a microspore four weeks after sowing. The mother-cells

of the spermatozoa are formed, x 500.

9. Microspore three weeks after sowing. By rolling the spore under the cover-

ing glass the exosporium has burst and is pushed on one side. The
mother-cells of the spermatozoa entirely fill the inner cavity of the spore.
X 500.
10. A small spore, burst, four weeks after sowing. It has already sent forth
several spermatozoa ; one of them, still partly enclosed by the mother-
cell, is seen within the latter in active motion.

* Plates XLVI to LIII relate to Isoetes lacustris, and the letters a, b, &c,
have the following significations :

a Archegonium. ac Central cell, ao Mouth of the same. r/.rEnd of the primary
axis of the embryo, cb Camium. ct Back of the stem, e Embryo, fr Leaves ;
//•' the first,//-2 the second, leaf of the germ-plant, and so forth, fv Vascular
bundle. In some cases the vascular bundles passing to the leaves are merely
represented by//-1 &c, and those passing to the roots by r1, r2, &c. (so also in
fig. \b of PI. XLIX). g Terminal bud ; gc the apical cell of the latter. / Woody
mass; Isp the upper, and /;/the lower, portion of the latter. Ig The supple-
mentary shoot of the fore-side of the leaf covering the base of the scale, r Root.
re The cell of the first degree of the root, v Sheath of the base of the root.

EXPLANATION OF THE FIGURES. 479

fig.

11. A spermatozoon enclosed by its mother-cell, set free by the crushing of a

spore.

12. Spermatozoon still partly sticking in the mother-cell, killed by iodine.

13 — 15. Free spermatozoa in motion. In fig. 14 the spermatozoon drags along
a small vesicle at the thin end.

16, 17. Spermatozoa killed by iodine.

IS, 19. Archegonia, just impregnated, cut through longitudinally, with two-
celled rudiments of embryos. Seen from the narrow side, x 400.

20. A similar preparation ; in the lower cell of the embryo-rudiment division is

commencing by the appearance of two nuclei, x 400.

21. The apex of a prothallium cut through longitudinally, with one abortive and

one impregnated arciiegonium, which latter encloses the four-celled
rudiment of an embryo, X 300.

22. The last-mentioned embryo detached, and seen from the hinder surface.

The line a b is parallel to the section through the impregnated arciie-
gonium.

23. An impregnated arciiegonium laid open by a longitudinal section parallel to

the front surface of the enclosed embryo.

24. Longitudinal section of an embryo; the number of its ceils is less than in

the preceding figure, but the characteristic extension of the apical cells
of the primary axis has already commenced.

PLATE XLVII.

ISOETES LACUSTRIS.

1. A more advanced embryo, cut through longitudinally, X 300.

2. Longitudinal section of a still more advanced embryo, x 200.

3. Longitudinal section of a germ-plant three months old. The apices of the

first and second fronds and of the first root are omitted in the figure.
X 200.

PLATE XL VIII.

ISOETES LACUSTRIS.

1. Lateral view of a six-months-old germ-plant, x 3.

2. Longitudinal section at right angles to the larger trausverse axis of the

stem of a four-months-old germ-plant, x 200.

3. Longitudinal section of the stem at right angles to the lateral surfaces of

the woody mass of a germ-plant about eight months old, x 200.

4. Transverse section of a one-year-old plant at the height of the terminal bud,

x 30.

5. Transverse section of a two-year-old plant at the place of junction of the

upper and lower portions of the woody mass, x 10.

6. Transverse section of an abnormal, three-furrowed, about six-years-old, stem

of Isoetes lacuslris at the same place of junction. Natural size.

7. The middle part of the same preparation, x 30.

8. The terminal bud of the same individual seen from above, X 300.

430 EXPLANATION OF THE FIGURES.

PLATE XLIX.

ISOETES LACUSTRIS.
FIG.

1. Longitudinal section at right angles to the furrow of the stem of a ten-

montlis-old plant, X 30.

P. Woody mass and terminal bud of the same, X 300.

2. Transverse section of the middle of the stem of a plant about eight years

old. The principal portion of the bark and the two side lobes are
omitted, x 20.

3. Rudiment of a scale seen from the surface, x 200.

4. The same more developed.

5. A perfect scale, X 6.

PLATE L.

ISOETES LACUSTK.IS.

1. The terminal bud and the upper portion of the woody mass of the stem

shewn in PI. XLIX, fig. 1, x 300.

2. The same parts of a stem cut through at right angles to the indentation,

X 250.

PLATE LI.

ISOETES LACUSTRIS.

1. Longitudinal section through the furrows of the stem of a plant ei°ht

years old, x 30.

2. Similar section of the lateral surface of the middle region of the woody

mass of an older plant, together with a portion of the cambium. One
of the cells of the latter — separated from the next wood-cells by three
cambial cells— is beginning to become liquefied, x 250.

3. Longitudinal section of a fragment of a vascular bundle from the older

part of the bark, x 250.

4. Transverse section near the woody mass of a vascular bundle running to

an older frond, x 250.

5. Terminal bud of an eight-years-old plant seen from above, X 200.

PLATE LIL

ISOETES LACUSTKIS.

I. Longitudinal section of the stem (at right angles to its furrow) of a six-
years-old plant, X 20.

EXPLANATION OF THE FIGURES. 481

FIG.

2. Similar section of the apex of a root in which forking has commenced a

short time previously, x 400.

3. Half of a forked root in longitudinal section, x 100.

4. Transverse section of a root-tip, x 400.

5. Transverse section of the forking tip of a root, X 400.

6. Fragment of the lower part of the woody mass of an older plant cut through

longitudinally in the direction of its larger transverse axis (part of the
preparation figured in PI. XLIX, fig. 1), x 200.

7. Young frond of an older plant seen from the front, x 300.

8. Similar view of a somewhat more developed frond, X 300.

PLATE LIII.
Figs. 1 — 19. Isoetes lacustris.

1. Longitudinal section of a young fertile frond, X 300.

2, 3. The lower portion of the front surface of a somewhat more developed

fertile frond in longitudinal section, X 300.

4. The lower end of a young fruit cut through longitudinally (according to its

position it is destined to produce microspores), X 300.

5. Longitudinal section of the base of a frond, which bears a half- ripe micro-

sporangium, x 20.

6. 7. Sets of four adherent spore-mother-cells, X 400.

8 — 17. Stages of development of the mother-cell of microspores.

8. The mother-cell filled with homogeneous granular protoplasm, in which the

central nucleus floats freely, X 400.

9. Accumulations of more firm mucilage — the rudiments of the second nu-

clei are forming at the two poles of the globular nucleus, X 500.

10. After the absorption of the primary nucleus and the formation of the

secondary ones the primordial utricle of the mother-cell becomes con-
tracted, preparatory to its division, X 400.

11. The secondary nuclei are in the act of dissolution, before the division of

the cavity of the mother-cell, X 400.

12. A mother-cell divided into two halves by a septum through its equator,

X 400.

13. 14. Mother-cells, each with four free tertiary nuclei ; those in fig. 13 are in

one plane, those in fig. 14 at the angles of a tetrahedron, X 400.

15. Four special-mother-cells united by the mother-cell ; produced by the re-

peated division of the two halves of the mother-cell (the special mother-
cells of the first degree). The septa dividing the latter have different
inclinations, X 400.

16. A similar preparation. The four special-mother-cells are lying in the same

plane, X 400.

17. Set of special-mother-cells arranged decussately in the last stage of for-

mation, immediately before their individualisation. The innermost
layer of the much thickened cell-membrane of the special mother-cells is
far more highly refractive than the already swollen outer layers. Treat-
ment with tincture of iodine has contracted the primordial utricles of
the cells. X 400.

31

482 EXPLANATION OF THE FIGURES.

BIG.

18. Young microspores enclosed by the special-inother-cells, x 300.

19. Half-ripe microspores after the absorption of the special-mother-cells,

X 300.

Figs. 20, 21. Tsoeles tenuissima.

20. Transverse section of the stem of Isoetes tenuissima at the height of the

lower portion of the woody mass of that species, x 20.

21. Longitudinal section of a stem of the same species, X 20.

Fig. 22. Isoetes setacea.

22. Terminal bud of Isoetes setacea seen from above, x 300.

Fig. 23. Isoetes tenuissima.

23. Longitudinal section of a young root enclosed by the cortical parenchyma,

together with a portion of the downward-growing wood and of the cam-
bium adjoining the latter. The contents of the cell of the first degree
and of the upwardly directed daughter-cells of the latter are shown.
X 300.

PLATE LIV.

Figs. 1 — 2. Selaginella helvetica.

1. Young fruit in longitudinal section, x 30.

2. Same section of a very young sporangium, x 300.

Figs. 3 — 12. Selaginella hortensis, Mett.

3. Longitudinal section of! he forking end of a shoot, x 30. The last fork to

the left is a young fruit-spike.

4. Outline of a longitudinal section of a slightly more developed fruit-spike,

X 30.

5. Forking end of a vegetative-shoot, the under side, x 30.

6. End of a vegetative-shoot laid bare by a longitudinal section parallel to the

axis ; seen from the narrow side, x 50.
7". Forked end of a stem, seen from the (wide) upper side, x 80.
7b. The same, seen from above.
7C. The same as 7", x 350.
7d. The same as 7*, x 350.
8.. Half of an end of a shoot which has recently forked (like that shown in fig.

5), in longitudinal section, X 500.

9. End of a shoot at the commencement of forking, in longitudinal section,
X 350.

10. A similar specimen; the fork is somewhat more advanced.

11, ]2. Apices of shoots whose development is almost intermediate between

those shewn in figs. 8 and 9 ; seen from above, X 350.

EXPLANATION OE THE FIGURES. 483

PLATE LV.

SELAGINELLA HOKTENSIS.
FIG.

1, 2. Longitudinal section through that part of the naked end of a young

fruit-spike, at which a sporangium is going to be formed, x 500.
3. A very young sporangium in longitudinal section, x 600.

. 4. A more developed sporangium (destined to form large spores), together
with the leaf above it, cut through longitudinally, X 400.

5. Longitudinal section of a more developed sporangium, x 150.
5*. A portion of the same specimen, x 300.

6. Longitudinal section of a large sporangium, whose mother-cells are begin-

ning to isolate themselves, x 300.

7. Mother-cell of large spores, which has just divided into four special-mother-

cells, surrounded by some of its abortive sister-cells, X 400.
8 — 10. Double pairs of very young large spores, still slightly held together by
the last remains of the dissolved special-mother-cclls. Fig. 8, x 300 ;
figs. 9 and 10, x 500.

11. A young spherical capsule from the outside ; through its walls the four

spores, already of a considerable size, are just visible, X 30.

12. A slightly more developed spherical capsule, opened by a longitudinal sec-

tion, x 50.

i 12v One of the spores of the latter, after long soaking in water, X 300.
| 13. A somewhat more developed large spore, X 300.

14. Transvere section of a more perfect large spore, x 300.

14*. The same spore treated with a solution of caustic potash. The exosporium
is not shown.

15. Half-ripe spore, x 50.

16. Fragment of the wall of a ripe spherical capsule, in longitudinal section>

X 200.

16J. A fragment of the latter wall, seen from the outside. The boundaries of
the larger cells of the second inner layer are just visible through the
small ones of the upper surface, x 300.

17. Fragment of the membrane (the inner and the outer) of a ripe large spore,

cut through longitudinally, X 500.
1 18. Mother-cells of small spores. The lower one still exhibits the primary
central nucleus ; in the upper one to the right it is already dissolved ; in
the upper one to the left are four daughter-nuclei, X 300.

19. A similar mother-cell which has just divided into four special-mother-cells,
X 300.

- 20. A set of four mother-cells arranged tetrahedrically, in each of which a spore

is just forming, x 300.
20*. A similar specimen. The special-mother-cells are placed decussately.

21. First rudiment of a leaf (part of an especially successful longitudinal sec-

tion of a leaf-bud), X 600.

22, 23. The stages of leal'-deveiopment following next after fig. 21, in longitu-

dinal section, x 600.

24, 25. Fore-ends of young leaves seen from the surface, X 300.

484 EXPLANATION OE THE FIGURES.

FIG.

26. Longitudinal section of the apex of a very young stipule, x 400.

27. Same section of a half-developed stipule, X 200.

28. Outline of a slightly more developed stipule, seen from the surface,

x 100.

29. Longitudinal section of the growing apex of a young fruit-brancli, X 350.

Figs. 30, 31. Selaginella spinulosa.

30. Rudiment of a fruit in longitudinal section, x 30.
30*. Young macrospore.

31. Young macrospore.

PLATE LVI.
Figs. 1 — 9, 11 and 12. Selaginella Galeottii ; 10. Selaginella Martensi.

1. End of a shoot bearing only leaves ; seen in longitudinal section of the

wide side (obtained by adjusting the microscope to the longitudinal
axis), x 400.

1*. The same, seen from outside.

lc. The same, seen from outside the narrow side.

2. Oblique view from above of the end of a shoot, x 400.

3. Longitudinal section of terminal bud parallel to the wide side, x 400.

4. Apex of the same seen from above, x 400.

5. Middle of the fore-edge of a young superior leaf, x 300.

6. Tip of a somewhat more developed inferior leaf, x 600.

7. Fragment of the lateral margin of a perfect inferior leaf, X 300.

8. Fragment of the same, nearer to the mid-rib.

9. A very young stipule seen from the surface, x 500.

10. Adventitious shoot of S. Martemi, produced by a fragment of a stem bitten

off by wood-lice, x 10.

11. Half of a longitudinal section of a very vigorous shoot of S. Galeottii,

passing through the median lines of two opposite rows of superior and
inferior leaves (the former are to the right in the figure), x 200.

12. Portion of a similar specimen, x 200.

PLATE LVII.
Figs. 1 — 12. Selaginella Martemi.

1

Mother-cell of large spores, with some of its abortive sister-cells, X 300.

2. A similar mother-cell.

3. Mother-cell of large spores, in which, near the large vanishing primary

nucleus, four daughter-nuclei are formed (three only of the latter are
visible), x 300.

EXPLANATION OF THE FIGURES. 485

FIG.

4. Mother-cell, whose primary nucleus is no longer visible ; the four newly-

formed nuclei lie in one plane, X 300.
4*. The same specimen treated with watery tincture of iodine. The action of
the tincture has separated the four nuclei to some extent from one
another.

5. Mother-cell which has already divided into four special-mother-cells,

x 300.

6. View from above of a half-ripe spore, X 400.

7. Set of four special-mother-cells, each of which contains a similar half-ripe

spore, x 50.
76. A similar special-mother-cell, together with its enclosed spore, isolated by
gentle pressure with the covering glass, x 400.

8. A young large spore with abnormally developed exosporium, X 400.

9. Mother-cell of small spores, divided into four special-mother-cells, iu each

of which a spore has originated, x 300.

10. Set of four special-mother-cells, x 400.

11. Set of two vigorous special-mother-cells, and one abortive one, x 400.

12. Cell with abnormally thick walls from a young capsule, x 300.

.Figs, 13 — 17. Selaginella helvetica.

13. Small spore, five months after sowing. In the internal cavity a large

number of small globular cells has been formed, x 400.

14. A similar spore subjected to gentle pressure. Some of the above cells have

escaped.

15. A similar spore two weeks later, lightly pressed. Each of the escaped

cellules now exhibits a very delicate spiral spermatozon.

16. Large spore shortly after sowing ; in longitudinal section, X 200.

17. Prothallium seen from above, six weeks after sowing, x 300.

Figs. 18 — 23. Selaglnella Martensi.

18. Inner membrane of a large spore just taken from the capsule, removed out

of the exosporium, and viewed perpendicularly to the surface of the
rudiment of the prothallium which is attached to its inner side, X 400.

19. Prothallium six months after sowing, in longitudinal section, X 200.
19*. One of the archegonia of this specimen.

20. Young germ-plant isolated, and cut through longitudinally, x 200.

20*. The spore, from the interior of which this germ-plant was taken. The
distended prothallium enclosing the somewhat developed embryo, pro-
jects far out of the fissures of the apex of the spore-membrane, X 15.

21. An unfolded germ-plant, drawn out of the spore, x 3.

2 P. The prothallium in which it originated, taken out from the exosporium,
x 3.

22. Germ-plant whose first leaves have been removed (the stipules of the latter

are remaining), together with the prothallium freed from the outer spore-
membrane, x 30.

23. A germinating spore, in whose prothallium (which projects from the outer

spore-membrane) two germ-plants have originated, x 5.

48G EXPLANATION Ob' THE FIGURKS.

PLATE LVIIT.

SELAG1NELLA DENTICULATA.

FIG.

1. Longitudinal section of an unimpregnated prothallium, eleven months after

sowing. Several archegonia have been exposed by the section ; in one

of them the spherical cell produced in the central cell is represented,

X 250.
Is. Mouth of an archegonium, seen from above, X 350.
1°. Aperture of an archegonium, where the cells are extended upwards in a

papillate manner ; seen obliquely from above, X 150.

2. Archegonium whose upper cells are still in close connection. The free

spherical cell is not yet formed in the basal cell, X 600.

3. An archegonium just impregnated, laid open by a very successful longitu-

dinal section. The mother-cell of the embryo is divided by a transverse
septum. Unfortunately the specimen was spoilt before the drawing was
finished. A portion of the cellular tissue of the prothallium has been
drawn from recollection. Ineffectual attempts have been made to
obtain another similar specimen, X 000.

4. An impregnated archegonium ; in a longitudinal section, which has exposed

the archegonium in which the rudiment of the embryo lias originated,
and also the course of the proembryo which has formed the suspensor.
X 200.

5. A similar preparation in which the apex of the second axis of the embryo —

which is destined to develope leaves — is turned towards the observer,
X 150.

6. A young embryo detached, with a uni-cellular suspensor (a rare case),

looking upon the wide side of the second axis, X 500.

7. 8. Similar preparations seen from the narrow side, X 500.

9. Prom the wide side ; 10. from the narrow side of the second axis, x 500.

11. Outlines of a prothallium, in which the embryo lies concealed, which latter

has already begun to form its cotyledons, X 30.

12. Longitudinal section of a spore whose embryo has lately broken through

the prothallium ; its leaves are beginning to turn green. The section
has carried away the larger part of one cotyledon, its stipule, and several
leaves of the two rudimentary axes of the third degree of the embryo,
X 30.

PLATE LIX.

1—5. Mother-cells of the pollen of Pinus balsamea, X 300 ; fig. 1, at the end
of March; figs. 2—5, in the first half of April.

6. Pollen-mother- cell of Pinus Larix, divided into six special-mother-cells ;

beginning of March, x 300.

7. Pollen-cell of the same Pinus on the 21st March, after treatment with a

solution of caustic potash. The second nucleus is already formed.

EXPLANATION OF THE FIGURES. 487

FIG.

8. A similar pollen-cell, already divided into two cells, treated with caustic

potash and freed from the exine by rolling under the covering glass,
X 300.

9. Pollen-cell of Pinus Larix, taken from the nucleus of an ovule in the middle

of May. The exine has been stripped off by the swelling of the intine,
X 400.

10. Longitudinal section of an ovule of a cone of Pinus Austriaca (just opened)

at the beginning of June, x 150.

11. Longitudinal section of the nucleus of an ovule of Pinus Mughus from a

cone just in flower, x 300.

12. Embryo-sac of the same species, somewhat later, after the dissolution of

the central nucleus, X 500.

13. Embryo sac of Pinus sylveslris with the neighbouring cells, which are be-

coming detached ; beginning of June, x 500.

14. Longitudinal section of the nucleus of the ovule of a cone of the same

species which has lately flowered (beginning of June). The pollen-tube
has already penetrated rather deeply into the nucleus, x 100.

15. Fragment of a detached embryo-sac of Pinus Austriaca, in the middle of

June. Numerous free secondary nuclei are attached to the inner wall,
X 300.

16. Longitudinal section of the embryo-sac of Pinus sylvestris, filled with cellular

tissue ; end of June, X 300.

17. Ovule and basal portion of the spermophore of Pinus maritima, at the be-

ginning of January of the second year. The walls of the cells of the
very advanced endosperm (E) are much thickened by the addition of
layers of gelatine. Two pollen-grains (P) have emitted tubes for a short
dislance only into the nucleus, x 50.

18. A single cell of the endosperm at the same time, treated with tincture of

iodine. The primordial utricle of the cell is contracted, x 300.

19. A single cell of the endosperm of the same species in the middle of March.

The thickening layers of the cell-wall are already almost dissolved ; only
the primary membrane of the cell is still intact, x 300.

20. Fragment of the membrane of the embryo-sac of Pinus Strobus cut through

longitudinally, with some endosperm-cells loosely attached to the inner
side ; at the beginning of April, x 300.

PLATE LX.

1. Longitudinal section of the embryo-sac of Pinus sylvestris, at the begin-

ning of April of the second year, x 30.

1*. One of the cells of the interior, x 300.

2. Embryo-sac detached, at the beginning of May. A layer of newly-formed

cells has attached itself firmly to the inner side of the hardened mem-
brane of the embryo-sac, which has now entirely displaced the loosened
cells of the surrounding portion of the nucleus, x 30.

2*. Portion of the outer side of the embryo-sac of the latter figure, x 300.
It will be seen that the cells attached to the inner wall of the embryo-
sac are not yet firmly attached to one another at the surfaces of contact
with the latter.

488 EXPLANATION OP THE FIGURES.

FIG.

3. Portion of the membrane of a similar embryo-sac ruptured by gradually

increased pressure. Numerous actively-multiplying cells are forced out
from the fissure of the membrane; the cells also attached to the inner
side of the wall have been detached from it by the pressure, x 200.

4. Longitudinal section of an embryo-sac, for the second time partly filled

with cellular tissue ; in the middle of May of the second year. The
detached membrane of the embryo-sac lies iu folds near it, x 50.

5. Young corpusculum, detached, with some of its neighbouring cells ; at the

end of May. At this time the connection of the individual cells of the
endosperm is still very loose, x 300.

6. Longitudinal section of the upper part of an endosperm; end of May.

Two young corpuscula are visible. The cells covering the apex of the
latter have not yet divided by cross longitudinal septa, x 150.

7. Transverse section through the same part of the less developed endosperm,

on May 27th. The observer is looking from below into four corpuscula
opened by the section. The large nuclei attached to the inner arch of
the apex are visible, x 200.

8. Longitudinal section of a corpusculum at the beginning of June, x 200.

8*. The rosette of cells covering the apex of the corpuscula, seen from above,
x 200.

9. Longitudinal section of a corpusculum, at the top of which the end of a

pollen-tube has just arrived, x 200.

10. The lower end of a corpusculum just impregnated, with the germinal vesicle
pressed into the arch (on the 16th June), x 300.

11 — 13. Stages of development of the pro-embryo (the lower ends of the
longitudinally-divided corpuscula), from the 16th to the 18th June of
the second year, x 300.

PLATE LXL

1. Apical arch of a longitudinally-divided corpusculum of Pinus Abies, L.

{Pinus excelsa, DC), at which the end of a pollen-tube has lately
arrived, and in which several germinal vesicles adhere, of which one has
increased largely in size ; on the 23rd June (1858), x 500.

2. Longitudinal section of the upper part of an endosperm of the same species

at the same time. Two impregnated corpuscula are opened by the
section. In the one to the right the rudiment of a pro-embryo is
pressed into the lower end ; in that to the left a similar rudiment is still
at some distance from tbe base, x 40.

2\ The rudiment of the pro-embryo of this latter corpusculum, x 500.

Pigs. 3 — 11. Pinus Strobus.

3. A germinal vesicle just impregnated ; on the 26th of June, x 200.

4 — 7. A series of stages of development of the pro-embryo, arranged accord-
ing to their state of advancement (from 25th to 28th June). Figs.
4— 6, x 300; fig. 7, X 200.

8. The pro-embryo immediately before dividing into four longitudinal rows of
cells, x 100.

EXPLANATION OF THE FIGURES. 489

FIG.

9, 10. Pro-embryos during the division into their longitudinal rows of cells ;

on the 30th June, x 100.
11. (The middle figure.) — One of the fourth parts of the pro-embryo, at whose
lower end the multiplication in the direction of the thickness has begun,
X 100.

Fig. 11 (left-hand figure) to Fig. 14. Plnus Larix.

11. (Left-hand figure.) — End of a pollen-tube drawn out from the corpus-

culum, which has been just impregnated.
11J. The same object after its apex and the cell hanging to it have been pushed
out.

12. Apex of a pollen-tube, and portion of the cell attached to it, X 400.

13. 14. Longitudinal section of corpuscula just impregnated, X 150.

PLATE LX1I.

Figs. 1 — 8. Pinus Canadensis.

1. The upper part of an endosperm shortly before the arrival of the pollen-

tube at the embryo-sac (on the 7th July of the first year), with two
corpuscula laid open by the section, X 200.

2. Longitudinal section of a corpusculum, into which a pollen-tube has lately

penetrated (beginning of July), X 200.

3. Longitudinal section of an endosperm (middle of July). It exhibits two

corpscula. A pollen-tube has shortly before penetrated to the upper
surface of the left hand one. Against the base of this corpusculum the
four-celled rudiment of the embryo is compressed, x 200.

4. A recently impregnated germinal vesicle (middle of July) confined at the

lower end of the corpusculum, which has been cut through longitudinally,
x 400.
4*. The same specimen treated with an alkaline ley.

5. Longitudinal section of a corpusculum containing a rudimentary pro-

embryo pressed into the base, and another less developed one floating
freely, X 100.

7. A further developed pro-embryo. The walls of the upper cell, which are

are turned towards the corpusculum, are much thickened by the addition
of glassy transparent layers, x 300.

8. A more developed pro-embryo. In its upper cells are found spherical

irregular masses, of a glassy substance. The wall of the corpusculum —
which is detached from the neighbouring cells, and is adherent to the
specimen — exhibits shallow pits, and flat ridges, seated on the outer
side, whose course corresponds with that of the edges of contact of the
neighbouring cells (end of July), x 300.

Figs. 9, 10. Pinus sylvestris.

9. 10. Young embryos in longitudinal section ; from the 28th June until 7th

July, x 250.

490 EXPLANATION OF THE FIGURES.

Fig. 11. Pinus balsamea.

FIG.

11. Longitudinal section of the embryo-sac of P. balsamea, filled by a few large
cells ; at the beginning of May of the first year.

PLATE LXI1I.
Tigs. 1 — 1-2. Taxus baccata.

1. Longitudinal section of an ovule at the end of March. The shaded part

shows the position of the cells destined to become embryo-sacs, x 30.

2. The cells of this part, x 300. The contents of the rudiments of the

embryo-sacs are contracted by tincture of iodine.

3. Apex of the ovule in the middle of April, in longitudinal section. The

course of the pollen-tube, which at this time is very delicate, is exposed,
x 150.

4. The embryo-sac and neighbouring cells from an ovule cut longitudinally ;

end of April, x 300.

5 — 7. Further developed embryo-sacs ; detached (6th May), x 300.

8. Embryo-sac and one of its neighbouring cells ; detached (17th May),

X 500.

9. Embryo-sac ; detached, x 300.

10. Longitudinal section of the nucleus of an ovule, through which two pollen-

tubes have penetrated to the embryo-sac (22nd May), x 200.

11. Lower end of a pollen-tube with a portion of the endosperm cut through

longitudinally ; both detached. Impregnation has not yet occurred ; the
rosette is still uninjured, x 350.

12. Young rudiment of a pro-embryo with a portion of the membrane of the

corpusculum detached, x 350.

Fig. 13. Taxus Canadensis.

13. Apex of the endosperm with the end of the pollen-tube and an impregnated

corpusculum with the rudiment of a pro-embryo in longitudinal section ;
on the 10th June, x 300.

PLATE LXIV.

Fig. 1. Taxus Canadensis.

1. Longitudinal section of the upper end of an endosperm witli the pollen-
tube; on June 5th. Two corpuscula are laid open by the section;
the right hand one is impregnated ; the impregnated germinal vesicle
occupies the lower third part of it, x 300.

Fig. 2. Taxus baccata.

2 Lower ends of two pollen-tubes with portions of the endosperm, which has
been cut through longitudinally, soon after impregnation. The pollen-
tubes are drawn away for a short distance from the endosperm ; the left
hand one has in consequence been torn at the outermost apex, x 300.

EXPLANATION OF THE FIGURES. 491

Figs. 3, 3*, 4. Thuja orientalis.

FIG.

3. End of a pollen-tube, detached, x 250.

3*. Some of the contents of the pollen-tube shown in fig. 3, X 500.

4. End of a pollen-tube detached, x 250.

Figs. 5, 6. Juniperus Siberica.

5. Nucleus of the ovule with the lower portion of the integument of the

ovule, in longitudinal section ; on June 5th of the first year, x 300.

6. Detached embryo-sac at the end of May of the second year, which has be-

come filled with cellular tissue for the second time. The membrane of
the embryo-sac is swollen with water, x 60.

PLATE LXV.

Fig. 1. Juniperus Sibirica.

1. Apex of the embryo-sac filled with .endosperm, in longitudinal section ;

three corpuscula are exposed ; on June 9th of the second year, X 300.

Figs. 2 — 7. Juniperus communis.

2. Corpuscula cut longitudinally, with a small portion of the endosperm and

the pollen-tube ; on the 20th July, X 300.

3. Three impregnated corpuscula, with the lower portion of the pollen-tube

(longitudinal section of an endosperm on July 28th), x 300.

4. Pro-embiyo consisting of three longitudinal rows of cells.

5. Longitudinal section of an impregnated ovule (the integument is omitted

in the drawing). The pointed line in the endosperm shows the
boundaries of the region in which the cells are loosened and partly dis-
solved. The development of the embryos of this specimen corresponds
almost with that of the one shown in fig. 7. (Beginning of August.)
X 30.

6. Lower end of one of the isolated longitudinal rows of cells of a pro-embryo,

with the mother-cell of the embryo still undivided, x 150.

7. A similar specimen, with a more developed rudiment of the embryo.

8. A similar specimen.

Figs. 9 — 10*. Thuja orientalis.

9. Upper end of the endosperm with the group of corpuscula and two pollen-

tubes which have penetrated into the depression above it, in longitu-
dinal section ; on June 18th, x 250.

10. A similar specimen with a single pollen-tube, which has sent prolongations
into the corpuscula; on June 28th, x 250.

10*. The pollen-tube of the latter preparation detached.

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INDEX.

in

of

of

Abies excelsa, fecundation of, 418.

Abietinese, anatropal ovules of, 400 ;
nucleus in, 400 ; corpuscula of,
410.

Abnormal fruit in mosses, Gumbel's
observations on, 180.

Adiantum, antheridia of, 187 ; germi-
nation of, 183.

Adventitious roots, 203 ; of Isoetes,
336.

Adventitious shoots of abortive pro-
thallia of ferns, 197.

Agardb, observations on the germina-
tion of Equisetacese, 304.

Air-cavities of Marchautiese, 111.

Air-cavities of antheridial discs
Marchantia polymorpha, 121 ;
receptacle of do., 117.

Alicularia, antheridia of, 65.

Alicularia scalaris, arrangement
cells in leaves of, 63 ; cell-multipli
cation in apex of stem of, 442
development of fruit of, 74, 77, 78
development of perianth in, 69
germination of, 54 ; ramification of
prothallium of, 84.

Allosurus, abortive prothallia of, 197.

Alternation of generations in mosses
and ferns, 434.

Amoeboid movements of primordial
utricle of spore-mother-cells in
Phascitm cuspidatum, 163.

Analogy of the prothallium and frond
of ferns, to the leafy plant and fruit
of mosses, 435.

Aneura, archegonia of, 44 ; cell-
development in stem of, 43 ; growth
of stem in, 43 ; ramification of,
44.

Aneura multifield, 21; elaters of, 86;
spermatozoids of, 87.

Aneura pinguis, 21 ; development of
antheridia of, 45.

Anther of Pinus, 401.

Antheridia of Aneura pinguis, 45 ; of
Anthoceros, 7 ; of Botrychium Lu-
naria, 308 ; of Equisetacese, 293 ;
observed by Thuret and Milde, 306;
of ferns, 185 ; discovered by Nageli,
258 ; of Fossombronia pusilla, 65 ;
of Jungermanniae, 87 ; of Junger-
mannia, Lophocolea, Radula, Mado-
theca, Alicularia, Erullania, Fossom-
bronia, Haplomitrium, 65 ; of
Liverworts, »Gott.sche's views on,
erroneous, 88 ; of Lophocolea biden-
tata, rarity of, 72 ; of Lophocolea hete-
rophylla, Radula complanata,Junger-
mannia divaricata, and Frullania
dilatata, 73 ; of Madotheca platy-
phylla, 65, 67 ; of Marchantia poly -
tnorpha, 120 ; of Metzgeria furcata,
43 ; of mosses, 152 ; Hedwig on,
175; of Ophioglossum,Metteniuson,
316 ; of PelHa epiphylla, 29 ; great
number of in Pellia epiphylla, 31 ;
of Rebouillia hemispherica, 122 ; of
Riccia glauca, 93, 94; of Riella,
99; of Sphagnum, 154; observa-
tions on, in Sphagnum, by Schleiden,
155, 177; and by Schimper and
Unger, 1?7.

Antheridia, production of, on adven-
titious shoots of the prothallium of
ferns, 197.

Anthoceros, early growth of, 1, 3 ;
reference to figures of, and observa-
tions on, by Bischoff, Nees von
Esenbeck, and Schacht, 19.

Archegonia of Aneura, 44 ; of Antho-
ceros, 9 ; of Archidium, 149 ; of
Archidium phascoides, 152; oiBotry-

494

INDEX.

chium Lunaria, 308 ; of Calypogeia
Trichomanes, 70 ; of Dicranum, 149 ;
of Equisetaceee, 298 ; Bischoff and
Milde on, 306 ; of Fegatella conica,
114 ; of ferns, 189 ; their nature
detected by Lesczyc-Suminski, 258 ;
observations on by Nageli, 258 ;
Schaclit, 260 ; and Von Mercklin,
261 ; of Fissidens, 149 ; of Fossom-
bronia pusilla, 67, 71 ; of Frullania,
68 ; of Funaria, 149 ; of Isoetes
lacustris, 340 ; structure of in
Jungermanniae, described by Hed-
wig, 85 ; of leafy Liverworts, 67 ;
of Marchantia polymorpha, 115 ; of
Marsilea pubescens, 327; of Metzgeria
furcata, 43 ; of mosses, 148 ; obser-
vations on, by Hedwig, 175 ;
Schimper and Valentine, 177 ; of
Ophioglossum, Mettenius on, 316;
of Pellia epiphylla, 32 ; of Phascum,
149 ; of Filularia globulifera, 322 ;
Nageli on, 335 ; of Polytrichum,
149 ; of Radula complanata, 67 ; of
Rebouillia hemispherica, 113; of
Riccia glauca, 93, 95 ; of Riella,
99 ; of Salvinia nutans, 329 ; of
Selaginella, 393 ; of Sphagnum,
142, 150 ; Targionja hypophylla
118.

Archegonia of Mosses, Liverworts,
Ferns, Equisetacese, Rhizocarpeae,
and Lycopodiacese compared, 434.

Archidium, Schimper on the fructifica-
tion of, 169.

Archidium phascoides, archegonia of,
149, 152 ; fruit of, 160, 168, 169.

Arrangement of fronds in Isoeteaj,
Alexander Braun on, 335.

Aspidium filix-mas, antheridia of, 187;
archegonia of, 191; development of
embryo in, 200 ; development of
vegetative organs of, 208, 226 ;
germination of, 183 ; production of
fronds in, 226 ; production of roots
in, 243.

Aspidium spinulosum, development of
fronds in, 230.

Asplenium Bellangeri, adventitious
buds of, 247 ; vegetation of, 245.

Asplenium filix-femina, adventitious
buds of, 247 ; development of
fronds in, 230 ; division of stem of,
247 ; structure of terminal bud,
stipes and roots of, 246; vegetation
of, 245.

Asplenium septentrionale, germination

of, 183.
Asplenium Trichomanes, development

of fronds in, 230.

Balantium Karstenianum, cellular
hairs of stem-bud of, 212.

Bark of stem of Fteris aquilina, 215.

Bast-cells of stem of Fteris aquilina,
215 ; formation of in stem-bud,
217.

Bischoff on Anthoceros, 19 ; his dis-
covery of the archegonia of Equise-
tacese, 306 ; on the production of
antheridia and archegonia on the
prothallium of Equisetum sylvaticum,
297 ; on the germination of Equi-
setacese, 305 ; on the sexual organs
of the prothallium of ferns, 257 ;
on the development of the fruit-
stem in Fegatella, 115 ; on the
germination of the spores of the
Jungermannise, 83 ; on Lttnularia
vulgaris, 126; on Marchantiese, 122;
on Pellia, 26 ; on Rebouillia hemis-
pherica, 114, and its antheridia, 122;
on the fructification of Riccia, 97;
on the sporangia of Selaginella, 3S7.

Blasia, 47.

Stasia pusilla, germination of, 83 ;
spore-mother-cells of, 82.

Botrychium Lunaria, germination and
development of, 307 ; succession
of fronds in, 311.

Branches, fertile, of Selaginella,
384.

Braun, Alexander, on the fronds and
roots of Isoetese, 337 ; on the stem
of Isoetes, 354 ; on the interchange
of fertile and sterile leaves in
Isoetes lacustris, 362 ; on the growth
of Ophioglossum and Botrychium,
310 ; on phyllotaxis in Sphagnum,
136.

Brogniart on the stems of ferns,
262.

Brown, Robert, his discovery of the
poly-embryony of Coniferse, 432.

Bruchs on the fruit of mosses, 180.

Bryum, antheridia of, 152; develop-
ment of leaves of, 142.

Bryum argenteum, development of
fruit of, 156.

Bryum caspitosum, antheridia of, 153.

Bud-receptacle in Blasia, 50.

Bud, terminal, of Aspidium filix-mas,

INDEX.

495

227 ; division of, in Asplenium filix-
femina, 247 ; of Pilularia, 325.

Buds, production of, in Aneura mulli-
jida, 46 ; in Anthoceros, 18, 48 ;
development of, in Pteris aquilina,
225 ; of Lunularia, 104, 107 ; of
Marchantia, 104, 107 ; of Kiccia,
48.

Buds, adventitious, of Aspidium filix-
rtias, A. spinulosum, and A. oreopteris,
245 ; Asplenium Bellangeri, 247 ; of
Asplenium filix-femina, 245, 247 ;
of Equisetaceae, 275, 303 ; of Ma-
rattia Cicutcefolia, 255 ; of Nephro-
lepis, 247 ; of Opliioglossum, 315 ;
of Strulhiopteris Germanica, 245,

247.

Buds, reproductive of Blasia, 48 — 50 ;
Corda's description of their germi-
nation, 48.

Bulbils of Lunularia, 104, 107; of
Marchantia, 104, 107.

Calypogeia Trichomanes, archegonia of
7U ; calyptra of, 80 ; cell-multiplica-
tion in apex of cell of, 442 ; deve-
lopment of fruit of, 74, 77, 80;
observed by Gottsche, 86; develop-
ment of perianth in, 70.

Calyptra of Aneura multifida, 45 ; of
Anthoceros, 13 ; of Calypogeia
Trichomanes, 80; of Liverworts,
development of, 79 ; of Junger-
mannia bicuspidata, 79 ; of Frul-
lania dilatata, 80 ; of Marchantia
polymorph^ 116 ; of mosses, 159;
of Radula complanata, 79 ; of Rebou-
illia hemispherica, 113; of Riccia
glauca, 96 ; Targionia hypophylla,
119.

Calyx of leafy Liverworts, 68.

Cambium layer peculiar to Isoetes
among vascular Cryptogams, 372.

Capsule of Fegatella conica, 115; of
Pellia epiphylla, 37 ; of Kiella, 100.

Cell, apical, of terminal bud of stem
in Aspidium filix-mas, 231 ; in
Equisetaceae, 267 ; in Ferns, 231 —
239 ; in Marattia cicutafiolia, 254 ;
in Nephrolepis undulata, and N.
splendens, 248 ; in Niphobolus ru-
pestris, and N. chinensis, 218 ; in
Opliioglossum vulgatum, 314 ; in
Platycerium alcicome. 253 ; in Poly-
podium aureum, P. punctalum, P.
cymatodes, and P. vulgare, 248 ;

division of, in Selaginella, 273 ; of
Sphagnum, 129.

Cell-development in the stem of
Aneura, 43 ; in stem and shoots of
Anthoceros, 4 ; in the germ-plant
of Frullania dilatata, 52 ; in the
germ-plant of Jungermannia bicus-
pidata, 53 ; in the stem of Metz-
geria ' fur cat a, 42; in the shoots of
Pellia epiphylla, 27.

Cell-division in leaves of Fegatella
conica, 109.

Cell-formation in spores of Isoetes
lacustris, 339 ; importance of the
study of the spores of Pellia epi-
phylla in regard to, 39.

Cell-multiplication in autheridia of
Equisetacese, 294 ; in archegonia of
Equisetaceae, 298 ; of ferns, 190 ;
in the developing fruit of Equise-
taceae, 301 ; in the embryos of
Pteris aquilina and Aspidium filix-
mas, 201; in the embryo of Sal-
vinia nutans, 333 ; in germ-plant
of Radula complanata, 55 ; in the
stem of Equisetum, 272 ; in the
stem of Frullania dilatata, 56, 57;
in the stem of the leafy Junger-
mannise, 56, 442; Kageli on, 84 ;
in the stems of Jungermannia bicus-
pidata, 56, 57, J. connivens, 57,
/. exsecla and /. trichophylla, 84 ;
in stem of Lophocolea bidentata, 56 ;
in stem of Metzgeria furcata, 84 ;
in stem of Selaginella, 374; in
stem of Sphagnum, 130 ; in stem
of Trichocolea tomenfella, 56 ; in
terminal bud of Blasia, 49, of
Equisetaceae, 267, of Pteris aquilina,
217; in first frond of Pteris aqui-
lina, 208 ; in young fronds of
Niphobolus rupestris and N. splen-
dens, 249, and of Polypodium
aureum, 250 ; in leaves of Bryum,
Hypnum, Phascum, and Poly-
trichum, 142 ; in leaves of Ortho-
trichum affine, 139 ; in leaves of
Sphagnum, 136 ; Nageli on, 140 ;
in leaves of Sphagnum squarrosum,
1 42 ; in roots of Aspidium filix-
mas, 244, of Equisetum, 279, and
of Isoetes lacustris, 348 — 356.
Cell-succession in apex of Aspidium
filix-mas and A. spitmlosum, 241 ;
in apex of leaf-buds of phaenoga-
mous plants, 239.

496

INDEX.

Cells, arrangement of in stems of
Equiseta, 272 ; pitted in Sphag-
num, 134 ; scalariform of Pteris
aquilina, 219.

Ceratopteris, germination of, 183.

Ceratopteris thalictroides, antheridia
of, 187 ; archegonia of, 191, 193.

Chlorophyll-bodies in cells of Antho-
ceros, 6 ; of Phascum, 146.

Chlorophyll-granules of Metzgeria
furcata, small size of, 42.

Chlorophyll-vesicle, 6.

Cilia of spermatozoids of ferns, 189.

Classification of mosses and liver-
worts, 407.

Columella of Anthoceros, 13.

Coniferae, development of pollen in,
401 ; differences of, from phceno-
gams, 441 ; ovules of, 400 ; poly-
embryony of, discovered by "Robert
Erown, 432.

Corda on the reproductive buds of
Blasia, 48 ; on the pollen-tube of
Conifers, 432.

Corpuscula of Coniferae, 410 ; num-
ber of, in different species, 411,
412 ; free cells in, 412 ; of Pinus
canadensis and P. picea, 411.

Cramer on cell-succession in the end
of the stem of Equisetum, 207.

Creeping-stem of Pteris aquilina, 212.

Cupressus, corpuscula of, 410; de-
velopment of endosperm in, 410.

De Bary, observations on the spores
of Lycopodium inundalum, 399.

De Vnese and Harting on the Marat-
tiaceae, 254.

Dicksonia rubiginosa, cellular hairs of
stem-bud of, 212.

Dicksoniae, stems of, 213.

Dicranum, archegonium of, 149.

Dicranum scoparium, terminal bud of,
129.

Dillenius on Marchantia polymorpha,
123.

Dipiolaena, 47.

Disc, antheridial, of Marchantia poly-
morpha, 120.

Duriena, leaf of, 98.

Ehrhart on the prothallium of ferns,
257.

Elateis of Aneura multifida, develop-
ment of, 45 ; Schmidel on, 86 ; of
Anthoceros, 13; of Equisetaceae,

287, Sanio's observations on ab-
normal formation of, 291 ; of Fos-
sombronia pusilla, 82 ; of Junger-
mannia bicuspidata, 78, 79, 81 ; of
Jungermannia divaricata, 75 ; of
Jungermanuise, Gottsche on, 87 ;
of Pellia epiphylla, 38 ; of Tar-
gionia hypophylla, 120.

Embryo, development of, in Abietineae,
421 ; position of, on the prothal-
lium, in Botrychium Lunaria, 308 ;
development of, in Coniferae, 406,
observations of Hartig, Gottsche
and Pineau on, 407 ; formation of,
in Coniferae, intermediate between
that of cryptogams and phceno-
gams, 408, opinions of Schleiden,
Schacht and Geleznow on, 428 ;
development of in Equisetaceae, 301 ;
of Ferns, 200 ; development of in
Isoetes lacuslris, 343 ; formation of,
in Larix, Geleznoff's statements
on, 422, of Ophioglossum, Mette-
nius on, 316 ; formation of iu
Pilularia, 323 ; production of iu
Salvinia natans, 332 ; development
of in Selaginella, 395.

Encalypta, antheridia of, 152 ; ca-
lyptra of, 159 ; spore-mother-cells
of, 160.

Endosperm, development of, in Coni-
ferae, 408.

Epidermis, formation of, in Equise-
taceae, 273.

Equisetaceae, production of antheridia
in, 293 ; development of archego-
nia in, 298 ; fecundation and de-
velopment of embryo in, 300, 301 ;
obstacles to germination of, 296 ;
prothallium of, 292; spermatozoids
of, 294; terminal bud of, 267;
vegetation of, 303.

Equisetum arvense, adventitious buds
of, 276, 304 ; antheridia of, 296 ;
apical cells of antheridia of, 294 ;
fructifying shoots of, 2S0 ; germi-
nation of, 292, 297 ; development
of germ-plant of, 304 ; prothallium
of, dioecious, 294 ; production of
male prothallia in, 297 ; spermato-
zoids of, 296.

Equisetum hyemale, stem of, 271.

Equisetum limosum, adventitious buds
and shoots of, 2/6, 277 ; antheridia
of, 294, 296 ; cell-multiplication in
terminal bud of, 268 ; germination

INDEX.

497

of, 292 ; growth of leaves of, 271 ;
pith of, 275 ; rhizome of, 278 ;
stem of, 271.

Equisetum palustre, adventitious buds
of, 276 ; germination of, 292 ; pith
of, 275 ; prothallium of, dioecious,
293 ; spore-mother-cells and spores
of, 283 ; stem of, 271.

Equisetum pratense, formation of ad-
ventitious buds in, 275 ; pith of,
275 ; prothallium of, dioecious, 293 ;
stem of, 271. '

Equisetum variegatum, pith of, 275 ;
stem of, 271.

Exosporium of Anthoceros, Kiitzing
on, 17; of Isoetes lacustris, Roper
and Scnleiden on, 338.

Eegatella conica, Hedwig on, 123 ;
Schmidel on, 123 ; archegonia of,
114; capsule of, 115; rudimen-
tary fruit of, 115 ; cell-division in
leaves of, 109 ; shoots of, 102 ;
vegetative organs of, 102.

Ferns, 182 ; alternation of genera-
tions in, 434, 435 ; antheridia of,
] 85 ; antheridia and spermatozoids
of, discovered by Nageli, 258 ;
archegonia of, 189, observed by
Nageli, 258; embryo of, 200;
growth of first fronds of, 207 ;
germinal vesicle of, 193 ; germina-
tion of, 182 ; impregnation of, 198,
described by Lesczyc-Suminski,
258 ; prothallium of, observed by
Ehrhart, 257 ; development of
roots of, 203, 205 ; spermatozoids
of, 187, 188, 189; development of
vegetative organs of, 208.

Fissideus, archegouium of, 149 ; de-
velopment of fruit of, 156 ; leaf of,
143, 144,

Fossombronia pusilla, antheridia of,
65; archegonia of, 67, 71 ; develop-
ment of leaf of, 58, 63 ; spermato-
zoidsof, 67; discovered by Schmidel,
87; spore-mother-cells and elaters
of, 82.

Fritzsche, observations on the pollen
of the Abietinese, 405.

Fronds, of Aspidium filix-mas, ar-
rangement of, 228, tirst formation
of, 243, production of, 226; of
Aspidium spinulosum, Asplenium
filix-femina and A. Trichomanes,
development and arrangement of,

230 ; of Botrychium, succession of,
311 ; of Ferns, growth of, 207 ; of
Isoeteee, A. Braun on the arrange-
ment of, 337 ; adventitious, of Ma-
rat tia cicutafolia, 255 ; of Ophio-
glossum vulgatum, arrangement and
succession of, 313 ; of Pilularia,
production of, 324 ; of Platycerium
alcicome, 251 ; of Platycerium
grande, 253 ; of Polypodium vul-
gare and P. Bryopteris, 249 ; of
Pteris aquilina, arrangement of,
212 ; duration of development of, in
young and old plants, 222 ; produc-
tion of new, 221 ; and production
of in old plants, 224.

Fronds and sporangia of ferns, analo-
gous to fruit of mosses, 435.

Fructification of Anthoceros, 7 ; of
Archidium, Schimper on, 169 ; of
Riccia glauca, 92, 93.

Fruit, development of, in Alicularia
. scalaris, 74, 77, 78 ; in Aneura
multifida, 44, 45 ; in Anthoceros,
11, 12; in Calypogeia Trichomanes,
74, 77, 80; in Equisetum, 280 ; in
ferns, 256; in Frullania dilatata,
74, 78, 80, 82 ; in Jungermannia
divaricata, 74, 75, 76 ; in /. bicus-
pidata, 74, 77, 78, 82; in J".
trichophylla, 77, 82 ; in Lophocolea
heterophylla, 77, 78 ; in mosses,
156; in Fellia epiphylla, 34; in
Radula complanata, 74, 77, 78, 82 ;
in Rebonillia hemispherical 114 ; in
Riccia glauca, 97.

Fruit, abnormal, in mosses, 180; of
Anthoceros, 18; of Fegatella conica,
115; of Jungermannise, observed
by Gottsche, 86 ; of Lophocolea
bidentata, its rarity, 72; of Mar-
chantia polymorpha, 116; of mosses,
H. von Mold and Lantzius-Beninga
on, 179, Bruchs on, 180; sheath
of, in Fellia epiphylla, 36 ; of Pilu-
laria globulifera, 320; of lliclla,
100 ; of Targionia hypophylla, 119.

Fruit-stem of Fegatella conica, Schmi-
del and Bischoff on the detachment
of, 115.

Frullania, 441 ; antheridia of, 65 ;
archegonia of, 68.

Frullania dilatata, relations of anthe-
ridia and archegonia in, 73 ; calyp-
tra of, 80; cell-multiplication in
stem of, 56, 57, 442 ; fruit of, 74,
32

498

INDEX.

78, 80, 82 ; germination of, 51 ;
development of leaves in, 61 ; de-
velopment of perianth in, 69 ;
spermatozoids of, 67 ; spore-mother-
cells of, 81.

Funaria hygrometrica, antheridia of,
152, 153 ; arcbegonia of, 149 ;
fruit of, 156,157; germinal vesi-
cle of, 151; Hedwig on the ger-
mination of, 176 ; paraphyses of,
153 ; spermatozoids of, 1 54 ; spores
and spore-mother-cells of, 160, 167.

Furrows of stem in Isoetes, 367.

Geleznow on the formation of the

embryo in Conifers?, 428.
Gemma?, formation of, mEiecm glauca,

97.

Generations, alternation of, in mosses
and ferns, 434.

Geocalycea?, development of fruit of,
78.

Germinal vesicle, of Conifera?, evolu-
tion of, 426; of Equisetacea?, 299 ;
of ferns, 103 ; of Funaria hygro-
metrica, 151 ; of Juniperus commu-
nis and /. sabina, 431 ; of mosses,
150 ; of Riella, 100 ; of Taxus
baecata and T. canadensis, 430 ; of
Thuja orient 'a lis, 431.

Germination of Alicularia scalaris,
54 ; of Blasia pusilla, 83 ; of Bo-
try chium lunaria, 307 ; of Equise-
taceae, observations on by Vaucher
and Agardh, 304, byBischoff, 305 ;
of fern-spores, described by Kaul-
fuss, 257; of Isoetes, 371, Mette-
nius 6*it337; of Isoetes lacustris,
Karl Mjf&er's observations on, 337 ;
of Jungerrnannia?, 83 ; of Junger-
mannia bicuspidata, 52 ; of /.
crenulata, 5 4, '84 ; of J. divaricata,
54 ; of Lophocolea heterophylla, 54 ;
of mosses, 160, Hedwig on, 175,
Nageli and Schimper on, 176; of
mosses and ferns, 435 ; of Ophio-
glossum, Mettenius on, 315 ; of
Pellia epiphylla, 21 ; of Filularia
globulifera, 321; of Radula com-
planata, 55 ; of Salvinia natans,
329 ; of Sarcoscyphus Funkii, 54 ;
of Selaginella, Mettenius on, 337-
Germ -plant, of Botry chium Lunaria,
307 ; of Equisetacea?, development
of, 302, 304 ; of Riccia glauca, 89 ;
of Selaginella, 396.

Gottsche, on the fructification of
Calypogeia Trichomanes, 70, 80;
on the development of the embryo
in Coniferse, 407 ; on the shoots of
Haplomitrium Hookeri, 64 ; on the
antheridia of Haplomitrium, 88 ;
on the elaters and perianth of
Jungerrnannia?, 87; on the young
fruit of Jungerrnannia?, 86 ; on the
germination of the spores of Jun-
germanniaj, 83; on the develop-
ment of the leaves of Jungerrnannia?,
■85 ; on the spermatozoids of Jun-
gerrnannia?, 87 ; his erroneous
views of antheridia of Liverworts,
88 ; on Marchantiea?, 122 ; on the
seed and embryo of Pinus, 433 ;
on Preissia cornmutata, 127.
Gris, Arthur, on chlorophyll-bodies,

147.
Grbnland on the germination of the
spores and the ramification of the
prothallium in Jungerrnannia?, 84 ;
on Lunularia vulgaris, 127 ; on
Marchanliu polymorpha, 127.
Gumbel, observations on abnormal

fruit in mosses, ISO.
Gymnogramma calomelanos, archegonia
of, 192, 194 ; abortive prothallia
of, 197.
Gymnogramma ehrysophylla, abortive

prothallia of, 196, 197.
Gymnostomum, antheridia of, 152 ;
calyptra of, 159 ; spore-mother-
cells of, 160.
Gymnostomum ovatum, spore-mother-
cells of, 164.
Gymnostomum pyriforme, antheridia
of, 153 ; fruit of, 157, 160 ; Hed-
wig's observations on the germina-
tion of, 175 ; spore-mother-cells of,
166 ; spores of, 167.

Hairs, cellular, of the stem-bud in
Pleris aquilina, 212.

Hanstein on the stems of ferns, 202.

Haplomitrium Hookeri, antheridia of,
65 ; Gottsche on, 88 ; development
of leaves of, 63, 85 ; half-subterra-
nean shoots of, 64.

Hartig, on the suspensor in the Coni-
fera?, 433 ; on the development of
the embryo in the Couifera?, 407.

Hedwig, on Fegatella conica, 123 ;
on the antheridia of Jungerrnannia?,
87; observations on the archegonia

INDEX.

499

of Jungermannise, 85 ; on the ger-
mination of the spores of Junger-
mannise, 83 ; on the reproduction
of mosses, 175 ; on the germina-
tion of mosses, 175 ; experiments
on the germination of Gymnostomum
pyriforme, 175, and of F anuria
hygromeirica, 176 ; on the fructifi-
cation of Riccia, 97.

Uemitelia Gupensis, frond-like bodies
at base of stipes of, 213.

Henfrey on the impregnation of ferns,
261 ; on Marchantia polymorpha,
127.

Hiibener on the pro-embryo of Schis-
tostega, 173.

Hybridity in mosses, 181.

Hypnum, development of leaves of,
112; terminal 'bud of, 129.

Impregnation in Conifera?, 406 ;
Schacht's observations on, 422 ; in
Equisetaceas, 300; in ferns, 198, de-
scribed by Lesczyc-Summski, 258,
observations on by Wigand, 259,
Hofmeister, 260, Von Mercklin,
Metteuius and Henfrey, 261 ; in
Isoetes, 370 ; in Isoetes lucustris,
370; in mosses, 156; in Pellia
epiphylla, 34 ; in Pilularia, 323.

Indusium of ferns, 256.

Inflorescence of Marchantia, 111.

Isoetese, peculiarities in the growth
of, indicated by H. von Mold, 336.

Isoetes, germination of, Mettenius on,
337 ; different numbers of furrows
in the stem of, 367, and differences
of growth in accordance with them,
368 ; resemblance of, to Coniferse,
in mode of reproduction, 370.

Isoetes adspersa, leaves of, 363.

Isoetes Durieui, leaves of, 363.

Isoetes Hystrix, leaves of, 363.

Isoetes lacustris, 335 ; Karl Midler's
observations on the germination of,
337.

Isoetes velata, leaves of, 363.

Jungermannia, antheridia of, 65 ;
archegonia of, 67.

Jungermannia bicuspidata, calyptra of,
79 ; cell-multiplication in stem of,
56, 57, 442; elaters of, 78, 79;
development of fruit of, 73, 74, 77,
78, 82 ; germination of, 52 ; Gron-

land on the ramification of the germ-
plant in, 54 ; development of leaves
in, 59 ; development of perianth in,
69 ; shoots of, 64 ; production of
spore-mother-cells in, 78, 79.

Jungermunnia connivens, development
of leaves of, 59 ; cell-multiplication
iu stem of, 57.

Jungermunnia crenulata, germination
of, 54, 84 ; arrangements of cells
in leaves of, 63 ; ramification of
prothallium of, 84.

Jungermunniu curtu, arrangement of
cells in leaves of, 63.

Jungermannia divaricata, antheridia
of, axillary, 73; cell-multiplication
in stem of, 56 ; elaters of, 75 ; de-
velopment of fruit in, 73, 74, 75,
76 ; germination of, 54 ; develop-
ment of leaves of, 59 ; development
of perianth in, 69 ; spermatozoids
of, 67.

Jungermannia exsecta, cell-multiplica-
tion in stem of, 84.

Jungermamda trichophylla, develop-
ment of fruit of, 77, 82 ; cell-mul-
tiplication in stem of, 84.

Jungermauuise, antheridia of, 87;
germination of, 83 ; impregnation
of, 73 ; development of leaves in,
85 ; variety of forms of leaves in,
57; perianth of, 87; ramification
of, 64, 85 ; development of spores
of, 86.

Jucgermanniae, leafy, development
of archegonium in, 67, 68 ; calyx
or perianth of, 68 ; spermatozoids
of, 67.

Juniperus, cell-division in anthers of,
404 ; corpuscula of, 410 ; develop-
ment of endosperm iu, 408 ; nu-
cleus of, 400.

Juniperus communis, fecundation of,
424.

Juniperus subina, fecundation of, 424.

Karsten on the stems of ferns, 263.

Kaulfuss on the germination of fern-
spores, 257.

Kunze on the scales of Uemitelia
Capensis, 243.

Kutzing on the exosporium of Autho-
ceros, 17.

Lantzius-Beninga on the fruit of
mosses, 179.

500

INDEX.

Leaves, of Alicularia scularis, arrange-
ment of cells in 63 ; of Blasia pusilla,
47 ; of Equisetacese, formation of,
269 ; of Fegatella conica, cell-divi-
sion in, 109 ; of Fossombronia pusilla,
development of, 58, 63 ; of Frul-
lania dilatata, development of, 61 ;
of Haplomitrium, development of
63 ; oilsoeles lacustris, arrangement
of, 354, 356 ; development of, 344;
fertile, of Iso'etes lacustris, 362 ;
sterile and fertile, interchange of
in Iso'etes lacustris, 362 ; of Jun-
germannise, 57, 63 ; Gottsche on
the development of, 85 ; of Jun-
germannia curia and crenulata,
arrangement of cells in, 63 ; of
Jungermannia bicuspidata, conni-
vens, and divaricata, development
of, 59 ; of Lophocolea, development
of, 58 ; of Lnnularia, development
of, 110 ; of Marchantia polymorpha,
110 ; of mosses, 142, 147 ; Niigeli,
Sehleiden, and Grisebach on the
growth of, 147 ; pocket at base of,
143 ; of Orlkoirychum affine, deve-
lopment of, 139 ; of Phascum cuspi-
datum, 146 ; of Ptilidium ciliare,
development of, 60 ; of Radula
complanata, 63; of Rebouillia, 110;
of Riccia glauca, 92 ; of Riella
Reuteri, and R. (Duriena) helico-
phylla, 98 ; of Selaginella, produc-
tion of, 376, 396 ; of Sphagnum,
arrangement of, 136 ; development
of, 135 ; of Targionia, development
of, 110.

Lepidozia reptans, cell-multiplication
in apex of stem of, 442.

Lesczyc-Suminski, on the archegonia
and fecundation of ferns, 258 ; on
the spermatozoids oiPterisaquilina,
189.

Lindenberg on the fructification of
Riccia, 97.

Linnaeus on Marchantia polymorpha,
133.

Liverworts and mosses not natural
equivalent groups, 436 ; classifica-
tion of, 437.

Liverworts, leafy antheridia of, 65 ;
development of archegonia in, 67 ;
calyx or perianth of, 68.

Lophocolea, antheridia of, 65 ; deve-
lopment of leaves of, 58.

Lophocolea bidentata, 441 ; cell-multi-

plication in stem of, 56 ; scarcity of

antheridia and fruit in, 72.
Lophocolea heterophylla, antheridia of,

axillary, 73 ; development of fruit

of, 74, 77; germination of, 54;

leaves of, 5S.
Lunularia, buds or bulbils of, 104 :

development of leaves of, 11 0.
Lunularia vulgaris, shoots of, 108 ;

vegetative organs of, 102 ; Bischoff

on, 126; Gionland on, 127.
Lycopodiaeeae, reproduction of, 398.
Lycopodiuni, mode of vegetation of,

resembling that of Polypodiaceae,

398.
Lycopodiuni clavatum, inundalum, and

Selago, experiments in sowing spores

of, 398.
Lycopodiuni inundalum, De Bary's

observations on the spores of,

399.

Maerosporangium of Selaginella hor-
tensis, 387.

Macrospores, structure of, in Iso'etes
lacustris, 338 ; development of, in
Selaginella hortensis, 387 ; in S.
Galeoitii, helvetica, Martensi, and
spinulosa, 398 ; in S. helvetica, and
hortensis, 393.

Madotheca platyphylla, development
of antheridia of, 65, 67 ; cell-multi-
plication in apex of stem of, 442 ;
spermatozoids of, 67-

Marattia cicutcefolia, vegetation of
254.

Marattiacese, De Vriese and Harting
on, 254.

Marchantia, buds or bulbils of, 104 ;
104 ; inflorescence of, 111 ; motile
spermatozoids first seen in by
Unger, 127.

Marchantia polymorpha, antheridia of
120 ; development of leaves of, 110 ;
shoots of, 108 ; spermatozoids of
121 ; vegetative organs of, 102 ;
Dillenius, Linnaeus, Micheli, Mirbel,
and Rupp on, 123 ; H. von Mohl
and Nageli on, 124 ; Gronland and
Henfrey on, 127.

Marchantieae, 102 ; air-cavities of, 111,
117 ; antheridia of, 120; leaves of,

109 ; stem of, 110 ; stomata of,

110 ; Bischoff, Gottsche, and Nees,
von Esenbeck on, 122 ; Schmidel,
123 ; Thuret on, 128.

INDEX.

501

Marsilea p?ibescens, 318 ; macrospore
of, 325 ; germination of, 326.

Mercklin on the archegonia of ferns,
261 ; on vessels in the protliallium
of ferus, 207.

Mettenius on the growth of Botry-
chium 310, 311 ; on the impregna-
tion of ferns, 261 ; on the stems of
ferns, 263 ; on the spermatozoids of
Isoeles lacustris, 342 ; on the spores
and germination of Isoeles and
Selaginella, 337 ; on the germina-
tion of 0| hioglossum, 315 ; on the
Rbizocarpese, 335 ; on the spores
of Salvinia natans, 330; on the pro-
thallium of Selaginella, 392 ; on
abortive archegonia in Selaginella,
395 ; on the spores of Selaginella,
390.

Metzgeria furcata, cell-multiplication
in stems of, 84 ; Nageli on the
growth of, 41.

Meyer on spermatozoids of Aneura,

87.

Micheli, on Marchantia polymorpha,
123.

Microsporangia of Selaginella, 391.

Microspores of Isoetes lacustris, struc-
ture of, 341, production of sperma-
tozoids by, 342 ; of Salvinia nutans,
331 ; of Selaginella, 391, 394.

Milde, description of the antheridia and
spermatozoids of Equisetacese, 306;
observations on the archegonium of
Equisetaceee, 306.

Mirbel, on the pro-embryo of the
Coniferse, 433 ; on Marchaniia
polymorpha, 123.

Mnium horn urn, paraphyses of, 153.

Mohl, H. von, on the formation of the
septa of the spore-mother-cells in
Anthoceros, 16 ; on chlorophyll
bodies, 146 ; on the bark of ferns,
215 ; on the structure of the stems
of ferns, 262 ; on the vascular
bundles of ferns, 225 ; on the
growth of Isoetese, 336 ; on the
development of the spores of Jun-
germannise, 86 ; ou Marchantia
polymorpha, 124 ; on the fruit of
mosses, 179 ; on the sporangia of
Selaginella, 387.

Moonwort, 307.

Morison on the growth of Scolopen-
driurn officinarum from spores, 257.

Mosses and liverworts, not natural

equivalent groups, 436 ; classfica-
tion of, 437.

Mosses, alternation of generations in,
434, 435 ; antheridia of 152 ; arche-
gonia of, 148 ; development of fruit
of, 156; abnormal fruit in, Gum-
bel's observations on, 180 ; ger-
minal vesicle of, 150 ; germination
of spores of, 170 ; impregnation of,
156 ; pocket at base of leaves of,
143 ; spore-mother-cells of, 160 ;
growth of stems of, 129 ; so-called
stigma of, 151.

Mother-cell, persistence of, in Equise-
tacese, 291.

Miillcr, Karl, on the germination of
Isoetes lacustris, 337.

Muller, II., on the stipules of Selagi-
nella, 378.

Nageli, on chlorophyll-bodies, 145 ;
on the archegonia, antheridia, and
spermatozoids of ferns, 258 ; on
the spermatozoids of ferns, 1S9;
on the stems of ferns, 202 ; on
cell-multiplication in the stems of
JungermanniaB, 84 ; on Marchantia
polymorpha, 124; on the growth of
Metzgeria furcata, 41 ; on the ger-
mination of mosses, 176; on the
leaves of mosses, 147 ; on the pro-
embryo of mosses, 172 ; on cell-
multiplication in the leaves of
Phascum, Bryum, Hypnum, and
Polytrichum, 1 42 ; on the produc-
tion of spermatozoids in Pilularia,
335 ; on cell-multiplication in leaves
of Sphagnum, 140 ; on cell-multi-
plication in apex of stem of Sphag-
num, 130.

Neckera complanata, antheridia of,
153.

Nees von Esenbeck, on Anthoceros,
19 ; on the germination of the
spores of the Jungermannise, 83 ;
on the ramification of Jungerman-
nise, 85 ; on Marchantiese, 122.

Nephrolepis, adventitious buds and
stolons of, 247.

Nephrolepis splendens, vegetation of,
245 ; apical cell of terminal bud of,
248.

Nephrolepis tuberosa, 247.

Nephrolepis undulata, apical cell of
terminal bud of, 248; vegetation
of, 245.

502

INDEX.

Niphobolus chinensis, apical cell of,

248.
Niphobolus lingua, apical cell of, 239.
Niphobolus rupestris, apical cell of,

239, 248.
Nothochlseua, abortive prothallia of,

197.
Nucleus in Abietinese, 400 ; in Juni-

perus, 400 ; in Pinus, 400 ; in

Taxus, 400 ; in Thuja, 400.

Ophioglosseae, 307.

Ophioglossum, prothallium of, obser-
vations of Mettenius upon, 315.

Ophioglossum pedunculosum, root-buds
of, 315.

Ophioglossum vulgutum, development
of vegetative organs of, 312.

Orthotrichum, calyptra of, 159.

Orthotrichum affine, development of
vegetative organs of, 139.

Ovules of Coniferse, 400.

Papillae, marginal, of leaves of Selagi-
nella, 380.

Paraphyses of mosses, 153.

Pellia epiphylla, 21.

Perianth, of Alicularia scalaris, 69 ;
of Calypogeia Trichomanes, 70 ; of
Frullania dilatata, 69 ; of Junger-
mannise, 87 ; of Jungermannia bicus-
pidata and /. dlvaricata, 69 ; of
leafy Jungermannia?, 68 ; repre-
sented in Pellia epiphylla by the
pouch-shaped covering of the arche-
gouium, 33 ; of Radula complanata,
68

Phascum, antheridia of, 152 ; arche-
gonia of, 149 ; calyptra of, 159 ;
development of fruit of, 156, 157,
158, 160 ; development of leaves of,
142 ; spore-mother-cells of, 160 ;
terminal bud of, 129.

Phascum bryoides, development of
fruit of, 160.

Phascum citspidatum,, spore-mother-
cells of, 160 ; spores of, 164, amoe-
boid movements of primordial utricle
in, 163.

Phascum serratum, pro-embryo of, 172.

Pliyllotaxis in Sphagnum, 136.

Pilularia, development of fruit of, 318.

Pineau, on the development of the
embryo in Conifer*, 407.

Pinnse, of frond, formation of, in Pteris
aquilina, 209.

Pinus, anther of, 401 ; Gottsche on
the seed and embryo of, 433.

Pinus Abies, fecundation of, 418.

Pinus balsamea, nucleus of, 400.

Pinus Canadensis, fecundation of, 418.

Pinus Larix, fecundation of, 419.

Pinus Strobus, nucleus of, 400.

Pinus syloestris, fecundation of, 417 ;
nucleus of, 400.

Pith of Equisetum, 274.

Plagiochila asplenioides, cell-multipli-
cation in apex of stem of, 442.

Platycerium alcicorne, germination of,
182 ; vegetation of, 251.

Pocket, of leaves of mosses, 143.

Pollen, of Abietinese, development of,
405 ; Fritzsche's observations on,
405 ; of Coniferse, development of,
401, resemblance of vital pheno-
mena of, to those of the microspores
of Pilularia, &c, 438 ; of Cycadeae,
406 ; of Ephedra, Schacht on, 406 ;
development of, in Pinus syloestris,
P. maritima, P. balsamea and P.
Larix, 402 ; in Juniperus, Thuja
occidenlalis, Abies pectinala, and
Picea vulgaris, 405.

Polleu-tubes of Couiferse, their entrance
into the endosperm, 415; develop-
ment of free spherical cells in the
ends of, 416 ; their penetration into
thecorpusculaprovedbyCorda, 432.

Pollen-tubes in Taxus, Juniperus,
Pinus syloestris, P. Mughus, P.
Austriacus, and P. Strobus, 406.

Poly-embryony of Coniferse, discovered
by Robert Brown, 432.

Polypodiacese, prothallia, and anthe-
ridia of, 186.

Polypodium aureum, apical-cell of,
239, 248.

Polypodium cymalodes, apical-cell of,
239, 248.

Polypodium Dryopleris, apical-cell of,
239 ; arrangement of fronds in, 249.

Polypodium punctatum, apical-cell of,
248.

Polypodium punctulatum, apical-cell of,
239.

Polypodium vulgare, apical-cell of,
239, 218; arrangement of fronds
in, 249.

Polytrichum, antheridia of, 152 ;
archegonia of, 149; development
of leaves of, 142 ; terminal bud of,
129.

INDEX.

503

Polytrkhum formosum, spermatozoids

of, 154.
Polytrichum juniperinum, antheridia

of, 153.
" Precursors" of the vascular bundles,

in Isoetes lacustris, 352.
Preissia commutata, Gottsche on,

127; Schmidel on, 123.
Presl, on the stems and fronds of Bo-

trychium, 310, 311.
Pringsheim, on the sterns of ferns, 264.
Pro-embryo, of Abietinese, 427 ; of Co-
niferse, described by Schleiden, 432 ;
Mirbel and Spach, 433; develop-
ment of Juniperus communis, J. Sa-
bina, and Thuja orientalis, 431 ; of
mosses, 171, 435 ; differences of,
from prothallium of ferns, 174; of
Liverworts, 435 ; of Pilularia glo-
bulifera, 322 ; of Sphagnum, Schim-
per on, 174 ; of Taxus, 430.
Prothallium, of Botrychium Lunaria,
307 ; of Equisetacese, develop-
ment of, 292 ; male, production of,
in Equisetum arvense, and E. pra-
tense, 297 ; female, production of,
in Equisetum palust re, 298 ; of ferns,
183 ; analogous to leafy plant of
mosses, 435 ; observed by Ehrhart,
257 ; sexual organs observed in, by
Bischoff, 257 ; adventitious shoots
of, 197 ; abortive, continued growth
of, 196 ; of Isoetes lacustris, 339 ;
of leafy Jungermannise, 84 ; of Mar-
silea puhescens, formation and struc-
ture of, 326 ; of Ophioglossum,
Mettenius on, 315 ; of Pilularia
globulifera, and P. minuta, forma-
tion of, 322 ; of Salvinia nutans,
production of, 329 ; of Selaginella,
production of, 392.
Prothallus, universality of, in plants,

126.
Psilotum triquetrum, growth of stem

in, 398.
Pteris aquilina, antheridia of, 187;
archegonia of, 191 ; development
of buds in, 225 ; development
of embryo of, 200 ; first frond of,
208 ; arrangement of fronds in,
212 ; production of new fronds in,
221 ; production of fronds in old
plants of, 224; germination of, 183;
growth of stem- bud in, 211 ; creep-
ing stem of, 212 ; structure of stem
of, 213.

Pteris serrulala, antheridia of, 187.
Ptilidium ciliare, development of
leaves in, 60 ; ramification of, 64.

Racomilrium ericoides, pro-embryo of,

171 ; terminal bud of, 129.
Radula complanata, antheridia of, 65,
73; archegonium of, 67; calyptra
of, 79 ; development of fruit of, 74,
77, 78, 82 ; germination of, 55 ;
cell-multiplication in germ-plant of,
56 ; development of leaves in, 63 ;
development of perianth in, 68 ;
spores of, 55.

Ramification in Aneura, 44 ; in Antho-
ceros, 2 ; in Equisetacese, 275 ; iu
Jungermanniae, 64 ; Nees von Esen-
beck on, 85 ; in Metzgeria furcata,
42 ; in Ortlwtrichum affine, 132 ; in
Sphagnum, 137 ; Schimperon, 138.

Rebouillia hemispherica, antheridia of,
122; archegonia, 113; calyptra,
113 ; fruit of, 114 ; development of
leaves of, 110; vegetative organs
of, 102.

Receptacles of Marchanlia polymor-
phs, air- cavities and stomata of,
117.

Rhizocarpeae, Mettenius and Schlei-
den on, 335.

Rhizome, development of, in Equise-
taceae, 304 ; of Equisetum limosum,
278.

Riccia glauca, buds of, 48 ; Schmidel,
Hedwig, Bischoff, Lindenberg, and
Unger, on the fructification of, 97.

Riella, antheridia of, 99 ; archegonia
of, 99 ; fruit of, 1O0 ; germinal
vesicle of, 100 ; spores of, 100.

Riella (Duriena) helicophylla, leaf of,
98.

Riella Reuleri, mode of growth of,
98 ; leaves of, 98 ; shoots of, 99.

Roper on the stem and fronds of Bo-
trychium, 309, 310, 311, 312; on
the exosporium of Isoetes lacustris,
338.

Root-buds in Ophioglossum, 315.

Rootlets of Metzgeria fureata, 42 ;
development of, in Pellia epiphylla,
23.

Roots, adventitious, 203 ; occurrence
of in Equisetum, 278 ; production
of in Selaginella, 397.

Roots, of Aspidium Jilix-mas, 229,
243 ; of germ-plants of Botrychium

504

INDEX.

Lunaria, 308 ; of ferns, development
of, 203, 205 ; Isoetese, A. Braun's
observations ou, 337 ; of Isoetes la-
custris, development of, 348, 356,
358, 307 ; of Marattia ciculafolia,
development of, 255 ; of Pilularia,
production of, 324 ; of Platycenum
alcicorne, 253 ; of Pteris aqtdlina,
development of, 210, 223; of Sela-
ginella, 3 S3.
B-upp, on Marckanliapolymorp/ia, 123.

Sachs, on chlorophyll-bodies, 147.

Salvinia nutans, embryo of, 332 ; pro-
thallium of, 329 ; spores of, 328.

Sanio, observations on spores of Equi-
setacese, 280 ; observations on ab-
normal formation of elaters in Equi-
setaceae, 291.

Sarcoscyphus Funkii, germination of,
54; ramification of prothallium of,
84.

Savi, on the fecundation of the macro-
spores of Salvinia, 334.

Scalariform-cells and vessels of Pteris
aquilina, 219, 220.

Scales of Aspidium filix-mas-, 242 ; of
Isoetes lacustris, 346, 303 ; of Ma-
rattia cicutcefolia, 255 ; of Nipho-
bolus rupestris, and N. splendens,
249; of Polypodium vidgare, 251.

Schacht on Anthoceros, 19 ; on adventi-
tious buds in Botrychium, 310; on
the formation of the embryo in Coui-
ferse, 428 ; on the pollen of Ephedra,
406 ; on the archegonia of ferns,
200; on the spermatozoids of ferns,
199 ; on the development of the
spore-mother-cells of ferns, 250 ; on
spermatozoids of Pelliaepiphylla, 31.

Schimper on the archegonia of mosses,
177 ; on the germination of mosses,
170; on the spermatozoids of mosses,
177 ; on the antheridia of Sphag-
num, 177 ; on pitted cells in Sphag-
num, 134 ; on the pro-embryo of
Sphagnum, 174 ; on ramification in
Sphagnum, 138.

Schistostega osmundacea, pro-embryo
of, 172.

Schleiden on buds of Aspidium fllix-
nias 245 ; on the formation of the
embryo in Coniferae, 428 ; on the
pro-embryo of Coniferae, 432 ; on
the exosporium of Isoetes lacustris,
338 ; on the sporangia of Isoetes

lacustris, 364 ; on the leaves of
mosses, 147 ; on the spores of
Bhizocarpeae, 335 ; on the anthe-
ridia of Sphagnum, 155, 177.

Schmidel on the elaters of Aneura mul-
tijida, 80 ; on Fegatella conica, 115,
123 ; discovery of spermatozoids in
Fossombronia pusilla, 87 ; on Mar-
chantia polymorpha, 123; on Preissia
commutata, 123 ; on the fructifica-
tion of Biccia, 97-

Scolopendrium officinarum, Morison's
observations on the growth of, from
spores, 257.

Selaginella, germinatiou of, Mettenius
on, 337 ; growth of young plants of,
396 ; production of spores of, 388.

Selaginella cordifolia, furcation of
stem of, 381.

Selaginella denticulata, 374.

Selaginella Galeottii, furcation of stem
of 381 ; growth of 373.

Selaginella Helvetica, 374 ; free deve-
lopment of microspores of 394 ;
spermatozoids of 395 ; furcation of
stem of, 381 ; formation of sporangia
in, 385.

Selaginella hortensis, growth of, 373 ;
macrosporangia of, 387 ; formation
of sporangia in, 385 ; furcation of
stem of, 381.

Selaginella Martensi, 374; marginal
papillae of leaves of, 380 ; furcation
of stem of, 381.

Selaginella viticulosa, 374 ; furcation
of stem of, 381.

Shoots, adventitious, of Equisetacea;,
277; half-subterranean of Haplomi-
irium Hookeri, 64 ; of Jungermannia
bicuspidata, 64 ; of Marchantieae,
102 ; adventitious, of Metzgeria
furcata 42 ; of Pellia epiphylla, 25 ;
Riella Reuteri, 99 ; laterals of
Sphagnum, 137; of Targioneae, 102.

Sori of ferns, 250.

Spach on the pro-embryo of the Coni-
ferae, 433.

Spermatozoids of Archidium, Thuret
on, 109; of Equisetaceae, 294 ; de-
scribed by Milde, 306 ; of ferns,
187 — 1S9; discovered by Nageli,
258 ; observations on, by Thuret,
259 ; of Fossombronia pusilla, 67 ;
discovered by Schmidel, 87 ; of
Frullania dilatala, 67 ; of Funaria
hygromelrica,l54i; of Isoetes lacus-

INDEX.

505

trjs, 312 ; of Juugermannise, 67 ;
Gottsche on, 87 ; of Madotheca pla-
typhylla, 67 ; of Marchantia poly-
morpha, 121 ; first noticed by Unger,
127; Thuret on, 128; of mosses,
Unger on, 176 ; Schimper and
Thuret on, 177 ; of Pellia epiphylla,
30; observations on, by Schacht
and Thuret, 31 ; production of, by
small spores of Pilularia, 323 ; ob-
served by Nageli, 335 of Poly iri-
dium formosum, 151; of Selaginella
Helvetica, 395 ; of Sphagnum, 155 ;
of Salviuia nutans, 331.
diagnum, antheridia of, 151 ; pitted
cells of, 131 ; development of fruit
of, 159; development of leaf of, 135 ;
ramification of, 137 ; growth of
stem of, 129 ; spermatozoids of,
185; terminal bud of, 129.
ihagnum acutifolium, leaf of, 143.
ihagnum cuspidalum, pro-embryo of,
171.

ihagnum cymbifolium, development of
fruit of, 159.

ihagnum squarrosum, development of
fruit of, 159 ; cells in leaves of,
112.

lorangia, of Equisetum, formation
of, 281 ; of ferns, 256 ; of Isoiites la-
custris, formation of, 361 ; Schleiden
on, 361; of Pilularia, development
of, 318 ; of Selaginella, production
of, 385 ; views of Bischoff and von
Mold on, 387.
tore mother-cells of Aneura multifida,

15 ; of Anthoceros, 11 — 17 ; von
Mold on the formation of septa in,

16 ; of Blasia pusilla, 82 ; of Equi-
setum, 282 ; of ferns, 256 ; of Fos-
sombronia picsilla, 82 ; of Frullania
dilatata, 81 ; of Isoiites la custris,
365 ; of Jungermaunia bicuspidala,
78, 79, 81; of mosses, 160; of
Pellia epiphylla, 38 ; of Pilularia,
319 ; of liiccia glauca, 96;' of
Puella, 100; of Targionia hypo-
phylla, 120.

)ores of Anthoceros, 13, 17, disper-
sion of, IS ; of Equisetacese, deve-
lopment of, 2S3, 290 ; Sanio's obser-
vations on, 2S6 ; germination of,
291; of ferns, 182, 256; of Fnd-
lania dilatata, germination of, 51 ;
of Gymnostomum pyriforme, 167 ; of
Isoeteae, Mettenius on, 337 ; of Jun-

germannia, von Mold on the deve-
lopment of, 86 ; observations on
the germination of, by Hedwig,
Nees von Esenbeck, Bischoff,
Gottsche, and Gronland, 83, 81 ; of
Jungermannia bicuspidata, germina-
tion of, 52 ; of Marsilea pubescens,
germination of, 326 ; of mosses,
Hedwig on, 175 ; of Pellia epi-
phylla, 21 ; . development of, 39 ;
their importance in the study of
cell-formation, 39 ; irregularities
in, 11 ; of Phascum cuspidatum,
161 ; of Pilularia, development of,
319; germination o f large, 321; pro-
duction of spermatozoids by small,
323 ; of Radida complanata, 55 ;
of Bhizocarpese, Schleiden's opi-
nions on, 335; of Puella, 100; of
Salvinia natans, 328, 330 ; Met-
tenius on, 330 ; production of Sper-
matozoids by small, 331 ; of Sela-
ginella, production of, 338.

Stem, of Anthoceros, 3 ; arrangement
of cells in, 1 ; of Aspidium filix-mas,

■ 227 ; of Blasia pusilla, 17 ; of
Equisetacese, growth of, 267 ; of
Equisetum, structure of, 271 ; of
ferns, growth and bifurcation of,
262 — 26l ; Pringsheim and Irmisch
on, 264 ; structure of, described by
Von Mold, Brogniart, Stengel,
262 ; Karsten and Mettenius, 263 ;
of Isoetes lacustris, structure of, 356,
357 ; development of, 361 ; of Mar-
chantiese, 110 ; of Orthotrichum
affine, 139 ; of Pilularia, 325 ; of
Pteris aquilina, growth of, 211 ;
cellular hairs of, 212 ; structure of,
213 ; of Selaginella, furcation of,
375, 3S0 ; of Sphagnum, cell-multi-
plication in, 130 ; growth of, 129.

Stem-bud of Aspidium jiUx-mas, 227 ;
of Pteris aquilina, formation of
vessels and bast-cells in, 217

Stengel on the stems of ferns, 216.

Stigma, so-called, of Mosses, 151.

Stipule, of Marattia cicutcefolia, pro-
duction of, 254; of Ophioglossum
vulgatum, 313; of Selaginella, first
observed by R. Midler, 378.

Stolons of Nephrolepis, 217.

Stomata, of Marchantiepe, 110; of
the antheridal discs of Marchantia
polymorpha, 121 ; of the receptacle
of Marchantia polymorpha, 117.

53

506

INDEX.

Struthiopteris germanica, adventitious
shoots of, 247; vegetation of, 245.

Suspensor of Coniferse, Hartig on, 433.

Sympodium of Pteris aquilina, 224,
225.

Targionia, 102.

Targionia hypophylla, arcliegonia of,
118 ; calyptra of, 119 ; elaters of,
120 ; fruit of, 119 ; development of
leaves of, 110; spore-inother-cells
of, 120; vegetative organs of, 102.

Taxus, corpuscula of, 410 ; develop-
ment of endorsperm of, 409 ; fecun-
dation of, 422 ; nucleus in, 400.

Thuja, corpuscula of, 410; develop-
ment of endorsperm in, 410; nucleus
of, 400.

Thuya occidentalism cell-division in an-
thers of, 404.

Thuja orientalis^ fecundation of, 424.

Thuret, on the spermatozoids of Archi-
dium, 169 ; observations on the
antheridia of Equisetaceee, 306 ; on
the spermatozoids of ferns, 189,
259 ; on Marchantiese and their
motile spermatozoids, 128 ; on the
spermatozoids of mosses, 177 ; on
the spermatozoids of Pellia epi-
phylla, 31.

Trichocolea tomentella, cell-multiplica-
tion in stem of, 56. »

Unger, motile spermatozoids first seen
in Marchantia by, 127 ; on the
spermatozoids of mosses, 176 ; on

fructification of Riceia, 97 ; on the
antheridia of Sphagnum, 177.

Vaginula of mosses, 189.

Valentine on the archegonia of mosses,
177 ; on the reproduction of mosses,
178.

Vascular-bundles of the stem of Aspi-
diumfilix-mas, 228, 229, 230, 231 ;
formation of, in stems of Equisetum,
273 ; production of, in Isoiites lacus-
tris, 352 ; of stem of Niphobolus,
251 ; of Ophioglossum vulgalum,
314; of the stem of Platycerium
alcicorne, 253 ; of the stem of Poly-
podium aureum and P. vulyare, 251 ;
in the stem of Pteris aquilina, 213 ;
in the stipes of fronds of Pteris
aquilina, 215 ; arrangement of, in
frondless shoots of old plants of
Pteris aquilina, 225 ; of Salvinia
nutans, 334 ; of stem of Selaginella,
382.

Vaucher, observations on the germina-
tion of Equisetaceae, 304.

Vegetation of Isoetes, compared with
that of other vascular cryptogamia,

371.

Vessels, formation of, in stem-bud of
Pteris aquilina, 217 ; scalariform,
of Pteris aquilina, 220.

Wigand, on the growth of the second
frond in ferns, 207 ; observations on
the impregnation of ferns, 259 ; on
the roots of ferns, 203 : on the
spermatozoids of ferns, 187.

PRINTED BY J. E. ADLARD, BARTHOLOMEW CLOSE, LONDON.

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