BRITISH
FRESH- WATER ALG^E.

VOL. I.

>

<

BRITISH

FRESH-WATER A.LGM.

EXCLUSIVE OF

DESM1DIE.E AND DIATOMACE^E.

BY

M. C. COOKE, M.A., LL.D., A.L.S.,

Author of "Handbook of British Ftniyi," " Mycographia" "Illustrations

of British, Fwuji" \c., \c.

VOL. I. TEXT.

WILLIAMS AND NORGATE,

HENEIETTA STEEET, COVENT GAEDEN, LONDON;

SOUTH FEEDEEICK 8TEEET, EDINEUEG-H.
LEIPZIG : F. A. BEOCKHAUS. NEW YOEK : WESTEEMANN & CO.

1882—1884.

R

BBITISH FEESH-WATEB

INTRODUCTION.

" Fresh-Water Algee J: is confessedly an artificial arrange-
ment which demands apology, but can scarcely receive
justification. The -only excuse which can be offered is, that it
serves the purpose of those for whom the present work was
written, namely, the Microscopists who desire some acquaint-
ance with the organisms met with in their excursions to ponds
and ditches. For the absolutely scientific algologist it will
only be fragmentary, although it is by no means a solitary in-
stance in which the Fresh-Water Algaa have been made the
sole subject of a book, to the exclusion of marine species.
Indeed, the restriction of Harvey's " Phycologia Britannica '
to marine algse, with but very few exceptions, left at least an
excuse for attempting to supply the deficiency.

The historical portion of this introduction may be speedily
summarized by dividing it into three epochs of about forty years
each, the first being limited by the publication of Dillwyn's
" Confervas," the second by Hassall's " Fresh-Water Alga3,"
and the third by the present work.

Prior to the first epoch there were but two works of sufficient

60250

l INTRODUCTION.

importance to be mentioned here, Ray's " Synopsis," which
was published in 1724, and Dillenius' " Historia Muscoruin '
in 1741. Each of these, as far as they can be identified,
included somewhere about twenty species of Fresh-Water
Algaa.

The epoch commences in reality witli Hudson's " Flora
Anglica," the first edition of which is dated 1762, and contains
about 25 species. Then came the first Edition of Withering's
" Arrangement of British Plants ' in 1776 ; Lightfoot's
"Flora Scotica ': in 1777, also witli 25 species; Robson's
"British. Flora" in the same year, with 26 species; the
second Edition of Hudson's " Flora Anglica " in 1778 ;
Relhan's " Flora Cantabrigensis " in 1785, with 12 species ;
and Sibthorp's " Flora Oxoniensis ' in 1794, with 7 species.
This brings us to the third Edition of Withering in 1796, with
38 species ; followed by Abbot's " Flora Bedfordiensis ': in
1798, with 14 species ; and Hull's " British Flora " in 1799, with
34 species. These were all the predecessors of Dillwyn, and did
not achieve much for the Fresh- Water Algte until the climax
was attained by the publication of Dillwyn's " British Con-
fervas' in 1809, with 88 species enumerated. The first Edition
of " English Botany ' had already commenced in 1790, ex-
tending to 1814, but it was not until after the appearance of
Dillwyn's work that the Alga3 of the British Botany were
published, ultimately including about 100 species. Undoubtedly
Dillwyn was therefore the parent of a systematic study of the
British Fresh-Water Alga3, and with him the first epoch
culminated.

The second epoch commenced well with the continuance of
" English Botany," and then followed several Botanists whose
influence has passed down even to our own times. Following
the example of the first epoch, we may enumerate the most im-
portant of their works. The " Midland Flora " of Purton in
1821 only includes about 14 species. Hooker's " Flora
Scotica'' in 1821 about 39 species; Gray's " Arrangement "
in 1824, was confessedly devoted chiefly to systematic classifica-
tion, including nominally 103 British Fresh-Water Algse,
Greville's " Flora Edinensis ' in 1824 had 50 species, the

INTRODUCTION. Ill

working period for Alga? having scarcely commenced, his
" Algas Britannicse " appearing in 1830. Jones and Kingston's
te Flora Devoniensis " in 1829 included but 29 species. John-
ston's "Flora of Berwick-on-Tweed" in 1831 had 40 species.
Near this time (1833) Berkeley's "Gleanings of British
Algse "' was published. The latter volumes of " The English
Flora'3 appeared also in 1833, under the editorship of Sir
William Hooker, the Alga3 being contributed by Dr. W. H.
Harvey, and included 160 species. This was Harvey's first im-
portant contribution to the History of British Alg£e, which was
succeeded in 1841 by the first Edition of his " Manual," con-
taining 198 fresh water species. Between these two Mackay's
" Flora Hibernica ' was issued in 1836, with 87 Irish species.
These all culminated, in 1845, in the appearance of Hassall's
" Fresh- Water Algaa," enumerating 297 species, exclusive of
Characese, Desmidiaceaa, and Diatomaceas, thus closing the
second epoch. The time at which this latter work appeared was
an active one in British Fresh-Water Algse. Ralfs was preparing
his work on Desmids, and contributing papers to the scientific
journals, notably the " Annals of Natural History." Dr.
Greville had commenced his " Scottish Cryptogamic Flora '' in
1823. Harvey was at work earnestly with Marine, and of course
casually with Fresh- Water Algre. The volume containing the
Algae of the 'l English Botany," second Edition, appeared in
1844, so that about this time, which we distinguish as the end
of the second epoch, characterised by the publication of
Hassall's work, there was greater promise than came to be rea-
lized in the early part of the next epoch.

It is not uncommon to hear observations made disparagingly
of the work with which the second epoch closed, when no
account is taken of the difficulties which had to be encountered
in preparing an illustrated work of that nature. It cannot be
fair to judge it by its successors, but by its predecessors, and if
it was fairly up to the general standard at the time of its pro-
duction, that is all we can expect. It must be remembered that
Kutzing's large and splendid work, the " Tabulae Phycologias?,"
was only commenced in 1846, and that therefore it could not be
consulted. It is certainly to be regretted that in Hassall no
indication is given of the measurement of the objects figured, or

IV INTRODUCTION.

tlie magnification employed. That there are faults no one will
deny ; but, on the whole, we are not prepared to condemn it as
unworthy of the time at which it appeared. A comparison of
the Desmids with those in Ralfs' work, of but three years
later, will show that in execution something was left to be
desired.

The third epoch is one on which we must necessarily be very
brief; coming so near our own time we must be content to in-
dicate what has been done, and leave conclusions to others.
Closer relations with the Continent, cheap postage, more general
acquaintance with foreign works, all tend to raise greater expec-
tations for the closing work of the third epoch than of its pre-
decessors. The works of Kutzing, the Memoirs of Pringsheim,
De Bary, Colin, Bornet, Thuret, Borzi. Wittrock, and many
others, all contribute to illustrate British Fresh-Water Alga? ;
and although during forty years very little has been done in our
own island, even in the identification of species, there has been
considerable activity in investigation, especially in the North of
Europe. The scattered memoranda, notes and observations of
Professor Henfrey, Dr. Braxton Hicks, and Mr. "W. Archer
constitute the bulk of our home manufacture of the literature of
Fresh-Water Alga3 for about 30 years. The later portions of
the " Supplement to English Botany," containing Algre, date
from 1843 ; and Harvey's second Edition of the " Manual," in
1849, was wholly confined to Marine species. Hence there is
not an independent work on British Fresh-Water Algse belonging
to this third epoch, the only contributory work being Berkeley's
" Introduction to Cryptogamic Botany," in 1857. But if there
was an extraordinary dearth of books on this subject after 1845
in Britain, such was not the case on the Continent. The con-
secutive publication of the volumes of Kutzing's " Tabular '
must have been an important influence, although it was not
until 1864 that Eabenhorst's " Flora Europsea Algarum, Aqua?
Dulcis et Submarine " was commenced. The advent of this
work was hailed with pleasure, notwithstanding its many faults;
and various authors set themselves to work on different genera
and families, such as ^Edogoniacea?, Zygnemacea?, &c., so that
in twenty years it is left far behind. As a work written in Eng-
lish, although not containing much original observation, we

INTRODUCTION.

must mention Dr. Horatio Wood's " Fresh-Water Alg£e of
North America," published in 1872. The period selected,
therefore, for a new work on the " British Fresh-Water Algae "
was in all respects opportune, but we are not expected to judge
whether good use has been made of the opportunity.

The gradual accession to knowledge of the structure and
development of Algse, during the past century, would extend
this chapter far beyond the limits we have assigned to it,
whereas an intimation of the present position is generally indi-
cated under the several groups, in the body of the work, with
some reference to the sources of further information.

Classification must, of course, depend very largely upon
investigation, and modifications necessarily follow new facts, so
that, whilst adopting suggestions made by authors of recent
monographs, our arrangement is not absolutely that of any
other work, although as far as possible the orders and larger
groups have not been disturbed. We will not venture to pre-
dict what will be the future of such families as the Palmellacece,
Protococcacece,and Chroococcacece during the next twenty years;
probably they will disappear altogether, becoming merged into
other groups of which most of them may be demonstrated to be
only imperfect conditions. At the present time we could follow
no other course than to include them, and leave the future to
take care of itself. We have preferred including too much to
excluding too much, in confidence that for this we should be
the more readily forgiven.

The student will expect to find in this place some practical
hints to guide him in his pursuit, but these must be brief, as
experience, combined with a little personal contact with old
hands at field-work, will supersede a volume of precepts.

The habitats attached to the various species will indicate
the kind of locality in which to search for them, but it may be
remarked that, generally, any slow stream, pond, or standing
pool will furnish something. Rapid currents will not repay the
search. Small pools on moors, amongst Sphagnum, will usually
prove prolific, and submerged plants, especially when dead or
dying, often serve as a habitat for attached species. Damp
rocks, down which the water trickles, old quarries, damp walls

VI INTRODUCTION.

in greenhouses and hothouses, warm springs, outlets of warm
water from steam engines, brackish ditches, all these have their
own peculiar forms, and experience will soon prove that where
the favourable condition of quiet humidity is found, search will
seldom be in vain. Of course, during exceptionally dry
weather localities which would otherwise give satisfaction may
produce nothing but disappointment.

The methods of collecting do not much differ from those
adopted for other kinds of pond life. A japanned case with
from six to twelve corked test tubes will usually suffice for a
day's collecting. Filamentous Alga?, such as S'pirogyra, Clado-
phora, &c., may be wrapped singly in paper, and a number of
these packets can be contained in a small tin box. It is always
essential to keep each " gathering " by itself.

Preservation for future study, or for the herbarium, will be
secured by the usual methods of floating and mounting marine
Alga?, first cleansing the specimens by well washing in a flat
dish or soup-plate, and finally passing under them a slip of
clean white paper, which is raised so as to take up the Alga? in
the middle, well floated into position, draining off the water,
and then drying, with the least pressure possible. For minute
species, and small specimens, thin flakes of mica are preferable
to paper, for many reasons, especially that they can be placed at
any time under the microscope and examined. The Palmel-
lacece, and similar groups, will be of very little service if dried
in any other way. Most species will adhere of themselves to
either paper or mica, the exceptions, such as Vaucheria and some
Cladophorce, can be fixed with gum tragacanth.

Some difficulty may probably be experienced in mounting
satisfactorily specimens for the microscope. We have seen
" slides " in which the specimens were still green and life-like
after having been mounted for twelve years in the water in
which they were collected, but unfortunately there is always a
risk of leakage with mounts in fluid, If the medium is denser
than the contents of the Alga? cells, the endochrome will be
contracted and the walls collapse. One objection to mounting
in glycerine, or glycerine and water, is the density of the
medium, and consequent collapse of the cells ; another, that in

INTRODUCTION. Vll

time, use what precaution you may, the cells will leak, more or
less, in the majority of instances. No medium has yet given
us absolute satisfaction, but all things being considered, we are
most favourably disposed towards glycerine jelly, which is too
dense to enter the cells, and does not alter the form more than
glycerine would do. We may add that the slides should always
\\eflat in the cabinet, and not on edge, and they should not be
left exposed to the light, or the green colour will soon be lost.

Hints for cultivating in growing cells, or preservation in
small aquaria, are scarcely necessary in these days of manipu-
lation. Many forms of growing slides have been designed
and described, each possessing some special advantage, and
arrangements of common glass tumblers, communicating with
each other by small syphons, or lax threads, will keep up a
constant flow of water, sufficient to preserve Algse living and
thriving throughout the year. The life-history, changes, and
development of many species still require to be patiently inves-
tigated, and for this purpose there are ample contrivances, all
that is required being leisure, patience, and perseverance.

It can scarcely be necessary to insist on the presence of fructi-
fication, if a given species is to be accurately determined. This
is especially the case in (Edogoniacece and Zygnemacece, but it
applies also in a less degree to the majority of families. The
great difficulty that is experienced in determining, with any
approximation to accuracy, many of the species described by
authors half a century ago, lies in the insufficiency of the cha-
racters of the fructification. A large number of species of
(Edogoniwn, for instance, as recent as Hassall's work, cannot be
definitely placed on account of this insufficiency. This may at
the same time serve as a caution to the inexperienced, that it
will be worse than useless attempting to affix a name to speci-
mens collected in a young or imperfect condition, at any rate in
genera the fructification of which is known, and embodied in
the generic and specific characters.

Although it can hardly be considered essential to allude in
this place to theories which have been propounded in connection
with Fresh-Water Alg£e, we may make a passing allusion to
the suggestion that sexually distinct filaments exist in the

Vlll INTRODUCTION.

Zygncmacece, and meet it by the assertion that, as far as our
experience goes, this suggestion is not supported, and the
evidence produced is far from satisfactory. The larger and
more complex hypothesis of the combination of Algse and Fungi
in the production of Lichens, has been combated elsewhere,*
and to this we have nothing to add, save that we have since
encountered no facts or arguments which would induce us to
modify that opinion. Even should hereafter the terrestrial
Nostocs be united with the Collemacece, the saxicolous Stigo-
nemece be relegated to the Sirosiphei, and the corticolous
Chroolepidce be transferred to some other relationship, the true
aquatic Alga? would still remain in sufficient number to interest
the student, and maintain for some time to come the distinctive
group of Fresh-Water Alga3.

* " Grevillea," Vol. vii., p. 102.

BRITISH

FRESH-WATER ALGK

Algse are usually associated under five classes, which are
taken invariable order, according to the judgment of the author,
and may thus be enumerated : —

V

I. CHLOROPHYLLOPHYCE^E, with the cell contents mostly of a
chlorophyll green.

II. PHYCOCHROMOPHYCEJS, with the cell contents mostly of a
bluish green.

III. MELANOPHYCE^:, with the cell contents olive, brownish,
or blackish.

IV. RHODOPHYCE^E, with the cell contents rosy, purple,
crimson or violet.

V. DIATOMOPHYCE.E, with an incombustible siliceous skeleton.

Other arrangements have been proposed, but the above will answer for
all practical purposes. The third class are all marine, and the majority
of the fourth, so that, exclusive of Diatoms, which are a special study,
the fresh water Algae are mainly included in the first two classes.

CLASS I. CHLOROPHYLLOPHYOE^J.

Plants aquatic or aerial, one, or two, or many-celled, either
single or associated in families. Either branched or simple.
Cell wall not siliceous but combustible, sometimes composed of
successive layers, or strata, of a gelatinous substance. Cell
contents chlorophyllose, sometimes crimson, flesh-coloured or
reddish-brown, often with a central or lateral nucleus. Starchy
granules very rare. Vegetation by cell division. Fecundation
often sexual. Propagation either by oospores or zygospores or
gonidia, which are motionless or agile (zoogonidia). — Rabh.
Alg. in. p. 1.

* Exclusive of Desmidiese and Diatomaceae.

B

2 COCCOPHYCE.E.

ORDER I. COCCOPHYCEJE.

Unicellular alg^e. Cells either single, or many associated in
families, tegument involute or naked, destitute of branches or
terminal vegetation. Propagation by cell-division or zoogo-
nidia.

This order includes the two families Palmellacece and Protococcacece,
with unmoveable cells, to which is attached a third, the Volvocinece, with
mobile cells. The two former correspond to the Chroococcacece amongst
the class PhycocJiromacece. Although thus removed, it would seem from
recent researches, that there is, in some sort, a relationship between the
Palmellacece and Protococcacea, on the one hand, and the Chroococcacece
on the other.

We can only direct attention here to the papers by P. Richter, in
"Hedwigia,' (xix., 1880, p. 154-) on Glceocystis and (xix. 1880, p. 169
and 191), on the " genetic Connection of certain Unicellular PhycocJi-
romacece" of which abstracts were published in the " Koyal Microsco-
pical Journal."*

The conclusions arrived at are in favour of a sort of polymorphism.

" The lowest form of the Phycochromaceaa is the naked Aphanocapsa
condition, corresponding to Palmella among the Chlorophyllophyceae.
From this naked or only slightly encysted condition is developed the
Glceocapsa or Glceocystis form with several gelatinous envelopes ; the
Chroococcus type, when the investment is altogether wanting, or, when
there is only a single vesicular envelope, the caenobium types. The
Glceocapsa type is specially adapted for exposure to the air, and growth
upon a comparatively dry substratum ; the caenobium type is developed
in water ; the Chroococceus type in water, or on a moist substratum in
the air. With this is connected the cylindrical form, a higher stage,
because it displays a differentiation in the direction of growth, and a
development towards the filiform condition. This is not always de-
veloped, and may be distinguished into stable and unstable forms ; the
latter may occur in two or three varieties, and may go through the
following successive conditions : —

1. — Stable Aphanocapsa and Palmella.

2. — Aphanocapsa and Palmella which have attained to Glceocapsa,
Glceocystis, or Ceenobium type, but which always revert to the naked
solitary spherical form.

3. — Stable Glceocapsa, Glceocystis, Chroococcus, and caenobium forms,
without reversion (Merismopedia).

4. — Cylindrical forms, the generations of which pass through the
solitary spherical fAphanocapga and Palmella} condition, as well as the
Glceocapsa and similar forms.

5. — Cylindrical forms, which pass through only the Glceoeapsa and
similar forms.

6. — Cylindrical forms the generations of which revert to the Apliano-
capsa and Palmella condition, while the Glceocapsa or any similar form
is suppressed.

7. — Stable cylindrical forms CSynecliococcus).

No reference is made in the above to the passage of Glceocapsa into
the encysted filiform conditions of Sirosiphon corresponding to Palmo-
dactylon and Hormospora among the Chlorophyllophycese."

* Vol. I., Second Series, 188±, pp. 98 and 201.

PALMELLACE^E. 3

FAMILY I. PALMELLACE^E.

Unicellular algas, in the broadest sense. Cells either solitary,
or more or less numerous, associated in families, vegetating by
cell-division, propagation by gonidia, which are produced from
the ultimate generation of cells. Gonidia, when free, ciliate
(usually with a pair of cilia) actively mobile.

GENUS 1. EREHEOSPHJERA. De Bary. (1858.)
Cells single, rather large, swimming free, spherical, cell wall
firm, with a hyaline border. Cell contents (Gytioplasma} green,
granulose, sometimes containing green lamina disposed in a
radiate manner. Multiplication of the cytioplasm by division
into two or four (or more) sister cells, which escape by the
rupture of the cell-wall (Cytioderm.}

Eremosphaera viridis. DeBy. Conj.p. 56, t. viii./. 26, 27.

Cells globose, large, of a beautiful grass green. — Rabh. Alg.
iii. p. 24.

Chlorosphcera Oliveri, Henfr. Trans. Micr. Soc. vii. p. 25
(1859), pi. 3. Kirch. Alg. Schl. p. 115.

SIZE, -0043--0059 in. = -11--15 mm. (Rabh.}, -1--12 mm.
(M.C.C.).

In boggy ditches.

" The ordinary appearance of the plant is that of a large green globe,
like a large spore, lying free in the water, or often gathered in loose
groups upon decaying vegetable structures, such as leaves of Sphagnum
contained in the water. The globe is a single simple cell, with a thin
membranous coat surrounding a mass of usually green granular con-
tents. Each cell produces two, or more rarely, four new ones." —
Henfr ey.

Plate I. Cells in various conditions, all magnified 400 diameters.

GENUS 2. FX.EUROCOCCUS. Meneg. (1842.)
Cells segregated, globose (or angular from mutual pressure),
with a central nucleus. Single or associated in small families
which are either globose or cubical. Cell wall firm, often thick,
even, hyaline. Cell contents homogenous green, or oily red.
Multiplication of cells by division in alternate directions. Pro-
pagation by gonidia in proper cells (Sporangia).
Plants aquatic, or aerial.

* Species green.

Pleurococcus vulgar is. Meneg. Nost. 38, t. 5,/. 1.
Cells variable in size, simple, binate or quaternate, or as many
as 32 associated in families, aggregated in a crustaceous, pow-
dery bright-green and somewhat gelatinous (when moist) stratum.

4 COCCOPHYCEJ3.

SIZE. Cells -004--007 mm. ; fam. -018 mm. (Rabh.}, cells
•004--006 mm. (C).

Rabh. Alg. iii. 24 ; Kirch. Alg. Schl. p. 115.
Protococcus valgaris, Kntz. Spec. p. 199.
Protococcus communis, Kutz. Tab. i., f. 3.
Pleurococcus communis, Desm. Exs. 1, 1203 ; ii. 603.
Hcematococcus vulgaris, Hass. Alg, p. 333, t. 71, f. 5.
Chlorococcum vulgare, Grev. Sc. Cr., Fl. No. 262.

On the trunks of trees, moist walls, &c. Common everywhere
throughout the year.

" Plant of a lively full green colour, spreading very extensively over
the trunks of trees, and staining the fingers on the slightest touch. Gra-
nules very minute, exceedingly numerous, densely aggregated, and form-
ing an uneven surface. They are perfectly free, semi-transparent, and
adhere together in an opposite manner by fours." — Greville.

Plate II. fig. 1. a, natural size ; b, cells X 400 diam.

Fleuxococcus angulosus. (Corda) Meneg.Nost. t.4,, f. 5.

Cells single, or 2-4, associated (04) in families, deep green,
nestling in greenish, rather gelatinous stratum, cell-membrane
thick, diaphanous.

SIZE. Cells -007--013 mm. (Rabh.}.

Rabh. Alg. iii. 25. Kirch. Alg. Schl. p. 115.

Protococcus angulosus, Corda in Sturm Fl. ii. 18.

Microcijstis angulosa, Kutz. Linna3a, viii, 374.

Protococcus palustris, Kutz. Tab. i., t. 4.

On the stems and leaves of aquatic plants.

In the Kew Herbarium copy of Rabenhorst's Algae Exsicc, No. 327,
under this name, only Chroococcus turgidus can be found, so that it is
not quoted above.

Plate II. f. 2. Cells magnified 400 diam.

Pleurococcus (?) mucosus. Rabh. Alg. in. p. 26.

Cells very small, of variable size, single and 4-16, associated
in globose families, scattered, or aggregated in a gelatinous
green stratum. Cell-membrane very thin, hyaline, contents
homogenous, decussately divided; nucleus rounded.

SIZE. Cells •0023--0003 mm. (Rabh.}.

Protococcus mucosus, Kutz. Tab. i., t. 4.

Hcematococcus theriacus, Hass. Alg. p. 333, t. 78, f. 9.

On the naked ground.

Dr. Allmann compares its appearance to inspissated syrup.
Plate 22. Jig. 3. Cells magnified 400 diam.

Pleurococcus Beigelii. Ruch 8f Rabh.

Aerial, very small, very pale greenish, aggregated in numerous
globose families, encircling the hair. Cell-membrane rather
thick, colourless, contents very finely granular, sporangia con-
taining 12-20 gouidia ; nucleus globose.

PALMELLACE.E. 0

SIZE. Cells -006--0095 mm. (Rabh.).
Kab. Alg. iii. 27.

" The chignon fungus.'" Dr. Tilbury Fox, in " Science
Gossip," May 1, 1867.

On human hair used as " chignons."

This organism, which is included by Rabenhorst amongst Algce under
the above name, is rather a doubtf ul production, at least it seems to be
a doubtful alga. The late Dr. Tilbury Fox examined it carefully in
1867 with the following results : —

" If you take a hair on which the parasite exists, and hold it between
yourself and the light, towards the outer half you will see one or more,
perhaps half-a-dozen, little dark knots, the size of pin points, surround-
ing the shaft of the hair ; they are readily felt on drawing the hair
through the fingers ; they are somewhat difficult to detach. Under the
microscope, with a quarter-inch objective, the mass will be seen to be
made up of cellular bodies surrounding the hair. It will be seen that
the mass has the appearance of a fungus growth, of which two distinct
forms are here present, viz., mycelial or filamentose, and sporular or
cellular. The hair is apparently healthy, and if the slide be pressed the
mass will break away from the hair on either side, bringing away with it
more or less of the cuticle, and leaving behind a healthy shaft. The
cells are seen to be of various shapes and sizes. They are from 1-4000
to 1-3000 of an inch, many are like the 'torula' cells developed from
Penicilium. Others are larger, undergoing division very actively. They
may be subdivided into two, three, or four parts, or much more freely.
This indicates the assumption by the parasite of an algal condition. (It
is this form to which the name Pleurococcus Beigelii manifestly applies.)

" In watching the mass on the hair carefully, it is evident that a
number of small cells become detached from the outer or sporular form,
and at once move actively about. These small cells indicate an active
growth by subdivision, and a fruitful source of propagation. Certainly
this variety of fungus, so far described, is the most active growth I have
come across in my researches, and I have been enabled to germinate it
most successfully, so as to set all questions as to its nature completely
at rest. Placed under favourable circumstances in water, the spores
enlarge considerably, and the mycelial filaments increase also, but there
is at this time to be observed a very remarkable occurrence, though not
in all cases. Some of the large cells have become filled with smaller
cells, and in others, in addition to these, processes have been put forth
from the circumference of the walls in a radiating manner ; in other
cases the enlarged cells have two long cilia attached to them, by which
they move about rapidly, whilst a part of the hair previous to this free
from the fungus, has become dotted all over by minute cells similar to
those seen in the interior of the larger ones.

" But more than this, I have observed most distinctly large cells filled
with smaller cells, furnished with exceedingly delicate radiating pro-
cesses, and putting forth pseudopodia. It will here be seen to have
assumed the features of an ameboid body. Nothing could have been
more distinct to myself, and those who were observing with me, than
this peculiar form ; and it seems to me that we have here a pretty com-
plete history of the life of the fungus — namely, the sporular sub-
dividing and assuming an algal form, which in turn becomes ama3bi-
form, and furnishes ciliated cells that supply the earliest condition of
the fungus, scattered over the hair." Further details, with illustrations
are given in the memoir, of which the above is an abstract, to which the
student is referred.

Plate II. f. 4. Cells magnified 400 diam.

i 6 ^ COCCOPHYCE^E.

** Species red or brownish.
Pleurococcus miniatus. (.Kutz) Nag. Einz. Alg. p. 65.

Cells very variable in size, globose, usually single, rarely 2-4
in a family, seated on a broadly effused red stratum, which is
more or less gelatinous. Cell-membrane rather thick, colour-
less, hyaline, contents oleaginous orange.

SIZE. Cells -0037--016 mm. (Kabh.), -0035--015 mm. (Kirch.}.

Rabh. Alg. iii. p. 27. Rabh. Exs. 31, 368, 1777. Kirch.
Alg. Schl. p. 115.

On the walls of conservatories, all the year.

This is one of the species in which Braun has observed the " skinning
off " of the outer cell-membrane.

Nageli ascribes the red colour occurring in many Palmellacece, partly
as a normal, partly as an abnormal phenomenon, to the formation of an
orange-coloured oil in the place of the chlorophyll.* Braun says that
probably all these have the power of retaining their life a long time in
the dried condition ; in the above species at least, he is quite sure of it.
The brownish-red colour often acquired by Protococcus viridis may pro-
bably be explained in the same way.f

Plate II. jig. 5. Cells magnified 400 diam.

Pleurococcus roseo-persicinus. Rabh. Alg. in., 28.

Aquatic. Cells unequal, cloudy, single or binate, tegument
hyaline, collected on a thin, rather gelatinous peach-rose coloured
stratum.

SIZE. Cells -0015--004 mm.

Protococcus roeeo-persicinus, Kutz. Tab. i. t. i.

Clathrocystis roseo-persicinus, Conn, Beitr. iii. (1875), t. 6,
f. 1-10.

Investing submerged aquatic plants.

This very minute species, with cells of a peach colour, is not un-
common about the debris of decaying plants in pools. The cells are
usually agglomerated in spherical or elliptical masses. Certainly not a
good Pleurococcus.

Plate II. Jig. 6. Cells magnified 400 diam.

GENUS 3. GL-2EOCYSTIS. Nag. (1849.)
Cells globose or oblong, either single or 2-4-8, associated in
globose families. Common and special integuments gelatinous,
lamellose. Division in alternate directions. Propagation by

zoogonidia.

The lamellose tegument distinguishes the species of this genus from
Pleurococcus. Its analogue in the Phycochromacefe is Glceocapsa.

* More or less green.
Glaeocystis amp la. Kutz.

Thallus gelatinous, rounded, lobed, dirty green. Cells glo-
bose, or rounded oblong, 2-4-6 (rarely 8), associated in fami-
lies ; tegument colourless, gelatinous, distinctly concentrically
stratose. Contents green, granular.

* Einzelliger Algae, p. 9. f " Eejuvenescence," p. 213, note.

PALMELLACE.E. 7

SIZE. Cells -009- -012 mm., fam. '043--09 mm. (Rabh.).
Rabh. Alg. iii. p. 29. Kirch. Alg. Schl. p. 112, partly.
Gleocapsa ampla, Kutz. Sp. p. 216. Tab. 3, f. 3.
Pleurococcus superbus, Cienk. Bot. Zeit., 20 Jan., 1865, p.
21. Archer Micr. Journ., 1866, p. 63.

Fixed to submerged plants.

Brann states that he has observed an irregular bursting and peeling
off of the outer coat of multicellular families or sometimes of isolated
cells surrounded by manifold coats in this species, and 6f. vesiculosa.*

Plate 111. fig. 1. Cells magnified 400 diam.

Glaeocystis vesiculosa. Nag. Einz. Alg. p. 66, t. 4.

Thallus gelatinous, green ; cells small, globose, as many as
64, and more, associated in families ; tegument hyaline, colour-
less, lamellose, lamellae often breaking up ; contents green,
delicately granular.

SIZE. Cells 0045--0075 mm. ; fam. '036 mm. (Rabh.).

Rabh. Alg. iii., 29. Rabh. Exs., No. 707.

Gl&ocystis ampla var. vesiculosa, Kirch. Alg. Schl. p. 112.

On wood and stones in stagnant water.

In character this species resembles the last, but the cells are smaller.
See also Cienkowski's paper in " Botanische Zeitung " for 20 January,
1865, where this species is figured to the same scale as Glceocystis
ampla.

Plate III. Jiff. 2. Cells magnified 400 diam.

Glaeocystis xupestris. (Lyngl.) Rabh. Alg. in., 30.

Thallus more or less expanded, dirty green, gelatinous, rather
firm ; cells globose, middle-size, associated in families ; tegu-
ment colourless, pellucid, distinctly lamellose, soon diffluent ;
contents green, granular ; sporangia globose, containing from
4-12 gonidia.

SIZE. Cells -0037-'005 mm. ; fam. -06 mm. ; sporang. -085
mm. (Rabh.).

Rabh. Krypt. Fl. Sachs, p. 128. Rabh. Exs. 1790. Kirch.
Alg. Schl. p. 112.

Palmella rupestris, Lyngb. Hyd. 207, t. 69. Hook. Eng.
Fl. v. p. 397.

On rocks, moist walls, and damp earth.

" It occurs as a dirty yellowish gelatinous crust often hanging down
in flakes from the face of the rock." — Carm.

This is not, or only in part, the Hcematococcus rupestris, Hassall (p.
326, t. 82, fig. 1), which is chiefly applicable to Gl&ocapsa polyderma-
tica, K.

Plate VIII. Jiff. 1. Cells magnified 400 diam. a, from wet rocks ;
b, from damp earth.

* See Braun, "Rejuvenescence," Ray Society, p. 182.

8 COCCOPHYCE.E.

.

Glaeocystis botryoides. Ktz. phy. Gen. p. 173.

Thallus gelatinous, soft, sticky, green ; cells minute, globose
and oblong, associated in small families ; tegument colourless,
indistinctly lamellose, contents green.

SIZE. Cells -002--004 mm. ; families -01--018 mm.

Glceocapsa botryoides, Kutz. Tab. 1, t. 20.

On wood, submerged or constantly wet.
Plate III. fig. 3. Cells magnified 400 diara.

** Flesh-coloured, becoming reddish.

Glaeocystis Pasroliniana. (Meneg. Nost, t. W,f. 2.)

Thallus crustaceous, cartilagineous (horny when dry), about a
line thick, flesh colour; cells small, spherical, 2-4-8 associated
in families ; tegument very broad, distinctly concentrically
lamellose ; contents becoming yellowish, granulose.

SIZE. Cells -0037--005 mm. ; families -24 mm. (Rabh.).

Eabh. Alg. iii. 30.

Microcystis Paroliniana, Meneg. Nost. p. 78.

Glceocapsa Paroliniana, Kutz. Tab. i. 36, f. 5.

On rocks constantly wet.

Collected some years ago in Kent by Rev. M. J. Berkeley, and usually
found near the sea.

Plate III. Jig. 5. Cells magnified 400 diam.

Glaeocystis adnata. CHuds,) Nag.

Thallus broadly expanded, gelatinous, firm, yellow-brown ;
cells globose, or oblong; contents brownish-green or brown,
granular; tegument colourless, pellucid, lamellose.

SIZE. Cells -008--013 mm. (Rabh.).

Rabh. Alg. iii. 31.

Tremella adnata, Huds. Fl. Ang. p. 565.

Palmella adnata, Lyngb. Hydro, p. 205, t. 69. Berk. Glean,
p. 40, t. 15, f. 2.

Microcystis adnata, Meneg. Nost. p. 85.

" Forming a thin yellow-brown, suborbicular, depressed stratum on
chalk cliffs, about high-water mark. The individual plants, which are
from 1 -6 lines diam., are but very little thicker in the centre than at the
margin. The surface is rugulose and shining, substance firm, between
gelatinous and coriaceous. In age the plant gradually becomes more
tawny, but at all times under the microscope presents a pale ochraceous
jelly filled with darker granules. Under a moderate magnifier the
granules appear globose, but under a lens with l-25th in. focus pellucid,
globose, colourless vesicles are seen to contain the darker granules, and
these are found to be elliptic. Sometimes the vesicles contain a little
tawny colouring matter, as though the sporules were broken down ; and
frequently the sporules burst through the coat of the vesicle in which
they are contained, and lie free on the general mass." — Berkeley.

Plate III. Jig. 4. a, natural size; b, cells magnified 400 diameters.

PALMELLACE.E. 9

GENUS 4. UROCOCCUS. Hass. (1845.)

Cells large, globose, or oblong, reddish or blood-red ; tegu-
ment thick, gelatinous, concentrically larnellose ; stem thick,
gelatinous, often ringed or annulate.

All the species in this genus are rare, and with one exception confined
to Britain. We are, therefore, compelled to reproduce figures already
published, without measurements or information beyond the original
descriptions.

The peculiar structure of the pedicellate cells is thus described by
Braun : — " The large globular brownish-red or blood-red cells throw off
colourless layers of cell membrane, which appear to be separated by
intermediate layers of softer jelly, whence arises a distinctly concentric
structure of the envelope. But the enveloping layers of Urococcus do
not retain their original form and integrity ; not increasing themselves
in size, they are pushed off on the upper side by constantly succeeding
inner coats, being at first merely attenuated at one side, but subse-
quently, as it seemed to me, actually broken through. Since this emer-
gence from the old coats is always repeated on the same side, a mem-
branous-gelatinous peduncle is produced formed of cups fitted one into
another, so as to give an annularly streaked, apparently shortly articu-
lated aspect. The red cell, which occupies the summit of this peduncle,
sometimes divides, and this of course produces a subsequent dichotomy
of the peduncle. If the periods of the formation of the separate
enveloping layers were known, the age of the little plant, whose
history is preserved in the gelatinous peduncle, might be determined by
the number of rings." — Rejuvenescence, p. 179.

* Stem annulate.
Uxococcus Hookerianus. Hass. Alg.t. 80, f. 4.

Cells globose, or elliptic, variable in size, blood-red, granular,
stem more or less elongated, often divided, densely ringed.

SIZE. Cells -013--06 mm. (Rabh.}.

Rabh. Alg. iii. 31.

Hoematococcus Hookeriaua^ Berk. & Hass. in Hass. Alg. p.
325, t. 80, f. 4.

On chalk cliff, &c.

Plate IV. fi(j. 1. a, cells considerably magnified, after Hassall ; b,
cells further magnified, after liabenhorst.

Urococcus insignia. Hass. Alg.t. 80, /. 6, a. b.

Cells large, globose, blood-red ; stem abbreviated, remotely
annul ated.

Rabh. Alg. iii. p. 31.

Hcematococcus msignis, Hass. Alg. p. 324.

" This very fine species I have never met with in any considerable
quantity. Scattered isolated globules I have frequently met with, and
these occasionally attached to a closely corrugated or ringed mucous
appendage. Each globule is usually surrounded by a single vesicle or
ring ; in some globules, however, there are as many as four or five en-
closing vesicles." — Hassall.

Plate IV. fit). 2. a, b, cells considerably magnified, after Hassall.

c

10 COCCOPHYCE.E.

** Stem without rings.
Urococcus Allmanni. Hass. t. 80, /. 3.

Cells elliptical, blood-red; stem short, rather club-shaped,
colourless, smooth.

Eabh. Alg. iii. p. 322.

Hcematococcus Allmanni, Hass. Alg. p. 322.

In springs at Knares borough.

Plate IV. Jig. 3. «, cells considerably magnified, after Hassall; b,
cells further magnified.

Urococcus cryptcphilus. Hass. t. 80, /. 1.

Cells small, oval, rarely globose ; tegument very large, con-
fluent with the short ringless stem.
Rabh. Alg. iii. p. 32.

Hce?natococcus cryptophila, Hass. Alg. p. 324.
Hcematococcus sanguineus, Harv. Man. p. 181.
Palmella cryptophila, Carm. in litt.

On stalactites lining a cavern in a quartz rock.

" Forms wide patches externally of a brick -red colour, but within
whitish, breaking up easily into the numerous separate portions of
which each mass is formed. The colour resides alone in the granules ;
these terminate the superior extremity of the mucous prolongations,
which are colourless, and arranged almost entirely side by side. The
granules or cells are several times smaller than in U. Allmanni." —
Hassall.

Plate IV. jig. 4. a, cells considerably magnified, after Hassall ; b,
cells further magnified.

GENUS 5. SCHIZOCHLAMYS. Br. (1849.)

Cells globose (or ovate), either single, or 2-4 associated in
families ; tegument lamellose, as age advances dividing regularly
in 2-4 equal parts, some time adhering by means of a hyaline
colourless mucous. Division in one or two directions. Zoo-
gonidia produced by a repeated division of the cell contents.

At present represented in Europe by a single species.

" The globular cells of this little Alga produce a hyaline cell-mem-
brane, which becomes removed to some distance from the green body
of the cell by subsequent secretion of fluiclish jelly ; soon, however
(probably from endosmose), becoming unable to withstand the expan-
sion of the jelly, it splits in the direction of an equatorial circle, by a
clean line, into two similar halves, or if the dehiscence takes place by
two circular lines, cutting at right angles, into four similar pieces.
This splitting and peeling of the membrane either coincides with a
division of the internal cell-mass, or it occurs without any such division.
By frequent repetition of this process the cell gradually becomes
surrounded by an accumulation of old fragments of the membranous
shell, which are held together by the extremely transparent jelly set
free. The division of the cell may be either a simple halving, in which
case each part is immediately clothed again with a hyaline cell-mem-
brane, or double, through the cells produced by the first division sepa-

PALMELLACE.E. 11

rating immediately into two cells, without previously acquiring a coat
of cell-membrane, and therefore without skinning." — Braun Rejuvenes-
cence, p. 181.

Schizochlamys gelatinosa. Br. in Kutz. Sp. p. 891.

Cells globose ; contents green, granule se.
SIZE. -01--0135 mm. (Rabh.).

Kutz. Tab. vol. vi. t. 70. Braun Rejuvenescence t. 2, f. 43-
50. Rabh. Alg. iii. 32. Rabli. Exs. No. 103.

In peaty swamps, moor pools, and boggy ditcbes.
Plate III. Jig. 6. Cells magnified 400 diam.

GENUS 6. FALMELLA. Lyngb. (1819.)

Cells globose, oval, or oblong, surrounded with a more or less
thick integument, generally very soon confluent into a firm or
soft jelly. Thallus shapeless. Division of the cells alternately
in all directions.

* Mostly green.

Falmella xnucosa. Kutz. Pkyc. Gen. p. 172.

Thallus expanded, gelatinous, deformed, olivaceous-green ;
cells large, nearly equal, pale green, delicately granular ; tegu-
ment very thin, soon diffluent.

SIZE. Cells -015 mm. (Rabh.), -007--OH mm. (Kirch.).

Rabb. Alg. iii. 33. Kirch. Alg. Schl. p. 110.

Merettia mucosa, Trevis. Alg. p. 46.

On stones in streams.
Plate V. Jig. 1. Portion of thallus with cells magnified 400 diam.

Falmella hyalina. Breb. Alg. Fal. p. 39.

Thallus gelatinous, irregularly expanded, green ; cells very
minute, crowded ; tegument almost homogenous with the gela-
tinous thallus, very soon diffluent.

SIZE. Cells -0005--001 mm. (Rabli.), -00075-'001 mm.
(.Kirch.].

Rabh. Alg. iii. 33. Rabh. Exs. 1525. Kirch. Alg. Schl.
p. 110.

Coccochloris liyalina, Meneg. Nost. p. 66.

In stagnant water, and bogs.

The species called Coccochloris hyalina by Hassall (p. 315) is ffomalo-
coccus Hassallii, Kutz., one of the Phycochromophycece, and not the
present. Perhaps the two may have been mixed up.

Plate V.Jig. 3. a, part of thallus, X 400 ; 6, portion X 800 di

12 COCCOPHYCE^E.

Palmella Moore ana. Harv. Man. p. 178.
Thallns irregularly globose, tuberculate, dark green, gelati-
nous, firm. Cells nearly equal, pale green.
SIZE. Cells -008 X 005 mm.
Rabh. Alg. iii. p. 34.
Coccochloris Mooreana, Hass. Alg. 316, t. 78, f. 1.

In bogs and stagnant water.

" The fronds are of an irregular globose form, about an inch in
diameter, tuberculated, and inclining to become hollow in the centre
when old, at which time it floats on the surface ; the colour is dark-
green and the substance firm, resembling that of an animal's liver." —
Moore.

We found this species floating freely in a pond in Sntton Park, Bir-
mingham. In this condition it has jnst the appearance and texture of a
Nostoc. Is it distinct from Aphanothece prasina ?

Plate V. fig, 4. a, plant natural size ; 6, portion X 400 diaua.

** Reddish or orange.

Palmella miniata, var. sequalis. Nag. Einz. Alg. t. 4, D. 2.

Thallus expanded, soft, amorphous, brick-red ; cells nearly
equal, tegument somewhat thick, colourless, hyaline, indistinctly
striate ; contents orange, sometimes greenish.

SIZE. Cells -012--014 mm.

Rabh. Alg. iii. 34. Rabh. Exs. No. 1778.

Sorospora grumosa, Hass. Alg. p. 310, t. 80, f. 7. ?

On wet rocks, moist ground, &c.

We are of opinion that this is the Sorospora grumosa of Hassall. The
typical form of Palmella miniata has very minute cells, not exceeding
•0035-'004 mm., but this variety, if it be not a distinct species, has cells
nearly four times as large.

Plate V.fig. 2. Portion of thallus, magnified 400 diam.

Palmella prodigiosa. JMont. Comptes Rend. 1852, 119.

Thallus more or less expanded, blood- red, as age advances
moist, or sometimes dripping ; cells very minute, globose,
crowded.

SIZE. Cells -00075--001 mm. (Rabh.).

Rabh. Alg. iii. 34. Stephens, Ann. Nat. Hist. 2 Ser. (1853),
xii. 409. Berk, in Gard. Chron. 1853, p. 515.

Monas prodigiosa, Ehrb. Monat. Berl. 1848.

Zoogalactina imetropha, Sette. Mem. Ven. 1824.

On rice, bread, potatoes, &c.

In the time of Ehrenberg this was considered a minute animal, and
•was included amongst Monads. The blood-red spots which it forms on
bread, rice, potatoes, and other mealy substances, caused great alarm in
more superstitious times. Until very recently opinions were by no
means settled on this subject. The Rev. M. J. Berkeley held it to be a
condition of fungoid life, and in his "Introduction"* he says, "Pal-
mella prodigiosa, from its peculiar habit, seems rather to indicate
affinity with fungi. The rapidity with which it spreads over meat,

* " Introduction to Cryptogamic Botany," p.

PALMELLACE^E. 13

boiled vegetables, or even decaying Agarics, is quite astonishing, making
them appear as if spotted with arterial blood ; and what increases the
illusion is, that there are little detached specks, exactly as if they had
been squirted in jets from a small artery. The particles of which the
substance is composed have an active molecular motion, but the mor-
phosis of the production has not yet been properly observed, and till
that is the case it will be impossible to assign its place rightly in the
vegetable world. Its resemblance to the gelatinous specks which occur
on mouldy paste, or raw meat in an incipient state of decomposition,
satisfy me that it is not properly an Alga." Mr. H. O. Stephens, on
the other hand, contends that it is an Algoid production. After nar-
rating its history (see "Ann. Nat. Hist.," 1853, p. 409), he says — "I
observed at table the under surface of a half-round of boiled salt beef,
cooked the day before, to be specked with several bright carmine-
coloured spots, as if the dish in which the meat was placed had con-
tained minute portions of red currant jelly. On examination the next
day, the spots had spread into patches of a vivid carmine-red stratum of
two or more inches in length.

" With a simple lens the plant appears to consist of a gelatinous sub-
stratum of a paler red, bearing an upper layer of a vivid red hue, hav-
ing an uneven or papillate surface. The microscope shows this stratum
to consist of generally globose cells immersed in or connected by muci-
laginous or gelatinous matter. The cells vary in size, and contain red
endochrome. As far as I can observe they consist of a single cell-
membrane, and contain a nucleus. Treated with sulpho-iodine, they
become blue. In my judgment this plant is a Palmella closely allied to
P. cruenta, but certainly distinct, the cells or granules of the latter
differing from it not only in their colour but size." The memoir also
contains observations on the great vitality of this species, and other
subjects connected therewith, to which the student is referred.

Plate V.fig. 5. a, part of thallus, magnified 400 diam. ; b, portion
magnified 800 diam.

GENUS 7. PORPHYRIDIUM. Nag. (1849.)
Thallus between gelatinous and membranaceous, somewhat
incrusting, long and broadly expanded, composed of globose or
many-sided cells. Multiplication of the cells by alternate di-
vision in all directions. Propagation unknown.

This genus is placed by some authors in Porpliyracece, near the genus
Pangia, in the class Rhodophycece (see Rabh. Alg. iii. 397), but we prefer
to retain it near the old genus Palmella, in whicb it was previously in-
cluded, and to which it seems to be most naturally allied.

Porphyridium cruentum. Nag. Einz. Alg. t. 4 H.

Thallus dark purplish-red, gelatinous ; cells angular or
rounded.

SIZE. -007--01 mm. (Rabh.), -0965--009 mm. (Kirch.).

Kirch. Alg. Schl. p. 111. Rabh. Alg. iii. 397.

Palmella cruenta, Ag. Syst. p. 15. Kabh. Exs. No. 14 and
1071. Hass. Alg. p. 308, t. 80, f. 5.

Tremella cruenta, Eng. Bot. t. 1800. Grev. Sc. Crypt. Fl.
pi. 205.

On the naked ground, moist walls, &c. Common throughout
Europe.

14 COCCOPHYCEJS.

The red spots are at first rounded, then irregular, soon confluent, and
form an expanded crust, like coagulated blood of a deep purple colour.

Plate V'Jig- 6. a, plant natural size ; b, cells magnified 400 diam.

GENUS 8. BGTRYDXNA. Breb. (1839.)

Cells oblong or rounded, involved in a very thick, gelatinous,
partially diffluent integument, in large families, which are often
very numerous, enclosed in a mother cell which constitutes a
subglobose thallus.

Only one species in this genus.

Botrydina vulgaxis. Breb. in Hass. Alg. 320.

Thallus minute, rarely larger than the head of a pin, glo-
bose, green.

SIZE. Thallus from 1 -500th to l-10tli mm. ; cells '002--004
mm.

Meneg. Nost. p. 98, t. 13, f. 2. Rabh. Alg. in. 37. Rabh.
Exs. No. 388. Hass. Alg. p. 320, t. 81, f. 2. Kirch. Alg.
fcchl. p. 111.

On moist ground, trunks, moss, &c.

" The fronds of various sizes, rarely surpassing the head of a pin, of
a subsphaerical form, aggregated in considerable quantity, cover the
stems of mosses with a pulverulent blackish-green stratum, which
Agardh first well delineated. The granules, in the beginning solitary,
here and there affixed, snbsphaerical, or slightly angular, scarcely equal
in their greatest diameter l-500th mm. ; gradually they increase in size,
and when they have arrived at the 1 -200th mm. they manifest an in-
ternal granular substance ; at a later period having acquired a form
exactly spherical, the internal substance is seen aggregated or collected
into the centre, and the granules surrounded by a pellucid margin.
j^gain, they increase in size, and the interior grannies are seen con-
verted into vesicles filled with lesser granules. These vesicles in-
creased in number and magnitude, tho greatest dimensions of the frond
being attained, occupy its entire substance, and at length the diapha-
nous margin disappears. The whole frond is then constituted of vesi-
cles closely heaped together, and enclosing granules in the centre. The
primitive membrane, enclosing in its midst the interwoven or cellular
structure, is so closely united with the peripheral stratum of vesicles,
that it can in no way be separated from it. The last development hav-
ing been accomplished, the peripheral stratum of vesicles altogether
loosens its granules ; whether these disappear by absorption or escape
outwardly, I have never been able to perceive. In this manner the
frond again obtains a diaphanous margin, but different from that with
which, in the beginning, it was surrounded." — Nenegliini.

Plate XI. fig. 3. a, thallns magnified 400; &, cells further magnified.

GENUS 9. FAX.MODICTYON. Ktz. (1845.)
Cells oval or globose, with a very thick gelatinous integu-
ment, united into a filiform thallus, which is connate or anasto-
moses in various ways. Cell division simple or double (de-
cussate). Propagation by zoogonidia from the ultimate gene-
ration of cells.

1'ALMELLACE.E.

15

Palmodictyon viride. Kutz. Tab.Phy. I. t. 31, /. 1.

Thallus mucous, irregularly reticulate, about the thickness
of a hair, greenish ; cells biserial, with a very thick homoge-
nous tegument.

SIZE. Cells without tegument, -0075--009 mm., with the
tegument '025-'04 mm. (Rabh.).

Ilabh. Alg. iii. 37. Kutz. Phy. Germ. p. 155.

In ditches, canals, &c., attached to stones, twigs, &c.

Eecently found by Mr. E. Parfitt near Exeter, of which he gives the
following account : — " The plant, where it has sufficient room to develope
itself, spreads over the bottom, in water about six inches deep ; beyond
this it comes in contact with Elodes canadensis, over which it creeps, and
extends its growth from branch to branch into deeper water. In this
extension it has first the appearance of a Conferva, which I at first took
it to be ; but the moment I touched it, after taking some from the
water, I found from the soft slimy feel that if a Conferva it was new to
me, and the mici'oscope soon revealed the true character. When the
plant grows on the bottom it shows one continuous green membrane,
stretched tight over the bottom, but when it comes in contact with other
plants it throws out filaments, the thickness of which is difficult to make
out on account of their adhesive nature ; for wherever they touch it is
matter of impossibility to separate them. The membrane forming the
filaments is structureless, but the sphserical cells, which form more or
less moniliform threads, sometimes running in parallel lines, at other
times forming an irregular net-work on the inside of the filaments.
These cells sometimes divide into two portions, at others into four, and
in most of the mature cells may be observed four cellules." — Grevillea,
iii., p. 29.

Plate VIII. Jiff. 2. a, portion magnified 200 diam. ; 6, fragment

magnified 400 diam.

Palmodictyon rufescens. Kutz Spec. 234.

Is usually referred here on the faith of the remark by Kutzing, that it
was found at Aberdeen by Dr. Dickie. Upon enquiry of Dr. Dickie we
learn that he knows nothing of the species. He says, " Palmodictyon
rujescens is unknown to me, many years have passed since I corres-
ponded with Lenormand, and I do not remember receiving any note
from him regarding it. Kutzing (Spec. 234) is responsible for the name.
I cannot find in my collection anything so named, neither do I re-
member where the so-called material was collected." Under these cir-
cumstances it is useless repeating the name in connection with British
Algae.

GENUS 10. TETRASPORA. Link. (1810)

Thallus gelatinous, membranous, or submembranous, in the
beginning a short sac, afterward expanded ; cells globose or
angular, more or less distant, but associated in a single stratum
into large families. Tegument thick, very rapidly diffluent into
a homogenous mucous. Division in two directions in the same
plane.

l<i COCCOPHVfK.E.

Tetraspora bullosa. Ay. Sp. Alff. p. 414.

Thullns membranaceoas, saccate, ohovate, sinuate, bullose,
an inch to a palm long, dark green, more or less verrncose ;
cells nearly sph.erical (after division hemisphfierical or angular),
geminate, or quaternate, crowded, granular.

SI/K. Cells before division -(M)8-'012 mm., after division
•005H--0075 mm. ( AV/>/,.).

liabh. Alg. iii. ;;:». llahh. Exs. No. 115, 1233. Kirch.
Alg. Sclil. p. 1«>8.

Monotri'iiui hiillnftum, Thur. Mem. Chorh. 1854.

Ti tr<i*/)'ii'(i minimi, l)esv. Fi»r. Aug. p. 17.

Ulra bnlhs.i, Roth. Cat. iii. 820. ll.ok. Brit. Fl. ii. 31:2.
llsn-v. Man. p. 171. Ha-. Alg. t. 7*, f. 13, Dicki" Bot,
<-iiide, p. 3«n;. Eng. Bot. ed. L'. t. 2405,

Stagnant pools and ditches of fn-^h water.
Plate VI. Ji</. 1. a, uatuial size ; If, frai'iiicnt 1 11:1.1?. 400 diam.

Tetraspora gelatinosa. ( I'tnt'-h.)

Tliallns vesiculose. ovate-claviit .-, or oli.ivate, gelatinous, \vitli
jige niMMjnally expanded, irregularly t»rn. pallid and <"iii«-timrs
dirty-gr-M-n. Di't.-n incrnsied with lim-- : e.-lls of variable si/..-,
glohnse, either single or geminate, an-1 -catten-d or (jnateriiate.
or geminate, and >"ine\s hat crowded J contents giv«-n and

granular.

SIXK. Cells -003--014 mm. . Rabh.).

llahh. Alg. iii. -In. ll....k. I'.r. Flor. ii. ^1:1. Mackay Flor.
Ilih.T. p.244. Ha^. Alg. p. :;<>1. Kireh. Alg. Schl. p. in'j.
Ulva gtlatinosa, Vaneh. Hi-t. p. I'll, t. 17, f. '2.
Hinilnrin tul^'lima, DC. Fl. Fr ii. p. 5.
In jMMils and ditrhr-.
Plate VI. ji<j. -• a, natural size ; l>. fragment mag. 400 diam.

Tetraspora lubrica. (A'"///.)

Tb alias elongated, tubular, erect, a-i ineli to a j>alm long, 1-4
lines thick, splitting, nndnlat'-, sinu..us, sticky, between gela-
tinous and membranaceoas, yellow-green; crll< globose, or
rather angular, »•!' ni'Mlium size, gn-eii ; tegument very thin.

BIZB. Cells -(MIS-MI! mm ( AW,//.).

Habh. Alg. iii. 11. Kabh. Exs, No. 51. Dickie Bot. Guide,
p. onii. Fng. I'.ot ed. -J, t. -J407. Hass. Alg. p. 3UU, t. 78, f.
10. Kirch/ Alg. Schl. p. !<>'.».

T< trtttpvn l/« litlrica, (iaill. Desm. Ex. i. 655.

r//M liibrt'cu, Koth. Cat. i. 2<>4.

Conr'trm hilirica, lioth. Cat. iii. 1G8.
Plate VL fig. 3. a, natural size; b, fragment mag. 400 diam.

Tetraspora flava. Has,?. A?</. t. 78, /. 11.
Tliallns yellow when dry, cellules small, <|iiaternate.
Rabh. Alg. iii. p. 4±

In rocky rivulets.

PALMELLACEJE. 17

" This species, nt all events, would appear to be distinct, the cells
being two to three times smaller than those of T. lubrica and T. gcla-
t in»sa . ' ' — H assail.

This is a doubtful species, which no one bat Hassall appears to have
seen.

Plate VI. Jig. 4. Fragment magnified, after Hassall.

GENUS 11. BOTRYOCOCCUS. Kutz. (1819.)
Thallns botryoid (or like a hunch of grapes), irregularly
lobed, mucous, involved in a tliin parent ineinltrane (?). Cells
ovoid or elliptic, unite.] in families, which are densely packed
within a thin diffluent tegument.

Represented in Europe by a single species.

Botryococcus Braunii. K>i(z.sp.£§'2.

Small, free swimming, green, at length becoming pallid or
reddish-brown.

SI/K. C.-lls -01--0125 mm. (/?„/,//.).

K'ahh. Alg. iii. 43. Free, in Abb. Senk. t. ii. f. 27-^.
Archer Micr. .Jotmi., 1*7' >, p. 83. Kirch. Alg. fcfchl. p. 111.

In moor pools.

Specimens were found by Dr. M<>ore floating on the surface of Lnuirli
111. -iv in long slieets of some yards in length. .Mr. Areher remarked
ni><>n these " that this was not an uncommon alira in moor pools, some-
times coaling Huluner:_ri d 9, and the like, with a '_'re\ ish green

stratum, sometimes, however, unspended in the water in streaks, and

often i.-olated. It pa-.-i-s through a red condition. More than onee,
\\hena single u'l-oiip of family of this alira, from gat heriirj-s kept f.-r
some time in the lioii-e, had tui'iieil up tinder a low power of tin;
microscope, he had been t< • \:< lit deceived by the way in which it

resembles some nuliolarian rhi/opod, strange as it may seem. The
mucous matrix containing the families..!' e.'lls seems not unfri'qiienily
to give otT rathei long, lilit'orm jirolonira: ions, \\hicli standout more or
less radiantly, looking n«t unlike p.-eiulopodia and these are Undoubted
rhizopoda containing chlorophyll. It mi'-clit, indeed, l>e a t,'ood examplo
of two objects with no atlimty in any respect to each other, still supt r-
ficially simulating one another.1' — Micro. Journ., 1870, p. 88.

Plate I'll. /?//. ~. a, family group ; !>, sin<_rlo family ; c, undergoing
segQieutatiou ; d, free mature cells. All magnified 4uo diameters.

GENTS li>. APIOCYSTIS. A7///. (1849.)

Thallus small, vesicular, fixed by a stem-like base. Cells
globose, scattered, or sometimes 8 disposed in a circle ; contents
homogenous, or delicately granulose, with a distinct colourless
vacuole ; tegument thick, dissolving into a homogenous gela-
tine, cells dividing alternately in all directions. Propagation by
mobile gonidia, which are globose, and furnished with a pair of
vibratile cilia.

This genus consists of a single species, unless the variety linearis of
Niigeli is entitled to rank as specifically distinct.

D

18 COCCOPHYCE^:.

Apiocystis Brauniana. Nag. Einz. Alg. p. 69.

Thallus pear-shaped, pallid green, the cavity filled np by
gelatinous matter, in which are imbedded the gonidia, at first
few, increasing in number with age, as far as 1600.

SIZE. Frond '04--1 mm. high, gonidia '012 mm. diam.,
cells -0075--011 mm. (Rabh.).

Rabli. Alg. iii. 43. Fresen. Beitr. p. 237, t. ii. f. 1-20.
Henfrey in Micro. Journ., 1856, p. 52, t. 4, f. 26-27.

Fresh water ditches, &c.

Professor Henfrey found this plant in January, in a jar of water con-
taining aquatic plants brought from Wimbledon Common six months
previously. The development, as recorded by Nageli, is detailed in the
article quoted above.

"The young 'swarm cells' (zoospores) attach themselves by their
ciliated point (especially to Cladophora fracta), and become invested
with a club-shaped, enveloping membrane. The first division of the
green body then takes place in the direction of the axis of the vesicular
envelope, and is repeated alternately in each direction of space. During
this the vesicle in which the cells (gonidia) lie, continually expands, and
generally becomes very evidently pedunculated. Young vesicles
contain a regular number of cells, namely, 2, 4, 8, 16, 32, &c., but the
number afterwards becomes indefinite ; in largish vesicles, 1-50''
(*5 mm.) long and 1-120" (-22 mm.) diam. I have counted about 300;
in the largest, about 1-25" (*1 mm.) long and 1-50'' (*5 mm.) thick, some
1,600 cells.

" The cells (gonidia) are at first uniformly distributed over the whole
cavity of the vesicle. Subsequently they generally become collected on
the internal surface of the wall of the vesicle, where they lie in one or
more strata. But the cell division always takes place in all directions
of space, the cells situated internally advancing outwards towards the
periphery. In old vesicles the cells are sometimes arranged in rings
of eight upon the wall. When the family of cells is mature for
' swarming,' which may occur at very different sizes and with very
different numbers of gonidia, the cells begin to move, at first slowly,
from their places, and then gradually to circulate more rapidly in and
out about each other ; the vesicle bursts, and the gonidia emerge by the
orifice which is formed. Sometimes the swarming is preceded by the
state in which the cells are arranged in parietal rings.

" The cells secrete an abundant gelatinous coating, which becomes
softened within the vesicle, and confluent into a structureless jelly. The
vesicle sometimes appears merely as the boundary line of the jelly ; in
general, however, it may be distinguished as a distinct wall composed of
denser gelatinous substance, the internal outline of which is always
distinct and sharp, while the outer is frequently indistinct, and partly
dissolved." — Niigeli,

Plate VIL Jiff. 1. a, young frond; b and c, older fronds X 100
diam. ; d, frond with cells undergoing segmentation X 200; e, part of
frond with mature gonidia X 400; f, free gonidia; g, ciliated gonidia or
zoospores X 400 diam.

Inoderma lamellosum, Kutz., has been said to have occurred in
Britain, but we have not been able to satisfy ourselves of its occur-
rence.

PALMELLACE^E. 19

GENUS 13. RHAPHZDIUftl. Kutz. (1845.)
Cells fusiform, or cylindrical, generally very gradually cuspi-
date or acuminate at the ends, rarely obtuse, straight or
variously curved, single, geminate, or fasciculately aggregate,
decussate in the centre, or radiately conjoined, rarely two
laterally united at the end, other cells free. Tegument thin,
smooth. Contents green, very finely granular, furnished with a
central, or rarely lateral, transparent vacuole. Division of the
cells only in one direction.

Rhaphidium aciculare. Braun. Rabh. Exs. 442.

Very slender, 15-20 times as long as broad, yellow-green,
often single, acicular, acutely cuspidate at each end, straight, or
slightly curved or somewhat lunate.

Ankistrodesmus acutissinius, Archer in Micr. Journ., 1862, t.
xii. f. 44-56.

Closterium Griffithii, Berk. Ann. Nat. Hist. xiii. 256, t. 14,

f. 2.

Rhaphidium polymorphum var. y aciculare, Rabh. Alg. iii. 45.

In pools.

" Cells very minute, 20-25 times longer than broad, fusiform, very
slender, straight, very acutely acicular, solitary or forming fasciculi of
2-4 cells ; endochronae light-green, mostly with a minute parietal semi-
circular or rounded pale body or space placed near the middle of the
cell, otherwise usually appearing homogenous, sometimes slightly
granular." It agrees with R. falcatum in its very slender and acute
cells, but it differs from it by its straight, not arcuate cells, by its fusi-
form more quickly attenuated cells, by its more intensely acute extremi-
ties, and by the constituent cells of an old fasciculus being much fewer
in number. — Archer.

Plate VIIL Jig. 3. Cells magnified 400 diam.

Rhaphidium falcatum. (Cor da.)

Fusiform, slender, acutely cuspidate at each extremity,
curved, or semi-lunar, 4-16 congregated in fascicles.

Micrasterias falcata, Corda Aim. Carls. 1835, p. 121, t. 2,

f. 29.

Staurastrum falcatum, Ehr. Weigm. Arch. 1836, p. 185.
Closterium falcatum, Meneg. Linnaaa, 1840, p. 233.
Ankistrodesmus gregarius, Breb. in litt.
Ankistrodesmus falcatas, Ralfs Desm. t. 34, f. 3.
Rhaphidium poly morp hum, var. c. falcatum, Rabh. Alg. iii, 45.

In pools.

It is a very common plant in ponds, &c., and resembles a minute
young Closterium, except that although some individuals may be soli-
tary, others will be seen in the same gathering collected in the charac-
teristic fascicles.

Plate VIIL Jig. 4. a, families magnified 400 ; b, magnified 800 diam.

20 COCCOPHVCE.E.

Rhaphidium duplex. Xutz. Phyc. Germ. p. 144.

Fusiform, slender, slightly sigmoid, single, or 2, 3, or 4
Laterally connected at the poles, otherwise free.

Rhaphidium triplex, Rabh. Krypt. Fl. Sax., p. 134.

Scenedesmus duplex, Ralfs Desrn. 193, t. 34, f. 17.

Rhaphidium polymorphum var. d. sigmoideum, Rabh. Alg. iii.
p. 45.

In pools (apparently rare).

" Cells linear-lanceolate ; extremities tapering to a fine point and
curved in opposite directions. The cells closely united, frequently the
frond, consists of only a single pair of cells so connected, but sometimes
of two or even three of these pairs, which, however, are remote from
each other, in this case ; as the connecting macoua is colourless, they
look like distinct plants, and their relation can be detected only by
moving the frond. If kept in water fo^ a few days, the cells separate
from each other.' — Ralfs.

This description is scarcely accurate, as each cell is a distinct plant.

Plate VIII. fig. 5. a, cells magnified 400 ; b, magnified 800 diam.

GENUS 14. DICTYOSPHJERIU1YI. Nag. (1849.)
Cells elliptic, with thick confluent mucous investment, com-
bined in numbers into free-swimming one-layered hollow-
globular families, one always at the ends of delicate threads
•which proceed from the central point of the family, and which
become repeatedly branched towards the periphery ; division at
the commencement of a series of generations in all directions of
space ; afterwards, as regards the middle point of the aggre-
gate family, as a rule, alternating only in the two tangental
directions.

Only three described apecies, all of which have occurred in the British

Isles.

Dictyospheerium Ehrenbergianum. Nag. Einz. Alg. p. 73.

Families aggregated in a globular, or broadly elliptical
figure ; cells elliptic, very minute, about one-third as broad as
long.

SIZE. Cells -004--0075 mm. (Rabh.}, -004--007 mm. (Kirch.).

Rabh. Alg. iii. 47. Kirch. Alg. Schl. p. 106.

Amongst Confervoe.

" This form is very minute, and in suitable places, common, the
families in the aggregate forming a globular, or broadly elliptic, or
sometimes subcubical figure ; the rate of growth of the delicate thread
being equal all round, the cells at the ends of each of its dichotomous
ramifications stand at nearly equal distance from the original centre ;
hence the regular figure of the aggregate family. The individual cells
are elliptic, and very minute." — Archer.

Plate IX. Jig. 1. Families magnified 400 diam. ; b, fragment with
cells X 400 dium. ; c, variety with spherical cells.

ft

PALMELLACE^E. 21

Dictyosphaerium renif oxme . Buln. Hedwigia n. 22.

Families aggregated in an irregular form ; cells reniform,
nearly twice as broad as long.

SIZE. Cells -008--009 mm. (Rabh), -006--01 X '01--02 mm.
(Kirch.).

Rabh. Alg. iii. 47. Rabh. Exs. 789. Archer in Micro.
Jonrn., 1868, viii. p. 65. Kirch. Alg. Schl. p. 106.

In pools. Near Snowdon, N. Wales.

" This plant possesses larger families than D. Ehrenbergianum, which
are irregularly shaped, seemingly owing to the development of the
delicate supporting fibre not going on in the same regular manner as in
the preceding species, and the cells themselves are much larger and
reniform." — Archer.

Plate IX. fig. 2. a, b, plants magnified 400 diam. ; c, portions show-
ing filament.

Dictyosphaerium constrictum, Archer (M icr. Journ., 1866, p. 128)
having been afterwards found to produce zygospores (see " Micro.
Journ.," 1875, p. 415), has been transferred to the Desmidece
in company with Cosmocladium, to which genus it seems to be
allied.

Cosmocladium Saxonicum, DeBary, is sometimes placed by
authors (as in Rabenhorst's Algas) in this family. But, as
DeBary demonstrated in "Flora" (No. 21,1865), the cells
proceed in the same manner as in Cosmarium, and therefore its
proper place is with the Conjugates^ as one of the Desmidece.
It has been found in North Wales.

GENUS 15. HORMOSPORA. Breb. (1840.)
Thallus tubular, gelatinous, swimming free. Cells oblong,
or oval, green, arranged in simple longitudinal series (families),
either remote from each other, or more or less united at the
poles. Tegument thick, confluent, contained within the broad
gelatinous tube, which is either simple or branched.

* Tubes simple.
Hoxmospora mutabilis. Breb. Mem. FaL 1840.

Tubes intricate, more or less broad, or parallel and coalescing ;
cells twice as long as broad, broadly rounded at each end ;
tegument very thin.

SIZE. Cells •011--017 mm., tube diam. -043 mm. (Rabh.).

Rabh. Alg. iii. 48. Breb. in Ann. des Sci. Nat., 1844, t. i.
f. 2. Kirch. Alg. Schl. p. 108.

In boggy pools. Ireland.

Plate X. ficj. 1. a. portion of filament X 300 : b, same breaking up
X300.

22 COCCOPHYCE.E.

Hoxmospora txansversalis. Breb.

Tubes slimy, equal or undulate ; cells ovate-oblong or fusi-
form, disposed transversely in a nioniliform series ; contents
granular.

SIZE. Diameter of tube -075- -12 mm.

Rabh. Alg. iii. 49.

In bogs.

Plate X. Jig. 3. a, portion of filament X 200 diam. ; b, portion X
400 diam.

** Tubes branched.

Hormospora ramosa. Thwaites.

Tubes broad, gelatinous, irregularly branched ; cells oval or
nearly cylindrical, obtuse at the ends, either remote from each
other or connected, twice as long as broad ; contents green,
with green lamina? radiating from the centre.

Thwaites in Harvey Phy. Britt. t. 213. Rabh. Alg. iii. 49.

In brackish and salt water, attached to Cladophora.

The filaments in this species, unlike those of the preceding two
species, are branched.

Plate X. Jig. 2. a, portion of filament X 200 ; b, small portion with
cells X 400.

GENUS 16. CYLINDROCAPSA. Reinsch. (1867.)

Cells spherical or ellipsoid, membrane thick, either with a
three or fourfold tegument, or naked; cells associated in a
linear series in families, enclosed in a cylindrical hyaline gela-
tinous tube ; cells dividing transversely. Propagation by
gonidia uncertain. Cell contents green, granular, with a single
chlorophyllose corpuscle. — Reinsch Algenflora, p. 66.

Cylindrocapsa involuta. Reinsch Alyenflora> tab. VI. /. 1.

Cells ellipsoid, ultimately involved in a fourfold tegument,
which is expanded at the poles.
SIZE. Cells -023--03 mm. diam.

This plant has occurred in Ireland, as recorded by Mr. W. Archer, in
" Grevillea" (Vol. in. p. 40), with the following observations : —

" Admitting the identity, of which I myself do not doubt, though not
previously having seen examples, that author's description of this
minute alga does not appear quite complete, as he omits to mention that
the cylindrical hyaline envelope of the cells, combining them into a
frond, is closed at both extremities, rounded off at the upper, and some-
what produced, tapered and thin, slightly dilated into a scutate organ of
attachment (to foreign objects) at the lower extremity. Thus the ex-
tremities appear to be differentiated into a basal and apical. The Irish

PALMELLACE.E. 23

plant agreed with Reinsch's in the dimensions of the cells, their oval
figure (truncate after division, whilst closely apposecl, and until full size
is again attained), their longer diameter posed in the direction of the
length of the cylindrical filament and in their being involved by a
number of concentric hyaline investments standing off from the cells at
the poles, closely applied at the sides ; not, however (as Reinsch shows)
uniformly four, but two, three, or four, and standing off from the cells,
not equidistantly, but at different distances. It is, however, quite
possible that where the fewer number only of laminae of the envelopes
were apparent, others may have been present, but so closely applied to
the cells (and to each other) as to appear as if absent. Just as depicted
by Reinsch (though his figure be rather stiff), I saw some of the cells
undergoing self-division, the fission always taking place through the
shorter diameter, the new cells, at first flattened at the ends, then grow-
ing as long as the older, and becoming rounded off, and thus the longi-
tudinal direction of the cells is maintained. Thus this form is unlike
Cylindrocapsa nuda (Reinsch), in which the oval cells are placed trans-
versely, and appear to be without the loose outer envelopes. The
author does not state that the contents are not a bright, but a dull lurid
green, very opaque. On endeavouring to preserve this plant, it ' kept '
not at all, colour became lost, envelope shrivelled, and even after a
couple of days the examples did not represent the same thing as when
fresh.

" Thus the morphology of the plant points to an affinity with Hormo-
spora, Breb., which, too, has its forms with the elliptic cells placed
longitudinally (If. mutabilis and others) and transversely (H. transver-
salis), but no Hormospora, except H ramosa, Thwaites, appears
attached; the contents, too, are bright green, and seem to show a
characteristic internal arrangement not seen in Cylindrocapsa ; the
outer investment is also more mucous. As a form, or a form-species,
(for, doubtless, such as those belonging to Cylindrocapsa and Hormo-
spora can all be accounted no more, so long as no reproductive process
is known) the present plant (Cylindrocapsa involuta} is, per se, abun-
dantly distinct. It appears to be very rare, so does C. nuda,
which I only once met with ; neither is recorded by Rabenhorst in
Tlor. Europ.'

" But whether these Cylindrocapsa-forms be mere stages of other
growths — mere form-species — or permanent parthenogenetic species —
they are entitled to hold a place for purposes of reference until happily
more be, if ever, known as to their development and their right to
rank as independent plants.'' — Grev. III. 40.

Plate IX. f,g. 3. Portions showing spores X 400 diam.

Cylindrocapsa nuda. Reinsch Alg. p. 67, t. 6, /. 2.

Undivided cells ellipsoid, membrane thick, without teguments,
filaments now and then thickened and enclosing four cells.
SIZE. Tube -023--03 mm. diam.

In streams. Ireland.

Cienkowski's* researches on Cylindrocapsa involuta achieved such im-
portant results that they must be indicated here, since the reproduction
will, doubtless, be identical in both species.

" This alga possesses antheridia and oogonia. The oogonium is a
globular inflated joint, it consists of contents and wall; the first presents

* Cienkowski, " Zur Morphologic der Ulotricheen," in Melanges Acad.
Imp. de St. Petersburg, t. ix. p. 531.

24 COCCOPHYCEJ3.

a protoplasmic gonosphere, coloured by chlorophyll, containing numerous
starch granules ; it presents at one point of the periphery very often a
clear spot. The gonosphere is loosely enclosed by the several (3-6) con-
centric gelatinous (as it were swollen or expanded) membranes. Such
oogonia lie either several together, forming a moniliform chain, or they
present themselves in the middle of a series of antheridia, or betweeu
unaltered vegetative joints, upon which, further on, may abut antheridia.
Cylindrocapsa is thus monoicons. At both poles of the oogoninm the
coats are produced into a short cylindrical process ; adjoining processes
are mutually apposed. The size of the oogonia varies ; it may reach
•042 mm., the gonosphere '024 mm.

" The antheridia are discoid or sphseroidal little cells, like the oogonia
possessing a multi-laminated coat, they may form a long series or little
groups of pairs ; they are often enveloped in twos or fours by numerous
laminae. The contents are clear reddish yellow. The male cells (like
the vegetative) are formed by binary division of the mother joint, with
the distinction that they cease to grow, remain smaller, and gradually
assume the yellowish red colour. Each antheridium developes by divi-
sion of its contents two spermatozoids. At maturity they are ejected
with a jerk ; when free, they lie for a while motionless enclosed in their
gelatinous envelope. Presently they assume a tremulous motion, at last
bursting the vesicle and swimming about. They are protoplasmic fusi-
form bodies of about '015 mm. in length, contents sparing, yellowish
red ; at the anterior hyaline point are borne two flagella, below which
are two minute pulsating vacuoles.

" Shortly after their exit they are to be found in the neighbourhood
of the oogonia. The whole cavity of the oogonium becomes pushed out
laterally, dissolving and leaving an opening at the apex of the expansion.
The spermatozoids seem now to be no way aimless in their movements,
their whole object being seemingly to effect a penetration ; with great
energy they drive against the wall, and retreat, and so persist for hours,
until at last the movement ceases, and they shrink into formless little
masses. The actual confluence of the spermatozoid with the gonosphere
was not observed, but the conclusion drawn by the author seems to be
legitimate.

" The next change consists in the appearance of a thick gelatinous
stratum directly on the surface of the gonosphere, which soon hardens
into a doubly contoured membrane. After some days the chlorophyll with
the starch granules gradually disappear, becoming replaced by the
reddish-yellow oily substance. In this way we obtain from the gonosphere
an oospore surrounded by the mucous layers of the oogonium. The
author could never see any further development ; they lasted the whole
autumn and winter without the slightest alteration.

" In some instances the gouospheres on having become enclosed by
the gelatinous envelope began to germinate ; they divided into two
segments, each then becoming clothed by its own gelatinous envelope,
and soon divisions followed just as in the ordinary vegetative joints.
The author supposes that these still green gonospheres could not have
been fertilized, and that only the latter pass over into a state of rest."
— Quart. Journ. AJicr. Sci., 1877, p. 181.

GENUS 17. HYDRURUS. Ag. (1824.)

Thallus adnate, gelatinous, more or less firm, tubular, elon-
gated (2-4-12 inches long), sometimes variously divided, sticky,
surface naked or densely covered with delicate fibres, which at
times are fasciculate. Cells in the beginning globose, or sub-

PALMELLACEJE 25

globose, afterwards elongated, or elliptic, sometimes conoid, one
or other pole colourless, arranged more or less regularly in longi-
tudinal families; tegument thick, at length diffluent, cells
dividing in one direction, chiefly at the apex or periphery of the
thallus. Propagation by means of agile gonidia.

Hy drums penicellatus. Ay. Syst. p. 24.

Thallus rather cartilaginous, olivaceous, of variable thickness,
simple and naked below, divided above, and villous with dense
fibrils. Internal cells elliptical or somewhat lanceolate ; tegu-
ment very thin, scarce visible ; contents homogenous.

Rabh. Alg. iii. 50.

Hydrurus fcetidus, Vauch. Kirch. Alg. Schl. p. 106.

var. e. Ducluzelii. Rabh. Alg. in. 50.

Thallus from an inch to a foot long, oftentimes sparingly
branched, plumose with very dense fibrils.

SIZE. Cells -006--0095 mm. (Rabh.).

Hydrurus Diicluzelii, Ag. Cousp. p. 27. Hass. Alg. t. 77, f.
3. Rabh. Exs. 176, 873, 1193.

Batrachospermum myosurus, Ducluz. Conf. Montp. p. 76.

Palmella myosurus, Lyngb. Hydr. t. 68, E.

Cluzella myosurus, Bory. Diet. iv. 234.

In alpine rivulets, on stones, rocks, &c.

" Root scutate, blackish, hard. Fronds clustered, solid, very gela-
tinous, 2-6 inches long or more, 2-4 lines in diameter, freely waving in
the water, attenuated towards the apex, branched ; branches scattered,
alternate, elongate, slender, beset with other more slender, short raniuii.
Gelatinous mass pellucid, viscid, colourless under the microscope, without
apparent margin, unless as the granules imbedded within its substance
indicate such ; these are globose, green, formed on the stem and primary
branches, most densely set in the ramuli, especially towards the margin.
Colour of the recent frond brownish-olive, or dark brown, in drying
green ; of the granules both recent and dry green." — Lyngbye.

Odour in a recent state very offensive.

One or other of the many forma of this species has been called
Palmodactylon subramosum, Nag., but we have not, as yet, seen any
true British representative of that genus.

Plate X. Jig. 4. #, natural size ; #, portion magnified 400 diam.

GENUS 18. NEPHROCYTIUM. Nag. (1849.)
Cells oblong kidney-shaped, with a dorsal chlorophyllose
vesicle, 2-4-8-16 associated in free swimming families sur-
rounded by an ample oval or kidney-shaped tegument. Pro-
pagation unknown.

Only two European species, both of which have been found in the
British Isles. Both are usually found together, and it is possible that
hereafter they may be referred back to one species, as Nageli pro-
posed.

E

26 COCCOPHYCE.E.

Nephrocytium Agardhiaivum. Nag. Einz. Alg. p. 80.

Cells pale green, almost homogenous, 4-6 times as long
as broad, spirally arranged, in families of 4-8 cells ; tegu-
ment thin which encloses them, length 2-3 times the breadth.

SIZE. Cells diam. -003S--0075 mm. (Rdbli.).

Rabh. Alg. iii. 52. Nag. Einz. Alg. (forma minor'), t. iii.
C. a-h. Kirch. Alg. Schl. p. 112.

In ditches, bogs, &c.

Plate XI. Jig. 1. «, b, families ; c, end view ; d, free cells. All
magnified 400 diam.

Nephrocytium Naegelii. Grun. Rabh. Alg. in. 52.

Cells dark green, granular, twice as long as broad, irre-
gularly disposed, families usually composed of 16 cells ; tegu-
ment thick.

SIZE. Cells diam. -011--022 mm. (Rabh.}.

Nephrocytiwn Agardhiamim, ma/jus Nag. Einz. Alg. t. iii. C.
fig. i, k, p. Kirch. Alg. Schl. p. 113.

In similar or the same places as the foregoing, with which
it is often associated.

Plate XI. Jig. 2. a, b, c, family groups ; d, free cells. All magnified
400 diam.

GENUS 19. OOCYSTZS. Nag. (1855.)

Cells oblong, chlorophyllous, either solitary or binate, qua-
ternate, or octonate ; contained at first within an ample simple
mother cell, at length free by dissolution of the membrane.

This genus, as Mr. Archer has observed (Micr. Journ., 1877, p. 105),
comes very near ~Nep~]irocytiumt the seemingly only very tangible dis-
tinction (it is a very constant one at the least), being the reniform (not
elliptical) cells in the latter genus ; but as forms merely, of more or
less frequent occurrence, those referred to both the genera are indeed
very distinct and constant.

Oocystis gigas. Archer > Quart. Journ. Micr. Sci., 1877, p. 105.

Mother-cell broadly elliptic, almost subglobose, large ; family
usually consisting of two cells.

SIZE. Mother-cell -06--07 X -05--06 mm.

In pools. Ireland.

The broadly elliptical cells are very large, and are really subsphaerical.
" The cell wall," Mr. Archer says, " is by comparison very thick, with
the somewhat nodular little thickening at each pole ; the chlorophyll
granules, in examples in which these were not too dense, could be seen
arranged parietally in a beautifully and curiously regular reticulate
manner, the ' meshes or interspaces of the interior surface of the wall
being bare of them. He had only seen two young cells within theex-
panded mother-cell, four, eight, to sixteen being common in Oocystis
Naegelii. In examples about to produce young individuals, the contents

PALMELLACE.E.

became more dense, and the reticulated arrangements lost, or rather,
perhaps, more properly speaking, the interspaces become clothed with
chlorophyll granules. At first glance this might be mistaken, under a
low power, for that small form of Eremosphtera viridis, which origi-
nates when the individuals of the ordinary large form produce simul-
taneously four, in place of two daughter cells; but the evident elliptic
figure and the thickened poles, as well as the different arrangement of
the chlorophyll contents, would, on closer inspection, at once distinguish
them. Mr. Archer has drawn attention to the seemingly curious very
great expansion of the wall of the mother-cell, almost looking as if in
anticipation, rather than as in consequence of the growth of a young
' brood ' of two, four, eight, or sixteen daughter-cells, so much so that
it almost had the aspect of a fresh growth, rather than that of a mere
swelling up of the old membrane." — Quart. Journ. Micr. Sci., 1877,
p. 105.

Oocystis setigera. Archer, in Quart. Journ. Micr. Sci., 1877, p. 194.

We are unable to give any description of this species which,
as far as we are aware, bears only a manuscript name. Neither
are we able to give figures of either species, although we hope
to do so hereafter.

GENUS 20. DIMORPHOCOCCU8. Br. (1849.)
Cells united in fours on very short branches, dissimilar, the
two intermediate contiguous oblique, obtuse ovate, the two
lateral, opposite and separate from each other, lunate ; families
free swimming, in botryoid clusters.

This genus is allied to Dictyospkasrium, next to which it should have
been placed.

Dimorpho coccus lunatus. Br.Alj. Uni.p. 44.

Green, apices of the cells hyaline.
SIZE. Cells longitudinal diam. '01- '02 mm.
Rabh. Alg. iii. p. 36. Archer, Quart. Journ. Micr. Sci.,
1872, pp. 195, 197.

Floating in pools. N. Wales.

We have been unable to make a successful drawing from the
specimen we possess of this Alga, as we have not seen it living. Mr.
Archer, on reporting upon its occurrence in Ireland, criticised the only
figure extant (in Eabenhorst's Alg. Eur.) in the following terms : " The
upper or outermost cells do not, as they are made to seem, or as the
original description might lead one to infer, stand above the larger and
lower (inner) cells as upon a common stipes, but the former grow off
from the latter, and remain joined thereto by a short pedicle. The inner
eels are broadly reniform, and two stand opposite to each other at the
apex of the supporting stipes, so as to present a lunate figure, and from
the lower part of the sinus made by these it is that the pedicle of each
of the pair of secondary, more or less reniform, but unequally lobed,
cells (one from each lower cell) starts, the smaller lobes of these latter
overlapping each other, and appearing, in a crowded cluster, like one
cell, only of smaller dimensions, concentrically posed above the lower

28 COCCOPHYCE.E.

cell, and as if on a common stipes, that is, as if all were ' in ramulis
— qnaternatim conjunctee.' " The larger lower cells are com-
bined, inter se, by a soft irregular colourless furcated (almost as if
shrivelled) stalk, into a crowded colony or family. This branched cluster
of cells requires to be broken up and pressed out ere the arrangement
referred to can be seen. The structure and mode of arrangement of the
cells (which are bright green, with a pale narrow little space at the
upper extremity, and with large chlorophyll granules) becomes thus of
somewhat complex appearance, nor did it appear to have been made out
fully by Braun himself, as conveyed by his description. — See Quart.
Journ. Micr. Science, 1872, pp. 195, 198.

GENUS 21. MISCHOCOCCUS. Naff. (1849.)

Thallus dichotomously branched, bearing the terminal cells.
Cells globose, terminal, gemmate or quaternate. Division of
cells in one direction. Propagation by zoogonidia.

This genus is confined at present to a single species.

IKEischococcus confezvicola. Nag. Einz. Alg. p. 82.

Cells globose, even, geminate, ternate or quaternate, on the
tips of the branches, bright green, delicately granular, destitute
of a chlorophyllose vesicle ; stem hyaline, spuriously articulated,
often swollen at the angles.

SIZE. Cells -0045--009 mm. (Rabh.).

Rabh. Alg. iii. p. 54, fig. 29.

Attached to filamentous Algse in ditches, near Stafford,
August, 1849 (Rev. R. C. Douglas).

This interesting little plant is liable to be overlooked on account of its
small size and the delicate hyaline stem, only the pair, or more, of little
globose green cells being at first visible.

Plate XL fi(j. 4. a, two plants parasitic on Conferva ; b, young
plants; c, terminal branches with 4 cells ; d, swollen joints of stem; e,
free cells. All magnified 400 diam.

FROTOCOCCACE.E.

29

FAMILY II. PROTOCOCCACE^E.

Unicellular alga?, in the strictest sense, chlorophyllous, with-
out terminal growth, or ramification, without a vegetative
generation of cells. Either single, segregate, or associated in
families. Cells of the families either indefinitely increasing in
number (then forming families} or of a definite number (then
forming a ccenobiiun}.

Propagation by means of gonidia, arising in the mother coll
by free cell formation ; gonidia of two kinds, the one larger,
macrogonidia, the other smaller, microgonidia ; the former
oblong, mostly produced anteriorly into a pale bi-ciliate beak,
rounded and greenish at the posterior end, developing into an
individual plant ; the microgonidia similar to these, and also
motile, but passing after a short time into a quiescent state, and
at last into resting spores, or hypnospores.

This family is usually subdivided into the following sub-
families : —

1. PROTOCOCCE^:. 5. HYDRODICTYE^E.

2. CHLOROCOCCACE^E. 6. OPHIOCYTIE.E.

3. POLYEDRIE.E. 7. PEDIASTRE.E.

4. ScENEDESMEiE. 8. SoRASTRE^E.

9. CHARACIE.E.

Many of these small sub-families include but a single genus, so that,
in effect, the character of the sub-family is that of the genus ; hence
they are of little value, especially in a local flora.

Sub-Family 1. PROTOCOCCEJ:.

Cells sphseroid, segregate ; cytioderm thin, hyaline, without
integument, swimming free, or, when not growing in water,
forming a thin pulverulent stratum. Contents in the beginning
homogenous, then granular, green, or reddish.

Only one genus has yet found a place in this sub -family, of which
one species is British.

GENUS 22. FROTOCOCCUS. Ag. (1824.)
Characters the same as in the sub-family. Propagation by
mobile gonidia.

Fxotococcus vixidis. Ag. Rabli. Alg. in., 56.
Cells small, segregate, accumulated in a broadly expanded
stratum, of a yellowish green colour, either pulverulent, or,
during moist weather and after rain, somewhat gelatinous.
SIZE. Cells -0025--004 mm.

On the trunks of trees, fallen branches, and damp walls
throughout the year.

It is very probable that this is only a condition of Pleurococcus vul-
ga, ris.

Plate XII. Jig. 1. Cells magnified 400 diameters.

30 COCCOPHYCE.E.

Sub-Family 2. CHLOEOCOCCACE^I.

Cells spheroid, either single and free, furnished with a
chlorophyllose vesicle and a pale lateral spot, sometimes with an
ample tegument, or more often accumulated in strata or little
clusters. Propagation by zoospores, formed by division of the
cell contents, escaping by rupture of the cell wall.

GENUS 23. CHLOROCOCCUM. Fries. (1825.)
Cells subglobose, single or in clusters. Characters the same
as the sub-family.

A. Species green.
f Tegument thin.

Chloxococcum humicolum. (Nag.} Rabh. Kr. Fl. Sachs, 137.
Stratum effused, dark-green, pulverulent ; cells globose,
variable in size, often many united in families, involved in a
common hyaline tegument ; cell membrane thin, but thickening
with age ; contents at first pale or yellowish-green, homo-
genous, at length dark-green, granular.
SIZE. Cells -017 mm. diam., or less.
Rabh. Alg. iii. 58.
Cystococcus humicola. Nag. Einz. Alg. 85, t. 3, f. E.

On the naked ground (A. W. Wills}.
Plate X21. fog. 5. Cells and family magnified 400 diameters.

Chloxococcum frustulosum. (Carm.) Eabli. Alg. m., 59.

Thallus effused, pulverulent, green ; cells globose, of medium
size, associated in families which are involved in a broad hyaline
homogenous envelope.

SIZE. Cells -007 mm. diam. ; families to "04 mm. diam.

Hcemato coccus fmstulosus^ Hass. Alg. 380, t. 81, f. 1. Eng.
Fl. v., p. 395. Harv. Man. 181.

PalmeHa frustulosa, Carm. MSS.

On moist rocks.

" It occurs in the form of a greyish black, fragmentary scurf. On the
slightest pressure it separates into corpuscles of various forms, bat
mostly sphoerical, hyaline under the microscope, surrounded by a mem-
branous envelope, and including several granules.'' — Carm.

Plate XII. fig. 2. Families magnified 400 diameters.

Chlorococcum muxoxum. (Grev.} Rabh. Alg. in., 61.

Thallus crustaceous, yellowish-green ; cells subglobose or
oblong, with a rather thick hyaline mucous envelope ; cell con-
tents seruginous-green, homogenous.

SIZE. Cells, including envelope, -016--02 x '01 mm.

Grev. Sc. Crypt. Fl., t. 325.

Hcematococcus murorum, Hass. 323, t. 81, f. 4.

On walls.

PROTOCOCCACEJ^.

We have retained this in its present position in deference to Raben-
horst, to whom the species must have been known. At the same time
its eeruginous green colour seerus to indicate an affinity with Phycochro-
mophycece rather than the present order.

" Plant producing spots on walls and stones of a yellowish green colour,
and at first very small, but afterwards indefinitely larger, from a number
becoming confluent. First discovered in this country by the Eev. M. J.
Berkeley on the freestone walls of Christ College, Cambridge." —
Greville.

Plate ~K.11. fig. 4. Cells magnified 400 diameters. Some undergoing
division.

ft Tegument thick.
Chloxococcum gigas , Grun. in Eabh. Alg., No. 1436.

Stratum thin, green, mucous ; cells globose, large, either
single or associated in small families, always involved in a broad,
distinctly laniellose hyaline tegument.

SIZE. Cells '012--017 mm. diarn. without the hyaline mem-
brane.

Protococcus gigas, Kutz. Phy. Gen. p. 145.

In pools, on walls and glass windows.

One of the finest species in this genus, and possibly not uncommon.
We have met with it two or three times, but not in any great quantity.
It must not be confounded with Glceocystis ampla.

Plate XII. fig. 3. Cells magnified 400 diameters, b, in different stages
of division.

B. Species red, rusty, or orange.
No British species in this section recorded.

Sub-Family 3. POLYEDRIE^E.

Cells single, segregate, free swimming, compressed, 3-4-8
angled ; angles more or less produced, sometimes radially elon-
gated, either entire or bifid, mostly armed, oblong-elliptic when
viewed laterally, rounded or rather truncate at the ends. Cell-
membrane thin, even. Chlorophyll-mass mostly granular,
equally distributed through the cell, sometimes with 1-4 reddish
oil-drops. Propagation unknown.

GENUS 24. POLYEDRIUM. Nag. (1849.)
Characters the same as above for the sub-family.

A. Angles entire.

Polyecbrium gigas. Wittr. Sotvattensalger, p. 33, t. 4, /. 4.
Cells irregularly pentahedrical (rarely hexahedrical), angles
obtuse, sides concave.

SIZE. Maximum diameter of cells '065--075 mm. ; minimum
diameter -035-'045 mm.

Archer, in Quart. Journ. Micr. Science xvii. (1877), p 105.

In standing pools.

This large and distinct species has the angles rounded and unarmed.
Plate XIII. fig. 1. a, b, c, cells in three positions, magnified 400,
after Wittrock.

32 COCCOPHYCF^E.

Folyedrium tetraedsricum. Nag. Einz. Alg.

Cells regularly tetrahedrical ; angles obtuse, mucronate.
SIZE. Cells -015--03 mm. diam.

Eabh. Alg.iii. 62. Archer, Micr. Journ., 1866, p. 62.
In pools.

This might possibly be mistaken for the end view of some species of
Staurastrum, against which error it is essential that beginners should be
cautioned.

Plate X11I. fig. 3. Cells magnified 400 diameters.

B. Angles radiato-elongated.
Folyedrium longispinum. (Perty.) Rabk. Alg. in., 62.

Quadri-radiate, radii thin, elongated, scarcely thickened into
a body in the centre.

SIZE. Length of arms '03--05 mm.

Phycastrum longispinum, Perty Kl. Lebensf. t. xvi., f. 30.

In pools. N. Wales (A. W. Wills).

A peculiar species, which at first sight seems to have but little re-
lationship with the other species figured. It is often found associated
with Desmids, and delights in similar localities.

Plate X11I. fig. 2. a, b, c, d, cells magnified 400 diameters.

C. Angles lobed.
Folyedrium enorme. (Ralfs.) Rabli. Alg. in., 63.

Cells irregularly tetrahedrical, with the angles produced,
hyaline, deeply bilobate ; sometimes repeatedly bilobed, with the
lobes mucronate.

SIZE. Cells '025-'04 mm. diam.

Staurastrum enorme, Ralfs, t. 33, f. 11.

In pools.

" Frond very irregular and variable in form. Sometimes the front
view differs but little from the end one. Usually, however, there is a
slight constriction at the junction of the segments, but I have never ob-
served any difference in the endochrome at that part. The spines, which
are almost confined to the angles, are irregular, some simple and some
branched. The end view has three or four broad and very irregular
lobes ; these are spinous and more or less emarginate, and frequently
one lobe is much broader and more spinous than the others. The spines
on each lobe form two groups, separated by the notch ; they vary much
in size, and are either simple and subulate, or else forked ; sometimes
the forked spines are again divided at the apex." — Ralfs.

A very variable plant, formerly included with the Desmidiea?, but
separated on account of its different mode of propagation.

Plate X1I1. fig. 4. Cells magnified 400 diameters. Lateral and end
views.

Sub-Family 4. SCENEDESME^.

Cells elliptic, oblong, or cylindrical ; cell-membrane very thin ;
cell- contents at first homogeneous, afterwards granular ; chloro-
phyllose vesicle central or siiblateral, and often a lateral colour-
less spot; cells 2-4-16, cither joined in a single series or forming

PROTOCOCCACE^E. 33

a ccenobium. Propagation by division in the cells whence arise
gonidia, which unite themselves into a ccenobium within the
mother-cell, and are at length set free by the rupture of the
cell-membrane.

GENUS 25. SCENEDESMUS. Meyen. (1829.)

Cells polymorphous, equal or unequal at the ends, often pro-
duced into a spine-like horn. Frond or family composed of
from 2 to 8 oblong, fusiform, or elliptic cells, connected into a
single or double continuous row ; propagating by means of the
repeated segmentation, in parallel planes, in one or two direc-
tions, of each of the cell- contents into one or more brood families
(not motile), set free by the bursting of the parent-cell wall. —
Ndgeli.

A. Cells unarmed.
J Scenedesmus obtusus. Meyen. Rabh. Alg. in., 63.

Cells oblong or ovate, obtuse at the poles, 4-6-8 loosely con-
nected in a simple series, or joined obliquely, 3-5 times as long
as broad.

SIZE. Cells -0055--007 mm. diam.

Ralfs Ann. Nat. Hist, xv., p. 404, t. 12, f. 8. Brit. Desm.
p. 193, t. 31, f. 16. Archer in Pritch. Infus. p. 753, t. 1, f.
37-39. Hass. Alg. p. 394, t. 92, f. 15.

In boggy pools.

This species appears to be much less common than 8. quadricauda,
from all forms of which it may be readily distinguished, not only by the
difference in the form of the cells and absence of spines, but the remote.
ness of one cell from its neighbour and their alternation.

Plate XIII. Jig. 5. Cells in families of 4 and 8, magnified 400
diameters.

Scenedesmus acutus. Meyen. Rabh. Alg. in., 63.

Cells fusiform or ovate-fusiform, acute at each extremity,
2-4-6-8 united in a series, either single and straight, or double
and irregularly alternate ; 3-6 times as long as broad.

SIZE. Cells -OOSS-'OOoS mm. diam.

Ralfs Ann. Nat. Hist, xv., p. 404, t. 12, f. 6. Brit. Desm.
193, t. 31, f. 14. Hass. Alg. 393, t. 92, f. 14.

In pools and boggy places.

var. b. obliquus. Rabh. Alg. in., 63.

Cells elliptic, fusiform, arranged in two generally oblique
series, the outer cell of each not in contact with any of those in
the other series.

Scenedesmus obliquus, Ralfs Desm. p. 192, t. 31, f. 15.
English Botany, t. 2933.

Scenedesmus triseriatus, Ralfs Ann. Nat. Hist, xv., p. 403, t.
19 f 7

A.fJj JL i 4 *

34 cocconiYCEJE.

var. c. dimoxphus. Rabh. Alg. ill.. 63.

Cells acute, 4-8, placed evenly in a single row ; inner cells
fusiform, outer externally lunate.

Scenedesmus dimorphus, Ralfs. Ann. Nat. Hist xv., p. 403,
t. 12, f. 5. Brit. Desm. p. 191, t. 31, f. 13. Hass. Alg. 393,
t. 92, f. 13.

Formerly the typical form and its two varieties were regarded as three
separate species, but there scarcely seems sufficient reason for thus re-
taining them. Ralfs wrote of them long ago, " When the cells are nearly
uniform >$. acutus has some resemblance to 8. dimorphus ; but in the
latter the cells are more slender, never ventricose, and are arranged
quite evenly side by side. It is more difficult to distinguish S. acutus
from 8. obliqiius, and I am far from certain that Ehrenberg erred in
uniting them. The principal distinction is that in 8. acutus the cells
form only a single series, which is nevertheless irregular, on account of
the alternate projection of the cells in opposite directions. In S. obUquus,
on the other hand, the cells by division form two distinct rows, which,
after separation, become two fronds." These characteristics are better
shown in Ralfs' figures than in our own, which are more intermediate,
and show an evident approximation to the typical form.

Plate XIII. fig. 6. a, cells of the typical form ; b, cells of the variety
dimorphus; c, of the variety obliquus. All magnified 400 diameters.

Scenedesmus antennatus. Breb. Rolf. Desm. t. 35, /. 27.

Cells fusiform, 2-4-8, joined in a single or double series, all
somewhat curved, usually ventricose, cuspidate at each extremity,
the apices bearing a hyaline globule.

SIZE. Cells •0025--Q035 mm. diam., -013 mm. long.

Rabh. Alg. iii. 63. Archer in Pritch. Infus. p. 753.

In pools.

" Scenedesmus antennatus resembles S. acutus in form, and also in the
arrangements of the cells ; but is distinguished from that and every
other species by having the attenuated points tipped by minute glo-
bules."— Ralfs.

At the time the above was written it had not been found in this
country, and is still the rarest species, if its specific identity can be
maintained.

Plate XIII. fig. 7. Cells magnified 400 diameters.

B. Cells armed.
Scenedesmus quadxicauda. Breb. Ralfs Desm. 190, t. 31, f. 12.

Cells oblong-cylindrical, each extremity obtusely rounded,
2-4-8, narrowly united, either in a single or double series, all
straight, the outer cells at each end (and rarely some of the
intermediate ones) armed at each extremity with a recurved
spine.

SIZE. Cells -0085-*01 mm. diam. to -022 mm. long.

Rabh. Alg. iii. 65.

Scenedesmus quadricaudatus, Ralfs Ann. Nat. Hist, xv., p.
402, t. 12, f. 4. Hass. Alg. 392, t. 92, f. 12. Jenner Fl. Tun.
Wells, p. 200.

In standing water.

PROTOCOCCACE^E. 35

The commonest of British species. A variety has been described
which differs only in being entirely destitute of bristles. We can con-
firm Ralfs in his observation that the species of this genns frequently
make their appearance in clear water that is kept in glasses or bottles
and exposed to the light. He says that he has repeatedly noticed the
appearance of 8. acutus var. obliquus in bottles containing Desmidiece, and
sometimes its rapid increase so as to outnumber its companions. Speci-
mens obtained in this manner, he adds, are frequently more or less
distorted. In little aquaria the present species often becomes a nuisance
from its profusion.

Plate XIII. fig. 8. Cells magnified 400 diameters.

Sub-Family 5. HYDRODICTYE^.

Individual cells oblong-cylindrical, united into a reticu-
lated saccate coenobium, all fertile, some producing macro-
gonidia, which join themselves into a coenobium within the
mother- cell, others producing microgonidia, which are fur-
nished with two vibratile cilia and a lateral red spot ; these
escape from the parent-cell, and, after a brief motile period,
subside into protococcoid, thick-walled spores.

GENUS 26. HYDRODICTYON. Roth. (1800.)

Characters the same as in the sub-family.

" The genus Hydrodictyon comprises, as far as known, but a single
species, which is common to North America and Europe. It grows in
great abundance in the neighbourhood of Philadelphia, especially in the
ditches and stagnant brick ponds in the low grounds below the city,
known as the ' Neck.' There it very frequently forms floating masses
several inches in thickness, and many feet in extent, so that with the aid
of a rake it could be gathered by the bushel. When thus in mass the
colour is very generally dingy and yellowish, although the fronds, when
in active vegetative life, are mostly of a bright, beautiful green. The
plant is in greatest profusion in June and July, after which time it
gradually disappears, until in the autumn it is scarcely to be found, but
early in the spring it reappears. The very young fronds are minute,
oval, cylindrical, filmy. looking closed nets, with the meshes not appre-
ciable to the eye ; when growth takes place the fronds enlarge, until
finally they form beautiful cylindrical nets, two to six inches in length,
with their meshes very distinct, and their ends closed. In the bright
sunlight, they, of course, by virtue of the life functions of their chlorophyl,
liberate oxygen, which, being free to the interior of the net, and its exit
barred by the fine meshes, collects as a bubble in one end of the cylinder,
and buoys it up, so that, the heavier ends sinking, the net is suspended,
as it were, vertically in the water. I know of few things of the kind
more beautiful than a jar of limpid water with masses of these little nets
hanging from the surface like curtains of sheen in the bright sunlight.
A few cells collected in the fall or early spring, if put into a preserving
jar, and the water occasionally changed, will multiply, and in a little while
become a source of frequent pleasure to the watcher.

" As the fronds increase in size they are always in some way or other
broken up, so that, instead of being closed cylinders, they appear as
simple open networks of less or greater extent. The extreme length to
which the frond attains is, I think, very rarely over twelve inches, with
meshes of about a third of an inch in length. The construction of the
frond is always the same. It is composed of cylindrical cells united end

36 COCCOPHYCEJ3.

to end in such a way as to form polygonal and mostly pentagonal
meshes, the size of which varies with the age of the plant. These cells,
which are closely conjoined, but have no passage-ways between them,
are capable of independent life, so that the Hydrodictyon may be looked
upon as an elaborate type of a cell-family, one in which cells are con-
joined in accordance with a definite plan, so as to make a body of definite
shape and size, yet in which each cell is an independent being, drawing
nothing from its neighbours. The cells themselves are cylindrical, with
a thickish cellulose wall, and having no nuclei. Their chlorophyllous
protoplasm is granular, and is placed in the exterior portion of the cell,
forming thus, within the outer wall, a hollow cylinder, in which are im-
bedded starch granules, and whose interior is occupied with watery
contents. The Hydrodictyon cell, when once formed, is capable of growth,
but not of going through the usual process of cell multiplication by
division, so that the adult frond is composed of just as many and, in-
deed, the same cells as it had in its earliest infancy.

"No true sexual reproduction has as yet been discovered in the water-
nets. There have been described, however, two forms or methods in
which the species multiplies, both of them occurring by means of motile
zoosporoid bodies. In the one case these develop immediately into the
new plant, whilst in the other, before doing so, they pass through a
resting stage. Of the life history of the latter, the microgonidia, I
have no personal knowledge.

" The investigation of the production and development of the macro-
gonidia, however, has occupied considerable of the time devoted by
myself to the microscope, and I have seen large numbers of specimens
in almost all the stages of development. I have never been able to
detect any decided motion in the macro gonidia.

11 They are formed in the protoplasmic stratum already alluded to as
occupying the outer portion of the interior of the Hydrodictyon cell.
The first alteration in this, presaging their formation, is a disappearance
of the starch granules, and a loss of the beautiful transparent green
colour. Shortly after this, even before all traces of the starch-grain
are gone, there appear in the protoplasm numerous bright spots placed at
regular intervals ; these are the centres of development, around which
the new bodies are to form. As the process goes on, the chlorophyl
granules draw more and more closely around these points, and at the
same time the mass becomes more and more opaque, dull, and yellowish
brown in colour. This condensation continues until at last the little
masses are resolved into dark hexagonal or polygonal plates, distinctly
separated by light, sharply defined lines. In some the original bright
central spot is still perceptible, but in others it is entirely obscured by
the dark chlorophyl. The separation of these plates now becomes more
and more positive, and they begin to become convex, then lenticular,
and are at last converted into free, oval, or globular bodies. When
these are fully formed they are said to exhibit a peculiar trembling
motion, mutually crowding and pushing one another, compared by A.
Braun to the restless, uneasy movement seen in a dense crowd of
people iu which no one is able to leave his place. Whilst the process
just described has been going on, the outer cellulose wall of the Hydro-
dictyon cell has been undergoing changes, becoming thicker and softer
and more and more capable of solution, and by the time the gonidia
are formed it is enlarged and cracked, so that the room is afforded
them to separate a little distance from one another within the parent-
cell. Now the movements are said to become more active— a trembling
jerking which has been compared to the ebullition of boiling water.
There is, however, with this a very slight change of space, and in a very
short time the gonidia arrange themselves so as to form a little net
within the parent-cell, a miniature in all important particulars of the

rROTOCOCCACE,K. ,37

adult Hydrodictyon. The primary cell wall now becomes more and
more gelatinous, and soon undergoes complete solution, so that the
new frond is set free in its native element.

" It is evident that when the species is multiplied in the way just
described the birth of the new frond is consentaneous with the death
of the old cell. But when the Hyd/rodictyon disappear in the fall, it is
months before they reappear in the spring. It is, therefore, evident
there must be some other method of reproduction. This slow develop-
ment of new fronds takes place, according to Pringsheim, by means
of little motile bodies which he calls Daue?'schwarmer, which has been
translated in English Chronispores (statospores, Hicks). M. Braun stated
already some years since that sometimes, instead of the Hydrodictyon
producing the ordinary reproductive bodies (macrogonidia), there are
formed in the cells much smaller and more active bodies, the micro,
gonidia. The changes which occur in the production of these are very
similar to those already described as happening when the macro-
gonidia are formed. When the chronispores are formed, however, they,
instead of uniting together, escape in a free, distinct condition with
the water. They are now small ovate bodies, with a large anterior
transparent space, to which are attached a pair of cilia, and their life
and history, according to Pringsheim, is as follows : — For a few hours
they move about very actively in the water, and then, dropping their
cilia, and acquiring an outer cellulose wall, pass into a quiescent stage,
in which they closely resemble Protococcus granules. They are capable
of living in this state for a long time if kept in water. They can also
endure dessicatiou if the light be excluded during the process, but if it
be present, they wither and die, and cannot be revivified.

" After a longer or shorter period, but never shorter than three months,
according to Pringsheim, they recommence their life, provided they be
in water. For four or five months after this the chief change consists
simply in an increase in size. The dark green protoplasm is arranged
around the exterior of the cell ; within are the more fluid colourless con-
tents, the whole body still looking like a Protococcus cell. After a size
of about 4*0 th mm. is attained, the endochrome divides successively into
several portions. The external layers of the surrounding wall now give
way in some spot, and allow the inner layers to protrude and form a sort
of hernial sac, into which the several endochrome masses soon pass, at
the same time assuming the well-known characters of true zoospores.
From two to five of these bodies are thus produced out of each original
microgonidium. They are large, ovate, biciliate, and, generally, soon
escaping from the hernial sac, move about actively in the water for a
few minutes. Sometimes, however, they settle down within the genera-
tive utricle. In either case, after a little time, they become motionless,
lose their cilia, and develop into polyhedral cells, which are structurally
remarkable for having their angles prolonged into long, horn-like ap-
pendages. Under favourable circumstances, at the end of a few days,
the bright green endochrome of these undergoes similar changes to
those described as presaging the production of the microgonidia, and is
finally formed into zoospores, which, in from twenty to forty minutes,
unite, within the polyhedron or large cells, into Hydrodictyon, which is
finally set free by a solution of the cellulose coat of the polyhedron. The
network thus formed differs in no essential way from that which arises
in the better known way, except that it is composed of much fewer cells.
It is generally a closed sac ; but when the polyhedron, out of which it is
developed, is small, it is sometimes merely an open network. Its after-
history appears to be identical with that of the ordinary Hydrodictyon
frond."— Dr. H. G. Wood, " American F. Water Alga"

G

38 COCCOPHYCE^E.

Hydxodictyon utriculatum. Roth. Rabk. Alg. 66.

Size of the families (net) variable ; also of the cells (forming
the meshes) and the gonidia, according to circumstances.

Eng. Flora v., p. 359. Harv. Man p. 140. Eng. Bot. (Ed.
2) t. 2504. Hook. Scot ii. 80. Gray. Arrang. i., p. 300. Hass.
Alg. 225, t. 58.

Conferva reticulata, Dillw. Conf. t. 97. Eng. Bot. (Ed. 1)
t. 1687. Huds. An<?. ii. 596. Relhan Cant. 444. Hull Br.
Fl. 331. Abbot Bedf. 275. With. iv. 132. Ray Syn. p. 59.
Dillen. Muse. 20, t. 4, f. 14.

In clear water.

For the development of this species see remarks under the genus, and
also an elaborate account in Braun on Rejuvenescence, pp. 137, 171, 190,
197, 222, and 261. Observations by Cohn " Der Mikroskopischen Algen
und Pilze," p. 109, and Pringsheim " Dauerschwarmer des Wasser-
netzes" (Berlin, 1861).

Plate XIV. fig. 1. a, "Water net," natural size; b, one of the
" meshes " magnified ; c, cell with microgonidia X 300, after Cohn ; d,
portion of cell with angular macrogonidia X 30J, after Cohn; e, free
macrogonidia ; /, active macrogonidia X 600.

Sub-Family 6. OPHIOOYTIEJB.

Cells cylindrical, untequipolar, at first short, then elongated,
either variously curved and contorted, sometimes circinate, one
or other pole attenuated into a thin, short stem, free swimming ;
either straight or more or less curved, collected in an umbel with
a simple stem, or being repeated, forming a composite umbel.
Cell-contents parietal, homogenous or granular, green, sometimes
mixed with scattered reddish or brownish globules. Propaga-
tion by gonidia. — Rabh. Alg. Eur. iii. 66.

GENUS 27. OPHIOCYTIUM. Nag. (1849.)

Cells cylindrical, at first short, then elongated, variously
curved, sometimes circinate, attenuated at one extremity into
a short, thin stem ; free swimming. Propagation by division
of cell-contents and formation of gonidia.

Kabenhorst unites the following genus with the present, giving to it
the characters of the sub-family, but we have preferred to follow A.
Braun and keep them distinct.

Ophiocytium cochleare. Br. Alg. Unic. p. 54.

Slender, pale green, often very long, filiform, variously curved,
circinate, or more or less loosely spirally involved ; stem short,
spine-like, acute or truncate ; contents homogeneous.

SIZE. Cells '005-'0075 mm. diam. ; length variable.

Archer, Micr. Journ. 1866, p. 63. Rabh. Alg. iii. 67.

PROTOCOCCACE2E. 39

Ophiocytium, " Science Gossip," June, 1867, p. 127, fig. 103.
In pools, mixed with other alga?.

Plate XIV. fig. 2. a, young cells ; c, older cells ; b, mature cell X
400.

GENUS 28. SCIADIUM. Braun. (1855.)
Plant from a single individual producing a family. Thallus
(solitary) adnate, unicellular ; cell elongated, cylindrical,
straight, attenuated at the base into a slender stem. Gonidia
about 8, resulting from division of the cell-contents, at length
protruding from the ruptured apex, retained at the mouth and
extending in the form of an umbel, each individual becoming
developed into a cylindrical cell like the mother-cell. This pro-
cess is repeated to a third, or sometimes a fourth generation,
forming a composite or decomposite umbel. Ultimate cells
producing free biciliate zoogonidia.

The cylindrical cell of Sciadium possesses uniformly distributed green
contents, which are interrupted, iu perfectly developed cells, by light
cross streaks, and are divided into a row of 5 to 8 about equal masses,
which become gonidia. I could not detect nuclei in the individual seg-
ments of the contents passing into the formation of gonidia. — Braun
Rejuvenescence, p. 260.

Sciadium arbuscula. Braun Unicell. Alg. p. 106, t. 4.

Umbellate. Cells straight (rarely falcate), obtuse at the apex ;
stem about as long as the diameter of the cells.

SIZE. Cells -0038 mm. (rarely -007 mm.) diam.

Sciadium arbitscula, Micr. Journ., 1866, p. 4. Archer, Micr.
Jonrn. xii., 1872, p. 314.

Opliiocytiwn arbuscula (Br.), Rabh. Alg. Eur. iii. 68,

Attached to confervoid alga3 and aquatic plants.

Braun, writing of this species, says — " It displays an originally obovate
tube, generally becoming elongated into a cylindrical form, obtuse
above, and prolonged into a slender attached pedicel below. The con-
tents consist of uniformly green mucilage, in which a small vesicle
may sometimes be distinguished, but only in the earliest stage of growth.
The pedicel is transparent and colourless, and secretes at its base an
originally yellowish brown, afterwards dark brown mass, which gradually
expands into a disc-shaped foot. When the growth is completed the
green contents become divided into several masses, developing into a
series of 5-8 germ cells ; the cell membrane dehisces, throwing off its
summit as a finger-stall-shaped cover, but the germ cells, instead of
leaving the open tube, all collect at the point of exit with their inferior,
narrower, and somewhat pedicellately elongated ends sticking in the
tube. Thus is produced a capitule, and by the advancing growth of the
young family an umbel formed of individuals exactly resembling the
parent individual from which they originated. The emptied mother-cell
tube remains as the stem and support of the umbellate family, and
gradually becomes filled from above downwards with the same yellow and
reddish brown secreted substance which it exhibits at its own base. The

40

COCCOPHYCE.E.

imperfect birth of the germ cells just described is repeated at the tran-
sition to the third, and mostly even to the fourth generation, so that
little arborescent groups are produced with twice or thrice-repeated um-
bellate ramification, till at length the cells which form the outermost
umbellules scatter out their germ cells, which, after a short swarming,
fix themselves again to be developed into ramified stocks of new
families " -Braun Rejuvenescence, p. 187.

Plate XV. a, b, young cells ; c, commencement of the first generation
of daughter-cells ; d, further progress of the first generation of progeny ;
e, second generation being evolved from the first ; /, old plant evolving a
third generation X 300, after Braun ; g, zoogonidia.

Sub-Family 7. PEDIASTRE^I.

Ccenobium discoid, plane.

For other features of this sub-family see the characters of the genus,
which is the only one at present comprised within it.

GENUS 29. Pediastrum. Meyen. (1829.)
Ccenobium plane, frond-like, discoid, or stellate, free swim-
ming, formed of cells in a single, rarely in the centre in a
double stratum, continuous, or with the cells here and there
interrupted, perforate or clathrate. Cells polygonal, central
entire or slightly ernarginate, those of the periphery entire or
two-lobed, the lobes wedge-shaped, either simple or two-toothed,
sometimes elongated into a horn. Cell-contents green, homo-
geneous at first, then granular. — Rabli. Alg. Eur. iii. 69.

Formerly this genus was included in Desmidiacese, but the knowledge
of its life history has shown that it has no relationship with the Con-
jngatae. Braun illustrated the development of one species (Rejuvene-
scence, PL III.), and we have reproduced some of his figures (on PI. XVI.)
Fig. 1 is an old disc, in great part emptied by the birth of gouidia.
Several of the empty cells exhibit a cross slit, through which the con-
tents have been discharged. The order in which this emptying took
place is indicated by the letters a, b, c, d, e. One cell is in the act of
discharging the gonidia, these having in part entered the projecting por-
tion of the hernia-like vesicle, formed by the swollen innermost layer of
the membrane of the mother-cell, in part still remaining in the internal
cell cavity. Three other cells still possess their perfect contents in
different conditions. Two of them are filled by sixteen extremely closely
crowded gonidia, only half of which are visible, as they form a double
layer. The third unemptied cell is in the actual transition to the forma-
tion of gonidia. It exhibits the first division of the contents into two
halves, one of which already appears halved again. Fig. 2 is anew-born
family immediately after the birth. The innermost layer of the mother-
cell has wholly emerged from the old cell, as an extremely thin vesicle,
enclosing the gonidia, the gonidia in the interior moving actively. Fig.
3 is the same family, as seen from the upper surface. Fig. 4 is the same
family, a quarter of an hour after birth. The gonidia, now at rest, have
arranged themselves in a plane disc. Fig. 5 is the surface of the same
family at the same stage. Fig. 6 the same family one hour after birth.
The emargination of the cells has proceeded further. Fig. 7 the same
again, but four hours after the gonidia ceased to move. The emargination
of the border-cells has passed into the formation of horns. The cells are

PRGTOCOCCACE.E. 41

not even yet closely connected together, but exhibit spaces between
them, so that in this stage it resembles P. pertusum. Not until the
second day do the cells become closely applied together ; the horns ac-
quire their proper shape and length at the same time. All the figures
are magnified 400 diameters,

The number of cells which enter into the composition of a single disc
vary in the same species, so that it cannot be accepted as a character.
The arrangement and limit of species adopted are those proposed by
Brauii (" Algarum unicellarum," 1855).

Plate XVI. figs. 1 to 7. Development of Pediastrum, after Braun; 8
a, b, zoogonidia.

SECTION 3. DIACTINIUM. Braun.
Cells of periphery emarginate or bilobate, lobes entire.

Pediastrum selenaea. Kutz. Rabin. Alg. in. 73.

Coenobium orbicular, entire, formed of 8-16 (rarely 31) cells.
Cells of periphery narrow, lunate, acutely lobed ; cells of disc
slightly excised, central one five-angled ; substance firm, rather
thick.

SIZE.* Coenobium *028-'085 mm. diam.

Braun Unicell. Alg. p. 83. Ralfs Desm.t. 21, f. 5.

Pediastrum Napoleonis, Ralfs Ann. N. Hist. xiv. (1844) t.
12, f. 6.

Pediastrum elegans, Hassall Alg. t. 86, f. 19.

Pediastrum lunar e, Hassall Alg. t. 92, f. 3.

In bogs, moor pools, &c.

Plate XVI. jig. 9. a, 8-celled coenobium ; b, 16-celled ccenobium X
400 diameters ; c, marginal cell.

Pediastrum angulosum. Ehr. Ralh. Alg. in. 73.

Ccenobium orbicular, oblong, or subreniform, continuous,
composed of 8-16-32-64 cells. Cells all even, angular, those
of the periphery truncate at the base and dilated upwards, more
or less deeply notched in the middle, the lobes obliquely trun-
cate, outer angle very shortly apiculate, inner one ending in a
shorthorn. Central cells 5-6 angled, slightly repand in front,
marked with a small transverse oblong pallid spot.

SIZE. Ccenobium '12 mm. diam.; cells '019 diam.

Hass. Alg. t. 86, f. 14. Ralfs Desm. t. 31, f. 11 a b.
Braun Unic. Alg. p. 84.

Pediastrum Boryanum, Ralfs Ann. Nat. Hist. xiv. (1844) t.
12, f. 7, upper.

Pediastrum excavatum, Hassall Alg. t. 92, f. 6.

In bogs.

Plate XVI. fig. 10. a, marginal cells ; 5, 16-celled coenobium ; c, 8-celled
ccenobium X 400 diameters.

* The size must depend on the number of cells of which the ccenobium.
is composed ; hence throughout this genus the dimensions given must only
be accepted as approximate.

42 COCCOPHYCE.E.

Fediastrum Boryanuxn. Turp. Rath. Alg. in. 74.

Coenobium orbicular, oblong, or elliptic, variable in size, con-
tinuous, bright green, composed of 4-8-16-32-64 (rarely 128)
cells. Cells of periphery more or less deeply emarginate, or
two-lobed, lobes horn-like, horns colourless, short or long,
straight, obtuse or nearly so, sometimes a little thickened ;
central cells very closely concrete, 4-6 angled, angular or trun-
cate in front, or slightly repand ; membrane decussately punc-
tate.

SIZE. Cells •02-'G02 mm. transverse cliam.

Braun Unic. Alg. p. 86. Ralfs Ann. Nat. Hist. xiv. (1844)
t. 12, f. 7, lower. Ralfs Desm. t. 31, f. 9 a. Hassall Alg. t.
86, f. 13.

Pediastrum hexactis, Hassall Alg. t. 92, f. 5.

Pediastrum Napoleonis, Ralfs Desm. t. 31, f. 7 a and d (short-
horned form) ; f. b (long-horned form).

Pediastrum simplex B. cruciatum, Ralfs Desm. t. 34, f. 15 d.

Pediastrum granulatum, Braun " Rejuvenescence," pi. 3, 4
(English edition). Pritch. Infus. t. 1, f. 59-69.

In boggy pools.

Plate XVI. fig. 11. a, 4-celled coenobium ; b and e, 16-celled cceno-
bium; c, 32-celled coenobium ; d, 8 -celled ccenobium X 400 diameters.

var. B. granulatum. Kutz.

Cells as in the preceding, but all the cells and the horns dis-
tinctly granulated.

Braun Unicel. Alg. p. 90.

Pediastrum granulatum, Ralfs Desm. t. 31, f. 8.

In the same localities.
Plate XVI. fig. 12. a, b, 8-celled ccenobia X 400 diameters.

Fediastrum bidentulum. Br. Unic. Alg. p. 91.

Ccenobium orbicular or oblong1, continuous, deep green,
sometimes bluish green, nearly blue, composed of 16-32 cells;
cells of periphery two-lobed to the middle, lobes straight, pro-
duced into a truncate, bidentate horn ; central cells 4-5 angled,
slightly repand in front.

Rabh. Alg. iii. 77.

Pediastrum ellipticum, var. (3., Ralfs. Desm. t. 31, f. 10 a, b, c.

In boggy pools.

Distinguished by the marginal cells being divided into two obtuse
lobes, resembling blunt horns, each of which is two-toothed.

Plate XVII. fig. 1. a, part of a 32-celled ccenobium; &, larger 32-
celled coenobium, after Ralfs, X 400 diameters; <?, 16-celled ccenobium ;
d , marginal cell.

Fediastrum constrictum. Hass. t. 86, /. 15, 16.

Coenobium orbicular, or nearly orbicular, bright green, con-
tinuous, smooth (?), composed of 16-32 cells ; cells of the

PROTOCOCCACE^E. 43

periphery irregularly tvvo-lobed, sinus narrow, lobes unequal, now
and then constricted at the base, produced into an obtuse, rather
thick horn ; central cells polygonal, repand in front.

Rabh. Alg. iii. 77.

Pediastrum ellipticum, Ralfs Desm. t. 31, f. 10 d.

Pediastrum Boryanum, ft., Ralfs Ann. Nat. Hist. xiv. (1844)
f. 8.

In standing water.
Braun suspects the verity of this species, which we have never seen.

Plate XVII. fig. 2. a, 32-celled coenobium ; b, 16-celled coenobium X
400 diameters, after Ralfs ; c, marginal cells.

Pediastrum gracile. Br. Unic. Alg. p. 93.

Cells quaternate, closely joined in a circle, centre open,
rarely closed ; cells deeply two-lobed, lobes ovate, produced
into a long divergent, acuminate horn.

Rabh. Alg. iii. 75.

Pediastrum simplex, Ralfs Desm. t. 34, f. 15 a b.

In pools.

This appears to be a very rare species, at first referred to P. simplex
Meyen, from which it differs in the cells, being deeply two-lobed.
Plate XVII. fig. 3. 4-celled crenobia X 400 diameters, after Ralfs.

Pediastrum pertusum. Kutz. Phy. Germ. p. 143.

Ccenobium orbicular, pierced with lacunae, of variable size,
composed of as many as 64 cells ; cells of the periphery loosely
connected at the base, bilobed almost to the middle : lobes
straight, produced into a hyaline horn, sometimes acute, some-
times obtuse or truncate ; central cells more or less exactly
quadrangular, emarginate in front, even, with two paler spots.

SIZE. Perfect cells '016--022 mm. transverse diam.

Rabh. Alg. iii. 75. Ralfs Desm. t. 31? f. 6 a, b. Braun
Unicell. Alg. p. 92.

Pediastrum Napoleonis, Ralfs Desm. t. 31, f. 7 c and e.

Pediastrum selencea, Kutz., Pritch. Inf. t. 1, f. 53.

In pools.

Plate, XVII. fig. 4. a, b, c, 8-celled ccenobia ; d, 32-celled coenobium ;
e, 16-celled coenobium.

var. &. clathratum. Br. Unicell. Alg. p. 93.

Disc pierced with larger openings ; central cells deeply
notched and bilobate.

Pediastrum cribriforme, Hassall Alg. t. 92, f. 4.
Plate XVII. fig. 5. 16-celled coenobium.

var. c. brachylobum. Braun Unicell. Alg. p. 93.

Cells larger, those of the periphery emarginate or trian-
gularly notched, shortly two-lobed ; horns very short, truncate,

44 COCCOPHYCE^E.

or almost obsolete ; cells of the disc perforated 'with smaller
openings.

Pediastrum tricyclum, Hassall Alg. t. 92, f. 1.

Pediastrum Napoleonis, Hassall Alg. t. 92, f. 10. (?)

Plate XVII. fig. 6. a, 5-celled coenobium ; b, 16-celled coenobium, fig.
4 ; /, marginal cell.

SECTION 4. TETEACTINIUM. Braun.

Cells of periphery emarginate or bilobate ; lobes emargi-
nate, bidentate, or bifid.

Pediastrum Ehrenbergii, Br. EabTi. Alg. III., 72.

Ccenobium orbicular or oblong, perfectly closed, composed of
8-16 cells, or quadrate, of 4 cells, which are wedge-shaped,
deeply lobed and arranged in the form of a cross ; cells of the
periphery cuneate, truncate at the base, deeply bilobate; sinus
narrow, lobes obliquely truncate, more or less notched, interior
angles twice as long, all acute, or shortly appendiculate ; central
cells yellow green, polygonal, one side repand or deeply notched.

Pritch. Infus. t. 1, f. 52.

Pediastrum tetras, Ralfs Desm. t. 31, f. 1. Ralfs Ann. Nat.
Hist. xiv. (1844) t. 12, f. 4. Hassall Alg. t. 86, f. 17.

Pediastrum heptactis, Ralfs Ann. Nat. Hist. xiv. (1844) t.
12, f. 5. Ralfs Desm. t. 31, f. 2.

Pediastrum simplex, Hassall Alg. t. 8, f. 17.

Pediastrum biradiatum, Ralfs Desni. t. 31, f. 3, 4.

In pools and boggy places. Not uncommon.

Very variable in size. The 4-celled ccenobia are often to be met
with, mixed with Desmids and other Algae.

Plate XVII. fig. 1. a, four-celled coenobia; &, 8-celled coenobia ; c,
8-celled ccenobium of unusual form, after Ralfs.

var. a. txuncatum. Braun Utticell. Alg. p. 97.

Lobes truncate.

Pediastrum biradiatum, Ralfs Desm. t. 31, f. 4.
Plate XVIII. fig. 1. b, 8-celled caenobia.

var. b. excisum. Braun Unicell. Alg. p. 97.

Lobes slightly notched, emarginate.

Plate XVIII. fig. 1. d, 4-celled coenobium ; e, 8-celled coenobium;
i, Ic, .16-celled coenobia.

var. c. cuspidatum. Braun Unicell. Alg. p. 97.

Lobes deeply notched, evidently bidentate or bicuspidate.
Pediastrum biradiatum, Ralfs Desm. t. 31, f. 3.

In stagnant water, throughout Europe generally.
Plate XVIII. fig. 1. g, h, crenobia; /, marginal cell.

PROTOCOCCACE^:. 45

Pediastrum rotula. (Ehr.) Br. Unwell. Alg. p. 101.

Ccenobium orbicular or oblong, size and number of cells
variable, 4-8-16-32, pierced with openings, bright green, even ;
cells of the periphery truncate at the base, more or less dilated
upwards, deeply bifid, sinus acute, lobes straight, narrow, biden-
tate, teeth erect or divergent, somewhat bent ; cells of the
centre variable in form, usually polygonal, repand, or notched,
containing a single paler spot, sometimes not visible.

Eabh. Alg. iii. p. 79.

Pediastrum heptactis, Hassall Alg. t. 92, f. 9.

Pediastrum incisum, Hassall Alg. t. 92, f. 8.

In pools, &c., throughout Europe.

Plate XVIII. fig. 2. b, marginal cell ; a, 4-celled ccenobiam ; c,
6-celled coenobium ; d, 8-celled coenobinm ; e,f, h, 16-celled coeaobium j
g, irregular ccBnobium.

Sub-Family 8. SORASTEE^.

Cells polygonal, often shortly horned, associated in a hollow,
sphaerical or cubical ccenobium ; cell-membrane thin ; cell-
contents green, homogeneous, then granular ; chlorophyllose
vesicle central or sublateral. Propagation by gonidia, in two
modes in the same species (simultaneous, or after division),
united into a coenobium within the mother-cell, escaping by
rupture of the membrane. — Rabh. Alg. Eur. iii. 79.

GENUS 30. CCE LA STRUM. Nag. (1819.)

Coenobium globose, hollow within, formed of a single stratum
of cells, reticulately pierced. — Rabh. Alg. Eur. iii. 79.

Frond, or family, hollow, globular, or subcubical, composed of poly-
gonal or sphaerical cells, united in one layer into a hollow clafchrate net-
like family, the cells drawn out on the exterior into one or more lobes,
or simply sphasrical ; propagating by the segmentation of the cell-con-
tents into a definite number of portions which become arranged into a
hollow young frond, resembling the parent, ultimately set free by the
bursting of the parent cell. — Pritch. 755.

Ccelastrum sphaericum. Nag. Ein. Alg. 97.

Coenobium globose or subglobose, composed of 4-8-16 or a
larger number of cells, perforated, areolse 3-4-5-6 angled ; cells
rounded, by mutual pressure angular, outer angles somewhat
conical, obtusely rounded at the apex ; interstices 5-6 angled.

SIZE. Coenobium -04-'085 mm. diam. ; cells '021-'023 mm.

Ccelastrum Naegelii, Rabh. Alg. iii. 79. Archer in Pritch.
Infus. p. 755, t. 1, f. 49-55.

In boggy places.

Plate XIX. fig. 2. a, h, families magnified 400 diameters ; c, cell
magnified 800 ; d, cell of C. cubicum, with two obtuse processes ; e, cell
of Ccslastrum, perhaps C. cambricum, with one obtuse process.

H

46 COCCOPHYCE^E.

Ccelastxum cambricuzn. Archer Micro. Journ., 1868, p. 65.

Cells rounded on the exterior margin, each bearing a single
truncate tubercular process.

In pools.

" It was obtained by Mr. Archer on his visit to Wales, and is not re-
ferable to either of the remaining forms (besides C. sph(ericu»i) as
described by Nageli, though perhaps showing most affinity with Ctflas-
trum cuLicu/n, but differing in each cell possessing but one process, or
tubercle-like appendage, not three. These likewise showed various con-
ditions of the growth of the younor coenobia within the mother-cells from,
the earliest stage, tlie most minute of which showed the full character
of the cells, each with the truncate tubercle-like process."-— Quart.
Journ. Micro. Soc., I.e.

Coelastrum microsporum. (Nag.) Braun Alg. Unic. p. 70.

Cells 8-1 6 or 32, exactly spherical, containing a single globule ;
interstices small.

SIZE. Coenobium -04 mm. diam. ; cells '009 mm. diam.
Mtcr. Journ., 1868, p. 65. Pritchard's Infus. f, 755.

In bogs and pools.

" The group (ccenobium) is formed of rather large cells, externally
globularly rounded, their margins, where in mutual contact, being
straight, and leaving at the angles exceedingly minute, somewhat tri-
angular interspaces, like very minute pores, leading into the central
cavity characteristic of the forms appertaining to this genus." — Archer.

GENUS 31. STAUROGENXA. Kutz.

Ccenobium cubical, hollow within, formed of 4-8-16 quad-
rate or sub-quadrate cells. Propagation by quiescent gonidia,
produced after the subdivision of the cell-contents. — Rab.Alg.
Eur. iii. 80.

Crucigenia, Morren in Ann. des Sci. Nat., 1830, t. 20, p.
404.

Staurogenia rectangularis. Brown Alg. Unic. p. 70.

Cells oblong-oval, 4-16-64, associated in tabular families,
almost twice as long as broad, angles obtusely rounded.
SIZE. Cells -0075 x '004 mm.
Archer in Quart. Journ. Micr. Sci., 1875, p. 206.

In pools.
Plate XniL fig. 3. a, families X 400 ; 6, magnified 800.

GENUS 32. SORASTRUM. Kiitz. (1845.)

Ccenobium globose, solid within, free swimming, formed of
4-8-16-32 compressed wedge-shaped cells, which are sinuate,
emarginate, or bifid at the apex, and radiately disposed. Pro-
pagation unknown. — Ralh. Alg. Eur. iii. 81.

PROTOCOCCACE^E. 47

The family (or coenobiutn) in this genus is solid, and not hollow as in
Ccelastrum, composed of wedge-shaped or heart-shaped cells, somewhat
compressed and united into globose families, the narrow ends meeting
in the centre, with the outer margin emarginate or divided.

Sorastruni spinulosum. Nag. Einz. Alg. p. 99.

Ccenobium spinulose, cells wedge-shaped, apex slightly
emarginate, angles obtusely rounded, bi-spinnlose.

SIZE. Ccenobium to '01 mm. diam.

Archer Micr. Journ., 1866, p. 124. Pritcli. Infus. t. 1, f.
56-58. Rabh. Alg. iii, 81. Reinsch Algenflor. p. 86, t. 5, f. 6.

In stagnant water.

Plate XIX. fig. 1. #, &, families magnified 400 diameters ; c, side
view of cell j d, front view of same.

GENUS 33. SEX.ENASTRUM. Reinsch.

Cells semilnnate, joined together by the middle of the convex
margin, in families of 4-8, regularly disposed. Propagation
unknown. — Reinsch Algenflor. Frank. p. 64.

Selenastrum Bibraianum. Reinsch Algenflora p. 64.

Cells semilunate, with the cusps either expanded or curved
inwards ; minor families constituted of four cells in pairs, major
families of these combined in more or less spherical masses.

SIZE. Cells -016--023 mm. long X '005--008 mm. diam.;
minor families '0:23-'031 mm. diam.

In moor pools.

Plate XIX. Jig. 3. a, families magnified 400 diameters; b, pair of
cells magnified 1000 diameters.

Sub-Family 9.

Cells always innate, often distinctly stipitate, variable in
form ; cell-membrane delicate, growing thicker with age (then
double membrane visible) ; cell-contents bright green, homo-
genous, afterwards always granular, with one starch granule,
ultimately divided. Propagation by repeated binary division of
the cytioplasm, resulting in more or less numerous biciliate zoo-
gonidia. — Rabh. Alg. Kur. iii. 81.

GENUS 34. CHARACIUM. Brawn. (1817.)
Cells oblong, ovate, pyriform, fusiform, rarely acicular or
subglobose, equal or oblique, erect or inclined, attenuated at
the base in a hyaline stem. Cell-contents green, homogenous
or granular, zoogonidia, succeeding division of the cytioplasm,
more or less numerous, occupying the whole of the cell, at
length greatly agitated, escaping by a lateral (rarely terminal)
rupture, oblong, with two vibratile cilia. — Braun Unicel. Alg.
p. 29.

48 COCCOPHYCEJ2.

Characium Sieboldi. Br. Alg. Urdc. 32 t. 3,/. A. 1-21 .

Cells erect, equal, at the beginning nearly lanceolate, when
older pyriform or obovate, 2-3-4 times longer than broad, apex
obtuse or broadly rounded ; stem short, hyaline, base attenu-
ated, truncate, not discoid ; contents bright green or yellowish-
green, granular, in the beginning with a single amylaceous
granule, afterwards with several.

SIZE. Cells -022--026 mm. diarn.

Eabh. Alg. iii. 83.

In clear water, attached to filiform algse. Bangor (W.
Joshua) .

" The gonidia of this species exhibit, after they have already attached
themselves by their ciliated extremities, a tremulous motion lasting for
almost a quarter of an hour, and evidently commencing in the delicate
stalk." — Braun p. 230.

Plate XX. Jiff. 9. Cells in various stages, in situ, X 400 ; 10, cells
containing mature zoogonidia ; 11, free zoogonidia.

Characium omithocephalum. Br. Alg. Unic. p. 42, t. 3 C.

Cells from the beginning unequal, incurved, distinctly stipi-
tate, afterwards one side swollen, semilunate, apex produced
into a straight or inclined beak ; stern elongated, slender, base
sometimes discoid ; cell-contents bright green, granular, with a
central or lateral starch granule.

SIZE. Cells -025-'U33 mm. long, without stem, half as wide,
or more.

Micr. Journ., 1867, p. 85. Rabh. Alg. iii. 86.

In pools.

Plate XIX. fig. 5. a, young cells ; d, cell further advanced ; b, c, f,
mature cells in different stages of division ; e, mature cells with en-
dochrome artificially contracted, all magnified 600 diameters.

Characium tenue. Herm. in Rabh. Beitr. p. 26.

Cells erect, narrowly lanceolate, six times as long as broad,
attenuated towards each extremity, somewhat rostrate, and
hyaline above ; stem short, slender, not dilated at the base ;
contents homogenous, bright green.

SIZE. Cells -003--006 mm. diam.

Micr. Journ., 1866, p. 126, 193.

Characium ambiguum, var. c., Rabh. Alg. iii. 87.

Attached to filamentous algaa.
Plate XIX. Jiff. 4. Cells magnified 400 diameters.

GENUS 35. HYDRIANUM. Eabk. (1864.)
Cells as in Characium, but cell-contents at the beginning
homogenous, afterwards contracted into a dark green ovoid
corpuscle, from which, by oblique division, 2-4-8 biciliate zoo-
gonidia are produced, which escape by a terminal aperture. —
Rabh. Alg. Eur. iii. 87.

PROTOCOCCACE.E. 49

Hydrianum heteromorphum. Reinsch contrib. p. 80.

Cells at first globose-elliptical, attenuated below into a thin
hyaline stem ; contents granular, then contracted in prepara-
tion for formation of the gonidia ; zoogonidia elongated, escaping
at the broadly opened apex.

SIZE. Cells, unopened, -008-'0095 mtn. broad ; opened
cells -0066 X '02 mm.

Eeinsch Contributiones ad Algologiam (1874) p. 80, t. 11,
fig. 3.

Attached to filamentous alga?.

Plate XIX. Jig. 6. a, cells in different stages attached to a filamentous
alga magnified 400 diameters ; b, young cells ; c, mature cells magnified
800; d, cell with zoogonidia escaping, and magnified 1200 diameters ; e,
zoogonidia further magnified.

GENUS 36. CODIOLUM. Braun. (1852.)

Cells at first obovate, as they grow older becoming clavate,
or nearly cylindrical, densely aggregated in tufts, base attenuated
into a stem ; cell-contents green, delicately granular, mixed
with numerous starch granules. Propagation by zoogonidia,
and also by resting spores (hypnospores). — Braun Unic. Alg.
p. 19.

Codiolum gregarium. Br. Alg. Unic. p. 20.

Cells elongated, subclavate, green ; many times longer than,
the diameter, apex rounded.
SIZE. Cells -03 mm. diam.
Rabh. Alg. iii. 90.

On maritime rocks (E. M. Holmes]. Also in the drip of
fresh water.

Some persons contend that this is only a marine plant, others that it
occurs also in the neighbourhood of the coast, but either in aestuariea
or entirely removed from saltwater. We include it here without preju-
dice to either opinion.

Plate XX. jig. 1, 2, 3, young plants ; 4, 5, further developed plants ;
6, mature plants X 300 diameters, one containing starch granules, the
other mature zoogonidia ; 7, 8, zoogonidia.

50 COCCOPHYCE.E.

FAMILY III. VOLVOCINBJS.

Ccenobia mobile, globose, subglobose, or quadrangular and
flattened, produced from agile biciliate green cells, with a double
contractile vesicle. Common tegument of the ccenobiuin hya-
line, more or less ample.

Propagation sexual or asexual. The sexual monascoius or
di&cious, either all or some of the cells of the coenobium ex-
hibiting male and female characters. Male cells containing
sperniatozoids (antheridici) , the female finally changed into a
quiet oospore. Non-sexual propagation by means of motile
gonidia (macrogonidia and microgonidia). These arise from the
simultaneous and repeated division of the cell contents (cytio-
jjlastn). Macrogonidia definite in number (2, 4, 8, 16, &c.),
the larger oblong or rounded, with the anterior extremity more
or less rostellate, with two cilia exserted through the membrane
of the vesicle, furnished with a parietal red spot (eye-spot), and
often two contractile vacuoles. Microgonidia indefinite in
number, much smaller, pale or dull green, or yellowish, with
cilia at the apex, mostly even within the mother-cell, endued
with rapid motion, and ultimately escaping by rupture of the
membrane.

Pritchard's " Infusoria " (p. 144) may be consulted with advan-
tage, although including some genera which undoubtedly belong to
Infusoria. Also the various memoirs hereafter referred to under the
several genera.

The passage into amseboid conditions has been observed in several
genera, but this is a subject on which further investigation is needed.
T. C. White has seen it in Chlamydococcus (" Journ. Quekett Micr.
Club," 1679), Archer in Steplianosplicera (" Quart. Journ. Micr. Sci.,"
1865, p. 127), and Dr. Hicks in Volvox ("Quart. Journ. Micr. Sci.,"
1860, p. 99, and 1862, p. 96).

GENUS 37. CHLAMYDOCOCCUS. Br. (1849.)

Cells globose, or subglobose, (4-8 joined in a very fugitive
ccenobiuni), cell-membrane thickish, firm, cell contents granular,
brownish red or vermilion, in certain stages changing into green.
Macrogonidia 2-4-8 rounded, the frontal extremity bearing
very long cilia, and furnished with a central reddish nucleus
and four to six starch granules (not always visible) involved in
a very ample, hyaline, mostly ovoid tegument. Microgonidia
much smaller, numerous, yellowish or dull green, the apex
reddish, biciliate, moving actively within the mother cell, and
at last escaping, by rupture of the membrane.

VOLVOCINE^E. 51

Chlamydococcus pluvialis. Br. Rejuvenescence, p. 206.

Cells subglobose, very variable in size, brownish red, chang-
ing in some conditions to green.

SIZE. Cells -007--035 mm.

Babh. Alg. Eur. .iii, 93. Cohn Nova Acta. xxii. p. 749,
t. 67 A. B. Pritchard Infus. 523, t. xix. f. 20-31. T. C.
White, in " Qnekett Microscopical Journ.," vi. p. 43.

Hcematococcus pluvialis. Flotow, Nova Acta xx.

Hcematococcus Corda. Meneg. Nost. p. 20, t. 1, f. 5.

Hcematococcus mucosus. Morren Rubefact : des Eaux, t. 6,
f. 10-20.

Frotococcus pluvialis. Kutz. Tab. i. f. 1. Cohn, Memoir
on Protococcus.

Protococcus monospermus. Corda, in Sturm Flora ii. 25.

On rocks, stones, &c., in hollows filled with rain water.

" Normally fully developed cells of this multiform creature, sometimes
like a plant, sometimes like an animal, present the ^appearance of glo-
bules from -02 to '04 mm. diam., with a thick, tough cell membrane, and
granular-punctate, opaque contents, sometimes of a brown, sometimes (at
other periods, or in other localities) bright red colour. In the mass of
the dark contents lie hidden several other structures, which at this period
are completely concealed, namely 4-6 starch globules of '0033 or at
most '005 mm. in diameter, in which, as in those of Hydrodictyon, a
nucleus and an envelope may be distinguished, acquiring a violet colour
with iodine, the nucleus becoming rather redder. Sulphuric acid causes
a considerable swelling up of the coat. There also appears to exist in
the centre of the cell a large, very delicate nuclear vesicle, which, how-
ever, is so covered up by the rest of the cell contents, that it can only
be very indistinctly perceived, and cannot even be clearly displayed
when the contents are squeezed out. When these resting globular cells
are placed in water they give birth to four gonidium-like swarming
cells. Even before the commencement of the division of the contents
by which the latter are formed, a change begins in the colour of the
parent cell, the red colour retreating to some extent from the periphery,
and a yellow (sometimes rather greenish) border forming round the deep
red inner mass. The young swarmers also, for a short time after they
issue out, have only a narrow yellow rim round a dark red middle.
During the two or three days' period of movement and growth of these
swarming cells — in which they grow to about four times the original
size, changing their obtusely ovate form at the same time to a reversed
pear-shaped apiculated shape — important new changes take place in the
contents of the cells. The red colour becomes more and more concen-
trated into the middle of the cell, so that a sharply defined bright red
nucleus is formed, in the interior of which a lighter space is often
clearly perceptible, corresponding to the nuclear vesicle above-men-
tioned, around which the red colouring matter forms a covering, mostly
complete, but sometimes imperfect and interrupted. The rest of the
cell contents have become a brilliant green, and in them may be clearly
distinguished the above-mentioned starch granules, as well as many
more smaller green granules. The ciliated point of the cell, often
drawn out like a beak, is colourless. This first moving generation is
succeeded by a not yet accurately determined number of similar active
generations populating the water for some weeks, and often giving it a
bright green colour, till at length universal rest recommences, and the

52 COCCOPHYCE^:.

cells sink to the bottom, or attach themselves to the sides. The transi-
tion from one active generation to another takes place through a transi-
tory resting generation of extremely short duration. The full-grown
swarming cells finally come to rest within their wide shirt-like envelope,
and almost simultaneously divide into two cells, which, without becom-
ing active, divide again into two cells. Thus within the mother enve-
lope are produced four daughter-cells (more properly grand-children),
which begin to move soon after they are completely formed, and, tearing
open the delicate enveloping vesicle, part company. The whole of this
process of development is gone through very rapidly, being completed
in one night and the succeeding morning. The second active generation,
thus formed, resembles the first, with the single distinction that the
active cells are green from the first, and have a smaller red nucleus in
the interior. The subsequent active generations bear a general resem-
blance to the preceding, but many modifications present themselves.
Thus, for example, we not unfrequently see the full-grown swarm-cells
assume strange two-lobed, or even four-lobed, shapes, beginning to
divide before they come to rest ; or sometimes a transverse constriction
and bisection of the cell takes place, caused by a partial protrusion of
it from the loose shirt, &c. The formation of vacuoles is a pretty con-
stant phenomenon in the later active generations, and there may be
several of them eccentrically placed, with the red nucleus retaining its
central position, or a single central vacuole, causing a lateral displace-
ment of the red nucleus. This red nucleus often becomes very small
in the last generations, so that it very much resembles, especially when
rendered parietal by the formation of a central vacnole, the red cor-
puscle occurring in the gonidia of many genera of Algae belonging to
very diverse families, and which was called the ' eye ' in the Volvo-
cinecs by Ehrenberg.

"A total disappearance of the red colour not unfrequently occurs.
In the later stages of the cycle of generations arrives, finally, the for-
mation of microgonidia ; many individuals, instead of producing four
daughter-cells, undergo further division, so as to give birth to a brood
of 16 or 32 minute cells, which, before they separate, form a mulberry-
like body, but separating at length, commence a very active swarming
inside the parent envelope, terminating in the rupture of this coat and
the rapid dispersion of the little ' swarmers.' These are of longer
shape than the large ' swarmers,' only about '0066, rarely '01 mm. long,
of yellowish or dirty yellowish green colour, with reddish ciliated
points. They do not exhibit increase of size, like the large ' swarmers,'
never become coated with a perceptible and loose membrane, and have
no further power of propagation. Most of them die after they have
settled to rest, dissolving away ; others turn into little red globules, and
it is doubtful whether they can grow up to the normal size. If we now
further examine how the cycle of active generations is closed and
carried over to the resting vegetation, we find that the large ' swarmers '
of the last active generation, when their growth is completed and they
have attained the stage of rest, instead of dividing again remain un-
divided, assume a perfectly globular form, and in the course of a few
days become clothed by a thick, closely applied cell membrane, while
the earlier loose distant membrane gradually disappears. The contents,
which at the commencement of the rest were all green, except the little
red nucleus, or even often entirely green, now gradually become red
again, passing from green through many tints of brown, or of brilliant
golden green and golden brown, into red. These globular, thick-coated
cells (the same as those with which we began) behave like seed-cells
or spores, passing into a state of perfect vest. They do not exhibit any
growth, and after the membrane has attained its proper thickness, and

VOLVOCINE.E. 53

the contents their reel colour, no further visible alteration takes place
BO long as they are kept in water. A dessication must take place before
a new cycle of generations can begin. Perfectly dry specimens placed
again in water ordinarily produce active gonidia the next morning.
Original specimens obtained in 1841 had retained their vital force during
a preservation of seven years in a herbarium.

" In order to complete the main features of the picture of the alter-
nating generations of this multiform creature, I must notice that, in
addition to the described active generations (macrogonidia and micro-
gonidia) and the concluding generation, passing into the spore-like con-
dition of rest, there are other generations which, as compared with the
gonidinm-like and spore-like conditions, must be regarded as the proper
representatives of the vegetative development. These are generations
endowed with quiet and slow vegetative growth, which multiply by pure
vegetative division, unaccompanied by any swarming movement. It
depends solely upon external conditions whether the resting cells, which
are here characterized as seed-cells (spores), at once give rise to the new
active generations, or to a series of quietly vegetating generations of
cells. The former is the case when the seed-cells are totally immersed
in water, the latter when they occur on a spot which is at once damp
and exposed to the air, as is the case in the native condition, especially
in the milder intervals of winter, and in the damp season of approaching
spring, but temporarily also at all other seasons, on the margins of the
little basins inhabited by Chlamydococcus, as often as they are filled by
showers of rain. In cultivation in the house these vegetative genera-
tions are rarely observed, while in their native stations they certainly
occupy the most important place in the alternations of the various con-
ditions of life, as may be concluded from the thickness of the crusts
and membranes formed by such vegetative multiplication. The forma-
tion and multiplication of these vegetative generations also take place
by the division of the cell contents, either by simple division, the first
generation being transitory, or by double halving (apparently quarter-
ing). But the newly formed cells do not slip out, like the young
' swarmers,' from the mother envelope ; they remain in the same place
and position. The membrane of the mother-cell appears to become
softened, expands, and becomes gradually drawn out to nothing, rather
than regularly burst open ; it at length vanishes in some undistinguish-
able way, the daughter-cells meanwhile acquiring a tolerably thick,
closely applied cell membrane of their own. The division is repeated
many times in this way, and as the cells all remain in intimate contact,
first small families, but by degrees large conglomerates of cells are pro-
duced. The size of the single cells in these groups varies from '01 to
•02 mm. ; their shape is not truly globular, but partly bounded by flat
surfaces, as results from the alternating divisions, according to the three
directions of space. Ordinarily the colour is light brown. If ignorant
of the rest of its history, one would be led by the form and mode of
division of the cells to regard these crusts as belonging to a Pleuro-
coccus. In the same crusts occur isolated large cells, loosened from
their connection with the others, perfectly globular in form, and appear-
ing to divide no more, but to have passed again into the condition of
resting spore cells. Tney are distinguished from the rest by their
darker contents and thicker cell membrane. Probably the return of
these to renewed resting vegetation takes place by a passage through
the series of active generations. Every shower of rain will wash away
these loose ripe cells of the crusts of Chlamydocnccus ; carried into
collections of rain water, they will soon produce the active brood, which,
returning to rest after a few active generations, settles on the margins
of the little puddles, and then recurs to the resting mode of vegetative
multiplication."

I

54 COCCOFHYCE^E.

The foregoing life-history is somewhat abridged from the account
given by Braun (" Rejuvenescence," pp. 206-214), and for farther de-
tails the reader is referred to the Memoir by Flotow (" Nova Acta
Natura Curiosorum," Vol. xx. p. 11), and that by Cohn (translated in
" Memoirs " by the Eay Society, 1853), which will furnish all that can
be required, and are really exhaustive. For remarks on an Amoeboid
condition see paper by T. Charters White in the " Journal of the
Quekett Microscopical Club " for 1879.

Plate XXL Jiff. I. a, still cells X 400; b, green cell with chloro-
phyll vesicle, and reddish nucleus ; c,, a cell which had been dried six
years, undergoing segmentation after revival ; d, completed division ;
e, division into four ; /, naked green zoospore ; g, encysted zoospore ;
h, primordial cell, commencing division in two ; i, encysted zoospore,
which has deliquesced ; j, primordial cell dividing in four ; k, encysted
zoospore in still condition ; I, division of scill cell into 8 cylindrical
zoospores ; m, escaped zoospore ; n, division of encysted cell into 4 ;
o} division into 8 ; p, division into 32 ; q, zoospores from the latter form
escaped from mother-cell ; r, large red still cell dividing into segments ;
s, red encysted cell ; t, yellow-green still cell. All after Cohu.

Chlamydococcus nivalis. Br. Rejuv.p. 206.

Cells globose, red, at first with a hyaline border, which is the
thickened epispore, which gradually disappears with age.

SIZE. Cells 'Ol-'OS mm. diam.

Rab. Alg. Eur. Hi. 93.

Hcrmatococcus nivalis, Ag. Icon. Alg. t. 31.

Protococcus nivalis, Ag. Supp. p. 13. Hook. Eng. Fl. v.
p. 395. Mackay Hibern. p. 246. Hass. Alg. p. 335, t. 83, f. 2.
Harv. Man. p. 182. Grev. Sc. Crypt. Fl. t. 231.

Palmella nivalis, Hook, in Parry's Voy. App. p. 328.

Tremella nivalis, Brown, in Ross Voy. Supp. p. 44.

Uredo nivalis, Bauer. Journ. Sci. and Art vii. p. 222, t. 6.

On snow and wet rocks, &c.

Probably not specifically distinct from Chlamydococcus pluvialis. For
the history of this minute plant, long known as " Red Snow," consult
" Greville's Scottish Cryptogamic Flora," Vol. iv. plate 231. The inter-
esting observations by Agardh and others, there detailed, are too long
for quotation here.

Introduced to the notice of botanists in this country on the return of
Capt. Ross from Baffin's Bay, where it was found extending for some
miles, it was regarded by Bauer as a fungus, by Robert Brown as an
Alga, and by Baron Wrangel as a Lichen. Agardh first included it in
Algae, under the name of Protococcus nivalis.

It has been found in this country " on the borders of the lakes of
Lismore, spreading abundantly over the decayed reeds, leaves, &c., at
the water's edge, but in greater perfection on the calcareous rocks within
the reach of occasional inundation, more or less perfect at all seasons of
the year." — Carm. Also in Ireland.

Plate XXI. ffj. 2. a, still cells X 400 ; b, cell divided in two ; c, cell
divided in four ; d, advanced stage of subdivision in four ; e, encysted
zoospore ; /, free zoospore ; ff, resting cell.

VOLVOCINE^E. 55

GENUS 38. CHLAftXYDOHEONAS. Elirb. (1833.)

Macrogonidia ovate or oblong-rounded, green, delicately
granulated, involved in a rather narrow hyaline tegument
frontal extremity very obtuse, or somewhat truncate, with a
contractile vacuole, and two cilia ; posterior extremity with a
large chlorophyllose vesicle, and with or without a red lateral
spot. Microgonidia arising from repeated division of the cytio-
plasm of the macrogonidia, oblong or ovate, numerous, pale
green or yellow, becoming brownish. Tranquil oospores glo-
bose, red or brownish, contents firm, colourless, hyaline.

" CMamydomonas is distinguished from Chlamydococcus by the closely
applied membrane (not standing away from the contents) of the old
swarming cells, also by the absence of the little starch-vesicles in the
interior, while, however, as is usual in most of the Palme ilacece, a single
large ' chlorophyll utricle ' (starch utricle ?) exists in the interior.
There is no central red nucleus, as in the gonidia of Chlamydocoecus,
but some species have a parietal red spot. The motion is affected by
two cilia, as in Chlawi do coccus. As in that genus, there is a growth of
the gonidia during ' swarming,' which lasts over the day and night.
There is also a formation of microgonidia. The species of this genus
are doubtless very numerous, but the distinction of them among them-
selves, as well as from the swarming cells of many other Algas, is very
difficult without a complete acquaintance with the history of their lives.
The species Chi. obtitsa, occurs in the Rhine valley, near Freiburg, in
sand pits, which are occasionally almost completely dried up in summer.
The macrogonidia grow during their period of swarming from '016 to
almost '033 mm. long ; they are longish, of equal diameter on both
sides, and very obtuse, almost truncated, having a colourless place at the
ciliated extremity, presenting the form of a notch. In regard to other
points, the contents are dark green, finely granular, with a large vesicle
at the posterior extremity, a roundish lighter space in front of this, and
no red point. They multiply by simple or double halving in several
successive generations. Sometimes a further continuation of the divi-
sion of the full-grown macrogonidia occurs, forming sixteen or thirty-
two macrogonidia from '005 to '008 mm. long, of ovate shape and
lighter colour, tending towards brownish yellow. The resting cells are
globular, about '025 mm. in diameter, at first green, subsequently light
yellowish brown, finally flesh-red ; they have a tough, colourless, and
transparent membrane. Another species, Chi. tingens, occurs in enor-
mous quantity in the puddles of the sandstone quarries at Lorettoberg,
near Freiburg, in the month of March, in mild seasons sometimes even
in January and February. The swarming cells are smaller than in the
preceding, '008 to '016 mm. long, ovate, lighter green, likewise destitute
of a red spot, and the membrane is more distinct in the old age. In-
crease by double, rarely by simple halving, in the former case with de-
cussating sections.

" Several species of this genus, previously included in the animal
kingdom, but nearly allied to Gl&ococcus and Chlamydococcus, present
themselves in the beginning of spring, in such abundance that they
produce a striking green colouration of the water ; a few weeks later
they vanish, leaving no trace, and are not noticed again throughout the
whole vear." — Braun Rejuvenescence, p. 215.

56 COCCOPHYCE.E.

Chlamydomonas pulvisculus. Ehr. Infus. p. 64.

Macrogonidia ovate, twice as long as broad, or nearly ; deep
green, with a bright red lateral spot.

SIZE. Diam."oo65--01o mm.

Rabh. Alg. £Sur. iii. 94. Colin in Nova Acta. xxiv. t. 18, f.
28. Fresenius Beitr. 235, t. 11, f. 43-45. Pritchard Infus.
521, t. 18, f. 40, 51-54.

Diselmis viridis, Dujard. Zoophy. 342 iii. f. 20, 21.

In stagnant water.

" These creatures form a large portion of the green matter which
colours the water contained in water-butts, ponds, and puddles in the
summer and autumn, especially after a storm. Whenever these exist in
large quantities, multitudes of them, and of their envelopes, rise to the
surface of the water, and form a green stratum upon it." — Pritchard.

Plate XXI. fig. 3. a, swartnspore ; &, c, encysted and undergoing
division ; d to g, gloeocystis forms ; /*, resting cells, after Cieukowski X
400 ; i, stellate cyst, from Stein ; j, individual differentiated ; k, swarm-
ing X 600.

GENUS 39. VOLVOX. Linn. (1758.)

Coenobium sphaerical, continually rotating and moving, look-
ing like a hollow globe, composed of very numerous cells
arranged on the periphery at regular distances, connected by
the matrical gelatin ; furnished with a red lateral spot, two
contractile vacuoles, and two long exserted cilia, all circum-
scribed within a common hyaline vesicle. Propagation sexual
or non-sexual. In the non- sexual certain distant cells greatly
enlarge, divide into numerous parts, and evolve daughter-
ccenobia within the parent-ccenobia, which are ultimately set
free. In sexual propagation certain masculine cells undergo a
multipartite division into fascicles of mobile spermatozoids
which are contractile, pear-shaped, and biciliate, afterwards
free. The female cells are enlarged, but do not undergo
division ; after fertilization they develop into motionless
oospores, which are finally red, surrounded by a double epi-
spore.

The following is a summary of the structure and life-history, of
Volvox as given by A. W. Wills in the "Midland Naturalist"
(Sept.-Oct., 1880) :—

" It seems hardly necessary to describe the normal aspect of this
organism. Briefly, under a low power, it is seen to consist of a sphserical
globe of mathematical perfectness, so transparent that, as it glides
along, any object over which it passes is clearly visible through its
vacant spaces, i.e., through such parts as are not occupied by the struc-
tures presently to be noticed, while by focussing the binocular on the

VOLVOCINE^E. 57

lower half of the plant the effect is obtained of looking into the inside
of a glass sphere of crystalline purity and of absolute symmetry. The
diameter of a full-grown Volvox is usually about 1-60", and individuals
are to be foucd in each colony varying from this down to about 1-80".
The inner surface of the sphere is studded at intervals with dark green
points, not disposed irregularly, but so arranged that each is usually the
centre of a group of six others, placed at the extremity of nearly equal
radii. These green points are ' gotiidia,' each probably endowed with
the potentiality of becoming a perfect Volvox, though only a certain
number of them actually undergo that sequence of changes which
results in their becoming fresh individuals resembling the parent
sphere.

" Each gonidium is either sphasrical or pyriform (in which case its
pointed end is directed outwards), and contains, in its early stages at
any rate, one or more contractile vacuoles disposed among a mass of
granular endochrome, and stated by Busk to pulsate rhythmically once
in about forty seconds. (Plate 23, Fig. 6.)

" At this period are also to be seen in the body of the gonidium one,
two, or three — occasionally even more — brilliant colourless spots, from
one of which is probably derived a nucleus which can be detected by the
use of reagents at a later period.

" There is also often lodged within the substance of the zoospore a
brown or red ' eye-spot,' and all the eye-spots in an individual look, so to
speak, one way.

" The apex of each gonidium is more or less produced into a trans-
parent point, from which proceed two cilia several times as long as the
gonidinm itself, which pass through two minute pores in the outer cell
wall, and move freely in the surrounding water. I am fortunate in
having mounted a specimen of Volvox, in which these pairs of foramina
are clearly shown, and the regularity of their disposition at a uniform
angle to the equator of the sphere is striking. (Plate 23, Fig. 7.) It is,
of course, by the combined action of these numerous pairs of cilia that
the whole organism progresses. Of the direction of the resultant
motion we shall speak shortly.

" Viewing the surface of the sphere with its convexity presented to
the objective, we find, by very careful adjustment of light, that from
each gonidium there runs to each of the six surrounding ones a fine
thread, sometimes double, occasionally triple, always of extreme tenuity
(Plate 22, Figs. 1 and 3), of such tenuity, indeed, as to be frequently
invisible ; but as the use of certain reagents often brings these lines
into view where it had been previously impossible to detect them, and
as they may be sometimes discerned for an instant when the eye is
applied fresh and unfatigued to the microscope where even a moment
later they seem to be absent, it may be assumed that the structure is
universal, though often far too subtle to be detected. It is needless to
say that no skill of the draughtsman can even suggest its infinite deli-
cacy, while tbe figures given in books, not excepting the beautiful
drawings in Ehrenberg's ' Infusionsthierchen,' exaggerate the strength
of the connecting lines to tbe extent of grossly caricaturing the extreme
fineness of Nature's own handiwork.

" To return to the gonidia and their history. A certain number of
these in each individual are selected to produce a group of young Vol-
voces within the parent sphere. The books fix this number as usually
four or eight ; but out of twenty-five individuals now in the field of my
microscope I find only three containing four incipient spheres of tbe
second generation, while only one contains eight, and there are four
containing five, six with six, ten with seven, and one with nine such
progeny. Almost every Volvox, when first discharged from the parent

58 COCCOI'HYCE^E.

sac, and possessing a diameter of about 1-170", already contains a
certain number of enlarged gonidia, destined in due time to become its
own progeny. Not only so, but long before its discharge, and while yet
it exists as a daughter-cell within the protecting cavity of the parent
generation, these selected gonidia are already visible as spots larger and
darker than their fellows. (Plate '22, Fig. l'.)

" The history of these selected gonidia, as it may be traced in a
daughter-sphere recently cast foith to seek its fortunes in the world of
waters around it, is as follows : — The enlarged gonidium is at first a flat,
thin circular disc, appressed to the internal surface of the sphere, and
being surrounded by eight of the ordinary zoospores, is derived from
the coalescence of the two central ones out of a group of ten. (Plate
23, Figs. 1, la.) Shortly, this disc assumes a more distinctly oval form,
with a slight constriction across its lesser diameter, in which stage it
often much resembles a young Cosmarium. (Plate 23, Figs. '2, 2a.) It
is soon seen to be clearly subdivided into four, and its thickness having
grown pari passu with its superficies, the group now protrudes into the
internal cavity of the parent-plant. (Plate 23, Figs. 3, 3a.) Repeated
subdivision now goes on rapidly (Plate 23, Figs. 4. 4«), till the whole
body assumes a sphserical form, a distinct cell wall being at the same
time formed, which is revealed by careful illumination, and still more
clearly by the use of reagents, as a hyaline sphere concentric to and of
larger diameter than the green one within it, so that there appears to be
a clear space or ring between the two when seen in section. (Plate 22,
Fig. 5, 5a.) Finally, the young Volvox consists of a vast number of
deep green granules closely packed together, and by mutual pressure
driven to assnme a more or less distinctly hexagonal form, and corres-
ponding in number to the gouidia which are to stud its surface when its
growth is completed. Shortly hei'eafter, the whole organism continuing
to increase in size, clear spaces appear between the gonidia, showing
that the enlargement of the cell wall and its interspaces is outstripping
tli at of the gonidia, which are now approaching maturity. The inter-
lacing connecting threads are developed simultaneously. (Plate 22, Fig.
la.) During the whole process the centre of the young Yolvox spheres
continually recedes from the periphery of the parent, so that when the
group of young ones has attained the full development of which it is
capable in this stage they are often pretty cl sely packed in the internal
space, and sometimes even slightly deformed by mutual pressure, each
by this time closely resembling the parent in miniature, and already
containing enlarged gonidia of the third generation. (Plate 22, Fig. 1.)
By this time the clear space originally visible between the gonidia and
the cell wall has been obliterated, and the cilia may be seen protruding
through the latter. Some writers state that the daughter-cells rotate
at this period within the parent cavity. I have frequently seen them
oscillate so far in one direction and then back to their original position,
but have never observed a true rotatory motion. Finally, the young
Volvoces are liberated by the rupture of the parent sac, at a special
point, clearly marked out for this purpose in its structure. I have not
met with any observations on this point, but have fully convinced
myself that it may always be predicted at what point this rupture will
be effected.

" The combined action of the pairs of cilia in which the gonidia
terminate is the actuating power whence proceed both the rotatory and
the progressive movement of Volvox, and these are both in a definite
direction. If an imaginary axis be drawn through the sphere, the pro-
gressive motion being, so to speak, from the north to the south pole of
that axis, the rotatory motion is usually from west to east, though not
always, being occasionally reversed for a few seconds ; but for the

VOLVOCINE^E. 59

greater part of the time it is regularly in the direction indicated, and
the point of rupture of the sphere ivill be at its north pole.

" It is difficult to determine precisely how this rapture is accomplished,
but I believe it to be by a special contraction of the walls of the parent,
or of the invisible primordial utricle, not by the outward pressure of
the daughter spheres, this force being evidently inadequate to produce
the result where their number is small, whatever it may be when it
reaches its maximum.

" Shortly before the emission of the young the cell commonly assumes a
slightly pyriform. shape, and then slowly opens at its apex, but the aperture
is of less diameter than that of the young Volvoces, and as each of these
passes out, the month of the bag is visibly stretched, and resumes its
original size after each daughter sphere has escaped, so that it evidently
possesses considerable elasticity, a property also made manifest by the
fact that the normal form of Volvox may be considerably flattened by
the pressure of a glass cover, and yet resuoie both its sphaerical form and
its motion when this pressure is removed.

" Moreover, the daughter sphere passes out ivithout rotating, and from
whatever cause it derives its impulse, this often suffices to drive the
young Volvox clear of the mouth of the sac to a distance equal to
several times its own diameter, in which position it pauses motionless
for some seconds, and then, commencing to rotate gently, sails away, at
first slowly, then more and more rapidly, to enjoy its independent
existence.

"After the rupture of the sac, the gonidia near the edges of the
opening are seen to quiver, from the action of the cilia, where they are
partially freed from the support of the surrounding envelope, and the
same thing occurs when they are forcibly torn from their attachment,
in which case they may even move for awhile freely through the
water.

"The general action of the cilia continues for some time, and the
empty sphere rotates as before, its general direction being still from
north to south, with the open end to the rear. After a time, which I
cannot specify, the cilia cease to play, and the organism decays, having
fulfilled its destiny in life.

" The birth of the young Volvocesis affected by various circumstances.
Doubtless the process is, under natural conditions, most active in the
early hours about dawn, when the analogous functions of similar
organisms are well known to be most energetic, but in order to see the
phenomenon in full vigour it is only necessary to place a number of
mature parent- spheres, such as are found in every colony, in a shallow
live-trough, and to bring them into a warm room. In an hour's time
almost all the young plants will have been liberated. Light and heat
stimulate the action, while cold and darkness retard it. The ciliary
action is aff acted in a remarkable degree by altered external conditions.
It' a drop of water considerably colder than that in which the Volvoces
are floating be allowed to flow in under the cover-glass, the whole are
paralysed for some seconds, after which they slowly resume their motion.
A sudden mechanical shock produces a similar effect. A sufficient
degree of heat to make the water distinctly tepid to the feel causes
instant and simultaneous death of the whole colony.

" During the day the majority of the Volvoces contained in a shallow
vessel rise to the surface, although they avoid strong direct sunshine,
while at night they retire in a cloud to the bottom.

" The astonishing number in which the spheres at times appear in
some pool, and their equally sudden disappearance, have been frequently
remarked. Doubtless a very slight change in external conditions suffices
on the one hand to favour the development of countless thousands of

60 COCCOPHYCE.E.

young plants, and on the other, either to destroy the vitality of the
whole colony or to drive it to seek ref age in deeper water.

" A curious instance of this sensitiveness to varying conditions of light
and heat occurred to myself. I had two shallow vessels in a north
window, each containing a goodly supply of Volvox. Cold and inclement
weather, which prevailed for weeks together, seemed to check their
increase, for I found but few young spheres from day to day among the
older ones. Thinking that a moderate degree of warmth would tend
to increase my colony, I transferred one vessel, fortunately not both, to
the floor of a warm greenhouse. In forty-eight hours all were dead, and
in a few days scarcely a vestige remained of the countless corpses which
had copiously strewed the bottom of the glass.

" We must now revert to the minute structure of the mature parent-
sphere, which has been exhaustively studied by Cohn, Busk, and
Williamson.

" In the outset it should be stated that the last-named observer
believes that there are two distinct forms of Volvox, in one of which
the peculiar structure which I am about to describe exists, while it is
absent from the other. Busk disputed the accuracy of Williamson's
observations on this point, but in an appendix published subsequent to
the body of his essay he states that he has detected this same structure
in specimens from Manchester, but not in his own.

" I have failed to develop it by the means recommended by William-
son, but have succeeded in making it evident enough in a great number
of specimens from. Sntton, by the use of these reagents, and especially
by the application of aniline purple, an invaluable auxiliary in the
examination of minute vegetable cell-structures.

" This substance stains the protoplasmic elements of such structures
to a colour which appears deep purple by direct light and crimson by
dark background illumination, and reveals details which are wholly
invisible without its use.

" The colour is, however, greedily absorbed by some of the materials
used by the microscopist, so that a judicious choice of these is necessary
to ensure success. Objects stained in this manner are, for instance,
rapidly bleached if mounted in gold -size cells, and I have for the present
adopted zinc-white in its place. Among other reagents which I have
used are eosin, iodine, iodised glycerine, carmine solution, potassium
permanganate, nitrate of silver, and other salts, some of which bring
into view various parts of the minute structure of plants ; but aniline
colours, applied with due precautions, produce the most rapid and
striking effect.

" Professor Williamson describes the structure in question as a net-
work of lines dividing the whole surface into hexagons, in the centre of
each of which is seated one of the gonidia.

" The delicate ' protoplasm-threads ' proceeding from each of these
to its six surrounding neighbours never pass through the angles of the
hexagons, but always through the side of each hexagon to the next
gonidium. (Plate 23, Fig. 3.) Hence it appears that 'the points of
a«lhesion are chosen prior to the development of the outer cell
membrane,' in which light Williamson regards the hexagonal division.
In his specimens this structure was developed by immersion in glycerine
for some time. I have failed to obtain more than the faintest sugges-
tion of it by these means, but it is often brought out by the application
of aniline purple, as is also an important detail shown in drawings
made from his preparations, viz., that at the angles of the contiguous
hexagons there is sometimes a distinct doubling or separation of the
lines, whence he concludes that each side of the figure is really formed
by two delicate cell-walls in close juxtaposition, the duality of which is

VOLVOCINE^E. Cl

only made evident by the action of reagents. (Plate 22, Fig. 2.) He
regards the globe of Volvox as a ' hollow vesicle, the walls of which
consist of numerous angular cells filled with green euclochrome, &c., the
intercellular spaces being more or less transparent,' and the ciliated
zoospore as representing the endochrome of a cell having two walls, the
internal one being separated from the outer cell-wall, except at a few
points where it is retained in contact by the connecting filaments, and
the external one forming the hexagonal divisions on the surface. He
further holds that the periphery of the sphere, when seen in section,
has an appreciable thickness, its inner margin being definite and parallel
to the outer one ; and that the sides of the hexagons being continued
downwards through the thickness of the outer membrane, the appear-
ance of all these structures, if they could be seen simultaneously, would
be that shown in Plate 23, Fig. 6.

" Even in deeply stained specimens I have never been able to detect
the existence of these hexagons as other than an entirely superficial
structure, and at present my impression is that the hexagonal structure
has a different significance.

" In the very early stage of Volvox-life the embryo gonidia are
encased in a distinct transparent outer-sphere. (Plate 23, Fig. 5, 5a.) At
a later period owing to the more rapid growth of the gonidia than of
the case, the latter closely invests the former, which are, in fact,
embedded in it. In the next stage, if not in the earlier condition, by
the continued growth of the gonidia at a greater rate than that of the
containing sphere, they are so closely appressed as to assume the hex-
agonal form, and the interstices must of necessity consist of a thin film
of the substance of the containing sphserical envelope, moulded, so to
speak, into corresponding forms. But now the diameter of the young
Volvox, which is by this time sent forth on its independent career,
rapidly increases, the gonidia assuming their sphserical or pyriform
shape as their mutual pressure diminishes, and being hourly separated
by greater intervals. If, now, the actual formative matter of the sphere
receives no further or only a disproportionate increment, but is
gradually attenuated by continued expansion, as a soap bubble is dis-
tended by blowing into it, the hexagonal lines into which it has been
moulded by the previous mutual pressure of the embryo gonidia will be
gradually stretched in all directions into finer proportions; and just as
this figure is that which is necessarily assumed by a number of sphaerical
bodies under mutual pressure, so the most economical disposition of this
particular part of the Volvox-structure will necessitate its constant
attenuation into hexagons of ever-increasing delicacy. (Plate 22, Figs.
1,3; Plate 23, Fig. 7.) If the process be continued long enough, it
may finally result in the structure becoming too filmy to be detected by
any microscopical observation ; and it is worth noticing that it is
usually in spheres of small or medium diameter that the hexagonal
divisions can be developed, and not in those of the largest size. Such
appears to me at present to be the rationale of the formation of this
structure.

" The internal cavity of the sphere is said to be filled with a * muci-
laginous fluid.' L If a Volvox be ruptured under a cover-glass, and aniline
purple introduced by capillary attraction, the colour seems to be for a
while repelled at that part which is in front of the rupture, and to flow
round it on either side. It is only after a considerable time that it
gradually penetrates this space, and brings out, by staining it of a deep
purple tint, a mass of hazy matter, from which proceed streaks or
lines radiating more or less regularly from its south pole. This structure,
to which I do not think attention has been hitherto called, is also some-
times developed in deeply stained specimens within the slightly

K

62 COCCOPHYCE.E.

ruptured sphere, and seems to show that there is a denser layer of
thick matter, whatever its nature may be, disposed in a somewhat
regular manner, being concentrated near the south pole of the axis of
rotation, whence it spreads over the inner surface in streaks resembling
the lines of longitude on a terrestrial globe.

" Both from its position and from the rapidity with which it is stained
by aniline purple, without which its existence is apparently absolutely
undemonstrable — (in which respect it is in marked contrast to the outer
cell-wall, which latter is only faintly tinted by somewhat prolonged
application of the reagent, and then only where the hexagonal structure
exists) — I have no doubt that this inner layer is the true ' primordia
utricle ' of the cell, and possesses that character of vital and formative
matter which distinguishes this element of cell-structure from the outer
wall, which, on the other hand, probably consists of cellulose or some
similar compound. Probably the arrangement of this inner layer, in
radiating lines or ribs, contributes to the elasticity of the fabric, whereby
it is enabled to open at a given point for the escape of the young, and
to contract again after their emission.

" The increase of individuals by the means already described is
strictly an instance of subdivision.

" But Volvox globator also affords an instance of true alternation of
generations. As may probably be affirmed of all living organisms, its
life-history would be incomplete without a process of sexual reproduc-
tion, and accordingly, after a long sequence of asexual generations, a
strictly sexual process intervenes, from which result certain spores
destined to lie dormant for a while, and, like the zygospores of the
Conjugate Algae, to resist vicissitudes of condition and climate
through the rigours of winter, and then to produce the parent form in
the succeeding year, when external conditions again favour its develop-
ment.

" Cohn fully traced the various stages of this process, and desci'ibed
them in the ' Beitrage zur Biologie der Pflanzen ' (1875, Vol. I., Heft. 3),
and in the ' Annales des Sciences Naturelles ' (4 ieme Ser. Bot., Tom.
V., 323) ; and his observations have been more or less confirmed by
other investigators, especially by Carter (Ann. Nat. Hist., 3rd Ser., Vol.
III., 1859, p. 1), and more recently, in 1877, by a French botanist, M.
F. Henneguay.

" Cohn and Carter both hold that there are two varieties of Volvox,*
one monoecious, the other dioecious, and the latter maintains that
Sphcerosira Volvox is the male form of the dioecious sub-species. Be
that as it may, the reproductive process in the monoecious form is as
follows : — The sexual reproductive cells, male and female, occur in
spheres of unusual size in the autumn, and are few in proportion to the
number of sterile cells, and the reproductive process does not occur
simultaneously with, but as a climax to a long series of asexual genera-
tions. On their first appearance the gynogonidia or female cells are
about three times the size of the sterile ones, of a deep green colour,
and of a frothy consistency from abundance of vacuoles. They are
easily distinguished from the parthenogonidia by their never sub-
dividing. (Plate 22, Fig. 5b.) They next become flask-shaped, their
narrow end touching the periphery of the sphere, and the broader end
hanging free in the internal cavity. (Plate 22, Fig. 5#2.) Finally, they
assume a sphaerical form, and become oospheres, each enveloped in a
gelatinous membrane. (Plate 22, Fig. 5b3, &4.)

" The androgonidia. or male cells, at first closely resemble the par-
thenogonidia, but undergoing division in two instead of three directions,

* The two forms are here accepted, after Stein, as Volvox globator and Volvos
minor.

VOLVOCINE.E. 63

develop into plates or discs of cells, not into spheres, and ultimately
resolve themselves into bundles of naked elongated cells, in which the
chlorophyll is transformed into a reddish pigment, each with a long
colourless beak, with a red ' eye-spot ' and two cilia. (Plate 22, Fig.
oa, a2.) About the same time that the oosphere is mature these
antheridia begin to move from the combined action of their cilia (Plate
23, Fig. 10), and then break up into separate antherozoids, which finally
become free, and move rapidly within the cavity of the sphere. (Plate
23, Fig. 5a!.) Assembling round the oospheres, they penetrate the
envelopes of the latter (Plate 22, Fig. 4), coalesce with their contents,
nnd the oosphere, thus fertilised, becomes an oospore, which soon develops
a cell-wall covered with conical stellate projections, and a second smooth
internal membrane. (Plate 23, Fig. 11.) The chloi-ophyll now gradually
disappears, and is replaced by an orange red pigment. In this condition
the oospore constitutes the Volvocr stellatus of Ehrenberg. It is liberated
by the decay of the parent-cell, and sinks to the bottom of the water
to hibernate. The subsequent history of these bodies has been traced
by Cienkowski, and more recently by Henneguay (" Journal de
Micrographie," Vol. II., p. 485, Bull. Soc. Philomath, Paris, July, 1878).

" Cohn believed that they must be dried up before germination was
possible. Henneguay has now observed that this is not so. In spring
the outer case of the spore (exospore) is ruptured, and the swollen con-
tents (endospore) project through the opening. The contents then
divide gradually into two, four, eight, sixteen, or more small cells, which
become bright green, each meanwhile acquiring two vibratile cilia while
still contained within the inner membrane of the spore. The cells, at
first in close apposition, separate further from one another by interposi-
tion of gelatinous hyaline matter, the outer membrane disappears, the
cilia become active, and the young Volvox, already containing some
elements larger than the others, and destined, in due course, to produce
daughter-spheres, moves freely through the water. ' The spores of
Volvox, therefore, germinate in water, and each of them produces a
single colony by a process of segmentation identical with that which
gives rise to a daughter-colony at the expense of a cell of the mother-
colony.'

"The sequence of asexual generations is repeated for many months,
and in the following autumn the alternation of generations is again
completed by the intervention of the processes just described."

Volvox globator. Linn. Syst. Ed. x.

Larger ccenobia, with very numerous cells (12,000), always
with daughter- ccenobia enclosed within the mother, evolved
without sexuality ; fructification dioecious ; the male ccenobia
nourishing numerous red fascicles of spermatozoa ; the female
ccenobia originating 20-40 sexual cells, which after fecundation
are resolved into as many red globose oospores, surrounded by a
hyaline stellate epispore (=Volvox stellatus, Ehr.).

SIZE. Ccenobium as much as 1 mm. diam.

Ehrb. Infus. 68, t. 4. Dujardin Zoophy. 312, iii. f. 25. Stein
Infus. p. 46. Rabh. Alg. Eur. iii. 97. Pritchard Infus. 526,
t. 20, f. 32-47. Busk. Trans. Micr. Soc. 1853, p. 31. Wil-
liamson Trans. Micr. Soc. 1853, p. 45. Currey Ann. Nat. Hist.
1859, p. 5. Dr. J. B. Hicks in Micro. Journ. 1861, p. 281 ; in

64 COCCOPHYCE.E.

Popular Science Review, vol. v. p. 137. A. W. Wills in
Midland Naturalist, Sept.- Oct., 1880. A. Bennett in Popular
Sci. Rev. 1878, p. 225.

Sphcerosira volvox, Ehr. Infus. (male). Pritch. Infus. p.
526. Williamson in Popular Sci. Review, vol. ix. p. 225.

Volvox stellatus, Elir. Infus. (oospore).

In clear pools, ponds, &c.

The relationship of Sphesrosi/ra -rolwx to Volrox globator has not been
satisfactorily determined (see Williamson), although there remains no
doubt of the existence of relationship. Some regard it as the male
form, but Professor Williamson considers it a peculiar condition of
Volvox.

For details of a successful experiment in keeping Volvox during the
winter see N. E. Brown in Gardener's Chronicle (1879 p. 599) and
" Ponds and Ditches," by M. C. Cooke, p. 63.

Plate XXII. jigs. 1-3. Volvox globator, after A. W. Wills; 4-5, after
Cohn. Explanation given above.

Plate XXIII. figs. 1-5. After A. W. Wills; 6, ideal section after
Williamson ; 7, after Wills — also fully described above ; 8-9, X 300
after Stein; 10, complete antheridium ; 11, stellate resting spore or
oosphere X 400 ( Volvox stellatus) • 12, spermatozoids X 600.

Plate XXIV. Male plants of Volvox, known as Spheerosira volvox,
after Williamson. Fig. 1, coeuobium ; 2, protoplasmic mass from the
coenobium, containing granules ; 3, mass divided in two ; 4, the same
divided into four; 5, the same divided into sixteen; 6. further division
into thirty- two, provided with movable cilia ; 7, discoid family revolving
within its mother-cell.

Volvox minor. Stein Infus. p. 47.

Ccenobia and the number of cells smaller ; the number of
daughter-ccenobia evolved without sexuality within the mother,
1-9 ; fructification sexual, monoecious ; many male cells
changing into bundles of spermatozoa; 5-10 female cells in
the same ccenobium, after fecundation, evolved into as many
oospores, surrounded by a smooth epispore (=Volvox aureus,
Ehr.).

SIZE. Variable, but smaller than the preceding.

Rabh. Alg. Eur. iii. 98. Stein Infus. t.

Volvox globator, of authors, in part.

Volvox aureus, Ehrb. Inf. 71, t. 4, f . 2 (oospore).

In similar places to the preceding.

Plate XXV. Volvox minor X 400 after Stein. Fig. 1, portion of
ccenobium with two young daughter families ; 2, coenobium with two
young daughter families enclosed in mother-cell ; 3, coenobium with five
young fertile cells ; 4, ccenobium wi^h six young fertile cells ; 5, a fer-
tile cell enclosing numerous vacuoles indicating the commencement of
subdivision ; 6, isolated daughter-family still enclosed in the mother-
cell ; 7, encysted cell — the Volvox aureus of Ehrenberg j 8, isolated
ordinary individual enclosed in a flask-shaped cell.

VOLVOCINE^E. 65

GENUS 40. EUDORINA. Ehrb. (1831.)

Coenobium oval, involved in a common tegument ; cells green,
globose (16-32), enclosed within a single membrane, bearing
vibratile cilia, often "with a red spot (eye-spot), distributed
around the hyaline sphere at equal distances apart. Asexual
propagation in all the ccenobia, the cells of which are divided
into 16-32 parts, and soon evolved into new ccenobia. Sexual
propagation in all the ccenobia, the cells being converted into
motionless oospores enclosed in a narrow epispore, afterwards
becoming red.

The most complete account we possess of the life-history of Eudorina
is that by H. J. Carter (Ann. Rat. Hist., Oct., 1858), of which the follow-
ing is a summary : — Unable to recognise this organism in its simplest
form as a solitary cell, nor any stage of segmentation prior to the third
degree of duplicative subdivision into 16 cells, he commences from this
period.

At this time, which we call the first stage, the Eudorina consists of an
ovoid green body, partially divided into the number of cells just men-
tioned, each of which is provided with a pair of cilia, which project
through a thin gelatinous envelope that surrounds the whole mass. It
is now about 1-llOOths of an inch long, i.e., not more than the diameter
of the Chlamy do coccus cell, and swims by means of its cilia, with the
small end foremost, and with a rotatory motion on its longitudinal axis,
as often from right to left as from left to right. An eye-spot is also
present in each of the four anterior cells, but seldom visible in the rest
at this period.

As development progresses each cell is provided with a spherical,
translucent utricle, an eye-spot midway between the cilia and the oppo-
site end of the cell, a contractile vesicle at the base of the cilia, and the
pair of cilia themselves.

During the second stage each of the cells again undergoes duplicative
division, and the whole organism becoming larger, they are separated
from each other, and being no longer subject to compression, become
sphaerical and enclosed respectively within distinct transparent capsules.
The Eudorina is now six times as long as in the first stage, and contains
32 green cells, whicb are evidently situated between two large ovoid,
colour'ess, transparent cells, one of which bounds a similarly shaped
cavity in the centre of the Eudorina, and the other is the original cell
wall, round which again is the newly secreted envelope. Thus we see
that the Eudorina is derived from a simple (daughter) cell, and that its
green cells have resulted from a duplicative subdivision of the green
matter which lined the cavity of this cell. Arrived at this state, which
we shall see is that of maturity, we also observe that the posterior part
of the envelope becomes crenulated, apparently from flaccidity.

After this, however, it again presents another phase, which may be
called the third, or last, stage of development. Here each cell again
undergoes a rapid duplicative subdivision into 16 or 32 cells, which, in
the group, assume a more or less oblong figure respectively, and thus the
Eudorina's length is increased to 10 times that of its first stage. Tbe in-
ternal structure now gradually breaks clown before the external envelope,
when for a short time the groups may be seen swimming about the cavity
thus formed, till at last the envelope bursts and they become liberated.
What becomes of them afterwards he could not state from observation,
but the green cells having been greatly reduced in size by the latter sub-

66 COCCOPHYCE^E.

divisions it is probable that many of the groups, if they do not form new
individuals, sooner or later become disintegrated, and the Eudorina, thus
eventually perishes.

When, however, the process of impregnation takes place, the division
stops at the second stage, that is when the Eudorina consists of 32 cells
of the largest kind, each of which is about !-18<i6th of an inch in dia-
meter within its capsule, which is therefore a little larger. The process
is as follows : —

At a certain period after the second stage has become fully developed
the contents of the four anterior cells respectively present lines of dupli-
cative subdivision, which radiate from a point in the posterior part of the
cell (in the subdivision of other cells the lines of fissiparation tend
towards the centre of the cell). These lines, which ultimately divide
the green contents of the cell into 64 portions, where the division stops,
entail a pyriform shape on the segments, from whose extremities a mass
of cilia may be observed waving in the anterior part of the cell of the
parent, while yet her own pair of cilia are in active motion, and her eye-
spot still exists in situ on one side of her progeny, thus showing that the
latter may be almost fully formed before the parent perishes. At length,
however, this takes place, and the progeny (Spermatozoids) separate from
each other, and finding an exit, probably by rupture, through the effete
parent cell and her capsule, soon become dispersed throughout the space
between the two large ovoid cells mentioned, where they thus freely come
into contact with the capsules of the twenty-eight remaining, or female
cells.

The form of the spermatozoid now varies at every instant from the
activity of its movements, and the almost semifluid state of its plasma.
Its changes, however, are confined to elongation and contraction ; hence
it is sometimes linear-fusiform, or lunular, at others pyriform, short, or
elongate. The centre of the body is tinged green by the presence of a
little chlorophyll, while the extremities are colourless, the anterior one
bears a pair of cilia, and there is an eye-spot a little in front of the middle
of the body, also probably a nucleus. It is about l-2700th of an inch
long and about one-fifth as broad.

Once in the space mentioned, the spermatozoids soon find their way
among the female cells to the capsules, of which they apply themselves
most vigorously and pertinaciously, flattening, elongating, and changing
themselves into various forms as they glide over their surfaces, until they
find a point of ingress, when they appear to slip in, and, coming in con-
tact with the female cell, to sink into her substance as by amalgamation.
This author explains that there was some difficult)' in seeing the act of
union, but of the act itself he entertained no doubts. Eudorina in this
stage also may frequently be seen with all the four anterior cells absent,
and only a few spermatozoids left, most of which are motionless and
adherent to the capsules, indicating that the rest have disappeared in the
•way mentioned. Lastly, many Eudorinu; in this stage may be observed
with not only the four anterior cells absent, but with hardly a spermato-
zoid left, indicating that the whole had passed into the female cells or
had become expended in the process of impregnation.

What changes take place in the Eudorina after this he had not been
able to discover. At the time the female cells appear to become more
opaque by the incorporation of the spermatozoids, and the crenulated
state of the posterior part of the envelope in this stage seems also to in-
dicate an approach to disintegration.

While undergoing impregnation the female cells always contain from
2 to 4 nuclei, as if preparatory to the third stage of development into
which they are sometimes actually seen passing, with the spermatozoids
present and scattered among them ; but the effect of impregnation
generally seems to arrest this stage, and thus save the species from
that minute division which leads to destruction.

VOLVOCINE.E. 67

The author cited then goes on to explain how he conceives the other
stages of the Eiidorina are passed, which he had not the opportunity
of observing. The whole memoir is one of great interest, and will
well repay perusal by those who are investigating this subject.

Eudorina elegans. EJirb. Monats. Berl., 1831, p. 78.

Coenobia oval, cells usually 32, globose, either scattered or
quaternate, eight at each pole, distributed in three parallel
circles, at equal distances from each other, around the periphery
of the ccenobium.

SIZE. Ccenobium -04--15 mm. long. Cells -018--022 mm.
diam.

Rabh. Alg. Eur. iii. 99. Ehrb. Infus. 63, t. iii. Pritchard
Infos, p. 520. Carter, in Ann. Nat. Hist., Oct., 1858.

Pandorina elegans, Dujard. Zoophy., p. 317.

In standing water.

Formerly found at Hackney and Hampstead, most abundant in the
spring of the year, but doubtless quite extinct at both places. " Clusters
are of ten seen," says Pritchard, " in such amazing numbers along with
Volvox and Chlamydomonas pulvisculus as to render the water of a
decided green colour, especially towards the edges."

Plate XXVI. fig. 1. a, 16-celled family; 2, sixteen-celled family
dividing into a 32-celled family ; 3, part of a family, showing division in
pairs ; 4, 32-celled family divided into daughter-families; 5, one-celled
daughter-family. All after Stein. 6, colony \\ith three spermatic
cells, having burst j 7, spermatic cells X 400 ; 8, spermatic cell X 800 ;
9, spermatozoids X 800. After Carter.

GENUS 41. PANDORINA. Ehrb. (1830.)

Ccenobium globose or subglobose, invested by a broad colour-
less hyaline tegument ; cells green, granulose, globose (16, 32,
or 64), included within a single rather thick membrane, bearing
two vibrating cilia, with or without a red spot, aggregated in a
botryoid manner.

Propagation the same as in Eudorina.

Henfrey's emended character of this genus was in the following
terms : — " Frond a microscopic, ellipsoidal, gelatinous mass, containing,
embedded near the periphery, sixteen or more biciliated, permanently
active gonidia, arranged in several circles perpendicular to the long axis
of the frond. The gonidia almost globose, with a short beak-like
process, a red spot, and a pair of cilia which project through the
substance of the frond to form locomotive organs upon its surface.
Reproduction — I., by the conversion of each gonidium into a new frond
within the parent mass ; II., by the conversion of the gonidia into
encysted resting spores, which are set free and (?) subsequently ger-
minate to produce new fronds." — Quart. Micro. Journ. (1856), p. 49.

68 COCCOPHYCE^E.

Fandorina morum. E7ir. Inf. p. 53, t. IT. f. 33.

Coenobium globose. Cells green, 16-32, arranged about the
periphery. In the forms which produce the resting spores, the
cells are crowded together in the centre. Resting spores after
becoming encysted bright red.

SIZE. Ccenobium "2 mm. Cells -01--015 mm. diam.

Rabh. Alg. Eur. iii. 99. Henfrey Micr. Trans. (1856) p.
49, t. 4. Pringsheim Monatsb. Berlin, Oct., 1869. Ann.
Nat. Hist. v. (1870) p. 272. Pritchard Infus. pp. 157 and 517,
t. xix. fig. 59-69. Braun Rejuv. pp. 169-209.

In standing water.

" Fronds hyaline from about 1-80" downwards. Gonidia either 16,
and then arranged in four circles of 4, or 32 and then in five circles, two
at the poles of 4, and the intermediate three of 8 gonidia, which in the
perfect form stand near the periphery, and wide apart. In the forms
which produce the resting spores the gonidia are crowded together in
the centre. The gonidia are green, but the contents of the resting
spores, after they have become encysted, are converted into oily and
granular matter of a bright red colour." — Henfrmj.

Pringsheim, in his memoir "on the pairing of Zoospores,"* makes
special reference to this species. He says that asexual reproduction
takes place in Pandorina, as in other multicellular Volvocineae, by the
formation of a perfect young plant in each cell of the mother plant. By
the gradual dissolution of the general envelope and of the special mem-
brane of the mother-cells, the young plants become free, and escape. In
sexual reproduction, as in the asexual, the membrane of the old plant
swells, and sixteen young plants are formed. The young plants, how-
ever, are (at least in part) not neuter, but sexual, and either male or
female. Whether the mother plant is monoecious or dioecious is difficult to
determine, because the male and female plants are externally alike, and
can hardly be distinguished with certainty during copulation. There is
no striking difference in structure between the sexual and asexual
plants, although, amongst the former, plants with less than sixteen cells,
especially with eight cells, are oftener produced. Moreover, the dissolu-
tion of the membrane of the mother-cell proceeds more slowly than in
the case of neuter plants, one result of which is that the young asexual
plants vary much in the extent of their growth, and continue united in
groups of different sizes for a long time after their formation, according
as a greater or less number of them have happened to become free from
the gelatinous mass in which they were embedded.

As the individual groups are at first motionless, and the mother plant
loses its cilia during the formation of the young ones, the entire group
is at first entirely quiescent. But afterwards the young sexual plants,
like the neuter ones, produce upon each of their cells two cilia, which
commence their motion as soon as the enveloping mucus admits of it,
and thus ultimately the entire group assumes a state of active rota-
tion. During the rotation of the groups the same process of expan-
sion and dissolution takes place in the membrane of the sexual plants
as occurred in the mother plant ; but the contents of the cells of the
Bexual plants do not undergo division, but combine to form a single
zoospore, which becomes free by the rapid dissolution of the mem-
branes. In their general structure these zoospores differ in no way

* Monatsbericht, Eoy. Acad. Sciences, Berlin, Oct.. 1869. Translated
in "Annals of Natural History," Vol. V. (1870), p. 272.

VOLVOCINE-cE. 69

from other zoospores. At their colourless apex they exhibit, like
other zoospores, a red body placed on one side of the apex, and two
long vibrating cilia, by which they move in the manner common to
zoospores. The individual zoospores exhibit no marked differences,
except that they vary in size within tolerably wide limits, but not in a
manner to indicate the existence of two different sorts.

Amongst the groups of isolated zoospores of different sizes some are
at last seen to approach one another in pairs. They come into
contact at their anterior hyaline apex, coalesce with one another, and
assume a shape resembling a figure of 8. The constriction which
marks their original separation disappears by degrees ; and the paired
zoospores form at last a single large green globe, showing at the cir-
cumference no trace of their original separation. It may be seen,
however, that the globe is larger than the individual neighbouring zoo-
spores, that it has a strikingly enlarged colourless mouth spot, with
two red bodies on the right and left, and that it is furnished with four
vibrating cilia originating in pairs near the two red spots. The four
cilia, however, soon become motionless, and together with the red spots
disappear.

This act of conjugation occupies some minutes from the first contact
of the zoospores to the formation of the green globe. The latter
becomes the oospore, which, after growing slightly larger, and assuming
a red colour, germinates after a long period of rest, and brings forth a
new Pandorina. There is hardly any appreciable difference, except in
size, between the male and female zoospores. Most frequently a small
zoospore pairs with a larger one ; but two of equal size often unite.
Probably both the females and the males vary much in size, the former
more so than the latter.

With regard to the entire plants from which the zoospores are pro-
duced, there is little doubt that those of the largest size are females ;
but the sex of the smaller and middle-sized ones cannot be determined
with any certainty. The germination of the oospore is like that of other
Volvocinete, especially resembling in its early stage the germination of
the resting spores produced by the microgonidia of Hydrodictyon utri-
culatiim. The oospore bursts, and produces a single large zoospore (in
rare cases two or even three), which divides into sixteen cells, and
becomes a young Pandorina.

Plate XXVII. fig. 2. Pandorina morum — a, a very small family ; 6,
c, sixteen-celled families ; d, eight-celled family ; e, solitary cell ; /, the
same, further magnified, showing process of subdivision ; g, 32-celled
family ; h, small family undergoing division ; i, 16-celled family
divided into sixteen daughter families. All after Stein X about 500.

GENUS 42. GONIUM. Mutter. (1873.)

Coenobinin quadrangular, tabular, angles rounded, formed
from a single flat stratum of cells, girt by a broad hyaline
plano-convex tegument. Cells 16 (central 4, periplierical 12 J,
polygonal, bright green, becoming with age disordered, granu-
lose, connected by the produced angles, chlorophyllose vesicle
central, furnished with colourless contractile vacuoles, and two
long exserted cilia.

Propagation by repeated division of the cytioplasni.

70 COCCOPHYCE.E.

Gonium pectorale. Mull. Vermium,p. 60.

Coenobium flattened, quadrangular, composed of 16 green
cells, furnished with vibratile cilia.

SIZE. Coenobium, from -05 mm. Cells from '01 X '007 mm.

Babh. Alg. Ear. iii. 99. Mull. Anim. Inf. t. 16, f. 9-11.
Ehrb. Infus. 56, t. 3, f. 1. Dujard. Zoophy. p. 318. Focke
Studien, 30, t. 4, f. 7, 8. Fresen, Abhand. der Senck, p. 191,
t. 8. Cohn Nova Acta, xxiv. p. 169, t. 18, f. 9-27. Prit-
chard Infus. p. 518.

In stagnant water.

The fullest account of Gonium is that by Cohn, published many years
ago, but nothing has been added to its history since. The following is a
summary of his observations : —

Each family is invested with a colourless mucous sheath which is diffi-
cult to be seen without adding some colouring matter to the water, as
there appears to be no tegument. Seen from above, it is a quadrilateral
tablet with rounded corners, or from the side elliptical. The primordial
cells are sixteen in number, four occupying the centre disposed as a
square, and three on each side external to these. The central cell of the
three on each side is seta little nearer towards the centre. The cells are
somewhat polygonal, the four central being hexagonal, and the twelve
external pentagonal. When young the angles can scarcely be dis-
tinguished. This regular polygonal form indicates that each cell is sur-
rounded by a firm membrane, which retains them in a fixed form. The
investing membrane may also be detected at the angles of the cells, from
each of which it is extended in a short tubular process, which is quite
colourless. These pi'ocesses are joined to those of contiguous cells, so
as to link them all together. These processes are not visible in imma-
ture families, being subsequently developed.

In other points the organization, of the cells resembles Chlamydomonas.
Their contents consist of protoplasm, coloured by chlorophyll, when old
containing numerous corpuscles, a central darker corpuscle, and often
several vacuoles. Each cell is furnished with two cilia, which proceed
from the protoplasm, through perforations in the cell wall.

The movements of the coenobium resemble those of Stephanosphcera ;
it revolves on its short axis, so that its polar aspect is that of a rotating
surface, whilst its equatorial is linear.

In the development by subdivision only the cell-contents are con-
cerned. The fission takes place by four successive stages, or genera-
tions, in each of which bisection of the cells occurs, so that ultimately
each primordial cell is subdivided into sixteen portions. When the sub-
division is completed by the construction of these sixteen small cells,
they are seen to occupy the same position and arrangement in the
mother-cell as in the parent coenobium.

The primordial cells of the newly formed coenobia appear unconnected
with each other. The movement of the pai'ent ccenobinm continues
until the last stage of fission is completed, when it ceases, and the
young daughter coenobia commence a movement within the parent cell,
sometimes appearing as a disc, and at others as a line, according as the
surface or the edge is turned towards the spectator.

At length the mother-cell ruptures, and the young colony escapes into
the water, moves about freely, and starts on an independent existence.
Supposing that a young Gonium after twenty-four hours is capable of
development by fission, it follows that, supposing the conditions favour-

VOLVOCINEJS, 71

able, a single colony may on the second day develop 16, on the third
256, on the fourth 4,090, and at the end of the week 268,435,456 other
organisms like itself.

It has been supposed that some of the cells become detached from the
mature coenobium and pass into a resting condition, but this has not been
positively demonstrated, so that figuration is the only mode of repro-
duction at present known.

A fuller abstract of this paper by Cohn (from " Nora Acta," Vol.
XXIV., p. IGity is given in Fritchard's Infusoria (p. 153).

Plate XXVII. fig. 1. Goniuni pectoral?. — a, b, c, families in different
positions X 400 ; d, e, the same, rather more highly magnified ; /, family
before division; g, family of 16 cells divided into 16 daughter families ;
d to g after Stein.

GENUS 43. STEPHANOSPHJERA. Cohn. (1852.)

Coenobium throughout its whole life rotating and moving,
composed of 8 green cells, bearing two vibratile cilia, disposed
at equal distances around a circle, enclosed in a common
colourless hyaline, globose vesicle.

Propagation, both by macrogonidia arising from the eight-
fold division of the green cells, bearing two cilia, with a lateral
red spot, congregated in families of eight ; and by niicrogonidia,
very much smaller, produced by multiplied division, at first re-
volving within the common vesicle by the action of four cilia,
afterwards free, escaping singly.

Stephanosphaera pluvialis. Cohn Bedrvigia i.,p. 11.

Cells globose, elliptic or fusiform, often at each extremity
spreading out in mucous rays.

SIZE. Ccenobium -026--052 mm. Cells -006--012 mm.
diani .

Rabh. Alg. Eur. iii. 100. Currey in Micr. Journ., 1858, vi.
p. 131, t. 6, f. 1-27. Cohn Zeitschr. fur Wiss. Zool., 1852,
iv. p. 77. Archer Micr. Journ., 1865, p. 116. Pritchard Inf.
p. 529, t. 19, f. 38-58.

In hollows of rocks, and in pools after rain.

StepJianospJifsra was first observed in 1850 in Germany, and since in
many places, including the British Isles.

It consists of a hyaline globe, containing eight green primordial cells,
arranged in a circle in its equator. The globe rotates upon an axis per-
pendicular to the plane in which the primordial cells are arranged, and
moves actively in space by the aid of cilia, two of which proceed from
each of the primordial cells, and pierce the hyaline envelope. The
primordial cells divide first into two, then four, and lastly into eight
portions ; these portions separate from each other in a tangential direc-
tion, thus forming a disc round which a cellular membrane is developed.
Two cilia are produced upon each segment, and thus eventually eight
young individuals are formed, which ultimately escape by fissure of the

72 COCCOPHYCE^;.

parent globe. This process was observed to occupy about twelve hours.
Cohn also observed the division of each of the eight primordial cells into
a great number of microgonidia, which swarm within the globe, and
escape from it. Under certain circumstances each of the eight cells
secretes a cellular covering, and swims about in the interior of the
globe in the form of free Chlamydococcus-like cells. Eventually they
escape either by fissure of the globe or by its gradual dissolution, lose
their cilia, form a thicker membrane, become motionless, and accumu-
late at the bottom of the vessel. If the vessel be permitted to become
dry, and afterwards filled with water, motile Stephanospheera reappear,
from which it seems probable that the green globes are the resting cells.

The resting cells vary much in size, and it is supposed that they
grow considerably after attaining a state of rest. The colour is deep
green, sometimes yellowish or olive, and they possess a nucleus.

The dried resting spores absorb water, and their contents gradually
fill up the cavity of the containing membrane, and become cloudy and
granular ; the border becomes yellowish, and the red colouring matter is
contracted in the centre. The cells then begin to divide and pass
through successive stages, as shown on the plate (Plate 28, figs. 13
to 17). The four daughter-cells begin to quiver, and endeavour to
separate from each other. Two cilia are now apparent at the pointed
extremity of each of the four cells (fig. 19), by the action of which the
group begins to move as a whole ; utlimately all trace of the enveloping
membrane disappears, and one by one the daughter-cells escape and
become free. At the moment of escape their diameter never exceeds
•01 mm., but they soon enlarge to a diameter of '013 to *015 mm.

The length of time which elapsed between the immersion of the
dried resting spores and the first appearance of the motile cells varied
from nine to twenty-four hours. It was observed that those resting
spores which did not produce zoospores within six days never did so
afterwards, although they continued to live, and seemed perfectly
healthy. Zoospores produced in November did not advance beyond the
first stage. Others produced in March remained only a few hours in
that condition, after which time a delicate membrane was formed
round the body of the primordial cell ; this membrane was at first
closely attached to the cell, but became gradually enlarged, by absorp-
tion of water, into a colourless enveloping vesicle, usually globular,
but sometimes oval, having two openings, through which the cilia
penetrate. In this condition they attain a diameter of '017 to '022 mm.,
and are not distinguishable from encysted forms of Chlamydococcus
pluvialis. Other zoospores, produced in April, attained a larger size,
and the protoplasm of the primordial cell, instead of retaining its con-
tinuous outline, became elongated here and there into simple or forked
mucilaginous rays, which were either colourless or green from the presence
of chlorophyll. These rays are probably produced by the protoplasm ad-
hering at certain points to the surrounding membrane, and being carried
outwards by its growth. The Chlamydococcus like form only lastei a
few hours ; towards the evening the zoospores mostly began to divide.
The rays are drawn in, the primordial cell becomes round, it then elon-
gates, is constricted, and ultimately is divided into four quadrants.
These are again bisected, and eventually eight wedge-shaped portions are
formed, whose contour lines, like the spokes of a wheel, meet in the
middle.

Here is to be noted a distinction between the Stej}hanosj)h(?ra and
Chlamydococcus; for while in the latter the individual portion^ of a
primordial cell separate entirely from each other, each developing its own
enveloping membrane, and ultimately escaping as a unicellular indi-
vidual, in the former the eight portions remain united as a family. The

VOLVOCINE.E. 73

coloured contents of the individual portions become drawn back towards
the periphery in centrifugal direction, a colourless plasma remaining
about the central point ; this disappears at first in the centre, a cavity ia
formed in the middle of the disc, and as this enlarges the eight portions
assume the form of a wreath, consisting of eight globular or ellipsoid
bodies in close contact, usually not exactly in one plane, owing to the
outer membrane not having expanded in proportion to the enlargement of
the plasma. The original cilia continue active, causing the motion of
the whole organism, until the eight portions are completely individualized,
and then their motion ceares. The separate parts of the plasma now form
eight independent but closely packed membraneless primordial cells.
shortly afterwards a delicate membrane common to them all is secreted
beneath the mother-cell membrane round the disc formed by the primordial
cells. This membrane is at first in contact, but afterwards becomes further
and further removed as it swells and tends to assume a globular form. By
the motion of the cilia the mother-cell membrane is thrown off, and the
young family escapes into the water. When the Chlamydococcus-like
unicellular Stephaiiosphcera has commenced its Division early in the
evening, the division into eight is perfected during the night, and early
in the morning the young family quits its cast off mother- cell membrane.

In the course of the day the individual primordial cells and their
common investing membrane grow until the latter attains a diameter
of "01 to '048 mm. During this growth the shape of the primordial
cells is changed by the formation of various prolongations, but in the
course of the afternoon they again become round, and during the even-
ing division commences in them precisely similar to the process in the
unicellular Stephanosphcera. On the following morning we find eight
young families. It is calculated that in eight days, under favourable
circumstances, 16,777,216 families may be formed from one resting cell
of Stephanosph&ra.

We have given but a barren outline of the history of this little plant,
but for further information must refer the student to Cohn's Original
Memoir in Siebold and Kolliker's Zeitschrift fur Zoologie, 1852, p.
77. Translated in the "Annals of Natural History," 2nd series. Vol. X.,
pp. 321 and 401. Also Cohn and Wichura's subsequent memoir " Ueber
Stephanosphrera " in Nova Acta Acad. Leop. Car., 1857, part I., Vol.
XXVI. Of which an abstract is given by Currey in " Quarterly Journal
of Microscopical Science," Vol. VI. (1858), p. 131. Also an admirable
summary by Archer in the " Quart. Journ. of Microscopical Science "
for 1865, p. 117, with additional observations by himself.

Plate XXV I II. jig. 1. Polar view of family with globose primordial
cells ; 2, equatorial view, with fusiform primordial cells ending in
mucous filaments ; 3, the same, with primordial cells collected on one
side ; 4, commencement of formation of macr ogonidia ; 5, all eight pri-
mordial cells divided in. fours ; 6, division advancing so that each
primordial cell consists of eight cuneate segments ; 7, further advanced
in division, movement in the mother-cell having commenced ; 8,
division completed, eight young individuals revolving in the mother-
cell ; 9, the eight original primordial cells broken up into mierogonidia j
10, young Stephanosphcera, (figs. 1 to 10 X 300) ; 11, mierogonidia after
exit from mother-cell X 500; 12, full-grown resting cells ; 13, commence-
ment of division in resting cell ; 14 to 19, successive stages in division
of resting cell ; 20 to 22, naked zoospores ; 23, 24, encysted zoospores ;
25 to 27, division of encysted zoospores ; 28, young eight-celled family
resulting from division of encysted zoospore ; 29, 30, young families,
all after Cohn X 400 ; 31, amaaboid condition of primordial cells, after
Archer.

74 ZYGOPHYCE^E.

ORDER II. ZYGOPHYCE^.

Either unicellular or multicellular Algas, with terminal vege-
tation, and destitute of true ramification. Cells single, or
segregate, or geminate, or united in a series. Chlorophyll-mass
for the most part distributed in plates, or bands, including one
or more amylaceous granules.

Multiplication by division of the cells in one direction.

Propagation by zygospores resulting from the conjugation of
two cells.

Consult here Dr. A. De Bary's " Untersuchungen uber die Familie
der Conjugaten." Leipzig, 1858.

FAMILY I. DESMEDIE^S.

Unicellular Algas. Cells for the most part compressed,
single, or segregate, or geminate, or a larger number united in
a band, or filament ; variable in form, usually constricted in the
middle, so as to constitute two symmetrical semi-cells.

This large and interesting family is designedly excluded from the
present work, as it is proposed to treat them separately. As so many
students confine themselves exclusively to this family, this proposal
will doubtless commend itself. The excellent text book by J. Ealfs has
long been the standard for English students, and would be so still but
for its scarcity, and the large number of additions in. the interval since
its publication.

FAMILY II. ZYGNEMACEJB.

Multicellular Algas. Cells cylindrical, equal at both ends ;
fructiferous cells more or less tumid, or inflated, all closely
conjoined in filamentous families, forming an articulated simple
thread, with a centr;.! cytioblast involved in radiating proto-
plasm. Cell walls lamellose.

Chlorophyll-mass effused, or of a definite form, often forming
a spiral band.

Vegetation by repeated transverse division.

Propagation by zygospores, resulting from the conjugation of
two cells. Conjugation taking place in three ways, lateral,
scalariform, and genuflexuous.

This family is sub-divided into three sub-families, according to the
character of the reproductive process : —

I. ZYGNEME.E.

II. MKSOCARPE.E.

III. GONATONEME.E.

ZVGNEMACE.E. 75

We append here De Bary's scheme of classification of this Order,
which he terms " Conjugate."

" Cells of limited growth, propagated by unlimited repeated biparti-
tion (tripartite in Craterospermum) in the same direction, free or con-
nected in single rows, chlorophyll in parietal bands, axile plates, or
radiating bodies, in pairs. Cell-wall cellulose or gelatinous.

"Fructification. By copulation a zygospore arises of a different form
from its mother-cells. No asexually produced swarmspores.

" SUBDIVISIONS.

"I. Mesocarpeee. Zygospore the shape of the mother-cells, not con-
tracted, separating by three or five partitions into a central firm-walled
resting-spore and two or four lateral decaying cells. (Cells cylindrical,
united in threads, with axile plates of chlorophyll.)

"II. ZygnemefS. Zygospore undivided and mostly contracted, passing
into the resting condition, afterwards developing into a germ-cell divided
into a basal cell, and a thread-cell capable of division. (Cells cylin-
drical, united in threads.)

" III. Desmidiece. Zygospore of the form of the Zygnemece, develop-
ing into a germ-cell, or divided into 2 or 4, each of which separates into
two equal daughter-cells capable of division. (Cells usually consisting
of two symmetrical halves, of very various form, free or united.)"

We have adopted a similar arrangement, with the exception of the
present exclusion of the Desmidiece, and the addition of a small sub-
family, the Gronatonemece, which dates from a period subsequent to
De Bai'y's Memoir.

Conjugation in the present family is the union of two cells, either of
separate filaments, or of the same filament, the result being the forma-
tion of a zygospore. The cells containing the male and female element
cannot at present be distinguished from each other, although De Bary
states that he has observed a constant difference between the fertile and
sterile cells of a species of Spirogyra. Usually all the cells of one
filament appear to be either giving or receiving cells, so that the male
and female filaments would seem to be distinct, but this requires more
certain confirmation, inasmuch as in such of the species of Sjjirogyra as
exhibit lateral as well as scalariform conjugation, all the cells in one
filament cannot be of the same kind.

" The first perceptible change in a cell about to produce a resting.
spore appears to be a loosening of the primordial utricle from the outer
wall, and a contraction of it upon the cell-contents, which thus are
crowded together and more or less deformed. Simultaneously with
this, or a little after or before it, the side wall of the cell is ruptured, and
a little pullalation or process is pushed out, which directly coats itself
with cellulose and rapidly enlarges to a considerable diameter, at the
same time growing in length until it meets a similar process pushing out
from an opposing cell, or has attained as great a length as its laws of
development will allow. When two processes meet they become fused
together, the end walls are ruptured, and the contents of one cell pass-
ing over are received within those of the other, or else the contents of
both cells meet within the connecting tube, arid there fuse together.
This is the more common mode of conjugation, in which two cells of
distinct filaments become joined together by a connecting tube. It is
evident that, if the filaments are fertile to their fullest extent, there
will be as many of these connecting tubes as there are pairs of cells
in the filaments, and a ladder-like body will be formed, the ori-
ginal filaments corresponding to the side pieces, the connecting tubes
to the rounds. Hence this method of conjugation has received the
name of scalariform.

" In the so-called lateral conjugation, instead of cells of different
filaments joining, adjacent cells of one filament unite together to com-

M

76 ZYGOPHYCE.E.

plete the process. The union of the two cells appears to take place in
several ways. In accordance with one plan, connecting tubes, pushed
out from near the ends of the cells, grow for a short distance nearly at
right angles to the long axis of the filaments, and then bend at a right
angle to themselves, so as to run parallel to the filament cells. The ends
of these processes are, of course, opposed to one another, and coming in
contact, fuse together so as to form a continuous tube for the passage of
the endochrome. Another method by which neighbouring cells are
sometimes connected is by the formation of coadjacent pouch-like en-
largements of the opposing ends, and a subsequent fusion of these
newly-formed enlargements by the absorption of the end wall between
them."

" There is still another method of conjugation, the so-called genuflexu-
ous, in which, instead of a connecting tube being formed as the medium
of union, two cells of opposing filaments become sharply bent back-
wards, so that their central portions are strongly thrust forward as
obtuse points, which, coming in contact, adhere, and allow of a passage-
way between the cells being made by the absorption of their cohering
walls."— Wood's F. Water A Ig OB, p. 161.

Hassall says that the conjugation in Zygnwmacece results in the pro-
duction of " a dark body, of either an oval or circular form, and en-
veloped in membrane, which Vaucher, Decaisne, and Jenner regard as
the true spores, but which Agardh declares resolve themselves after a
time into zoospores, an opinion in which I concur, applying the term
sporangia to them." It need scarcely be added that this view is erro-
neous, the resulting body germinating direct after a period of rest, and
termed a zygospore.

The same author makes also another statement, rather vaguely stated,
which is not confirmed by experience. " It is curious to remark that
the cells in one part of the same filament will part with their contents
and remain empty, while in another they will be the recipients of the
contents of the cells of another filament." His remarks on agamaa-
sporous Conjugates will be illustrated under the sub-family Gonatonemeos.

Sub-Family 1. ZYGNEME^E.

Cells cylindrical, united in threads. Zygospore undivided,
and mostly contracted, passing into the resting condition, after-
wards developing into a germ-cell, divided into a basal cell, and
a thread-cell, capable of division.

As hereafter explained, this sub-family differs from the Mesocarpece
chiefly in the development of the spore, which is not surrounded, or
accompanied, by two to four deciduous lateral cells.

GENUS 44. ZYGNEMA. Kutz. (1843.)

Cells with two axile many-rayed chlorophyll bodies standing
near the central cell nucleus, each containing a starch-grannie,
or quite filled with dense granular contents, surrounding two
starch-granules lying near the centre, (a) 'zygospore in the
bladdery middle space between the ladder-like united pairing
cells (£), copulation ladder-like, or lateral between two cells
of the same thread.

ZYGNEMACEJE. 77

In certain of the species of this genus the zygospores are produced in
the conjugating canal, and in other species in one or other of the con-
jugating cells. This fact is taken advantage of in the following arrange-
ment : —

A. Zygospores produced in conjugating canal.

* Sporoderm scrobiculate.

1. Zygnema pectinatum, Ag.

** Sporoderm even.

2. Zygnema Ralfsii, Kutz.

3. Zygnema parvulum, Kutz.

B. Zygospores produced in one or other of the conjugating cells.

* Sporoderm punctate.

4. Zygnema cruciatum (Vauch.).

5. Zygnema stellinum (Vauch.).

6. Zygnema Vaucherii, Ag.

7. Zygnema anomalum (Hass.).

** Sporoderm even.

8. Zygnema leiospermum, DeBary.

9. Zygnema insigne, Kutz.

A. Zygospores produced in conjugating canal.
Zygnema pectinatum. Ag. Syst. p. 78.

Sterile cells 1-2 times as long as broad.

Zygospore globose or broadly elliptic, dark olive, scrobicu-
late, formed in the canal of conjugation.

SIZE. Cells -03-'035 mm. diam. (sometimes less), zygospore
•04 mm. diam.

DeBary Conj. p. 77, t. 1, f. 15; 19, t. 8, f. 13. Gray
Arr. i. 1296.

Conjagata pectinata, Vauch. Conj. p. 77, t. 7, f. 4.

Conferva bipunctata, Eng. Bot. t. 1610.

Conferva decussata, Dillw. Conf. Syn. p. 5, (?)

Zygogonium pectinatum^ Rabh. Alg. iii., 252. Kirsch. Alg.
Schl. p. 126.

Tyndaridea conspicua, Hass. Alg. t. 39, f. 1, 2, Ann. Nat.
Hist, xii., 187, t. 7, f. 17.

Tyndaridea immersa, Hass. Alg. t. 39, f. 3. Ann. Nat. Hist,
xii. 188, t. 7, f. 19.

Tyndaridea decussata, Hass. Alg. t. 39, f. 6. Ann. N. Hist,
xii., 188, t. 7, f. 18.

Zygogonium conspicuum, Kutz. Tab. v. t. 12, f. 2.
.Zygogonium immersum, Kutz. Tab. v. t. 12, f. 5.

Zygogonium decussatum, Kutz. Tab. v. t. 11, f. 4.

Tyndaridea pectinata, Eng. Fl. v. p. 361 ; Eng. Bot. ii. t.
2597, Harv. Man. 142 ; Mack. Hib. 231.

Zygnema bipunctatum, Grev. Fl. Ed. 320 ; Fl. Devon, ii. 50.

In still waters.

As noted above, we include here three of Hassall's species of Tynda-
ridea. Kirschner does the same, with the addition of Kutzing's Z ano-

78 ZYUOPHYCEJ2.

malum, which, however, is not the Tyndaridea anomala of Ralfs and
Hassall, as will be evident hereafter. There does not seem to be even
a sufficient difference to justify the maintenance of the different forms
as varieties. This is the only British species, as far as at present known,
with a scrobiculate zygospore, produced in the channel of conjugation.
We have followed De Bary in referring this species to Zygnema instead
of to Zygogonium. It is unnecessary in a work of this kind to discuss
the reasons which have induced us in this, and similar cases, to adopt
such a course. It may be well to caution the student at once that he
will only waste time in the endeavour to determine species from the
sterile threads. In the present, for instance, he would soon discover
how hopeless it is to attempt to discriminate between the vegetative
cells of this and some of its allies, without the knowledge also of the
method in which the zygospore is formed, and its character when de-
veloped.

Plate XXIX. Jig. 1. a, portion of sterile thread X 400 ; 6, threads
in conjugation X 200; c, zygospore X 400.

Zygnema Ralfsii. (Kutz.) De Bary Conj. p. 77.

Sterile cells 2-| to 3 (rarely 4) times as long as broad .

Zygospore compressed ellipsoid, twice as long as broad,
produced in the inflated conjunctive canal. Sporoderm even.

SIZE. Cells -016--017 X '02mm. Zygospore -025 X -015 mm.

Eabh. Alg. Eur. iii. p. 252.

Zygogonium Ralfsii, Kutz. Tab. v. t. 11, f. 2. Kirsch. Alg.
Schl. p. 127.

Tyndaridea Ralfsii, Hassall Alg. p. 165, t. 39, fig. 4, 5.

Ann. Nat. Hist. xii. p. 188, t. 7, f. 20. Jenner Fl. Tunb.
Wells, p. 182.

In pools and streams.

This is the only other British species of Zygnema in which the zygo-
spore is produced in the channel, except the succeeding one, which is at
best doubtful. It appears to be uncommon, at least in conjugation.
First found by Mr. Ralfs at Penzance. It is still to be obtained in its
old habitat, and it appears to have been discovered in France and Ger-
many.

From the brief note of De Bary, he seems to recognise this as a dis-
tinct and veritable species of Zygnema, according to his interpretation of
that genus.

Plate XXIX. fg. 2. a, portion of sterile thread X 400; b, threads
in conjugation X 400.

Zygnema parvulum.

Sterile cells 4 to 6 times as long as broad, zygospore globose,
produced in the conjunctive canal.

SIZE. Cells '02--022 mm. Zygospore about equal.

Zygogonium parvulum, Kutz. Tab. v. t. 12, f. 4. Kutz. Sp.
Alg. p. 447.

Zygnema ordinarium, Berk. Glean. 1. 12, f. 1. ' Harv. Man. 144.

In standing pools.

If the Zygnema ordinarium of Berkeley's " Gleanings " can be re-
ferred to Zygnema parmdum, that is, as far as we have ascertained,

ZYGNEMACE^E. 79

the whole evidence upon which this species is inserted. The figure in
the " Gleanings," as represented, in part, on our plate 29 (fig. 3c), is so
manifestly insufficient, without measurements, that the species is intro-
duced with some hesitation. The rest of our figures, and the descrip-
tion, are derived from Continental sources, and represent Kutzing's
species.

Berkeley says of the plant he has figured : — " The filaments are
quite unattached, and float in a rather dull green mass at the top of the
water, which (at least in a state of fructification) is but little mucous,
adhering imperfectly to paper in drying. But as the plant has only been
once met with, and it is well known that other species of Zygnema are
much less mucous in a state of fructification, it is uncertain whether
this is peculiar at all to the species. Articulations 4 to 6 times as long
as broad, at first filled with a yellowish green sporaceous mass, without
any marked pellucid border, with a single row in the centre of from 5 to
7 larger granules. The mass at length contracts, and the row of granules
is no longer visible. Short tubes are thrown out from the centre of the
joints, by which the filaments are at length connected into a more or less
intricate mass, and in the tubes a globular seed is formed, which swells
them, and is furnished with a pellucid border. In general the spora-
ceous matter of only one articulation passes into the tube to form the
seed ; nor in such case does the joint, of which the contents still appear
unaltered, throw out another tube. Found at Glapthorn, Northampton-
shire, in the spring of 1826, in watery spots of an exposed, ill-drained
field."

Plate XXIX. jig. 3- #> portion of sterile thread X 400 ; b,
threads in conjugation X 200; c, conjugating cells and zygospores of
Zygnema ordinarium, after Berkeley, magnification unknown.

B. Zygospores produced in one or other of the conjugating cells.
Zygnema cxuciatum. (Vauch.)

Sterile cells equal or twice as long as broad.

Zygospore sphserical, formed in one or other of two conjoined
cells. Membrane brown and scrobiculate.

SIZE. Cells -028 mm. broad. Zygospore '04 mm. diam.

Cleve Mon. Zygn. p. 29, t. 9, f. 1-3. Kirsch. Alg. Sehl. p.
126. Kutz. Tab. Phy. v. t. 17, f. 4.

Conjugata cruciata, Vauch. Hist. Conf. p. 76, t. 7, f. 2.

Tyndaridea cruciata, Hass. Alg. 160, t. 38, f. 1. Eng. Bot.
Ed. 2, t. 2512 B. Eng. Fl. v. p. 361. Mack. Hib. 231.

Conferva bipunctata, Dillw.Conf. t. 2. Hook Fl. Scot, ii, 81.

Zygnema bipunctatum, Johnst. Fl. Berw. ii, 256. Gray Arr.
i, 296.

Zygnema Dillwyni, Kutz. Tab. Phy. v. t. 17, f.

In ditches, pools, &c.

The form figured by Dillwyn is more slender than the typical form
and is considered by some as a distinct variety.

There is, perhaps, some difficulty in determining the exact limits of
the three species^, cruciatum, J5. stellinum, andJk Vaucherii, unless by
merging the latter two in one, and accepting Z. cruciatum as possessing
globose zygospores, whilst the other species has oval, or somewhat elon-
gated zygospores.

Plate XXX. fig. 1. a, portion of sterile thread X 400; b, conjugat-
ing threads with zygospores X 200 ; c, mature zygospore X 400.

80 ZYGOPHYCEJE.

Zygnema stellinum. (Vauch.} Kutz. Tab. V. t. 17, /. 2.

Sterile cells 1^ to 3 times longer than broad.

Zygospore broadly ovoid, formed in one or other of the con-
joined cells. Membrane brown, scrobiculate.

S poriferous cells commonly longer than the zygospore.

SIZE. Cells -022 mm. Zygospore '04 x '03 mm.

De Bary Conj. p. 78. Cleve Mon. Zyg. p. 28, t. 8, f. 9-11.
Rabh. Alg. Ear. iii, 249.

Conjugata stellina, Vauch. Conf. p. 75, t. 7, f. 1.

Thwaitesia Duricei, Mont. Fl. Alg. t. 15, f. 1.

Tyndaridea stellina, Jenner Fl. Tunb. Wells, p. 182.

In pools and ditches.

Kirschner unites this species and the next, for which he appears to
have great justification. We scarcely see how they can be maintained
as distinct if the broad view of Zygnema Vaucherii which we have
adopted is tenable.

No definite period can be fixed for the production of the zygospores,
not only in this species, but in the majority of the Zyynemacem. We
have observed them in June, or earlier, some as soon as April, and as
late as September. Hassall says " the species may be found in a state
of conjugation during the entire of the spring, summer, and autumnal
months ; they are chiefly met with, however, in this state in the
spring." Cleve has attached dates to the species enumerated by him,
but as these do not correspond with the periods at which we have found
them in this country, these dates are not quoted lest they should prove
misleading rather than useful.

Plate XXX. fig. 2. a, portion of sterile thread X 400 ; b, conjugat-
ing threads and zygospores X 400.

Zygnema Vaucherii. Ag. Syst. Alg. p. 77.

Sterile cells 2^- or 3 to 5 times as long as broad.

Zygospores subglobose or broadly elliptic, produced in one
or other of the conjugating cells, which is usually more or less
inflated, sporoderm delicately punctate.

SIZE. Cells '01-'022 mm. Zygospore, according to the
varieties.

Rabh. Alg. Eur. iii. 250.

Conjugata giacilis, Vauch. Conf. t. 6, f. 2.

Tyndaridea bicornis, Hass. Alg. 162, t. 38, f. 5.

Tyndaridea interposita, Hass. Ann. Nat. Hist. x. p. 43.

In ditches, ponds, &c.

var.a. tenue. Rabh. Alg. Ew. in. p. 250.
Sterile cells -019--022 mm., 1 to 3 times as long.

var. b. subtile. Rabh. Alg. Eur. in. ^?. 250.

Sterile cells -015--019 mm., 2 to 4 times as long.
Tyndaridea ovalist Hass. Alg. t. 38, f. 8.

ZYGNEMACE.E. 81

var. c. stagnale. Kirsch.

Sterile cells '01 mm., 3 to 4 times as long.
Tyndaridea stag?ialis, Hass. Alg. 162, t. 38, f. 9.
Tyndaridea stagnicola, Hass. Ann. N. Hist. x. (1842) p. 42.
Jenner Fl. Tunb. Wells, p. 182.

It will be seen from the above that this is a variable species, of which
two of the three varieties are British. These are by no means un-
common, often mixed with other filamentous algae, and can scarcely be
confounded with anything else, even when sterile.

Plate XXX. jig. 3. a, portion of sterile thread X 400 ; b, portion
of fertile thread with zygospores X 400. Fig. 4, var. subtile, a, portion
of sterile threads X 400 ; b, conjugating threads and zygospores X 400.
Fig. 5, rar. stagnale. a, portions of sterile threads X 400 ; b, fertile
cells with zygospores X 400.

Zygnema anomalum. (Hass.)

Sterile cells equal, or nearly twice as long as broad ; cytio-
derni thick, lamellose.

Zygospore globose, olivaceous (sporoderm distinctly punc-
tate ?).

SIZE. Cells -025 mm. diam., with mucous sheath about
double ; zygospore '026 mm. diam.

Tyndaridea lutescens, Hass. Alg. t. 38, f. 4. Dickie Bot.
Guide 296.

Tyndaridea cruciata, Harv. Man. p. 141.

Tyndaridea abbreviata, Hass. Ann. Nat. Hist. x. (1842) p. 43.

Tyndaridea anomala, Hass. Alg. t. 38, f. 2-3. Jenner Fl.
Tunb. Wells, 182. Ralfs, Eng. Bot. Supp. t. 2899.

In boggy pools.

The British species is the Tyndaridea anomala of Hassall and Kalfs,
and not the Zygnema anomalum of Continental botanists, which species
has the zygospore produced in the conjugating canal. The following is
the original description published by Ralfs in the supplement to " Eng-
lish Botany " :—

" It forms large, dark green masses in shallow pools on heaths. The
filaments are stout ; under the microscope each is found to be enclosed
in a hyaline sheath, which extends on each side about half the breadth
of the coloured portion, and is always more or less waved or scolloped.
At first it is nearly even, but it gradually becomes more and more irre-
gular, and the conjugating specimens are almost denuded. The joints
of the filament are usually about equal in length and breadth, but
sometimes twice as long as broad. The endochrome is blackish green,
and at first quadrate, when it completely fills the joint, but its division
into two portions gradually becomes apparent until two stellse, but less
distinct than those in the other species, are at last developed, when con-
jugation takes place in the usual manner. The spores, which are
globular, are contained in the joints of one of the connected filaments.
Not uufrequently the tubular processes are themselves converted into
cells containing endochrome.

" In its early state this plant is so different in appearance from the
other species, that at first sight its proper situation is scarcely appa-

82 ZYGOPHYCE.E.

rent. Indeed, having sent specimens to several celebrated algologists,
they hesitated to admit it into Tyndaridea, until Mr. Hassall, who also
at first strongly doubted whether it belonged to the Conjugate, fortu-
nately gathered fertile specimens. Such we ourselves found shortly
afterwards, and we have since repeatedly met with them ; the appear-
ance of the plant in conjugation, however, is so altered that its identity
can only be determined by tracing it through all its changes.

" In its usual state the sheath is very conspicuous, and the dense en-
dochrome so fills the cells that the plant looks like a Conferva, the con-
tinuity being interrupted merely at the dissepiments. When about to
conjugate the sheath has nearly or altogether disappeared, and the en-
dochrome is collected into two stellae, leaving the rest of the cell colour-
less."— Ralfs.

Hassall also found and examined the plant, and figured it with zygo-
spores in the cells of the filaments, whereas the Continental species,
since the figure by Kutzing, is always described as having the zygospore
in the canal of conjugation. There cannot, therefore, be the slightest
doubt that the species found by Hassall and Ralfs is quite distinct from
that known to Kutzing, Rabenhorst, and De Bary. Priority certainly is
in favour of Hassall's name, and it is the Continental species which must
give way, and yield up a name, acquired in error, to its rightful claimant.
Our figures are based on the sketches and drawings by Ralfs, with
whom we have been in communication on this question. It is absurd to
suppose that Ralfs and Hassall were both deceived, as well as Mr.
Jenner (an admirable observer), to whom the species was undoubtedly
known, and finally Mr. Salter in preparing the drawings from the
specimens for the " English Botany." Unfortunately we could find no
fruit in the specimens which we possess, collected by Ralfs forty years
ago, nor could we obtain specimens in conjugation from Cornwall during
the past spring.

Plate XXXI. fig. 1. a, b, portions of sterile threads X 400 ; c,
fertile cells with zygospores X 400, after Ralfs ; d, conjugating cells X
400.

Zygnema leiospermum. De Bary. Rabh. Algee Exs. No. 638.

Sterile cells equal in length and breadth, or sometimes twice
as long.

Zygospore globose or broadly oval, formed in one of two
conjugating cells ; membrane brown, even.

Sporiferous cells a little swollen.

SIZE. Cells -022 mm. (Ham. Zygospore '023-*03 mm.

De Bary Conj. p. 77, 1. 1, f. 7-14. Eabh. Alg. iii. 249. Kirsch.
Alg. Schl. p. 125.

In ditches filled after rain.

The two British species with the membrane of the zygospore even,
in this section, are the present and the following, which will require
some care in the discrimination. The inflated cells, which enclose the
zygospores, in the present, is relied upon as one of the featnres which
distinguish it from the succeeding ^species, as well as the larger size of
the zygospores.

Plate XXXI. Jig. 2. a, portion of fertile thread X 400; d, c,
fertile cells, with zygospores, after De Bary X 400 ; d, mature zygospore
X 400, after DeBary.

ZYGNEMACEJE. 83

Zygnema insigiie. Kutz. Tab. v. t. 17, /. 1.

Sterile cells equal, or twice as long as broad.

Copulation scalariforai or lateral ; zygospore globose or
slightly oval; membrane brown, even.

SJZE. Cells •026--03 mm. diam. ; zygospore about '026 x
•032 mm., or globose about '03 mm. diam.

De B;iry Conj. p. 78, t. 8, f. 14-16. Rabb. Alg. iii. 249.
Kutz. Tab. v. t. 17, f. 1. Kirsch. Alg. Schl. p. 125.

Tyndaridea insignis, Hass. Alg. p. 163, t. 38, f. 6, 7. Jenner
Fl. Tunb. Wells 182.

Zygnema tenue, Rabli. Exs. No. 674.

In streams and ditches.

The cells of this species at the time of conjugation are apt to become
much distorted, inflated sometimes on one side, sometimes on the other,
and even to conjugate in the manner represented by DeBary, and copied
on our plate,

Plate XXXI. frj. 3. a, sterile cells X 400; b, fertile cells with
zygospores X 200 ; c, fertile cells, with longitudinal conjugation, X 200,
after De Bary ; d, zygospore X 400.

GENUS 45. SPXROGYUA. Link. (1820.)

Cells with one to several parietal chlorophyll bands, usually
spirally winding to the right. Copulation ladder-like (Spiro-
gyrct) or lateral (Rhynchonema). Zygospores always within the
wall of one of the united cells. Copulating cells similar to the
sterile ones, or swollen out.

This genus, as now accepted, includes two genera as recognised by
Kutzing, Spirogyra and Mhynehonema. In the former the conjugation
was scalariform, and in the latter it was lateral. It is now found that
in many species, probably in all, both kinds of conjugation take place,
according to circumstances. The same filament, which in some portion
of its length conjugates with a neighbouring filament, has also been
observed conjugating laterally between two of its own cells. The genus
Rhynchonemot therefore has thus been proved to represent only one of
the modes of conjugation of the same plant, which under other condi-
tions conjugates with a neighbouring filament.

In past times too great importance was attached to the breadth and
length of the cells in the sterile filaments, and also to the character of the
spiral bands, features which are now known to be too variable to be relied
upon, the most important and reliable characters being derived from the
zygospore ; hence only specimens in fructification can be accurately
determined.

The most recent work on the species of Western Europe is a Mono-
graph of Spirogyra, as represented in France, by Mons. Paul Petit.
(Paris, 1880.) See also Professor Cleve's " Monograph of the Zygnemacese."

N

84 ZYGOFHYCE.E.

The following is a tabular arrangement of the British species : — •
Sec. 1. Cells not replicate at the ends.

A. Chlorophyll bands numerous (rarely two).

* Spores ovoid or elliptic.

f Membrane smooth.

1. crassa, Ktz.

2. jagalis, Dill.

3. nitida, Lie.

ff Membrane punctate.

None.
** Spores orbicular.

f Membrane smooth.

4. orthospira, Nag.

ff Membrane punctate.

5. orbicularis, Hass.

6. bellis, Hass.

B. Chlorophyll bands single or double (rarely ternate).

* Spore membrane smooth.

7. porticalis, Vauch.

var. a. quinina.

Chlorophyll bands usually single.
var. 0. decimina.

Chlorophyll bands usually binate, rarely ternate.
var. £. rivularis, Hass.

Chlorophyll bands usually three.
** Spore membrane punctate.

None.

"N.B. — Spirogyra elongata, Berk. Glean., p. 33, tab. 12, f. 3 (Rabh.
Alg. iii. 241), would follow here but that the fruit is unknown, and heuce
it is uncertain.

C. Chlorophyll bands single.

* Spore membrane smooth.

9. condensata, Vauch.
- 9. longata, Vauch.

10. flavescens, Cleve.

** Spore membrane punctate.
(N.B. — No record of Sp. velata or Sp. punctata in Britain.)

Sec. 2. Cells replicate at the ends.

A. Chlorophyll bands usually two or more,

* Spore membrane smooth.

11. Sp. insignis, Hass.
** Spore membrane punctate.

12. Sp. calospora, Cleve.

B. Chlorophyll bands single.

* Spore membrane smooth.

13. Sp. quadrata, Petit.

14. Sp. Weberi, Kutz.

15. Sp. tenuissima, Hass.

** Spore membrane punctate.

None.

ZYGNEMACE^E. 85

The English student may also consult with advantage a memoir " on
the germination of the resting spores in Spirogyra," by Dr. Pringsheim,
translated in the Annals of Natural History, 2nd ser., Vol. xi. (1853),
p. 210. "On the Structure and Division of the Vegetable Cell," by J.
M. Macfarlane, in Transactions of the Botanical Society of Edinburgh,
Vol. xiv. (1881). Pringsheim's Researches on Chlorophyll, translated by
Professor Bayley Balfour, in Quarterly Journal of Microscopical
Science, Vol. xxii., new series (1882). Darwin " On the Action of Car-
bonate of Ammonia on Chlorophyll Bodies," in Journal of the Linnean
Society, Vol. xix. (1882).

SECTION 1. Cells not replicate at the ends.
A. Chlorophyll hands numerous (rarely two].

Spirogyra crassa. Kutz.

Sterile cells with the extremities truncate, equal or twice as
long as broad. Chlorophyll bands four or more, making -I-li
turns.

Zygospores broadly and obtusely oval, membrane even.

Sporiferous cells persistent, not swollen.

SIZE. Cells -12--15 mm. diarn. (Rahh.), '15 mm. diam.
(Petit), zygospore -14--15 diam. (Petit), '13 x '12 ; -14 x '12 ;
•16 x '12 mm. (M.C.C.).

Zyguema serratum, Hass Alg. t. 18, f. 1.

Spirogyra crassa, Kutz. Tab. v. t. 28, f. 2 ; Kutz. Phy. Gen.
t. 14, f. 4 ; Kirsch. Alg. Schl. p. 119 ; Petit Spirogyra p. 32,
1. 12, f.-3, 4.

Spirogyra Heeriana, Kutz. Tab. v. t. 28, f. 3.

In ponds, &c. Fruiting in summer.

Hassall says of his Z. serratvm that the " filaments are of nearly the
same diameter as those of Z. orbiculare, but less mucous, from which
species it may readily be distinguished by the fewer number and ser-
rated appearance of the spores, the larger size of the granules, and the
form of the sporangia, which in Z. orbicidare are nearly sphserical, and
compressed, while in Z. serratum they are broadly ovate."

The sterile cells have a greater diameter than any other British
species, whilst their length varies from about half a diameter to two
diameters. The zygospore is comparatively broader than in S. jugalis,
and slightly flattened, so that when seen in certain positions it appears
to be narrower than it is, and more resembling that of S. jugalis.

On plate 32, figs. 1 and 2, the nucleus is represented in the centre of
the cells. Pringsheim has recently remarked, as a fact hitherto unre-
cognised, that " the threads of the protoplasm extending outwards from
the central plasma mass in each cell, do not, as was supposed, end in the
general protoplasmic lining of the cell wall, but each passes directly or
by its branches to the internal surface of a chlorophyll band, and there
dilates in a trumpet-like manner, and grasps, as it were, an amylum
body." — Researches on Chlorophyll, p. 81.

Plate XXXII. fig. 1. a, sterile cells X 200 ; b, fertile cells with
zygospores X 200 ; c, fertile cells of Bhynchonema form with zygo-
spore X 200 ; d, outline of zygospore X 400.

86 ZYGOPHYCEJ:.

Spirogyra jugalis. (Dill.)

Sterile cells with the ends truncate, and commonly equal, or
double the length of the diameter. Chlorophyll bands 4 to 5,
making 1 to 2 turns.

Zygospore elliptical, membrane even.

Sporiferous cells not swollen.

SIZE. Sterile cells -09--1 mm. diam. (Petit), '14 mm. diam.
(Cleve), '075--1 mm. diam. (Rabh.), 'OST-'ll mm. diam.
(Kirsch.). Zygospores -14 x 'I-'IZ mm. (Cleve), -15 x *1
mm. (Petit), -13--14 X -085--09 mm. (M.C.C.).

Conferva jugalis, Dillw. Brit Conf. t. 5.

Spirogyra jugalis, Kutz. Tab. v. t. 27, f. 2 ; Petit Spirogyra
p. 29, t/1 1, f. 3, 4 ; Rabh. Alg. Eur. iii. 245.

Spirogyra setiformis, Petit Spirogyra, p. 29, t. 11, f. 1, 2
(not Kutz., nor Rabh. Alg. Eur.): Rabh. Exs. 2292 ; Cleve
Mon. Zyg. p. 15 (partly), t. 1, f. 1-3.

In clear ponds, &c. Fruiting at Midsummer.

The British specimens which we refer to this species have the sterile
cells from '12 to '14 mm. broad, and about two diameters long. The
zygospore is from '13 to '14 mm. long and '085 mm. broad. In other
specimens, from the Continent, we have found the zygospores from '11
to '13 mm. long and '095 mm. broad. M. Petit recognises two species,
which he calls respectively S. jugalis and S. setiformis, differing so little
from each other that it seems scarcely possible to distinguish them except
in extreme cases. To the latter he refers Z. interruptum of Hassall,
but, without the fruit, which Hassall never found, it is difficult to affirm
what it might be. It is quite as probable that it was S. orbicularis as
anything else.

Plate XXXII. fig. 2. a, sterile cells X 200; ?>, fertile cells with
zygospores X 200; c, outline of zygospore X 400.

Spirogyra nitida. (Dillw.) Link Handbk. in., 262.

Sterile cells with the ends truncate, and usually 2 to 4 times
as long as broad ; chlorophyll bands about 4, making 1 to 4
turns of the spiral.

Spores elliptic ovoid (almost almond-shaped), 1-| times as
long as broad, membrane even.

Sporiferous cells persistent.

Germinating plant clavate, radical cell much attenuated.

SIZE. Herile cells -072--07S mm. diam. (Petit), '08-09
mm. (Clerc), -06--075 mm. (Rabh.), '054--077 mm. (Kirsch},
•07--09 mm. (M.C.C.). Zygospore -1 x ' 07 2 mm. (Cleve), '11-
•13 X -06--07 mm. (M.C.C.).

Spirogyra princeps, Cleve Monog. Zygn. p. 16, t. 1, f. 4 to 7.

Conjugata princeps, Vauch. Conf. p. 64, t. 4, f. 1.

Zygneina nitidum, Lyngb. Tent. Hydr. t. 59, f. B. Hass.
Alg. t. 22. Harv. Man. p. 143. Eng. Fl. v. 362. Eng. Bot.
Ed. ii. t. 2509. Mack. Fl. Hib. 231. Hook. Fl. Scot. ii. 80.
Dickie Bot. Guide 296.

ZYGNEMACE.E. 87

Spirogyra nitida^ Kutz. Tab. Phy. v. t. 27, f. 1. Kirscli.
Alg. Schl. p. 123. Petit Spirogyra p. 28, t. 10, f. 6 to 10.

Conferva nitidum, Dill. Conf. t. 4, f. C. Eng. Bot. ed. i. t.
2337. Jermer Fl. Tunb. Wells 178. Gray Arr. i. 298.

Zygnema rostratum, Hass. Alg. t. 33, f. 1.

In ponds, &c.

Very little requires to be said of this species, which is the most
common one with thick filaments in Britain. It is most probable that
HassalFs Zyynema rostratum is the same, conjugating longitudinally, for
he says that the filaments are somewhat larger than those of his
Zygnema nitidum, but that he had only seen it once, The form of
zygospore figured by him is that of the present species, and not of
Spirogyra bellis, to which the Rhynchonema rostrata of Kutzing is re-
ferred by Cleve.

Cleve proposed to substitute the name of Spirogyra princeps, Vauch.,
for the universally known Spirogyra nitida, a change with which we by no
means sympathise, because, after all, it is only a matter of opinion, and
not of demonstration, whether this is really the Conjugata princeps of
Vaucher, and there should be a good and substantial reasons for super-
seding a specific name so long recognised as Spirogyra nitida.

Plate XXXIII. Jig. I. a, b, sterile cells X 200 ; c, conjugating cells
with zygospores X 200 ; d, outline of zygospore X 400.

Spirogyra oxthospira. Nag. in Kutz. Spec. p. 441.

Sterile cells with the extremities truncate, and from 2-| to 4
to 10 times as long as broad ; chlorophyll bands 3 to 4 to 5
(rarely 7), sometimes erect, sometimes forming a very lax
spiral.

Spores orbicular, flattened, membrane even.

Sporiferous cells scarcely swollen, 2-| to 4 times as long as
the diameter.

SIZE. Cells *05-*065 mm. diam. ; zygospore '07 mm. diam.,
•048 mm. thick.

Spirogyra orthospira, Archer in Quart. Journ. Micr. Sci.,
1870. Petit Spirogyra p. 30, t. 10, f. 4, 5.

Spirogyra majuscula, Kutz. Tab. Phy. v. t. 26, f. 1. Rabh.
Alg. iii. 244.

In pools. Fruiting in autumn.

This is a recently discovered species in the British Islands, and has
hitherto only been recognised by Mr. Archer in Ireland.

Plate XXXIII. Jig. 2. a, a, sterile cells X 200 ; b, conjugating
cells with zygospores X 200 ; c, front and side views of zygospore X
400.

Spixogyxa oxbiculaxis. Hassa.ll Alg. t. 19.

Sterile cells with the ends truncate, about equal in length to
breadth; chlorophyll bands 5 to 7, making -^ to 1 turn.
Zygospores orbicular, flattened, membrane punctate.
Sporiferous cells not inflated.

88 ZYGOPHYCE.E.

SIZE. Cells '11--14 mrn. diam. ; zygospores '1 mm. diam.
Narrow diameter '08 mm.

Petit Spirogyra p. 31, t. 12, f. 1, 2. Kutz. Tab. v. t. 27, f.
3. Kirsch. Alg. Schl. p. 118. Rabh. Alg. Eur. iii. 245.

Zygnema orbiculare, Hass. Alg. p. 138, t. 19. Jenner Fl.
Tunb. Wells 178.

Zygnema alternatum, Hass. Alg. 139, t. 20.

Zygnema interruptum, Hass. Alg. 140, t. 21. Ann. Nat.
Hist. 1843, p. 432.

Zygnema maximum, Hass. Ann. Nat. Hist. x. (1842), p. 36.

Spirogyra alternata, Kutz. Spec. 442. Rabh. Alg. iii. 248.

Spirogyra setifonnis, Kutz. Tab. v. t. 28, fig. 1 (not Petit).
Rabh. Alg. iii. 246. Cleve Mon. Zyg. p. 15 (in part).

In ponds, &c. Fruiting in autumn.

There is nothing inconsistent in Cleve's suggestion that Hassall's
three plates 19, 20, and 21 all belong to the same species. No reliance
can be placed on the width of the chlorophyll bands, nor the little
difference in the breadth of the cells. Of course the disturbance in the
bands of the conjugated cells is due to the conjugation. When this
species is really in fruit there can be no difficulty in its determination,
and, without fruit, it is folly to waste time in attempting to guess at the
relationship of any species.

Hassall says that " it is found in ponds and dykes whose waters are
deep and permanent, and it does not conjugate until near the end of
summer." " Cells when in a state of conjugation, a little longer than
broad, prior to which, however, they are frequently not half so long as
broad ; winding round the interior of these are about eight spiral
threads, the granules in them being small."

Plate XXXIV. fig. 1. «, sterile cells X 200 ; b, conjugating cells with
zygospores X 200 ; c, outline of zygospore X 400.

Spirogyra bellis. Hassall.

Sterile cells with the ends truncate, and usually 1^ times
(rarely 3 times) as long as broad ; chlorophyll bands 5 to 6,
making -^ to 1 turn, or nearly erect.

Spores orbicular, depressed, with the membrane punctate or
porose, chestnut colour.

Sporiferous cells persistent, swollen.

Germinating plant cylindrical, radical cell short and sub-
cylindrical.

SIZE. Cells •07-'08 mm. ; zygospore *07-'OS mm. diam.,
•05-'06 mm. thick.

Cleve Monoor. Zygn. p. 18, t. 3, f. 2 to 5. Petit Spir. p.
31, t. 10, f. 1 to 3.

Zyqnema beUa, Hass. Alg. p. 142, t. 24. Ann. Nat. Hist,
x. (1842), p. 37. Jenner Fl. Tunb. Wells 178.

Spirogyra subcequa, Kutz. Tab. Phy. v. t. 26, f. 2.

Rhynchonema ro stratum, Kutz. Tab. Phy. v. t. 34, f. 3. (Not
Zygnema rostratwn, Hass. Alg. t. 33, f. 1.)

ZYGNEMACEJS. 89

Zygnema neglectum, Hass. Alg. t. 23, f. 1 (not Petit). Hass.
Ann. Nat. Hist. x. 37. Jenner Fl. Tunb. Wells 178.

In ponds. Fruiting in August.

This species is rather a characteristic one, of which it appears to us
that Zygnema neglectum, Hass., is only a form with three chlorophyll
bands. If the two species of Hassall are drawn to the same scale, it is *
difficult to indicate any specific difference. The Rhynchonema rostratum
of Kntziiig is referred by Cleve to this species, but the Zygnema
rostratum of Hassall appears to be different, with thicker filaments and
much longer zygospores, and is rather referable to Spvrogyra nitida.
The Spirogyra neglecta of Petit cannot be the Zygnema neglectum of
Hassall.

This species is thus described by Hassall : — " Filaments about a foot
in length, with truncate extremities ; of considerable though rather less
diameter than those of S. nitida, mucous, glossy, and of a deep and
beautiful green colour ; investing membrane of the cells very evident
and transparent. Cells in the young filaments scarcely so long as broad,
but their length exceeds their breadth in those which have conjugated ;
round the interior of the cells five or six loose spiral tubes may be
faintly discerned ; these contain the reproductive globules (sic;), which
are large and distinct, with a dark central nucleus. Sporangia oval
sometimes almost circular and flattened, lying in inflated cells, the
cavity of which they do not fill."

Plate XXXIV. fig. 2. a, sterile cells X 200; b, conjugating cells with
zygospores X 200 ; c, fertile cells of Rhynchonema form with zygospore
X 200 ; d, outline of zygospore X 400.

B. Chlorophyll bands single or double (rarely ternate).
Spixogyra porticalis. Vauch.

Sterile cells with the extremities truncate, 2 to 4 times
longer than the diameter ; chlorophyll bands single, or binate,
rarely ternate.

Spores obtuse, ovoid, 1^ times longer than the diameter,
membrane even, chestnut colour.

Sporiferous cells equal to the length of the spore, or twice as
long, more or less turgid.

SIZE. Cells -032--05 mm. diam. Zygospore -08 X O48--05
mm.

Cleve Monog. Zygn. p. 22, t. 5, f. 8 to 13.

Conjugata porticalis, Vauch. Conf. p. 66, t. 5, f. 1.

In ditches, &c. Fruiting in spring.

a. quiniiia.

Chlorophyll bands usually single.

SIZE. Cells -035--045 mm., about twice as long.

Zygnema quinmum, Hass. Alg. t. 28, f. 1, 2. Harv. Man. p.
143. Landsborough Brit. Seaweeds p. 362. Eng. Fl. v. 362.
Eng. Bot. Ed. ii. p. 175. Harv. Man. 143. Johnst. Fl. Berw.
ii. 256. Grev. Fl. Ed. 320. Mac. Fl. Hib. 231. Fl. Devon
ii. 50. Hook. Fl. Scot. ii. 80. Dickie Bot. Guide, 296.

90 ZYGOPHYCE.E.

Spirogyra quinina, Kutz. Tab. v. t. 22, f. 2.

Spirogyra porticalis, Petit iSpirogyra, p. 21, t. 5, f. 8-12.

Conferva spiralis, Dillw. Conf. t. 3. Eng. Bot. Ed. i. t. 1656.

Zygnema spiralis, Eng. Bot. Ed. ii. t. 2561.

Conjugata quinina, Gray Arr. i. 297.

var. (3. decimina.

Chlorophyll bands usually 2, sometimes 3.

SIZE. Cells -034--04 mm., 2 to 4 times as long.

Zygnema deciminum, Hass. Alg. t. 23, f. 3, 4. Harv. Man.
p. 143. Johnst. Fl. Berw. ii. 255. Mack. Fl. Hib. 2, 31. Fl.
Devon ii. 50. Jenner Fl. Tunb. Wells 178. Grev. Fl. Edin.
320. Eng. Fl. v. 362.

Spirogyra decimina, Kutz. tab. v. t. 23, f. 3, 24, f. 1. Petit
Spirogyra p. 25, t. 8, f. 1-3. Rabh. Alg. iii. p. 242.

Spirogyra flavicans, Kutz. tab. v. t. 23, f. 3.

Spirogyra laxa, Kutz. Tab. v. t. 23, f. 3.

Spirogyra major, Kutz. Tab. v. t. 24, f. 2.

Conferva jugalis, Dillw. Conf. t. 5.

Conferva inflata, Eng. Bot. Ed. i. t. 2376.

Zygnema injlatum, Eng. Bot. Ed. ii. t. 2510. Hook. Fl.
Scot. ii. 80.

Conjugata inflata, Gray Arr. i. 297. (?)

Conjugata decimina, Gray Arr. i. 299.

var. c. rivulaiis. Hass.

SIZE. Cells "032--036 mm., 5 to 10 times as long.
Zygnema rivulare, Hass. Alg. 144, t. 27, f. 1, 2. Annals
Nat. Hist. x. 38.

Spirogyra rivularis, Rabh. Alg. Eur. iii. 243.

Undoubtedly if the nterile threads of this species are carefully ex-
amined, they will furnish abundant evidence that the number of spiral
bands is variable, for cells will constantly be found in the same filament
in which either one or two bands occur. So that, with the great simi-
larity in fruit, it would be folly to think of maintaining the two varieties
decimina and quinina as distinct species, on account of the number of
chlorophyll bands. The Z. rivulare of Has sail, which we have included
as a third variety, is not uncommonly found in a sterile condition, in so
far as it can be determined in this stage, but hitherto we have not seen
it in fruit. It is said to be found on the Continent in fructification, but
we have no knowledge of the Continental form. The spirals in the
sterile cells are usually three, and then very nearly identical with the
condition of the variety decimina, in which the bands are the same in
number,

Plate XXXV. fig. ], form quinina. a, sterile cells X 200; b, c, conju-
gating cells with zygospores X 200 ; d, outline zygospores X 400. Fig. 2,
form decimina. a, sterile cells X 200 ; b, conjugating cells with zygo-
spores X 200 ; d, outline zygospore X 400. Fig. 3, form rivularis. a,
sterile cells X 200.

ZYGNEMACE^E. 91

C. Chlorophyll bands single.
Spirogyra condensata. Vauch.

Sterile cells with the extremities truncate, and commonly
1 to 3^ longer than the diameter. Chlorophyll bands single,
rarely two, making 1^- to 2 turns of the spiral.

Spores broadly obtuse, ovoid, or subspherical, membrane even,
chestnut colour.

Sporiferous cells turgid, and usually shorter than the spores.

SIZE. Cells '04 mm. diam., zygospores *035-*04 mm. diam.

Cleve Monog. Zygn. p. 21, t. v. f. 1-7.

Conjugata condensata, Vauch. Conf. t. 5, f. 2. Gray Arr.
i. 298.

Zygnema rarians, Hass. Alg. t. 29, f. 3 and 4. Jenner
Fl. Tunb. Wells, 180.

Zygnema Woodsii, Hass. Alg. t. 33, f. 2. Jenner Fl. Tunb.
Wells, 180.

'Spirogyra torulosa, Kutz. Tab. v. t. 20, f. 2.

Spirogyra nodosa, Kutz. Tab. v. t. 20, f. 3.

Spirogyra arcta, Kutz. Tab. v. t. 21, f. 2.

Spirogyra condensata, Kutz. Tab. v. t. 22, f. 3. Petit Spiro-
gyra, p. 22, t. 9, fig. 6-8.

Rhynchonema Woodsii, Kutz. Tab. v. t. 34, f. 2 (not of Nord.
and Wittr. Exs., No. 7«9).

Spirogyra Flechsigii, Rabh. Hedw. i. p. 4G.

Zygnema quininum, var. Hass. Ann. Nat. Hist. x. (1842) 35.

Spirogyra ulotrichoides, Kutz. Tab. v. t. 21,f. 3.

Spirogyra varians, Kutz. Sp. Alg. p. 439. Petit Spirogyra
p. 49, t. 4, f. 1-8.

Spirogyra injiata, Kutz. Tab. v. t. 21, f. 1-8.

In pools. Fruiting in spring.

From the number of synonyms quoted above, it may be inferred that
this is a variable species. All the forms seem to be included by Petit
under his Spirogyra condensata and S. varians.

Hassall thus alludes to a peculiar nodoluse growth of some of the
forms : — " When a number of cells unite in regular order with those of a
neighbouring filament, no inflation of any of these occurs ; but it fre-
quently happens that several adjoining cells of a filament for some reason
or other do not unite, although the remaining ones in that filament do,
in which case those which have not yoked themselves swell up, assuming
a monoliform appearance, and at the same time frequently emit blind and
irregular processes or prolongations, by which the cells manifest the
strong tendency which they have to conjoin themselves, but which some
cause, not evident, would appear to have frustrated. In some speci-
mens the number of inflated cells and blind processes is but smali,
while in others the elongated cells are more numerous than those which
have united in the ordinary manner." A similar circumstance may
sometimes be observed in S. longata, especially in the short-celled
forms.

O

92 ZYGOPHYCEiE.

Plate XXXVI. fig. 1. a, sterile cells X 200 ; 5, conjugating cells with
zygospores X 200 ; c, sterile cells of inflated form X 200 ; d, conjugating
cells with zygospores X 200; e, f, g, outlines of zygospores X 400.

Spirogyra longata. Vauch.

Sterile cells with the ends truncate, 3 to 8 times as long as
broad, chlorophyll bands single or rarely two, making 1± to
6 turns of a spiral.

Spores 1^ to 2 times as long as broad, membrane even, chest-
nut colour.

S poriferous cells swollen and usually longer than the spore.

SIZE. Cells -024--03 mm. diarn. Zygospore -04--07 x '03 mm.

Cleve Monog. Zygn. p. 20, t. 3, f. 8-10; t. 4, f. 1-7 ; t. 10,
f. 11-13.

Conjugata longata, Vauch. Conf. p. 71, t. 6, f. 1.

In pools and ditches.

far. a. c omniums.

Sterile cells 3 to 8 times as long as broad.

Spirogyra longata, Kutz. Tab. v. t. 20, f. 1. Rabh. iii. 238.
Petit Spirogyra t. 5, f. 4, 5.

Zygnema commune, Hass. Alg. t. 28, f. 5, 6. Ann. Nat. Hist,
x. (1842) p. 39. Jenner Fl. Tunb. Wells, 180.

Zygnema (Estivum, Hass. Alg. t. 28, f. 3, 4. Ann. Nat. Hist,
xi. (1843), p. 433. Jenner Fl. Tunb. Wells, 180.

Zygnema angulare, Hass. Alg. t. 34, f. 1, 2. Jenner Fl.
Tunb. Wells, 180.

Zygnema angidatum, Hass. Ann. Nat. Hist. x. (1842) p. 41,

Zygnema reversum, Hass. Alg. t. 33, f. 3.

Zygnema alternatum, Hass. Alg. p. 154.

Zygnema mirabile, Hass. Alg. t. 35, f. 1-3.

Spirogyra communis, Kutz. Tab. v. t. 19, f. 4. Petit Spiro-
gyra t. v. f. 1-3.

Rhynchonema angulare, Kutz. Tab. v. t. 34, f. 1. Rabh. iii.
232. l

Rliynclwnema reversum, Kutz. Rabh. iii. 232.

Spirogyra subtilis, Kutz. Tab. v. t. 19, f. 5.

Spirogyra mirabilis, Kutz Sp. p. 438. Petit Spirogyra p. 14,
t. 3, f. 3-4.

Conjugata longata, Gray Arr. i. 279 (?)

var. (3. turpis.

Sterile cells abbreviated.

Zygnema malformatum, Hass. Alg. t. 30, f. 1, 2. Ann. Nat.
Hist. x. (1842) p. 39. Jenner Fl. Tunb. Wells, 180.

Zygnema catceneforme, Hass. Alg. t. 30, f. 3, 4. Ann. Nat.
Hist. x. (1842), p. 39.

Zygnema abbreviatum, Hass. Alg. t. 34, f. 4.

ZYGNEMACEJ2. 93

Spirogyra turpis, Kutz. Tab. v. t. 19, f. 2. Rab. iii. 238.
Spirogyra catceneformis, Kutz. Tab. v. t. 19, f. 1. Rab. iii.
238. Petit Spirogyra t. 3, f. 9-12.

Rhynchonema abbrevialum, Kutz. Rab. iii. 248.

We venture to differ from onr friend Mons. Petit in uniting four of his
species. Iu fact, if four species are to be accepted, we see no logical
grounds for refusing to accept a dozen, because of the excessive vari-
ability in the sterile cells.

Plate XXXVI. Jic/, 2. a, b, sterile cells X 200; c, conjugating cells

with zygospores X 200; d, fertile cells of RJiynchonema form with zygo-

spore X 200 ; e, fertile cells of mirabilis form with zygospores X 200 ;

f, conjugating cells of catenceformis form with zygospores X 200 ; gt Ji, it If,

outline zygospores X 400.

Spirogyra flavescens. (HassJ Cleve.

Sterile cells with the ends truncate, 2£ to 5 times longer than
broad, chlorophyll bands single.

Spores attenuated, twice as long as broad, membrane even,
chestnut colour.

Sporiferous cells swollen, and usually longer than the spores.

SIZE. Cells '02 mm. diam. Zygospore -05 X '024 mm.

Cleve Monog. Zygn. p. 19, t. 3, f. 6, 7.

Boggy pools on heaths, &c.

form a. gracilis.

Zygospore about '03 mm. diam.
Zygnema gracile, Hass. Alg. t. 30, f. 5, 6.
Spirogyra gracilis, Kutz. Tab. v. t. 18, f. 5. Petit Spiro-
gyra p. 15, t. 3,f. 7, 8.

Zygnema malleolum, Hass. Alg. t. 34, f. 5.
RJiynchonema malleolus, Kutz. Tab. v. t. 33, f. 3.

form b. flavescens.

Zygospore about '02 mm. diam.

Zygnema Jlavescens, Hass. Alg. t. 30, f. 9, 10. Jenner Fl.
Tunb. Wells, 180.

Spirogyra Jlavescens, Kutz. Tab. v. t. 18, f. 4. Petit Spiro-
gyra p. 15, t. 3, f. 5, 6.

Zygnema affine, Hass. Alg. t. 34, f. 6.

Spirogyra affinis, Petit fcpirogyra, p. 18, t. 3, f. 12, 13.

RJiynchonema affine, Kutz. Tab. v. t. 33, f. 2.

form c. parva.

Zygospore about '01 mm. diam.

Zygnema parvum, Hass. Alg. t. 30, f, 7, 8. Ann. Nat. Hist,
x. (1842) p. 41. Jenner Fl. Tunb, Wells, 180.
Spirogyra parva, Kutz. Tab. v. t. 18, f. 3.

This species includes five of Hassall's species of Zygnema, which sub-
sequently were relegated by Ktitzing, three to Spirogyra and two to
Ehynchon&ma. The Zygnema Jlavescens, parvum, and gracile, are sepa-

94 ZYGOI-HYCE.E.

rated by distinctions so minute and variable, that they cannot be main-
tained as other than varieties, and Zyynema mcilleolwn and Z. affine were
at the time suspected of being varieties the one of the other.

Plate XXXVII. fig, 1. Variety gracilis. a, sterile cells X 200 ; fc,
conjugating cells with zygospores X 200 ; c, fertile cells of Rhyncho-
nema form with zygospores X 200 ; d, ontliue zygospores X 400. Fig. 2,
variety flavescens. a, sterile cells X 200 ; b, c, conjugating cells with
zygospores X 200; d, fertile cells of Rlninclionema form with zygospores
X 200 ; e, outline zygospores X 400. Fig. 3. variety parva. a, sterile
cells x 200 ; b, conjugating cells with zygospores X 200 ; c, outline
zygospores X 400.

SECTION 2. Cells replicate at tlieends.

A. Chlorophyll bands usually two or more.
Spirogyra insignis. Hass.

Sterile cells with the extremities replicate, 41 to 5 (rarely 6)
times as long as broad, chlorophyll bands 2 to 3, lax, with 1 to 2
turns of spiral, or nearly erect.

Spores ovate-elliptic, twice as long as broad, membrane even/

Sporiferovts cells slightly swollen.

SIZE. Sterile cells -03--035 mm. Zygospore '04--05 mm.,
2 to 3 times as long.

Rabh. Alg. Eur. iii. 243.

Zygnema insigne, Hass. Alg. 440, t. 103, f. 1,2.

ZygnemaHassallii, Hass. Alg. 157, t. 36, f. 4,5. Jenner Fl.
Tunb. Wells, 182.

Spirogyra insignis, Kutz. Tab. v. t. 31, f. 4. Sur. Obs.
t. 1, f. a.

Rhynchonema HassaUii, Kutz. Tab. v. t. 32, f. 7.

Spirogyra Braunii, Rabh. Alg. Ex. No. 1310, 1395.

Spirogyra Hantschii, Eabh. Alg. Ex. No. 1291.

Spirogyra Theobaldii, Kutz. Tab. v. t. 31, f. 2.

Spirogyra Hassallii, Petit Bull. Soc. Bot. Fr.; Spirogyra t. 2,
f. 6-8.

Rhynchonema gallicum, Ripart. in Petit Spirogyra.

In streams.

The number of British species in which the cells have replicate ends
is much less than of those with truncate ends. We have only included
two species with two or more chlorophyll bands, in one of which the
membrane of the zygospore is smooth, and in the other punctate. Doubt-
less neither of them are common.

Plate XXXVIII. jig. 1. o, c?, sterile cells X 200 ; &, conjugating cells
with zygospores X '200 ; c, fertile cells of Rhynchonema form X 200;
outline zj-gospore X 400.

Spirogyra calospora. Cleve Jfon. Zyg. p. 26, t. 8,/. 1-5.

Sterile cells with the extremities replicate, 6 to 12 times as long
as broad, chlorophyll bands 1 to 3, making 2£ to 7 turns.

Spores elongate, obtuse ovoid, 1 J to 2 times as long as broad,
membrnne yellow, screbiculate.

Sporiferous cells scarcely turgid.

ZVGNKMACE^E. 95

form a major.
Diameter of threads '05 mm. Bands 2 to 3.

form (3 minor,

Diameter of threads -032 mm. Band single.
SIZE. Zygospore -078--096 x -045 mm.

Archer in Quart. Journ. Micr. Sci., 1873, xiii. p. 436. Petit
Spirogyra p. 11, t. 2, fig. 11-13.

Spirogyra protecta, Wood. F. W. Alg. t. 14, f. 3.

In bogs and moor pools.

Plate XXXVIII, Jig. 2. a, sterile cells X 200 ; b, c, conjugating cells
with zygospores X 200 ; d, outline zygospore X 400.

B. Chlorophyll bands single.
Spirogyra quadrat a. (Hass.) Petit.

Sterile cells 3 to 9 times aslong as broad. Fertile cells turgid,
quadrate. Zygospore elliptical. Sporoderm brown.

SIZE. Cells -024 to -027 mm. Zygospore •042--Q48 mm.
diam., 1* to 2 times as long.

Petit Spirogyra p. 8, t. 1, fig. 13. Bull. Soc. Bot. France
xxi. p. 14, t. 1, fig. 2.

Zygnema quadratum, Hass. Alg. 157, t. 37, f. 1, 2. Jenner
Fl. Tunb. Wells, 182.

Rhynclionema quadrata, Kutz. Tab. Phy. v. t. 32, f. 6.

In pools.

We have accepted Petit's diagnosis of this species, which Hassall had
seen only with the Rhynchonema mode of conjugation, but which has
now been ascertained to conjugate in both ways. His description is very
short for a species which he says is "by no means uncommon," and he
evidently depends as a specific feature on the quadrangular enlarge-
ments of the fertile cells. " Cells usually seven or eight times as long as
broad. Sporangia oval, large, and much elongated, contained within
quadrangular enlargements of the cells."

Plate XXXIX. Jig. 1. a, fertile cells in conjugation with zygospore
X -;00, after Petit ; fe, zygospore in cell X 400.

Spirogyra Weberi. Kutz.

Sterile cells with the extremities replicate, 7 to 12 times as
long as the diameter, chlorophyll bands single, 3 to 8 turns of
the spiral.

Spores ovoid, scarce broader than the sterile threads, mem-
brane even, chestnut, twice as long as broad.

Sporiferous cells scarcely turgid.

SIZE. Spores : (a) -072 x -034 mm. (/3) -068 x '034 mm.

Cleve Monog. Zygn. p. 25, t. vii., f. 1-10.

form a. ineequalis.

Diameter of thread '03 mm. Sporiferous cells scarcely
longer than the spores.

Zygnema incequale, Hass. Alg. 150, t. 32, f. 1 to 2.

Zygnema intermedium, Hass. Alt>\ t. 37, f. 3. Ann. Nat.
Hist. x. (1842) p. 41. Jenner Fl. Tunb. Wells, 182.

96 ZYGOrHYCEJ3.

Spirogyra incequalis, Kutz. Tab. v. t. 30, f. 3.
Zygnema Grevilleanum, Hass. Alg. 149, t. 31, f. 1,2. Hass.
Ann/ Nat. Hist. x. 38. Jenner Fl. Tunb. Wells, 180.

form b. subventxicosum.

Sporiferous cells 2 to 4 longer than the spores. Diam. '026 mm.
Spirogyra Weberi, Rabh. Alg. Eur. iii. 233.
Zygnema sub-ventricosum, Hass. Alg. 150, t. 32, f. 4, 5. Jenner
Fl. Tunb. Wells, 180.

Zygnema diductum, Hass. Alg. t. 37, f. 4.

Rhynchonema diductum, Kutz. Tab. v. t. 32, f. 3.

Spirogyra ventricosa, Kutz. Tab. v. t. 29, f. 5.

Zygnema ventricosum, Hass. Ann. Nat. Hist. x. (1842) p. 38.

Zygnema longatum, Hass. Alg. 151, t. 31, f. 3, 4.

In ditches. Fruiting in summer.

The absence of any measurements, or uniformity in magnification in
the figures, renders it very difficult to determine many of Hassall's
species with any certainty. From present information we are unable to
recognise Z. Grevllleanum as a distinct species.

Plate XXXIX. Jig. 2. a, sterile cells X 200 ; b, c, conjugating cells
with zygospores X -00 ; d, fertile cells of Rhynchonema form with
zygospores X 200.

Spirogyra tenuissixna. Hass.

Sterile cells with the extremities replicate, 5 to 15 times as
long as the diameter. Chlorophyll bands single, making 3 to 6
turns of the spiral.

Spores broader than the sterile cells, elongated ovoid, twice
as long as the diameter, membrane even and chestnut colour.

Sporiferous cells turgid.

SIZE. Spore '055 (a)--058 (0) x '024 (a)--03 mm. (/3).

Cleve Monog. Zygn. p. 24, t. 6, f. 5-7.

form a. tenuissixna.

Sterile cells 8 to 16 times as long as broad. -012--015 mm.
diam.

Sporiferous cells 2 to 3 times as long as the spores.

Zygnema tenuissimum, Hass. Alg. t. 32, f. 9, 10. Ann. Nat.
Hist. x. (1842) p. 41. Jenner Fl. Tonb. W., 180.

Zygnema minimum, Hass. Alg. t. 37, f. 8.

Spirogyra tenuissima, Kutz. Tab. v. t. 29, f. 2. Rabh. Alg.
Eur. iii. 233.

Rhynchonema minimum, Kutz. Tab. v. t. 33, f. 1.

Spirogyra Naegelii, Kutz. Tab. v. t. 29, f. 3.

form b. inflata.

Sterile cells .5 to 10 times as long as broad. *017-*02 mm.
diam.

Sporiferous cells scarcely longer than the spores.

ZYGNEMACE^E. 97

Zygnema varians, Hass. Ann. Nat. Hist. xi. (1843) p. 431.
Conjugata inflata, Vauch. Conf. p. 68, t. 5, f. 3.
Zygnema inflatum, Hass. Alg. t. 32, f. 6, 7. Jenner Fl. Tunb.
Wells, 180.

Zygnema Jenneri, Hass. Alg. t. 37, f. 6. Jenner Fl. Tunb.

Wells, 182.

Zygnema dubium, Hass. Alg. t. 37, f. 7.
Spirogyra gastroides, Kutz. Tab. v. t. 29, f. 4.
Rliynchonema Jenneri, Kutz. Tab. v. t. 32, f. 1.
Rhynchonema dubium, Kutz. Tab. v. t. 32, f. 2.
Spirogyra inflata, Rabh. Alg. Eur. iii. 233.

In pools.

This species includes the most delicate of British species with repli-
cate ends to the cells. In all the forms of both varieties there is an
evident tendency in the fertile cells to become more or less inflated. The
only difference which Hassall indicates between his Z. inflatnm and Z.
tenuissimum is one of size, which may be influenced by the circum-
stances of growth.

Plate XXXIX jig. 3. a, sterile cells X 200 ; b, conjugating cells of va-
riety a, with zygosporeaX 200; c, conjugating cells of variety b, with
zygospores X ^00 ; d, outline of zygospores X 400.

GENUS 46. SIROGONIUM Kutz. (1843.)

Cells with" parietal longitudinal chlorophyll bands. Fructi-
fying cells diverse, arising by unequal division of the thread-
cells, bending knee-like towards each other and growing
together, united at the point of adnation ; receiving-cells barrel-
shaped ; giving-cells short, cylindrical. Zygospore (elliptic) in
tbe receiving cell-wall.

The sterile cells, with parallel chlorophyll bands, resemble those of
Spirogyra, but differ in the genuflexuous conjugation.

Sirogonium sticticum. Kutz.

Sterile cells 2 to 5 times as long as broad.

Zygospore broadly elliptical, spore-coat double.

Sporiferous cells swollen, abbreviated.

SIZE. Cells -04 to '05 mm., 2 to 5 times as long. Zygospore
•042 x '075 mm.

De Bary Conj. p. 78, t. 2, figs. 1-6. Rabh. Alg. Eur. iii., 256.

Sirogonium breviarticulatum, Kutz. Tab. Phy. v. t. 4.

Sirogonium Braunii, Kutz. Tab. Phy. v. t. 4.

Conferva stictica, Eng. Bot. t. 2463.

Zygnema curvatum, Ag. Eng. Fl. v. 362. Harv. Man. p.
143. Eng. Bot. Ed. ii. t. 2512, f. A. Hassall Alg. 143, t. 26,
f. 1, 2.

Choaspes serpentina, Gray Arr. 1, 299.

In ponds and ditches and moor pools.

98 ZY«OPHYCE,E.

" It forms large masses on the water, full of air-bubbles, being pale
and yellowish above, and of a blackish green beneath. Filaments not
lubricous, nearly equalling those of Spirogyra nitida, but with much
longer articulations. When young the colour is of a dull pale green,
and about three imperfectly spiral lines of shining granules are with
difficulty distinguishable. Afterwards these lines become more con-
spicuous, the rest of the filament being now perfectly colourless, and
their component granules larger, but their arrangement is still irregular.
The filaments subsequently unite here and there, not by every articula-
tion, and their connecting processes are usually nearer to one end of the
vessicle than to the other. Such filaments are divaricated at the points
of connection. In some of the combined articulations the contents
appear unchanged, in others they form a mass of larger granules than
in the lines, and some have a large oval sporidium which often swells
the joint. Some traces of unchanged lines occur, now and then, in the
fructifying vessicles." — English Botany, 2nd ed., p. 176.

Plate XL, fig. 1. «, sterile c^lls X 200; b, c, d, e, conjugating cells
X 200 ; /, zygospore X 400. After De Bary.

GENUS 47. ZYGOGONIUM. Kwtz. (1843.)
Cells cylindrical or barrel-shaped, with a compact, often many-
layered glittering cell-wall. On each side near the middle an
irregular chlorophyll body, each furnished with a starch granule,
both often confluent in an axile string (in the very thick-walled
cells usually concealed by granules). Connection of the copu-
lating threads ladder-like. The protuberances of the two con-
tiguous inter-growing threads that receive the chlorophyll-
contents are bounded by partitions into fructifying-cells, which
then coalesce into a not-contracted zygospore.

Zygogonium ericetorum. De Bary Conj. p. 79.

Sterile cells, 1^- to 2 times as long as broad.

Zygospores subglobose or oblong, sporoderin rather thick,
even.

SIZE. — Cells -013 to -018 mm. diam. Zygospore -013 x '025
mm.

var. a. terrestris.

Zygogonium ericetorum, Kutz. Tab. v. t. 10, Dickie Bot. Guide, .
296. Jenner Fl. Tunb. Wells, 184. Hass. Alg. 174, t. 41,
f. 1 , 2.

Zygogonium torulosum, Kutz. Tab.v. t. 14.

Conferva ericetorum, Eng. Fl. v. 350 ; Harv. Man. 125 ;
Dillw. Conf. 1. 1, Eng. Bot. 1st Ed., t. 1553, 2nd ed. t. 2473.
Grev. Fl. Ed. 318. Grev. Crypt. Fl. t. 261 (?) Mack. Hib.
224. Fl. Devon, ii. 51. Hook. Fl. Scot. ii. 81.

Conferva alpina, Eng. Fl. v. 350. Harv. Man. 125. Grev.
Sc. Crypt. Fl. t. 261, f. 2.

On heaths.

ZYGNEMACEJE. 99

var. b, Aquaticum.

Zygogonium didymum, Rabh. Hedw. 1, t. 3, f. 2.
Zygogonium Agardliii, Rabh. Alg. Eur. iii., p. 253.
Conferva purpurascens, Carm. Eng. Fl. v. 350. Haw. Man.
123. Mack. Hib. 224.

In pools, bogs, &c.

This is a very polymorphous species, some of the forms being terres-
trial, and always sterile, others are aquatic producing zygospores. The
old name of Zygogonium erictorum has been retained, but undoubtedly
all these various foi ITS belong to Zygogonium Agardhii) Rabh. (Zyg-
didymum, R.)

" The colour, no less than the condition of the endochrome, varies
considerably in this species. In some specimens the filaments are of a
bright green, in which case they have always been found immersed iu
water; while in others, and more frequently, they are purple, of which
colour they invariably are when found spreading over swampy heaths."
— Hass.

Plate XL. fy. 2. Terrestrial form. «, sterile cells X 100 Fig. 3.
var. aquaticum. a, sterile cells X 400 ; b, c, conjugating cells with
zygospores X 400.

Doubtful Species.
Zygogonium gracile. Berk.

Sterile cells about five times as long as broad, of a pale or
yellowish green colour.
Zygospore unknown.
SIZE. Cells -014.--016 mm. diam.
Rabh. Alg. Eur. iii., 255.
Zygnema gracile, Berk. Glean, t. 12, f. 3.

Face of a dripping rock.

Rabenhorst includes this with uncertain species of Zygogonium, but it
seems more probable that it is a Zygnema, and perhaps one of the
varieties of Z. Vauclierii. The following is the original description : —

" Pale dirty yellowish green, mucous ; threads extremely fine, articula-
tions not at all constant in length, 4 to 8 times as long as broad, marked
in the centre with two approximate roundish globules. Slender fila-
ments occur in the same mass, with joints longer in proportion, the
green mass not divided into two distinct portions. I have not seen it
conjugated." — Berkeley.

Plate XL. fig. 4. Sterile cells X 400.

GENUS 48. MOUGEOTIA. De Bary. (1858.)

Cells with axile chlorophyll-plates. Copulation ladder-like.
Zygospore drawn together in the swollen, bladdery, persisting
middle space.

De Bary includes this genus in Zygnemeos, although Wittrock joins it
with Mesocarpus, and it seems to us very difficult to indicate any true
generic distinction apart from the dividing off from the parent cells of
the empty persistent cells which remain some time attached to the zygo-

P

100 ZYGOPHYCEJE.

spore ; nevertheless we have not followed Wittrock in uniting Mou-
geotia, Mesocarpus, Pleurospermum, Craterospermum, and Stauros-
permwn under the one genus, HfoiM/eotia,, because we think that there
are sufficient characters to warrant the retention of Staurospermum
apart from Mesocarpus. If the mode of development in the following
two species is accurately appreciated, this genus is more allied to Zygo-
ffonium than Mesocarpus. See Archer in Quart. Micro. Journ., 1866,
p. 271.

XVXougeotia glyptosperma. DeSary Conj. p. 78, t. 8,f. 20-25.

Sterile cells 7 to 12 times as long as broad.

Zygospores large, oval, with a thick, firm, yellow-brown
epispore.

Sporiferous cells elongated.

SIZE. Cells 'Ol-'Olo mm. 6 to 10 times as long. Zygo-
spore -016X-035 mm.

Rabh. Alg. Enr. iii. 255. Archer in Quart. Journ. Micr.
Sci. 1866, p. 65.

As pointed out by Mr. Archer (loo. cit.) " this plant is not truly a
Mesocarpus, but in its mode of conjugation more nearly approaches
certain Zygnemata. It is no doubt related, on the one hand to Meso-
carpus (Hass.) ; like it the endochrome forms a compressed longitudinal
band, and like it too, the zygospore is formed half-way between the two
conjugating joints. But, it is distinguished strongly by the fact that
here the whole cell contents 'primordial utricles' and all, of the two
conjugating joints completely coalesce, leaving the old cell-walls empty,
in order to form the zygospore ; whilst in Mesocarpus the contact of the
primordial utricles of the two conjugating cells is not followed by a
complete coalescence of the two into the zygospore ; but by a concen-
tration of the principal part of the green and solid contents in the con-
necting canal half-way between the two joints, and the shutting off
thereupon of the residue of the pale granular contents remaining in each
parent joint, the denser central portion becoming the spore, and that
cut off on each side eventually becoming effete and lost. Hence in
Mougeotia glyptosperma the spore is the actual result of the complete
fusion of the entire cell contents of the two conjugating joints — it is
the true zygospore ; whilst in Mesocarpus the ultimate spore is a
daughter. cell, as it were, of the zygospore. Therefore, on the other
hand, the present plant shows an affinity to Zygnema ; but it is, of
course, completely distinct in the flattened band of endochrome, not
doubly stellate, as in that genus, not to speak of the extremely different
comparative length of the cells, which, within the limits of each, is
constant."

Plate XLI. fig. 1. a, sterile cells X 400 ; b, c, conjugatiag cells with
zygospores, after De Bary, X 200 ; d, zygospore, after DeBary, X 400.

Mougeotia lesvis. Archer Micr. Journ. 1867 t. 8, f. 1-3.
Sterile cells twice as long as broad.

Zygospores broadly elliptic or oval. Epispore thick, brown.
Sporiferous cells sometimes elongated.

SIZE. Cells -02--25 mm. Zygospore about -045 x -036 mm.
Rabh. Alg. Eur. iii. 255. Archer Micr. Journ. 1866, p. 270.
Zygogonium Iceve, Kutz. Tab. v. t. 13.

In ditches and pools.

ZYGNEMACE.E. 101

Mr. Archer has thus described the present plant : — " Cells short, vary-
ing from nearly quadrate to three or four times longer than broad,
according to the interval of time elapsed since division ; the contents
bright herbaceous green, forming an axile compressed band (never sepa-
rate stellate chlorophyll bodies as in Zyynema) ; the conjugation taking
place by short wide processes, which, along with the shortness of the cells
or joints, gives the pair of conjugating filaments somewhat the appearance
of a perforated ribbon-like structure ; the total cell contents of each
pair of conjugating joints became massed together into an elliptic zygo-
spore within the inflated transverse tube ; the longer diameter of the
zygospore placed vertically to the length of the filaments ; the cavity
occupied thereby not shut off by any septum from the cavities of the
parent joints. It was evident that there was no septum separating the
zygospore from the cavities of the parent cells, but it lay freely in the
inflated transverse process, though frequently in contact with its walls
about the middle."

Plate XL1. fi.g. 2. a, sterile cells X 400 ; b, fertile cells with zygo-
spores X 200. *

Sub- Family 2. MBSOOARPEJI.

Cells cylindrical, united in threads, with axile plates of
chlorophyll. Zygospore the shape of the mother-cells ; not
contracted, separating by three to five partitions into a central
firm-walled resting spore, and two or four lateral decaying
cells.

The method of conjugation and spore-formation in the Mesocarpce was
not thoroughly understood until it was investigated and explained by
De Bary (" Conjugaten," 1858), who first recommended the separation
of the Mesocarpece from the Zygnemeas, and their recognition as separate
families. His exposition of the conjugation of the Alesocarpece is thus
summarised by Wittrock* in a memoir submitted to the Swedish Academy :
— "Two cells grow together in the common manner by conjugation out-
growths, and a resorption of the double septum between the two conjuga-
ting cells takes place. By this a cruciated or H-shaped double cell is
formed, in which at first no other change takes place than that the canal
of conjugation is somewhat widened, and that the chlorophyll-coloured
part of the contents of the double cell moves into the canal of conjuga-
tion, and into the parts of the double cell nearest to the canal. This
cruciated or H-shaped cell, thus formed immediately by the conjugation,
De Bary regards as the zygospore of the Mesocarpece, and gives it the
character of being ' not contracted ' in contrast with the zygospore of
ZygnemecB and Desmidiece. This zygospore exists, however, only for a
very short time as such. The above-named moving of the chlorophylla-
ceous bodies (not of the whole protoplasmic mass) into the connecting
canal having been accomplished, the zygospore is divided by two or four
septa into three or five cells, of which one, the central one, is a hypno-
spore, rich in chlorophyllaceons protoplasm (and later in oil), whilst the
two or four lateral cells, containing no chlorophyllaceous protoplasm, are
sterile, and soon going to die. Thus the Mesocarpece have, according to
De Bary, spores of two kinds, namely (1), zygospores, which are formed

* "On the Spore-formation of the Mesocarpese." By V. B. Wittrock. Stockholm,
18/8.

102 ZYGOPE1YCE.E.

simply by the growing together of the two conjugating cells, without
contraction, and which do not rest, and (2) hypnospores (resting spores),
which are formed by the partition of the zygospores, and which rest (as
the name indicates) for a time before germinating. The Zygnemece and
Desmidiece have, on the contrary, according to De Bary, spores of only
one kind, namely, typical zygospores, in the formation of which a fusion
and contraction of the whole protoplasmic contents of the conjugated
cells takes place, and which become hypuospores without a preceding
partition/'

Wittrock adds: — "To me it seems perfectly clear that De Bary is
quite right in saying that the hypnospores of the Mesocarpece are not
analogous to the zygospores of the Zygnemece, or in other words, that
they are not zygospores at all. The hypnospores of the Mesocarpece are
formed by partition, and not by an immediate fusion of the protoplasm
of conjugating cells, as the case ought to be with zygospores."

He then proceeds to refer to Pringsheim's observations on this subject
with commendation ('' Jahrbucher " xi., 1877). "The act of conjuga-
tion may be divided into two different stages. The first, being properly
speaking only introductory, consists in the two cells which participate in
the conjugation growing together by conjugation outgrowths, and the
septum between the cells thus growing together being resorbed. This
part of the act of conjugation is what Pringsheim calls copulation. The
second stage consists in an intimate fusion taking place of the proto-
plasmatic contents of the conjugating cells. This fusion is effected here
in the Mesocarpece principally through the moving of the chlorophyll
coloured parts of the protoplasm (the chlorophyllaceous bodies) into and
to the neighbourhood of the somewhat widened conjugation canal. This
second and more important stage of the fecundation Pringsheim calls
connubium. The conjugation having taken place in this manner, its
effect appears by the tripartition or quinquepartition of the cruciated or
H-shaped cell formed by the copulation. Of the cells formed by this
partition, the central one is fertile, the two or four lateral ones sterile.
The result of the conjugation is consequently not one cell, but several
cells, and not cells of one kind, but of two, namely, one propagative cell
(a spore), and around it two or four cells not capable of germination. It
would be difficult to find a reasonable interpretation of such a result, save
the one suggested by Priugsheim, of its being a sporoearpiwrn, and to me
this interpretation seems not only reasonable, but perfectly natural, for
although the sporocarpium does here remain on a very low, not to say
the very lowest, stage of development, it does, however, already possess
the constituent parts of a typical sporocarpium. It has a nucleus and
a pericarpinm, or at least an equivalent to one. The nucleus is the
single central spore-cell, and the ,pericarpium is represented by the two
or four lateral sterile cells.''

" If the explanation given above is accepted, the essential difference
betreeu these Algae and their nearest relations, Zygnemece and Desmi-
diece, might be expressed in the following manner: — The result of the
connubium in the former is a sporocarpinm (and their spore is conse-
quently a carpospore), but the result in the latter is a zygospore."

Wittrock then proceeds to show that in one species the formation of
the spores can take place equally in the manner of Mesocarpns, Playio-
spermum, and Staurospermum, equally by tripartition, quadripartition,
and quinquepartition, and hence he concludes that those genera are not
sound, and that all three should be included under sub-sections of the
same genus. We have not followed this suggestion, but have retained
Mesocarpus and Staurospermuni as distinct, relying upon the difference
of form in the central cell.

For further details we refer the student to the Memoir from whence
the foregoing observations are abstracted.

ZYGNEMACE^E. IGo

GENUS 49. MESOCARPUS. Hass. (1845.)

Spore sphserical or oval, between two cylindrical, straight or
slightly in-bent lateral cells. (a) Copulation ladder-like,
threads free, or with one end attached ; (b) copulation lateral
between two neighbouring cells of a thread, rarely ladder-like.
Sterile cells often with a knee-like bend, and intergrown at the
bend with similar cells of another thread.

Including also the genera Pleurocarpus and Craterospermum of Braun.

t Spore membrane scrobiculate or punctate.

M. nummuloides, Hass.

M. depressus, Hass.
tt Spore membrane smooth.

M. parvnlus, Hass.

M. recurvus, Hass.

M. scalaris, Hass.

Sub-gen. Pleurocarpus, Braun.

M. pleurocarpus, De Bary.

t Spore menibrane scrobiculate or punctate.
Mesocaxpus nummuloides. (Hass.) De Bary.

Sterile cells 7-14 times as long as broad. Zygospore spheri-
cal, or broadly ovoid ; membrane brown, scrobiculate.

SIZE. Cells -015mm. diam. Zygospore '044 X -034 mm.

De Bary Conj p. 80, t. 8, f. 9, 10. Cleve Mon. Zyg. p.
30, t. 9, f. 4, 5. Hass. Alg. 169, t. 45, f. 1. Rabh. Alg.
Eur. iii. 257.

Sphcero carpus nummuloides, Hass. Ann. Nat. Hist. xii. 187,
t. 7, f. 12.

In ditches. Fruiting in September.

Plate XLI. Jig. 3. a, sterile cells X 400 ; b, fertile cells, with zygo-
spores, X 400.

XKesocarpus depressus. Hass.

Sterile cells 7-12 times as long as broad. Zygospore ellipti-
cal, compressed ; membrane brown, punctate.

SIZE. -007--015 mm.

Hass. Alg. 168, t. 44, f. 1. Jenner Fl. Tunb. Wells 184.

Sphcerocarpus depressus, Hass. Ann. Nat. Hist. xii. 186, t.
7, t. 11.

var. B. ovalis. Rabh. Alg. Eur. in. 257.

Mesocarpus ovalis, Hass. Alg. 169, t. 44, f. 2.
Sphcsrocarpus ovalis, Hass. Ann. Nat. Hist. xii. 189, t. 7, f.
15.

In boggy waters.

104 ZYGOPHYCE.E.

There seems to be no specific difference between the two species of
S. depressus and S. ovalis of Hassall, the only feature relied upon being
that the filaments in the latter are scarcely more than half the diameter
of the former.

Plate XLI. fig. 4. «, sterile cells X 400 ; b, fertile cells, with
zygospores, X 400. ]?iq. 5, var. ovalis. a, sterile cells X 400 j b, fertile
cells, with zygospores, X 400.

tt Spore membrane smooth.
Mesocaxpus parvulus. (Hass.) De Bary.

Sterile cells 5-12 times as long as broad. Zygospore spheri-
cal ; membrane even, commonly twice the diameter of the
threads.

SIZE. Cells -01 mm. Zygospore -02--024 mm.

De Bary Conj. p. 80, t. 2, f. 15. Cleve Mon. Zyg. p. 31, t.
9, f. 6,7. Hass. Alg. 169, t. 45, f. 2, 3. Jenner Fl. Tunb.
Wells 184.

Sphcerocarpus par-rulus, Hass, Ann. Nat. Hist. xi. 434, t. 7,
f. 13, 14.

Mougeotia splendens, Kutz. Tab. Phy. v. p. 1.

var B. angustus. Hass.

Mesocarpus parvulus, var. tenuissima, De Bary Conj. t. 11, f.
10-14.

Mesocarpus angustus, Hass. Alg, 170, t. 45, f. 4.

Sphcerocarpus angustus, Hass. Ann. Nat. Hist. xii. 187, t. 7,
f. 16.

Mixed with other Algre, in ponds, &c.

Plate XLII. fig. 3. a, sterile cells X 400 ; b, c, fertile cells, with zygo-
spores, X 400. Fig. 4, var. an g list us. a, sterile cells X 400 ; b, fertile
cells, with zygospores, X 400 ; c, mature zygospore X 400.

Mesocarpus scalaris. (Hass.) De Bary.

Sterile cells 2-4 times as long as broad; zygospore spheri-
cal or broadly ovoid ; membrane brown, even, about equal in
diameter to the threads.

SIZE. Cells -034 mm. diam. Zygospore '034 mm. diam.

De Bary Conj. p. 80. Cleve Mon. Zyg. p. 32, t. 9, f.
11, 12. Hass. Alg. 166, t. 42, f. 1. Hass. Ann. Nat. Hist. x.
p. 45; xii. t. 7, f. 7. Rabli. Alg. Eur. iii. 257. Kutz. Tab.
Phy. v. t. 5.

Mesocarpus intricatus, Hass. Alg. 1 67, t. 43, f. 1. Jenner
Fl. Tunb. Wells 184.

tiphcerocarpus intricatus, Hass. Ann. Nat. Hist, xii, 186, t.
7, f. 9.

In boggy pools, &c.

ZYGNEMACE.E. 1U5

We can recognize no plausible grounds on which the M. intricatus of
Hassall can be maintained as a species distinct from M. scalaris.

Plate XLI I. fig. I. a, sterile cells X 400; b, conjugating cells, with
zygospores x 400.

JVIesocarpus recurvus. Hass.

Sterile cells 5 to 10 times as long as broad.
Zygospore globose. Sporoderm brown, even.
SIZE. '012-'018 mm. Zygospore '023 mm. diam.

Hass. Alg. 168, t. 44, f. 1. Rabh. Alg. Eur. iii. 257.
Sphcericarpus recurvus, Hass. Ann. N. Hist. xii. 186, t. 7,f. 10.

In ditches.

Plate XL II. Jig. 2. a, sterile cells X400; 6, conjugating cells with
zygospores X 400.

Sub-Genus PLEUROCARPUS. Braun.
Mesocarpus pleurocarpus. De Bary Conj.p. 81.

Sterile cells 2 to 3 times as long as broad.

Zygospores subglobose, brown, even.

SIZE. Cells -025-'03 nun. Zygospore -03 mm. diam.

Pleurocarpus mirabilis, Braun. Alg. Uni. p. 60. Rabh. Alg.
iii, 258.

Zygogonium pleurospermum, Kutz Tab. v. t 13.

Mougeotia genuflexa, Ag. and others. Eng. Fl. v. 360. Eng.
Bot. Ed. 11. t. 2505. Jenner. Fl. Tunb. Wells, 182. Hass.
Alg. 172, t. 40, f. 2. Harv. Man. 141. Mack. Fl. Hib. 231.
Dickie Bot. Guide, 296.

Conferva genuflexa, Dillw. Conf. t. 6. Eng. Bot. Ed. 1, t.
1914.

Zygnema genufiexum, Johnst. Fl. Berw. ii. 257. Grev. Fl.
Ed. 320.

Serpentaria genuflexa, Gray Arr. 1, 300.

var. compressus.

Mougeotia compressa, Eng. Fl. v. p. 360. Eng. Bot. Ed. 2,
p. 172. Harv. Man. 141.

Zygnema compressum, Lyngb. Hyd. Dan. t. 58.
Serpentaria compressa, Gray Arr. 1. 300.
Pleurocarpus compressus, Rabh. Alg. Eur. iii. 258.

In moor pools, &c.

This widely diffused species forms vast yellowish-green masses, which
Harvey says are often thirty feet in diameter ; we have often met with
them covering several square feet. The filaments are fragile, soon
breaking into short lengths, bent almost at right angles and united at the
angles, hence the old name of Mougeotia genuflexa.

Plate XL III. fc/. 1. Cells in conjugation X 400; 6, fertile cells
with zygospore, after De Bary X 400; c, c, zygospores X 400.

106 ZYGOPHYCE.E.

GENUS 50. STAUROSPERMUM. Kutz. (184,5.)

Spores four cornered, between the truncated corners of four
sessile lateral cells (cells of all the species up to twenty times
longer than broad.)

t Sporoderm porose.

S. quadratum, Hass,
ft Sporoderm verrucose.

S. gracillimum, Hass.
ttt Sporoderm smooth.

S. capucinum, Kufe.
S. viride, Ruiz.

f Sporoderm porose.
Staurospexmum quadratum. (Hass.) De Bary.

Sterile cells 10 to 20 times longer than broad.

Epispore quadrangular, with the angles truncate, not repli-
cate, sides straight, covered with large pores (about 50 on the
longer side).

SIZE. Cells -015-'02 mm. Zygospore -04--044 mm.

De Bary Conj. p. 81, t. 8, f. 11. Cleve Mon. Zyg. p. 34, t.
10, f. 3. Kabh. Alg. Eur. iii. 259.

Staurocarpus quadrangulatus, Hass. Ann. Nat. Hist. xi. p.
434. Jenner. Fl. Tunb. Wells, 184.

Staurocarpus quadrat us, Hass. Alg. 178, t. 48, f. 1.

Mougeotia quadrangulatus, Hass. Ann. Nat. Hist. xii. 185,
t. 7, f. 3.

In ponds, ditches, &c.

Plate XLIII. fig. 2. a, sterile cells X 400 ; b, 6, conjugating cells
with zygospores X 400.

ft Sporoderm verrucose.
Staurospermum giacillimum. (Hass.)

Sterile cells 8 to 15 times as long as broad, pale yellowish
green.

Zygospore quadrate, the sides deeply sinuate, angles retuse.
Sporoderm verrucose.

SIZE. Cells -006 '008 nim. Zygospore -02 mm. diam.

De Bary Conj. p. 81. Babh. Alg. Eur. iii. 260.
Staurocarpus grftcillimus, Hass. Alg. 179, t. 49, f. 2. Jenner
Fl. Tunb. Wells, 184. Hass. Ann. Nat. Hist. xii. 185, t. 7, f. 6.

In bogs and moor pools.

Plate XLIII. fig. 3. a, sterile cells X 400 ; I, conjugating cells with
zygospores X 40*0.

ZYGNEMACE.E. 107

tff Sporoderm smooth.
Staurospexmum capucinum. Kutz.
Sterile cells 6 to 14 times as long as broad.
Zygospore quadrate, angles obtuse or truncate, sides often
deeply sinuate. Sporoderm even.

SIZE. -015 X'02 mm. Zygospore -05 X '04 mm.

De Bary Conj. p. 81. Rabh. Alg. Eur. iii. 259.

Staurocarpus glutinosus, Hass. Alg, 177, t. 47, f. 1.

Staurocarpus ccerulescens, Hass. Alg. t. 47, f. 2. Jenner Fl.
Tunb. Wells, 184.

Mongeotia glutinosa, Hass. Ann. Nat. Hist. xxii. t. 7, f. 1.

Staurocarpus capucinus, Hass. Ann. Nat. Hist. xii. p. 184,
t. 7, f. 2.

Mougeotia ccerulescens, Eng. Fl. v. 360. Harv. Man. 141.
Eng. Bot. Ed. 2, t. 2506.

Conferva ccerulescens, Eng. Bot. t. 2457.

Agardhia ccerulescens, Gray AIT. i. 299.

Leda capucino, Bory in Mong. & Nest. Ex. 793.

In ditches and ponds.

The filaments soon acquire a bluish tinge, and in drying assume a
purple hue.

Plate XL1V. Jig. 1. a, sterile cells X 400; b, conjugating cells with
zygospores X 400.

Staurospermum vixide. Kutz.
Sterile cells 10 to 20 times as long as broad.
Epispore quadrangular, angles truncate and replicate, sides
concave, smooth.

SIZE. Cells -008 mm. Zygospore '025 mm.

De Bary Conj. p. 81, t. 2, f. 17-18. Cleve Mon. Zyg. p. 34,
t. 10, f. 4-5. Eabh. Alg. Eur. iii. 260.

Staurocarpus gracilis, Hass. Ann. Nat. Hist. xii. 185, t. 7,
f. 5. Hass. Alg. 179, t. 49, f. 1. Jenner Fl. Tunb. Wells, 184.

Staurocarpus virescens, Hass. Alg. 178, t. 48, f. 2.

Staurocarpus qffinis, Hass. Ann. Nat. Hist. xii. 185, t. 7, f. 4.

Staurospermum franconicum, Reinsch. Algen. Fl. p. 217.

In ditches.

Plate XL1V. fig. 2. «, sterile cells X 400; 6, conjugating cells
with zygospores X 400; c, development of zygospores from conjugated
cells X 400, after De Bary,

Sub- Family 3. GONATONEME^:.

Cells cylindrical, much elongated, united in threads, with
axile plates of chlorophyll. Agamospores produced without
conjugation in cells continuous with, and partitioned from the
mother cells.

Q

108 ZYGOPHYCE.E.

Wittrock includes his single genus Gonatonema in the Mesoearpets as
an agamosporous form, without ascertained conjugation. As an excuse
for this he says: — "If we attached importance only to the neutral or
sexual nature of the spore formation, as some of the modern systema-
tizing botanists do even in the lower GryptogaMiCB, we should be obliged
to form a separate family for it, which might not even be placed in the
class of Conjugates. To me the accordance with Mesocarpece as to
the vegetative cells and the formation of the spores seems too great to
allow the separation of Gonatonema from this family. It may not be
unnecessary here to call to mind that the class of Diatomacecs in which
the formation of spores is in general effected through conjugation, does
also embrace some genera where the spores are formed neutrally."

At the risk of condemnation as a " modern systematizing botanist," we
do not feel content to include this genus in the Mesocarpea, and have
therefore relegated it to a separate family until more complete evidence
is furnished as to whether it really should be associated with the Conju-
gate at all, although its affinities seem to lie in that direction. All we
are justified by the facts to assume is that it is an aberrant form, which,
on the faith of its vegetative character may for the present be retained
in proximity to the Mesocarpea? until its relationship is better established.

GENUS 51. GONATONEMA. Wittrock. (1878.)
Spores (agamospores not carpospores) without conjugation,
formed by biseptation of the mother cells, which latter are bent
angularly, and alternately, at the point of fructification.

Wittrock illustrates this genus by means of a species not yet ascer-
tained to be British, but which he regards as congeneric with Hassall's
species hereafter described. "Its vegetative stage consists of cylindric
cells arranged in a single row. The membrane of the cells is very thin,
and consists of pure cellulose. The bottoms of somewhat older cells
are gently curved inwards, which gives rise to a small lens-shaped room
between the cells. The contents of the cells consist of (1) a parietal
thin colourless layer of protoplasm ; (2) an axile cholrophyll-coloured
rather thick bard of protoplasm (the single chlorophyllaceous body of
the cell) which runs through the whole length of the cell, and which is
most frequently more or less excavated at both ends of the cell ; in the
band of chlorophyll occur the so-called ' starch granules,' in a number
of 2 to 4 ; (3) a rounded nucleus, which has its place at the side of the
chlorophyllaceons body, or very often in a small circular opening in the
middle part of the band of chlorophyll ; (4) small drops of oil, attached
partly to the inner side of the parietal layer of protoplasm, and partly
to the outer side of the chlorophyllaceous band ; and (5) colourless cell
liquid, which fills the vacuoles between the parietal layer of protoplasm
and the axile chlorophyllaceous band.

" In purely vegetative cells the chlorophyllaceous body is found to pos-
sess the power of making free, and rather quick movements. This species
thus gives a second instance of independent movements of chlorophyl-
laceous bodies belonging to vegetative cells.

" The formation of vegetative cells takes place by bipartition, exactly
in the same manner as in the llesocarpece. The cells destined to bring
forth spores have always a very considerable development as to length.
While the vegetative cells just formed by bipartition are only 5 to 6
times as long as thick, the cells which are ready to form spores are at
least 9, and more often 12 to 16 times as long as thick. A rather con-
siderable increase as to volume, by development in length, does conse-
quently take place in these cells before they are capable of fulfilling
their propagative purpose.

ZYGNEMACEJS. 10 9

" The first sign of a beginning spore -formation is that the cell widens
at its middle, so that this part resembles a cask. This widening is not,
however, equally powerful on all sides, but is stronger on one side than
on the other sides. At the same time the cell bends at its middle like a
knee, so that its two halves form a more or less obtuse angle with each
other. The point of the angle is placed where the before-mentioned
more powerful widening of the cell has taken place. Almost always the
formation of spores takes place at the same time in all the cells of a
filament. Then it regularly occurs that the cells bend alternately in
opposite directions, so that if cell No. 1 bends to the right, cell No. 2
bends to the left, No. 3 to the right, and No. 4 to the left again, and so
on. Consequently the cells in a filament-producing spores will form a
zig-zag line. Exceptions from this rule do, however, now and then
occur ; thus, that two cells abutting on each other bend in the same
direction, after which the two next bend in an opposite direction and so
on. When this occurs, the filament is gently curved like an S, alter-,
nately in two directions. When the spore-forming cell widens and
bends, the chlorophyllaceous band of the cell is often interrupted at its
middle part, by which the cell gets two chlorophyllaceous bodies instead
•of one. The chlorophyll -coloured protoplasm now begins anew to give
proofs of its power of free motion. The chlorophyllaceous body (or
bodies if there are two) moves freely and rather quickly, from the other
parts of the cell to the widened middle part. When all of it has entered
this part of the cell, which has thus become almost quite filled with
chlorophyll-coloured protoplasm, the cell is divided into three cells by
two septa, appearing one on each side of the chlorophyll filled central
part. The cells formed by this partition are of two essentially different
kinds. The two lateral cells have very little living contents. All the
chlorophyll-coloured protoplasm is gone, and only the thin parietal layer
of protoplasm and some drops of oil are left. The rest of the contents
are only colourless cell-liquid. These cells have in fact filled their pur-
pose. They soon die, and remain, as mere skeletons of cells, attached
for some time (two or three weeks) to the central cell. The central cell is,
in contrast to the lateral cells, very rich in living contents, having re-
ceived all of the chlorophyll-coloured protoplasm of the mother-cell. It
is also designed to become the hypiiospore, through which the propaga-
tion of the species is to be affected. But before it becomes a complete
hypnospore it is to pass through several stages of development. The
first of these is that the cell-contents surround themselves with a new
layer of cellulose (me&osporium) within the original one (exosporium).
The mesosporium increases by-and-bye in thickness till it is considerably
thicker than both the exosporium and the endosporium (which appears
later). The mesosporium gets no sculpture (as is the case with so many
Mesocarpea*) it remains always smooth. But having been at the begin-
ning hyaline, it soon assumes a faint yellow colour. Within the meso-
sporium a new layer of cellulose forms during the first week ; this is
called endosporium. It remains always hyaline and very thin. During
this time the contents of the cell have also suffered a change. The
chlorophyll-coloured protoplasm, at least the greater part of it, has
changed into a fat oil, which is coloured in the same manner as the
mesosporium, i.e., a faint yellow. The hypnospore which is now
ready, shows a somewhat different shape, if regarded from different
sides. If regarded in the position it has when the curvatures of the
spore-forming filament are directed to the right and left of the ob-
server, the spore is, as a rule, non-symmetrically elliptic, with abrupt
ends, very seldom it is almost circular. The want of symmetry con-
sists in the spore being more convex on the side towards which the knee
of the mother-cell has bent. If we imagine the spore being turned a
quarter of a turn round its longitudinal axis, it appears somewhat

110 ZYGOPHYCE.E.

narrower, and perfectly elliptical, with abrupt ends. How the spores
behave when germinating I have not yet had any opportunity of observ-

" Thus it appears from the foregoing details that the spores are always
formed without a preceding act of conjugation. The spore formation,
therefore, may be regarded as neutral, or we may assume that as in
exceptional cases spores may be formed by the instrumentality of a
single cell, in this ease the exception has become the rule, and the spores
would then be regarded as parthenospores, and not as agamospores."

Under these circumstances of development, Wittrock considers him-
self justified in proposing the genus Gonatonema for the two forms, the
one Gonatonema ventricosum, on which the above observations were
made, and the other the species which Hassall described as Mesocarpus
notabilis.

Gonatonema notabile. (Hass.) fVittr.

Sterile cells 8 to 10 times as long as broad, sometimes longer.

Zygospore, front view cylindrical, side view bent so as to be
convex on one side, concave on the other, truncate at the ends^
same diameter as the vegetative cells.

SIZE. Cells -012--015 mm.

Wittrock Mesocarpea3, p. 16, fig. 14.
Mosocarpus notabilis, Hass. Alg. 170, t. 46, f. 2.
Mougeotia notabilis, Hass. Ann. Nat. Hist. x. p. 46.
Staurospermum notabile, Rabh. Alg. Ear. iii. 261.

Found in great abundance in some brick fields near Netting
Hill. — Hassall.

Here follows the original description by Hassall : — " Filaments at first
cylindrical, but subsequently becoming angulated, the angle of flexion
being situate in the centre of each cell. Cells usually about 8 or 10
times as long as broad, but frequently longer. Sporangia non-symme-
trical, a single one being placed in the angle formed in each of the cells."

We have nothing to add to this description, never having seen the
plant in question, and are able only to reproduce Hassall's figures.

Plate XL1 V. fig. 3. a, sterile cells ; b, fertile cells, after Hassall.

BOTltYDIACEJU. Ill

ORDER III. SIPHOPHYCEJE.

Unicellular algse, usually at the time of fruiting bicellular.
Cells utricle-shaped, often prominently branched ; branches with
terminal vegetation, at length shut off by a septum, some trans-
formed into oosporangia, others into antheridia. Cell contents
green, mucilaginous, granulose, filled with chlorophyllose vesicles
and starch granules.

Propagation by free cell formation, or zoogonidia, or
oospores.

Plants aquatic or terrestrial, some marine.

FAMILY I. BOTRYDIACE.E. — Propagation by free cell for-
mation and by zoospores.

FAMILY II. VAUCHERIACEJE. — Propagation by oospores
and zoogonidia.

FAMILY I. BOTRYDIAOE^J.

Plants small, terrestrial, unicellular. Cell in the beginning
globose, afterwards clavate or pyriform, and inflated ; vertex
rounded, a long time closed, attenuated downwards ; base
divided into delicate hyaline radicles, filled within with a
mucilaginous green granulose cytioplasm, with age collapsing
at the apex, and finally wasting away. Cell contents modified
into an indefinite number of resting spores ; spore contents, in
germinating, becoming modified into a number of sexual zoo-
spores conjugating and forming isospores.

GENUS 52. BOTRYDIUM. Wallr.

Vegetative plants unicellular, increasing by cell division and
zoospore formation ; asexual uniciliate zoospores ; sexual bici-
liate isospores, sometimes globular, and alike capable of
germination, sometimes compressed and hexagonal, furnished
with a few.tuberculate thickenings.

See for information Braun's " Rejuvenescence," pp. 128, 193, 220,
274 ; Parfitt in " Grevillea," Vol.i., p. 103 ; Archer in " Grevillea," Vol.
i., p. 105 ; Eostafinski and Woronin, " Ueber Botrydinm granulatum,"
1877; Lawson in "Trans. Bot. Soc., Edinburgh," vi., 424 ; Archer in
" Quarterly Journal of Microscopical Science/' 1878, pp. 446-452.

R

112

The following is a summary of Rostafinski and Woronin's researches
on this germs : —

If a plant be placed in water, its contents become modified at the
latter part of the day or at night into zoospores. Ultimately the wall
swells, then bursts somewhere at the top, and the zoospores resulting
from the division of the parietal stratum escape. If the plant be only
moistened, the zoospores do not swarm out, but come to rest within the
collapsed wall. Such were known to previous observers as " germ
cells " or " gonidia."

The zoospores are elongate-oviform, 5-8 X 20 mm., with a single
flagellum, and 2 to 4 chlorophyll granules. Having swarmed out, they
soon come to rest, lose the flagellum, become surrounded by a mem-
brane, increase in size, and germinate on clamp earth, in which stage
they represent the so-called Protococcus botryoides.

The large ordinary zoosporangia are also otherwise modified. If one
is allowed to dry, its membrane collapses, loses colour, and soon becomes
empty. The protoplasmic contents pass down to the ramifications of
the root. Here they break up into numerous cells, sometimes two or
thi'ee side by side, but chiefly in a continuous chain ; each cell furnished
with a separate membrane.

These are capable of three forms of development: — (1) If removed
from the soil and placed in water, the cell becomes a subterranean
zoosporangium. The formation of the zoospores is independent of light
at any hour of the day or night. The zoospores are similar to those
above described, and germinate in the same manner. (2) If a chain of
these root cells be laid on moist earth, each protrudes a hyaline process,
which enters the soil, the opposite end being elevated, and thus each
root cell becomes a vegetative plant. (3) If the root cells are not
removed, and kept equably moist, they also germinate in the earth,
become inflated, put forth a root process, the wall of which becomes
very much thickened on the inner side below the inflated upper portion.
By interculary growth of the root portion the upper part becomes raised
aloft, so that the apex is carried above the surface of the soil. These
products of modified root cells are named hypnosporanges, and are equi.
valent to so-called Botrydium Wallrothii. When dried, the hypno-
sporanges retain their power of germination during the whole year, and
when placed in water form zoospores at any hour of the clay and night,
germinating and forming young plants as above,

The uniflagellate zoospores germinate on a moist substratum. On
earth or sand they thrive badly, but better 011 clayey or muddy soil. In
water they never germinate, but come to rest, are surrounded by a
double membrane, and lie dormant for months. If these be transferred
upon a clayey soil, they commence to form a vegetative plant. If the
zoospores be sparingly distributed over the soil, and the whole kept
equally moist, the vegetative plants become ordinary zoosporanges. The
plants are sometimes modified into hypnosporanges.

Thus, vegetative plants can be increased by cell division directly
from zoospores, become ordinary zoosporanges, with such consequences
as root cells, &c., or they may be directly modified into hypno-
sporanges. But there is yet another way in which existence may be
carried on. If exposed to drought, the following phenomena occur: —
The wall collapses more or less, and the protoplasmic contents break up
into a number of cells, each surrounded by a delicate membrane, its
contents homogeneous, at first green, then passing into red. These are
the spores, and have been known by such names as Protococcus coccoma,
P. palustris and P. botryoides. These spores become changed in water
to zoosporangia, their contents giving rise to zoospores in the manner
already described. If the spores be still green, their zoospores will
have a distinct fusiform figure, with two cilia at one end. They consist

BOTRYDIACE.E. 113

of slightly coloured protoplasm. Theso zjospores conjugate in twos,
sometimes several together. They come in contact by their ciliated
ends, then come to touch laterally by the uncoloured portions, when
the fusion of the conjugating zoospores takes place, immediately after
which they present a cordate figure, and in the middle a colourless
vacuole. Finally, the isospore thus originating becomes globular, the
vacuole occupying the centre.

If the zoospores be isolated before conjugation, they will in the end
break up, without presenting any products capable of germination.

The zoospores originating from red spores have a different figure,
their posterior end being rounded, but they have otherwise the same
structure, and behave in the same manner as the others. The red
spores maintain their germinative power for years, but after two years
their zoospores are languid, and offer a parthenogenesis of a peculiar
kind. The red spores, if kept moist only, become nothing altered after
weeks, whilst the green, under these circumstances, may directly
germinate into vegetative plants.

The isospores are at first globular, and capable of immediate germina-
tion. They also present resting stages, the original form becoming
modified. Soon after conjugation these are flattened, with irregular
lateral boundaries, which become on the following day hexagonal. The
membrane becomes thickened, and presents tuberculations at the
margin, but no secondary membrane is formed. Brought upon damp
earth, they soon become globular, and otherwise behave as ordinary
isospores.

In order to distinguish that which appertains to the cycle of alterna-
tion of generations from the rest, the simple method is to start from the
fertilized germ, and see what are the modifications which are essential
in order to arrive again at the same reproductive process. In this case
we have the isospore — it germinates — produce the vegetative plant,
which needs neither to divide, nor produce a sexual zoospore, nor to
become an ordinary zoosporange — it can directly produce spores. These
close the first generation. The second oospore generation occurs in the
germination of these spores in the form of sexual zoospores, which
directly lead to the formation of the isospore — the limits of two genera-
tions. All the rest are but phenomena of adaptation.

" Thus, in nature, the vegetative plants in spring almost all become
zoosporangia, and spread the growth over considerable areas. Zoospores
which fall into the water are not lost ; they acquire a double membrane,
and lie dormant until they chance mechanically to arrive on moist soil.
If drought sets in, the plasma retreats to the roots ; if the earth be
some time a little moist, the root cells become hypnospores, awaiting
the rain in order to develop multitudes of zoospores 5 but if the earth
becomes rapidly dried, the root cells remain unaltered, until a moistening
excites the formation of zoospores. A great many of the root cells can
manifestly accidentally reach the surface of the soil, and thus, according
to the state of the moisture of the earth or of the air, sometimes ger-
minate, sometimes become zoospores." All this in the spring. The hotter
months favour the formation of spores, but at that time only the
vegetative plants are mostly to be found, either undergoing cell division
or spore formation. They can also furnish uniciliate zoospores without
becoming modified into ordinary zoosporanges.

Formation of ordinary zoospores may be accomplished in a fourfold
way —

1. From the vegetative plant.

2. From the ordinary zoosporange,

3. From the root cell.

4. From the hypnosporange.

114 'SIPHOPHYCE.E.

Further modes of increase are —

5. Cell division.

6. Formation of spores.

7. Formation of zoospores.

This plant possesses also fivefold resting stages —

1. Of the asexual zoospores laid in water — for months.

2. Of the root cells — the year throughout in which they

originated.

3. Of the hypnosporanges — the year throughout in which they

originated.

4. Of the spores — for years.

5. Of the isospores — at least over the year in which they

originated.
y L~ V

Plate LXV., Botrydium granulatum. Fig. 1, plants of the natural
size. Fig. 2, zoosporaiigium X 30. Fig. 3, the same, five hours after-
wards, with the zoospores escaping at the apex, X 30. Fig. 4, zoospores
X 520. Fig. 5, differentiation of the plasma in the root, and the forma-
tion of root cells, X 30. Fig. 6, root cells in water producing zoospores
X 160. Fig. 7, the resulting zoospores X 520. Fig. 8, the same, 24 hours
after swarming, X 520. Fig. 9, the same, four days later, X 520. Fig.
10, the same, eight days later, X 520. Fig. 11, copulating swarmspores
X 520. Fig. 12, zoospores derived from a spore, after six and a half
hours, X 160. Fig. 13, sexual swarmspores in conjugation X 520. Fig.
14, isospores, 24 hours old, X 520. Fig. 15, stellate isospores, more than
a day old, X 520. Fig. 16, young plant resulting from vegetation of
isospore. All after Eostafinski and Woronin.

Botrydium granulatum. Linn.

Usually gregarious, often aggregated, rarely confluent ; cells
globose, pyriform, size of a poppy seed, or mustard seed, or
larger, leek-green, apparently pulverulent.

Botrydium granulatum, Jenn. Fl. Tunb. Wells 176. Parfitt
in Grevillea i., p. 10. Eng. Fl. v., p. 321. Harv. Man. 150.
Kirsch. Alg. Schl.,p. 84. Trans. Bot. Soc. Edin. vi., 424. Eng.
Bot. ii., p. 127, t. 2422. Hass. Alg. t. 77, f. 5.

Hydrogastrum granulatum,, Kabh. Alg. Eur. iii., 265. Desv.
Fl. Ang. 19.

Lichenoides fungiforme, Ray Syn. iii., p. 70.

Tremella palustris, Dillen. Hist. Muse. 55, t. x., f. 17.

Botrydium argillaceum, Grev. Alg. Brit., p. 197, t. 19. Kutz.
Tab. vi., t. 54.

Vaucheria granulata, Grev. Fl. Ed. 306. Gray. AIT. i., 290.

Vaucheria radicata, Hook. Fl. Scot, ii., 93.

Vaucheria multicapsularis, Harv. Man. 149. Gray Arr. i.,
252 (?).

Ulva granulata, Lightf. Fl. Scot. 976. Hull. Brit. Fl. 309.

Tremella granulata, Huds. Fl. Ang. 566. With. Arr. iv.,
80. Eng. Bot. i., t. 324.

On the ground in swampy places.

"The plant about H mm. diam. ; the upper portion, or that above
ground, globular, gradually narrowing downwards, and passing into one

VAUCHERIACEJ3. 115

or two principal roots, which become gradually ramified into many fine
rootlets; the chlorophyll contents at the beginning dense and homo-
geneous, and clothing the inner cell membrane, extend only to the neck
of the root ; the membrane is rather rigid. Upon being broken the cell
contents become extruded, the membrane collapses as a thick pellicle,
whose contents admit of being completely pressed out. The fluid
contents in this condition consist of finely granular plasma, tinged by
chlorophyll granules. Subsequently the green plasma layer becomes
separated from the membrane, breaks up into single equal-sized portions,
which become rounded off, coated with a membrane, and gradually
individualized as daughter-cells. At last the entire globose cell is
densely filled with rounded daughter-cells ; whilst, previous to this state,
the plant presented an intensely grass-green colour, it shows in this
latter state a clear or sea-green colour. Mature and immature plants
hence readily admit of being distinguished by the tint with the unassisted
eye. The membrane of the mother individual at last passes to decay ;
it collapses, and the daughter -cells become the germs of new indivi-
duals in the soil. The maturity of the individuals occurs towards
autumn, and accordingly the germ cells lie resting in the earth during
winter, and germinate in the following spring. The development of the
germ cells to new individuals takes place without formation of a
' prothallus ' ('ohne Vorkeimbildung '). One end elongating as a root,
at once penetrates the earth ; the other end becomes developed as the
above-ground portion. The diameter of a ripe germ cell is 0'009-0'012
mm. The plants prefer to establish themselves on the surfaces of the
large clefts which are produced when the waters retreat and the ground
becomes gradually dried by the air." — Reinsoh. Algeti Flora, p. 218.

See also " Grevillea" Vol. iv., p. 105, since which period the Memoir by
Eostafinski and Woronin has appeared, and that has pretty well estab-
lished the complex character of reproduction in this little plant.

FAMILY II. VAITCHEBIACE^E.

Algae monoecious (rarely dioecious), casspitose, unicellular or
bicellular. Thallus with terminal vegetation, utricle- shaped,
elongated, more or less branched.

Propagation either sexual, by oospores fecundated by sper-
matozoids, or non-sexual by zoospores.

Sporangium terminal, formed by the globosely clavate swelling
of the tip of the thallus, cut off by a septum, contents dark
green, at length enclosing one large zoospore, densely clad with
vibratile cilia.

Oogomum lateral, sessile, or borne on a more or less elongated
simple, or partite, pedicel ; cytioplasm at length converted into

a large oo spore.

Antheridiwn lateral, sessile, or cut off by a septum from the
upper portion of a lateral branch, in which numerous spermato-
zoids are generated, which at length become free. Spermatozoids
oblong, furnished with two unequal cilia (except in one
species).

116 SIPHOPHYCEJS.

Consult Thuret in "Anaalesdes Sciences Naturelles, Botanique," 1843.
Walz in Pringsheim's " Jahrbucher " for 1866. Braun "Rejuvenescence,"
pp. 128, 140, and following.

GENUS 53. VAUCHERIA. D. C. (1805.)

Characters the same as given above for the Family.

Two or three arrangements of the European species of Vauclieria have
been proposed, differing slightly in detail. The following is that of Pro-
fessor Norclstedt : —

VAUCHERIA.

A. Antheridia not separated from the thallus by a short empty
boundary cell.

a TuBULiGERyE. Antheridia little or scarcely bent, oblong
cylindrical, or lanceolate, with an opening at the top. Red
pigment bodies not collected in the middle of the mature
oospore. Oogonia and antheridia almost stemless.

* Oogonia nearly round.

1 V. dichotoma (L) Disecious.

2 V. ThuretiiWor. Moncecious.

** Oogonia not round, more or less oval,
frequently rather oblique.

3. V. aversa, Hass.

4. V. sericea, Lyngb.

6 COHNICULAT^. Antheridia bent in the form of a horn, or a
hook, placed on the short and bent side branches of the
thallus. Brown pigment in the middle of the mature
oospores.

aa Sessiles. Oogonia sessile (or with exceeding short
stems) beside the antheridia on the thallus.

5. V. Dillwynni, Ag.

6. r. sessilis (Vauch).

1)1) HacemoSfs. Antheridia at the end of a fruit branch,
which, somewhat lower down, carries the
oogonium.

* Oogonia turned upwards.

f Antheridia and oogonia bending in op-
posed planes, forming an angle with
one another. When the oospores
fall they are surrounded by the
oogonium membrane, which is not
changed to slime.

7. V. geminata, Walz.

8. V. hamata, Walz.

ff Antheridia and oogonia (mostly)
bending in parallel planes, the
oogonium membrane turns to slime
and dissolves.

9. V. terrestrisy Lyngb.

** Oogonia turned-downwards.

10. V. uncinata, Kutz.

c Antheridia straight, with the top covered, and a pair of fruiting
tubes standing out at the side.

11. V. De Bar y ana, Woron.

VAUCHERIACE.E. 117

B. Between the antheridia and thallus itself is found a shorter empty
boundary cell (not containing chlorophyll).

a ANDROPHOEJE, Several horn-shaped bent antheridia placed
on a swollen cell containing chlorophyll, which is fixed to
the side of the thallus, by means of the boundary cell.

12. V. synandra, Woron.

1) PILOBOLOIDEJE. Antheridia bordering immediately on the
boundary cell (frequently provided with several mouths).
aa Oogonium borders immediately on the thallus branch.
* Several fructification tubes on the
oogonium.

13. V. coroJiata, Nordst.
** Oogonium with only one fructification
opening, but the antheridia with
several,
f Oospore round.

14. v. intermedia, Nordst.

15. V. gphcerospora, Nordst.
f f Oospore lens-shaped.

16. V. piloboloides, Thur.
bb Below the oogonium a boundary cell.

17. V. litorea, Hofm.
Place uncertain.

18. Y. tuberosa, Br.

11). V. trifurcata, Kutz.

The sexual reproduction in Vaucheria has been minutely described by
Pringsheim, of which we give an abstract. Vaitcheria, besides the
asexual multiplication by zoospores also exhibits a true sexual propaga-
tion, effected by means of the two organs known as the " hornlets" and
the spores, the latter being more correctly termed " sporangium." Both
organs arise like papillary branches from the tube, and in close proximity.
It is usually the case that the papilla destined to become the hornlet is
formed sooner than that in which the sporangium originates. The two
papillge even from the first differ so widely in dimensions, that they can
scarcely be confounded. The papilla which becomes the hornlet soon
elongates into a short cylindrical slender branch, which at first rises
perpendicularly from the tube, then curves downwards until it comes in
contact with the tube, often forming a second, or a third curve, and in
this way always represents a more or less stunted branch, which fre-
quently exhibits several spiral turns. The papilla of the neighbouring
sporangium usually begins to appear at the time when the hornlet is
commencing its first turn ; but the period at which it arises is very
indeterminate, for it sometimes appears much earlier, whilst the hornlet
is still perfectly straight, sometimes much later after it has curved, so as
to form two limbs of equal length.

The papilla destined to become the sporangium gradually enlarges
into a considerable-sized lateral out-growth of the tube, far exceeding the
hornlet in width, whilst in length it is barely equal to the straight limb
of the latter. This out-growth which is afterwards symmetrical,
ultimately throws out a beak-like prolongation on the side looking
towards the hornlet, the rostrum of the sporangium, whence the latter
acquires its peculiar form, resembling that of a half developed vegetable
ovule. Up to this period the hornlet as well as the sporangium are not
shut off from the tube by any septum ; the cavity of the hornlet and that
of the sporangium consequently remain uninterruptedly continuous with
the parent tube, and are filled with similar contents. A number of
chlorophyll granules in an albuminous plasma and rounded oil globules,
constitute a dense lining to the tube, the sporangium, and the hornlet.
Between this and the cellulose membrane is the thin colourless cutaneous
layer.

118 SIPHOPHYCE^:.

At this stage a septum is suddenly formed at the base of the
sporangium, which is henceforth an independent cell, completely
separated from the parent tube. Even before this septation there may
be noticed in the rostrate elongation directed towards the hornlet, the
gradual accumulation of a colourless fine granular substance, of the same
nature as that with which the wall of the parent tube, and the
sporangium is lined on the inner surface, which has already been termed
the "cutaneous layer." This accumulation in the fore part of the
rostrum is continued after the formation of the septum between the
sporangium and the tube, and in consequence of its continued increase,
the remaining contents of the sporangium are by degrees pushed back
towards the base. Whilst these phenomena are being manifested in the
sporangium, the horulet also undergoes remarkable changes. In its
apex, the contents, owing to the disappearance of the chlorophyll, have
become almost colourless, more or less. Thus the point of the hornlet,
like that of the sporangium, appears at this time to be filled with a
colourless substance, which is not constituted by an accumulation of the
cutaneous layer, but manifestly arises from a molecular change
associated with an alteration of form and colour in the contents pre-
viously existing at the apex. So soon as the contents at the point of the
hornlet have thus become colourless, they appear to be constituted of a
very fine-grained granulose mucous substance. As soon as the trans-
formation of the contents has taken place, the colourless apex of the
hornlet is suddenly separated from the lower green portion by a septum,
and is thus transformed into an independent cell, without communication
with the parent tube. The point at which the septum is formed is not
very determinate, the portion cut off being sometimes larger, sometimes
smaller.

After the formation of the septum in the hornlet the colourless mucous
in its apex gradually assumes a more determinate form, and at
this time a large number of minute, perfectly colourless, rod-like
bodies may be readily perceived crowded together irregularty, and
as it were imbedded in the surrounding mucous. Close observation
will disclose an indistinct movement exhibited even thus early
by some of the little rods, from which their destination may be
anticipated.

This perfecting of the hornlet coincides with that stage of development
of the sporangium at which the accumulation of the cutaneous layer in
the anterior part of the rostrum has attained its greatest extent, and
these conditions immediately precede the act of impregnation, which is
effected in the following manner : —

The pressure within the sporangium, especially in the direction of the
rostrum, becomes greater and greater in consequence of the continued
increase of the cutaneous layer in the fore part, until ultimately the
membrane is ruptured exactly at the point of the rostrum,* and allows a
portion of the cutaneous layer to escape. The extruded portion
becomes detached, and assumes the character of a drop of mucous, which
remains lying near the openirg of the sporangium, and ultimately
perishes. The accumulation of the cutaneous layer in the fore part of
the rostrum, and the escape of a portion of it, are merely the mechanism
by which the opening is produced in the sporangium destined for the
admission of the sperm atozoids. Immediately after the formation of
this opening in the sporangium, and in remarkable coincidence Avith
the escape of the cutaneous layer through the rostrum, the hornlet opens
at the apex, and pours out its contents. Innumerable excessively minute
rod-like corpuscles ( 005 mm.), mostly isolated, escape at once through
the orifice. Those already isolated exhibit an extraordinarily rapid
movement in all directions, and those still imbedded in the mucous do not
become detached until afterwards, when they follow the others with,
equal rapidity. The field of view is soon covered with mobile corpuscles.

VAUCHEKIACEJ]:. 119

In great number (20, 30, or more) they enter the neighbouring orifice
of the sporangium, which they fill almost entirely, penetrating through
the portion of the cutaneous layer remaining, which, though without
any definite boundary, offers a solid resistance to their further penetration
into the sporangium. The corpuscles continue thus to struggle forwards
into the cutaneous layer for more than half an hour, bounding against
its outer surface they retreat, again push forwards, again retreat, and
so on, in an uninterrupted succession of assaults and retreats.

After this commotion has lasted some time, an abrupt boundary line
suddenly appears in the outer aspect of the cutaneous layer, the first
indication of a tunic forming around the contents of the sporangium
which were before bare. From this moment the mobile corpuscles are
separated from the cutaneous layer by a membrane which effectually
prevents their further action upon the contents. They continue, it is
true, to move to and fro, and this movement often lasts for hours
together, but at last they perish in the rostrum itself. Even after the
lapse of several hours the dead corpuscles may be seen in the rostrum,
lying on the front of the sporangium, until at last they are completely
dissolved, and all vestige disappears.

The cutaneous layer surrounding the green contents of the sporangium
becomes transformed, after impregnation, into the coat of the true spore,
which, thus formed, represents a large cell occupying the whole of the
sporangium, surrounded on all sides by the persistent tunic, which is
open in front and prolonged into the rostrum.

In this condition the spore remains for some time longer without being
thrown off from the parent tube on which it was produced, but the
colour of its contents gradually becomes paler and paler. The spore is
at last rendered quite colourless, and presents in its interior only one or
more largish dark brown bodies. When it has lost all colour it is
detached from the parent tube, in consequence of the decay of the
membrane of the sporangium enclosing it. After some time, say three
months, the spore suddenly resumes its green colour, and immediately
thereupon grows into a young Vaucheria exactly resembling the parent
plant.

An abstract of the memoir from which the above details were obtained
was published in the " Quarterly Journal of Microscopical Science " for
1856, (Vol. iv., p. 63).

During the present winter Mr. Frederic Bates, of Leicester, has called
our attention to some plants of V. scssilis, taken from beneath the ice
in a pool, The first feature which presented itself was the septation of
the threads, many of them being divided into numerous articulations
three or four times the length of the diameter in the upper portion of the
thread, but longer below. This unusual septation, as it appears to be,
was general throughout the gathering, but the threads bearing oogonia
were more rarely divided, but sufficiently so to remove any doubt as to
the threads being genuine threads of Vaucheria, which at first we must
confess to have doubted. The question which next arose was as to the
purpose for which this septation had taken place, and an answer sug-
gested itself in the collection of the cytioplasm into denser masses
towards the centre of the cell, with most evident differentiation into oval
bodies, resembling zoogonidia in course of formation. The time of
observation has been short, but long enough to raise a suspicion in our
minds that another form of fructification, by means of zoogonidia, takes
place in VavcJieria, and the occurrence of germinating spores in various
early stages in the water in which the Vaycheria was being preserved,
lends strength to this suspicion. It is quite true that Vaucheria haa
been often and patiently studied, and no intracellular swarm-spores
detected ; yet it maybe possible that, under certain conditions, they may
be produced. We are patiently waiting in hopes of obtaining active
zoogonidia.

8

120 SIPHOPHYCE^.

The plates for this part were all in course of printing when the above
observations were being made, so that it was too late to insert figures of
the septate threads and their contents.

Plate XLVL Figs. 1-20. Impregnation of Vaucheria sessilis after Pring-

sheim X 200.

Figs 1-4. Stages of development of sexual organs before impregnation.
Fig. 5. During impregnation. Figs. 6-8. The way in which the female
organ opens the cutaneous layer, bursts through, and a portion is con-
stricted off. Fig. 9. Approach of spermatozoids before formation of the
membrane of the embryo cell. Fig. 10. Point of female organ after
formation of the membrane of the true spore. Figs. 11-12. Later con-
ditions of spore after impregnation. Figs. 13-16. Male and female
organs after impregnation. Fig. 17. Colourless spore after it is detached
from the parent tube. Fig. 1 8. Detached spore, which after resting three
months has become green. Figs. 19-20. Germination of the green spores.

a. TuBULiGER-£. Antheridia little or scarcely bent.

1. Vaucheria dichotoma. Lyngb. Hydro. Dan. p. 75, t. 19.

Robust, loosely czespitose, dirty green, or becoming brownish.
Thallus very thick, setaceous, nearly a foot long, remotely
dichotomous. Oogonia sessile, globose, or ovoid, single, scat-
tered, or 2 to 4 to 6 approximating. Oospores, when mature,
with a triple membrane, spotted with brown. Antheridia single,
erect, oval, sub-clavate, or acute, on the same or on different
threads. — Rabh. Alg. Eur. in. 268.

SIZE. Oogonia •! mm. diam. Threads '2 mm. diam.

Walz in Pringsh. Jahrb. p. 152, t. xiv. f. 28-33. Fl.
Danica t. 1724. Harv. Man. p. 147. Grev. Br. Alg. p. 190.
Gray. AIT. i., 289. Kirsch. Alg. Schl. p. 82. Eng. Bot. ii., t.
2418. Grev. Fl. Ed. 305. Mack. Hib. 233. Fl. Devon ii.,
56. Kutz. Tab. vi., t. 56a. Hass. Alg. t. 4, f. 1. Eng. Fl. v.,
p. 319. Nordst. Bot. Not. 1879, p. 184. Jenner Fl. Tunb.
Wells, 176.

Conferva dichotoma, Linn. Spec. 1635. Dillw. Conf. t. 15.
Eng. Bot. t. 932. Huds. Fl. Ang. p. 593. Withering iv., p.
49. Hull Br. Flora, 330.

Vauclieria globifera, De Bary Monals. 1856, p. 589. Rabh.
Alg. Ex. No. 640.

Vaucheria salina, Kutz. Tab. vi., t. 66, f. 2.

Conferva Plinii setis porcinis, Ray. Syn. 58.

Conferva dichotoma setis porcinis, Dillen. Muse. 17, t. 3, f. 9.

var. /? sub marina. Ag. Syst. p. 171.
Vauclieria submarina, Berk. Glean, p. 24, t. 8. Harv. Phyc.
Brit. t. 350 B. Harv. Man. 147.

In ditches, and in brackish and salt water.

Hassell was of opinion that this species did not differ specifically from
Vaucheria sessilis, but the two are now regarded as belonging to different
sections. Nordstedt says that it is dioecious, but no reference is made to
this fact by Walz.

VAUCHERIACEJS. 121

Plate XLVI. fig. 21. Oogonia of Vaucheria dichotoma X 100 diara.
Fig. 22. Oogonium X 200. Fig. 23. Antheridea X 100. Fig. 24. An-
theridium X 200, after Woronin. Fig. 25. Germinating spore.

Plate J.LIX. Jigs. 5, 6. The V. submarina, Berk., generally referred
to this species as a variety.

2. Vaucheria aversa. Rass.Alg. t. 6, /. 5.

Loosely caBspitose, sparingly branched, expanding in all
directions, organs of fructification similar to those of V. sericea,
but with the thallus much thicker, the oogonia larger, and sub-
erect, now and then somewhat pedicellate ; oospores much
smaller.

Hass. Ann. Nat. Hist. xi. (1843), p. 429. Walz in
Prings. Jahrb. p. 151, t. 13, f. 25-27. Cleve. Vauch. 133, f. 7.

Vaucheria rostellata, Kutz. Tab. vi., t. 58, f. 4.

In ditches.

Hassall describes this species as " Capsules usually in pairs, and in the
form of a bird's head, with the beaks averted from each other. Sporangia
circular, not entirely filling the cavity of the capsule." To this he adds,
" It is one of the best marked, and most peculiar of the genus, the beaks
of the capsules being turned in opposite directions, at once distinguish it
from all other known species, in which, when the vesicles are in pairs,
they are directed towards each other. This averted position of the
capsules renders the existence of a distinct horn or anther essential for
each. In the form of the seed-vessels and in the circumstance of the
sporangia not filling the entire cavity, the species resembles V. or nit ho -
cephala " (now regarded as a variety of V. sessilis).

Plate XLVll.,fig. 1. Oogonia and antheridia of raucheria aversa X
100. Fig. 2. The same X 200. Fig. 3. Mature oospore in oogonium X
200, after Walz.

3. Vaucheria soricea. Lyng~b. Hydro. Dan. t. 21, B.

Tufts densely interwoven, yellowish, dirty green, or becoming
brownish ; thallus thin, loosely and vaguely branched ; oogonia
2 to 6 in a series, one sided, oblique oval, rostellate, inouth pro-
duced laterally, sessile or shortly pedicellate ; antheridia cylin-
drical, or rather clavate, horizontally deflexed. Spermatozoids
oblong, with a red spot, furnished with a cilium at each pole.

SIZE. Oogonia "1 mm. diam.

Walz in Prings. Jahrb. p. 150, t. xiii., f. 20-24.

Vaucheria ornitho cephala, Ag. Sp. Alg. p. 467. Grey. Alg.
Br. p. 193. Harv. Man. p. 148. Rabh. Alg. Exs. No. 1100.
Nordst. Bot. Not. 1879, p. 184.

Vaucheria polysperma, Hass. Ann. Nat. Hist. xi. (1843),
429. Hass. Alg. t. 6, f. 6. Kutz. Tab. vi., t. 58, f. 5. Rabh.
Alg. Exs. No. 1375. Cleve Vauch. p. 7.

In ditches, &c.

122 SIPHOPHYCE.E.

This is the I'aucheria polysperma of Hassall, who says of it : " It is by
no means uncommon, and may be distinguished from all others known
to me by the fineness of its filaments, which are not half so large as those
of our other British species, no less than by the form and arrangement of
the sporangia. These are slightly pedunculate, varying in number from
3 to 5, but usually there are but three, the apices or beaks of which are
neither turned towards or averted from each other, but are all directed
one way. The resemblance which the capsules bear to a bird's head
when viewed sideways is very remarkable, and this resemblance is
rendered still more striking by the fact that the circular sporangium
occupying only the central portion of each, and which therefore repre-
sents the eye of the bird. '

Plate XLVI1., Jig. 4. Oogouia and antheridia of V. sericea X
200. Fig. 5. Oogonia containing oospores x 200. Fig. 6. Mature
oospore enclosed in an oogonium X 200, after De Bary. Fig. 7. Zoospore
X 200, after Walz. Fig. 8. Spermatozoids.

b. CoRNicULATxE. Antheridia bent in the form of a horn or a
hook, seated on short lateral branches.

4. VauchexiaDillwyni. Ay.

Terrestrial, broadly expanded, forming a rather thin stratum,
of bright or dark green colour. Oogonia globose, or ellipsoid,
rostrate, sessile, usually single, sometimes in twins, enclosed in
delicately punctate membrane. Mature oospores spotted with
brown, sporoderm very thick, composed of several strata.
Antheridia bag-shaped, formed from the apices of short lateral
curved branches, either approximate to the oogonia or seated
between a pair of them.

Kabh. Alg. Eur. iii., 269. Grev. Alg. Britt. t. xix. Hass.
Alg. t. 4, f. 3. Eng. Fl. v., p. 320. Jenner Tunb. Wells 176.
Eng. Bot. ii., p. 124. Harv. Man. 147. Johnst. Fl. Berw. ii.,
251. Grev. Fl. Edin. 305. Mack. Hib. 234. Fl. Devon ii.,
56. Hook. Fl. Scot, ii., 93. Gray AIT. i., 290.

Vaucheria Ungen, Thnr. Ann. Sci. Nat. xix. (1843), t. 13, f.
43?

Vaucheria pachy derma, Walz Jahrb. p. 146, t. 12, f. 1-6.

Conferva frig ida, Dillw. Conf. t. 10. Harv. Man. p. 147.

Conferva amphibia fibriUosa et spongiosa, Ray. Syn. p. 59.

On the ground in damp shady places.

It is presumed that this is the same species as has been described by
Walz under the name of raucheria pachyderma, but the synonyms of some
of these species are a little mixed. Dillwyn says : " It is not unfrequently
found in turnip fields during the winter and early months of the spring,
particularly in a northern exposure, and on a cold soil. The patches
vary in size, but are usually two or three inches in extent, adhering but
slightly to the soil, and consisting of loose unconnected filaments."
" The form of the capsules, which are rarely pedunculated, will at once
distinguish this from all other species," says Hassall, " which have
hitherto been described."

VAUCHERIACE^E. 123

Plate XLV1I., figs. 9, 10. Oogonia and antheridia of V. Dillwyni x
200. Fig. 11. Oogonium of the same X 200. Fig. 12. Mature oospore
enclosed in membrane of oogonium X 230, after Walz. Fig. 13. Sper.
matozoids.

5. Vaucheria sessilis. Vauch. Conf. p. 81. pi. 2, /. 7.

Loosely intricate, pale or rather dull green. Thallus capil-
lary, sparingly branched ; oogonia 2 to 3 approximate, rarely
single, ovate or oblong-oval, more or less oblique, rostrate ;
antheridia intermediate, either short, hamate, or straight and
subulate, or a little clavate, sometimes elongated and in-
curved, rarely circinate. Mature oospores punctate with
brown, involved in a triple membrane.

SIZE. Oospore -07 mm. diam., thread -07 mm. (Cleve).

Eng. Fl. v., 320. Cleve Vauch. 133, f. 6. Kirsch Alg.
Schl. 82. Walz Vauch. p. 145. Kutz. Tab. vi., 59, f. 2.
Hass. Alg. t. 4,' f. 2. Eng. Bot. t. 1765. Harv. Man. p. 148.
Grev. Alg. Br. p. 192. Jenner Tunb. Wells 176.

Vaucheria splicer ocarp a, Kutz. Tab. vi., t. 59, f. 1.

Vaucheria racemosa, Rabh. Alg. Sachs. No. 495.

Vaucheria Ungeri, Thur. Ann. Sci. Nat. xix. (1843), t. 11,
12, 13, f. 37-42 and 44.

Sporangia. —

Vaucheria clavata, Vauch. Conf. t. 3, f. 10. Hass. Alg.
59, t. 2, f 20-33. Harv. Man. 149. Berk. Glean, t. 10.
Gray. AIT. i., 290.

In ditches, or on the ground.

var. a. caespitosa. Vauch. Conf. p. 26, t. 2, /. 4.

Oogonia usually in pairs, ovate, opposite. Antheridia in-
termediate, generally short, circinate.

Vaucheria ccespitosa, Garni. Eng. Fl. v., p. 321. Eng. Bot.
1, t. 2841, ii., t. 2421. Hook. Fl. Scot, ii., 92. Jenner
Tunb. Wells, 176. Grev. Alg. Britt. 194. Harv. Man. 148.
Johnst. Fl. Berw. ii., 251. Hull Br. Fl. 330. Abbot. Bedf.
275. Mack. Hib. 234. Gray Arr. i., 291.

Conferva amphibia, Dill. Conf. t. 41. With. Arr. iv., 129.
Ends. Fl. Aug. ii., 594. Lightf. Fl. Scot. 979. Sibth. Ox.
336.

Conferva amphibia fibrillosa et spongiosa, Dill. Muse. t. 4, f. 17.

Conferva terrestris exilis fibrillosa, Ray. Syn. 59.

On the margins of streams or pools.

" Fronds densely interwoven into cushion-like tufts or strata of in-
definite extent, irregularly branched, the tips erect, giving the surface, the
appearance of bright green velvet." — Harvey.

Dillwyn's description of his Conferva, amphibia seems to be most appli-
cable to this species. " On the edges of ditches, and in similar situations,
it frequently occurs in masses so densely matted as to hold water like a

124 SIPHOPHYCE.E.

sponge, with its surface beset by erect branches which give it a very
bristly appearance. In this state it is well known to botanists as the
C. amphibia of all modern authors. Its hue is of a bright green,
becoming ash-coloured with age. The root I have not been able to dis-
cover, and the entangled mode of its growth renders it impossible to
ascertain the length of the filaments. These are repeatedly divided with
distinct patent branches, which, as before mentioned, when the plant
grows in shallow water, so that some of them are exposed to the air, send
out patent ramuli, of a stunted growth, from being out of their proper
element, which by their erectness give the plant its bristly appearance;
yet at the same time, if whilst in this state the waters rise so as to over-
flow the plant, their length is gradually increased, and losing their erect
position they yield to the current, and become the Geranium ccespitosutn
of Roth ; and after having thus changed, if by the subsidence of the
waters the surface is again exposed to the air, the filaments, of course
disposed horizontally, give the plant a bristly appearance by again throw-
ing out erect patent ramuli."

var. oxnithocephala. Hassall Alg. t. 6, /. 4.

In dirty green tufts, densely imbricated, and becoming paler.
Thallus loosely branched. Oogonia solitary, or in pairs, oval-
oblong, obliquely rostrate, beaks truncate, antheridia cylindric-
subulate, incurved, interposed, usually exceeding in length the
diameter of the oogonia.

Vaucheria ornithocephala, Eng. Fl. v., 320. Harv. Man.
148. Hook. Fl. Scot, ii., 93. Eng. Bot. ii., p. 195. Grev.
Alg. Britt. 190. Grev. Fl. Ed. 306. Fl. Devon, ii., 56.
Gray Arr. i., 291.

Conferva vesicata, Dillw. Conf. t. 74.

In stagnant or slow-flowing water.

var. rep ens. Hassall Alg. t. 6, /. 7. Ann. Nat. Hist. XL, 430.

Terrestrial. Oogonia single, sessile, oblong or ovate, shortly
rostellate, mouth lateral, truncate. Antheridia solitary, next
the oogonium, cylindric-clavate, erect, inclined or curved,
scarcely longer than the oogonium.

On the naked ground.

It is on Vaucheria sessilis that Sir J. E. Smith says are found th
" Vesicles of the nature of galls, perhaps, inhabited by Muller's Cyclops
lupula" figured on plate 2419 of the second edition of English Botany.
Hassall states that the species is V. geminata, but this is accounted for
by the belief which was current in those days that V. geminata was the
summer form of V. sessilis. — See Eng. Bot. ed. n., p. 125.

Plate XLVI., figs. 1 to 20. Impregnation of Vauclieria sessilis, after
Pringsheim X 200.

Plate XLVIII., fig. 1, part of thread, with sexual organs, of V. sessilis.
Fig. 2, oogonia and antheridia X 200. Fig. 3, oogonia and antheridium
of the variety ccespitosa X 300. Fig. 4, oogonia and antheridium of the
terrestrial variety repens X 200. Fig. 5, threads bearing sporangia at the
tips slightly magnified.

VAUCHERIACE.E. 125

6. Vaucheria geminata. (Vauch.} Walz. Jahrb. p. 147, t. 12, f. 7-11.

Dark or dull green, in dense intricate tufts. Thallus capil-
lary, tough, dicliotomous. Oogonia two (rarely 1 or 3),
ovate or obovate, opposite, distinctly pedunculate. Antheridia
intermediate, subulate, more or less recurved. Mature oospore
spotted with brown, sporoclerm colourless, composed of three
strata. Sporangia on the same or a proper thallus, broadly
cup-shaped, truncate, and angularly horned.

SIZE. Oospore -11--12 x -18-'19 mm.

DCand. Fl. Fr. ii., 62. Hass. Alg. t. 3, f. 1. Cleve Vauch.
p. 6, f. 4. Kirsch. Alg. Schl. p. 83. Kutz. Tab. Phyc. vi.,
t. 59, f. 3. Eng. Fl. v., 320. Harv. Man. 148. Eng. Bot.
i., t. 1766, ii., t. 2420. Grev. Alg. Britt. p. 193, t. 19.
Purton Mid. Fl. ii., 611. Johnst. Fl. Berw. ii., 252. Grev.
Fl. Ed. 306. Fl. Devon, ii., 56. Gray AIT. i., 291.

Ectospenna geminata, Vauch. Conf. 29, t. 2, f. 5.

Vaucheria Dillwyni, Rabh. Alg. Sachs. No. 1078.

To this species we also refer the following as synonyms,
although usually referred to V. sessilis : —

Vaucheria ovoidea, Hass. Alg. 57, t. 5, f. 3.
Vaucheria ovata, Gray AIT. i., 289.

Ectosperma ovoidea, Huds. Fl. Aug. 954. Hook. Fl. Scot.
979. With. Arr. iv., 129.

In ponds and ditches.

/ racemosa.

Oogonia shortly pedunculate, 3 to 5 or more aggregated
in a corymbose manner. Antheridia single, scarcely longer
than the oogonia.

SIZE. Oospore -06--08 x -075--08 mm.

Vaucheria racemosa, Eng. Bot. ii., 126. Grev. Alg. Britt.
195. Harv. Man. 149. Grev. Fl. Ed. 306. Gray Arr. i.,
292. Hass. Alg. 56, t. 3, f. 2.

We have reproduced Hassall's figure of this form in which the antheri-
dium is considerably longer than the oogonia. Vaucher says, ''This
species is one of the most common, and is found in nearly all ditches,
principally in the spring. It is loaded with little bouquets manifest to
the unassisted sight, and which with the microscope seem to he formed of
a common peduncle, subdivided into pedicels, each of which carries on
its summit a spherical body in every way resembling the grains of other
ectosperms, but nearly half as small again. In the middle of this
bouquet is the horn, which, without doubt, performs the function of a
male flower, and which is here but a prolongation of the peduncle. The
number of grains varies from 5 to 7, but commonly 4 are met with."

It is of this species that Hassall says, " It is most frequently infested
with the curious parasite Cyclops Itt-pula of Muller, which occasions the
growth on the filaments of such extraordinary-looking appendages, in
the midst of which the parasite resides." This parasite, whatever it may
be, was the subject of a communication by Mr. A. Lister to the Essex
Field Club, July 22, 1882, and will be found in the " Proceedings " of the
Club (Vol. iii.).

126 SIPHOPHYCE.E.

Plate XLV111., Jigs. 6-7. Oogonia and antheridia of V. geminata X
200. Fig. 8, non-sexual spores of the same X 200, after Walz. Fig. 9,
mature oospore x 200.

Plate [XL2X., fig. 4, fruiting branch of the variety racemosa, after
Hassall.

7. Vaucheria hamata. (Vauch.) Walz. p. 148, t. xn./. 12-17.

Aquatic or terrestrial, tliallus rather ri^id, vaguely branched.
Oogonia usually single, ovate or ovate-hemisphaerical, seated
on a short segment of the divided stem, the other segment
elongated, curved, forming the antheridium. Mature oospores
involved in a sporoderm formed of four or more strata.

Cleve Vauch. p. 6. Hassall Alg. t. v., f. 1. Gray AIT. i.,
289.

Ectosperma hamata, Vauch. Conf. 26, t. 2, f. 2. Hass.
Ann. Nat. Hist. xi.,p. 439.

Vancheria hamulata, Kutz. Tab. Phyc. vi., t. 61, f. 2.

In ditches.

'Vaucher wrote of this species — " It differs from all others by the
manner in which it carries its grains. The peduncles which sustain them
are much elongated, and they bear at their extremity two little threads,
the one is recurved and receives the anther, the other is shorter and
straighter, and carries the grain.''

Plate XLVIII.,figs. 10, 11. Oogonia and antheridia of F. hamata X
200. Figs. 12, 13, mature oospores free from oogonia X 200. Fig. 14,
sporangium X 200.

8. Vaucheria terrestris. Lyngb. Hydro. Dan. p. 77, t. 21, f. A.

Densely interwoven in a thin bright emerald stratum.
Oogonia usually single, pedunculate, attached by the flattened
base at the back of the incumbent elongated curved antheri-
dium. Mature oospores enclosed in a hyaline colourless sporo-
derm composed of four strata, considerably inflated.

Eng. Flora v., 320. Grev. Alg. Britt. p. 191. Eng. Bot.
ii., p. 124. Jenner Tunb. Wells, 176. Harv. Man. 148.
Johnst. Fl. Berw. ii., 251. Mack. Hib. 234. Gray AIT. i.,
290. Hass. Alg. 53, t. 5, f. 2. Berk. Glean, t. 9. Walz.
Jahrb. p. 149, t. xiii., f. 18, 19. Babh. Alg. Eur. p. 270.
Cleve Vauch. 131, f. 1.

Ectosperma terrestris, Vauch. p. 27, t. 2, f. 3.

Vauclieria circinata, Kutz. Tab. vi., t. 60, fig. 2.

Forming patches on damp and clayey soil.

" Threads more straight and rigid than in V. Dilln-yni, forming a more
lax and less interwoven stratum, the summits of the little branches often
erect, and giving the whole a bristly appearance." — Greville.

Plate XLlX.figs. 1, 2. Oogonium and antheridium of V. terrestris X
200. Fig. 3, mature oospore of same, after Walz x 230.

Plate XLIX.,fig. 7. Oogonium of V.veliitina, Ag. (a marine species),
after Harvey X 200.

NEMATOPHYCE.E. 127

ORDER IV. NEMATOPHYCEJZ.

Mnlticellular algee, chloropliyllose, membranaceous or fila-
mentous, with or without branches. Vegetation either terminal,
limited or unlimited, forming an articulate thread, or in the
beginning terminal, and afterwards lateral, forming a mem-
branaceous thallus of a single stratum. Cell multiplication by
repeated division in one or two directions.

Propagation by oospores, or by zoogonidia.

Divided into the following families : —

A. Vegetation by division of the cells at first in one, and
afterwards in two directions, forming a membranaceous thallus.

FAMILY I. ULVACEJI. — Thallus membranaceous formed of one
stratum of cells, either plane or expanded, or tubular, or saccate.

B. Vegetation by division of the cells in one direction,
forming a cellular series or articulate thread.

FAMILY II. — SPH^EROPLE^E. — Articulate thread not branched,
articulations greatly elongated, cylindrical, multilocular, chloro-
phyll mass distributed in ring-like bands.

Propagation by resting spores, which, before germination,
break up into zoospores.

FAMILY III. CONFERVACE.E. — Articulate thread, simple or
branched, vegetative articulations cylindrical, fructiferous always
more or less swollen. Chlorophyllose mass effused, or parietal,
often more or less regularly spiral.

Propagation by macro- and micro -gonidia.

FAMILY IV. PITHOPHORACE.E. — Cladophora-like plants,
with terminal vegetation. Articulate threads branched.

o

Propagation by neutral, quiescent, cask-shaped spores
(agamo-hypnospores).

FAMILY V. (EDOGONIACE^E. — Articulate thread either
branched or not branched ; articulations short.

Propagation by oospores after sexual fecundation.

FAMILY VI. ULOTRICHE.E. — Articulate thread not branched,
sometimes laterally connate ; articulations short, at times very
short.

Propagation by macro- and micro -gonidia.

FAMILY VII. CHROOLEPID^E. — Aerial algaa. Articulate
thread branched, cell membrane firm, filled with an equally dis-
tributed oleaginous golden or reddish endochrome.

Propagation by zoogonidia.

FAMILY VIII. CHJSTOPHORE.E. — Aquatic alg£e. Articulate
thread dichotomously branched, ramnli sometimes aggregated in
a fasciculate or penicellate manner. Chlorophyllose mass
usually collected in transverse bands.

Propagation by zoogonidia. — liabh. Alg. Eur. in, 286.

T

128 NEMATOPHYCE.E.

FAMILY I. ULVAOE^B.

Thallus membranaceous, or foliaceous, rarely crustaceous,
formed of one stratum of cells, either expanded, or tubulose, or
vesiculose.

Propagation by zoogonidia, arising from a repeated division
of the cytioplasm. Zoogonidia oblong, furnished at one ex-
tremity with two or four cilia.

Sub-Family 1. PEASIOLE^I.

Thallus expanded and foliaceous, rarely crustaceous.

GENUS 54. FRASZOLA. Ag. (1821.)

Thallus membranaceous foliaceous, ascending or erect, more
or less cvispate, composed of angular cells, distributed in plane
areas ; base sometimes loosely fibrillose.

Vegetation by division of the cells in two directions.

Fxasiola crispa. Kutz. Tab. Plnjc. V. t. 40, /. 6.

Tufts more or less dense, often long and widely expanded,
dark green, soft and elastic. Thallus plicate crisped, of variable
form and size, often bullate ; cells arranged in distinct areolas,
or confluent, quadrate, or oblong-quadrangular, now and then
twice as long as the diameter ; angles more or less obtusely
rounded.

SIZE. Cells -005--009 mm. diam., or -008--013 mm. x
•003--005 mm.

Jessen Mon. Pras. t. 1, f. 10-16. Kabh. Alg. Eur. iii, 308.
Lagerstedt, Pras. p. 19.

Ulva crispa, Hass. Alg. t. 78, f. 12. Eng. Flora v., p. 312.
Eng. Bot. ed. i, 2754; ed. ii, 2406. Lightf. Fl. Scot. 972.
Harv. Man. 171. Grev. Fl. Edin. 299. Hook Fl. Scot, ii., 91.
Mack. Fl. Hib. 243. Hull Br. Fl. 309. Abbot. Fl. Bedf. 273.
Johnst. Fl. Berw. ii., 250. Jenner. Tunb. Wells 190.

Ulva lactuca y, Huds. Fl. Aug. p. 567. Dillen. Muse. t. 9,
f. 6.

Ulva terrestris, Gray. AIT. i., 344.

Tremella crispa, With. Arr. iv., 81.

On damp ground, rocks, &c.

Hassall unites this species and the next together in one, but his
example has not been followed by his successors.

Common on moist shady ground, especially near houses and walls,
sometimes on old thatched roofs. Fronds very much crowded, forming
a dense stratum, rather lying on the soil or medium than attached to it;
deep green, rounded, thin, tender, but not gelatinous, variously curled

ULVACEJi. 129

and folded. Quaternate granules beautifully arranged in squares, con-
tained in larger ones, and separated by parallel pellucid lines, the whole
compared by Agardh to the walks and parterres of a garden. Annual.
Found throughout the winter and early spring. — Eng. Bot. p. 111.

Plate L. fig. 1. Plants slightly magnified. Fig. 2, portion of a frond
X 400.

Pxasiola furfur ace a. Menegh. Cenni. p. 36.

Forming a furfuraceous stratum, more or less expanded, dark
green. Thallus about a line long and broad, dilated from the
short stem-like base into a fan-like lamina ; margin slightly
undulate and repand, often emarginate at the apex or lobed.
Cells angular, arranged in regular quadrate, or almost quadrate
areolas.

SIZE. Cells '014--016 X -004--006 mm.

Jessen, Mon. Pras. t. 2, f. 1-10. Kabh. Alg. Eur. iii., 309.
Lagerstedt Pras. p. 32.

Ulva furftiracea, Grev. Sc. Crypt. FL t. 265. Eng. Fl. v., p.
312. Harv. Man. 171. Eng. Bot. ed. ii., p. 112. Grev. Alg.
Britt. 176, t. 18. Mack. Fl. Hib. 244.

On damp walls and rocks.

" Fronds closely tufted, forming a vivid green stratum, a yard or more
in extent, two or three lines in length, erect, obovate, truncated, and
usually eroded at the top, tapering at the base into a longish claw ;
margin inflected , substance firm, and void of lubricity. Cells in fours.
It does not adhere to paper." — Garni,

Plate L. fig. 5. Fronds slightly magnified. Fig. 6, young frond X 400.
Fig. 7, lower portion of mature frond X 400.

Frasiola stipitata. Sulir. in Jessen Mon. t. 2, /. 11-16.

Stratum csespitose, expanded, dark green. Thallus of
variable form and size, commonly one to two lines, rarely four
lines long ; dilated upwards from a stem-like base (lanceolate,
obovate. obcordate, reniform, flabelliform, &c.), often truncate
at the apex ; margin slightly repand ; cells in the stem-like
base in series, in the upper part disposed in small regular
areolas.

SIZE. Cells -G05--007 mm.

Jessen, Prasiola p. 16, t. 2. Rabh. Alg. Eur. iii., 309.
Lagerstedt. Pras. p. 36, fig. 4.

On rocks by the sea, &c.

Jessen, in his monograph of this genus, gives figures of the fronds of
some Irish specimens of the above species, which he had seen and
examined. It is, on the faith of this, included here, although it appears
to be the most marine of any of the four.

Plate L. figs. 8. 9. Fronds of P. stipitata magnified 4 diam. Fig. 10,
young frond X 400. Fig. 11, part of mature frond X 400. All after
Jessen.

] 30 NEMATOPHYCEJE.

Pzasiola calophylla. (Spreng.) 31enegh. Cenni. p. 36.

Ca?spitose, dark green, crispate ; thallus 2-4 lines long,
narrow, linear, rather circinate, attenuated at the base into a
stem, truncate at the apex, now and then crenate; cells large,
arranged in longitudinal series.

SIZE. Cells -004--005 x -002--004 mm.

Jessen, Mon. Pras. t. 1, f. 1-3. Lagerstedt. Pras. p. 40.

Ulva calophylla, Hass. Alg. 298, t. 77, f. 1. Eng. Fl. v.,
312. Grev. Alg. Britt. p. 176. Eng. Bot. ed. ii., p. 112.
Harv. Man. 171. Johnst. Fl. Berw. ii., 251. Mack. Hib. 243.

Bangia calophylla, Carai. in Grev. S. Crypt. Fl. t. 220.

On damp stones, rocks, &c.

" Forms a bright green thin stratum. Frond minute, three or four
lines long, linear strap-shaped, obtnse, tapering at the base, or suddenly
contracted into a cylindrical stipes, much waved and curled, very
variable in breadth. Granules quaternate, closely covering the frond ;
set in longitudinal rows, of which two or more (sometimes half a dozen)
form the breadth of the frond ; interstices colourless." — Harvey.

Plate L. Jig. 3. Plant magnified slightly. Fig. 4, lower portion of frond
X400.

Sub-Family 2. ULVEJI.

Thallus membranaceous, vesiculose, or tubulose.

GENUS 55. ENTEROMORPHA. Link. (1820.)

Thallus membranaceous, tubular or utricle-shaped, fixed at
the base (usually at the first, but afterwards often free
swimming) ; composed of one stratum of cells, sometimes
branched, but rarely much branched.

Propagation by zoogonidia, produced by repeated division of
the cytioplasm, rostrate at one extremity, and furnished with
two cilia.

Enteromoirpha intestinalis. (Linn.) Link. Hor. Ber. (1820.)

Fronds simple, elongated, variable in form and size, usually
becoming more or less inflated, obtuse above, attenuated at the
base, pale green ; cells 3-5-6 angled.

SIZE. Cells -012--02 mm. diam.

Eng. Fl. v., p. 314. Jenner, Tunb. Wells 190. Eng. Bot.,
ed. ii., t. 2408. Hass. Alg. 303, t. 77, f. 2. Grev. Alg. Britt.
179. Harv. Man. 173. Mack. Fl. Hib. 242. Wyatt. Alg.
Exs., No. 80. Eabh. Alg. Ear. iii., 312.

Ulvamarina tululosa intestinorwnfiguram. Ray. Syn., 62.

Tremclla marina tubulosa, etc. Dillen. Muse., t. 9, f. 7.

Ulva intestinalis . Huds. Angl. 568. Light. Fl. Scot.
963. Relh. Cant. 443. Purt. Midi. Fl. ii., 617. Hook. Fl.

ULVACE^E. 131

Scot, ii., 91. Johnst. Fl. Benv. ii ., 249. Hull, Br. Fl. 311.
Abbot Fl. Bedf. 273. With. AIT. iv., 125.

Scytosiphon intestinalis. Gray, AIT. i., 315.

Enteromorplia lacustris. Hass. Trans. Linn. Soc.

Fistularia intestinalis. Grev. Fl. Edin. 300. Fl. Devon,
ii., 57.

In ditches, chiefly in brackish water.

This exceedingly variable species has many forms or varieties to which
names have been given, one of which by rupture of the apex, is funnel-
shaped (var. CornucopicB), others are more or less thread-like, and others
inflated and bullate. Root a minute scutate disc. Frond from a few
inches to one or more feet in length, and from a line to three or four
inches, or more, in diameter; tubular, obtuse, tapering at base to little
more than the diameter of hog's bristle, gradually becoming inflated
upwards, and in old age often swelling out into a large membranous
bag, which is variously cusped and curled. Sometimes the whole frond
is compressed and very much crisped ; substance thin and membranous,
but not gelatinous, not closely adhering to paper in drying. Colour
varying from a transparent yellowish green to a dull grass green; in old
age and decay fading to a dirty white. Under the microscope a portion
of the frond exhibits the appearance of a transparent membrane covered
with green unequal angular cells. — Harvey.

It occurs on the sea shore, in tidal rivers, and ditches connected with
them, whether salt, brackish, or freshwater, sometimes at a considerable
distance from, the sea. In this respect it differs from, Enteromorplia
compressa, which is nut found in fresh water, and has therefore no claim
to be inserted in the present work.

Plate LI. Jigs. 1, 2. Small fronds of Ent. intestinalis, natural size.
Fig. 3, the variety Cornucopia, nat. size. Fig. 4, cells X 400. Fig. 5,
zoogonidia.

'o*

GENUS 56. MONOSTROIKA. T/tur. (1854.)

Frond plane or saccate, simple or torn and lobate, composed
of one stratum of cells, cells somewhat rounded (sometimes
quaternate) immersed in a homogenous membrane. — Thuret,Note
sur la synonymie des Ulva, fyc.

This genus was formerly included in Ulra, from which it was separated
by Thuret. See also Monograph of Monostroma, by Prof. V. Wittrock.
The majority of species are marine.

Monostroma laceratum. Thur. Note sur Ulv.

Thallus membranaceous, at length free, thin and flaccid, pallid
green, of irregular form, rugose, margin plane and eroded, or
crisped (*04-'05 mm. thick) ; cells rounded, twin, ternate, or
quaternate, disposed loosely in the intercellular substance, in
transverse section of the thallus oval (•017-'023 mm. high),
chlorophyllose body central, of the same form as the cell, of
which it occupies about one-half. — Wittr. J/o/?. Monostr., p.
80,*. I,/ 2.

Plate LI., fig. 6. Portion of frond X 200. Fig. 7, section of frond
X 200 diam.

132 NEMATOPHYCE^.

RIonostroma Wittrockii. Born. Notes Alg. p. 176.

Thallus membranaceous, gelatinous, bright green (18 mill.)
oblong, pedicellate, at first saccate, then open at the summit,
margin becoming irregularly lobed. The adult plant becomes
sessile, and is attached by apart of its surface, when mature the
fronds are large (8 cent, diarn.), the lobes plicate, elongated
and rounded, cell angular, subquaternate, in section of thallus
rounded, chlorophyllose body occupying about half the cell.

In salt or brackish water.

Perhaps hardly claiming a place in this work, as it is more truly a
marine species.

Plate LL, fig. 8. Portion of a frond X 200. Fig. 9, 10, sections of
frond X 200. Fig. 11, zoogonidia X 300. Fig. 12, germinating X 200,
after Bornet.

Monostroma bullosum. Wittr. Mon., p. 28, is the Tetraspora
ballosa of this work, see j;. 16, plate vi., fig. 1.

FAMILY II. SPH^BROPLBAOEJB.

Threads simple, with terminal vegetation, very long, articu-
late, articulations cylindrical, by spurious septa nmltilocular.
Chlorophyllose mass distributed in annular bands, which enclose
from 3-7 starch vesicles.

Propagation by oospores after sexual fecundation, very
numerous in the cells, at first green, then red; enclosed in a
stellate sporoderm.

GENUS 57. SFHJEROPLSA. Ag. (1824.)

Characters the same as given above for the family, which
consists but of one genus.

The following is an abstract of a memoir on SphtBroplea annulina, by
Cohn (in the "Ann. des Sci. Nat.," 1856, p. 187), describing the process
of fructification : — " The structure of the resting-spores is very singular.
They are red spherical bodies, from one 120th to one 100th of a line in
diameter, and formed of two hyaline membranes, the interior of which
is intimately connected with its plastic contents, whilst the exterior is
loose and elegantly plaited. These plaits or folds are so arranged that
they meet at their two poles ; often, however, they are very irregular
in shape and direction, especially in the larger spores.

" In germination the resting-spores undergo several modifications. They
become granular and change to a dull brown red, and a more transparent
circle appears in their centre. Frequently the red matter changes to
green before the germination, and this change of colour is gradual,
proceeding from the circumference to the centre of tho cavity. At
length the whole of the plastic contents divides into two, then into four
or eight bodies, which burst the double envelope and disperse in the
water as so many zoospores.

SPHJIROPLEACE^E. 133

" The zoospores are of an elegant shape, but this is not more uniform
than their size or colour. Usually they are globular or shortly cylin-
drical bodies, from one 190th to one 150th of a line long, of a beautiful
cinnabar or carmine red, and furnished at one of their ends with a small
colourless bead bearing two long cilia. Some of them are larger,
pyriform or fusiform, and the result probably of the undivided con-
tents of a resting-spore. Some of the zoospores are two-coloured
— red towards the beak, and green throughout the other part, or
the two colours are variously disposed, the colourless bead or beak,
and the two cilia are invariably very distinct. The zoospores exhibit
a slow jerking movement during several hours. This movement
is often interrupted for several hours, when the whirling suddenly
recommences. When the zoospores break through the integument
within which they are formed, they are not enveloped in cellulose, but
already during their period of activity they begin to invest them-
selves with a thin elastic pellicle. At the time of their germination this
envelope thickens and lengthens in the form of a spindle, the two ends
soon tapering off into long tails, which even the enlarging body of the
zoospore itself separates farther and farther apart. The contents of this
germ-cell, at first homogeneous and finally granular, change during this
first growth. What is left of the red oil is quickly transformed into
chlorophyll, and the plantlet assumes a uniform green colour. Never-
theless one may perceive from the beginning a number of vacuoles, or
limpid, colourless droplets, in the midst of the protoplasm with which
they are filled, and between them the chlorophyll collects in rings more
or less distinct from each other. Soon large grains of starch appear in
these collections of green matter, so that the plantlet combines all the
characteristics of an adult cellule of the Sphceroplea, even before it has
exceeded a 13th of a line in length. The terminal tails have been
observed after the plantlet was more than half a line long. Growth
takes place in the middle, by the successive division of the older rings.
The contents of the adult threads presents the most beautiful appear-
ances. It consists of a colourless protoplasm, a green chlorophyll, a
watery liquid, and granules of starch ; the whole so disposed that the
liquid element forms large vacuoles in a row, like the pearls of a
necklet, and the diameter of which is nearly as great as that of the thread
itself. Often these vacuoles abut on each other, and seem to give birth
to partitions. In the spaces between the pairs of vacuoles the green
plasma and grains of starch crowd together, though the space is dis-
jointed by the innumerable small vacuoles they throw off.

" On approaching fructification the vacnoles multiply to such an
extent as to give the endochrome the appearance of a frothy mass, in
which the starch granules are ii-regularly scattered. Soon after the
starch granules assemble in pairs or threes or larger numbers, and
around these groups the green plasma becomes more plentiful, so that
in time they appear as so many equidistant cysts in the axis of the
thread. The greater part of the vacuoles having gradually disappeared,
the green clots assume a stellate appearance, connected by green
mucous rays or filaments. Between these star-like clots large vacuoles
are formed in pairs, which flatten so as to look like partitions, so that
each thread seems to be divided into numerous compartments.

" The green matter contained in these compartments then undergoes
modifications, and the mucous rays are gradually resorbed, the chloro-
phyll contracting meanwhile — sometimes to the right and sometimes to
the left. In a short time the colourless plasm collects around the chloro-
phyll in such a manner that the partitions disappear, and the whole
contents of the thread breaks up into a large number of free globular
masses, easily distinguished from, the ambient colourless mucilage, and
containing a certain quantity of irregularly distributed chlorophyll. These

134 NEMATOPHYCE.E.

are the young spores, which undergo a marvellous variety of transforma-
tions. At first they are contiguous, but as they contract they become
free, though variable in shape, and with their chlorophyll distributed in
a thousand different ways. Finally they become spherical and almost
completely filled with chlorophyll interspersed with some starch granules,
and covered with a thin, smooth layer of plastic matter, but not with a
cellulose membrane.

" Long before the foregoing process has taken place, the cell-wall
proper of the thread has undergone some peculiar chemical alterations,
all tending to its final dissolution to free the fully-developed spores.
Previous to this, however, little apertures are formed in it at certain
points, varying in diameter from one 500th to one 300th of a line.

" All the cellules of the same filament do not undergo the modifica-
tions described. In a large number of them the phenomena are quite
different, the green rings, interspersed with colourless vacuoles,
gradually change to a reddish yellow, and the grains of starch dis-
appear. Soon the coloured matter thus formed becomes granular, and
is finally broken up into innumerable rod-like corpuscles."

Thus the cycle is completed, and we need not pursue the abstract
further. Plate LII. will serve to illustrate the various changes.

Sphaeroplea annulina. {Roth.) Ag. Syst. p. 76.

Green, yellowish, brick-red, or scarlet, cells 8 to 10 or 20
times as long as broad, with 20 to 30 chlorophyllose rings in
each cell; spores at length densely seriate, rarely disposed
irregularly, at first green, afterwards olive-brown, and then
red.

SIZE. Threads '036-'07 mm. cliam., oospore '018-'036 mm.

Rabh. Alg. Eur. iii., p. 318. Rabh. Alg. ex. 309, 455, 147.
Cohn, in Acad. Borl. 1855, p. 335. Ann. des. Sci. Nat. 4 ser.
(1856) v., t. 12-13. Cienkowski, Bot. Zeit. (1855), p. 777.
Fresenius Bot. Zeit (1851), p. 241. Braun, Rejuvenescence
p. 164,271,281.

Conferva annulina, Roth. Cat. iii., p. 7.

In quarries, pits, or inundated fields.

Cohii has remar-ked that whereas most confervoid Algse vegetate by
repeated subdivision of the terminal cell, being at some time or other
attached by the base, the present has both extremities alike, and
neither of them rooting, moreover the vegetation is carried on by
sub-division of the central cells, so that the terminal cells remain the
oldest.

Plate Lll. fig. 1. Portion of filament of Sph&roplea annulina with
the green cytioplasm in rings X 400. Fig. 2, cells showing the forma-
tion of spermatozoids X 400 with escaped spermatozoids s below. Fig.
3, spores having acquired a globose form being fertilized by sperma-
tozoids. Fig. 5, spores in an earlier stage. Fig. 8, isolated spore with
spermatozoid attached. Fig. 6, mature spores, having acquired an
orange colour and stellate outline, the primary membrane is detached
X 400. Fig. 7, cells showing arrangement of mature spores X 300.
Fig. 4, resting spore in various stages ; a, mature ; b, divided into 2 ; c
and d, further subdivided. Fig. 9, zoogonidia X 400. Fig. 10, germina-
tion of zoogonidia X 400. All except Fig. 7 after Cohn.

CONFERVACEJS. 135

FAMILY III. OONFERVAOB^B.

Threads articulate, either simple or branched, vegetation
terminal, unlimited. Articulations more or less elongated,
rarely abbreviated, now and then shorter than the diameter,
cylindrical, rarely swollen. Cell membrane sometimes mani-
festly lamellose. Chlorophyllovse mass granulate, containing
starch granules, effused, parietal, or sometimes contracted in the
centre of the cell.

Vegetation by the repeated division of the primordial utricle
in one direction.

Propagation by zoogonidia.

GENUS 58. MICROS FOR A. Thur. (1851.)

Articulate thread simple. Chlorophyllose mass at first
parietal, afterwards contracted in the centre. All articulations
fertile.

Propagation by zoogonidia. Zoogonidia arising from a
simultaneous division of the cell contents, small, numerous,
ovate-elliptical, cuspidate and colourless at one end, usually
furnished with two, rarely 3 to 4, cilia, escaping by rupture of
the cell.

Microspora fugacissima. (Ag. Syst. p 43.)

Pale green, or yellowish green, articulations before division
4 to 5 times as long as their diameter, after division about 2 to
2-g- times as long, not constricted at the joints.

SIZE. Cells •0085-'01 mm. diani.

Eabh. Alg. Eur. iii., 321.

Conferva fugacissima, Grev. Fl. Ed. 317. Gray AIT. i., 310.
Kirsch. Alg. Schl. p. 80.

In ditches.

Plate LIII. fg. 1. Portions of threads of M. fugacissima X 300
diam.

XVXicrospoxa vulgaxis. Rahh. Alg. Eur. in., 321.

Bright green, articulations 2 to 3J times as long as the
diameter.

SIZE. Threads '012 mm. diameter.

Conferva bombycina incequalis, Kutz. Tab. iii., t. 44, f. 3.

Microspora bombycina, Thuret. Rech. p, 12.

Conferva vulgariSj Kirsch. Alg. Schl. p. 79.

In ditches and pools.

Plate LIII. Jig 2. Portions of threads of M. vulgaris X 300 diam.

W

136

XVXicKOSpora fioccosa. (Ag.) Thuret. RecJi. t. 17, /. 4-7.

Articulations before division about twice as long as the
diameter, after division about equal, or a little shorter, slightly
constricted at the joints.

SIZE. Threads -015--017 mm. diarn. (according to Kirschner
•0075 --01 mm. diam.).

Eabh. Alg. Eur. iii., 321. Thuret. Ann. Sci. Nat. 1850, t.
17, f. 4-5.

Conferva floccosa, Ag. Syst. p. 89. Kutz. Tab. iii., t. 43. f.
3. Eng. Fl. v., 351. Eng. Bot. ii., t. 2474. Harv. Man. 126.
Mack. Hib. 224. Gray AIT. i., 310. Kirsch. Alg. Schl. p. 79.

Lyngbya floccosa, Hass. Alg. 223, t. 60, f. 1-2. Jenner, Tunb.
Wells, 188.

Conferva fug acissima. Dill. Conf. Supp. t. B.

In stagnant water.

Plate LI II. Jiff. 3. a, I, portions of threads X 300 ; c, cells divided
across for the escape of zoogonidia X 300 ; d, zoogonidia.

GENUS 59. CONFERVA. (Linn.} Link. (1820.)

Articulate threads simple, articulations cylindrical. Chloro-
phyllose mass homogeneous or granulate, including starch
granules.

Vegetation by division in one direction.

Propagation unknown, (? by resting-spores which subse-
quently produce zoogonidia).

Kecently "Wille has declared his belief in the universality of resting-
spores in the whole genus Conferva,* although it is hardly clear what
is his conception of the limits of the genus. In a new species which he
has described under the name of Conferva WittrocJcii, he gives detailed
account of spore formation, which it is presumed may be accepted as a
type of what usually takes place.

" The chlorophyllaceous contents contract, and become rounded. The
colouring matter collects principally in the ends of the cells, so that the
substance in the middle appears almost colourless; but after the con-
traction of the cell contents the chlorophyllaceous portions of the
protoplasm draw nearer together, until at last they coalesce and form a
round or elliptical body within the mother cell ; they then begin to
surround themselves with a membrane, which later consists of two
distinct layers. The spores are generally set free by the filaments
resolving themselves into H shaped cells (in which the cell wall of each
cell has a transverse fissure in the middle of the transverse walls) ; the
spores then fall out. Sometimes they escape by the cell walls becoming
converted into mucilage, their layers becoming gradually indistinguish-
able. On first germinating, the size of the spores increases, as the
result of which the outer membrane bursts. The outer membrane
consists of two pieces with pointed ends, one being much larger than the

* Ofversigt af Kon. Vetensk Akad Porhandl. xxxviii (1881). " Journal of Eoyal
Microscopical Society," Dec., 1882, p. 836.

COKFERVACE.E. 137

other, and covering it like the lid of a box. Afterwards, through the
expansion of the inner membrane, the smaller piece of the outer mem-
brane gives way, and the inner membrane grows through the aperture
thus formed in the form of a tube. The development was not followed
further, but the writer considers it probable that zoospores are first
formed from the resting spores."

In Conferva bombycina, var. minor, either single cells swell up into a
barrel shape, or here and there the contiguous ends of two neighbouring
cells assume a club-like form. It is here that the largest part of the
Chlorophyllaceous protoplasm accumulates, and after this the swollen
end iB separated by a transverse wall from the longer narrow part of the
mother-cell. The wall of the swollen part thickens later. The author
considers these cells to be resting-spores, although he was not able to
observe their germination. Conferva, bombycinavax. genuinahas similar
resting-spores.

Three modes of formation of resting. spores of Oonfervacece have been
observed — (1) by rejuvenescence, and the formation of a new membrane
round the contracting contents ; (2) by the thickening of the membrane
of the mother-cell ; (3) by separation of a portion of the cell substance
to a swollen part of the mother-cell, and the thickening of the membrane
of this portion.

Conferva fontinalis. BerTt. Glean, t. 14, /. 1..

Bright green, attached ; articulations 6 to 10 times as long
as the diameter, slightly swollen, a little constricted at the
joints, starch granules single, scattered or seriate, cell-membrane
rather thick, homogeneous, when heated with sulphuric acid
swelling and distinctly lamellose.

SIZE. Threads -OIG-'OIS mm. diam.

Kutz. Tab. iii., t. 45, f. 4. Eabh. Alg. Ear. iii., 323. Kirsch.
Alg. Schl. p. 78.

Attached to grass, &c., in ditches.

" It covers rushes, grass, &c., with a short downy green coat, which is
very conspicuous in spring and summer." — Berkeley.

Plate LI11. jig. 6. Threads of C. fontinalis X 150. Fig. 7, por-
tions of threads X 400.

Conferva tenerrima. Kntz. Tab. in., t. 42, /. 1.

Usually pale green, articulations 1J-3 times as long as the
diameter.

SIZE. Threads '0035--004 mm. diam. (-003--005 mm.
Kirschner).

Rabh. Alg. Eur. iii., 322. Kirsch. Alg. Schl. p. 78.

In fresh water, often mixed with other Algaa.
Plate LIII., fig, 5. Portions of threads of C. tenerrima X 400.

Conferva bombycina. Ag. Syst.p. 83.

Yellowish green or green, soft, silky ; articulations oblong-
cylindrical, slightly constricted at the joints, before division
three times as long as the diameter, collapsing alternately when
dry.

138 SIPHOPHYCE^:.

SIZE. Threads '006 --012 mm. diam.

Rabh. Alg. Eur. iii., 323. Kutz. Tab. iii., t. 44, f. 1, 2.
Eng. Fl. v.,p. 351. Eng. Bot. ii., p. 159. Harv. Man. 126.
Mack. Hib. 224. Kirsch. Alg. Schl. p. 79.

Conferva sordida, Dillw. Conf., t. 60. Johnst. Fl. Berw. ii.,
254. ' Eng. Bot. i., t. 2303. Grev. Fl. Ed. 317. Gray Arr.
i., 310.

VesicuUfera bombycina, Jenner Fl. Tunb. Wells, 186.

In ditches, pools, &c., common.
Plate L1I1. jig. 4. Portions of threads of C. bomlycina X 400.

GENUS 60. CH-ffiTOMORPHA. Kutz. (1845.)
Articulate thread simple, nearly equally thick, fixed by a
discoid, or root-like divided base, lower articulations always
short, before division equal, or half as long again as the diameter,
after division shorter than the diameter, upper articulations more
or less elongated. Cell-membrane thick, firm, sub -cartilagi-
nous, manifestly lamellose. Cell contents green, becoming by
age parietal, continuous, finely granulate, containing a few
starch granules.

Propagation by zoogonidia.

Chiefly marine, a few in brackish water.

The lamination of the cell walls in this genus, and in Cladophora,
appeared to Braun to present some analogy to the rings in vascular
stems. He says, " The great number of layers which may be distin-
guished by suitable treatment in the cell membrane, even of plants of
short life (Cladophora, Botrydium, &c.), is not opposed to the assump-
tion that they are diurnal layers, and it is imaginable, under this
hypothesis, that bright and dull days, as well as the age of the cell, and
other circumstances, may effect important modifications in reference to
the formation of distinguishable layers."

Chaetomorpha litorea. (Harv.')

Rigid, green, crisp ate ; articulations before division one and
a-half times as long as the diameter, here and there swollen in
pairs and discoloured.

SIZE. Threads '16 mm. diam.

Rabh. Alg. Eur. iii., 327.

Conferva litorea, Harv. Man. p. 208. Phyc. Britt., t. 333.

Conferva linum, Harv. in Eng. Fl. v., 352. Wyatt, Alg.
Danm., No. 220.

In salt water ditches, and estuaries.

" Filaments 3-4 inches long or more, loosely bundled together in
prostrate or floating strata of considerable extent, and of a pale green
colour, becoming darker and duller as the season advances. Each fila-
ment is irregularly curled and twisted, and sometimes angularly bent.
The articulations are cylindrical, filled with a pale green watery endo-

CONFERVACEJ5. 139

chrome, and about once and a-half as long as broad, and here and there,
at irregulai intervals, two proximate articulations, longer and broader
than the rest, form together a spindle-shaped swelling, in which a dark-
coloured endochrome collects, the mass being darkest and densest where
the two cells touch each other. This looks like the commencement of
fructification, but I am unable to say whether a sporangium is ultimately
formed. These dark-coloured double cells are frequently so numerous
that they give the filaments, when examined with a pocket lens, a varie-
gated appearance. Substance membranaceous, and in drying the plant
scarcely adheres to paper." — Harvey.

Plate L1V. fig. 1. Portion of thread of Chcetomorpha litorea X 100
diam.

Chsetomorpha linum. (Roth.} Kutz. Tab. ill., t. 55, /. 3.

Rather rigid, dark green, or now and then yellowish green
and less rigid, lower articulations equal or almost equal in
length to their diameter, upper articulations, before division,
two or three times as long as the diameter, or even four times,
here and there swollen. Cell-membrane of the lower articula-
tions thick, distinctly lamellose. the upper ones thinner and
indistinctly lamellose, contracted at the joints.

SIZE. Threads '25 mm. thick.

Rabh. Alg. Eur. iii., 327. Harv. Phyc. Britt., t. 150, f. A.

Conferva linum, Ag. Syst. 97. Eng. Bot. ii., t. 2363.

Conferva capillaris, Huds. Fl. Ang., p. 598. Lightf. Fl.
Scot. 988. Dillw. Conf., t. 9.

Conferva crassa, Eng. Fl. v., 252. Mack. Fl. Heb. 225.

In brackish and salt water.

" Filaments from a few inches to several feet in length, twice as thick
as a hog's bristle, very much curled, rigid, crisp, and brittle, soon becom-
ing flaccid if exposed to the air ; lying in thick but not dense bundles,
of considerable length, disposed in strata, one above the other. Articu-
lations about as long as broad, filled with granular fluid, which in some
joints is more dense than in others. Eventually the joints divide in the
centre by a transverse line, and the mass separates, a new diaphragm is
then gradually formed, and finally a new joint. This species varies
much in colour, being sometimes of a pale, at other times a dark green,
and is very often mottled with dark and light green. Substance rigid-
membraneous, scarcely adhering to paper in drying." — Harvey.

Plate L1V. fig. 2. Portion of sterile thread of Clioetomorplia linum
X 100. Fig. 3, portion of fertile thread with zoogonidia X 100. Fig. 4,
zoogonidia X 300.

Chaetomorpha sutoxia. (Berk.}

Dark green, crispate, rather rigid, interwoven in lax tufts,
articulations one and a-half times as long as broad, after
division shorter than the diameter, cell-membrane thick, dis-
tinctly lamellose.

SIZE. Threads -01-'012 mm. diam.

Con/erva suton'a, Berk. Glean., t. 14, f. 3. Harv. Man.
128. Phyc. Britt., 1. 150, f. B.

In brackish ditches, estuaries, and salt water.

140 SIPHOPHYCEJ2.

.•

" Filaments several inches to a foot or more in length, as thick aa
hog's bristle, variously carved and twisted, forming extensive, loosely
packed bundles or strata which fill the pools in which they grow. .Arti-
culations once and a-half as long as broad, filled with a dark green fluid,
at length separating by a transverse medial line into two poi'tions, which
eventually become separate joints. Colour dark green, not variegated.
Substance rigid, not adhering to paper in drying." — Harvey.

Plate LIV. fig. 5. Portion of base of thread of Ch&tomorplia
sutoria X 100.

Chaetomorpha implexa. (Dell.) Kutz. Tab. in., t. 51, /. 3.

Pale or deep yellowish green, crispate, interwoven in lax
tufts, rather rigid, sometimes mucous, articulations before
division twice as long as the diameter ; cell-membrane rather
thick, indistinctly lamellose, after application of concentrated
sulphuric acid at first homogeneous, but after four hours' action
manifestly striate-lamellose.

SIZE. Threads, '04-'06 mm. diam.

Rabh. Alg. Eur. iii., 329.

Conferva implexa, Dillw. Conf., t. B. Ag. Syst. p. 91.

Conferva sutoria, Crouan, Fl. Fin.

In brackish and salt water.

" Filaments forming densely interwoven strata, or tufts among the
branches of other Algao. Joints even, in the same thread varying from
a little shorter than their breadth to about once and a-half as long.
Colour a dark grass green." — Harvey.^

Plate LIV. fg. 6. Portions of threads of Clicetomorplia implexa X
200.

GENUS 61. RHIZOCLONXU1K. Kiitz. (1843.)

Articulate thread the same as in Conferva, but distinctly
contorted, and forming by prolification of the cells short root-
like processes.

Propagation unknown.

Rhizoclonium Caspaxyi. Harv. PTiy. Britt., t. 354, B.

Filaments elongated, slender, decumbent, pale yellow green,
stratified, interwoven, curved here and there, and angularly bent,
at the angles emitting short root-like branches, which some-
times lengthen, and are filled with endochrome; articulations
2 to 6 times longer than broad, with narrow dissepiments and
granular endochrome.

SIZE. Threads -018--025 mm.

Rabh. Alg. Eur. iii., 330.

In brackish and salt water.

" Forming a thin web of a bright green colour and considerable extent.
Filaments elongate, gracefully curve! rather than twisted, interwoven,
here and there angularly bent. At the angle issues a root-like process,

CONFERVACE^E. 141

v

which sometimes consists of but a few empty cells, at other times
lengthens out into a branch. Cells in the same fleece very various, and
even in the same filament at different ages ; the full-grown cell seems to
be fully six times as long as its diameter; but short cells once and
a-half to twice as long as broad, which seem to be cells in process of
development, are commonly mixed with the long cells. All contain a
granular endochrome, the grains of very unequal size." — Harvey.

Plate LIV. fig. 7. Portions of thread of Rhizoclonium Casparyi
X 200 diam.

Rhizoclonium flavicans. Jury. Alg.

Threads soft, simple, extremely fine, matted, somewhat
crisped, at first uniform pale green, at length distinctly jointed ;
articulations once and a-half as long as broad, dotted ;
interstices pellucid.

SIZE. Threads '018 mm. diam.

Eabh. Alg. Eur. iii., 331.

Conferva arenicola, Berk. Glean, t. 13, f. 3. Harv. Man.
128. Harv. Phyc. Britt., t. 354 A.

At the mouths of rivers, and salt marshes.

" Creeping on the sandy margin of pools in a salt marsh periodically
flooded, forming a thin, soft, delicate, crisped web of a pale yellow green.
Threads extremely slender, flexuous, at first self-coloured, with a few
scattered dots, then with manifest dissepiments, and finally the granules
contract and form a distinctly defined mass of a darker green in the
centre, with pellucid interstices. Articulations one and a half times as long
as broad. When dry the articulations are alternately contracted.3' —
Berkeley.

Plate LIV. jig. 8. Portions of threads of Eliizocloninm flavicans
X 200 diam.

GENUS 62. CLADOPHORA. Kutz. (1843.)

Articulate thread variously branched, cell-membrane usually
thick, lamellose ; cell contents parietal.

Propagation by zoogonidia, arising from simultaneous and
multipartite division of the cell contents, moving actively
within the mother-cell, afterwards escaping by a lateral or
terminal opening, furnished with 2 or 4 vibratile cilia, after-
wards germinating without fecundation.

Many species are entirely marine, but some are fresh water. All are
disposed to considerable variation, and numerous varieties are named in
connection with each of the fresh water species. The following arrange-
ment of the species from Kabenhorst's Algae will be useful in their identi-
fication : —

I. Threads collected in tufts, more or less lax or intricate.
A. Tufts at first attached, afterwards free swimming,
a. Cell contents not spirally disposed,
t Fruiting cells not terminal.

* Cell- membrane even fracta.

** Cell-membrane plicato-striate . . crisjjata.

&

142 8IPHOPHYCE.E.

B. Tufts forthe whole life attached.

a. Cell contents disposed in lax spirals.

t Fruiting cells terminal or subterminal.
* Cell-membrane even.
0. Branches connate

at the base .... canalicularis.
00. Branches not connate

at the base glomerata.

** Cell-membrane plicate .... flavescens.

II. Threads radiating from a common centre, aggregated in a more or
less spongy globe cegagropila.

Cladophora fracta. (Dilku.) Kutz. Sp. Alg., p. 410.

Branches and branchlets sparse, divaricate, here and there
refracted, often secund, the lower laterally inserted. Cell
contents of the branches not spirally arranged, cell-membrane
now and then very thick. Fructiferous cells not terminal,
often in the middle of the branches or at their base.

SIZE. Threads *1 mm. diam.

Kutz. Tab. iii., t. 50. Kabh. Alg. Eur. iii., 334. Jenner
Fl. Tunb. Wells 186. Harv. Man. 134.

Conferva fracta, Eng. Fl. v. 356. Johns. Fl. Berw. ii., 254.
Eng. Bot. i., t. 2338, ii., t. 2492. Dillw. Conf., t. 14. Lyngb.
Hydr. Dan. t., 52. Grev. Fl. Ed. 318. Hook. Fl. Scot, ii., 82.
Mack Hib. 227. Fl. Devon ii., 52. Gray Arr. i., 304.

Conferva vagabunda, Huds. Fl. Ang. ii., 601. Lightf. Fl.
Scot. 990. With Arr. iv., 139.

Conferva marina trichoides, lance instar expansa, Ray. Syn.
60. Dillen. Muse. 30, t. 5, f. 32.

Cladophora crispata, Hass. Alg. 216.

In fresh and brackish water.

"At first forming loose tufts, which frequently become detached, and
the plant is more commonly found constituting floating strata, many
tufts entangled together in each floating mass. Filaments capillary
from six to eight or ten inches long, much, but very irregularly branched,
the branches distant, spreading at wide angles, or much divaricated,
either dichotomous or alternate, the lesser branches repeatedly forked,
with wide axils, and the ramuli which are few and very patent, com-
monly secund, sometimes alternate. Articulations three or four times
as long as broad, rarely six times as long, those of the upper branches
pretty uniformly thrice as long as their diameter, at first cylindrical,
then becoming pyriform, and when mature elliptical, when the branches
resemble strings of dark green beads. Dissepiments finally much con-
tracted. Colour at first a pleasant grass green, becoming darker and
duller as the plant advances in age. The endochrome is at first fluid,
but in the full grown articulations (which are in fact changed into
sporangia) it becomes distinctly granular, very dense, and of a dark
colour. In drying the plant adheres to paper, but not very firmly." —
Harvey.

Plate LV. fig. 1. Upper portion of filament of Cladophora fracta X
10 Fig. 2, portion, with fertile cell X 100 diam.

<JONFERVACE.E. 143

Cladophoia cxispata. (Roth.) Kutz. Tab iv., t. 40, /. 1.

Less coloured than the preceding, now and then dark green,
sometimes colourless ; branches and branchlets remote, some-
times secund, insertion (at least of the lower branches) apical,
articulations collapsing, cell contents (at least of the upper
branches) disposed in a lax spiral. Cell-uienibrane delicately
plicate-striate.

SIZE. Primary branches -022 mm. thick, ultimate branches
less than half that diameter, main thread '12 mm. diam.

Rabh. Alg. Eur. iii., 337.

Conferva crispata, Dillw. Conf. t. 93. Eng. Fl. v., 356.
Eng. Bot. i., t. 2350. Hary. Man. 133. Gray Arr. i., 304.
Eng. Bot. ii., t. 2420.

In pools.

" Filaments about a foot long, or more, densely entangled, rather
tough, destitute of gloss, curled and crisped, especially when old.
Articulations 4 or 5 times as long as broad ; by drying they become
elliptical and compressed alternately."

Plate LV. fig. 3. Upper portion of filament of Cladopliora crispata
X 10. Fig. 4, small portion of sterile thread X 100 diam.

Cladophora glomerata. (Linn.) Kutz. Tab. Phyc. iv.

Branches in the upper part of the primary thread, and
branchlets of the second and third order, usually fasciculate or
penicellate. The cell contents of the larger cells applied in a
net-like or somewhat spiral manner to the walls. Fructiferous
cells always terminal, with the lower cells sterile.

SIZE. Primary and secondary branches to *06 mm. diam.
3 to 6 times as long.

Rabh. Alg. Eur. iii., 339. Jenner Fl. Tnnb. Wells 186.

Conferva glomerata, Linn. Eng. Fl. v., 306. Lightf. Fl. Scot.
993. Dillw. Conf., t. 13. Huds. Fl. Aug. ii., 602. Eng.
Bot. i., t. 2192, ii., t. 2494. Hair. Man. 134. Part. Mid.
Fl. ii.,610. Johnst. Fl. Berw. ii., 255. Grey. Fl. Ed. 318.
Hook. Fl. Scot, ii., 82. Sibth. Ox. 337. Abbot. Fl. Bedf.
375. With Arr. iy., 140. Gray Arr. i., 306. Hass. Alg.
213, t.56,57, f. 1-2.

Conferva fontinalis ramosissima glomeratim congesta, Ray Syn.
59. Dillen. Muse. 28, t. 5, f. 31, A. B.

Microspora glomerata, Hass. Ann. Nat. Hist. xi.

In clear streams and rivulets, usually attached to stones.

"The whole plant is of a bright, shining green, very smooth, but not at
all viscid or gelatinous to the touch. The principal stems are several
inches long, sending out numerous capillary branches, which are variously
subdivided, and terminate ultimately in ranges of little short ramuli all

X

144 SIPHOPHYCE.E.

directed one way, which gives the plant a peculiar clustered or tuft-
like aspect. Articulations at least five times longer than they are broad."
— Eng. Bot.

Plate LVI. jig. 1. Portion of apex of thread slightly enlarged. Fig.
2, portion of branch X 100. Fig. 3, tip of branch with zoogoniclia X 200
diam. Fig. 4, zoogonidia X 320.

Cladophoxa flavescens. Ag. Syst. p. 112.

Pale yellowish, six inches long, very much branched, fascicu-
late in a plumose manner, branches patent, ultimate branchlets
often rather clavate, patent or incurved, cell-membrane often
distinctly plicate, cell contents distributed in a reticulate manner.

SIZE. Diameter of branches -07-'08 mm., 6-12 times as long.

Cladopliora glomerata, v. flavescens, Eabh. Alg. Eur. iii., 342.

Cladophora Jlavida, Kutz. Sp. Alg., p. 402.

Conferva flavescens, Eng. Fl. v., p. 356. Dillw. Conf. Supp.,
t. E. 'Harv. Man. 133. " Eng. Bot. i., t. 2088 ; ii., t. 2493 ;
Wyatt Alg. Damn., No. 224. Mack. Hib. 227. Gray Arr.
i., 304.

Conferva pinnatula, Dillw. Conf., t. 95.

In ditches or pools of brackish or fresh water.

" This species grows in continuous tufts, which, as they rise to the sur-
face, form extensive floating strata covering the pool. Filaments slender,
capillary, tangled together, irregularly branched ; the main thread some-
what dichotornous, with widely spreading axils, and often bent in an
angular manner first to one side then to the other ; the lateral branches
alternately divided, patent, with a few distant, scattered, alternate, or
secund ramuli. Articulations cylindrical, many times longer than broad,
filled with a pale, granular endochrome. Colour when young, a yellowish
green, becoming yellower in age, and at last almost golden. When dry
it has a silky appearance, and fades in the herbarium to a yellowish
white. Substance soft, membranous, but not strongly adhering to
paper." — Harvey.

Besides its pale green coloar it is readily distinguished from C. fracta
by the much longer articulations, and their less granular contents.

Plate LV. Jiff. 5. Upper portion of filament of Cladopliora

X 10. Fig. 6, portion of filament with fertile terminal cell X 100.
Fig, 7, apex of terminal cells, with zoogonidia escaping X 200.

Cladophoxa canalicularis. (Roth.} l£utz. Sp. 409.

Dichotomously or trichotomously branched, branches connate
at the base, often fasciculately branched above as in C. glome-
rata. Fructiferous cells terminal. Cell -membrane often thick,
now and then swollen. Cell contents arranged in very lax spirals.

SIZE. Lower branches '08-' 12 mm., 4-8 times as long.

Rabh. Alg Eur. iii., 342.

Alga in tubules aquam fontanam deducentibus, Dill. Muse.,
t. 4, f. 15.

Conferva canalicularis, Sibth. Ox., 336. Hall Br. Fl., 331.
Abbot Fl. Bedf. 274. With. Arr. iv., 129. Relh. Cant.
443. Huds. Fl. Angl. 593. Purton Midi. Fl. ii., 610.

CONFERVACE.E. 145

In ditches, pools, and other standing water.

Articulations four to eight times as long as their diameter, usually
bright green.

Plate LVI. Jig. 5. Part of branch of C. canalicularis X 100 diam.

Cladophora aegagropila . (Linn.) Kutz. Tab. III.

Dark green, threads rigid, very much branched, radiating
from a common centre, at length agglomerated into a very
dense, spongy globe. Ramuli erect, often quite obtuse, articula-
tions sometimes incrassated upwards, cell contents not arranged
in spirals, cell-membrane now and then thickened.

SIZE. Branches -04-'07 diam, 2-4 or even 12 times as long.

Rabh. Alg. Eur. iii., 343.

Conferva wgagropila, Linn. Dillw. Conf,, t. 87. Purl.
Mid. Fl. iii., p. 175. Eng. Bot. ii., 1377 ; ii., 2496. Harv.
Man. 134. Eng. Fl. v., 357. Huds. Fl. Ang. ii., 604. Mack.
Hib. 228. Hull Br. FL 332. Hook. Fl. Scot, ii., 82.
With. Arr. iv., 141.

Conferva globosa, Phil. Trans. Roy. Soc. xli., 498.

Conferva cegagropilaris, Gray Arr. i., 308.

Cladophora glomerata, Hass. Alg., p. 213 in part.

var. Brownii (Dillw.).
Rabh. Alg. Eur. iii., 345.

Conferva Brownii, Dillw. Conf. Syn., t. D. Harv. Man. 134.
Eng. Fl. v., 356. Wyatt Alg. Dan., No. 225. Mack. Fl. Hib.
228. Eng. Bot. 2879.

" This singular vegetable production is a native of Alpine lakes in many
parts of Europe, often lying in great abundance at the bottom of the
water, and occasionally only rising and floating on the surface. It has
been found in the lakes of the north of England, Wales, Scotland, and
the district of Connemara in Ireland, but is generally esteemed rare. In
size it varies from that of a small pea to three or four inches in dia-
meter, and its form is always nearly spherical. Internally the larger
specimens are hollow, without any nucleus, and when examined their
substance is found to consist of innumerable green, pellucid, repeatedly
branched filaments, firmly entangled together. The vesicles, when the
plant is recently taken from the water, are turgid with fluid, and nearly
cylindrical, being slightly swollen towards the apex, where the granular
matter of the endochrome seems chiefly collected as a green opaque
mass ; in the terminal vesicle, however, of each branch it assumes often
a dark brown hue and more solidity, probably becoming the medium of
reproduction, and escaping in the form of sporules. The elasticity of
the balls may be estimated by the fact of their having been used as pen-
wipers in the north of England. — Eng. Bot. 167.

Plate LVI. fig. 6. Threads of C. cegugropila, nat. size. Fig. 7, portion
of upper branch X 100 diam.

146

FAMILY IV. PITHOPHORA.CEJ3.

Chlorophylliferous Cladopliora-like Fresh-water Algfe, con-
sisting of celly formed by bipartition of the terminal cell, the
thallus having two distinct parts — (1) the cauloid part,
developed from the germinated spore upwards, propagative, and
almost always branched, the branches placed a little space
below the top of their supporting cells ; (2) the rhizoid part
developed from the germinated spore downwards, almost always
sterile and branchless, commonly unicellular. Spores neutral,
quiescent (agamo-hypnospores), generally cask-shaped, single,
formed bv division into two of the cauloid cells, of the chloro-

v

phyll filled, and commonly widened upper parts of these cells ;
in germinating, as a rule, dividing into two cells, the one
giving rise to the cauloid and the other to the rhizoid part
of the thallus. — Wittrock, Monograph of the Pitliophoracece,
p. 46.

For full details of this Family, consult Prof. V. B. Wittrock " On the
Development and Systematic Arrangement of the Pithophoracea3 " (pub-
lished in English). Upsal, 1877.

GENUS 63. PITHOPHORA. Wittr. (1877.)

Character the same as that of the family given above.

The formation of spores is effected in the following manner: — The
tipper part, ^-^ of the mother cell of the spore, is somewhat widened.
The chlorophyll-coloured protoplasm in the lowrer, not widened, part of
the cell then passes little by little into the upper and widened part, till it
is quite filled with chlorophyll-coloured protoplasm. A transversal cell
wall is then little by little formed just below the point where the
widened part of the cell commences. In this manner are formed one
lower cell containing but little protoplasm, almost devoid of chlorophyll,
the so-called subsporal cell, and one upper cell, rich in chlorophyll and
reproductive, the spore. Its shape is, as a rule, cask-like or cylindri-
cally cask-like. When the membrane of the spore has attained a not
inconsiderable increase in thickness the spore reposes some time befo-re
germinating, and consequently belongs to the class of spores which is
called hypnospores. With regard to its origin, it may be called an
agamo-spore, as being formed neutrally without any fecundation.
Formation of spores may take place in all the cells of the cauloid, in the
terminal as well as in the inclosed. As a rule it begins in the youngest,
i.e., the terminal cells ; afterwards proceeding downwards, or, in other
words, basipetally, in the principal filament as well as in the branches.
It is these spores which give origin by their germination to the course of
development already described. In this manner you will see one neutral
generation, forming hypnospores, follow upon another, in an uninter*
rupted series, without any metagenesis.

PITHOPHORACEuE. 147

The reproduction of individuals may, however, be effected also in another
way than by the formation of spores. Besides the specimens which
form spores, there are others which never do so. These, which are dis-
tinguished by a richer ramification, transform part of their cells into so-
called " prolific cells." A common vegetative cell grows richer in
chlorophyll coloured protoplasm and starch, and is thus made fit to form
a new individual. This the prolific cells do, when they have been made
free, by the destruction of the mother specimen, by forming a new speci-
men laterally near their top, in the same manner as a branch — and later
a system of branches — is formed by a cell in the fertile specimens. That
the specimens originated by prolific cells have the power of forming
spores is certain, as well as that specimens forming prolific cells may
have been originated by spores. I do not know with certainty whether
specimens forming prolific cells may have been originated by prolific
cells themselves, but it seems to me in no wise improbable. — Witt-
rock, 1. c.

Pithophora Kewensis. — Wittr. Hon. p. 52.

Principal filament of the cauloid part of the thallus, in fertile
specimens, on an average '059 m. thick, with solitary branches
of only one degree (rarely of two), spores single, partly enclosed,
partly terminal, the enclosed spores cask-shaped, but more
elongated, on an average '08 m. thick and '2 m. long, the
terminal spores cask-shaped, with the upper end conical and the
top somewhat rounded, on an average '088 mm. thick and '219
mm. long ; the rhizoid part of the thallus as a rule unicellular.

Wittr. Mon. Pithoph.'t. 1 f. 8, t. 2 f. 1-12; t. 3 f. 1-9;
t. 4f. 2-11; t. 5 f. 9 10.

In tank, Water-lily house, Kew Gardens. August.

This singular plant is thought by Wittrock to have been an importa-
tion from Brazil. It has not been seen in its original locality for two or
' three years.

Plate LVI, Jig. 8. Portion of spore-bearing filament x 20. Fig. 9,

portion of principal filament with spore formed at the apex of a short

branch, and another in process of formation in the principal filament

x 200. Fig. 10, a mature enclosed spore x 200. Fig. 1] , part of cell

from rooting portion of a sterile thread x 200. All after Wittrock,

148 NEMATOPHYCE^E.

FAMILY V. OEDOGONIACEJE.

Monoecious, or dioecious alga?. Filaments articulated, either
simple (CEdogoniuni) or branched (Bulbochcete). Basal cell
obovate-clavate, mostly lobately divided, or ending in a disc.

Propagation by zoospores, or by oospores after sexual fecunda-
tion. The zoospores formed singly in certain cells, broadly oval
or globose, transparent at one end, and furnished with a crown
of vibratile cilia. Oogonia single or in a chain (2 to 5) con-
tiguous to each other, more or less tumid, with a single oospore
in each, becoming reddish brown or yellowish when mature,
and then, before germination, dividing into (mostly 4)
zoospores.

Male plants, dwarf (nannandrous) and attached to the female
plants, or elongated (macrandrous) and similar to the female
filaments (often rather thinner). Spermatozoids produced in
abbreviated special cells (spermogonia).

GENUS 64. CEDOGONIUM. Link. (1820.)

Articulated filament simple, at first fixed, afterwards free
swimming. Cells marked with transverse stria* at one or other
extremity. Terminal cell sometimes elongated and setiform.
Either monoecious or dioecious ; when dioecious the male plants
either dwarf — produced from short cells of the female plants —
or elongated and independent.

Propagation by asexual zoospores, and by oospores sexually
fertilized.

For details of the structure and reproduction, consult " Brann on
Rejuvenescence" (Ray Society, 1853). " Pringsheim Jahrbucher"
(1857). " Quarterly Journal of Microscopical Science," vi. new series,
1866, p. 149. De Bary, " yEdogonium und Bulbochsete " (1854). Juranyi
in Pringsheim "Jahrbucher" (1873). Carter, in "Annals of Natural
History," 3 ser. i, p. 31. Vaupell, " Jagttagelser ov. befrugt. CEdogo-
nium" (1859). Wood, " Fresh Water Algaa of the United States " (1872).
Wittrock, " Prodrornus Monographic (Edogoniearuin " (1874).

The sterile filaments of CEdogonium resemble those of Ccnferva at a
casual glance, but are soon seen to be distinguished by transverse parallel
striaa at one or other extremity of many of the cells. These striae are
indications of the mode of cell increase (PI. LVII, fig. 5) which takes
place in the following manner: — When a cell has reached maturity, and
is about to divide, a little circular line is seen near its upper end.
Gradually the line widens, and it is seen that the wall of the mother
cell has divided all round, and the cell above is slowly raised by the
growth of the daughter cell, arising, as it were, out of the apex of its
parent cell, and carrying upwards the first streak or cap left by the

CEDOGONIACE.E. 149

breaking away of the wall of the mother cell. In this manner the new
cell soon attains a length equal to the one from whence it sprung (the
successive stages shown on Plate LVII, figs. 1 to 4). When the young
cell has matured it becomes in turn a mother cell, the splitting round is
repeated, a second streak or cap is carried upwards, and thus as many as
four, five, or six successive cells are formed, as indicated by the four,
five, or six striae or caps which may be counted at the apex of a cell. The
number of caps corresponding to the number of cells produced in this
manner consecutively immediately beneath the caps.

Asexual reproduction takes place by the formation of a single zoospore
in one of the cells of the filament (Plate LVII, fig. 15). It is of a globose
or somewhat ovate form, furnished near its apex with vibratile cilia (fig.
14). When mature it escapes by rupture or fissure of the mother cell,
moves about for awhile, then becomes attached by the ciliated end, and
ultimately developes into a young plant.

Sexual reproduction is varied in three ways. In the monoecious species
the oogoniuin is an inflated cell, more or less globose, enclosing a single
oospore of similar form. The oogonium is either perforated by a pore,
or splits round and opens with a lid or operculum. The same thread
bears above or below the oogonium very much shortened cells, in which
one or two active spermatozoids are produced. These escape when
mature, and fecundate the oospore through the perforation or opening of
the oogonium, after which they disappear, and the oospore ripens into a
perfect, fertile, resting spore.

In the dioecious species there are two modes of sexual reproduction.
In one group of species the males are dwarf, almost might be called
antheridia. The oogonia and oospores are the same as in the monoecious
species. In like manner there are also abbreviated cells in some other
part of the same thread, but these do not produce spermatozoids, but
androspores, small active ciliated bodies, which move about for a time,
and then attach themselves either upon or near the oogonia, grow into
the form of an inverted flask (figs. 8 to 10), being supported by a more or
less elongated stein, and constitute the dwarf male (nannandrous) plants,
the cells at the apex of which contain the spermatozoids, the upper cell
opening by a lid, or cap, to permit of the escape of its contents, which
fertilize the oospore as in the previous method.

The second group of dioecious species have male filaments, which in
all respects resemble the sterile females, except that they are usually a
little thinner. The female filaments produce only the oogonia.
The male filaments, in certain abbreviated cells, give origin
to the spermatozoids, which in due time escape and fertilize the
oospores of the female plants. Thus, in the first group, the dwarf males
are generated in certain privileged cells of the female plants, whilst in
the second group the male and female filaments are from the first dis-
tinct. The former are called nannandrous species, the latter macran-
drous.

The fertilized oospore becomes a resting spore, which ultimately
passes through the following stages : — Previous to germination the spore
has an egg-shaped figure ; the cell contents are densely crowded, and
composed of minute brownish-green granules, closely surrounded by a
distinct cell-membrane. Outside this membrane there is found besides
quite a distinct cell-membrane. Upon germination there are formed in
both membranes slit-like openings, whereupon the cell contents emerge,
surrounded by an extremely delicate hyaline covering. The cell contents
are composed not of one, but usually of four green masses, each sur-
rounded by its cell-membrane. Sometimes also as it appears, abnor-
m ally, the masses are two or three in number. The four cells which
proceed from germination possess an oval form, and their cell-membrane
is hyaline. After the contents of the spore have emerged there remains

150 NEMATOPHYCE^).

behind the outer membrane, enclosing the inner one. After the four
cells have remained some time enclosed in the hyaline covering, this
becomes resorbed subsequently, and the four cells lie still and motion-
less, but after the course of a short time the cells burst on one end by
means of an annular slit, and the apex, separated thereby from the
remainder of the cell-membrane, becomes elevated like a lid. Through
the cir-cular opening the cell contents now emerge, which at the part
turned towards the opening is colourless. This apex moves with
vigorous motion backwards and forwards, and after an hour the cell
contents, in the form of a zoospore, leave their place of detention, which
we now find to be a doubly-coloured cell-membrane. The little zoospore
wheels in a lively manner about with a circling movement, whereby the
colourless point becomes directed downwards. Its appearance is like
that of an ordinary zoospore, and, like it, possesses an oval form and a
lighter apex, furnished with cilia, which during the motion is always
directed forwards. After a time the movements become faint, and
finally cease. The cilia disappear, and the light end becomes elongated
into a root, which sometimes becomes an organ of attachment, quite
like that produced in the germination of the ordinary zoospores. The
rounded end of the germinating zoospore acquires a little point-like
apex. This growth becomes divided by a transverse septum, and a little
two-celled CEdogonium has originated. From each spore there are thus
derived, in general, four plants.

Plate LVI2. figs. 1-5. Stages in the formation of new cells — after
Pringsheim. Fig. 6, male cells of Bulbochfste crassa, with spermogonia.
Fig. 7, zoospore of (Edogonium — after Pringsheim. Figs. 8-10, develop-
ment of dwarf males — after De Bary. Fig. 11, spermogonia. Figs.
12.13, imgregnation of CEdogonium ciliatum — after Pringsheim. Fig. 14,
zoospore of CEdogonium rividare. Fig. 15, zoospore developing in its
mother-cell — after Pringsheim. Fig. 16, zoospore of Bulbochcete
setigera. Figs. 17-19, segmentation of resting spores of (Edogonium.
Fig. 20, oospore escaping from oogonium. Fig. 21, mature oospore of
JBulbochtete undergoing division. Fig. 22, four zoospores developed
.from the same. Fig. 23, sterile cells of (Edogonium Reinschii. All
magnified 400 diam.

The following is an arrangement of British species, on the basis of
Wittrock's " Monograph " :—

CEDOGONIUM.
Sect. 1. Species monoecious.

A. Oogonia always destitute of median processes.

a. Oospores globose or subglobose.

a Oogonia globose or subglobose.
CE. Petri, Wittr.
CE. cryptosporum, Wittr.
CE. curvum, Pringsh.
CE. cymatosporum, W. % N.
CE. minus, Wittr.
CE. vernale, Hass.
CE. crispum, Hass.
CE. Vaucherii, Le Cl.

/3 Oogonia elliptic or egg-shaped,
CE. urbicum, Wittr.

b, Oospores ellipsoid or egg-shaped,

CE. palndosum, Hass.

CEDOGONIACE^E. 151

B. Oogonia furnished with verticellate m edia/i processes .

a. Oospores snbglobose.

CE. Itzigsohnii, De By.

b. Oospores subellipsoid.

CE. excisum, Wittr. ${ Lund.

CE. Archerianum. Cke. (Pringsheimianum, Archer).

Sect. 2. Dioecious species.

Sub-Sect. 1. Species with dwarf males.

A. Species with dwarf males unicellular.

a. Oogonia furnished with verticellate processes in the

middle.

CE. platygynum, Wittr.

b. Oogonia always destitute of median processes.

a Oospores globose or subglobose.

CE. Kothii, Le Cl.
CE. Areschougii, Wittr.
CE. pluviale, Nord.
CE. undulatum (Breb,}.

CE. Beinschii, Royt
/3 Oospores subellipsoid.

None.

B. Species bicellular, spermogonia internal, with d?varf males.

CE. depressum, Prings.

C. Species mitli dwarf males bi-multicelltdar, spermogonia external.

a. Oospores even.

a Oospores globose or subglobose.

CE. flavescens, Hass.
CE. Braunii, Kutz.
CE. macrandum, Wittr.
CE. crassiusculum, Wittr.

/3 Oospores ellipsoid or egg-shaped.

CE. Borisianum, Le Cl.
CE. concatenatum, Sass.
CE. acrosporum, D. By.
CE. ciliatum, Hass.

b. Oospores echinulate.

a Oospores globose.

CE. Cleveanum, Wittr.
CE. echinospermnm, Br.

fi Ooospores ellipsoid.
None.

Sub-Sect. 2. Species dioscious, with elongated male plants,

a. Oospores echinulate.

None.

b. Oospores smooth.

a Oogonia not, or slightly, swollen.
CE. capillare, L.

152 NEMATOPHYCE.E.

/3 Oogonia manifestly tumid.

aa Oospores globose or subglobose.

CE. calcareum, Wittr.

CE. cardiacnm, Hass.

CE. carbonicum, Wittr.

CE. Pringsheimii, Cram.

CE. punctato-striatum, D. By.

/3/3 Oospores ellipsoid or egg-shaped.

CE. Boscii, Le Cl.

CE. tumidulum, Kutz.

CE. Lanclsboroughii, Hass.

v. gemelliparum, Pr.
CE. rivulare, Le Cl.

Sect. 3. Species of which the organs of fructification are imperfectly
known.

a. Oospores globose or subglobose.

CE. delicatulum. Kutz.
CE. tenellum. Kutz.
CE. hexagonum. Hass.
CE. Londinense. Wittr.
CE. fasciatum. Kutz.
CE. capillaceum. Kutz.
CE. Hutchinsise. Wittr.
CE. princeps. Hass.

b. Oospores subelliptic or oval.

CE. longatum. Kutz.
CE. vesicatum. Lyngb.
CE. grande. Kutz.
CE. giganteum. Kutz.
CE. crassum. Hass.
CE. subsetaceum. Kutz.

The following of Hassall's species of Vesiculifera have not been iden-
tified:—

Yesiculifera condensata, Hass. F. W. Alg. p. 196.
„ Cuvieri, Hass. F. W. Alg. p. 198.

Ralfsii, Hass. F. W. Alg. p. 199, t. 50, f. 8.

virescens, Hass. F. W. Alg. p. 200, t. 50, f. 5.

ovata, Hass. F. W. Alg. p. 20], t. 50, f. 6.

dissiliens, Hass. F. W. Alg. p. 202, t. 50, f. 7.

sphserica, Hass. F. W. Alg. p. 204, t. 53, f. 5.

ingequalis, Hass. F. W. Alg. p. 205, t. 53, f. 2.

dubia, Hass. F. W. Alg. p. 206, t. 53, f. 14.

Mulleri, Hass. F. W. Alg. p. 207, t. 53, f. 10,
„ alata, Hass. F. W. Alg. p. 208, t. 52, f. 9.

„ affinis, Hass. F. W. Alg. p. 206, t. 53, f. 1.

Some of Kutzing's species, which are imperfectly described, have been
mentioned as British, but we have no sufficient knowledge of them to
Warrant their insertion.

CEDOGONIACE^E. 153

SECTION 1. Monoecious species.
A. Oogonia always destitute of median processes.

a. Oospores globose or subglobose.
CEdogonium Fetri. Wittr. Mon. JEdog. p. 6.

Oogonia single, very rarely binate, pear-shaped globose, open-
ing by a pore a little above the middle. Oospores rather
depressed globose, almost filling the oogonium ; spermogonia
1-2 celled, hypogynous or epigynous ; spermatozoids single (?),
terminal cell obtuse.

SIZE. Cells -OOG-'OO? mm., 5-7 times as long; oogonia
•021--024 mm. x '022--029 mm.; oospore '020--23 x
•017--019 mm. ; cells of spermogonia -0055--006 x 'Ol-'Oll
mm.

Kirch. Alg. Schles. p. 51.

Ireland.

Having carefully measured a great number of the species here re-
corded, and found Wittrock's measurements universally accurate, we
have given his dimensions throughout for all the species recorded by him.
Unfortunately it is not easy to reduce Eabenhorst's measurements to
millemetres, and equally difficult to reconcile them.

Plate LX VIII. fig. 1. CEdogonium Petri with oogonia X "400.
CEdogonium ciryptopoirum. Wittr. Dispos. (Ed. p. 19.

Oogonia single, elliptic, or rather depressed globose, opening
by a median pore, almost rilling the oogonium, spermogoiiia 2-7
celled, scattered. Spermatozoids single (?).

SIZE. Cells -007-'009 mm. 4-6 times as long ; oogonia
•024--025 x '026--027 mm. ; oospore -022--023 X -019--021
mm.; cells of spermogonium -006-t)08 x 'OOT-'Oll mm.

var. )3. vulgare. Wittr.

Oogonia 2-5, continuous or single, spermogonia 1-4 celled, sub-
epigynous or hypogynous, or scattered.

SIZE. Cells -005--OOS mm. 3-5 times as long; oogonia
•018--025 X -018--026 mm. ; oospore -016--022 x -013--018
mm. ; cells of spermogonium -005--007 X '009--012 mm.

Kirch. Alg. Schles. p. 52. Wittr. Mon. p. 7.

Britain.

We have only seen the variety, from the West of England. The type
form has not yet been found in Britain.

Plate LXVI1I. fig. 2. CEdogonium cryptoporum. var. vulgare with
oogonia x '400

154 NEMATOPHYCE^E.

(Edogoniuxn curvum. Prings. Beitr. p 69, t. 5, /. 3.

Oogonia 2-7 continuous, or single, depressed globose, opening
by a median pore; oospores depressed globose, filling the
oogonium ; spermogonia 3 or many celled, situated in the upper
part of the filament ; spermatozoids single, the upper part of
the thread arcuate, or spirally twisted.

SIZE. Cells *005-'01 mm. 1^-4 times as long ; oogonia
•023--025 x •02-'024mm. ; oospore -02--023 x -016--019 mm. ;
cells of spermogonium -007--009 x '007--009 mm.

Wittr. Mon. CEdog p. 8. Kirch. Alg. Schles. p. 52. Rabh.
Alg. Eur. iii. 350.

Ireland.

Plate LV1II. Jig. 3. (Edogonium, curvum, with oogonia and spermo-
gonia x 400.

(Edogonium cymatosporum. Wittr. <$f JVord. in Wittr. disp.CEdoa.

p. 121.

Oogonia single, rarely binate, rather depressedly globose,
opening by a pore at the middle, or a little above the middle,
nearly filling the oogonium, membrane of the oospore scrobicu-
late (undulated in a transverse section), pits deep and dense;
spermogonia 1-4 celled, somewhat epigynous, hypogynous, or
scattered ; spermatozoids single.

SIZE. Cells 'OOS-'Ol mm. 4-7 times as long; oogonia
•024--034 x -027--036 mm. ; oospore -022--031 X -019--027
mm. ; cells of sperm. -008--009 x -009--015 mm.

Wittr. Mon. CEdog. p. 8.

Britain.

Plate LVIII. fig. 4. (Edogonium cymatosporum with oogonia. a
oospore vertical view x 400.

(Edogonium minus. Wittr. Mon. CEdog. p. 9.

Oogonia single, depressedly globose, manifestly splitting
round in the middle, opening by a median pore, oospores de-
pressedly globose, nearly filling the oogonium; spermogonia
1-10 celled, subepigynous, or subhypogynous, or rarely scat-
tered ; spermatozoids single ; vegetative cells slightly capitate,
membrane of vegetative cells and oogonia figured with dense
points spirally disposed.

SIZE. Cells -009--013 mm. 3-6 times as long ; oogonia
•034--046 x '028--042 mm.; oospore -03--042 x -026--036
mm. ; cells of sperm. -009--012 x '003-'005mm.

CEdog. punctato-striatum DeBary var. minor. Wittr. disp.
CEdog. Suec p. 123. Rabh. Alg. Eur. No. 2277.

Ireland.

Plate L VIII. fig. 5. (Edogonium minus with oogonia x 400.

CEDOGONIACE.E. 155

CEdogonium vernale. (Hass) Wittr. Man. (Edog.p. 10.

Oogonia single, obversely egg-shaped or globose, opening
with an operculum, fissure narrow, oospores globose, not filling
the oogonium, spermogonia bicellular, sub-epigynous.

SIZK. Cells -010-016 mm. by 4^-6 times as long ; oogonia
•339--045 x -045--051 mm. ; oospore '034--038 x '034--039
mm. ; sperm, cell -01--012 x 'OOS--009 mm.

Vesiculifera vernalis Hass. F. W. Alg. p. 434.

Vesiculifera Candollei Hass. F. W. Alg. p. 208, t. 52, f. 9.
Eabh. Alg. Ear. iii. 355.

England.

Plate LVI1I. fig. 6. (Edogonium vernale with oogonia and spermo-
gouia x 400.

CEdogonium ciispum. (Hass) Wittr. Non. CEdog.p. 10.

Oogonia single, obversely egg-shaped or globose, opening
with an operculum, fissure narrow; oospores nearly globose, not
filling the oogonium ; spermogonia 2-5 celled, hypogynous, or
sub-epigynous ; spermatozoids binate, terminal cell obtuse.

SIZE. Cells -01 2-'018 mm. 2-4-L times as long; oogonia
•037--049 x -042--054 mm. ; oospore -033--046 x '034--046
mm. ; sperm, cell -009--014 X '007--012 mm.

Kirch. Alg. Schles. p. 52.

Versiculifera cnspa, Hass. F. W. Alg. 203, t. 52, f. 8.

(Edogonium rostdlatum, Prings. Beitr. p. 69, t. 5, f. 1 ;
Archer Quart. Journ. Micr. Sci., 1867, p. 79 ; Rabh. Alg. Eur.
iii, 347.

CEdogonium pidchellum, Braun. Rabh. Alg. Eur. 2095.

Britain and Ireland.

" This is one of several monoecious species, but it is also characterized
by the oogonium not opening by a pore or aperture formed in its wall,
for the admission of the spermatozoids, as is usual in this genus, but by
a circuniscissile dehiscence. From the cleft so produced an inner mem-
brane projects, which seems to be itself perforate." — Archer.

Plate LVlIl.fig. 1. CEdogonium crispum with oogouia x 400.
CEdogonium Vauchexii. (Le Clerc.) JBraitn. Chytr, t. 2, /. 13.

Oogonia single, obversely egg-shaped, or globose, or nearly
globose, opening by a pore above the middle ; oospores globose
or nearly globose, not completely filling the oogonium ; spermo-
gonia 2-4 celled, sub-epigynous or hypogynous, spermatozoids
binate.

SIZE. Cells '02--03 mm. 1^-4 times as long; oogonia
•04--055 x -045--065 mm. ; oospore -035--05 x -035--052 mm. ;
sperm, cell -017--024 x -006--011 mm.

z

156 NEMATOPHYCEJE.

Wittr. Mon. QEdog., p. 13. Kirch. Alg. Schles, p. 52. Rabh.
Alg. Em*, lii., 349, in part.

Prolifera Vaucherii, Le Clerc sur. Prolif. 474, t. 24, f . 4 ?
Vesiculifera Vaucherii, Hassall, t 50, f. 4.

Britain.

Plate LVII1. Jig. 8. CEdogonium Vaucherii, with oogonia and
spermogonia x 400.

CEdogonium uxbicum. Wittr. Mon. (Edog. p. 13.

Oogonia single, ellipsoid, opening by a pore above the
middle, oospores globose, not filling the oogonium, spermogonia
visually 2 celled, spermatozoids binate, supporting cells destitute
of chlorophyll.

SIZE. Cells §016 mm. by 2|-, 6 times as long ; oospore
•033--045 x •033--045mm.

Kirch. Alg. Schles. p. 52.

CEdogonium tumidulum, Prings. Beitr., p. 69, t. 5, f. 2 (not
Kutzing). Micr. Journ. 1866, p. 69.

CEdogonium Vaucherii, in Rabh. Alg. Eur. iii., 349, in part.

Ireland.

Plate LIX. fig. 1. CEdogonium wlicum, with oogonium and spermo-
gonia x 400.

1). Oospores ellipsoid or egg-shaped.
CEdogonium paludosum. (Hass.~) Wittr. Mon. (Edog. p. 14.

Oogonia single, ellipsoid, usually rather oblique, opening by
a pore above the middle ; oospores ellipsoid, distinctly filling
the oogonium (membrane of the oospore, when mature, longi-
tudinally costate ?) ; spermogonia 1-8 celled, scattered, usually
situate in the upper portion of the filament ; spermatozoids
binate, often born with an oblique division.

SIZE. Cells -015-'02 mm. by 3-7 times as long; oogonia
•039--048 x -066--084 mm. ; oospore -036--045 x '054--063
mm. ; sperm, cell -Q14--016 x '006--013 mm.

Vesiculifera paludosa, Hass. F. W. Alg. p. 199, t. 52, f . 3 ?

England.

Plate LIX. fig. 2. CEdogonium paludosum with oogonium and spermo-
gonia x 400.

B. Oogonia furnished with verticillate median processes.

a. Oospores subglobose.
CEdogonium Xtzigsohnii. D'Bary (Edog. p. 56, t. 3, /. 29-32.

Oogonia single, ellipsoid, median processes 7-10, obtusely
conical, oogonia splitting round below the middle, opening by a

dEDOGONIACE^E. 157

pore in the fissure, viewed from above stellate, witli 7-10 rays,
the depressions between the rays deep and rounded ; oospores
globose, not filling the oogonium ; spermogonia 1-2 celled,
terminal cell obtuse or apiculate.

SIZE. Cells -008--01 mm. by 3-6 times as long ; oogonia
•034--03S x •032--04mm. ; oospore -022--023 X •022--023mm. ;
sperm, cell -008--009 x '009--015 mm.

Wittr. Mon. (Edog. p. 16. Kirch. Alg. Schles. p. 53.
Archer, in Quart. Journ. Micr. Sci., 1866, p. 63, Eabh. Alg.
Eur. iii., 352.

Ireland, Scotland.

This minute species Mr. Archer had found several times, and often
showing its pecnliarly-lobed oogonium, but he had never found the male
fructification ; he believed the plant must turn out to be a dioecious
species ; he had sometimes noticed a minute notch-like depression on
the upper outer margin of the oogonium, probably indicating the " micro -
pyle." He drew attention to the character, not adverted to by De Bary,
that the apical or terminal joint of the filament possessed a short acute
spine or macro. This in old plants, frequently is not to be seen, as the
terminal joint, or, indeed, considerable portions of the filaments, often
become detached, and chiefly in a young condition only are the plants
found entire. — Quart. Journ. I. c.

Plate L1X. fig. 3. (Edogonium Itzigsohnii, with oogonia and oospores;
#, transverse section of oospore x 400.

b. Oospores subellipsoid.

(Edogonium excisum. Wittr. 8f Lund., in Wittr. (Edog. Nov. p. 3,

t. I,/. 1-4.

Oogonia single, biconically-oblong, median processes 9,
rounded, small, oogonia deeply cut round (circumscissile),
vertical view orbicular, margin slightly undulated ; oospores
ellipsoid, as if constricted in the middle, not filling the
oogonium. Spermogonia 1-2 celled, subepigynous or hypo-
gynous, terminal cell obtuse, upper part of the filament curved.

SIZE. Cells -0035--005 mm. by 5-6 times as long; Oogonia
•013--015 x -018--025 mm.; oospore -009--012 x -015--018
mm. ; sperm cell -003--0035 x -006--007 mm.

Wittr. Mon. (Edog. p. 16. Archer, Quart. Journ. Micr.
Sci., 1875, xv., p. 102. '

Ireland (rare).

Plate LIX. fig, 4. (Edogonium excisum, with oogonia ; a, section of
oospore x 400.

(Edogonium Archerianum, CooJce.

Monoecious ; oospore elliptic, its wall marked by somewhat
coarse longitudinal ^trise, not filling the cavity of the much

158 NEMATOPHYCE^.

larger and elliptic oogonium; aperture of the oogoninm very
high up, being quite close to the annular striee of the caps.

(Edogonium Pringsheimianum, Archer, in Quart. Journ.
Micr. Sci., 1868, pp. 295.

Ireland.

There being already a species bearing the name of (Edogonium
Prinffsheimii, which had priority, it became necessary to alter Mr.
Archer's specific name. We have not seen the species, and hence are
unable to furnish a figure. Unfortunately 110 measurements are given
with the above very brief description, which is a doubtful economy of
space. It is the only monoecious species with striate elliptical
oospores.

SECTION n. Dioecious species.

i

A. Dwarf males unicellular.

a. Oogonia furnished with verticellate median processes.
(Edogonium platygynum. Wittr. (Edog. Nov. p. 1.

Gynandrosporous. Oogonia single (very rarely binate), de-
pressedly obverse egg-shaped, median processes 7-12, rounded;
oogonia cut round (circumscissile) below the middle, opening by
a pore seated in the fissure, vertical view -orbicular, margin
sinuate, \vith 7-12 (usually 8) depressions; oospores rather de-
pressedly globose, nearly filling the oogonium, androsporangia
1-3 celled; terminal cell obtuse. Dwarf males obverse egg-
shaped, small, seated on the oogonia.

SIZE. Cells -006-01 mm., from 2-5 times as long ; oogonia
•021--03 x •016-'024mm. ; oospore '017--024 x -015--02 mm. ;
androsp. cell -006--008 x '007--008 mm. ; dwarf males
•0045--005 x -0085--0095 mm.

Wittr. Mon. (Edog. p. 17, t. 1, f. 5-9. Kirch. Alg. Schles.
p. 53.

Ireland.

Plate L1X. fig- 5. CEdogonium platygynum, with oogonium ; a, trans-
verse section of oospore x 400.

b. Oogonia destitute of median processes.
a Oospores globose or subglobose.

(Edogonium Rothii. (Le Clerc.) Prings. Beitr. 69, t. 5, /. 4.

Gynandrosporous. Oogonia single, or 2-6 continuous, glo-
bose, or rather depressedly globose, opening with a pore at the
middle. Oospores rather depressedly globose, almost filling the
oogonia. Androsporangia 2-4 celled, subhypogynous ; dwarf
males obversely egg-shaped, seated on the oogonia.

SIZE. Cells -006--008 mm., 3-8 times as long ; oogonia
•02--021 x '016--019mm.

CEDOGONIACEJE. 159

Wittr. Mon. GEdog. p. 18. Kirch. Alg. Schl. p. 53. Rabh.
Alg. Ear. iii. 348.

Vesiculifera Rothii, Hassall, t. 53, f . 7 ?
Prolifera Rothii, Le Clerc Pro 1 if. 476, t. 23, f. 8 ?

Scotland, Ireland, England.

Mr. Archer mentions this plant as having been found by him with a
chain of as many as eleven oogonia in succession. — Quart. Micro. Journ.,
1861), p. 09.

Plate L1X. fig 6. (Edogonium Rothii with oogonia, androsporangia, and
dwarf males X 400.

CEdogonium Areschougii. Wittr. Lisp. (E.log.p. 122.

Gynandrosporous. Oogonia 2-6, continuous or single, rather
depressedly globose, broadly cut round (circnmscissile) in the
middle, opening by a pore in the fissure. Oospore exactly
globose, not by any means filling the oogonium. Androspo-
rangia 1-6 celled, hypogynous or snbepigynous, or rarely
scattered, terminal cell (which sometimesis the androsporangium),
obtuse, dwarf males obversely egg-shaped, seated on the oogonia.

SIZE. Cells -008--012 mm., 4-6 times as long ; Oogonia
•038--039 x -036--04 mm. ; oospore '022--024 X '022--024
mm.; audrosp. cells •Ol-'Ull X '01--012 mm.; dwarf males
•006--007 X -014--015 mm.

Archer in Quart. Journ. Micr. Sci. 1872, xii., p. 422. Wittr.
Mon. (Edog. p. 19.

Ireland.

Plate LIX. Jig 7. (Edogonium Areschougii with oogonia, andro-
sporangia, and dwarf males X 400 — after Wittrock.

(Edogonium pluviale. Nordst. Rab. Alg. Eitr. Nv. 2257.

Idio-androsporous. Oogonia simple, rarely 2-3 continuous,
obversely egg-shaped, globose, or nearly globose, opening by a
terminal operculum, fissure narrow ; oospores nearly globose,
almost filling the oogonium, terminal cell obtuse, filaments
bearing the androsporangia a little slenderer than the female
filaments ; androsporangia 6-10 celled ; dwarf males broadly
obverse egg-shaped, seated on the oogonia.

SIZE. Cells •018-'028 mm., equal to three times as long ;
oogonia -034--039 X -034--045 mm. ; oospore •032-<037x
•031--04 mm. ; androsp. cell -017--019 X '006--011 mm. ;
dwarf males -01 x '015 mm.

Wittr, Mon. CEdog. p. 19.

CEdogonium diplandrum, Jur. Beitr. (Edog. p. 27, t. 1-3.
Vesiculifera dissiliens, Hass. F. W. Alg. 202, t. 50, f. 7.

Plate LIX. Jig. 8. CEdogonium pluviale with oogonia and dwarf
male x 400.

160 NEMATOPHYCE^J.

(Edogonium undulatum. (Breb.) Br. in De Bary CEdog. p. 94-.

Oogonia single or twin, ellipsoid-globose, or nearly globose,
opening by a pore below the middle ; oospores ellipsoid-globose,
or nearly globose, nearly rilling the oogonia ; vegetative cells
four times undulatingly constricted ; terminal cell (which some-
times is the oogonium) obtuse ; dwarf males obconical, seated
on the supporting cells.

SIZE. Cells -015--017 mm., 3-5 times as long ; oogonia
•051--056 X -057--075 mm. ; oospores -046--05 X '04S--06
mm. ; dwarf males, -009--01 X '0.

Wittr. Mon. CEdog. p. 20. Kirch. Alg. Schles. p. 54.
Rabh. Alg. Eur. iii. 351.

Conferva undulata, Brebisson.

Cymatonema confervaceum, Kutz. Tab. iii., t. 47, f. 1.

Scotland.

Plate LIX. fig. 9. CEdogonium undulatum with oogonia and dwarf
male x 400.

(Edogonium Reinschii. Roy MSS.

Mr. Roy has announced that the Cymatonema figured by
Reinsch (Contrib. t. 6, /. 7) has been found in Scotland, and
is a genuine (Edogonium, but no further details have tran-
spired, and we know nothing of the fructification. The sterile
cells are figured on Plate LVII. fig. 23.

B. Dwarf males bicellular, spermogonia internal.

CEdogonium depressum. Prings. Beitr. 69, t. 5, /. 5

Gynandrosporous. Oogonia single, depressedly globose,
opening by a pore at the middle. Oospores depressedly
globose, not filling the oogonia ; androsporangia 2-celled ;
dwarf males oblong, obversely egg-shaped, one-third part
shorter than the oogonia on which they are seated.

SIZE. Cells >OOS-'OG9 mm., 3-6 times as long; oogonia
•028 X '026 mm. ; oospores -023 X '017 mm.

Wittr. Mon. (Edog. p. 21. Kirch. Alg. Schles. p. 54.
Rabh. Alg. Eur. iii. 349.

Vesiculifera cequale, Hassall, t. 53, f . 3 ?

Scotland.

Plate LX.Jig. 1. (Edogonium depressum with oosporangia, oospores,
dwarf males, and bicellular anclrosporaugia x 400.

C. Dwarf males bimulticeUular, spermogonia external.

a. Oospores with smooth membrane.

« Oospores globose or subglobose.

(Edogonium flavescens. (Hass.) Wittr. Disp. CEdog. p. 127
Idio-androsporous. Oogonia single, egg-shaped-globose

CEDOGONIACE^E. 161

(sometimes rather hexagonally globose), opening by a pore a
little above the middle ; oospores globose, not filling the
oogonia ; androsporangia 1-9 celled ; dwarf males a little
curved, seated on the supporting cell ; spermogonia 1 (or 2 ?)
celled.

SIZE. Cells '01S--021 mm. by 4J to 6 times as long;
oogonia -049--052 x -051--060 mm. ; oospore -045--049 x
•045--049 mm.; androsp. cell -017--02 x '008--018 mm.;
sperm, cells -009--01 X -015--02 mm.

Wittr. Mon. (Edog. p. 21, t. 1, f. 12-14.

Vesiculifera Jtavescens, Hass. F. W. Alg. 206, t. 53, f. 9.

Plate LX. fig. 2. (Edogonium Jlavescens with single and twin
oogonia; a, androsporangia x 400.

(Edogonium Braunii. Kutz. Sp. Alg. p. 366.

Gynandrosporous. Oogonia single, ellipsoid, globose, open-
ing with a pore at the middle ; oospores globose, not filling
the oogonia ; androsporangia 1-2 celled ; dwarf males a little
curved, seated about the oogonium, often on the supporting
cells ; spermogonia 1-celled.

SIZE. Cells -013--015 mm., 2-4 times as long ; oogonia,
•03--033 X -033--036 mm. ; oospore -027--029 x '027--029 mm. ;
androsp. cell -014--015 x '011--012 mm.; sperm, cell '005 x
•009 mm.

Prings. Beitr. p. 70, t. 5, f. 6. Wittr. Mon. (Edog. p. 22.
Kirch. Alg. Schles. p. 55. Archer in Quart. Journ. Micr.
Sci. 1866, p. 69. Rabh. Alg. Eur. iii. 349.

Britain, Ireland.

Plate LX fig. 3. (Edogonium Braunii with oogonia, oospores, and
dwarf males x 400.

(Edogonium macrandum. Wittr. Disp. (Edog. 130, t. I,/. 3-5.

Oogonia single or twin (rarely three), obversely egg-shaped
or globosely egg-shaped, opening by an operculum, with a very
narrow fissure ; oospores globose or egg-shaped globose, not
filling the oogonia; terminal cell very shortly apiculate ; dwarf
males very much curved, seated on the oogonia (stem some-
times 2-3 celled) ; spermogonia many (to 7) celled.

SIZE. Cells -015--016 mm., 3-5 times as long; oogonia
•036--04 x -043--054 mm. ; oospore -031--034 x -033--039 mm. ;
sperm, cell -009 mm.

Wittr. Mon. (Edog. p. 24; Archer Quart. Journ. Micr. Sci.
1875, xv., p. 413.

Ireland, Britain.

Plate LX. fig. 4. (Edogonium macrandum with oogonia and dwarf
males x 400. Fig. 4. a, dwarf males seated upon the oogonium — after
Wittrock.

162 NEMATOPHYCE^E.

(Edogonium crassiusculum. Wittr. Disp. (Edog. p. 132.

Gynandrosporous. Oogonia single, or twin, globose egg-
shaped or nearly globose, opening by a pore above the middle ;
oospores ellipsoid-globose or globose ; membrane very thick,
almost filling the oogonia ; androsporangia 2-5 celled ; dwarf
males nearly straight, seated on or about the supporting cells ;
spermogonia 1 (?) celled.

SIZE. Cells -027-*03 mm., 3J to 5 times as long ; oogonia
•054--06X-06--075 mm.; oospore '051--057 x -052--063 mm. ;
androsp. cells '026--028 x -01--018 mm.; sperm, cell -007--009
mm.

Wittr. Mon. (Edog. p. 24.

Epping Forest (1882).

We have only found this species once in pools on the Loughton side
of Epping Forest, but the very thick coat of the oospore is remarkably
distinct, combined with other characters, so as to render its determina-
tion certain.

Plate LX. jig. 5. (Edogonium crassiusculum with oogonium and
dwarf males j «, androsporangia ; o, mature oospore X 400.

b. Oospores ellipsoid or egg-shaped.
(Edogonium Borisianum. (Le Clerc.) Wittr. Disp. (Edog. p. 132.

Gynandrosporous (or idio-androsporous ?). Oogonia single
or twin, obversely egg-shaped, opening by a pore above the
middle ; oospores obversely egg-shaped, almost filling the
oogonia ; supporting cells swollen ; androsporangia 2 ? celled,
terminal cell (which sometimes is the oogonium) obtuse, dwarf
males a little curved, seated on the supporting cells ; spermo-
gonia unicellular.

SIZE. Cells -015--021 mm., 3-5 times as long ; supporting
cells -03-'033 mm., twice as long ; oogonia -045-'05 x *06-'075
mm.; oospore -04-'044 x <051-'054 mm.; androsp. cell '017-
•018 x '015--02 mm. ; sperm, cell -01 x '021 mm.

Wittr. Mon. (Edog., p. 25. Kirch. Alg. Schles. p, 55.

Prolifera Borisi'.ma, Le Clerc Prolif. 175, t. 23, f. 6.

(Edogonium apophysatum, Braun, in Kutz. Sp. Alg. p. 366.
Kutz. Tab. Phy. iii., t. 35, f. 5. Rabh. Alg. Ear. iii., 251.

(Edogonium setigemm, Vaup. lagt. (Edog. 17, t. 1. Archer
in Quart. Journ. Micr. Sci. 1866, p. 69.

Britain, Ireland.

See Mr. Archer's detailed account of this species in the place above
quoted.

Plate LX. Jig. 6 (Edogonium Borisianum, with oogonium and
thickened supporting cell bearing the dwarf males; a, androspore
x 400.

(EDOGONIACB^E. 163

(Edogonium concatenatum. (HassS) Wittr.Mon. (Edog. p. 25.

Gynandrosporous. Oogonia 2-6 continuous, or single, egg-
shaped, or quadrangularly ellipsoid, opening by a pore above the
middle ; oospores filling the oogonia, sporoderm delicately
porose ; supporting cell swollen; androsporangia 2-4 celled;
terminal cell obtuse, dwarf males curved, seated on the sup-
porting cells; spermogonia 2-4 celled.

SIZE. — Cells -025-'04 niin., 3-10 times as long; supporting
cells -058--062 mm., 2^ times as long ; oogonia -07--083 x
•09--105 nim. ; oospores -065--076' X 087--095 mm. ; androsp.
cell -027--028 x -03--036 mm.; sperm cell -013--015 x '022-
•025 mm.

Kirch. Alg. Schles. p. 55.

Vesiculifera concatenate*,, Hassall F. W. Algas t. 51, f. 6.

(Edogonium apophysatum, Pringsh. Beitr. p. 71, t. 5, f. 9.
Rabh. Alg. Eur. iii., 351, in part.

Britain.

Plate LJ.I.Jig, 1. (Edogonium concatenatum, with oogonium and
thickened supporting cell bearing the dwarf males ; a, androsporangia
x 400.

(Edogonium acrosporum. De Bary. (Edog. p. 60, t. 3, /. 1-12,

Idioandrosporous. Oogonia solitary, terminal, ellipsoid,
opening by a small apical deciduous (or evanescent) operculum ;
oospore manifestly filling the oogonia, membrane longitudinally
costate ; supporting cells often swollen, terminal cell obtuse;
dwarf males curved, seated on the supporting cells, stem often
bicellular, upper cells of the stem very long ; spermogonia 1-2
celled.

SIZE. — Cells '01-'014 mm., 2-7 times as long; supporting
cells '015-'018 mm., 2-3 times as long; oogonia '03-'035 x
•045--051 mm. ; sperm, cell -006--008 x -014--015 mm.

Archer in Quart. Journ. Micr. Sci. 1867, p. 80, 1868, p.
295. Wittr. Mon. (Edog. p. 16. Rabh. Alg. Eur. iii, 351.

Britain, Ireland.

The terminal oogonia are characteristic of this species, which can
scarcely be confounded with any other.

Plate LXI. fig. 2. (Edogonium acrosporum, with terminal oogonia,
after De Bary'x 400.

(Edogonium ciliatum. (Hass.} Prings. Beitr. 70, t . 5, /. 8.

Gynandrosporous. Oogonia 2-7, continuous or single, egg-
shaped, opening by an operculum, with a broad fissure ; oospores
egg-shaped, nearly filling the oogonia; androsporangia 2-8
celled, terminal cell setiform, dwarf males curved, seated on the
oogonium ; spermogonia unicellular.

2 A

164 NEMATOPHYCE^E.

SIZE. Cells •015-'023 mm., 2^ to 4 times as long; oogonia
•043--05 x -055--072 mm. ; oospore -04--046 x -047--057 mm. ;
androsp. cell -018--02 X -016--02 mm.; sperm, cell -008--01 x
•Ol-'Oll mm.

Wittr. Mon. GEdog. p. 27. Kirch. Alg. Schles. p. 56.
Rabh. Alg. Eur. iii., 347.

Vesiculifera ciliata, Hass. F. W. Alg*e 202, t. 52, f. 2.

(Edogonium piliferum, Aners. Rab. Alg. Sachs. No. 474.

Britain, Ireland.

Plate LXI. Jig. 3. (Edogonium ciliatum, with oogonia and dwarf
males ; a, androsporangia ; b, small plant (after Pringsheim) ; c, andro-
spore x 400.

b. Membrane of oospore echinulate. Oospores globose.
(Edogonium Cleveanum. Wittr. Disp.QSdog.p.129.

Gynandrosporous. Oogonia single, subglobose, opening by a
pore below the middle ; oospores almost filling the oogoninm,
globose, spirmlose, spines conical spirally disposed; andro-
sporangia 4-6 celled, dwarf males a little curved, seated on the
supporting cell ; spermogonia unicellular.

SIZE. Cells -018-'026 mm., 3-7 times as long ; oogonia
•052--06 x -059--063 mm.; oospores -049--057 x -051--059
mm.; spines -004 mm. long; androsp. cell '018-*022' x 009-
•018 mm.; sperm, cell '008--0085 x -014--016 mm.

Wittr. Mon. (Edog. p. 28. Kirch Alg. Schles. p. 56.

(Edogonium ecliinospermum, Pringsh. Beitr. 70, t. 5, f. 7.
Rabh. Alg. Eur. iii., 349, in part.

Ireland.

Plate LX1I. fig. 1. (Edogonium Cleveanum with oogonia, and
echinulate oospores ; «, androsporangia x 400.

(Edogonium echinospexmum. Br. in Kutz. Sp. Alg. 366.

Gynandrosporous, or idiandrosporous. Oogonia single,
ellipsoid-globose, or nearly globose, opening by a pore at the
middle; oospore almost filling the oogonia, globose, echinulate ;
spines awl-shaped ; androsporangia 2-5 celled, dwarf males a
little curved, seated on the supporting cells ; spermogonia
unicellular.

SIZE. Cells *018-'03 mm., 2-|-4l times as long ; oogonia
•04--05 X '042--057 mm. ; oospore -038--047 x -038--049 mm. ;
spines -003 mm. long; androsp. cell '021--025 x -009--015
mm. ; sperm, cell -01--012 x '012--015 mm.

Archer in Quart. Juurn. Micr. Sci. 1866, p. 69, 1867, pp.
80. Kutz. Tab. Phyc. iii., t. 36, f. 2. DBary (Edog. t. 3, f.
13-22. Wittr. Mon. (Edog. p. 29. Kirch. Alg. Schles. p. 56.
Rabh. Alg. Eur. iii., 349.

(EDOGONIACEJS. 165

Ireland, Scotland.

Of these two species with echinulate oospores, the spines of the
former are broader at the base and conical, whilst in this they are slender,
and but slightly thickened downwards.

Plate LX1I. fig. 2. (Edogonium echinospermum, with oogonia and
echinulate oospores x 400.

SUB-SECTION u. Dioecious, with elongated male plants.
Oogonia, not, or scarcely, swollen.

(Edogonium capillare. (Lin.) Kutz. Phyc. Gen. 225, t. 12,

/. 1-10.

Oogonia single, not swollen, cylindrical, opening by a pore
above the middle; oospores globose or cylindrical-globose
(somewhat quadrangular in longitudinal section) not filling the
oogonia ; male plants the same or almost the thickness of the
female plants ; spermogonia 1-4 celled, alternate with the
vegetative cells : spermatozoids binate.

SIZE. Cells -OSS-'OSo mm., equal or twice as long; oogonia
1^ times as long ; oospore '03-*052 x '039-'063 mm. ; sperni.
cell -03--048 x -005--OQ6 mm.

Kirch. Alg. Schles. p. 56. Rabh. Alg. Eur. NTo. 1180, 1417.
Wittr. Mon. (Edog. p. 30.

Conferva capillaris, Linn. Spec. PI. 1636.

CEdogonium regulare, Vaup. Beitr. (Edog. p. 213, t. 1, f.
1-10, not the Vesiculijera capillaris of Hassall.

Britain.
Plate LX1I. Jig. 3. (Edogonium capillare, with oogonia x 400.

b. Oospores manifestly swollen,
aa. Oospores globose, or nearly so.
(Edogonium calcaxeum. Cleve in Wittr. Disp. (Edog. p. 135.

Oogonia single (very rarely twin), depressedly globose,
opening by a pore at the middle ; oospores filling the oogonia,
male plants the same, or almost the same, thickness as the
female; spermogonia 2-5 celled; spermatozoids single (?).

SIZE. Cells >011-<014 mm., 2-4 times as long; oogonia
•027--03 x -021--023 mm. ; oospores -026--028 x -02--021
mm. ; sperm, cell 'Ol-'Oll x -009--012 mm.

Wittr. Mon. (Edog. p. 32.

Vesiculifera compressa, Hass. F. W. Algas, 204, t. 53, f. 4.

CEdogonium compresswn, Rabh. Alg. Eur. iii., 348.

Britain.

Specimens from the warm tank in the Victoria House, Kew Gardens,
had shorter cells than usual. It has apparently a tendency to become
more or less coated with a deposit of lime.

166 NEMATUPHYCE^E.

Plate LXII. Jig. 4. (Edoyonium calcareum, with portions of male
and female plants ; a, female plant from Victoria tank, Kew Gardens
x 400.

(Edogonium cardiacum (Hass}. Wittr. Disp. (Edog. 135.

Oogonia single, between heart-shaped and globose, opening'
by a pore a little above the middle; oospores globose, not fill-
ing the oogonia ; male plants a little slenderer than the female ;
spermogonia 2-10 celled ; spermatozoids binate, terminal cells
obtuse.

SIZE. Cells : fern. -018--03 mm. 2-7 times as long; cells :
male -015--025 mm. 2-6 times as long; oogonia -05--07 X
•058- 086 mm. ; oospore -04^--06 X §042-'06 mm. ; sperm, cell
•015--021 x -01--013 mm.

Wittr. Mon. (Edog. p. 33 ; Kirch. Alg. Schles. p. 57.

Vesiculifera cardiaca, Hass. F. W. Algse 203, t. 51, f. 4.

Vesiculifera pnlchella, Hass. F. W. Algte 199, t. 50, f. 3.

(Edogonium pulchellum, Rabh. Alg. Eur. iii. 356.

Britain.

Plate LXII. jig. 5. (Edogonium cardiacum, oogonia with oospores
x 400.

(Edogonium carbonicum. Wittr. Mon. (Edog. p. 74.

Oogonia single or twin, obversely egg-shaped — or ovate —
globose, opening by a pore above the middle; oospores ellipsoid-
globose or nearly globose, scarce filling the oogonia ; male plants
a little slenderer than the female ; spermogonia 2-5 celled ;
spermatozoids binate ; terminal cell obtuse.

SIZE. Cells: fern. '016--03 mm. 3-6 times as long ; cells:
male -014--016 mm. 3-6 times as long; oogonia '043-'052 x
•05--072 mm. ; oospore '042--05 x '046--056 mm. ; sperm, cell
•013--014X-012--014 mm.

Britain.

Plate LXIII. fig. 1. (Edogonium carbonicum with oospores. 1. a,
portion of male plant with spermogonia x 400.

(Edogonium Fzingsheimii. Cramer. Hedw. in. 17 t, 1 c, f. 1-4.

Oogonia single or 2-6 continuous, somewhat egg-shaped
globose, opening by an operculum, with a very narrow and
scarcely distinct fissure ; oospores globose, not distinctly filling
the oogonia ; male plants a little slenderer than the female ;
spermogonia 2-10 celled, alternate with the vegetative cells in
the upper part of the filament ; terminal cell obtuse or rarely
shortly apiculate.

SIZE. Cells : fern. •012-'02 mm. 2-4 times as long ; cells :
male •011-1016 mm. 2-4 times as long; oogonia -03-f043 x

CEDOGONIACE.E. 167

•036--045 mm. ; oospore -02S--035 X -028--034 mm. ; sperm,
cell -01--015 x -006--009 mm.

Kirch. Alg. Schles. p. 57 ; Rabli. Alg. iii. 348. Rabh. Alg.
Ear. No. 790; Wittr. Mon. (Edog. p. 33, t. 1, fig. 16-17.

CEdogonium Nordstedtii, Wittr. CEdog. Nov. 6, t. 1, f. 7-8.

Britain.

Plate LXIII. fig. 2. CEdogonium Pritigsheimii, with oogonia x 400.
(Edogonium punctato-striatum. De Bary CEdog. t. 2,f. 15-16.

Oogonia single, depressedlj globose, manifestly splitting
round (circumscissile) in the middle, opening by a pore in the
fissure ; oospore depressedlj globose, nearly filling the oogonia ;
male plants a little slenderer than the female ; spermogonia 3-7
celled; spermatozoids single; membrane of the vegetative cells
and of the oogonia spirally punctate ; basal cell depressedly glo-
bose ; membrane vertically plicate.

SIZE. Cells: fern. -018-'022 mm. 2-6 times as long; cells :
male 'OlG-'Ol^ mm. 2-6 times as long; oogonia >048-'05o x
•038-*048 mm.; oospore '044-'051 X '035--043 mm. ; sperm.
cell -016--018 X -006--01 mm.

Barker. P., in Quart. Jonr. Micr. Sci. 1871, p. 94 ; Rabh.
Alg. iii. 354. Rabh. Alg. Sachs. 214. Wittr. Mon. (Edog. p.
34. Rabh. Alg. Eur. No. 2276. Kirch. Alg. Schles. p. 57.

Ireland.

Distinguished by the cell wall being marked by spiral striae of a dotted
character, finely and closely set ; these seen in an empty cell, through
and through, the upper and lower striae being nearly in focus simul-
taneously produce a somewhat decussate appearance.

Plate LX1I1. fig. 3. CEdogonium punctato-striatum, with oogomum
x 400.

bb. Oospores ellipsoid or egg-shaped.
(Edogonium Boscii (Le Clerc}. Wittr. Lisp. CEdog. Suec.p. 136.

Oogonia single, rarely twin, oblong -ellipsoid, opening by a
pore above the middle ; oospores ellipsoid, by no means filling
the oogonia, longitudinally costate ; male plants the same or
nearly the thickness of the female ; spermogonia 3-6 celled ;
spermatozoids binate; terminal cell slender and somewhat
hyaline.

SIZE. Cells *014-'02 mm. 4-6 times as long; oogonia
•04--045 x -08--1 mm. ; oospore -036--04 x -06--065 mm. ; sperm,
cell •013--014X-006--009 mm.

Wittr. Mon. (Edog. p. 34. Rabh. Alg. Eur. iii. 357, Rabh,
Alg. Eur. No. 2198, 2369.

168 NEMATOPHYCE^E.

Vesiculifera Boscii, Hassall Algze t. 52, f. 3, 4, 5.
Prolifera Boscii, Le Clerc Prolif. 474, t. 23, f. 5.
Vesiculifera elegans, Hass. Ann. Nat. Hist.

England.

Plate LXT1I. fig. 4. (Edogonium Boscii, with oogonia x 400.
(Edogonium tumidulum. Kutz. Dec. Alg. No. 60.

Oogonia single, ellipsoid egg-shaped, opening by a pore above
the middle, almost filling the oogonium ; male plants a little
slenderer than the female ; spermogonia 6-45 celled ; eperma-
tozoids binate.

SIZE. Cells: fern. -018--025 mm. 3^-5 times as long;
cells : male -015-^018 mm. 4 times as long ; oogonia '056-'058
x -078--09 mm.; oospore -049--054 x '061-'068 mm.; sperm,
cell -015--017 x -009--012 mm.

Wittr. Mon. (Edog. p. 35. Kirch. Alg. Schles. p. 58 (not
of Pringsheim).

Ireland.

Plate LXIII. fig. 5. (Edogonium tumidulum with oogonium. 5 a,
portion of male plant with spermogouia x 400.

(Edogoniuxn Landsbozoughii (Hass). Wittr. Mon. (Edog. p. 35.

Oogonia single, rarely twin, obversely egg-shaped, opening
by a pore above the middle ; oospores obversely egg-shaped,
filling the oogonia (or rarely ellipsoid and not filling the
oogonia) ; male plants a little slenderer than the female ; sper-
mogonia 5-25 celled ; spermatozoids binate, with a vertical
division ; terminal cell obtuse.

SIZE. Cells : fern. '033-'036 mm. 4-6 times as long: cells :
male *031-'033 mm. 4-6 times as long ; oogonia '063--075 x
•1--12 mm. ; oospore -057-'07 X '075--1 nim. ; sperm, cell
•027--03X-009--012 mm.

Kirch. Alg. Schles. p. 58.

(Edogonium rivulare, Rabh. Alg. iii. p. 350, in part.

Vesiculifera Landsboronghii, Hassall, F. W. Alga3 t. 51, f. 2.

(Edogonium gemelliparum, Hantsch, Rab. Alg. Ear. 1118.

(Edogonium gemelliparum v. major, Wittr. Disp. (Edog. p.
137.

Britain.

Plate LX1V. fig. 1. (Edogonium Landsborougliii, with oogonia and
oospores x 400.

var j8. gemfellipamm (Prinys). Wiftr. Mon. (Edog. p. 36.

Smaller than the typical form. Oogonia egg-shaped; oospores
filling the oogonia ; terminal cell very long, somewhat hyaline.

CEDOGONIACE^E. 169

SIZE. Cells : fern. •Q2-1027 mm. 3-5 or 8 times as long ;
oogonia -055--057 x -075--OS mm.; oospore '049--051 x
•065--069 mm.

Kirch. Alg. Schles. p. 58. Archer in Quart. Journ. Micr.
Sci. 1866, p. 69.

(Edogonium gemelliparum, Pringsh. Beitr. p. 71.

Ireland.

Plate LXIV. fig. 2. (Edogonium Landsborottghii, variety gemelli-
parum, with oogonium x 400.

(Edogonium rivulare (Le Cle.rc). Braun, Cliytr.p. 23, t. I,/. 1-10.

Oogonia single, or 2-7 continuous, obversely egg-shaped,
opening by a pore above the middle; oospores obversely egg-
shaped, rarely ellipsoid or nearly globose, not by a long way
filling the oogonia ; male plants a little slenderer than the
female ; spermogonia 3-9 celled ; spermatozoids binate.

SIZE. Cells : fern. -045-'045 mm. 3-8 times as long; cells:
male -03--036 mm. 4 times as long ; oogonia '07-f085 x -13--16
mm. ; oospore -055-'07 X '065-' 1 mm. ; sperm, cell '021-'028 x
•014--016 mm.

Wittr. Mon. CEdog. p. 36. Kirch. Alg. Schles. p. 58.
Rabh. Alg. Eur. iii. 350 in part.

Prolifera rivularis, Le Clerc Prolif. 472, t. 23, f. 1.

Scotland.

Plate LXIV Jig. 3. (Edoyo?iium rivulare, with oogonium and oospore
x 400.

Species of which the organs of fructification are imperfectly

known.

a. Oospores globose or sub-globose.
(Edogonium delicatulum. Kutr. Tab. in., t. 33, /. 3.

Pallid, basal cell scarcely lobed at the base, affixed, cells
cylindrical; oogonia subglobose, inflated, a little extended at
either pole ; oospore perfectly globose.

SIZE. Cells I005-'006 mm., 3 times as long ; oogonia '02 x
•017 mm. ; oospores •012--014 mm.

Rabh. Alg. Eur. 355. Rabh. Alg. Ex. No. 1156.

Deeside (Scotland).

Plate LX VI. Jig. 7. (Edogonium delicatulum, with oogonia x 400.
(Edogonium tenellum. Kutz. Tab. in., t. 33, f. 9.

Basal cell two to three lobed, at first fixed, terminal joint
obtuse, cells cylindrical or rather clavate ; oogonia very much
inflated; oospore globose, bright orange.

170 NEMATOPHYCE.E.

SIZE. Cells -009--011 mm., 4-8 times as long ; oogonia
•025 mm. diam ; oospore !016--018 mm.
Rabh. Alg. Eur. iii., 355.

Dceside (Scotland).

Plate L~X.VI.fig. 6. (Edogonium tenellwn, with oogonia x 400.
(Edogonium hexagonum. Kutz. Tab. iu.,t. 35, /. 3.

Oogonia almost globose ; oospores globose, rufous-brown, not
filling the oogonia ; basal cell bifurcate ; terminal cell often
setigerous.

SIZE. Cells 'Oll-'OlS mm. 2-4 times as long ; oogonia
•025 x '025 mm.; oospore -016 mm.

Rabh. Alg. Eur. iii. 354.

Vesiculifera hexagona Hassall Algee t. 53, f. 11-12.

Deeside (Scotland).

Plate LXV1. Jig. 8. (Edogonium hexagonum, with oogonia x 400.
(Edogonium. Londinense. Wittr. Mon. Mdog. p. 39.

Monoecious? oogonia twin or single, globose, cut round (cir-
cumscissile) in the middle, opening by a pore seated in the
fissure ; oospores globose, almost filling the oogonia ; spermo-
gonia (or androsporangia ?) 1-2 celled, hypogynous.

SIZE. Cells '01-*015 mm. 1^ to 5 times as long ; oogonia
•033--035 x '033--043 mm. ; oospore -027--032 x -027-'032
mm. ; sperm, cells '026--027 X -027--029 mm.

England.

Plate LXV. fig. 4. (Edogonium Londinense with oogonia x 400.
(Edogonium fasciatum. Kutz. Tab. in., t. 34, /. 6.

Oogonia somewhat globose ; oospores globose, rufous-brown,
almost filling the oogonia ; basal cell usually bilobate, terminal
cell obtuse.

SIZE. Cells '028-'03 mm., twice as long ; oogonia '04 mm. ;
oospore '03--032 mm.

DeBary CEdog. t. 3, f. 23-28. Rabh. Alg. Eur. iii., 354.

Vesiculifera fasciata Hassall Algas t. 53, f. 6.

Deeside (Scotland).

Plate L XVI. fig. 2. (Edogonium fasciatum, with oogonia x *400.
(Edogonium capillaceum. Kutz. Phy. Gen. 255.

Dark green, basal cell attenuated downwards, bifid, terminal
point obtuse, cells sub-cylindrical ; oogonia broadly elliptical,
2-4 often contiguous, opening by a lateral pore ; oospore nearly

CEDOGONIACEJE. 171

globose, rufous-brown when mature, loosely involved in the
oogonium.

SIZE. Cells -02-'025 mm. 1^-3 times as long; oogonia
•05 X -04 mm. ; oospore -03-'032 nim.

Kutz. Tab. iii., t. 39, f. 6. Rabh. Alg. Eur. iii., 353.

Deeside (Scotland).
Plate LXVI. fig. 3. CEdogonium capillaceum, with oogonia x 400.

(Edogonium Hutchinsiae. Wittr. Mon. CEdog. p. 42.

Oogonia single, rather depressedly to somewhat egg-shaped
globose, opening by a pore above the middle ; oospores filling
the oogonium, epispore punctate with little warts ; supporting
cells swollen.

SIZE. Cells '03-'035 mm., 4-6 times as long; oogonia
•062--075 x -065--095 mm. ; oospores -06--073 x '055- -072
mm. ; supporting cells •04-'05 mrn. 2-4 times as long.

Ireland.

The figure is taken from original specimens from Miss Hiitchins in the
Royal Herbarium at Kew.

Plate LXV. fig. 1. (Edogonium Hut chin sice, with oogonia x 400.
CEdogonium princeps. (Hass). Wittr. Mon. (Edog. p. 42.

Oogonia single, somewhat egg-shaped globose, opening with
a pore above the middle ; oospores globose, not distinctly filling
the oogonium.

SIZE. Cells '037--045 mm. 1J-2J times as long ; oogonia
•061--075 x -068--08 mm. ; oospore -058--066 X -06--065
mm.

Vesiculifera princeps Hass. F. W. Alg. 195.

Vesiculifera capillaris Hass. F. W. Alg. 195, t. 50, f. 1-2.

England.

Plate LXV.fig. 2. (Edogonium princeps, with oogonia and (a) spermo-
gonia (?) x 400.

b. Oospores subelliptic or oval.
(Edogonium longatum. Kutz. Sp. Alg. p. 364.

Oogonia single (often solitary, terminal), rarely 2-3 con-
tinuous, ellipsoid, opening by an operculum, with a narrow
fissure ; oospores globosely-ellipsoid, scarcely filling the
oogonium ; terminal cell obtuse.

SIZE. Cells '005--006 mm. 2-3 times as long; oogonia
•016--017 x '021--024 mm. ; oospores -015--016 x -0175--0185
mm.

2 B

172 NEMATOPHYCE.E.

Kutz. Tab. Phy. iii., t. 33, f. 6. Wittr. Mon. (Edog. p. 38.
Britain.

Plate LXIV. fig. 4. (Edogonium longatum, parasitic upon another
Bpecies, with oogonia x 400.

(Edogonium vesicatum. (Lyngb.) Wittr. Mon. (Edog. p. 39.

Oogonia single, ellipsoid, globose, opening by an operculum,
with a narrow fissure ; oospores ellipsoid-globose, almost filling
the oogoninm.

SIZE. Cells '017--21 mm. 1^-3 times as long ; oogonia
•043--045 x '051--06 mm. ; oospore -037--038 X -041--042
mm.

Kirch. Alg. Schles. p. 59.

Conferva vesicata Lyngb. Hydro. 144, t. 47, f. D 1. Eng.
Bot. t. 2476.

Scotland.
Plate LXV. Jig. 5. (Edogonium vesicatum, with oogonium x 400.

(Edogonium grande. Kutz. Tab. Pliy. in, i. 37, /. 1.

Oogonia oval-elliptic, nearly twice as long as broad ; oospores
oval-elliptic, entirely filling the oogonia ; basal cell contracted
towards the base, then dilated and discoid ; terminal cell
obtuse.

SIZE. Cells -025- -035 mm. 3-4 or 5 times as long ; oogonia
•1 x '07 mm. ; oospore "09 x *OG5 mm.

DeBary (Edog. t. 2, f. 1-14. Rabli. Alg. Eur. iii., 353.

Scotland.

Plate LXVI. ng. 4. (Edogonium grande, with oogonium x 400.
(Edogonium giganteum. Kutz.Phyc. Germ. p. 200.

Oogonia single, a little swollen, cylindrically egg-shaped,
opening with a pore above the middle ; oospores cylindrically
ellipsoid, nearly filling the oogonia (sometimes flask-shaped,
short necked, and then filling the oogonia), epispore delicately
scrobiculate, supporting cells rather swollen.

SIZE. Cells '03--024 mm. 2-41 times as long ; supporting
cells '054--06 mm. H-lf times as long ; oogonia •057-'OG9 x
•078--106 mm. ; oospore '054--065 x -075--1U3 mm.

Kutz. Tab. Phyc. iii, t. 37, f. 2. Wittr. Mon. (Edog. p. 42.
Kirch. Alg. Schles. p. 59.

Vesiculifera lacustris Hass. F. W. Algaa 198, t. 52, f. 1.

(Edogonium lacustre Rabh. Alg. Eur. iii, 356.

Plate LXV. fig. 3. (Edogonium giganteum, with oogonia x 400.

(EDOGONIACE.E. 173

(Edogonium czassum. (Kass.~) Wittr. Gotl. Sotv. Alg. p. 20, t. 1.

/. 4-6.

Oogonia single (rarely twin), obversely egg-shaped ellipsoid,
a little swollen, opening by a pore above the middle ; oospores
ellipsoid, not filling the oogonia.

SIZE. — Cells -033--055 mm. 2-5 times as long ; oogonia
•065--07 x -1--125 mm. ; oospore '06--066 X 'OS-' 11 mm.

Wittr. Mon. (Edog. p. 43. Kirch. Alg. Schles. p. 59.

Vesiculifera crassa Hass. Alg. t. 51, f. 1.

Plate JjXVl. fig. 2. (Edogonium crassum, with oogonium x 400.
(Edogonium subgetaceum. Kutz. Spec. p. 368.

Basal cell dilated and discoid at the base, rather lobed,
terminal joint obtuse ; oospores broadly oval, golden red, closely
involved in the oogonium.

SIZE. Cells -04--052 mm. equal or twice as long ; oogonia
•065 x '055 mm. ; oospore '06 x -05 mm.

Kutz. Tab. iii, t. 41, f. 1. Kabh. Alg. Eur. iii, 352.

Deeside (Scotland).
Plate LXVI. fig. 5. (Edogonium subsetaceum, with oogonium x 400.

GENUS 65. BUX.BOCHCETE. Ag. (1817.)

Filaments articulated, branched, joints thickened upwards, at
or about the apex bearing seta?, which are straight, hyaline,
colourless, more or less elongated, bulbous at the base, cell
membrane usually punctate ; oogonia opening by a lateral pore
above the middle ; mature oospore red ; monoecious or
dioecious.

Reproduction sexual as in (Edogonium. In the dioecious
species nannandrous (dwarf males).

The following arrangement of the British species is based on that of
Prof. Wittrock :—

BULBOCHCETE.

Sect. 1. Oogonia globose or subglobose, patent ; oospores with the same
form, and filling the oogonia. Dioecious.

A. Dwarf males unicellular.

None.

B. Dwarf males licellular.

a. Basal cell of the stem of the male plants shorter than the
spermogonia.
B. intermedia, DBary.
B. polyandra, Cleve.
B. Brebissonii, Kutz.
B. setigera, Ag.

174 NEMATOPHYCE^.

&. Basal cell of the stem of the male plants longer than the
spermogonia.

B. gigantea, Prinff.

Sect. 2. Oogonia ellipsoid or snbellipsoid ; oospores of the same form,
filling the oogonia, epispore longitudinally costate, costae more or less
crenulate.
Sub-Sect. 1. Species monoecious.

B. mirabilis, Wittr.
Sub-Sect. 2. Species dioecious.

A. Dissepiment of supporting cell obsolete.

B. pygmcea, Pring.

B. Dissepiment of sup} oriing cell present.

B. insignis, Prings.
B. rectangalaris, Wittr.

Species of which the organs of fructification are imperfectly known.
B. gracilis, Prings.

SECTION!. Oogonia globose, or subglobose ; dioecious.

B. Dwarf males biceUular.
Bulbochoete intermedia. DeBary CEdog. 72, i. 4, /. 1-7.

Oogonia somewhat depressedly globose, seated beneath the
androsporangia, dissepiment of the supporting cell in the
middle ; epispore delicately crenulate (rarely seen) ; andro-
sporangia 1-2 celled, epigynous, rarely scattered, dwarf males
seated on the oogonia, stem slightly curved.

SIZE. Cells •017-*019 mm. 1^-3 times as long ; androspore
cells -013 X-01 mm. ; oogonia '04--048 X •031--04mm. ; dwarf
males -009--01 X -024--026 mm.

Wittr. Mon. (Edog. p. 44, t. 1, f. 18. Kirch. Alg. Schles.
p. 60. Rabh. Alg. Ear. iii, 358.

Britain, Ireland.

Plate LXVII. Jig. 1. SulbocJioete intermedia, with oogonia, after
DeBary x 400.

Bulbochoete polyandra. Cleve. Wittr. Disp. p. 140.

Idio-androsporous. Oogonia sub-depressedly globose, seated
beneath terminal setaa or vegetative cells ; dissepiment of sup-
porting cell above, or rarely about the middle ; epispore deli-
cately crenulate or nearly even ; androsporangia 4-10 celled ;
dwarf males seated on the oogonia, stem a little curved.

SIZE. Cells *015-*02 mm., 3-5 times as long; oogonia
•035--046 X -032--038 mm. ; androspore cell -013--014 x
•012--015 mm. ; dwarf males '008--009 X -023 mm.

Wittr. Mon. (Edog. p. 46, t. 1, f. 19, 20. Kirch. Alg. Schles,
p. 61.

Britain, Ireland.

Plate LXVII. jig. 2. Bulbochoete polyandra, with oogonia ; 2a, with
androsporangia x 400.

CEDOGONIACE^. 175

Bulbochcete Brebissoiaii. Kutz. lab. Phyc. iv, 19, t. 86.

Oogonia obcordate-globose, truncate below, erect, seated
beneath terminal setas or androsporangia, dissepiment of sup-
porting cell low, epispore delicately crenulate ; androsporangia
2-3 celled, scattered or epigynous ; dwarf males seated on the
oogonia, rarely around it, stem straight, or nearly so.

SIZE. Cells -017- '02 mm. by 3-4J times as long; andro-
spore cells '015 x -015--018 mm.; oogonia '042--05 x
•037--045 mm. ; dwarf males °01-'012 x -028--033 mm.

Wittr. Mon. (Edog. p. 46. Rabh. Alg. Ear. Exs. 1055.
Rabh. Alg. Eur. iii. 359.

Ireland.

Plate LJ.V1I. fig,. 3. Bulbochosle Brebissonii, with oogonia, and dwarf
males x 400.

Bulbochcete setigera. Ag. Syn. Alg. Scan. p. 71.

Oogonia depressedly, somewhat quadrangularly globose,
seated beneath terminal setae, or beneath androsporangia ; mem-
brane of the oogonium after fertilisation thickened ; dissepiment
of supporting cell a little above the middle, or at the middle ;
epispore granulated ; androsporangia scattered or epigynous,
bicellular; dwarf males seated upon or about the oogonia, stem
straight.

SIZE. Cells '025-'028 mm., 2J-5 times as long ; andro-
spore cells -018--02 X '014--018 mm. ; oogonia -075--08 X
•U6--065 mm. ; dwarf males, -012--013 X '034--036 mm.

Wittr. Mon. (Edog. p. 47. Prings. Beitr. 72, t. 6, f. 3.
Kirch. Alg. Schles. p. 61. Rabh. Alg. Eur. iii., p. 358. Hass.
Alg. t. 54, f. 1-4. Eng. Bot. ii. t. 2472. Eng. Fl. v, p. 350.

Conferva vivipara Dillw. Conf. t. 59. Eng. Bot. i, 2086.

Bulbochaete Rothii Gray. Arr. 1, 321 (?).

Britain, Ireland.

Plate XLVIIL fig. 1. Bulbochcete setigera, with oogonia and dwarf
males ; a, b, c, development of young plants x 400.

Bulbochcete gigantea. Prings. Beitr. 71, t. 6,/. 1.

Idio-androsporous? Oogonia rather depressed obcordate-
globose, seated beneath terminal setas, rarely beneath vegetative
cells ; dissepiment of supporting cell at or a little above the
middle ; epispore verrucose ; dwarf males a little longer than
the oogonia, and seated upon it ; stem twice as long as the
spermogonium, arcuate.

SIZE. Cells '024--027 mm. by 2-3 times as long ; oogonia
•062--066 x -051--058mm. ; stem of dwarf males -011--012 X
•04--045 mm. ; sperm, cell -013--OU x '02--022 mm.

176 NEMATOPHYCE^.

Wittr. Mon. CEdog. p. 48. Kirch. Alg. Schles. p. 61.
Rabh. Alg. Eur. iii., p. 357. Quart. Journ. Micr. Sci., 1866,
p. 276.

Britain, Ireland.

Plate L XVI II. Jig. 4. Bulbochcete gigantea, with oogonium and
dwarf male x 400.

SECTION 2. Oogonia ellipsoid or subellipsoid.

SUB-SECTION 1. Species monoecious.
Bulbochoete mixabilis. Wittr. Disp. CEdog. 137, t. I,/. 8, 9.

Oogonia ellipsoid, or rather oblong-ellipsoid, patent, or rarely
erect, seated beneath terminal setse or vegetative cells ; sperrno-
gonia 2-4 celled, erect (rarely patent), subepigynous, or
scattered.

SIZE. Cells '016-'02 mm. l^-lf times as long ; oogonia
•027--035 x -046--056 mm. ; sperm, cell -01--012 x -Q07--009
mm.

Wittr. Mon. CEdog. p. 50.

Britain, Ireland.

Plate L XV III. fig. 2. Bulbochcete mirabilis, with oogonia and
androsporangia x 400.

SUB-SECTION 2. Species dioecious.
Bulbochoete pygmoea. Wittr. Disp. CEdog. p. 141.

Oogonia ellipsoid, patent, seated beneath terminal seta?, or
vegetative cells, in longitudinal section rather quadrangular ;
androsporangia scattered, dwarf males seated about the oogonia.
(Filament at first short, and curved.)

SIZE. Cells '012-'015 mm. x a third part shorter or equal;
oogonia '023-f025 x •034->04 mm.; stem of dwarf males
•011--012 x -015--018 mm.; sperm cell -007--0075 X
•007--0075 mm.

Wittr. Mon. GEdog. p. 52. Quart. Journ. Micr. Sci. 1870,
p. 89.

Bulbochcete pygmcea, /3. minor, Prings. Beitr. p. 74, t. 6, f.
10.

Ireland, Britain.

Plate LXVIII. fig.5> Plant of Bulbochcete pygmoea, with oogonium
and (a) section of oospore x 400.

Bulbochoete insignis. Prings. Beitr. 72, i. 6, f. 7.

Oogonia ellipsoid, patent or erect, seated beneath andro-
sporangia or terminal setee ; epispore delicately transversely
striate ; androsporangia epigynous, or rarely scattered ; dwarf
males seated about or upon the oogonia.

(EDOGON1ACE.E. 177

SIZE. Cells '02-'025 mm. 2J-41 times as long ; oogonia
•046--05 x -07--1 mm. ; androspore cell -016--02 x '02--025
mm. ; stem of dwarf males -017-'0l9 X '029--031 mm. ; sperm,
cell -01--011 x -0075--008 mm.

Wittr. Mon. (Edog. p. 55. Kirch. Alg. Schles. p. 62.

Kabh. Alg. Eur. iii. 360.

Bulbochcete Pringsheimiana Arch. Proc. Dubl. Micro. Club p.
38, t. 4.

Ireland.

Plate IjXVII. fig, 4. Bulbockcete insignis, with oogonium and dwarf
male x 400.

Bulbochcete rectangularis. Wittr. Disp. (Edog. p. 142.

Oogonia ellipsoid, patent, or rarely erect, seated beneath
terminal seta3, or androsporangia, or rarely beneath vegetative
cells; androsporangia scattered or epigynous ; vegetative cells
somewhat rectangular in longitudinal section (horizontal divi-
sion of vegetative cells often occurs). Branches of the plant
few and very long ; dwarf males seated about or upon the
oogonia.

SIZE. Cells -019--023 mm., 1J-2 times as long; oogonia,
•03--039 x -048--055 mm. ; androspore cell -015--016 x -016--027
mm.; stem of dwarf males -015--018 X '022--027 mm. ; sperm,
cell -OOS--0095 x -0055--0065 mm.

Wittr. Mon. (Edog. p. 56, t. 1, f. 22-249

Ireland.

Plate LXVI1I. fig. 3. Bulboclicete rectangularis, with oogonia and
dwarf male x 400.

Species of which the organs of fructification are imperfectly

known.

Bulbochcete gracilis. Prings. Beitr. 74, t. 6, /. 9.

Monoecious (?). Oogonia oblong-ellipsoid, patent or rarely
erect, with vegetative cells above ; supporting cells without
dissepiment (?).

SIZE. Cells •013-'014mm., l^ to 1J times as long ; oogonia
•021--024 x '049--054 mm.

Wittr. Mon. (Edog. p. 57. Rabh. Alg. Eur. iii., 359. Quart.
Journ. Micr. Sci. 1870, p. 89.

Ireland.
Plate LXVI. fig. 9. BuWochoete gracilis, with oogonium x 400.

178 NEMATOPHYCEjE.

FAMILY VI. ULOTRIOHE^3.

Algae growing either in fresh water (Ulothrix), or marine or
sub-marine (Hormisrict) t or terrestrial (Hormidium, Schizo-
gonium), either of a bright green or yellowish green colour.
Threads very shortly articulate, simple, very rarely dividing into
single branches, free, now and then laterally connate in bands
(Schizogonium}.

Primitive cells always many times longer than their diameter,
after repeated division equal, or shorter (rarely a little longer),
all fertile. Cell-membrane either thin (Ulothrix, Hormidium)
or thick, sometimes very thick, and distinctly lamellose (Hor-
miscia). Cell-contents at first effused, parietal, including a
starch granule, after simple or repeated division transmuted
into gonidia.

Gonidia of two kinds, Macrogonidia sphaerical, ovoid, or
ovate-oblong, rounded at one pole, and acute at the other, fur-
nished with 2 or 4 vibratile cilia, often germinating in the
mother-cell without sexual fertilization. Microgonidia much
smaller, of similar form, furnished with two cilia at one ex-
tremity. Both kinds of zoogonidia produced within the cells of
the threads, emitted either by a poriforin opening in the mother-
cell, or by the splitting or breaking up of the mother-cell.

For detailed information on this family consult Braun's " Rejuvenes-
cence" (Ray Society), pp. 148, 161, 184, 208, 223 ; Dr. A. Dodel, " die
Kraushaar-Alge," Ulothrix zonata, in Pringsheim's " Jahrbucher," t. x. ;
Cienkowsky " Zur Morphologie der Ulotricheen " (1876) ; Thuret, in
" Ann. des Sciences Naturelles," xiv. (1850), p. 222 ; and Dr. Braxton
Hicks, in " Quarterly Journal of Microscopical Science," 1861, p. 157.

GENUS 66. HORXKZSCZA. Ares. (1866.)

Articulate thread fixed by the basal cell, which is attenuated
downwards ; simple, or now and then emitting branchlets.
Cells abbreviated, enclosed by a thick cell-membrane, which is
often manifestly lamellose. Cell-contents green, parietal,
including an amylaceous granule.

Propagation by rnacrogonidia and microgonidia. — Eabh.
Alg. Eur. in. 361.

ULOT1UCHE.E. 179

The filaments are sometimes cylindrical, sometimes tornlose like a
rosary, in consequence of the barrel-like inflation of the separate cells;
sometimes stretched out, sometimes frilled and interlacing each other,
with a relatively thicker stratified membrane. Vegetative or asexual re-
production is effected by macrozoospores, which originate 1-4 in a cell,
and after becoming covered with a transparent bladder make their exit
through an opening formed in the lateral wall of the mother-cell. The
macrozoospores are of a thick, short, pear-shape, furnished with four
cilia, a coloured spot, and a contractile vacuole. After a time they
come to rest, and fixing themselves by the mouth end, they lose their
cilia and envelope themselves in a membrane. The fixed end developes
into a root-like, colourless organ of attachment; the free end growing
into a club-shaped plantlet, through the cell, dividing into two by a cross
partition, and each of these again in two, and so further. Sexual repro-
duction arises through repeated bipartitiou in each cell, from 8-32 and
more, smaller microzoospores being produced. They have only two
cilia, and after a swarming for a time they conjugate laterally in pairs,
forming a zygospore, which attaches itself by the end corresponding to
the mouth of the microzoospore. It grows very slowly, and finally
breaks up by the simultaneous division of its plasma into 2-14 swarm-
spores, which constitute the beginning of a new sexual generation. If
any of the microzoospores remain behind in the mother cells, they are
able, without copulation, to germinate and grow into independent plants
which may be seen singly or in groups projecting from the mother-
cells.

Hormiscia moniliformis. (Kutz.} Rabh. Alg. Eur. in., 361.

Pale green, more or less crispate, often mixed with other
Alga? ; cells equal or a little shorter than their diameter ; cell-
membrane thick, colourless, somewhat lamellose, more or less
constricted at the septa.

SIZE. Cells •011-<014 mm. diam.

Ulothrix moniliformis, Kutz. Tab. Phy. ii., t. 88. Kirch. Alg.
Schl. p. 76.

In swamps, amongst Sphagnum, &c.

Plate LXX. jig. 1. Portions of threads of Hormiscia moniliformis
X 400 diam.

Hormiscia zonata. {Web. Sf M.) Aresch. Obs. p. 12.

More or less bright green, mucous, two or three feet long,
often less, either floating or interwoven, sterile cells equal, or
half their diameter ; fructiferous cells usually a little longer
than broad ; cell-nienibrane thick, slightly constricted at the
septa.

SIZE. Cells •012--04nim. ; macrozoospores -012--018 x '01
•012 mm. ; microzoospores 'OOS-'Ol x '004--007 mm.

Rabh. Alg. Eur. iii., 362.

Ulothrix zonata, Kutz. Tab. Phy. ii., t. 90, f. 2. Kirch. Alg.
Schl. p. 76. Dodel in Prings. Jahrb. t. x., pi. i.-vm.

Lyngbya zonata, Hass. Alg. 220, t. 59, f. 1-6.

2 c

180 NEMATOPHYCE^E.

Conferva zonata, Web. & Molir. in Ag. Syst. p. 90 ; Harv.
Man. 126. Eng. Fl. v., p. 351. Alack. Hib. 224. Dillw.
Conf. Syn. p. 41. Johnst. Fl. Berw. ii., 254. Gray AIT. i.,
311,

Conferva lubrica, Dillw. Conf. t. 47.

Conferva lucens, Eng. Bot. i., t. 1655 ; ii., t. 2475.

In ditches, ponds, swamps, &c.

Plate LXIX. fq. a. } „,

7 > 1 breads in ordinary condition.
»j "• J

,, c. Portion of a thread with one macrozoospore
in each cell showing the red spot.

,, d. Macrozoospores free with four cilia.

., e. Macrozoospores in the resting state.

M f. Macrozoospores germinating.

», g. Plantlet of six cells.

„ h. Threads with ripe microzoospores.

,, h2. With macro and microzoospores.

„ i. Microzoospores free with two cilia.

,, k. Microzoospores in conjugation.

-, /. Eesting zygospores, the result of the conju-
gation of pairs of zoospores.

j, m. Portion of threads with growing plantlets
arising from nncopulated microzoospores
left behind in the mother-cells.

„ n. Three healthy zygospores, 8 months and 9
days old.

,, o. Zygospore contents differentiating.

11 p. ,, in a later stage.

„ q. „ very large in two positions, show-

altogether 10 zoospores.

,, r. , , with zoospores elongated.

Hormiscia aequalis. (Kutz.) Rabli. Alg. Eur. in., 363.

Yellowish-green, cells equal, or a little longer than their
diameter ; cell-membrane, rather thick.

var. catenaefoarmis. Kutz.

Kather thicker than in the typical form ; cells a little longer
than their diameter ; cell membrane thick, striate, manifestly
constricted at the septa.

SIZE. Cells -012--018 mm. diam.

Ulotlirix cequahs, Kutz. Tab. Phy. ii., t. 89, f. 1. Kirch.
Alg. Schl. 76.

Ulotlirix catena for mis, Kutz. Tab. Phy. ii., t. 89, f. 2.

In ditches and streams (mostly rapid) attached to aquatic
plants.

Plate LXX. fig. 2. Portions of threads of Hormiscia catcnceformis
X 400 diam.

ULOTRICHE^E. 181

•

Hormiscia speciosa. (Ccmn.) Rabli. Alg. Eur. in., 363.

Dark green, 1-2 inches long, threads often crispate, cells 2-4
times shorter than their diameter, fructiferous cells subglobose.

SIZE. Cells -043-'048 mm. diani.

Ulothrix speciosa, Kutz. Tab. Phy. ii., t. 93.

Lyngbya speciosa, Carm. Alg. App. ined. Harv. Phyc.
Britt. t. 186 B. Brit. Fl. ii., 371. Wyatt Alg. Damn. No.
196.

In brackish and fresh water.

Scarcely any good features whereby this can be distinguished from H.
bicolor.

Plate LXX. fig. 3. Portions of threads of Hormiscia speciosa X 400
diam.

Hoxmiscia bicolor. (Eng. Sot. i., t. 2288.)

Bright green. Tufts very long, one foot or more ; articula-
tions two to three times shorter than their diameter, pectinate ;
cell membrane thick, distinctly lamellose.

SIZE. Cells *05 mm. diam.

Ulothrix crispa, Kutz. Tab. Phyc. ii., t. 92, f. 4. Kutz. Spec.
348.

Conferva bicolor, Eng. Bot. i., t. 2288.

Tyndaridea bicolor, Eng. Bot. ii., t. 2508. Eng. Fl. v., 361.

Ulothrix bicolor, Ralfs, Alg. Exs. No. 13.

(?) Sphceroplea crispa, Berk. Glean, t. 3, f. 1. Harv. Man.
144.

Lyngbya crispa, Jenner Fl. Tonb. Wells, 188.

In fresh water.

Whether this be really the Sphceroplea crispa of " Berkeley's Glean-
ings " seems open to reasonable doubt.

Plate LXX. Jig. 7. Portion of thread of Hormiscia bicolor with
microzoospores in lower cells X 400 diam.

GEN. 67. ULOTHRIX. Kutz. (1845.)

Threads articulate, simple ; articulations short, sometimes
shorter than their diameter, rarely a little longer ; cell mem-
brane thin, often very thin, very rarely lamellose. Cell contents
effused, green, parietal, inclosing an amylaceous granule.

The slight differences between this genus and Hormiscia sceni
scarcely sufficient to maintain them as distinct genera.

182 NEMATOPHYCK^E.

Ulothrix variabilis. Kutz. Tab. Phyc. u.,t. 85, /. 3.

Pale green ; cells equal or a little longer than their diameter,
rarely twice as long ; cell-contents at first always contracted in
a quadrate manner.

SIZE. Cells -005--007 mm.

Rabh. Alg. Eur. iii.

Ulotlirix subtilis, var. c. variabilis, Kirch. Alg. Sch. 77.

Tn ditches and slow streams.

The view entertained by Kirchner that this and V. tenerrima are
only varieties of Ulothrix subtilis is probably correct.

Plate LXX. fig. 4. Portions of threads of Ulothrix variabilis X 400
diam.

Ulothrix tenerrima. Kutz. Tab. Phy. n., *. 87, /. 1.

Pale green, or yellowish-green, lubricous ; cells mostly equal
in length and diameter, now and then a little shorter.
SIZE. Cells -007--01 mm.
Rabh. Alg. Eur. iii., 3G6.
Uloihrix subtilis ) var. e. tenerrima, Kirch. Alg. Schl. p. 77.

In ditches, turbaries, &c.

Plate LXX.fg. 5. Portions of threads of Ulothnx tenerrima X 400
diam.

Ulothrix tennis. Kutz. Tab. Pliyc. n., t. 89, /. 1, bis.

Dark green, attached, from half to two or three inches long,
mucous, cells equal or 2-4 times shorter than their diameter,
cell membrane thin, homogeneous.

SIZE. Cells •017--026mm.

Rabh. Alg. Eur. iii., 366. Kirch. Alg. Schl. p. 78.

In ditches and streamlets.

Plate LXX. Jiff. 6. Portions of threads of Ulotlirix tennis X 400
diam.

Ulothrix (Horxnidium) radicans. Kutz. Tab. Phyc. IT., t. 95, f. 3.

Yellowish green, rather rigid, densely interwoven in a soft
velvety green stratum, cells either nearly equal or 2-3 times
shorter than their diameter.

SIZE. Cells -0075--0095 mm.

Rabh. Alg. Eur. iii., 367. Kirch. Alg. Schl. p. 77.

Hormulium murale, Kutz. Phy. Germ. p. 193.

Lyngbya muralis, Ag. Syst. p. 74. Eng. Fl. v, 370. Hass,
Alg. 221, t. 59, f. 7. Eng. Bot, ii., t. 2522. Jenn. Tunb.

ULOTRICHE^E. 183

Wells, 188. Harv. Man. 160. Johnst. Fl. Berw. ii., 259.
Mack. Hib. 238.

Conferva imiralis, Dillw. Conf. t. 7. Eng. Bot. i., t. 1554.

Humida muralis, Gray Arr. i., 282.

Oscillatoria muralis, Grev. Fl. Ed. 304. Fl. Dev. ii., 57.
Hook. Fl. Scot, ii., 79.

On the naked ground, rocks, walls, &c.

Kutzing -Las in some of his works applied to the terrestrial species of
Ulothrix the generic name of Hormidium, which is only of sectional
value.

Plate LXXI. fig, 1. Portions of threads of Ulothrix radicans
X 400.

Ulothrix (Hormidium) parietina. (Vaitch.) Kutz, Tab. Phyc. n.,

t.Q7,f. 1.

Bright yellowish green, flexuous and interwoven, cells half
as long as broad, cell membrane thin, hyaline, homogeneous.
SIZE. Cells -009--016 mm.

Babh. Alg. Eur. iii., 367. Kirch. Alg. Schl. p. 78.
Hormidium parietinum, Kutz. Phyc. Germ. p. 193.

On walls, trunks, &c.

Plate LXXI, fig, 2. Portions of threads of Ulothrix parietina
X 400 diani.

GEN. 68. SCHIZOGONXUM. Kutz. (1843.)

Threads as in Ulothrix, or in many places laterally connate
(duplicate or triplicate), or by cellular division in two directions
forming narrow flat bands, which are more or less crispate.

In 18G1 Dr. Braxton Hicks indicated his belief that Schizogonium was
only a condition of Ulothrix in which the threads had become connate,
of which PrasioZa was only a frondose form. He says, "the whole of
these changes are so palpable, can be observed so constantly, and are,
at the same time, so simple in their relations to one another, that one
can scarcely imagine how they can have been separated, not only into
distinct species, but into different families of Algas. Thus the 'linear
stage is called Lyngbya (Ulothrix) ; the early stage of collateral seg-
mentation, the Schizogonium; the adult stage, the Prasiola ; while the
goniclial. growth has been classed under Palm ell acece." And again,
" the only real difference between the first two is, that whereas Lyngbya
(Ulothrix) is a tube containing distinct cells within, which, when old
undergo collateral subdivision, to form a band of two, four, or eight
rows of cells, Schizogonium is a band of two or eight rows of cells,
which, when young was but a single row, contained in a tube, which
is only two different ways of stating the same facts. The comparison
of the last two is of the same kind. For as Prasiola, when old, is com-
posed of many rows of cells, but which arose from a single row, there
must have been a time in its life when it had two, four, or eight
rows, and thus have been a Schizogonium, for there is no other

1 84 NEMATOPHYCE^E.

structural difference between the two." The whole of the communica-
tion from whence the above is quoted is worthy of attentive perusal,
at least in so far as the relations between Ulotlirix and Sckizogonitim
are concerned. It is entitled " On the Diamorphosis of Lyngbi/a^ &c.,"
in the " Quart. Journ. of Microscopical Science" for 1861, pp. 157-166.

Schizogonium murale. Kuiz. Tab. Phyc. n., t. 98, /. 1.

Dark green, forming a broadly expanded soft velvety
stratum, threads sometimes free, here and there two or three
united, cells 2-4 times shorter than their diameter, pectinate,
often crowded, sometimes interrupted, cell membrane rather
thick, colourless, slightly undulated and constricted.

SIZE. Cells -015--018mm.

Kabh. Alg. Eur. iii., 368. Kirch. Alg. Schl. 78.

On moist walls and naked ground.

Plate LJ.XI. fig. 3. Portions of threads of Schizogonium murale
X 400 diam.

FAMILY VII. CHEOOLEPIDB^.

Aerial alga3, coloured golden yellow, orange or red -brown,
when dry often becoming greenish grey ; more or less fragrant
with the odour of violets. Threads articulate, variously
branched, cell membrane thick, or somewhat thick, firm, almost
cartilaginous, collected in minute tufts, or densely interwoven
in a thin or thick tomentose stratum. Cell contents oily or
granulose, either red, orange, or yellow brown, growing paler
after death.

Propagation by zoogonidia, produced in proper cells
(sporangia) which are terminal, or by prolification formed
laterally. Zoogonidia oblong-oval, furnished at one extremity
with two vibratile cilia.— Rabh. Alg. Eur. in., 371.

GEN. 69. CHROOLEPUS. Ag. (1824.)
Characters the same as given above for the family.

There appears to us no occasion or justification for the substitution
of Trtntepohlia for the above generic name as some authors have
done.

The following is an abstract of the process of reproduction, as ob-
served by Dr. Caspary. (Flora, ^f. 28, 1£58). 'The apical cell of
the threads has often' a globular or pulvinate appendage, of a highly
refractive nature, furnished with transverse wrinkles, and frequently
also with a protuberance at the top. The whole cavity of the cells is
filled with granular matter, mostly of a brownish red colour, but it
frequently happens that the inner granules only are brownish red,

CHROOLEPIDE.E. 185

whilst the outer ones are greeii. The reddish brown, granules seem
to be oil drops A great number of the threads terminate with a globose
much thickened cell, which subsequently becomes the mother cell of
the zoospores This mother cell is rarely found in the middle of the
threads. Occasionally, but still more rarely, the cell immediately under
the mother cell elongates itself sideways and upwards into a thread.
The mother cell of the zoospores, when it forms the terminal cell of
the thread, bears a conical mass of gelatine, often of considerable size,
which, however, is seldom, on the crown of the cell, but usually at its
side. In those mother cells in which the zoospores are about to escape
a division of the contents into small oval cells is clearly perceptible,
and at the side, or near the top, the wall is extended into a short
papilla. The contents emerge in the form of a well defined vesicle,
with the zoospores penetrating through the ruptured papilla, some-
times, however, no vesicle is formed. A few moments after emerging
•the vesicle bursts, doubtless by absorption of water, and the zoospores
swim about in every direction. The remnants of the vesicle are of a
gelatinous nature. The escape of the zoospores was observed from nine
in the morning till four in the afternoon, and seems to depend not upon
the influence of light, but solely upon the effect of moistening with
water. The zoospores are very small, 'OOSo-'OOSS mm. They are
filled with reddish brown granular matter, the apex alone being free
and hyaline ; there are two cilia, about three or four times as long as
the spore. The apex with the cilia is directed forwards. They rotate
perpetually whilst swimming; their motion being so rapid as to prevent
a clear view of them, except when stopped by some obstacle, or when
their motion is becoming retarded. The cell is surrounded by a clear
highly refractive border looking like gelatine, but which may be only
an optical appearance. After continuing in motion for about an hour
the zoospores become sluggish, sink, become globular, elongate them-
selves, and shortly a division of the cell takes place by a transverse
septum. Some reddish brown granules usually remain behind in the
empty mother cell, and in the remnant of the vesicle. Oftentimes
some zoospores cannot emerge from the mother cell, and then they
sometimes germinate in it. These observations were made on a variety
of Chroolepus aureus. Quart. Journ. Micro. Science, vin. (1860), p.
159.

Chxoolepus aureus. (Linn). Kutz. Tab. iv., t. 93.

Golden red or orange. Threads either collected in small
tufts, or spreading in a soft silky stratum, sometimes intricately
and densely expanded and very much branched. Cells as long,
or two to three times as long as their diameter.

SIZE. Cells 'Ol-'Ol^ mm. diam. Zoosporangium '02 x
•03 mm.

Eng. Fl. v., p. 380. Eng. Bot. ii., t. 2528. Harv. Man.
189. Mack. Hib. 246. Rab. Alg. Eur. iii., 371.

Conferva aurea, Dilhv. Conf. t. 35.

Byssusaurea, Eng. Bot. i., t. 212. Lightf. Fl. Scot. p. 1002.
Hull Br. Fl. 307. Relhan Cant. 446. Huds. Fl. Aug. 606.
Sibth. Ox. 338. Purton Midi. Fl. ii., 606. Ray. Syn. 56, No.
6. Abbot Bedf. 276. With. AIT. iv., 144.

Ceramium aurewn, Hook. Fl. Scot, ii., 86.

Amphicomum aureum, Johnst. Fl. Berw. ii., 243.

186 NEMATOPHYCE^E.

Trentepohlia anrea, Ag. Syst. p. 36.

Ectocarpus aureus, Lyngb. Hydro. Dan. t. 4-4. Grev. Fl.
Ed. 315.

On walls, rocks, chips, bark, &c.

Plate LXXII. Jig. 1. Portions of filaments X 400 a, zoospor-
angium ; b, zoospore; c, same at rest ; d, germinating zoospore.

Chiroolepus odoratus. (Lyngb.} Ag. Syst. 35.

Stratum thin, rather toinentose, rufous -tawny (when dry
cinereous, becoming greenish). Threads and branches abbre-
viated, erect, parallel, flexuously curved, torulose ; cells equal
or twice as long as their diameter.

SIZE. Cells '02-'025 mm. diam.

Eng. Fl. v., 381. Harv. Man. 190. Rabh. Alg. Eur. iii.,
372.

Conferva odorata, Lyngb. Hydr. Dan. t. 57. Johnst. Fl.
Berw. ii., 245.

On the bark of various trees, especially of Birch and
Poplar.

Plate LXX1I. fig. 2. Portion of thread of Chroolepus odoratus x 400.

Chroolepus lolithus. (Linn.) Ag. Syst. p. 34.

Stratum thin, or a line thick, reddish-orange, glaucous or
dirty greenish when dry, threads and branches elongated, rather
dichotomous, variously curved, ascending ; cells one and a half
or three times as long as their diameter, in the upper portion
of the branches reaching to double that proportion.

SIZE. Cells '025-'04 mm. diam. Zoosporangium *05 mm.
diam.

Eng. Fl. v., 380. Eng. Bot. ii., p. 189. Harv. Man. 189.
Mack. Hib. 246. Rabh. Alg. Eur. iii., 373.

Byssus lolithus, Linn. Spec. 1638. Hull. Br. Fl. 308.

Olivia riolacea, Gray. AIT. i., 350.

Trentepohlia lolithus, Wallr. Comp. iv. 151.

On rocks, in moist places.

Plate LXXII. fig. 4. Portion of thread of Chroolepus lolithus X 400 ;
a, zoosporangium x 400.

Chroolepus ilicicolus. Eng. Bot. ir., t. 2529.

Filaments erect, alternately branched, forming tufts of a
permanent tawny-yellow. Cells nearly as long as broad.
SIZE. Cells about -03 mm. diam.
Conferva ilicicola, Eng. Bot. i., t. 1639.

CHMOOLEl'IDEyE. 187

Chroolepus aureus, Eng. Fl. v., 380, in part.
On Holly bark.

Included in Harvey's Manual (p. 189) under Chroolepus
aureus. Figured from the original specimen.

Plate LXX1I. fig. 5. Portion of thread of Cliroolepus ilicicolus
X400.

Chroolepus lichenicolus. Ay. Syst. 34.

Tufts red-orange ; threads erect, tufted, alternately branched,
rigid ; cells slightly tumid, as long as broad.

SIZE. Cells '012 mm. cliam. Zoosporangium about '015
mm. cliarn.

Eng. Fl.v., 381. Eng. Bot. ii. t., 2530. Harv. Man. 190.
Mack. Hib. 247.

Conferva lichenicola, Eng. Bot. i., t. 1609. Dillw. Conf. p.
56.

Chroolepus abietmum, Rabh. Alg. Enr. iii., 372, in part.

On Lichens and old trees.

Figured from the original specimens.

Plate LXXIJ. fig. 3. Portion of thread of Chroolepus alietinum,
var. lichenicolus X 400.

Species Excluded.

Chroolepus Arnottii. Harv. Man. p. 191.
This is a fungus, Antennaria Amottii, Berk in Herb.

Chroolepus ebenea. Harv. Man. p. 189.

Conferva ebenea, Dillw. Conf. t. 101.
Byssus nicjra, Eng. Bot. i., t. 702.

Probably a species of Helminthosporium.

Chroolepus melaenus. Carm. in Harv. Man. p. 189.

Conferva melaena, Lyngb. Hydrot. 57.
Apparently a Torula.

Chroolepus mesomelas. Carm. in Harv. Man. p. 189.
Torula mesomela, Carm. Alg. App.

We have seen no specimen, but it would appear from descrip-
tion to be Helminthosporium.

2 D

188 NEMATOJPHYCE^.

FAMILY VIII. CH^ETOPHORACBJB.

Aquatic or swamp-living algaa, rarely terrestrial, monoecious
or dioecious. Articulate filaments various, often dichotomously
branched, not rarely fasciculately branched, accumulated in
tufts or pulvinules, nestling in a somewhat fluid or firm gela-
tinous mucus, or constituting, for the most part, a filamentose,
rarely a somewhat foliaceous thallus (formed from a single
stratum).

Propagation by oospores after sexual fecundation, or by zoo-
gonidia ; the latter produced singly, or by the division of the
cytioplasm, or contents of the sporangium, into eight or sixteen.

GENUS 70. MIC ROTH AMNION. Nag. (1849.)

Articulate filament dichotomously or trichotomously branched,
now and then very much branched, straight, with the terminal
cell obtuse, or nearly so, afterwards swollen, forming a sporan-
gium. Cell contents effused, containing scattered amylaceous
granules. Propagation by zoogonidia. Plants microscopical,
more or less with a gelatinous investment.

Microthamnion vexator. Cke. in Grevillea xi., p. 75.

Filaments erect, very slender, dichotomously branched, more
or less growing in tufts. Cells cylindrical, longer than broad,
not at all constricted at the joints, dissepiments scarcely visible.
Cell membrane thin, pellucid.

SIZE. Cells about -003 mm. diam.

Attached to aquatic plants in clear springs, &c.

A very delicate plant, first found by Mr. Turner in Yorkshire,*aud
since detected in several localities in England. Very much more slender
than M. strictissimum*

Plate LXXIII. fy 1. Filaments of Microthamnion vexator X 400.
#, tufts of plants natural size.

GENUS 71. STIGEOCLONIUM. Kutz. (1843.)

Articulate threads simply branched, branches and branchlets
scattered, rarely approximate in a fasciculate manner, acute at
the apex, sometimes attenuated into a colourless bristle, at times
extended very long, at other times furnished with shortly
subulate branches. Cell membrane very thin and hyaline, homo-
geneous. Cell contents with the chlorophyll arranged in
transverse bands.

CHJSTOPHORACEJ2. 180

Propagation by oospores or zoogonidia, the latter formed by
division (4-16) of the cell contents, each zoospore furnished with
a red parietal spot and four vibratile cilia.

Stigeoclonium thermale. Braun in Kutz. Spec. p. 352.

Bright green, very much branched in a fasciculate manner,
somewhat creeping at the base, filaments and branches attenu-
ated upwards to the cuspidate apex, branchlets for the most
part alternate, rather remote, nearly erect or somewhat diver-
gent, setiform, joints variable in length, at the base of the
filaments equal or twice as long as the diameter, becoming
turgid, in the upper part of the branchlets 3-5 times as long a*
the diameter ; chlorophyllose bands broad, sometimes effused.

SIZE. Cells -012 mm.

Kabh. Alg. Eur. iii., 376. Kutz. Tab. Phyc. iii., t. 2, f. 4.
Draparnaldia elongata, Hass. Alg. 123, t. 10, f. 3. Ann.
Nat. Hist. Aug. 1842, xi., p. 4.

In thermal springs, &c.

Hassall found this species on one occasion growing in a horse-trough.
It is sometimes mixed with other algae in ditches.

Plate LXXIII. fig. 2. Filament of Stigeoclonium thermale with
zoogonidia X 400 diam.

Stigeoclonium tenue. Ag, Syst. 57.

Bright green, lubricous ; filaments a little branched, branches
nearly simple, cells equal or 2-3 times as long as their diameter,
more or less distinctly constricted ; chlorophyllose bands
narrow ; branchlets scattered, shortened, nearly erect, subulate ;
cells at the base longer than broad, abbreviated towards the
apex.

SIZE. Cells -01 mm. diam.

Kutz. Tab. Phyc. iii., t. 3, f. 1. Rabh. Alg. Eur. iii., 377.
Kirch. Alg. Schles. p. 68.

Draparnaldia tennis, Eng. PI. v., 388. Eng. Bot. ii., p. 199.
Harv. Man. 122. Mack. Hib. 222. Hass. Alg. 123, t. 11,
f. 2.

Conferva lubrica, Dillw. Conf. t. 57. Grev. Fl. Ed. 318.
Hook. Fl. Scot, ii., 82. Gray Arr. i,, 303.

Conferva exigna, Dillw. Conf. t. 2 (young),

In streams and ditches.

" At first the filaments are enclosed, in the manner of a Cktetophora,
in a common, somewhat definite gelatine ; afterwards, on its bursting,
they issue from it like a Conferva, but aro at all times very gelatinous."
—Harvey.

Plate LXXIII. fig. 3. Filament of Stigeoclonium tenue X 400 diam.

190 NEMATOPHYCE^E.

Stigeocloniunx protensum. (Dillw.) Kutz. Tab. Phyc.ui.,t. 8, /. 2.

Pale green, csespitose, slender ; filaments and branches long-
drawn out ; cells almost cylindrical, equal or twice as long as
their diameter ; terminal cell extended into a colourless bristle ;
branches usually scattered, rarely in pairs, with the extremities
cuspidate, piliferous.

SIZE. Cells '015 mm. diam.

Kabh. Alg. Eur. iii., 378.

Draparnaldia condensata, Hass. Alg. 122, t. 11, f. 1. Ann.
Nat. Hist, xi., 429.

Conferva protensa, Dillw. Conf. t. 67. Gray. Arr. i., 303.

In slow streams.

Plate LXX1V. jig. 1. Filament of Stigeoclonium protensum. a,
zoospores X 400 diam. ; b, branchlet of form called S. irreyulare X
400 diam.

Stigeoclonium nanum. (Dillw.) Kutz. Spec. p. 352.

Filaments alternately branched ; branches abbreviated, a
little attenuated upwards, obtuse, not piliferous ; cells equal or
a little shorter than their diameter, in the upper part equal.

SIZE. Cells '008 mm. diam.

Kabh. Alg. Eur. iii., 380.

Draparnaldia nana, Hass. Alg. 124, t. 10, f. 3.
Draparnaldia sparse^ Hass. Ann. Nat. Hist, xi., 428.
Conferva nana, Dillw. Conf. t. 30.

In streams (the Wye).

The following are Dillwyn's remarks on this species : — " The minute-
ness of the filaments, which in length seldom much exceeded a line,
prevented me from ascertaining their nature so fully as I could have
wished. Their colour is pale brown, tinged with green, sub-diaphanous
under the microscope. They appear to consist of a single stem, beset
at uncertain distances with alternate branches, which are again clothed
with short, simple, solitary ramuli, placed at small distances from each
other, most commonly alternate, although sometimes two or more
together are disposed on the same side. All of them are finely acumi-
nated; the dissepiments are very apparent, and divide the filament into
joints, all of equal size, of which the length is about double the thick-
ness. To the naked eye this plant appears, when taken from the water,
like a mere mass of decaying vegetable matter. Its extreme minuteness
might fairly induce a suspicion whether it is in reality anything more
than the seedling of some known Conferva. It adheres to either glass

*o

or paper."

Plate LXXIV. j)g. 2. Filament of Stigeoclonium nanum X 400
diam., figured from Dillwyn's original specimen.

(JIl.ETOl'HORACEJE. 191

Stigeoclonium fastigiatum. (Rolfs.} Kut~. Tab. Pliyc. in.,

t. 8, f. 1.

Pale green, small, thread very much branched, fastigiate,
radiately disposed, mucous, upper branches alternate, fastigiate,
moniliform, somewhat pinnate, a little spreading, extended at
the apex in a long bristle ; cells of the filament three times as
long as broad, the branches equal or twice as long, swollen,
constricted at the joints.

SIZE. Cells '012 mm. diam.

Eabh. Alg. Eur. iii., 380.

Chcetophora fastigiata, Ralfs. Alg. Exs., No. 9.

Attached to aquatic plants.

Plate LXXir. jig. 3. Filament of Stiyeoclonium fastigiatum X
400 diam.

GENUS 72. DRAPARNALDIA. Ag. (1824.)

Articulate thread simply branched, formed of large cells, for
the most part hyaline, with a broad chlorophyllose band, always
sterile; more or less densely furnished with penicellate fascicu-
late branchlets, alternate or opposite, composed of smaller
fertile cells. Terminal cells of all the branches empty, hyaline
and sterile, more or less elongated into a bristle.

Propagation by resting spores or zoogonidia.

Drapaxnaldia glomerata. Ag. Syst. p. 59.

Filaments and primary branches colourless, or nearly so ;
lower cells equal, or a little shorter than their diameter, dis-
tinctly constricted at the joints ; chlorophyllose bands narrow,
pale green, primary branches spreading at right angles, some-
times opposite ; fascicles of the branches crowded, alternate or
opposite, densely branched, obtuse, oval.

SIZE. Cells of main thread '035 mm., of fascicles '008 mm.

Eng. Fl. v., 388. Jenner Tunb. Wells 176. Eng. Bot. ii.,
t. 2545. Harv. Man. 121. Grev. Fl. Ed. 321. Mack. Hib.
222. Flor. Dev. ii., 50. Hook. Fl. Scot, ii., 77. Gray. AIT.
L, 302. Hass. Alg. 120, t. 13, f. 1. Eabh. Alg. Eur. iii., 381.
Kirch. Alg. Schles. p. G7. Kutz. Tab. Phyc. iii., t. 12.

Conferva mutabilis, Dillw. Conf. t. 12. Eng. Bot. i., t.
1746.

Batraclwspermum conglomeration, Yaucli. Conf. t. 12, f. 1.

In clear pools or slow streams.

192 NEMATOPHYCE.E.

Very common, and well known. Variable in the size, number, and
disposition of the fascicles.

Plate LXXV. fig. 1 . Portion of filament of Draparnaldia glomerata
X 400 diam. Fig. 2, portion of filament of the variety distans X 400
diam.

In 1857 Dr. Braxton Hicks first described in the "Journal of the
Linnean Society" (Vol. i., p. 192) what he believed to be a new species of
Draparnaldia under the name of Draparnaldia crudata, of which we
know nothing except from his description and figures, from which we
are disposed to regard it as a variety of Draparnaldia glomerata. It
was first found in the New Forest, and Avas more fully illustrated in the
" Quarterly Journal of Microscopical Science " (Vol. ix., 1869, p. 383,
pi. xix.). " Nothing," he says, " is more remarkable than the direction
taken by the branches, which diverge strictly at right angles to the
stem. Even the lesser kind, called tufts, and their branchlets, pass off
in this way, and as four generally spring from the same joint, there is
a cruciate arrangement in every part."

The following is given as its description : — " Frond 3-4 inches long.
Light green colour, not so green as D. glomerata and D. plumosa,
possessing a flocculent appearance when in water, and highly mucous
when out of water. Every portion is surrounded by a distinct layer of
transparent mucous, extending on each side to the distance of three
diameters of the included ramulus. This is most easily seen after two
days, when extraneous matter adheres to the mucous. The main filament
is composed of cells very slightly inflated, 3-4 times longer than wide,
about g-i^th °f an in°h wide, delicately fasciated. Primary ramuli pro-
ceeding at right angles, chiefly in whorls of four, from the main
filament, with an interval of 50-60 cells. The sub-ram uli also proceed
in the same way from the primary rarnuli, giving the plant a cruciate
appearance. The cells of the ramuli as wide as long, the larger fasciated,
the smaller quite filled with green chlorophyll. The interspace of 50-60
cells of main filament being great, to the naked eye it appears
nearly bare, but by higher magnifying powers small tufts, like
those terminating the sub-ramuli, appear at about every ten
cells; some larger, and approaching somewhat the sub-ramuli,
while the others are very simple. The larger terminal and lateral
tufts have a pyramidal form, and from all their divisions pro-
ceeding at right angles it appears much like a fir tree. All
the ultimate tufts bear cilia, as in the other Draparnaldife, but of
extreme length and tenuity. From the 1-3 basal cells of the ramuli
often roots spring, coiling themselves round the main filament, and
even spreading away from it, and sometimes the free point becomes
converted into a tuft, like those on the main filament. The smaller
tufts at times possess them. When the plant is mature the ramuli
disengage themselves, and can be seen floating about with their roots,
probably ready to attach themselves to any suitable object, and so
become separate plants. Zoospores not so large as in D. glomerata,
being oval, and about '0004 X '0003 inch. A whole tuft undergoes the
process simultaneously."

" It can easily be distinguished from D. plumosa and D. glomerata
by the divisions diverging at right angles, and in whorls of chiefly
four (giving the cruciate appearance), the perceptible mucous sheath,
exceeding delicacy of the cilia, extreme tendency to give out radicles,
the nearly equal width of the main cells, as also their greater length.
The fir tree-like form of the tufts are so unlike the flexible shape of
the other species."

A comparison of the plate given with the description we are bound to
say does not completely bear out all the distinctions.

CHJETOPHORACE^E. 193

Drapaxnaldia plumosa. (Vanch.) Ag. Syst. p. 58.

Threads and primary branches hyaline, cells equal or shorter
than their diameter, rarely a little longer, a little, or but scarcely
constricted at the joints, chlorophyllose bands narrow, bright
green, lower cells of the branches equal or almost twice as long
as their diameter, upper cells cylindrical, attenuated, 2-5 times
as long as broad, sometimes not piliferous, fascicles of the branches
densely branched, elongated, with an acutely lanceolate outline,
erect, somewhat appressed.

SIZE. Cells of main thread -045 mm., of fascicles '008 mm.

Eng. Fl. v., 388. Eng. Bot. ii., t. 2544. Haw. Man. 121.
Jolmst. Fl. Berw. ii., 258. Mack. Hib. 222. Flor. Dev. ii., 50.
Hook. Fl. Scot, ii., 77. Gray AIT. i., 303. Hass. Alg.121, t.
12, f. 1. Rab. Alg. Eur. iii., 382. Kirch. Alg. Schles. p. G7.
Kutz. Tab. Phyc. iii., t. 14.

Conferva lubrica, Eng. Bot. i., t. 2087.

In slow streams or pools.

Much less common than the preceding species.

Plate LXXVI. Jic/.l. Portion of filament of Draparnoldia plumosa,
X 400. Fig. 2. Portion of filament of the variety pulohel la X 400.

GENUS 73. CHJETOFHORA. Schrank. (1789.)

Articulate filaments, with the primary branches radiately dis-
posed, composed of elongated vegetative cells, with chlorophyll
bands as in Draparnaldia and Stigeoclonium ; divided upwards
into numerous branchlets, which are shortly artoculated, the
ultimate joint attenuated, often empty, scarcely or not at all
lengthened into a thread, ultimate branchlets in more or less
crowded fascicles, involved in a firm gelatinous, coriaceous, or
hard mass, of a globose or subglobose, or plane, expanded,
variously lobed form. Propagation the same as in the preced-
ing genera.

Chaetophora pisiformis. (Roth.} Ag. Syst. p. 27.

Thallus globose, about the size of a pea, often smaller (now
and then as large as a cherry), bright green, even, shining,
sometimes aggregated, not rarely confluent.

SIZE. Cells '006-'009 mm., of branches '006 mm.

Hass. Alg. 128, t. ix., f. 5, 6. Kutz. Tab. Phy. iii., t. 18,
fig. 3. Grev. Sc. Crypt. Fl., t. 150. Rabh. Als?. Eur. iii., 383.
Kirch. Alg. Schl. p. 69. Eng. Fl. v., 389. Haw. Man. 123;
Berk. Glean, t. 1, f. 1.

194 NEMATOPHYCE.E.

Ulrapisiformis, Huds. Fl. Aug. 572. With AIT., iv. 120.
Chcetophora elegans, Lyngb. Hydro, t. 65.

On submerged plants.

Plate LXXVII. fig. 1. Plants of Clicetopliora pisiformis, natural
size, and filaments X 400.

Chaetophora tuberculosa. (Rotli.') Ag. Syst.

Thallus subglobose, the size of a cherry, bright or pale green,
surface tuberculose, elastic, fascicles of branches very dense,
lower articulations cylindrical, the upper swollen, extremities
cuspidate, sharp pointed, rarely hair-like.

SIZE. Cells •0.09->012nim., of branches -OOS-'Ol mm.

Harv. Man. p. 122. Hciss. Alg. 126, t. 9, f. 7, 8. Kntz.
Tab. Phyc. iii., t. 10, f. 1. Rabh. Alg. Eur. iii., 383. Eng.
Fl. v., 389. Jenner Tunb. Wells p. 178. Eng. Bot. ii., t.
2547. Jolmst. Fl. Berw. ii., 260. Mack. Hib. 223. Hook.
Scot, ii., 76. Kirch. Alg. Schles. p. 69.

Rivularia tuberculosa, Eng. Bot. i., 2366.

In clear water.

Plate LXXriII, fig. 1. #, plant of Ch<?toj)hora tuberculosa, natural
size, b, filaments of same X 400 diam.

Chaetophora elegans. (Roth.) Ag. Syst.

Thallus the size of a pea or a cherry, pale green, surface
even, elastic, soft, now and then becoming hard, fascicles of
branches lax, rather flaccid, extremities shortly cuspidate, often
terminating in a hair.

SIZE. Cells -007--009 mm., of branches -005--007 mm.

Kutz. Tab. Phyc. iii., t. 20, f. 1. Rabh. Alg. Eur. iii., 384.
Kirch. Alg. Schl. p. 69. Eng. Fl. v., 389. Jenner Tunb.
Wells 178. Mack. Hib. 223. Harv. Man. 122. Grev. Fl.
Ed. p. 321. Hass. Alg. 127, t. 9, f. 3, 4.

Rivularia elegans, Eng. Bot. i., t. 1797. Purton Mid. Fl.
ii., 618.

In clear water, attached to submerged plants.

Paler in colour, and more hyaline and gelatinous than C. pisiformis.
Plate LXXVII. jig. 2. a, plants of Qlitttopliora, elegans natural
size, b, zoogonidia. c, filament X 400.

Chaetophora endiveefolia. Ag. Syst. p. 28.

Thallus' linear, flattened, -|-1 inch, now and then elongated,
bright or dark green, dichotoniously laciniate (sometimes with
the habit of Riccia fiuitans'), threads and primary branches
mostly colourless, here and there with green zones, parallel ;

195

fascicles of branches lateral, more or less dense, spreading arti-
culations more or less swollen, nearly equal in length and
diameter, constricted at the joints, cell contents granulose,
effused.

SIZE. Cells 'Ol-'Olo mm., of branches 'OOS-'Oll mm.

Kutz. Tab. Phy. iii., t. 21, f. 2. Rabh. Alg. Eur. iii., 385.
Kirch. Alg. Schl. p. 70. Eng. Fl. v., 389. ' Eng. Bot. ii., t.
2546. Harv. Man. p. 122. Jolmst. Fl. Berw. ii., 261. Mack.
Hib. p. 222. Hook. Fl. Scot, ii., p. 76. Hass. Alg. 125, t. 9,
f. 1, 2.

Batrachospermum fasciculatum, Vanch. Conf. p. 116, t. 13.

Ulva incrassata, Eng. Bot. i., t. 967. Hucls. Fl. Ang. ii.,
572. With. AIT. iv., 124.

Conferva geiatinosa Dames cornu, Ray Syn. p. 60.

Tremella geiatinosa Dama cornnum,T)i\l. Muse. 51, 1. 10, f. 10.

Rivularia incrassata, Purton Mid. Fl. iii., p. 179.

Myriodactylon endivce/olium. Gray AIT. i., 302.

In ditches, &c.

Exceedingly variable in the form of the thallus, and hence divided
into 7 or 8 varieties.

•

Plate LXXFIII. -jig. 2. «, plants ra endivcefi lia,

natural size, b, portion of filament X < liani.

Chaetophora punctiformis. Kutz.

Ecliinella articulata, Eng. Bot. ii., t, i

Conferva echinata, Eng. Bot. i., t. 1378.

Assuming that Mr. W. Phillips (Grevillea
correct in the presence of globose basal spores, this
to find a place in Rivularia, and not in Chcetophora.

GENUS 74. COLEOCH-ffiTE. .5;^. (1844.)

Articulated filaments branched, either united in a pulvimile,
or little cushion, or expanded in a flat, somewhat disc-shaped
parenchymatous thallus ; cells oblong, more or less dilated in
front, sometimes bearing from the back or upper surface a
hyaline bristle, which is sheathed at its base.

Propagation by oospores resulting from sexual fertilization,
and by zoogonidia. Zoogonidia single in the fructiferous cells,
either globose or broadly oval, furnished with two vibratile cilia.

The ColeochaBteae are small discoid Algae, from 1 to 2 mm. in diam.,
bright green colour, constructed of branched rows of cells. They are
found attached to submerged plants in stagnant or slow-moving streams,
and form circular, closely-pressed discs. The chlorophyll is in parietal
plates or large grannies. Some of the cells bear colourless erect bristles
fixed at the base in narrow sheaths.

2 E

JI9G NEMATOPHYCE.E.

Reproduction takes place by means of asexual zoogonidia, and sexu-
ally produced oospores. The latter do not at once produce new plants,
but several zoospores. The zoospores, which are developed in the early
part of the year from resting- spores of the previous year, produce only
asexual plants which only form zoogonidia. After a series of asexual
generations, of variable length, a sexual generation arises, which accord-
ing to the species is monoecious or dioecious. Fertilization produces
one oospore in the oogonium, which developes into a reproductive body,
from the cells of which zoospores proceed in the next period of vegeta-
tion. Zoogonidia may originate in all the vegetative cells of the Coleo-
cha3tea3, and are always formed from the entire contents of the mother-
cell, escaping through a round hole in the cell wall.

<;Iii C. piih-htatd the terminal cell of a branch swells up, and at the
same time elongates into a narrow sac, which then opens, and exudes a
colourless mucilage. The protoplasm of the swollen part, which con-
tains chlorophyll, forms the oospore, in which a nucleus is visible. The
antheridia are formed at the same time in adjoining cells, two or three
protuberances growing out, which become separated by septa ; each of
the cells thus formed, which have somewhat the shape of a flask, is an
antheridinm ; its entire contents form an antherozoid of oval shape
with 2 cilia, which is endowed with motion like a zoogonidium; its
entrance into the oogonium has not yet been observed. The effect of a
fertilization is seen in that the contents of the carpogonium become
surrounded with a proper membrane and form the oospore."

Coleochsste soluta. Prings. JaUrb. t. I,/. 2.

Threads radiating from a common centre, furcately branched,
of equal length, closely packed side by side, prostrate, but not
connate, forming ar •n-bicular disc. Cells one and a-half to
three times as -long as broad, oogonia placed before the terminal
cells, glo^se, corticate.

SIT-. Cells -025 mrn.

tf abh. Alg. Eur. in., 389. Kirch. Alg. Scliles. p. 50.

Attached to aquatic plants.

Plate LXXriII. Jig. 3. Plant of Coleoclicete soluta X 400. «, Oogo-
nium X 250 diam.

Coleocliaete scntata. Brcb. Ann. SGI. Nat., 1844, p. 29, t. 2.

Filaments and their branches radiating from the centre, very
densely connate in one stratum, forming a kind of parencby-
matous orbicular disc ; cells quadrangular, nearly equal or twice
as long, oogonia subglobose, peripherical, corticate above, naked
below.

SIZE. Cells -02--022 mm.

Rabh. Alg. Eur. iii., 390. Hass. Alg. 217, t. 77, f. 6.
Prings. Jahrb. t. i., f. 4 ; t iii., f. 3, 4.

Phyllactidium setigemm, Kutz. Tab. Phyc. iv.

On aquatic plants.

Plate LXXIX. Coleoclicete scntata. a, plant X 200. b, portion with
oogonia. c, portion with antheridia cells, d, zoospore, active and at
rest, e, development of young plants.

CH.ETOPHORACEJL. 197

Coleochaete oxbiculaxis. Prings. Jakrl>. t. 1, /. 5.

Disc orbicular, parencliymatous, formed from one stratum of
cells, bright green, cells oblong-quadrangular when old, by
pressure becoming often polygonal, usually twice as long as
broad. Oogonia oval, peripherical, mostly naked.

SIZE. Cells -012--017 mm.

Babh. Alg. Ear. iii., 390. Kirch. Alg. Schles. p. 50.

Phyllactidium pulchellum, Kutz. Tab. Phyc. iv.

On aquatic plants.

Plate LXXX. fig. I. a, plant X 200. b, portion with oogonia, after
Pringsheim X 250.

GENUS 75. APKANOCHJETE. Braun. (1847.)

Articulate threads prostrate, somewhat creeping, sometimes
more or less united in an irregular stratum. Branches decum-
bent or ascending, cells bearing on their apex or back, often a
long bristle which has no sheath at the base. Propagation by
zoogonidia. Oogonia at present unknown.

Aphanochaete jrepens.

Filaments and branches procumbent, fn rhtly

swollen, of equal diameter in both
indistinctly articulated bristle.

SIZE. Cells -005 --01 mm.

Rabh. Alg. Eur. iii., 391. Kirch. Alg. Schles. p. 71.

On Cladophora jlavescens, and other Alga?.
Plate LXXX. fig. 3. Plant of Aphanochtfte repens X 400.

Aphanochaete hystsrix. (Thiu.) Baoli. Alg. Eur. in. 391.

Filaments and their branches radiating, procumbent, ad-
pressed ; more or less connate, in a pale green irregular discoid
thallus. Cells somewhat cylindrical, produced at the apex into
a long bristle, which is not articulated.

SIZE. Cells '01 mm. diam.

Ochlochcste hystrix, Thwaites in Harv. Phyc. Britt. t. 226.

On aquatic plants in brackish ditches.

Perhaps scarcely deserving a place here, as it is almost, if not quite,
a marine species.

Plate LXXX. fg. 2. a, plant of Aphcmochci-te hysiria\ slightly
magnified, b, portion more highly magnified, after Harvey.

198

APPENDIX

TO CHLOROPHYLLOPHYCEJB,

In the form of an Appendix, we shall here enumerate a few
species, of doubtful position, which are not known with sufficient
exactitude to be recorded in systematic order, although their
affinities appear to be with the Algas. The Saprolegniece are
not included, because they are now generally acknowledged as
Fungi. The genus Syncliitrinm also appears to be more nearly
related to Protomyces, amongst Fungi, than to Algfe.

FAMILY. CHYTKTDIE^E.

Plants for the most part aquatic, parasitic, epiphytal or endo-
phytal, occasionally epizoic, very rarely terrestrial, one or two-
celled. Cells vesiculose, single or gregarious, either innate in
the fostering plant, or penetrating its membrane ; furnished
with radicles at the base, or destitute of them ; now and then
numerous and densely aggregated, involved in a common mem-
brane, nestling in the parenchyma of terrestrial plants, and form-
ing pustules. Protoplasm mucilaginous, usually colourless,
sometimes coloured. Antheridia not yet observed. Propaga-
tion by oospores or zoogonidia.

Some authors have united the majority of the species under the one
genus Chi/tridium, whilst others have distributed them over several
genera, as Chytridium, Phlyctidium, Rhyzophidiitm. Ofyidiicm, and
Rhizidlum, but apparently without good reason.

GENUS 76. CHYTRIDIUM. Srann. (1851).

Cells globose or somewhat pear-shaped, operculate above, the
root-like base usually innate in various algas, penetrating the
membrane of their cells.

Zoogonidia very numerous, globose, with a nucleus, bearing a
single very long ciliuni, escaping through the orifice of the cell
caused by the falling away of the operculum.

CHYTRIDIE.E. 199

" The Chytridia form a genus of unicellular, parasitical Algre, or, if it
be preferred, of aquatic Fungi, related to Saprolegnia about as much as
Ascidium is to Bryojjsis. The entire plant is composed of a single balloon-
shaped cell, which penetrates into the Algas upon which it grows, by a
more or less developed root-like base. The inflated portion of the cell is
filled with colourless mucilage, from which are formed, not through suc-
cessive division, but by a simultaneous process, very numerous small
globular germ-cells, which exhibit a sharply-defined darker nucleus in the
interior, and possess a single very long cilium. From their want of
colour and the activity of their motion these gonidia resemble the most
minute monads. Their extrusion occurs either through the casting off of
a lid or through mere tearing of a nipple-shaped point. Of fifteen different
species which I have observed in the vicinity of Freiburg, Chytridium
olla is the largest, and at the same time exhibits the lid-like dehiscence
most beautifully. It grows on the anterior wrinkled end of the bulging
parent-cells of the spores of (Edogonium Landsboroughii, the root pene-
trating into the folds and attaching itself to the spore. The free inflated
portion of the cell is ovate, with the lid somewhat thrown up at the
edges, and apiculated like a short nipple in the middle. The germ-cells
are about '003 mm. diarn." — Braun, Rejwenescence, pp. 186 note.

See also Braun, " Ueber Chytridium " (Berlin, 1856) ; Cohn in " Hed-
\vigia," 1865, p. 170 ; Nowakowski " Beitrag zur Kenntniss der Cbytri-
diaceen ' (Breslau, 1876).

Chytridium acuminatum. Braun Chytr. p. 28, t. 1, /. 11.

Cells much smaller than in Chytridium olla, ovate-pyriform ;
operculum acuminate.

SIZE. Cells '016 mm. long.
Eabh. Alg. Eur. iii., p. 277.

Parasitic on species of QZdogonium.

Plate LXXXI. jig. 1. Chytridium acuminatum parasitic upon (Edo-
gonium Rothii X 400 diam.

GENUS 77. RHIZOPHYDIUM. Schenk. (1858.)

Cells globose, ovate, or broadly clavate, with 2, 3, or more
scattered orifices, more or less elongated into a neck, furnished
with, or destitute of, distinct radicles at the base.

Rhizophydium Barkerianum. (Archer.) Eabh. Alg. Eur. in. 281.

Cells much depressed, 3 or 4 lobed, the lobes broadly rounded ;
upper surface of the cell concave, bearing at the centre a ver-
tical hyaline, very slender, terete, minutely capitate process ;
cell contents mainly confined to the centre, leaving the ends of
the lobes empty ; zoospores making their exit through the
opened apices of the lobes.

Chytridium Barkerianum, Archer in Quart. Journ. Micr. Sci.
1867, p. 89.

Parasitic on Zygnema. Gallery Bog (Ireland).

We have seen no specimens, and are not aware of any figure extant, or
of any dimensions having been recorded.

2 F

200 CHYTRIDIE^.

GENUS 78. OLFIDXUM. Braun. (1856.)

Cells globose or subglobose, parasitic, epiphytal, or endo-
phytal, not operculate, nor rooting ; mouth vertical, elongated
into a cylindrical tube.

Olpidium endogenum. Braun CJiytrid. Fo. 20, t. v., f. 21.

Parasitic in the interior of plants, usually gregarious, de-
pressedly globose, extended at the apex into a tubular neck,
which is globosely dilated in the middle ; perforating the mem-
brane of its host, is extended beyond with a funnel-shaped
mouth.

SIZE. Cells about '024 mm. diam.

Olpidium intestinum (Braun), Eabli. Alg. Eur. iii., 283.

Parasitic in Closteriwn, Vaucheria, &c.

This appears to be the species figured by Henfrey as occurring within
the cells of Eremosphcera vindis in '' Quart. Journ. Micr. Sci." vii. (1859),
t. 3, figs. 11, 12. Also by Carter in Spiroqyra, in " Annals of Natural
History," 2nd Series, Vol. xvii. (1856), t. 9, 'figs. 9 and 10.

Plate LXKX1. ficj. 2. Olpidium endogenum parasitic in Closterium
lunula X 400.

Olpidium ampullae eum. (Braun.} Rabh. Alg. Eur. ill., 282.

Epiphytal, gregarious, globose, small, sessile, rarely pedicel-
late, tubular, mouth erect, cylindrical, about as long as the cell,
terminating in a conical apiculus.

SIZE. Cells "0065 mm. diam.

Chytridium ampullaceum, Braun Chytrid., p. 66, t. 5, f. 24-27.

Parasitic on various alga3.

It was probably this, or a closely-allied species, which was figured by
Henfrey as parasitic on Eremosphcera viridis in " Quart. Journ. Micr.
Sci." vii. (1859), t. 3, f. 13, 14.

Plate LXXXL fig. 3. Olpidium ampullaceum parasitic on Mougeotia
X 400 ; 3a, individual further magnified. Fig. 4, allied species x 400.

GENUS 79. SYNCHITRIU1VI. D.By. % Wor. (1863.)

Thallus multiform. Cells (sporangia of some authors) often
numerous and aggregated, closely involved in a common mem-
brane, forming sori, filled with delicately granular orange con-
tents. Zoogonidia globose, rarely oval or oblong, with a lateral
orange-red nucleus, bearing a single (rarely 2) very long cilium.

Inhabiting the substance of plants, with the habit of Ure-
dines, but without mycelium.

CHYTRIDIE.E. 201

Synchitrium Taraxaci. D. By. $ Wor. Bericht. der Naturf. Ges.

Freiburg in., t. 2, /. 1-7.

Orange warts, about *5 mm. diam., prominent on both sur-
faces of the leaf, scattered or crowded. During summer each
wart contains a mass of crowded cells, polygonal or rounded,
variable in form and size, filled with granular orange proto-
plasm, which break up into globose, ciliated zoogonidia.

SIZE. Zoogonidia '003 mm. ; cellules '02-'06 mm. diam.

Parasitic beneath the cuticle of living leaves of dandelion
(Taraxacum officinale).

Professor Trail adds to the above description that "in the autumn
thicker-walled resting spores are formed singly in the cells of the food
plant."

Plate LXXX2. jig. 5. Sorus of Synchitriwn Taraxaci X 200. Figs. 6,
7, cells with contents converted into zoogonidia, X 400. Fig. 8, free
zoogonidia, X 400 ; after Woronin.

Synchitriuxn anemones. Woron. Bot. Zeit, XXVI., p. 100, t. 2,

/. 8-10.

Forming dark violet, or almost black, hemispherical warts,
the size of a pin's head, which are gregarious, and sometimes
confluent. In the centre of each is a spherical cellule, the wall
of which is dark brown and warted.

Dothidea anemones, DC. Fl. Fr. vi., 143.

Sphceronema anemones, Libert. Crypt. Ard., No. 167.

Septoria anemones, Fuckel Fung. Rhen., No. 518.

Chytridium ? anemones, D.By. & Wor. Beitr. p. 29.

Parasitic on the leaves of Anemone nemorosa.

Plate LXXXII. jig. 7. Portion of leaf with Synchitrium nat. size.
Fig. 8, persistent spore- cell in situ X 200. Fig. 9, persistent spore-cell
free X 320 ; after Woronin.

Synchitxium mexcurialis. Fckl. Fungi Rhen., No. 1067.

Tubercles confluent on the nerves of the leaves, hemispheri-
cal, greenish, depressed above ; umbilicated ; sori oblong, grey,
zoogonidia globose, uninucleate, hyaline.

SIZE. Sporangia echinulate '03-'04 mm.

Schrcet. in Cohn's Beitr. p. 40. Grevillea ii., p. 162.

Parasitic on leaves of Mercurialis perennis. April,

Plate LXXXII. Jig. 1. Section of wart with persistent spore-cell.
Fig. 2, persistent cell. Fig. 3, same with contents polygoiially divided.
Fig. 4, sporangia escaping X 160. Fig. 5, sporangia X 320. Fig. G, free
zoospores X 320 ; alter Woronin.

202 CHYTRIDIE^E.

GENUS 80. CHLOROCHYTRIUTO. Colin.

Plant endophytic ; green, unicellular ; cells globose, or some-
what irregularly bi-, tri-, or multi-lobed ; densely filled with
chlorophyll, first dividing into large segments, and then these
giving origin to innumerable pyriform zoospores, which escape
through a tubular process.

Chloxochytxium Lemnse. Cohn. Beitr. I., 87.

The zoospores, impinging on the epidermis of the duckweed
at the junction of two cells, after germination commences a tube
is produced, which, entering between the walls of the dissepi-
ments, proceeds as far as the mesophyllic parenchyma, growing
into the intercellular spaces, and forms either a globose,
elongated, or irregular-shaped cell.

SIZE. Adult cell O-'l mm. diam.

Wright in Trans. Roy. Irish Acad. xxvi. (1877), p. 13.
Archer in Quart. Journ. Micr. Sci. xv. (1875), p. 104.

Living in the thallus of Lemna trisulca. Westmeath (Ire-
land).

Cohn says of this species : " Its zoospores attach themselves to the
thallus of the duckweed often in hundreds. They force tbeir way
through between the epidermal cells, assuming, as the foremost portion
gets into the hypodermal tissues, a more or less figure of eight-shaped
form : the foremost portion, getting into an intercellular space, dilates ;
the portion that has not entered remains unexpanded, and forms a
colourless nipple-like projection ; the portion within the thallus expands
to many times its original diameter, sometimes dilating and filling up an
intercellular space, at others distorting the subadjacent cellular tissue,
and frequently itself becoming variously distorted. The cell wall becomes
thicker, even laminated ; the chlorophyll contents get dark and dense,
and the cell becomes of a dark, nearly opaque green ; sometimes starch
granules are seen. The cell contents become segmented, breaking up into
a number of pear-shaped zoospores, which escape through the nipple-like
projection ; their actual exit was not seen, nor was the number or position
of the cilia observed. Of the zoospores, many never succeeded in pene-
trating the epidermis of the duckweed upon which they alighted, and
such would remain as minute colourless pin's heads on the surface of the
Lemna. Some would linger within the mother cell, and might possibly
be resting spores." — Abstract by Prof. Perceval Wright, loc. cit.

Plate LXXXI. fig. 9. Chlorochytrium Lemnte parasitic on duckweed.
Zoospores located in intercellular spaces X 600. Fig. 10, in a more
advanced stage x 600. Fig. 11, free zoospores x 600. After Cohn.

CHROOCOCCACE^E. 203

CLASS II. PIIYCOCHROMOPHYCE^.

Plants one or many celled, living in water, or enclosed in a
maternal jelly when out of it, mostly in families formed from
successive generations of cells. Cell membrane (Cytiodenn)
not siliceous, combustible. Cell contents (Cytioplasiii) a brown,
olivaceous, or fuscous endochrome, destitute of nucleus, and
usually without starch granules.

Propagation by division, and by immovable gonidia, or
quiescent spores.

ORDER I. CYSTIPHOHJE.

Unicellular plants. Cells spherical, oblong, or cylindrical
enclosed in a tegument, associated in families surrounded by a
universal tegument, immersed in a more or less liquid or firm
mucilage, variable in colour, for the most part irregularly dis-
posed. Division of the cells taking place in one, two, or
three directions alternately. Propagation by quiescent gonidia.

Fo3cundation unknown.

FAMILY I. CHROOCOCCACEJ3.

Thallus mucous or gelatinous, amorphous, enclosing cells and
families irregularly disposed.

It ma)'- be urged that, as many of the species included in this family,
as well as in the analogous Palmellacece, are only conditions of higher
forms, they should not have been inserted. In the preparation of a Flora
of this kind, however, we are of opinion that whilst the life history of
these forms is so imperfectly known, we should not have been justified in
excluding them.

GENUS 81. CHROOCOCCUS. Nageli. (1849.)

Cells globose, or more or less angular from mutual pressure,
solitary, or associated in globose cubical or amorphous families,
free (not involved in a mother-cell). Cell membrane in most
cases thin, homogenous, achromatic, often confluent in a more
or less firm jelly ; cell contents verdigris, or pallid blue green,
not rarely yellow or orange. Propagation by division alter-
nately in three directions.

204 CYSTIPHOR.E.

Chroococcus cohaerens. Nag. fide RaWi.

Cells oblong, twin, or in fours, with a distinct hyaline ellipsoid
tegument ; cell-membrane thin, achromatic ; cell-contents
homogenous, or slightly turbid, blue-green.

SIZE. Cells -003-'006 mm. diam. Families of 2-4 indivi-
duals.

Rabh. Alg. Eur. ii., 30. Kirch. Alg. Schles. 261.

Protococcus cohcerens, Kutz. Spec. 197. Tab. Phyc. 1, t. 5.

Pleurococcus cohcerens, Breb. in Meneg. Nost. Ital. 35, t. iv.,
f. 3.

On damp walls and flower pots.

Plate LXXXI1I. fig. 1. Cells magnified 400 diam.

Chroococcus turgidus. Nag. Einz. Alg. 2^ 46.

Cells spherical, oblong-ellipsoid, or more or less angular from
compression, single, twin, ternate, or quaternate (rarely 8),
associated in families, tegument thick, usually evidently lamel-
lose, colourless. Cell-membrane thin ; cell contents bright
verdigris green and homogenous, at length becoming brownish
and granulated.

SIZE. Cells -013--025 mm. diam. Families of 2-4.

Rabh. Alg. Eur. ii., 32. Kirch. Alg. Schles. p. 262.

Protococcus turgidus, Kutz. Tab. i., t. 6, f. 1.

Hcematococcus binalis, Hass. Alg. p. 331, t. 82, f. 2.

In swampy places and on moist rocks.

Not at all uncommon ; often mixed with other algee. Easily dis-
tinguished by its size.

Plate LXXXIII. jftff. 2. Cells magnified 400 diam.

GENUS 82. GLCEOCAPSA. Kutz. (1843.)

Cells spherical, either single or numbers, associated in
families, the single cell included in a vesiculiform tegument,
this cell undergoing division into two daughter cells. Each
has a distinct tegument, the whole being surrounded by the
tegument of the mother cell. This process is repeated again
and again, the original tegument remaining and surrounding
the family thus formed. Cell membrane thick, often very thick,
equalling or exceeding in diameter the cavity of the cell;
colourless or coloured, mostly lamellated, strata not tin-
frequently separating. Cell contents of various colours,

CHROOCOCCACE^E. 205

semgirious, bluish green, steel-blue, reddish, yellowish, fuscous,
&c. Division of the cells in three directions, the last genera-
tion of the cells smaller than the early ones. — Rabh. Alg. Eur.
ii., 34.

Glaeocapsa coracina. Kutz. Phyc. Gen. 174, t. 6, /. 1.

Thallus crustaceous, very black, lubricous ; single cells
sphserical, small, tegument very pale violet, distinctly lamel-
lose, cell contents homogenous blue-green.

SIZE. Cells -0033--004; with envelope -OOG-'OH mm.
Families •009-'075 mm. diani.

Rabh. Alg. Eur. ii., 35. Kirch. Alg. Schles. p. 258.

Microcystis atrovirens, Meneg. Nost. Ital. 76, t. 10, f. 1.

On rocks, and on boggy ground amongst moss.
Plate LXXX1II. fig. 3. Cells magnified 400 diam.

Glaeocapsa atrata. (Autz.) Ralh. Alg. Eur. IT., 35.

Thallus crustaceous, mucous, black ; cells sphserical small,
tegument very thick, hyaline, homogenous, two or three times
broader than the central cell, cell-contents pale verdigris green,
rather granulated.

SIZE. Cells -0035--0045 mm., with envelope -009--014 mm.
Families '01-'08 mm.

Nag. Einz. Alg. t. 1, f. 1. Kirch. Alg. Schles. p. 258.

Microcystis atra, Kutz. in Linn, viii., 375.

On rocks in mountain regions.
Plate LXXXIIL fig. 4. Cells magnified 400 diam.

Glaeocapsa livida. (Carm.} Kutz. Tab. i., t. 21, /. 5.

Thallus mucous, rounded lobate, broadly expanded hyaline
dingy green, or olive brownish, cells very minute, tegument
pale bluish, hyaline, cell contents solid dark blue-green.

SIZE. Cells -003--006 mm.; with envelope -006--0078 mm.
Families -016--05 mm.

Eabh.Alg. Eur. ii., 36. Kirch. Alg. Schles. 258.

Palmella livida, Carm. in Grev. Fl. Edin. ; Eng. Fl. v., 397.
Harv. Man. 178.

Hcematococcus lividus, Hass. Alg. 332, t. 82, f. 5.

Microcystis livida^ Meneg. Nost. 74, t. 9, f. 2.

On naked ground, or amongst moss and lichens, rarely on
rocks, on mountainous moors.

" Covers the overhanging limestone rocks to a great extent, sometimes
as much as several hundred yards together. When fresh it looks like a
blackish brown, gelatinous substance, giving the rocks on which it grows

206

the appearance of being covered with pitch ; on places where it becomes
dry by exposure to the sun it is very friable, and on being touched
crumbles down to a powder." — Moore, in Hass. loc. cit.

Plate LXXXIII.fig. 5. Glfsocapsa livida, drawn from Carnuchael's
original specimen X 400.

Glseocapsa caldarioxuxn. Eabh. Alg. En?: 37.

Thallus irregular thick gelatinous, pale yellowish, cells soli-
tary, globose or rather elliptical, tegument spherical or elliptic,
colourless lamellose, lamellae often diffuse, the externally one
manifestly diffluent ; cell-contents homogenous, or rather
granulose, pale blue -green.

SIZE. Cells -003--006 mm. with envelope -019--04 mm.

Glceocapsa montana var. caldarii, Suringar Obs. 54, t. 4, f.
E. Kirch. Alg. Schles. 257.

On walls, flower-pots, glass, &c., in conservatories and green-
houses.

Plate LXX1IL fig. 6. Cells magnified 400 diam.

G-lseocapsa polydexmatica. Kutz. Tab. 1, t. 20.

Thallus gelatinous, more or less compact, dirty green, or olive
becoming brownish; cells small sphaerical, tegument very thick,
hyaline lamellose, lamella numerous, concentric, firm ; cell-
contents verdigris green, almost homogenous.

SIZE. Cells -003--0045 mm. ; with envelope '023 mm.
Families '05 mm.

Rabh. Alg. Eur. ii., 37. Kirch Alg. Schles. 257.

Microcystis rupestris, Men eg. Nost. 72, t. 9, f. 1.

Hcematococcus rupestris, Hass. Alg. 326, t. 82, f. 1.

On moist rocks.

" Frond hyaline, gelatinous, yellowish green, easily broken up, about
an inch in diameter, shapeless, rough, pellucid, more or less dense in the
centre and elevated ; when dried collapsed, blackish, cartilaginous,
fragile. Subjected to the microscope it appears constituted of hyaline
subsphaerical vesicles, enclosing yellowish green, spherical or slightly
oblong globules usually undivided. Solitary globules, magnified with
glasses less powerful are seen free and naked ; by means of a more
powerful microscope, almost all are perceived to be clothed with a proper
cyst, larger vesicles enclose smaller, and the whole frond appears areo-
lated, the hollow areolre containing solitary or binate globules. The
vesicles general as well as partial, duplex, triplex, or multiplex, and that
without any perceptible order, commonly present concentric circles,
generally approximated, evident to the light." — Menegliini.

Plate LXXX.lII.fig. 7. Cells magnified 400 diam.

Glaeocapsa quaternata. Kutz. Tab.i., t. 20, /. 1.

Thallus mucous, effused, dirty green, becoming reddish
brown; cells usually sphserical, single or twin or qtiaternate

CHROOCOCCACEJI. 207

(rarely 6-8) in families, tegument narrow, lamellose, achromatic,
rounded or oblong ; cell-contents verdigris green, homogenous,
or delicately granulated.

SIZE. Cells -0032--0045 mm. ; with envelope -007--011 mm.
Families -011--022 mm.

Rabh. Alg. Eur. ii., 37. Kirch. Alg. Schles. 257.

Coccochloris quaternata, Breb. MSS.

On rocks or moist ground (Scotland).
Plate LXXXIII. fig. 8. Cells magnified 400 diam.

Gleeocapsa arenaria. (Hass.) EaWi. Alg. Eur. I., 39.

Thallus mucous, coherent, somewhat olive-coloured ; cells
large sphserical, tegument thick oblong or almost sphaerical,
colourless, lamellose ; lamellae diffluent, cell-contents verdigris
green then brownish, distinctly granulated.

SIZE. Cells -0033--005 mm., with envelope '006--014 mm.
Families '04 mm.

Rabh. Alg. Eur. ii., 39.

Hcematococcus arenarius, Hass. Alg. 330, t. 76, f. 10.

In springs and thermal waters.
Plate LXXXIV. fig. 1. Cells magnified 400 diam.

Glaeocapsa aeruginosa. (Carm.) Kutz. Tab. I., t. 21, /. 2.

Thallus crustaceous, grumous, or cartilaginous, glaucous
green ; cells small sphserical, tegument thick colourless, indis-
tinctly lamellose, externally not rarely angular, cell-contents
verdigris green, homogenous.

SIZE. Cells -0022--003 mm. with envelope '0044--0088 mm.
Families -016-'05 mm.

Rabh. Alg Eur. ii., 39. Kirch. Alg. Schles. 258.

Palmella ceruginosa, Carm. MSS.

Hcematococcus centgi?iosus, Hass. Alg. 333, t. 82, f. 3.

On limestone and other rocks.
Plate LXXXIV. fig. 2. Cells and families magnified 400 diam.

Glaeocapsa magma. {Breb.) Kutz. Tab. I., t. 22, f. 1.

Thallus grumous, rather crustaceous, purple brown, blackish
when dry ; cells for the most part spha?rical, tegument lamel-
lose intense purple or coppery- brown, usually not pellucid,
external stratum very broad, globose, paler or colourless, soon
diffluent ; cell-contents verdigris green, granulose, often becom-
ing brownish.

SIZE. Cells -0045--007 mm., with envelope -006--012 mm.

2 o

208 CYSTIPHOR.fi.

Babh. Alg. Enr. ii., 42. Kirch. Alg. Schl 250.

Sorospora montana, Hass. Alg. 309, t. 79, f. 1.

Palmella mmitana, Ag. Syst., p. 18. Eng. Fl. v., 396. Eng.
Bob. ii., t. 2554. Harv. Man. 179.

Protococcus magma, Meneg. Nost. p. 43.

Viva montana, Lightf. Fl. Scot. 973. Hull. Br. Fl. 314.
Eng. Bot. i., t. 2193. Hook Scot, ii., 91. With. AIT. iv.,
122.

Merrettia alpicola, Gray Arr. i., 349.

"Mountain dulse," of the Scotch.

On moist rocks.

" On the mountains of Arran, this lies unattached among loose wet
stones, covering them in a straggling manner to a considerable, extent.
Each frond is 1-1^ inch, in diameter, flatfish, somewhat orbicular,
between coriaceous and gelatinous, when dry almost horny, of a deep but
dull purple colour, much lobed and curled like some Gyroplioroe, filled
with crowded clusters of granules, which, if minutely examined are found
to he mostly arranged in fours " —Hooker.

In Scotland it is called Mountain Dulse, and, according to Lightfoot.
" the Highlanders wash it and rub it between their hands into some
water, so as to make a thin pulpy mixture, with which they purge their
calves."

Plate LXXX17. Jig. 3. Cells and families magnified 400 diain.

Glaeocapsa rupicola. Kutz. Spec. p. 221.

Thallns black, then fuscous or brown, crustaceous, thin, rather
grnmous, cells small, sphaerical, tegument narrow, not lamellose,
fuscous then rusty-brown, for the most part associated in fours,
rarely in twos ; outer tegument broad, very pale, globose, enclos-
ing numerous smaller families, soon diffluent ; cell-contents pale
verdigris green, or rusty brown.

SIZE. Cells -0033--005 mm. Families -07 mm.

Rabh. Alg. Enr. ii., 43.

On rocks amongst moss (Scotland).
Plate LXXXiy. fig. 4. Cells and families magnified 400 diam.

Glaeocapsa sanguinea. (Ay.) Kutz. Tab. i., t. 22.

Thallus effused, gelatinous, thin, blood red or thicker and
somewhat crustaceous, then becoming blackish brown; cells of
medium size, spherical, tegument intense blood red, not lamel-
lose, in the middle pale red, the extreme outer colourless or
nearly so, very broad, globose or angular ; cell-contents pale ver-
digris green, granulose.

SIZE. Cells with envelope -0037->009 mm. Families to
•14 mm.

209

Kabh. Alg. Ear. ii., 43. Kirch. Alg. Schles 259.
Palmella sanguined, Ag. Syst. p. 15.

Hcematococcus sanguineus. Ag. Icon. t. 24. Harv. Man. p.
181. Hass. Alg. 329, t. 79, f. 2. Eng. Fl. v., p. 395.

On rocks.
Plate LXXXV. fig. 1. Cells and families magnified 400 diam.

Giaeocapsa Ralfsiana. (Harv.) Kutz. Tab. I., i. 23.

Thallus gelatinous, compact, dark purple brown ; cells of
medium size, sphserical, tegument very thick, opaque, and in-
tense purple, the outer very broad, usually angular irorn mutual
compression, almost colourless, rarely diffluent, enclosing
smaller families of 2, 4, 6, 8 ; cell-contents granulated, pale ver-
digris green.

SIZE. Cells with envelope 'Ol-'Ol? mm. Small families
•022--04 mm. Large families, to '17 mm.

Kabh. Alg. Eur. ii., 44.

Sorospora Ralfsii, Hass. Alg. 310, t. 79, f. 3.

Palmella Ralfsii) Harv. Man. 179.

Amongst moss and lichens.

" Thallus a few lines in diameter, gelatinous, somewhat areolate, or as
if composed of numerous small vesicles massed together, each of which
contains 2-4 or 8 large blood red granules, which are much larger and of
a far deeper colour than those of G. magma.'" — Harvey.

Plate LXXXV. Jig. 2. Cells and families magnified 400 diam.

Giaeocapsa Shuttleworthiaiia. Kutz. Tab. I., t. 23, f. 1.

Thallus gelatinous, rather hard, compact, dark rufous brown ;
cells small spluerical, tegument very thick, many times broader
than the central cell, globose, intense orange red, the outer glo-
bose or angular, homogenous, pale orange, or (rarely) colour-
less, all, except the inner, soon diffluent ; cell-contents pale
verdigris green.

SIZE. Cells with envelope '0075-013 mm. Families -035
mm.

Kabh. Alg. Eur. ii., 44. Kirch. Alg. Scliles. 259.

On moist rocks, and amongst moss.
Plate LXXX7. fig. 3. Cells and families magnified 400 diam.

Giaeocapsa xupestxis. Kutz. Tab.Pliyc. i., t.22,f. 11

Thallus dark brown, crustaceous, rather hard ; cells rather
large, sphserical ; tegument very thick, laniellose, yellow or

210 CYSTIPHOR^E.

golden brown, the outer permanent, yellowish or becoming pale ;
cell-contents verdigris green, granulose.

SIZE. Cells '006-'C09 mm. with envelope. Families
•015--075 mm.

Kabh. Alg. Eur. ii., 47. Kirch. Alg. Schles. p. 260.

On rocks.
Plate LXXXIV. fig. 5. Cells and families magnified 400 diam.

GENUS 83. APHANOCAPSA, Nag. (1849.)

Cells spherical, with a thick, soft, colourless tegument, con-
fluent in a homogenous mucous stratum. Cell division as in
Gleceocapsa. — RaWi. Alg. Eur. n., 48.

Aphanocapsa virescens. (Hass.} Rdbli. Alg. Eur. n., 248.

Thallus gelatinous, more or less expanded, dirty green, or
olive, becoming brownish, cells of medium size, pale bluish-
green, solitary or in pairs, tegument scarcely visible. Cell
contents homogenous, sometimes with a central vacuole.

SIZE. Cells about -0055 mm. diam.

Sorosporium virescens, Hass. Alg. 310, t. 78, f. 8 a.

Aphanocapsa parietina, Nag. Einz. Alg. t. Ib, f. 1.

On stones, rocks, &c.

Plate LXXXVI. Jig. 1. Cells magnified 400 diam.

Aphanocapsa rivularis. (Carm.~) Rabli. Alg. Eur. n., 49.

Thallus hemispherical, gelatinous, tuberculose, often confluent,
asruginous-green, becoming brownish when dry ; cells spherical,
scattered, single or in pairs, tegument very thick, not lamellose,
colourless, soon diffluent. Cell-contents bluish-green, delicately
granular.

SIZE. Cells about '005--006 mm. diam.

Palmella rivularis, Carm. MSS. Harv. in Hook. Eng. Fl.
v., p. 397. Harv. Man. 177.

Coccochloris rivularis, Hass. Alg. 317, t. 78, f. 6 a, b.

On rocks and stones inundated, in mountain streams.

" Fronds one-fourth or half an inch in diameter, hemispherical, tuber-
cular, firmly adhering, sometimes cohering into a broad crust. Colour
vivid green." — Carmichael.

Plate LXXXFL fig. 2. Cells of A. rivularis, X '400.

Aphanocapsa Grevillei. (Hass.) RabJi. Alg. Eur. n., 50.

Thallus gelatinous, globose, densely aggregated, more or less
confluent, dirty green, from olive to brownish when dry ; cells

CHROOCOCCACEjE. 211

spherical or elliptic, rather crowded, single or in pairs, nestling
in a homogenous jelly, tegument quickly diffluent, cell-contents
blue-green, delicately granulose.

SIZE. Cells -0035--006 mm. diam.

Kirch. Alg. Schles. 261.

Coccochlons Grevillei, Hass. Alg. 318, t. 78, f. 7 a, b, 8.

Palmella botry aides, Grev. Crypt. Fl. t. 243, f. 2. Eng.
Fl. v., 396. Eng. Bot. ii., p. 207. Grev. Fl. Ed. 323. Mack.
Hib. 244.

Palmella Grevillei, Berkl. Glean, p. 16, t. v., f. 1. Harv.
Man. 177.

Botrydina Grevillei, Meneg. Nost. p. 47.

Byssus botryoides, Huds. Ang. 608. Lightf. Fl. Scot. p.
1006. Rehl. Cant. 447.

Cococliloris radicata, Johnst. Fl. Berw. ii., 262.

Olivia botryoides, Gray Arr. i., 349.

Byssus pulverulenta viridis, Dillen. Muse. 3, t. 1, f. 5.

Byssus botryoides saturate virens, Ray. Syn. 56, No. 5.

On damp heaths and moors.
Plate LXXXn.fig. 3. a, natural size ; b, cells magnified 400 diam.

Aphanocapsa depxessa. (Hass.) RaWi. Alg. Eur. n., 51.

Thallus somewhat hemispherical, depressed, gelatinous, green.
Cells sphserical or irregular, variable in size.

SIZE. Cells -0025--003 mm.

Palmella depressa, Berk. Glean. 19, t. 5, f. 4. Harv. Man.
178.

Coccochloris depressa, Meneg. Nost. 68. Hass. Alg. p. 316,
t. 78, f. 4 «, b.

Growing on an old pump, at Cotterstock, Northamptonshire,
constantly moistened with the drippings from the spout.

" Fronds bright yellow-green, gelatinous, subhemispherical, depressed,
crowded together, filled with more or less globose or angular very minute
granules." — Berkeley.

Plate LXXXV1. Jig. 4. a, plant natural size ; &, cells magnified 400.

GENUS 84. MICROCYSTIS. Kutz. (1833.)

Cells sphgerical, numerous, densely aggregated, enclosed in a
very thin globose mother vesicle, forming solid families, singly,
or several, surrounded by a universal tegument. Cell division
in three directions alternately.

This genus as defined by Eabenhorst (Alg. Eur. ii., 51) not appearing
to differ essentially from Anacystis, both are united in this work.

212 CYSTIPHOR.E.

XVXicrocystis protogenita. (Bias.) Eabli. Alg. Eur. n., 51.

Thallus membranaceous, thin, green; families small, angular
from mutual pressure ; cells small, spherical ; cell-contents
granular, pale blue-green.

SIZE. Families, -02 mm. Cells, -0015--002 mm.

Micraloa protogenita, Bias. Alg. Micr. t. xix. Meneg. Nost.
t. xiv., fig. 1 (partly).

In water long standing, stagnant ditches, amongst other
Alga3, &c.

Plate LXXXVI. fig. 5. Families magnified 400 diam.

XKicrocystis marginata. (Meneg?) Kirch. Alg. Schl. 255.

Thallus spha3rical, flattened, or orbicular and lens-shaped,
sometimes confluent, pale-green, colourless at the margin ; cells
minute ; cell contents blue-green, at length granular.

SIZE. Cells -003--004 mm. Families 'S--03 mm.

Anacystis marginata, Meneg. Nost. 93, t, 13, f. 1 , Kabh. Alg.
Eur. ii., 52.

In ditches, free swimming.

Plate LXXXVI, fig. 6. Families magnified 400 diam.

GENUS 85. CLATHROCYSTIS. Henfrey. (1856.)

Frond, a microscopic gelatinous body, at first solid, then
saccate, ultimately clathrate (fragments of the broken fronds
occurring in irregularly lobed forms) composed of a colourless
matrix, in which are imbedded innumerable minute cells, which
multiply by division within the frond as it increases in size. —
Quart. Journ. Micr. Sci., 1856, p. 53.

Clathrocystis aesruginosa. Henf. Micr. Journ. 1856, p. 53, f. 4,

f. 28-36.

Fronds floating in vast strata on freshwater pools, forming a
bright green scum, presenting to the naked eye a finely granular
appearance ; when dried, appearing like a crust of verdigris ;
cells minute.

SIZE. Fronds -03--13 mm. ; cells '0025--0035 mm.

Kabh. Alg. Eur. ii., 54. Kirch. Alg. Schles. 254.

Microcystis ceruginosa, Kutz. Tab. i., t. 8.

Polycystis ceruginosa, Kutz. Spec. 210.

On fresh water lakes.

"The smallest fronds met with are usually roundish or ellipsoidal.
When quite young they appear to be solid, but as they grow by the multi-
plication of the internal cells and the secretion of gelatinous matter, the
expansion takes place chiefly near the periphery, so that the frond becomes
a hollow body. The walls of the sac then give way, and, as the expan-

CHROOCOCCACEJ]:. 213

sion proceeds, orifices are formed in different parts, until the whole
becomes a coarsely latticed sac or clumsy net of irregularly lobed form.
Then this becomes broken up into irregular fragments of all shapes and
sizes (giving the stratum, a granular appearance to the naked eye), each
of which recommences the expanding growth, and becomes a latticed
frond. The internal cells are very minute, but have a distinct margin
with internal granules. They multiply by dividing into two and four.
The gelatinous frond always presents a transparent border or peripheral
stratum, destitute of green cells ; but no boundary membrane exists, the
surface exhibiting a softened or half-dissolved aspect. On the approach of
winter the fronds ceased to increase, and by degrees most of the gelati-
nous masses faded to a light brownish tint, swelled up and settled to the
bottom of the water in light flocculent clouds. They appear to become
half-dissolved, and to allow the green cells to become free, as many of the
latter were found free, adhering to the sides of the vessel. Perhaps these
reproduce the fronds in the next season. No zoospores were ever de-
tected."— Henfrey.

Clathrocystisroseo-persicina,, Colin., is already included in this work, as
Pleurococcus roseo-ptrsici/tus, pi. 2, fig. 0.

Plate LXXXVL fig. 7. a, Thalli magnified 200 cliam. ; 6, cells mag-
nified 400 diam.

GENUS 86. CffiLOSPHJERIUM. Nag. (1849.)

Thalliis globose, small, vesicular, hollow, composed of small
cells, which are associated in families at the periphery, im-
mersed in a mucous stratum, formed from the speedily confluent
teguments. Increase by division of the cells in all directions,

Ccelosphaerium Kutzingianuxn. Nag. Elm. Alg. p. 54, t. 1 c.

Families sphasrical. Cells stibglobose, geminate, or quater-
nate, loosely disposed ; cell-contents blue-green, delicately
granulose.

SIZE. Cells '002-'005 mm. ; families '06 mm. and more.

Rabh. Alg. Eur. ii., 55. Quart. Journ. Micr. Sci. 1869, p.
197. Kirch. Alg. Schles. 254.

In ponds, meres, &c.

Plate LXXXVII.fig. 1. Families magnified 400 diarn.

GENUS 87. GOMPHOSPHffiRIA. Kutz. (1836.)

Cells wedge-shaped, peripherical, 2-4-8 associated in radiating
families nestling in jelly, covered with a tegument, and forming
a solid globose free-swimming thallus. Cells dividing alter-
nately in three directions.

Gomphosphaeria aponina. Kutz. Tab. I., t. 31, f. 3.

Thallus microscopical, blue-green, often becoming pale, tegu-
ment colourless, rather thick and somewhat lamellose, central
cells smaller, cell-contents verdigris or pale blue-green,

214 CYSTIPHOR^:.

SIZE, Cells '004 mm. cliam. to '01 mm. long ; families "05 mm.
Rabh. Alg. Eur. ii., 56. Kirch. Alg. Schles. 255.

In ditches.

Plate LXXXVII. fig. 2. Families magnified 400 diam. ; a, J, c, d,
cells in various stages of subdivision, further magnified — after Eeinsch.

GENUS 88. MERISIYIOPEDXA. Hey en. (1839.)

Cells globose, at the time of division oblong, rather thick,
teguments confluent, 4-8-16-32-64-128 associated in tabular
families of a single stratum, forming a quadrate, plane, free-
swimming thallus.

Goebel has observed the formation of zoospores in this genus, See
" Botanische Zeitung," 1880, p. 490.

n/Ierismopedia violacea. Kutz. Spec. 472.

Thallus mucous, colourless, or nearly so, indefinite, families
small, composed of 4-32 remote very minute cells ; cell-contents
homogenous, violet.

SIZE. Cells '001--0015 mm.; families *015 mm.

Rabh. Alg. Eur. ii., 57. Kirch. Alg. Schles. 254.

In ponds, ditches, &c., amongst other Alga3.
Plate LXXXV1I. fig. 3. Families magnified 400 diam.

lYIerismopedia glauca. Nag. Einz. Alg. t. 1, D. 1.

Thallus more or less limited, glaucous green, margin slightly
sinuately crenate ; families composed of 16-48-64 (rarely more)
oval or globose cells ; cell-contents pale blue-green.

SIZE. Cells '003-'005 mm. ; families -04-'05 mm.

Rabh. Alg. Eur. ii., 56. Kirch. Alg. Schles. 253.

Gonium glaucum, Ehrb. Infus. 56, t. 3, f. 5.

In stagnant water.
Plate LXXXVII. fg. 4. Families magnified 400 diam.

IVIe:rismopedia punctata. Meyen in Wirgm. Arch. 1839, p. 67.

Thallus less limited, almost colourless, for the most part com-
posed of 4-64 remote cells ; cell-contents pale blue-green.

SIZE. Cells '033 mm. ; families '06 mm.

Kutz. Tab. i., t. 38, f. 3. Rabh. Alg. Eur. ii., 57. Kirch.
Alg. Schles. 254.

In stagnant water.
Plate LXXXVII. Jig. 5. Families magnified 400 diam.

CIJROOCOCCACE^E. 215

Merismopeiia ventriculi. Rolin Veg. Par. t. I,/. 8.

Thallus mucous-membranaceous, firm, -whitish or yellowish ;
families composed of numerous cells (8-4096) ; cell-contents
pale bluish.

SIZE. Cells -008 mm. cliam. ; families -03--05 X -016--02 mm.

Rabh. Alg. Eur. ii., 58. Ktichenm. Par. p. 13, t. 1.

Merismopcedia Goodsiri, Husem. de Anim. p. 13.

Sarcina ventriculi, Goodsir in Edin. Mecl. and Surer. Journ.
1842, p. 430, t. 57. Welcker in Quart. Journ. Micr. Sci. viii.,
p. 163.

In the human stomach, &c.

Doubtfully included here. Recently authors have classed it with
Schizomycetes in preference to Algre.

Plate LXXXV1I. fig. 6. a, cells magnified 400, 6, cells very
highly magnified. After Robin.

Merismopedia renis. (Hepw.) Rabli. Alg. Eur. n., 59.

Families composed of from 8 to 64 cells.
SIZE. No dimensions given.

Sarcina renis, Hepworth in Micr. Journ. v. 1857, p. 1,
with woodcut.

In the human kidneys.

This very obscure organism, like the last, is included here with con-
siderable doubt. It may be said that nothing more is known of it than
the meagre diagnosis above given. Sarcina ossium, Stephens, Ann. Nat.
Hist. ser. 2, vol. xx., p. 514, is equally uncertain.

Plate LKXXV11. Jig. 7. Cells very considerably but indefinitely mag-
nified. After Hepworth.

GENUS 89. TETRAPEDIA. Reinsch. (1867.)

Cells compressed, quadrangular or triangular, equilateral,
becoming subdivided into quadrate or cuneaie segments, or
rounded lobes, either by deep vertical or oblique incisions, or
by wide angular or rounded sinuses.

" Amongst unicellular Algse falling under the class ChloropJiyttaceee,
forms with specially figured cells — that is, otherwise than globular, ellip-
soidal, or cylindrical, with more or less abruptly or broadly rounded ends
— are, as is well known, numerous ; but amongst such plants belonging
to the class Pkycochromacefs , so frequently found in the same situations
associated with the foregoing, so far as I am aware, not until recently has
attention been drawn to any examples of a specially figured outline.

" It does not appear, until the genus Tetrapedia was founded by Professor
Reinsch for two new and singular exceedingly minute chroococcaceous
forms, that examples of specially figured forms were known in this family
of Algae.

2 H

216 CYSTIPHOR.E.

" So far as our acquaintance with these little Algee reaches, there appear
to exist four (if not five) distinct, yet kindred forms of figured ' Chroo-
coccaceae ' — their remarkable shapes preclude their being regarded as
' Lichen-gonidia,' but whether mature plants or stages in the growth of
any more complicated structure remains a problem. Ours are at least
forms which here and there recur, and one can at once recognise them as
always offering the same charactersitics and as maintaining their apparent
individuality. Whether they are ' species ' or not, it may be a matter
of convenience, should observers meet them elsewhere, and be able to
throw a light upon them, to have at least a means of their recognition ;
for these reasons it occurs to me as desirable to record them under
Reinsch's genus." — W. Archer in Grevillea I., p. 44.

Tetrapedia Crux -Michael! . Eeinsch Alg. Mitt. Frank.

Cells quadrate, lateral margins entire, with two shallow con-
cavities, each extending half the length of the side, thus pro-
ducing an obtuse-angled central prominence, deeply incised at
the angles, incisions diagonal, rectilineal, deep, acute below,
slightly expanding upwards, thus bisecting the angles, and
dividing the cell into four broadly cuneate segments, the upper
angles of which are subacute (the incisions ultimately com-
pleted, and the cell breaking up ?) ; in side view lanceolate,
ends acute.

SIZE. Cells -008--012 mm. diam.

Archer in Grevillea i., p. 45. Eeinsch Algenflora, t. i., fig. 6.

In running water (very scantily) near Mullingar, Co. West-
meath, Ireland.

Plate LXXXVIL fg. 8. Cells magnified 600 diam.

Tetrapedia Reinschiana. Archer in Grevillea I., p. 46, t. 3, f.

11-13.

Cells quadrangular, two opposite margins excavated by a
wide triangular sinus, thus subdividing the cell into two broadly
cuneate segments connected by a wide isthmus, and somewhat
convex on their lower margins ; the other two opposite margins
of the cell, that is the upper margins of the segments, very
slightly concave at the middle, somewhat raised towards the
acute outer angles ; in side view oblong, constricted at the
middle, ends rounded.

SIZE. Largest cell 'OOTS-'Ol mm. diam.

In moor pools, Co. Dublin and Wicklow.
Plate LXXXril. fig. 9. Cells magnified 600 diam.

Tetrapedia setigera. Archer in Grevillea i.,p. 46, t. 3, fig. 14-17.

Cells triangular, the lateral margins somewhat deeply ex-
cavated by a broad rounded sinus dividing the cell into three

CHROOCOCCACExE. 217

lobes, rounded at the ends, and each terminated by a very
delicate straight bristle, in length about equal to the diameter
of the cell ; in side view oblong, somewhat inflated at the
middle at each side, ends round, and each seen tipped by the
bristle.

SIZE. Cells without bristles -0062--0075 mm., including the
bristles '016--02 mm., from end to end.

In moor pools, Co. Dublin and Wicklow.

Plate LXXXVIL fig- 10. Cells magnified about 600 diam. After
Archer.

GENUS 90. SYNECHOCOCCUS. Nag. (1849.)

•

Cells oblong, usually single, sometimes 2-4 connected in a
series constituting a family. Cell membrane thin, cell-contents
blue green ; now and then yellow or pale orange. Tegument
absent. Division in one direction only.

Synechococcus crassus. Archer Micr. Journ. 1867, p. 87.

Cells broadly elliptic, about one half longer than broad ; cell
wall very thin.

In shallow pools. Bray's Head, Ireland.

Larger than the largest of Nageli's species (S. ceruginosus*), from which
it is also distinguished by its elliptic or egg-shaped cells, somewhat
narrowing towards the gradually rounded ends, and not cylindrical, with
rounded truncate ends.

No figures or measurements of this species have been published, and
only the bare description reproduced above.

GENUS 91. GL<EOTHECE. Nay. (1849.)

Cells cylindrical-oblong, rounded at the ends ; division trans-
versal in one direction. Other characters as in Glceocapsa.
Tegument very thick, lamellose.

Gloeothece cystifeira. (Hass.) Ralli. Alg. Eur. II., 61.

Cells oblong-cylindrical, 2-4 associated in families ; involved
in a special universal tegument which is globose or oval, 1^-3
times as long as bread. Coil-contents verdigris green.

CYSTIPHOII.E.

SIZE. Cells -004- 005 mm., with tegument '008-' 01 2 mm.
Families -025-'045 mm.
Kirch. Alg. Schles., 251.

Coccoch Ion's cystifera, Hass. Alg. 441, t. 103.
Glceothece devia, Nag. Einz. Alg., t. 1, f. G. 3.

On rocks.

Plate LXXXVI11. fig. 1. Cells and families magnified 400 diam.

Gloeothece garanosa. R-xlh. Alg. Ear. n., 61.

Thallus compact-gelatinous, somewhat cartilaginous, granu-
lose, blue-green; cells oblong, twice as long as broad, usually
2-4 ^associated in families ; tegument very broad, many times
exceeding the central cell, distinctly lamellose, colourless or
nearly so, lamella? scarcely diffluent ; cell contents homogenous
or granose, pallid blue-green.

SIZE. Cells -014--018 mm. diam.

Palmella granosa, Berk. Glean, ii., p. 19, t. 5, f. 5.

Microcystis granulosa, Meneg. Nost. 85.

Hcematococcus granosus, Hass. Alg. 327, t. 81, f. 6. Jenner
Tunb. Wells, 90. Harv. Man. 181.

On mosses in swamps.
Plate LXXXVII1. fg. 2. Cells and families magnified 400 diam.

GENUS 92. APHANOTHECE. Nag. (1849.)

Differing from Gloeothece in all the teguments being usually
confluent. Cells oblong or subcylindrical. Cell-contents now
and then green, and then with difficulty distinguished from
Palmella.

Aphanothece prasina. Br. in Rabh. Alg. No. 1572.

Thallus gelatinous, more or less globose, tuberculose, the
size of a cherry, intense bright leek-green, sometimes confluent,
and then lobed, internally now and then interwoven with hyaline
threads; cells oblong or ovoid, 1-2 times longer than broad,
after division sphserical, tegument none, cell-contents verdigris
green.

SIZE. Cells -005--006 x -008--011 mm.

Eabh. Alg. Eur. ii., 65. Kirch Alg. Schlos. 252.

Coccochlcnis stagnina, West and Wall. Herb. Belg. 1099.

Aphanothece Mooreana, Lager. Sver. Algflora p. 44.

Palmella Mooreana, of this work p. 12, t. 5, f. 4.

In ditches and stagnant ponds.

CHROOOOCCACE.E. 219

We are of opinion that this and the next species, as well as the
Pcdmdla Mooreana figured on the 5th plate of this worU, are all one
species.

Plate L XXXV 111. fig. 3. a, natural size; b, cells magnified 400
diam.

Aphanothece stagnina. (Spr.) Ralli. Alg. Eur. n., 66.

Thallus gelatinous, oblong or elliptical, or nearly globose,
from the size of a pea to that of a cherry, pale hyaline verdi-
gris green ; cells oblong-oval, always smaller than in A.prasina,
±-1 times longer than broad, tegument none, cell-contents pallid
verdigris green.

SIZE. Cells -003--005 x '005--008 mm.

Kirch. Alg. Schles. 252.

Coccochloris stagnina. Spreng. Linn. Syst. iv., p. 372.

In stagnant water.

It is very doubtful whether any definite specific character can be found
to separate this from A. prasina. -As we have taken both from the
same pond, the difference in colour, and in the size of the cells, may be
assumed to be attributable only to difference in age.

Plate LXXXV1I2. fig. 4. #, natural size ; I, cells magnified 400
diam.

GENUS 93. HOMALOCOCCUS. Kutz. (1863.)

Thallus globose, gelatinous ; internal cells irregularly united
in a plane, oblong body, immersed in the gelatinous thallus.

Homalococcus Hassallii. Kiitz. Osterprocj. 1863, p. 6.

Thallus globose, soft, green, of the size of a pea or a hazel-
nut ; cells rounded or somewhat angular.
SIZE. Cells about '006 -'007 mm. diam.
Rabh. Alg. Eur. ii., 69.
Coccochloris hyalina, Hass. Alg. 315, t. 78, f. 2, a, b,

In stagnant water.

Plate LXXXV1II. fig. 5. a, natural size; b, cells magnified 400
diam. After Hassall.

220 NEMATOGEN.E.

ORDER II. NEMATOGENJE.

Plants multicellular, or pseudo-multicellular. Cells forming
a filament (Trichome), usually included in a tubular homogenous
or lamellate sheath (vagina). Filaments (Tricliomes*) either
simple or branched. — Ralli. Alg. Eur. n., 70.

Thuret unites Cystiphorce and Nematogence in one order under the
name of Cryptopliycece, representing the CystiplwreB by a Tribe called
Chroococcacecs and NematogencB by another Tribe termed Nostochinece, so
that really the difference is only one of name.

TRIBE 1. NOSTO CHINESE .

Trichomes simple or branched, with an obtuse, or acute and
setiform apex, either naked or enclosed in a sheath. Repro-
duction by fragments of the trie-home (liormogonia) which are
endowed with motion after separating from the mother plant
=Hormogonece. Thuret.

The Nostochinees, as interpreted by Messrs. Bornet and Thuret, are
subdivided into two groups, or sub -tribes.

Sub-Tribe 1. PSILONEM.E -with the filaments not attenuated at one ex-
tremity to a hair-like thread.

Sub-Tribe 2. TRICHOPHORE^E with the apex of the filament attenuated
to a hair-like extremity.

"Whilst the Chroococcacea? reproduce themselves by means of isolated
cells, the Nostochineae reproduce themselves by the fragments of fila-
ments (called liormogones), which are endowed with mobility after
separating themselves from the mother plant.

The filaments of Nostochinece are composed essentially of coloured
cells disposed in a row. This assemblage of cells isjspecially designated
a trichome. The trichome is either naked, or immersed in mucilage, or
enclosed in a sheath.

The presence or absence of heterocysts, their number, their situation
in the filament, are characters important to note, but which hitherto
have been much neglected. Easily recognized in the living plant by
their yellow colour from the other cells of the trichome, but sometimes
difficult to distinguish in dried specimens. In doubtful cases it is to be
remembered that the heterocjsts are united always Avith the sheath, and
if that envelope is defective in the other cells it will suffice to apply an
appropriate re-agent, such as potass, solution of iodine, &c., to obtain
evidence of their nature.

Sometimes the terminal cells of the trichome resemble the others (as
in Lynghya and Scytonema), sometimes the filaments are terminated by a
hyaline hair, elongated and deprived of its coloured contents, with a
diameter much less than the ordinary joints of the trichome (as Calo-
thrix, Rivularia, &c.). This distinction, which corresponds in another
instance to the principal growing point of extension of the filaments, is
very marked in the living state, and especially in individuals in full
vegetation. When, on the contrary, the plants are old, and the summit
broken and their hormogones dispersed, the complete filaments are
sometimes very rare, and must be sought with sonic perseverance.

NOSTOCEJ5.

221

Certain genera of Nostocliincce have the filaments constantly simple
(IVostoc, Analaena), others have the filaments frequently provided with
lateral branches (Scytonemece, Galotricliece). Sometimes these rami-
fications are normal, and result from the regular division of the
trichome (Rivtilaria, &c.), sometimes accidental and irregular. These
produce themselves when the trichome has broken, they grow and issue
laterally from the sheath, when it is not rare to observe the base of the
filaments of certain I/yngbya, or, again, when the hormogones are not able
to escape freely, they germinate in the interior of the sheath. Indeed,
it is very frequent that the germinations develope themselves in fila-
ments of all ages, but in that case the young filaments are not at all
enveloped by the general sheath of the filament that bears them.

Nostocs should be dried as quickly as possible after they are collected,
otherwise the trichomes escape and the sheaths are left empty. — Thuret,
in Ann. des Sci. Nat. 6 ser., Vol. i.,pp. 372-382 (1875).

The following is a dichotomous key to the classification as proposed by
M. Thuret:—

rFilaments tapering at the top into a hyaline

1 < hair ........

( Filaments always destitute of an apical hair .

("Filaments in which some of the cells change

2 -< into heterocysts ......

(.Filaments without heterocysts

o j" Filaments with lateral ramifications
Filaments without ramifications

/
\

Filaments immersed in a gela-
tinous mucilage of a determi-
4 NOSTOCE.E < nate shape ....

/Filaments free or immersed in an
v amorphous diffluent mucilage

C Filaments consisting of a coloured trichome

enclosed in a hyaline sheath
1 Filaments without a sheath distinct from the
[_ trichome .......

1. Heterocysts scattered in the trichome.

A. Spores originating in cells not adjoin-

ing the heterocysts ....

/3 Trichomes united in small float-
ing bundles ....

B. Spores originating in cells placed on

each side of the heterocysts

2. Heterocysts terminal (at both ends of the trichome).
C. Spores originating in cells placed just

12

2

3

7

10

4

Nostoc.
. 5

6
A. B. C.

Anabaena.
Aphanizomefion.

below the heterocysts

isc-like. Spores very
cysts placed at regular
.Cells longer than broad. Spores none

C Cells disc-like. Spores very prominent. He-
6 < terocysts placed at regular intervals .
(.

(Filaments spirally twisted .

•< -n • i -11 • / i

( -bilauieuts not spirally twisted

Cij lin drospermum.

ffbdularia.

Microohcete-.

Spirulina.

... o

222

NEMATOGENJ2.

<

( Filaments without a sheath distinct from
the trichome ......

/3 Filaments agglutinated in small float-
ing bundles .....

Filaments formed of one or several coloured
trichomes enclosed in a transparent sheath,
from which the trichomes emerge to repro-
i dnce new filaments .....

f Sheath containing several trichomes, at least
in the larger filaments ....

A. Filaments growing in scattered

creeping, erect, or floating wick-
like bundles ....

B. Filaments bundled, erect, growing

in small rounded tufts, or in felt-
like turf of indefinite extent.
Trichomes very slender

Sheath enclosing only a single trichome

A. Filaments simple, or only excep-

tionally exhibiting the beginning
of ramification where the tri-
chome issues from the side of
the sheath .....

(3 Filaments agglutinated in
wick-like bundles .

B. Filaments branched. Ramifications

prod need by the branching of the
trichome outside the sheath, very
irregular, and often geminate, as
in Scytonema ....

Trichomes of which the cells
only multiply in the direction
of the length of the filament

Trichomes of which the cells
multiply as well in the direc-
tion of the breadth of the
filament, at least where the
branches, which are always
produced by lateral multipli-
cation, originate

A. Cells of the trichome often gemi-
nate or ternate in consequence
of their lateral multiplication, or
even forming transverse several
celled bands. Sheath large. Cells
surrounded with a thick mem-
brane very prominent in the old
filaments. Hormogones origina-
ting in lateral branchlets formed
of a single row of cells

/3 Filaments of the hormogones
much slenderer than the
principal filament, and origi-
nating in unilateral tufts .

10 SCYTONEME.E 4

Oscillaria.
Trichodesmium.

• • • c7

A. B.

Microcoleus.

Inactis.
A. B.

Lyngbya.
Symploca.

Plectonema.

11

A. B.

Stiff onema.

Fiscliera.

NOSTOCE^.

223

B. Trichomes formed mostly of a
single row of cells. Sheath slen-
der. Aquatic plants looking like
Tolypothrix ....

/'Sheaths enclosing several trichomes

J Sheaths enclosing only a single trichome.

Ramifications produced by the deviation of

the trichome, which emerges from the side

V. of the sheath ......

A. Ramifications usually geminate, pro-

duced by a fold of the trichome
which ruptures outside of the
sheath, and gives birth to two
filaments given off at a right
angle. Heterocysts scattered
here and there in the trichome
without any evident relation to
the ramifications

£ Sheath very broad, forming
a transparent layer around
the trichome

7 Filaments agglutinated in
erect wick-like bundles

B. Ramifications rarely geminate, often-

times solitary, and originating at
a point where the continuity of
the trichome is interrupted by
heterocysts. One or several he-
terocysts placed directly above
each branchlet ....

12 CALOTRICHE^ 4

13 •(

Filaments agglutinated by a
more or jless firm mucilage.
Frond usually with a well de-
fined outline ....

Filaments free, growing in small
tufts, or forming a turf of
considerable extent

Heterocysts scattered. Ramifications very
irregular, arising from a fold in the tri-
chome, in the form of a V, where originate
two geminate filaments, distinct at the base,
but at a certain height transformed, for the
greater part, into a single filament, composed
of a single row of cells. Frond hollow, but
hard, folded and looking like a little Rivu-
laria

Heterocysts basal (placed at the base of the
principal filaments and branchlets). Ramifi-
cations produced by the transverse division
of the trichomes, the upper part of which
detaches itself and becomes a lateral branch-
let, while the lower part extending itself by
the side of its old tip makes a new extremity
similar to the first

Haplosiphon.
Cystocoleus.

A. B.

Scytonema.

Petalonema.
Symp liyosipkon.

Tolypothrix.

. 13

Calothrix.

Hormactis.

14

2 i

224 NEMATOGENJ3.

{

Spores originating in the lower part of the

trichome ........ GlccotricJia.

Trichomes never producing any spores . . . . .A.

A. Frond having a tendency to an
hemispherical or bladdery form.
Filaments exhibiting a disposition
to radiate from the base of the
frond Rivularia.

/3 Frond flat. Filaments erect,

parallel Isaetis.

Sab-tribe I. PSILONEMEJE. Filaments not attenuated into a

hair-like extremity.

FAMILY I. NOSTOCB^E.

Trichomes furnished with heterocysts, involved in a very
copious gelatin, more or less firm or diffluent, which is collected
into a variously expanded, or very often indefinite thallus, or
rarely with the mucilage quickly dissolved, subsolitary. — Borzi
A!g. Fico. p. 279.

GEXUS 94. NOSTOC. PaucJi. (1803.)

Thallus gelatinous or membranaceons, girt by a more or less
firm periderm, definite, globose, or variously expanded. Tri-
chomes flexuously curved, irregularly interlaced, now and then
vaginate, joints globose or elliptical, distinct, or more or less
closely connected. Heterocysts terminal or intercalated, larger
or equal to the other cells. Spores equal to the heterocysts, or
a little larger, green, becoming bluish, olivaceous, or yellowish
brown.

The Nostocs consist of a more or less firm jelly, in which beaded fila-
ments are imbedded, consisting of chains of small, somewhat globose
simple cells. These filaments or trichomes are usually surrounded by a
sheath, which is often so delicate as scarcely to be visible, or it is almost
obsolete. The frond or thallus may be globose, discoid, lotted, or
irregular, with a more or less distinct outer layer forming a, kind of
epidermis.

At irregular distances in the trichomes are larger cells, or heterocysts,
formerly regarded as spermatia, which differ in colour from the other
cells of the trichome. Individual cells become heterocysts uninfluenced
by any definite law at present demonstrated.

Increase in the filaments is caused by division of the cells in the longi-
tudinal direction, whereby the trichome is constantly being lengthened,
and new cells added, which lie in the mucilage.

Thuret has explained the process by which new plants originate from

NOSTOCE.K.

225

fragments of the trichome which he terms hormogones. The mucilage of
old plants being softened, portions of the threads which lie between the
heterocysts are detached and escape from the mucilage, whilst the hetero-
cysts remain behind. These escaped fragments become endowed with
motion, similar to that observed in Osdllaria. The cells of the horrno-
gone increase by division at right angles to the filament, and ultimately
separate longitudinally, becoming the centres of new plants.

Besides the reproduction by hormogones, certain special cells of the
trichome enlarge and become converted into spores, which germinate and
produce new plants, but no evidence of sexual reproduction has yet been
adduced.

Messrs Bornet and Thuret have subdivided the genus Nostoc into
eight groups, of which two are not represented in Britain. The
following is their synopsis, with the British species printed in small
capitals.

I. INTKICATA. Aquatic species. Fronds soft, gelatinous without deter-
minate form, often floating.

A. Trichomes forming irregular masses, de-

prived of the general mucilage.
Circumvolutions of trichome compact and

indistinct .......

Circumvolutions of trichome distinct .

B. Trichomes involved in mucilage more or
less abundant.

a Trichomes flexuous, aggregated ; joints
short and close together; sheaths uc-
coloured, very refractive

/3 Trichomes loosely interwoven, joints
of equal diameter, rather distant.

1. Spores subglobose.

2. Spores oval.

* Mucilage soft ; sheath none,

indistinct, or uncoloured
** Mucilage firm ; sheaths and

1. hederula.

2. tenuissimum.

3. LINCKIA.

4. PISCINALE.

5. CARNEUM.

mucilage tinged with yellow at

the periphery . . . .6. nvulare.

II. GELATINOSA. Fronds soft and gelatinous ; adherent ; joints of
tiichotnes cylindrically elongated in the young filaments. Spores
oblong, large.

A. Growing in watery or inundated places;
fronds thick, deformed.

a Trichomes heterogenous, composed of
two sorts of joints, one cylindrical, the
other cask-shaped or compressed spheri-
cal .....••

)8 Trichomes homogenous

B. Plant terrestrial. Frond plane, applied to
the ground by the inferior surface

7. SPONGIJEFORME.

8. yelatinosum.

9. ELLIPSOSPORUM.

III. HUMIFUSA. Terrestrial species. Fronds at first globose, then con-
fluent, and forming gelatinous cushions adhering to the substratum by
their lower face. Spores smooth.

A. Fronds in orbicular discs, or indefinite and
continuous.

226 NEMATOGEN.E.

a Spores measuring '004 x '008 mm. or more.

1. Sheaths confluent, trichomes scat-
tered, irregularly interlaced.

* Spores rounded oval . . 10. collinum.
** Spores oval . . . .11. MUSCOBUM.

2. Sheaths well defined, and separable
by pressure, trichomes folded ver-
tically and parallel . . .12. Passerinianum.

&. Spores measuring *004 x -006 mm. or more.

* Mucilage tolerably firm ; tri-
chomes olive. Spores oval . 13. HUMIFTJSUM.

** Mucilage soft, easily diffluent,
trichomes seruginous green.
Spores subglobose . . .14. calcicola.
B. Fronds deformed, hollow ; joints spherical
compressed 15. foliaceum.

IV. COMMUNIA. Terrestrial species (sometimes inundated). Fronds at
first globose, then becoming tongue-shaped, plane, or irregular, not
adherent.

Adult frond suborbicular, folded, undulate,
entire or lobed, often perforated ; joints
spherical-compressed, uniform . . .16. COMMUNE.

V. SPHJERICA. Fronds globose or subglobose (often becoming irregular
when they grow large), limited by a firm and resisting periderrnic
coating.

A. Terrestrial species, or sometimes inundated.

a Trichomes not fusiforrnly swollen be-
tween the heterocysts.

1. Fronds attaining 1 m. and more.
Trichomes torulose.

* Frond firm, trichomes com-
pact, joints cask-shaped, or
compressed sphasrical close to-
gether, uniform ; spores oval,

smooth 17. SPHJERICUM.

** Fronds soft, trichomes much
spaced out, of unequal size,
joints nearly spherical, sheaths
often coloured, contrasting
with the generally uncoloured
mucilage ; spores oval, smooth 18. RUPESTRE.
2 Fronds very small, punctiform, not
attaining 1 mm.

Trichomes large ; joints cylin-
drical, a little constricted at the
point of junction ; spores glo-
bose, smooth . . . .19. MACROSPORUM.
/3 Trichomes fusiforrnly swollen between
the heterocysts ; joints dissimilar, the
one kind straight and elongated, the
other larger and spherical ; spores
sphaerical, rough 20. spTiceroides .

B. Aquatic species (colour blue, or approach-
ing to blue).

a Trichomes dissimilar, unequal ; joints
of two forms, the one (young) elon-
gated, the other large, spherical, often
filled with opaque granules . . .21. CCERULEUM.

NOSTOCE^E. 227

ft Trichoines homogenous, regular.

1. Frond very small ; trichomes very

compact 22. minutissimum.

2. Frond attaining 2-10 mm.

* Joints spherical, compressed . 23. gregarium.
** Joints discoid, very compact . 24. edule.

3. Fronds attaining the size of a nut 25. PRUNIFORME.

VI. VERRUCOSA. Aquatic species. Fronds rounded or discoid, at first
full, then hollow, limited at the circumference by a firm and tough
periderm. Trichomes thin, very regular, spaced out and a little
flexuous at the centre, more compact, and very distorted at the peri-
phery.

a. Fronds subglobose or warted. Mucilage
tolerably soft. Trichomes medium com-
pact, and often deprived of sheaths at

the periphery 26. VERRUCOSUM.

b. Fronds at first discoid or tongue-shaped,
a little ovoid, hard ; trichomes radiating
regularly from the centre to the circum-
ference and there forming a very dense

layer 27. parmelioides.

VII. ZETTERSTEDTIANA. Aquatic species. Fronds sphserical, hard,
tuberculose, divided into radiating separable

lobes 28. Zetterstedtii.

VIII. FLAGELLIFORMIA. Terrestrial species. Fronds forming thongs,
linear straight, and very long.

Frond linear or setaceous, subdichotomous
trichomes longitudinally parallel . . 29. flagelliforme.

I. INTRICATA. Species aquatic, fronds soft, gelatinous without
determinate form, often floating.

Nostoc Linckia. (Roth.) Born % Thur. Notes Alg. p. 86, t. 28,

/. 1-12.

Fronds lobed, multipartite, free swimming, as large as n
walnut, lobes elongated and anastomosing, seruginous green, at
length becoming brownish.

Trichomes flexuous, aggregated, joints short and close,
spherical, or sphaeiical compressed, sheaths uncoloured, very
refractive. Heterocysts slightly oblong. Spores subglobose or
oval.

SIZE. Joints -0035 mm., heterocysts '005- '006 mm. diam.,
spores (in form intricatwii) subglobose -0065 X *OU9 mm.

Rivularia Linkia, Roth. Neue Beitr. p. 263.

Nostoc confusum, Ag. Syst. Alg. p. 22.

Monormia intricata, Berk. Glean, t. 18. Hass. Alg. 286, t.
75, f. 11. Ralfs. Ann. Nat. Hist. 1850, p. 326, t. 8, f. 1.

Anabaena intricata, Kutz. Phyc. Germ. 171. Rabh. Alg,
Eur. ii., 183.

Anabaena flos-aquce, Rabh. Alg. Sachs. No. 27.

228 NEMATOGENJS.

Nostoc piscinale > "Wittr. & Nord. Alg. Exs. No. 195.
Nostoc intricatum, Meneg. Nost. Ital. p. 122. Borzi Alghe
Fico. p. 283.

In ditches (slightly brackish).

" Forming small roundish gelatinous masses, floating amongst different
species of Lemna in fresh water, but probably within the influence of the
tide, and also amongst Enteromorpha intestinalis, and even within the
frond in brackish water. The plant is at first of an olive yellow gradually
assuming a greener tint, and when dried of a deep verdigris. Very
gelatinous, delicately branched, the branches very flaccid. Under a high
magnifier the whole plant is evidently composed of gelatine, in the centre of
which runs a single moniliform filament, following the ramifications, and
in its progress curling to and fro repeatedly across the thread, the joints
bein_' nearly globular. The specimens from the interior of Enteromorplta
are paler, and have longer joints amongst the globular ones." —

Plate LXXXIX. Jig. 1. Nostoc Linkia (intricata) nat. size, after
Berkeley.

Fig. 2. Nostoc completely developed, composed of the interlacings of
a single trichome X 350.

Fig. 3. Portion of trichome, spores arrived at complete maturity X 650.

Fig. 4. a, spore commencing to germinate ; b, c, d, e, spores in
germination more or less advanced X 650.

Fig. 5. Germinating filament changed into a hormogone X 650.

Fig. 6. Free hormogone X 650.

Fig. 7. Motile trichornes segmenting in fragments, of which each
constitutes a hormogone.

Fig. 8. Immovable hormogone commencing to develope X 640.

Fig. 9. Development of hormogones X 650.

Fig. 10. Group of spores germinating X 350.

Fig. 11. Chaplets of spores obtained by cultivation in germination X
650. Figs 2 to 11. After Bornet.

Nostoc piscinale. Kutz. Tab. Phyc. IL, t. 11, /. 3.

Fronds attached or free swimming, bullate and tuberculate,
verdigris green, rarely rnfescent, becoming olivaceous by age.

Trichomes loosely interwoven, joints equal in diameter, rather
distant. Spores subglobose.

SIZE. — Joints •0037-'004 mm., heterocysts '006 mm., spores
•007 x -008mm.

Born. & Thuret Notes Alg. ii., 90.

Nostoc lacustre, Kutz. Tab. Phyc. ii., t. 11, f. 2. Eabh. Alg.
Eur. ii., 179. Borzi Alghe Fico. p. 281.

Nostoc agglutinans, Kutz. Tab. Phyc. ii., t. 10, f. 1. Rabh.
Alg. Eur. ii., 178.

In ditches.

Plate LXXXIX. jig. 12. Trichomes of N. piscinale X 400 ; fig. 13,
portion of trichome with heterocyst x 600 ; fig. 14, spores in course of
development, with mature spores X 600; fig. 15, spores in the early
stages of germination. X 600.

NOSTOCE-E. 229

carneum. Aq. Syst. Alg. p. 22.

Frond indefinitely expanded, bullate and undulate, flesh
coloured, rufescent or purplish.

Trichomes loosely interwoven, joints equal, sheath none, in-
distinct, or uacoloured, spores oval.

SIZE. Joints -OOoT-'OOl mm., heterocysts '006 mm. diam.,
spores -006 X '009 mm.

Rabh. Alg. Ear. ii., p. 180. Born, and Tliuret, Notes Alg. p.

91.

Nostoc variegalum, Harv. Man. 183. Kutz. Sp. Alg. 301.
Hass. Alg. p. 287, t. 74, f. 3.

Nostoc purpurascens, Kutz. Tab. Phyc. ii., t. 11, f. 4.
Nostoc rufescens, Ag. Syst. 22. Rabh. Alg. Eur. ii., 179.

On rocks.

"First collected in Ireland in 1836, growing on the face of a moist
bank over which water trickled. When recent it formed a soft gelatinous
mass, of a livid colour, bearing the closest resemblance, both in substance
and colour, to those gelatinous medusee which are cast ashore along the
coast."-— Moore.

Plate XC. Jig. 1. Nostoc cavneum, natural size ; fig. 2, trichomes
X 400 ; fig. 3, development of spores X 600.

II. GELATINOSA. Fronds soft and gelatinous, adherent, joints of
trichome cylindrical^ elongated in the young filaments. Spores

oblong, large.

Nostoc spongiaeforme. Ag. Syst. Alg. pt 22.

Frond at first subglobose, then indefinitely expanded, be-
coming rather firm, pale seruginous or olive green, surface
tuberculated.

Trichomes heterogenous, composed of two sorts of joints, one
cylindrical the other cask-shaped, or compressed sphserical.
Heterocysts globose. Spores smooth, oblong.

SIZE. Joints '004 mm., heterocysts •G07-'OOS mm., spores
•006--007 x -01--012 mm.

Born. & Thuret Notes Alg. p. 92. Rabh. Alg. Eur. ii. 178.
Kutz. Tab. Pbyc. ii., t. 9, f. 4.

Nostoc inundatum, Kutz. Spec. Alg. 299. Rabh. Alg. Eur.

ii., 171.

Hormosiphon inundatum, Kutz. Tab. Phyc. ii., t. 27, f. 2.
Hormosiphon stagnalis, Kutz. Tab. Phyc. ii., t. 27, f. 3.
Hormosiphon natans, Kutz. Tab. Phyc. ii., t. 27, f. 4.

In wet or inundated places.

Plate XC. fg. 4. Nostoc spongioeforme, natural size ; fig. 5, young
trichome ; fig. 6, mature trichome X 4UO ; fig. 7, portion of mature
trichome X 600.

230 NEMATOGEN^E.

Nostoc ellipsosporum. (Desm.) Rabh. Alg. Eur. n., 169.

Plant terrestrial. Frond plane, applied to the ground by the
lower surface, gelatinous, rufous brown.

Tricbomes densely interwoven, pale a?ruginous green, joints
cylindrically elongated, loosely connected, slieatbs broad, homo-
genous. Heterocysts elongated, elliptical, spores oblong,
smooth.

SIZE. Joints '004 mm., heterocysts -006--007 mm., spores
•006 x -006--008 x -019 mm.

Born. & Thuret Notes Alg. ii., 94, t. xxvii., fig. 7-11.

Hormosiphon ellipsosporum^ Desm. PL Crypt. No. 133.

On the ground amongst moss.

Plate XC. Jig. 8. Trichome of Nostoc ellipsosporum producing spores
X 400 ; fig. 9, portion of trichome which at one extremity exhibits the
sheath ; fig. 10, trichome with the greater part of the joints transformed
into spores ; fig. 11, young trichome from germinating spore. Figs. 9,
10, 11, X 600 diam. after Bornet.

III. HUMIFUSA. Species terrestrial. Fronds at first globose,
then confluent, and forming gelatinous patches adhering by their

lower face. Spores smooth.

Nostoc muscorum. Ag. Disp. Alg. p. 55.

Frond dark green, foliaceous, tuberculate, opaque.

Trichomes diffused, irregularly interwoven, pale geruginous
green. Sheaths confluent. Heterocysts spherical, usually
intercalated. Spores oval.

SIZE. Joints -0035 mm., heterocysts -005 mm., spores -006
x -01 mm.

Born. & Thuret Notes Alg. p. 96, t. 27. Rabh. Alg. Eur. ii.,
173. Eng. Fl. v., 399. Hass. Alg. 292, t. 74, f. 4. Gray
Arr. i., 351.

On calcareous rocks, and the mosses that cover them.

Plate XC. fig. 12. Nostoc muscorum nat. size ; fig. 13, trichome X
400; fig. 14, sterile trichome; fig, 15, fructifying trichome; fig. 17,
trichome with spores involved in sheath ; figs. 17, 18, spores germinating ;
figs. 14-18, X GOO, after Bornet.

Nostoc humifusum. Carm. Eng. Fl. n., 399,

Frond small, at first globose or subglobose, from the size of
a peppercorn, olive, then brownish, shining opaque when dry.

Trichomes olive, slender, vertically folded, sheaths well de-
fined. Heterocysts globose. Spores oval.

SIZE. Joints -0022 mm., heterocysts '003 mm., spores '004
x-006 mm.

NOSTOCE.E. 231

Harv. Man. p. 184. Born. & Thuret Notes Alg. p. 99.

Nostoc parietinum, Rabh. Alg. Ear. ii., 178.

Anabaena granularis, Kutz. Tab. Phyc. i., t. 94, f. 6.

Nostoc granulare, Rabh. Alg. Ear. ii., 163.

Nostoc tepidariorum, Braun. in Rabh. Alg. No. 2461, 2462.

On mosses and on walls in greenhouses, &c.

Plate XC I. fig. I. Nostoc humlfiisnm, nat. size; fig. 2, trichome x
400 ; fig. 3, portion of trichome x GOO.

IV. COMMUNIA. Species terrestrial. Fronds at first globose,

then tongue-shaped^ plane or irregular.

Nostoc commune. Vaucli. Con/, p. 222, t. 16,/. 1.

Adult frond sub-orbicular, folded, undulating, entire or lobed,
often perforated, olive, yellowish-brown, or becoming brownish.

Trichomes flexuous, loosely interwoven, pale blue-green.
Joints spherical, compressed, uniform. Heterocysts globose.

SIZE. Joints, '0045-'006 (usually -005) mm., heterocysts
•007 mm.

Rabh. Alg. Eur. ii., 175. Hass. Alg. t. 74, f. 2. Borzi.
Alghe Fico. p. 284. Eng. Bot, i., t. 2556, pi. p. 1625. Eng.
Bot. i., t. 461. Relh. Cant. 441. Lightf. Fl. Scot. 898. Purt.
Midi. Fl. ii., 612. Abbot. Bedf. 271. With. AIT. iv., 80.
.Tenner Fl. Tunb. Wells, 190. Harv. Man. 183. Johnst.
Fl. Berw. ii., 262. Grev. Fl. Edin. 322. Mack. Hib. 245.
Flor. Dev. ii., 49. Eng. Fl. v., 398. Dickie Bot. Guide, 310.

Tremella nostoc, Linn. sp.

Nostoc cinifionum, Born. & Thuret Notes Alg. ii., 102.

Nostoc foliaceum, Ag, Syst. Alg. p. 19. Hass. Alg. t. 76,
f. 2. Rabh. Alg. Eur. ii., 173. Eng. Fl. v., 399. Harv. Man.
183. Mac. Hib. 245. Dickie Bot. Guide, 310.

Nostoc arctum, Kutz. Tab. Phyc. ii., t. 7, f. 1.

No-stoc littorale, Kutz. Tab. Phyc. ii , t. 8, f. 1.

Nostoc prismaticum, Ces. in Rabh. Alg. Eur. ii., 169.

Nostoc riigosum, Kutz. Tab. Phyc. ii., t. 11, f. 1.

Nostoc salswn, Kutz. Tab. Phyc. ii., t. 8, f. 3.

On wet ground.

Plate XCL fig. 4. Nostoc commune, nat. size ; fig. 5 trichome x400 ;
fig. 6, portions of trichome x 600, fig. 7, portion of trichome.

V. SPH.ERICA. Fronds globose or subglobose (becoming irregular
when they grow large), limited by a firm and resisting peridermic

coating.

Nostoc sphaericum. Vaucli. Conf. 223, t. 16, /. 2.

Fronds firm, sphserieal, about the size of a pea, gregarious,
olive or bluish-green, or brownish, with a firm brownish or
colourless periderm.

2 K

232 NEMATOGEN.E.

Trichomes compact, densely interwoven at the periphery,
joints cask-shaped, or compressed sphserical, close together,
uniform. Heterocysts subglobose. Spores oval, with a thick
tegument, smooth.

SIZE. Joints -004--005 mm., heterocysts -006 mm., spores
•005 x -007 mm.

Born. & Thuret Notes Alg. p. 108. Eabh. Alg. Eur. No.
746. Harv. Man. 184. Gray Arr. i., 352. Eng. Fl. v., 400.
Hass. Alg. 289, t. 76, f. 5 (?). Dickie Bot. Guide, 330.

Nostoc vesicarium, Menegh. Nost. Ital. p. 108 (not Harvey).

Ulva pisiformis, Huds. Fl. Ang. ii., 572.

In springs and mountain rivulets.

" Fronds from half a line to two lines in diameter, globular, firm,
smooth, solid, heaped on each other like a parcel of small shells. In-
ternal filaments rather thinly scattered through the mass." — Carmichael.

Plate XCI. Jig. 8. Nostoc spkcericum nat. size ; fig. 9, trichome x 400 ;
fig. 10, portion of trichome x 600 ; fig. 11, spores x 600.

Nostoc mpestre. Kutz. Spec. Alg. p. 296.

Fronds soft, globose, olive, becoming brownish, often forming
an irregular crust.

Trichomes much spaced out, of unequal size, joints nearly
sphaerical, sheaths often coloured, contrasting with the generally
uncoloured jelly. Spores oval with a smooth tegument.

SIZE. Joints '005- '008 mm., heterocysts '007 mm.

Rabh. Alg. Eur. ii., 163. Thuret Notes Alg. p. 112. Borzi
Alghe Fico. p. 283.

Nostoc microscopicum, Carm. Harv. Eng. Fl. ii., 399. Harv.
Man. 184. Mack. Hib. 245.

On rocks, overrunning mosses. &c.

This species is mixed up by Hassall with Nostoc mitscorum, if it be not
in reality the whole of that species, for there is some doubt whether N.
muscorum, as defined by Bornet and Thnret was known to him.

Plate XCI. Jig. 12. Involved trichomes of N* rupestre x 400 ; figs. 13,
14, 15, young plants in course of development x 400, after Borzi.

Nostoc macrosporum. Meneg. Mon.Nost. 116, t. 14, f. 2.

Fronds very small, punctiform, geruginous-green, or brownish-
olive.

Trichomes large, bluish-green, or brownish, joints cylindrical,
a little constricted at their junction. Sheaths broad, brownish
or yellowish-brown. Heterocysts globose. Spores globose with
a smooth tegument.

SIZE. Joints '008-'009 mm., heterocysts '009-*01 mm.

Born & Thuret Notes Alg. p. 112. Rabh. Alg. Eur. ii., 163.
Hass. Alg. 293, t. 73, f. 1, 2. Borzi Alghe Fico. p. 283.

NOSTOCEJ3 233

B ormosiphon macrosporus, Kutz. Tab. Phyc. ii., t. 13, f. 1.
Diplocolon Heppiij Itzig. Phyc. Stud. t. 11, f. 8-12.
Nostoc pyreniacum, Ripart. Bull. Soc. Bot. Fr. (1868.)
Nostoc ichthyon, Rabh. Alg. Eur. ii., 164.

On rocks among moss.

Plate XC 1 1. Jigs. 1, 2. Involved trichomes of N. macrosporum x 400 ;
fig. 3, development of hormogone, x 400, after Borzi.

Nostoc caeruleum. Lyngb. Hydr. Dan. t. 68, /. B.

Fronds, small, globose or subglobose Q to 4 lines) , fixed or
free swimming, usually gregarious, blue or greenish-blue.

Trichomes dissimilar, unequal, joints of two forms, the one
(young) elongated, the other larger, nearly sphssrical, some-
times filled with opaque granules.

SIZE. Joints '004--007 mm., heterocysts -008 mm.

Born. & Thuret Notes Alg. p. 114. Rabh. Alg. Eur. ii., 167.
Nord. & Wittr. Alg. Exs. No. 98. Grey. Sc. Crypt. Fl. 1. 131.
Hass. Alg. 293, t. 76, f. 11, t. 75, f. 10, t. 74, f. 1. Eng. Fl.
v., 400. Harv. Man. 183. Gray Arr. i., 352.

Nostoc ccerulescens, Rabh. Alg. Eur. ii., 168.

Nostoc ftzigsohnii, Rabh. Alg. Eur. ii., 168.

On mosses and submerged plants.

Plate XCII. fig. 4. Plants of Nostoc cceruleum natural size ; fig. 5.
trichomes x 400 j fig. 6, portion of trichome x 600.

Nostoc piunif orme . Ag. Disp. Alg. p. 45.

Frond from the size of a pea to that of a damson, or larger,
olive or dark eeruginous-green, when old becoming blackish-
brown, with a coriaceous periderm, and watery within.

Trichomes loosely interwoven, joints subglobose, compressed,
closely connected. Heterocysts globose, usually terminal.

SIZE. Joints '004-'005 mm., heterocysts <(J06-'007 mm.

Born. & Thuret Notes Alg. p. 116. Rabh. Alg. Eur. ii.
Kutz. Tab. Phy. ii., t. 4, f. 4. Witt. & Nord. Alg. Exs. 97,
276. (?) Berk. Glean, t. 19, f. 2. Hass. Alg. 291, t. 76, f.
3,4. Eng. Fl. v., 399. Harv. Man. 183. Gray Arr. i., 352.

Ulva pruniformis, Hiuls. Aug. ii., 572. Abbot. Bedf. 274.
With. Arr. iv., 120. Hull. Br. Fl. 310.

Nostoc coccymelon, Kutz. Tab. Phyc. ii., t. 4, f. 3.

In freshwater pools, rivulets, &c.

Plate XCII. fig. 7. Nostoc pruniforme, natural size ; fig. 8. trichome
x 400 ; fig. 9, portion of trichome, with spores in course of formation
x600.

234 NEMATOGEN.E.

VI. VERRUCOSA. Species aquatic. Fronds rounded or discoid r
filled, then hollow, witli a tough periderm.

Nostoc veirmcosum. VancJi. Conf. 225, t. xvi., /. 3.

Fronds subglobose or nodulose, warted, brownish-green, jelly
tolerably soft, limited at the circumference by a firm, and tough
periderm.

Trichomes slender, somewliat compact, spaced out, and a,
little flexuous at the centre, more compact and distorted at the
periphery, where they are often deprived of sheaths. Joints
subglobose, closely connected. Heterocysts spherical.

SIZE. Joints '003-'0035 mm., heterocysts -006 mm., spores
•005--007 mm.

Born. & Thuret Notes Alg. p. 117. Thur. Ann. Sci. Nat.
1844, ii., t. 9, f. 1-5. Eabh. Alg. Eur. ii., 176. Borzi Alghe
Fico. p. 284. Hass. Alg. 291, t. 76, f. 1. Grev. Fl. Ed. 323.
Hook. FL Scot, ii., 74. Mack. Hib. 245. Fl. Dev. ii., 49.
Gray AIT. i., 351. Kutz. Tab. Phyc. ii., t. 9, f. 11. Eng. FL
v., 400. Harv. Man. 183. Dickie Bot. Guide, 310.

Nostoc irregulare, Wartm. in Rabh. Alg. Eur. ii., 167.

Nostoc nival e, Kutz. Tab. Phyc. ii., t. 8, f. 4.

Nostoc Peloponnesiacum, Kutz. Tab. Phyc. ii., t. 9, f. 3.

Nostoc splicericum, Meneg. Nost. Ital. 110. Kutz. Tab. Phyc.
ii., t. 3, f. 2.

Tremella verrucosa, Huds. Fl. Aug. Lightf. Fl. Scot. 898,
With. AIT. iv., 81.

In streams, attached to stones.

Plate XCII. fig. 10. Nostoc verrucosiim, natural size ; fig. 11. tri-
chomes x 400 ; figs. 12-13, portions of trichome ; fig. 14, horrnogones
undergoing division ; figs. 12 to 14 x 600, after Thuret ; fig. 16, spores;
fig. 17, spore in germination x 600.

GEN PS 95. ANABAENA. Bory. (1823.)

Trichomes moniliform, without sheaths (or rarely vaginate),
composed of sub-globose cells, some of which become changed
into globose or elongated spores, usually yellowish brown or
golden brown. Heterocysts intercalated in the trichomes.
Spores originating in cells not adjoining the heterocysts. —
Born, and Thur. Notes Alg.

Eecent authors have modified this genus in different directions. Borzi
does not adopt the same limitations as Thuret, neither does Kirchuer or
Professors Nordstedt and Wittrock.

235

Professor Wittrook suggests that the genus Anabaena should be
divided into four sab-genera, under the following designations : —

SUB-GEN. 1. Trichormus. Spores globose, or subglobose, hetero-
cysts intercalated, distant from the spores.

SUB-GEN. 2. Dolichospermum. Spores subellipsoid or sub-
cylindrical, heterocysts as in Trichormus.

SUB-GEN. 3. Sphaerozyga. Spores subellipsoid or subcylindrical,
heterocysts intercalated, proximate to the spores.

SUB-GEN. 4. Cylindrospermum. Spores subellipsoid or cylindrical,
heterocysts for the most part terminal and proximate to the spores.

Anabaena flos-aquae. Kutz. Tab. Phyc. i., t. 94.

Free swimming, membranaceous, blue-green. Trichomes more
or less curved, often circinate, joints sphserical, or from mutual
pressure elliptic or quadrate. Heterocysts intercalated, elliptical.
Spores globose.

SIZE. Cells -0045--006 nmi ; heterocysts -012--014 mm.
long ; spores 'OOS-'Ol mm.

Rabh. Alg. Eur. ii., 182. Kirch. Alg. Schl. 235.

Nostoc ftos aquce, Lyngb. Hydro, t. 68, f. D.

Trichormus incurvus, Allm. Ann. Nat. Hist, xi., 163.

var. circinalis. Kirch. Alg. Sclil. 235.

Trichomes more circinate, and joints rather larger.
SIZE. Cells -007--01 mm. ; spores -012- -014 mm. diam.
Anabaena circinalis, Rabh. Alg. Eur. ii., 183.
Anabaena spiralis, Thompson Ann. Nat. Hist. (1846) v.,
p. 81.

Trichormus spiralis, Ralfs Ann Nat. Hist. (1850) p. 328.

In ponds, moor pools, &c.

Plate XCIII. Jig. 1. Trichomes X 40Q diam.; b Trichormus spiralis
after Ralfs ; c var. circinalis, trichomes x 400.

From the description and figure given by Ealfs, under the name of
Trichormus spiralis, we have no donbt that Thompson's Alga, which
himself termed Anabaena spiralis, was the variety circinalis of this
species, although Hassall's figure and interpretation is entirely different.
The account which Thompson gives of his " Alga which colours Bally-
drain Lake," is as follows : —

" On visiting the lake (July 15) to-day I found that the whole body of
water was tinged with a dull faintly glaucous hue. On going out in a
boat to ascertain the cause of this appearance, I saw that the wrater was
everywhere filled with extremely minute particles, which might be com-
pared to the motes in a sunbeam. To the unassisted eye they seemed
as delicate as the finest human hair, and of a spiral form. On enquiry
I learned that the appearance had been observed only for the last four
or five years, and for about three months in each year. One of my
friends had looked upon its approach with dread, as it interfered so
much with his angling, that during the period of its continuance this
spot had to be abandoned." Subsequently the plant was observed as

2 L

236 NEMATOGEN.E.

late as the 27th September, but on October 7th all had disappeared. In
the following year the Alga was seen first on the 3rd of July, and last
on the 23rd of September.

" The specimens obtained were invariably of similar breadth, and
rarely presented more than four spiral turns, and when of this size were
l-50thof an inch in length. The species at first, when mingling with
the water, is of a dark green colour, when in calm weather it ascends to
the surface in separate particles it appears pale green ; when it does so
en masse (the earliest symptoms of decay) it is of a pale blue, and in the
last stage of decomposition ferruginous. When two of the spiral
portions come in contact they have an elastic power, by which they can,
though slowly, disentangle themselves, and separate from each other."

Anabaena vaxiabilis. Kutz. Phyc. Gen,

Gelatinous, submembranaceous, deep blue-green. Trichomes
slightly flexuously curved, almost parallel, verdigris green, joints
globose or elliptic, compressed or depressedly subcylindrical,
I-ITT times longer tban broad ; heterocysts intercalated, paler ;
spores numerous, seriate, ellipsoid, golden tawny, with a rather
thick membrane.

SIZE. Cells -0035--004 mm. ; heterocysts '007 mm. ; spores
•00801 x -012mm.

Sphcerozyga Thwaitesii, Harv. Phyc. Britt. t. 113, B,

Sphaerozyga variabilis, Kutz. Tab. Phyc. i., t. 96, Rabh. Alg.
Eur. ii., 193.

Tricliormus rectus, Ralfs Ann. Nat. Hist. (1850) t. 8, f. 6.

Anabaena licheniformis, Hass. Alg. 82, t. 75, f . 4 ?

Trichormus Thwaitesii, Ralfs Ann. Nat. Hist. (1850) p.
329, t. 8, f. 4.

In ditches.

It forms thin gelatinous dark green patches either on the damp soil
covered at springtides, or at the bottom of brackish ditches and pools.

Plate XCI2I. fig. 2. Trichomes X 400, with heterocysts and spores.
Anabaena Hassallii. Nord. and Wittr. Algce Exs.

Trichomes equal, curved, often circinate, interwoven in a thin
blue-green stratum, joints globose or more or less compressed,
delicately granular ; heterocysts sphaerical, colourless, interca-
lated without order ; spores oblong cylindrical, single or in pairs,
distinctly curved, dark blue green, densely granulated, l^-2^
times as long as broad.

SIZE. Cells '008 mm. ; heterocysts •009-'01 mm. ; spores
•012 x 025 mm.

Sphcerozyga Hassallii, Rabh. Alg. Eur. ii., 195.

Anabaena flos-aquce, Hass. Alg. 282, t. 75, f. 2, Harv. Man.
p. 186.

Dolichospermum Thompsoni, Ann. Nat. Hist. (1850), t. 9,
f. 3.

NOSTOCEJS. 237

Anabaena circinalis, Phillips in Grevillca ix., p. 4, t. 134,
figs, e, /, g.

In ditches with Confervce, and floating on lakes.

" Floating like powdered verdigris on mountain lochs." This species
seems to be variable in the form and size of the spores, and in the number
of vegetative cells which occur between the heterocysts and spores.
Wittrock has figured varieties in which two, or even sometimes one,
cell intervenes between the heterocyst and spore, alluding to the fact
that in English specimens they are sometimes in juxtaposition. Al-
though technically the Shropshire specimens would seem to belong to
Sphcerozyga, yet in all other features they agree so well with this species
that we have cited them here as abnormal forms of the present species.

Plate XC 111. Jig. 3. Portions of trichomes with heterocysts and
spores X 400 ; b, after Kalfs ; c, after Phillips.

Anabaena Ralfsii. (Ruiz.)

Forming extensive strata of a velvety rich dark green colour,
sometimes verging towards verdigris green.

Trichomes moniliform, joints sphserical. Heterocysts ellip-
tical, spores elliptic or cylindrical, one or two in each series
not contiguous to the heterocysts.

SIZE. Cells -004 mm. diam. Heterocysts -005--006 x 008
mm. Spores -008--01 x -022--03 mm.

SpTicsrozyga Ralfsii (Thw.) Eabh. Alg. Eur. ii., 193. Kirch.
Alg. Schl. 237.

Doliclwspermum Raljsii, Ann. Nat. His. 1850, t. 9, f. 2.

Cylindrospermwn Ralfsii, Kutz. Tab. Phyc. t. 98, f. 7.

In bogs and rivulets.

" Distinguished from A. intequalis by its elliptical heterocysts (which
are comparatively less broad), by its more orbicular ordinary joints, and
by having fewer spores." — Ralfs.

Plate XCIV. 'fig. 1. Trichomes with heterocysts and spores X 400
diam.

Anabaena Smithii. (7 Ait;.) Nord. $ Wittr. Alg. Exs. No. 197.

Trichomes straight, each included in a definite gelatinous
sheath ; joints sTibsphserical, compressed, about as long as wide ;
heteroeysts subsphserical somewhat barrel shaped, half as wide
again as the joints, puncta very distinct ; spores cylindrical, very
unequal in length, with the ends rounded and somewhat trun-
cate.

SIZE. Cells -004--006 mm. diam. Heterocysts -008--009 x
•009--013 mm. Spores -009--012 x -02--04 mm. (Wittrock.)

Dolichospermum /Smithii, Thwaites Ann. Nat. Hi*t. IboO, t. 9,
f. 4.

In boggy pools with other Alga?.

238 NEMATOGEtt^E.

" Immediately distinguishable from its congeners on account of its
possessing a definite gelatinous sheath to each of its filaments, which
are of smaller diameter than those of any other species of Dolicliosper-
mum. The ordinary cells are subspherical, somewhat compressed, and
of less diameter than the heterocysts, which are barrel-shaped, and
with very distinct puncta. The numerous spores, which are about twice
the diameter of the ordinary cells, are elongated and cylindrical, very
variable in length and in the number which occur together, and their
ends are slightly truncate." — Rolfs.

Plate XCIII. fig. 7. Portions of trichomes with heterocysts and
spores X 400 ; fig. a from Scandinavian specimens ; fig. b from British
specimens.

Anabaena oscillarioides. Bory. Diet. Hist. Nat.

Forming a bluish green stratum.

Trichomes elongated flexuous, joints subquadrate, distinct ;
heterocysts barrel-shaped or elliptic. Spores oval, catenate,
somewhat larger than the vegetative cells.

SIZE. Cells -G04--005 x -004--006 mm. Heterocysts -006-
•008 x -007--009 mm. Spores -007--008 X '008--012 mm.
(Wittrock.)

Nord. & Wittr. Alg. Ex. No. 196.

Sphcerozyga oscillarioides } Kutz. Sp. Alg., p. 291. Borzi.
Alg. Fico. 286.

Trichormus oscillarioides, Kalfs in Ann. Nat. Hist. 1850, p.
329, t. 8, f. 5.

In brackish ditches.

" It differs from A. TTiivaitesii by its more quadrate ordinary cells, and
by its smooth and elliptical heterocysts." — Ralfs.

Plate XCIII. fig. 6. Portions of trichomes with spores and hetero-
cysts X 400.

Anabaena Thwaitesii. (Ralfs.)

Trichomes moniliform, straight or nearly so, joints quadrate.
Heterocysts oblong sub-quadrate, hardly exceeding the joints
in diameter. Spores numerous, cylindrical with truncate ends,
very variable in length.

SIZE. Cells -006--007 mm. Heterocysts -008 x '01 mm.
Spores -01--012 X '025--03 mm.

Dolichospenniim Thwaitesii^ Ralfs Ann. Nat. Hist. 1850,
337, t. 9, f. 5.

In freshwater pools, and brackish ditches.

Allied to A. Smitliii, but its filaments are not included in a definite
gelatinous sheath. Its filaments are also stouter, and there is a differ-
ence in the form of its cells. The heterocysts are quadrangular, and
hardly exceed in diameter the ordinary cells. The cylindrical truncated
spores are numerous, many in a chain, and variable in length, about
twice the diameter of ordinary cells.

Plate XC11I. fig. 5. Portions of trichomes with heterocysts and
spores X 400.

NOSTOCE^E. 239

Uncertain Species.
Anabaena inaequalis. (Ealfs.) Braun., in litt.

Forming extensive strata consisting of thick gelatinous masses
of a deep green colour.

Trichomes stout, moniliform, elongated, joints distinct, at first
quadrate, finally orbicular, with granular contents. Heterocysts
globose, broader than the ordinary joints, occurring at short
intervals. Spores 3-4 times longer than broad, with truncate
ends, in chains of two to five.

SIZE. Not determined.

Dolicliospermum incequale, Ralfs Ann. Nat. Hist. 1850, 335,
t. 9, fig. 1.

Sphcerozyga incequalis, Kutz. Tab. Phyc. i., t. 96. Rabh.
Alg. Eur. ii., 194?

In boggy pools.

We have seen no specimens of this, or of Kutzing's Splicsrozyga
incequalis, and therefore cannot pronounce on their identity. Mr. Ealfs
says that " this plant forms extensive strata, composed of thick
gelatinous masses of a deep green colour. Filaments elongated, con-
sisting of from 100 to 200 cells, and, being stouter than in most species
belonging to this genus, visible to the naked eye. Ordinary cells dis-
tinct, quadrate in immature specimens, but at length nearly spherical,
appearing punctate on account of the scattered granular matter which
they contain. Vesicular cells (Heterocysts) spherical broader than the
ordinary joints and occurring at short intervals. Spores 3 to 4 times
longer than broad, with truncate ends ; in chains of from two to five
members." May be known from A. Ralfsii by its spherical heterocysts
and catenate spores.

Plate XC11L fig. 4. Trichomes with heterocysts and spores X 400 ;
after Ealfs.

GENUS 96. APHANIZOMENON. Morren. (1839.)

Thallus membranaceous, free swimming, bright blue, blue
green, or becoming olive. Trichomes medium size, a little
attenuated towards the apex, agglutinated parallelly and very
densely in fascicles, joints cylindrical, very closely connected,
pale blue, nearly colourless and delicately granular. Spores
elongated, cylindrical, rounded at the ends, pale blue, or some-
what olive, exospore thin, quite smooth. Borzi Alg. Ficochrom.
p. 279.

Thuret places this genus next to Analaena, but, in the absence of
heterocysts, it seems that its proper place would be in Lyngbyte, allied to
Oscillaria. We have retained it here, in preference to altering the " key
to the genera," which is given on page 221.

240 NEMATOGENJ2.

Aphanizomenon flos-aquae. Ealfs Ann. Nat. Hist. i. 9, /. 6.

Floating, forming a pale or dark blue green stratum on the
.surface of the water. Trichornes very thin, nearly straight,
aggregated in membranaceous flakes which readily separate,
either distinctly or indistinctly articulated, very pale blue or
colourless. Joints cylindrical, about as long as broad, slightly
granular. Spores more or less elongated cylindrical, 6-12 times
as long as broad, granular.

SIZE. Cells -003-004 mm. diam. Spores -005 x -03--04
mm.

Allman, Quart. Journ. Micr. Sci. 1855, p. 21, t. 3.

Byssusflos-aquce, Linn. Spec. Plant. (1753) No. 1168.

Limnochlide flos-aquce, Kutz. Tab. Phyc. i., t. 91, f. 2, a.

Aphanizomenon incurvum, Morr. Bull. Brux., 1839, Harv.
Man. 145, Hass. Alg. 280, t. 76, f. 6.

Sphcerozyga flos-aquce, Rabh. Alg. Eur. ii., 195.

In ditches, ponds, and meres.

One of the species of Algas which contribute to the phenomena cha-
racterized as " breaking of the meres," Professor Allman thinks that he
has observed heterocysts (see Micr. Journ. p. 22), but this is not con-
firmed.

Plate XC1V. fig. 1. a, Trichomes in bundles, X 200 ; b, Trichomes,
with spores X 400.

GENUS 97. SPHJEROZYGA. (Ac/.) Ealfs. (1850.)

Trichomes involved in an amorphous, often very quickly
diffluent, mucilage, rarely vaginate, agglutinated in an inde-
finite gelatinous stratum ; joints sphserical, elliptical or oblong,
transversely compressed and often quadrangular. Heterocysts
intercalated, binary, or solitary. Spores originating in cells
placed on each side of the heterocysts.

Sphaexozyga Carmichaeli. Harv. Phyc. Britt. t. 113.

Stratum thin, of a dark or bluish green colour when recent,
but opaque and glaucous when dry. Trichomes moniliforni,
with tapering extremities ; joints distinct, somewhat quadrate.
Heterocysts spherical. Spores oblong.

SIZE. Cells -OU35--0045 mm. Heterocysts -006 mm. diam.
Spores -008--01 X -018--025 mm.

Kutz. Tab. Phyc. i.,t. 99, f. 4. Ralfs Ann. Nat. Hist. 1850,
t. 8, f. 7. Rabh. Alg. Eur. ii., 191.

Belonia tonilosa, Garni. Eng. Fl. v., 379. Harv. Man. 167.

On damp soil in salt marshes flooded at spring tides, in
brackish ditches, &c.

NOSTOCE.E. 241

" The best distinctive mark of this species is the subacute extremities,
combined with the short filament and littoral habitat. There are rarely
more than one or two groups of enlarged cells, when only one is present
it is situated near the centre of the filament. I believe that the attenuated
extremities are constant, at least in the young plant, unless the filament
has been broken." — Ralfs.

Plate XG1V. jig. 3. Portions of trichomes with heterocysts and
spores X 400.

Sphaerozyga Broomei. Thwaites in Harv. Phyc. Britt.

Stratum bluish or yellowish green. Trichomes moniliform,
joints subsphserical. Heterocysts smooth, subquadrate, rather
longer than wide. Spores numerous, elliptical, twice as long as
wide, not much exceeding in width the joints, commencing to be
formed on either side next to the heterocysts.

SIZE. Cells -004 mm. Heterocysts -005 x '006 mm.
Spores -008 x '016 mm.

Thwaites in Harv. Phyc. Britt. t. 173, fig. A. Ralfs Ann.
Nat. Hist. (1850) t. 8, fig. 10.

On dead leaves of Myriophyllum in brackish ditch.

" The gelatinous matrix is firmer than in many species of this genus.
The numerous spores in each series distinguish it from every other species
I am acquainted with." — Ralfs.

Plate XC1V. fig. 4. Portions of trichomes, with heterocysts and
spores X 400.

Species imperfectly 'known.
Sphaerozyga Berkeley ana. Thwaites in Harv. Phyc. Britt.

Young trichomes included, one or several together in a de-
fined mucous sheath. Joints spherical, compressed. Hetero-
cysts spheroidal, slightly compressed. Spores usually two on
each side of the heterocysts, large, twice the width of the joints,
oblong, half as long again as wide, becoming brown when
mature.

SIZE. Cells about P006-'007 mm. Spores about -012 x
•015 mm.

Thwaites in Harv. Phyc. Britt. t. 173, fig. B. Ralfs Ann.
Nat. Hist. 1850, 334, t. 8, fig. 11.

Amongst Cladoplwra fracta, in brackish ditch.

Mr. Ralfs says : " The turgid spores and large compressed heterocysts
characterise this species," of which we have no knowledge.

Plate XCVI. fig. 9. Portions of trichomes, with heterocysts and
spores X about 400. After Harvey.

242 NEMATOGENJS.

Sphaerozyga Jacobi. Rolfs Ann. Nat. Hist. 1850, 332, t. 8, Jig. 8.

Forming thick bluish green gelatinous masses, from which
the filaments issue in long rays.

Trichomes elongated, ends attenuated, joints quadrate, then
globose, the terminal one longer than broad, and usually conical.
Heterocysts sphserical, larger than the joints. Spores oblong
or cylindrical, one or two on each side of the heterocysts.

SIZE. Cells about -005 mm. Spores -008 x '02--025 mm.

Berkeley in Eng. Bot. ii., t. 2,826, fig. 2.

Cylindrosporium licheniforme, Kutz. Spec. 292 ?

In streams, pools, &c.

We have seen no specimen of this, and cannot say whether it is
Agardh's species or not. Although ignored by Continental botanists, it
would seem from the figure, which we have reproduced, to be a distinct
species.

Plate XCIV. Jiff. 5. Portions of trichomes with heterocysts and
spores X about 400, after Ralfs.

Sphaerozyga Mooreana. Ralfs Ann. Nat. Hist. 1850, t. 8, /. 12.

Trichomes scattered, joints minute, somewhat orbicular.
Heterocysts minute, barrel-shaped, much narrower than the
spores. Spores very turgid, often nearly orbicular or broadly
elliptical, much larger than the joints or heterocysts.

SIZE. Cells about •Q035-'004 mm. Spores about -008 x
•012--015 mm.

Mixed with other algae.

" I have only seen imperfect and dried filaments of this species inter-
mixed with Nostoc variegatum, Moore ; in a recent state therefore the
form of the joints may not agree with the above description, still the
large turgid spores must distinguish it from every species but 8.
Berkeley ana, and from that it differs in its heterocysts, which are com-
paratively much smaller and also longer than broad." — Ralfs.

Plate XCIV. fig. 6. Portion of trichome with heterocyst and spores
X about 400 after Ralfs.

Sphaerozyga leptosperma. Ralfs. Ann. Nat. Hist. 1850, 334, t. 8,

/. 13.

Forming large shapeless gelatinous masses, varying from deep
green to pale yellowish green.

Trichomes elongated, not constricted at the dissepiments,
joints longer than broad, separated only by transverse dissepi-
ments, which are not contracted, and indeed are often so obscure
that they can hardly be detected. Heterocysts at first barrel-
shaped, finally elliptic, broad at the spores. Spores cylindrical,
4-6 times longer than broad truncate, slightly broader than the
ordinary joints.

NOSTOCE.E. 243

SIZE. Cells -004 mm. diam. Spores about -007 x -02--03
mm.

Cylindrospermum leptospennum, Kutz. Tab. Phyc. i., t. 99.
f. 11. Bot. Leit. p. 198.

In ditclies and pools.

" The confluent vegetative cells, with their obscure dissepiments, dis-
tinguish this from every other British species." — Rolfs.
Of this also we have no personal knowledge.

Plate J.QIV. fig. 8. Portion of trichome with heterocyst and spores
X about 400. After Ralfs.

Sphaerozyga elastica. Ralfs Ann. Nat. Hist. 1850, 333, t. 8, fig. 9.

Stratum deep bluish green, tender.

Trichomes elongated, constricted at the dissepiments, joints
about equal in length and breadth, but when dividing they
lengthen, and though quadrate in the recent plant they acquire
slightly rounded angles when dry. Heterocysts at first barrel-
shaped, then elliptic. Spores cylindrical, 4-8 times longer
than broad, ends at first truncate, but rounded after separation.

SIZE. Cells about -005 mm. Spores -008 x '025 mm.

Sphcerozyga elastica, Agardh Icon. Alg. ?

Cylindrospermum elongatum, Kutz. Tab. Phyc. i., t. 99, f.
111.

In bogs.

" The moniliform filaments and shorter joints distinguish this species
from S. leptosperma, and its elliptic heterocysts from S. Jacobi and S.
Carmichaeli." — Ralfs .

Plate XCIV. fig. 7. Portions of trichomes with heterocysts and
spores X about 400, after Ralfs.

GENUS 98. CYLINDROSPERMUM:. (Kutz.) Ralfs 1850.

Heterocysts terminal, single. Other characters the same as
in Sphcerozyga. Spores originating in cells placed just below
the heterocysts.

Cylindrospermum macrospeimum. Kutz. Tab. Phyc. I., t. 98,

f- *•

Trichomes curved or nearly straight, pale blue green, more
or less interwoven ; joints globose or elliptic, often mixed with
others somewhat cylindrical, either homogenous or granular.
Heterocysts terminal, elliptical. Spores elliptic oblong, or
oblong cylindrical, green or yellowish brown, darker brown
when mature, granular, twice as long as broad.

2 M

244 NEMATOGEN.E.

SIZE. Cells -003 -'004 mm., heterocysts rather longer.
Spores -014 x '025--03 mm.

Kirch. Alg. Schl. 237. Kabh. Alg. Eur. ii., 186.
Anabaina impalpeb rails, Hass. Alg. 283, t. 75, f. 3.

In ditches and ponds.

Plate XCV. fig. 1. Trichomes with heterocysts and spores X 400.

Cylindrospermum catenatum. Ralfs Ann. Nat. Hist. t. 8,f. 14.

Stratum bluish green. Trichomes very fine elongated
straight, or slightly flexuous, generally parallel, moniliform.
Joints sphserical minute. Heterocysts oval. Spores 2-8 in
each series, at first spherical, then more or less oval, but little
broader than the heterocysts.

SIZE. Cells about -003 mm., heterocysts a little longer,
spores about '006 x '008 mm.

Rabh. Alg. Exs. No. 1358.

In fresh water.

Clearly distinguished from the preceding species by its nu-
merous spores.

Plate XCV. Jig. 2. Trichomes with heterocysts and spores X 400.

GENUS 99. NODULAR! A. Mertens. (1822.)

Trichomes distinctly vaginate, with very closely compressed
disc-shaped joints, collected in a gelatinous or menibranaceous
irregularly diffused stratum. Heterocysts intercalated at re-
gular intervals, vegetative joints nearly equal, transversely
compressed. Spores fuscous, or golden yellow, becoming tawny,
globose, slightly compressed.

Nodularia litoiea. (Thw.) Thur. Ann. Sci. Nat 1875, 378.

Scarcely gelatinous, forming a deep green fleecy covering to
floating plants on which it occurs. Trichomes of considerable
diameter, nearly straight. Joints of a beautiful blue green
colour, very short and compressed, giving the filaments the ap-
pearance of an Oscillaria. Heterocysts pale reddish. Spores
elliptical, at length acquiring a deep brown colour.

SIZE. Trichome, without sheath, -012 mm.

Born, and Thur. Notes Algol, ii., 121, t. 29, f. 1-9.

Spermosira litorea, Kutz. Phy. Gen. 213. Rabh. Alg. Eur.
ii., 186. Harv. Phy. Britt. t. 113, f. c.

In muddy, brackish ditches.

NOSTOCE.E. 245

Plate XCV. fig. 3. a, portion of triohome, with heterocysts X 400 ;
b, portion X 600 ; c, fertile portion, with spores X 600 ; d, spores X GOO ;

e, spore germinating, after Thuret.

Nodulazia Harveyana. Thur. in Ann. Sd. Nat 1875, 378.

Trichomes much curved, composed of cells nearly as long as
broad. Heterocysts subquadrate, rather longer than wide, and
of the same width as the joints. Spores spherical, almost
twice the diameter of the joints.

SIZE. Trichomes -0065 mm. diam.

Born, and Thur. Notes Alg. ii., t. 29, f. 14-16.

Spermosira Harveyana, Thw. in Harv. Phyc. Britt. t. 173,

f. c. Eabh. Alg. Eur. ii., 295.

In brackish ditches.

Plate XCV. Jig. 4. «, portion of trichorne with heterocysts X 400 ; b,
the same X 600 ; c, portion of trichome with spores X 600 ; d, germi-
nating spoi'es, after Thuret.

FAMILY II. LTNGBY^J.

Filaments without heterocysts, and destitute of a terminal
hyaline hair, single, and scattered, or numbers associated in
bundles and enclosed in a common sheath, often radiating.
Joints shortly cylindrical, disc -shaped in section.

GENUS 100. SFZRULINA. Link. (1834.)

Trichomes articulated, spirally twisted, motile, nestling in a
more or less liquid colourless matrical mucilage. Propagation
unknown.

Consult Cohn in Nova Acta Car. Leop. vol. xxiii. Braun in Botauische
Zeitung 1852, p. 395. Keinicke Beitr. zur neuern Mikrosk ii., pp.
1-56.

Spirulina Jenneri. Kutz. Tab. Phyc. i., t. 37, J. 11.

Trichomes more or less elongated, distinctly articulated,
spirals lax, distant, joints equal in length to their diameter, or
a little shorter. Cell-contents pale or bright blue green.

SIZE. Trichomes -OOT-'OOS mm. diam.

Rabh. Alg. Eur. i., 90. Kirch. Alg. Schl. 250.

Spirillum Jenneri, Hass. Alg. 277, t. 75, f. 5.

Arthrospira Jenneri, Hedwigia i., p. 32, t. 5.

In stagnant water.

Plate XCV1. fig. 1. Portions of trichomes X 400,

246 NEMATOGKNJL.

Spixulina oscillaxioides. Tt/rp.

Solitary, or forming little green tufts, sometimes almost
radiating. Trichomes more or less elongated, nearly erect, pale
blue green, twisted in lax or dense spirals, endowed witli active
motion.

SIZE. — Trichomes -0015--002 mm. diam.

Kutz. Tab. Phyc. i., t. 37, f. 8. Rabli. Alg. Eur. ii., 91.
Kirch. Alg. Schl. p. 250. Cohn Nova Acta xxiv., t. 15, f.
15.

var. 1. xninutissixna. RaJili. Alg. Eur. ir., 91.

Trichomes abbreviated, more loosely spiral.
Spirillum minutissimum, Hass. Alg. 278, t. 75, f. 8.
Spirulina brevis, Kutz. Tab. Phyc. i., t. 37, f. 9.

In fresh, brackish, or thermal waters.

Plate XCVI. fig. 3. Portions of trichomes X 400. Fragment
further magnified.

Spirulina tenuissima. Kutz. Spec. Alg. 236.

Forming a membranaceous, lubricous, dark blue green floating
stratum, trichomes very thin, flexuous, very densely spiral, en-
dowed with active motion ; joints very indistinct.

SIZE. — Trichomes very thin. Spirals '005 mm. diam.

Rabh. Alg. Eur. ii., 92. Harv. Phyc. Britt. t. 105, f. c.

In brackish ditches.

Floating in large blue green masses on the surface of brackish ditches.
The threads are too delicate for measurement, and appear only as lines
under a magnifying power of 400 diameters.

Plate XCri. fig. 2. Portions of trichomes X 400.

GENUS 101. OSCILLARIA. Bosc. (1800.)

Trichomes simple, usually distinctly articulate, rigid, straight,
or a little curved, rarely circinate or spirally convolute, for the
most part brightly "coloured (blue-green, steel-blue, violet,
ceruginous, &c.), motile, nestling in a matrical mucilage; joints
disc-shaped in the front view, without a sheath distinct from
the trichome.

Consult Dr. d'Alquen in Quart. Journ. Micr. Sci. iv. (1856), p. 245.

The species are at present distinguished by very artificial characters,
which are by no means permanent, in which respect the genus is not in a
much better condition than it was forty years ago.

247

Oscillaiia tenexxima. Kutz. Tab. Phyc. i., t. 38, f. 8.

Solitary and scattered, or associated in fascicles. Trichomes
straight, indistinctly articulate, joints equal in length to their
diameter, or a little longer or shorter, ends somewhat acute,
slightly inclined ; cell-contents pale blue green, or olive, homo-
genous or very finely granular.

SIZE. Threads -0018--0025 mm. diam.

Rabh. Alg. Eur. ii., 96.

In ditches, amongst decaying vegetable matter.
Plate XCVI. fig. 4. Trichomes X 400.

Oscillaxia leptotxicha. Kiitz. Tab. Plujc. i., t. 38, /. 9.

Solitary, scattered, or collected in a very thin bine green
stratum, trichomes very slender, slightly curved, indistinctly
articulate, joints twice as long as broad, or after division equal,
very minutely punctate at the periphery, attenuated at the ends,
which are straight, curved, or deflexed, cell-contents pale blue,
green, homogenous or finely granular.

SIZE. Threads -003 mm. diam.

Rabh. Alg. Eur. ii., 97.

In fresh or brackish ditches.
Plate XCVI. fig. 5. Trichomes X 400.

var. splendida. ("Grev. Fl. Edin. 304. J

SIZE. Trichomes not exceeding -002 mm. diam.
Oscillatoria splendida, Eng. Fl. v., 375. Harv. Man. 164.
Hass. Alg. 251, t. 72, f. 8.

In tubs of water in a stove. Edinburgh Botanic Gardens.
Plate XCVI. jig. 6. Trichomes X 400.

Oscillaxia spixalis. Carm. Harv. Phyc. JBritt. t. 105s.

Effused in a firm coriaceous glossy black stratum. Trichomes
radiating, slender, long, flexuous, regularly twisted in spirals.
SIZE. Threads -0035--004 mm. diam.
Spirillum rupestre, Hass. Alg. 277, t.^75, f. 6.
Spirulina rupestre, Rabh. Alg. Eur. ii., 93.

On rocks by the seaside.

" It spreads over the dry naked earth. Stratum several feet in extent,
firm, coriaceous, of a glossy black colour, void of lubricity. Filaments
about half a line in length, twisted like a corkscrew, radiating 111 all di-
rections." — Carmichael.

Plate XCVIII. fg. 7. Trichomes X 400, from the original specimens.

248 NEMATOGEN^E.

Oscillaria zubiginosa. Carmichael Alg. App. ined.

Stratum gelatinous, dark purple; trichonies very thin, straight,
indistinctly articulated, laid on a thin, compact, greenish sub-
stratum.

SIZE. Threads -004-'0045 mm. diain.

Oscillaria violacea, Rabh. Alg. Eur. ii., 113. Eng. Fl. v.
377.

OsciUatoria violacea, Hass. Alg. 254, t. 72, f. 10. Harv.
Man. 166. Johnst. Fl. Berw. ii., 264.

Conferva mucosa confragosa rivulis innascens, Dillen (?)

Rapid streams, and on stones at the bottom of rivers.

When dry the filaments of this species assume a blackish green cast,
with an evident gloss. Strige when dried almost invisible, at a distance
of about two diameters from each other. — Hassall.

As another species is called Osdllaria violacea (Wallr), which has
priority, the name proposed by Carmichael must be adopted.

Plate XCrill. fig. 0. Portions of trichomes X 400, from the original
specimens.

Oscillaria subfusca. Vauch. Conf.I$3,t.l5,f.5.

Forming a very thin, greenish brown, then blackish stratum,
shortly radiating. Trichomes equal, straight, curved at the
apex (curvature of 4 to 5 joints), joints about equal in length to
their breadth (after division shorter), dissepiments very dis-
tinctly granulate, extreme apical point fimbriate, or bearded.
Cell-contents pale greenish steel-blue, granular.

SIZE. Threads '0045-'006 mm. diam.

Rabh. Alg. Eur. i., 100. Kirch. Alg. Schl. p. 246. Mack.
Hib. p. 240. Eng. Fl. v., 377. Harv. Man. 166.

OsciUatoria subfusca, Hass. Alg. 253, t. 72, f. 9.

Attached to wood, rocks, stones, &c., in streams.

"Stratum extensive, soft, slimy, void of tenacity, wrinkled, of a
dusky grey colour, when dry greyish-brown, streaked with green to-
wards the edges ; filaments very slender, striae invisible." — Harvey.

Plate XCVL fg. 7. Portions of trichomes X 400.

Oscillaria aerugescens. Drumm. Ann. Nat. Hist. (1838) i,p. I.

Stratum of a fine deep green, highly gelatinous, when dried
aeruginous blue, and glossy ; trichomes very slender, opaque
green, conglomerated in large masses, rarely floating, or broken
into fragments and suspended like cloudy flocculi in the water,
joints about half their diameter long.

SIZE. Trichomes '005 mm. diam.

OsciUatoria aerugescens, Hass. Alg. 249, t. 72, f. 2. Harv.
Man. 163.

LYNGBY.E. 249

In lakes and pools.

This is the species which Dr. Drummond described as the " colouring
substance of Glasslough Lake, Ireland." He commences by skating that
" Glas-lough " signifies " green lake," an appellation given to it from
time immemorial on account of the hue of its waters, which exhibit a
green tinge, equal to, or exceeding in intensity, that of the sea, though
it is not at all times equally striking. " From the accounts I received,
the green colour is evident in the lough throughout the year, and if I
may judge from my own observations, every drop of it is impregnated
with the oscillatory filaments." " When a little of the water is lifted in
the hand it seems perfectly transparent, and it appears equally clear at
the edges of the lake, but at a depth of two feet the bottom is indis-
tinguishable, and the water presents a sort of feculent opacity, accom-
panied by a dull, dirty, greenish hue. On lifting some of this in a glass
it seems at first sight quite transparent, but on holding it up to the light
innumerable minute flocculi are seen floating through every part of it,
and producing a mottled cloudiness throughout the whole." "At first I
could only find the plant diffused through the water, but at length I dis-
covered a wet ditch extending from the lake into an adjoining field, and
there it appeared swimming on the surface in large masses several inches
in thickness, and above a foot and a half in length. These seemed evi-
dently to be produced by an agglomeration of the filaments floated in
from the lake, matted together at the surface, and increased in growth.
The surface of these masses, where dried by the contact of the air, was
of a bright bluish verdigris hue, while the parts immersed in the water
were of a dull opaque green.

"On examining specimens in the microscope, I sometimes observed
their motions to be very vivid, and in other instances little or no motion
could be perceived. They are extremely minute, their transverse striae
very numerous, and at distances of about half a diameter from each
other. The filaments in the conglomerated masses appeared to me to be
many inches long, and running parallel together ; the broken fragments
dispersed through the lake cross each other in all directions."

Plate XCVlll. fig. 5. Trichomes from specimen collected by Drurn-
moud X 400 diain.

Oscillaxia tenuis. Ag. Syst. Alg. p. 60.

Forming a bright green, or dark blue green stratum, shortly,
or elongated radiating. Trichomes straight, rather rigid, more
or less endowed with active motion ; joints equal or half as
long as broad, sometimes a little constricted at the dissepi-
ments, which are delicately granulated ; apex more or less
attenuated, obtuse, curved or straight ; cell-contents pale
watery blue.

SIZE. Threads '054--006 mm. diam.

Rabh. Alg. Eur. i., 102.

Oscillatoria limosa, Hook Fl. Scot, ii., 79.

Oscillaria viridis, Kutz. Tab. Phyc. i., t. 41, f. 6. Eng. Bot.
t. 2523. Johnst. Fl. Berw. ii., 264.

Oscillatoria coritexta, Carrn. Hass. Alg. 256, t. 71 , f. 7, 4,
6. Eng. Fl. v., 376. Harv. Man. 165.

Oscillatoria tenuis, Hass. Alg. 248, t. 72, f. 1. (?) Jenn.
Tunb. Wells 188. Harv. Man. 163. Grev. Fl. Edin. 303.

250 NEMATOGEN.E.

Mack. Hib. 239. Gray. Arr. i., 281. Eng. Fl. v., 374. Eng.
Bot. ii., 2525.

In ditches, swamps, inundated places, now and then free
swimming ; throughout the year.

Yery variable, passing into several moderately distinct varieties, of
which the bright green one called viridis is the most beautiful, and by
no means rare.

The form which Carmichael called Oscittatoria contexta has thus been
described by him : — " Stratum of indefinite extent three feet and up-
wards, exceedingly thin, and peeling off in large flakes in dry weather,
of a deep but shining black colour, scored or striated in all directions.
These strise are caused by thick fasciculi of filaments, shooting out
either parallel to or across each other, changing their course from time
to time and sending off lateral fasciculi. The filaments are rather thick
about a line in length, straight or variously curved, of a greyish green
colour, and they radiate with great rapidity. A portion of the stratum,
not more than a line in diameter, placed in a watch-glass filled with
water, overspread the whole area of the glass with filaments in the
course of a night." Hassall says of it, " the filaments are in calibre not
less than those of O. tenuis, from which species it is distinguished
chiefly by its colour."

Plate XCVL fig. 8. Portions of trichomes X 400. Plate XCVTI,
Jig. 1. Portions of trichomes of the variety viridis X 400.

Oscillaxia antliaiia. Jury ens Alg. Exs. No. 14.

Expanded in a gelatinous, sometimes very broad submem-
branaceous stratum, dark steel-blue. Trichomes rigid, straight,
sometimes tranquil, sometimes oscillating, curved at the attenu-
ated apex (curvature of 3 to 4 joints) ; joints equal, or nearly
equal,in length and breadth (after division half as long), dissepi-
ments distinctly granular, extreme apex obtusely rounded. Cell-
contents pale steel-blue, or blue green, nearly homogenous.

SIZE. Threads -0045-'0055 mm. diam.

Kutz. Tab. Phyc. i., t. 40, f. 6. Rabh. Alg. Eur. ii., 100.

Oscillaria parietina, Vauch. Conf., t. 15, f. 8.

Around pumps, cisterns, &c.
Plate XGyll. fig. 2. Portions of trichomes x 400.

Oscillaria muscorum. Carm. HSS.

Stratum 3-4 inches, of a dark bluish-green colour, slightly
lubricous, shortly radiating, creeping over mosses. Trichomes
variously curved, pale blue green, joints about equal in length
to their diameter.

SIZE. Trichomes *006-'007 mm. diam.

Hook. En^. Fl. v., 365. Harv. Man. 164. Hass. Alg.
252, t. 72, f. 12.

In rapid streams, on Hypnum ruscifolium, &c.

" Stratum 3 or 4 inches in extent, closely interwoven with the branches
and leaves of mosses, of a bluish green colour, and slightly lubricous

LYNGBY^E. 251

Filaments a line or two in length, variously curved and radiating j
strias at the distance of a diameter from each other." — Carmichael.

Plate XCVII1. fig. 8. Portions of triohomes X 400, from the
original specimens.

Oscillaxia subuliformis. Thw. in Harv. PJiyc. Britt.

Stratum of an intense eeruginous green. Trichomes bright
green, subuliform, gradually attenuated towards the apices, which
are subacute and much curved ; joints about three-fourths as
long as broad, homogenous.

SIZE. Trichomes -006-' 007 mm. diam.

Harv. Phyc. Britt. t. 251 B. Eabh. Alg. Eur. ii., 292.

In brackish ditches. Summer and autumn.
Very bright emerald green, and certainly an attractive species.

Plate XCV1II. fig. 3. Trichomes from original specimen X 400
diam.

Oscillaxia limosa. Ag. Syst. Alg. 66.

Trichomes rigid, straight, actively oscillating, blue-green,
interwoven in a thin mucilaginous radiating green stratum,
distinctly articulate, joints nearly equal or a little longer than
broad (shorter after division, often half as long as the dia-
meter), dissepiments granulated, apex obtuse, straight or
curved ; cell-contents pallid, homogenous or slightly granular.

SIZE. Threads f008-'01 mm. diam.

Eabh. Alg. Eur. i., 104. Hook. Br. Fl. ii., 374.

Conferva limosa, Fl. Dan. t. 1549.

Oscillatoria limosa, Hass. Alg. 246, t. 71, f. 2. (?) Eng. Fl.
v., 374. Gray. Arr. i., 280. Eng. Bot. ii., 186. Harv. Man.
162. Johnst. Fl. Bervv. ii., 265. Mack. Hib. 239. Fl. Dev.
ii., 56.

Oscillaria tennis d. limosa, Kirch. Alg. Schles. p. 247.

There are several varieties, differing chiefly in colour, of which Raben-
horst enumerates ten.

If Hassall's figure is magnified in proportion to the rest, then his t. 71,
f . 2, can scarcely be the present species, for its diameter would be equal
to that of 0. Frolichii, whereas this scarcely exceeds half that thickness.
All the figures of Oscillaria given in Hassall's work are acknowledged to
be very defective.

Plate XC VII. fig. 3. Portions of trichomes X 400. Fig. 4, portions
of trichomes of the variety ckalybea X 400.

Oscillaxia ixxigua. Kutz. Phyc. Gen. 189.

Stratum thin, expanded, compact, dark steel-blue, by oblique
light purplish violet ; trichomes straight, flexile, pallid then
livid steel blue, a little attenuated at the apex, joints equal in
length to their diameter (after division half as long) dissepi-

2 N

252 NEMATOGENJE.

ments beautifully granulated, extreme apex broadly rounded, or
somewhat beaked, cell-contents homogenous or delicately
granular.

SIZE. Threads '0076--01 mm.

Kutz. Tab. Phyc. i., t. 42, f. 4. Rabh. Alg. Eur. ii., 107.

On wet rocks, walls, or overrunning mosses.

The variety " subsalsa," bearded at the apex, was found on Greenwich
Pier in 1861.

Plate XCril. fig 5. Portions of trichomes X 400.

Oscillaria nigra. Vauch. Cow/. 192, t. 15, f. 4.

Stratum more or less compact, somewhat membranaceons,
often floating, steel-blue, or dark olive nearly black, with radii
more or less elongated, of the same colour. Trichomes straight
or slightly flexuous, obtusely rounded at the apex, or attenuated,
and sometimes bearded ; joints equal in length to their diameter
(after division one half or one third as long) ; dissepiments very
distinctly granulated, apiculus often straight, somewhat rostel-
late and bearded, rarely slightly curved ; cell-contents pale olive,
finely granular.

SIZE. Threads *009-'01 mm. diaun.

Rabh. Alg. Eur. i., 107. Kirch. Alg. Schl. 247. Harv.
Man. 165. Eng. Fl. v., 376. Eng. Bot. t. 2527.

Oscillatoria rdgra, Hass. Alg. 255, t. 71, f. 3. Hook. Fl.
Scot. 79. Jenn. Tunb. Wells 188. Mack. Hib. 239. Gray
Arr. i., 281.

Conferva fontinalis, Ih'llw. Conf. t. 64. Huds. Fl. Aug.
592. Lighlf. Fl. Scot. 976. With. Arr. iv., 1^8.

In ditches and ponds.

" Stratum extensive, blackish, with a shade of green, when dry bine-
black, very rapid in its growth, and sending out long, vividly oscillating
rays.'' — Harvey.

Plate XCVII.fg. 6. Portions of trichomes X 400.

Oscillaria nigro-viridis. Thwaites in Harv. Phyc.

Stratum thin, of a dark olive green, almost black, growing
upon the mud, and subsequently floating in large masses.
Trichomes pale dull green, with obtuse, distinctly curved,
scarcely attenuated apices ; joints indistinct, about half as long
as broad, cell-contents slightly granulose.

SIZE. Trichomes '012 mm. diam.

Harv. Phyc. Britt. t. 251 A. Rabh. Alg. Eur. ii.. 292.

In brackish ditches. August.
Plate XCVII1. jig. 2. Trichomes of O. nigro-viridis X 400 diam.

LYNGBY,E. 253

GscilJaria chalybea. Mertens, in Jurgens Alga.

Floating. Stratum broadly expanded, with long radii, dark
blue green or steel-blue, shining ; trichomes pale steel-blue,
slightly flexuous, a little attenuated at the apex, joints three or
four times shorter than their diameter, a little contracted at the
dissepiments, which are not granulated, apiculus slightly curved,
obtusely rounded, now and then rostellate, cell-contents pale
steel-blue, granular.

SIZE. Threads -OOSS-'Ql mm. diam.

Kutz. Tab. Phyc. i., t. 40, f. 8. Rabh. Alg. Eur. ii., 108.

In still and stagnant water.

The specimens figured were collected from a tank in one of the stoves
of the Hoyal Botanic Gardens, Regent's Park.

Plate XCV11I. Jiff. 1. Trichomes of O. chalylea X 400 diam.

Oscillaria Frolichii. Kutz. Phyc. Gen. 189.

Stratum dark steel-blue, or at first olive, then dark blue,
often elongated, radiating, opaque, shining ; trichomes nearly
equal, straight ; joints 2, 3, or 4 times shorter than their
diameter, with a double series of granular points more or less
dense at the junction, often confluent, so as to resemble a single
series; apiculus broadly rounded, straight, or declined; cell-
contents blue, becoming steel-blue, homogenous.

SIZE. Threads -015-'018 mm. diam.

Kutz. Tab. Phyc. i., t. 43, f. 1. Rabh. Alg. Eur. ii., 109.

Oscillatoria mucosa, Hass. Alg. 247, t. 71, f. 1.

In ditches, pools, and boggy places, sometimes amongst
mosses.

The finest of the species yet detected in Britain.
Plate XCVII. f. 7. Portions of trichomes X 400.

Oscillaria insignis. Thwaites in Phyc. Britt.

Stratum thin, .covering decayed vegetable matter at the
bottom of a ditch, with a dark-brown coating, becoming some-
what greenish in drying ; trichomes very large, rather brittle,
their apices rounded, somewhat oblique, and furnished with
numerous motionless cilia ; cell-contents distinctly granulose.

SIZE. Trichomes '018 mm. with sheath.

Rabh. Alg. Eur. ii., 293. Harv. Phyc. Brit, ii., t. 251, f. c.

In a brackish ditch. November.

A portion of the trichome from the original specimen has been
figured, but Professor Harvey was evidently of opinion that it was a
strictly marine species. There seems at least to be no doubt that it is

254 NEMATOGEN.E.

in reality a Lyngbi/a, allied to L. cestuarii, and not a true Oscillaria.
We are indebted to Professor Percival Wright for an examination of
authentic specimens of this, and several other of Harvey's species.

Plate XCVllI.Jly. 4. Portion of trichome X 400.

Doubtful Species.
Oscillaria Dickiei (Hass.) Rabli. Alg. Eur. u., 113.

Stratum pale chesnut-brown, gelatinous, shining ; trichomes
of medium size, long, straight, fragile, with visible spaces
between the joints.

SIZE. Not determined.

Oscillatoria Dickiei, Hass. Alg. 258, t. 72, f. 13.

Pools of fresh water near the sea.

The colour of this species is so peculiar as at once to distinguish it
from all others which have been described. This colour is preserved in
drying; the filaments are of nearly the same diameter with those of
0. tennis, but they preserve their calibre when dried. — Bassall.

Oscillaria thermalis. (Hass.) Eabh. Alg. Eur. n., 113.

Trichomes straight, rigid, fragile, green ; divisions of the
joints distinct, rather remote.
SIZE. Not determined.
Oscillatoria thermalis, Hass. Alg. 250, t. 72, f. 3.

In warm water.

The figures and descriptions in Hassall's work are wholly insufficient
for the proper identification of this and the following species.

Oscillaria vizescens (Hass.) Rabh. Alg. Eur. n., 113.

Stratum pale blue-green ; trichomes of medium size, pale
yellowish-green, with the joints rather distant, nearly equal in
length to their diameter.

SIZE. Not determined.

Oscillatoria virescens, Hass. Alg. 250, t. 71, f. 9.

On the ground.

GENUS 102. MICROCOLEUS. Desm. (1823.)

Trichomes rigid, articulate, crowded together in bundles,
enclosed in a common mucous sheath, either closed or open at
the apex ; sheath ample, colourless, more or less lamellose,
rarely indistinct. = Chthonoblastus, Kutz. (1843.)

LYNGBY^E. 255

" Trichomes enclosed in a transparent sheath from which they emerge to
reproduce new filaments, sheath containing several trichomes. Fila-
ments growing in scattered creeping erect or floating wick-like bundles." —
Thtiret.

Hydrocoleum tliermale Kutz., mentioned in Quart. Journ. Micr. Sci.
(1867) p. 86, as having occurred in Ireland, we have never seen, and,
therefore, do not know whether it should be included in Microcoleus.

Microcoleus gracilis. Hass. Alg. 261, t. 70, /. 2.

Effused broadly in a thin dark green stratum. Trichomes
pale blue green, slightly curved, in fascicles densely contorted
about the apex, joints 2-3 times longer than their diameter,
either continuous or distinctly separated, granulated, divisions
paler, nearly hyaline, a little contracted about the apex, extreme
apiculus conical, now and then slightly carved, special sheath
narrow, very delicate, universal sheath very thick lamellose.

SIZE. Trichomes •0025--003 mm. ; fascicles •09-*12 mm.

Kirch. Alg. Schl. 244.

Microcoleus marinus, Harv. Man. 168.

Chthonoblastus salinus, Kutz. Tab. Phyc. i., t. 58, f. 2. Rabh.
Alg. Eur. i., 133.

Oscillatoria chthonoplastes, var. a. Eng. Fl. v., 373. Eng.
Bot. ii., t. 2523. Mack. Hib. 239.

On salt marshes.

"Fronds fixed at the base, floating freely in the water, an inch long,
tufted, dichotomously branched, branches slender capillary widening up-
wards, with club-shaped tips ; colour olivaceous green or yellowish.
When ruptured the branches discharge innumerable needle-shaped fila-
ments, which, when the plant is growing, radiate and oscillate from the
tips of the branches." — JJarvey.

Plate XCIX. fig. 1. End of fascicle of trichomes with sheath X 400.

Microcoleus chthonoplastes. Thur. in Ann. Sci. Nat. (1875)

p. 377.

Stratum thin, or thicker and rather compact, dingy seru-
ginous green ; trichomes slightly flexuous, equal, twisted, in
dense fascicles, joints nearly twice as long as their diameter,
rather remote from each other, leaving a hyaline space between
them, apiculus attenuated, rather elongated ; special sheath
very delicate, universal sheath narrow, scarcely lamellose.

SIZE. Trie-homes •>0035-'004 mm. ; fascicles -03--035 mm.

Chthonoblastus Lyngbyei, Kutz. Tab. Phyc. i., t. 58, f. 1.

Microcoleus anguiformis, Hass. Alg. 261, t. 70, f. 1. Kirch.
Alg. Schl. 244.

Chthonoblastus anguiformis, Kutz. Tab. Phyc. i., t. 57. Rabh.
Alg. Eur. ii., 133. Harv. Phyc. Britt. t. 249.

On the naked ground, by roadsides, &c.
Plate C.fiy. 1. Fascicle of trichomes with sheath X 400.

256 NEMATOGEN^E.

BTicrocoleus terrestiis. Desm. PI. Crypt. Exs. i., No. 55.

Stratum more or less expanded, deep blue green or steel blue,
or olive, becoming brownish, membranaceous, mucilaginous ;
trichomes equal, collected in filiform i'ascicles, sometimes much
elongated, extruding from the opening of a common sheath in a
penicillate manner, joints equal in breadth and length, dissepi-
ments granulated, apiculus acute, straight.

SIZE. Trichomes -005--006 mm.; fascicles 'OTS-'OS mm.

Kirch. Alg. Schl. p. 244.

Chthonoblastus repens, Kutz. Tab. Phyc. i., t. 54. Rabh. Alg.
Eur. ii., 132.

Microcolevs repens, Hass. Alg. 260, t. 70, f. 3. Jenner Tunb.
Wells 188. Harv. Man. 168.

Conferva vaginata, Eng. Bot. i., t. 1995.

Oscillatoria chthonoplastes, var. p. Eng. Fl. v., 373. Mack.
Hib. 239.

Vaginaria vulgaris, Gray. Arr. i., 280.

Vaginaria chthonoplastes, Grev. Fl. Ed. 305.

On moist naked ground.

" The frond consists of numerous curled branches diverging from a
centre in a starry manner, and gradually tapering from a broad base to a
fine point, containing numerous deep green filaments, which radiate and
oscillate from the tips, and, on laceration, issue in bundles."-— Harvey.

Plate. XCIX. fig. 2. End of fascicle of trichomes with sheath X 400.
GENUS 103. INACTIS. Kutz. (1843.)

Trichomes vaginate, indistinctly articulate, parallel and fasti-
giate, now and then dichotomous, very densely aggregated and
agglutinated in a pulvinate thallus.

" Filaments bundled, erect, growing in small rounded tufts, or in a
felt-like turf of indefinite extent. Trichomes very slender."— Thuret.

Inactis Cresswelli. Thur. in Ann. Sci. Nat. (1875) 377.

Forming convex roundish or oval patches, which become con-
fluent for several inches ; filaments hyaline, yellowish or greenish
olive, collected into dense rope-like branching bundles, which
are fastigiate ; trichomes exceedingly slender, once or twice di-
vided in a dichotomous manner.

SIZE. Trichomes "0025 mm. diam.

Schizothrix Cresswelli, Harv. Phyc. Britt. t. 160. Rabh.
Alg. Eur. ii., 268.

Spreading over the surface of soft sandstone rocks exposed to
the drip of fresh water.

LYNGBY.E. 257

" Mr. Cresswell states that it prows at the very top of high water mark,
in situations where it is exposed to the continual drip of fresh water
falling from high mural cliffs, and that it is most luxuriant where the
drip falls from the greatest height, which in the station observed is about
fifty feet." — Harvey.

Plate C. Jig. 2. a, portion of fascicles of trichomes X 100 ; b, tri-
chomes X 400.

Inactis tinctoxia. Thur. Ann. Sci. Nat. (1875) 377.

Fasciculate csespitose, dingy brown becoming olive ; trichomes
single or many associated in one sheath, joints equal in length
to their diameter or a little longer; sheaths broad, colourless,
distinctly lanaellose, even.

SIZE. Trichomes '002 mm. diam.

Hydrocoleum tinctorium, Br. Rabh. Alg. Ear. ii., 294. Ralfs
Exs., No. 19.

On aquatic plants.

Mr. Marquand says that he has never seen it growing on any other
plant than Scirpvs fluitans, .and he adds : — " I have never seen a vestige
of green about it in its natural condition during any period of its exis-
tence ; when decaying it becomes pale, and eventually almost white ;
when in its best condition it is of a rich chesnut brown. In drying it
turns green. In its best condition, when placed in water for twelve hours,
it will dye it of a clear rosy purple."

The following description of this plant has been kindly furnished by
Mr. Kalfs : — " In rapid streams on leaves of aquatic plants, it forms a
minute continuous covering on leaves of aquatic grasses, giving them a
feathery appearance. Colour varying from nearly black to pale reddish
brown ; in drying and decay it turns green, and gives a purplish stain to
paper. Filaments somewhat mucous, very slender, nearly colourless,
cohering at base in fascicles containing 3 to 8 filaments, and by their
separation at intervals, simulate branches, and thus gradually reduce the
number cohering until they ultimately separate into single ones. The
filaments thus appear comparatively stout at the base and gradually to
become attenuated upwards. As the apparent branches are given off this
is more especially the case, because, from their pale colour, indistinct
endochrome, and closeness of connection, it requires care to detect that
they are really fascicled. Besides the elongated filaments there are
numerous short ones at the base, together with crowded, somewhat
thicker clavate erect bodies. Whether these are the fructification or
rudimentary fascicles I am unable to determine." — Ralfs.

Plate C.fig. 3. Upper portion of fascicle of trichomes X 400.

GENUS 104. LYNGBYA, Ag. em. Thuret. (1875.)

Filaments enclosed singly in a sheath, simple, or only excep-
tionally exhibiting the beginning of ramification where the
trichome issues from the side of the sheath ; often combined in
a membranaceous stratum. — including Phormidium Kutz.

258 NEMATOGENA.

Lyngbya aestuarii. Lieb. Danska Alg flora. (1839.)

Trichomes rigid, flexuously curved, blue green, granular,
densely interwoven in dark blue green tufts ; joints 3-6 times
shorter than their diameter ; scarcely constricted ; sheaths
pellucid, hyaline, becoming brownish, at first scarcely larnellose,
at length when old becoming distinctly lamellose.

SIZE. Trichomes '025--03 mm. diam., without sheath.

Lyngbya ceruginosa, Ag. Syst. p. 74. Rabh. Alg. Eur. ii.,
138.

Lyngbya ft. ferruginea, Harv. Phyc. Britt., t. 311.

Lyngbya curvata, Rabh. Alg. Eur. ii., 137.

Lyngbya majuscula, Cocks Brit. Seaweeds No. 365.

In brackish water.

Plate CL fiff. 1. a, portion of filament X 160 diam. J, extremity
of filament, with portion of trichome escaped X 160 diam. c, portion of
filament with the trichome divided into hormogones X 330. d, e, hormo-
gones X 330, all after Thuret.

Lyngbya littoralis. (Carm).

Stratum thin, submembranaceons, mucilaginous, blue green,
shortly radiating ; trichomes rigid, flexuous, vividly oscillating,
equal ; joints 4-5 times as broad as long, constricted at their
junction and hyaline, dissepiments granulated, extreme apiculus
straight, broadly rounded, paler ; cell contents pale blue green,
very delicately granular.

SIZE. Threads '013--015 mm. diam.

Oscillatoria littoralis, Carm. Alg. App. ; Eng. Fl. v., 375.
Harv. Man., 165. Harv. Phyc. Britt. t. 105, fig. a.

In brackish water, and in rock pools by the shore.

" Stratum exceedingly thin, slimy, bullated by the extrication of air-
bubbles, of a dark green colour, spreading to an indefinite extent over
the muddy bottom of the pool." — Carm.

Plate Gil. Jig. 1. Portions of trichomes X 400, from the original
specimens.

Lyngbya ochracea. Thur. Ann. Sci. Nat. (1875) 377.

Forming cloud-like floating fragile masses of an ochrey
colour. Trichomes very slender, scattered ; joints scarcely
visible.

SIZE. Trichomes '002 mm. diam., including sheath.

Kirch. Alg. Schl. 241.

Leptothrix ocliracca, Kutz. Tab. Phyc. i., t. 61, fig. 1.

Conferva ochracea, Dillw. Conf. t. 62.

LYNGBY.E. 259

Oscillatoria ochracea, Grev. Fl. Edin. 304. HaiT. Man.
167. Eng. Fl. v., 378. Eng. Bot. ii., 187. Johnst. Fl.
Berw. ii., 264. Mack. Hib. 240. Fl. Dev. ii., 57. Gray.
Arr. i., 281.

In boggy pools.

This species is common in boggy pools " where it occurs in cloud -like
masses, scarcely to be called strata, the filaments are very slender and
scattered without order. Dillwyn's figure incorrectly represents the
filaments as branched."

Plate CII. fig. 4. Trichomes X 400.

Lyngbya inundata. (A'wfo.)

Deep blue green, with a whitish grumous mernbranaceous
substratum, trichoines curved rather rigid, pale blue green,
rarely fasciculate, sheaths narrow, joints shorter than their
diameter, dissepiments naked (not granulated), extreme apex
straight obtuse.

SIZE. Trichomes '004 mm. diam.

Phormidium inundatum, Kutz. Tab. Phyc. i., t. 45, f. 3.
Eabh. Alg. Eur. ii., 116.

Oscillaria autumnalts, Carm. (partly). Harv. Man. 165. Hass,
Alg. 251, t. 72, f. 7.

Margin of ditches, by moist roads, on flowerpots, &c.

" Stratum extensively spreading, very dark and lubricous, glossy when
dry, filaments remarkably pale, stiise not very evident, a variety is com-
mon on clayey ground, which occurs in small circular patches about an
inch or two in diameter.'' — Harveij.

The filaments in Carmichael's specimens are not more than half the
diameter of those in Lyngbya vulgaris, to which species they are usually
referred,

Plate GIL fig. 8. Portions of trichoines X 400.

Lyngbya vulgaris. Kirch. Alg. Schl.2^2.

Stratum thin, more or less expanded, mucilaginous, dark
coloured (olive, brown, yellow, steel blue or purplish) opaque or
shining, by age becoming thickened, but rarely lamellose, and
without a substratum being formed ; trichomes straight, rigid,
distinctly vaginate, joints equal to their diameter or shorter,
dissepiments delicately granulated, apex evidently attenuated,
now and then somewhat curved, naked.

SIZE. Trichomes -0045- -0065 mm. with sheath -006--009 mm.

Phormidium vulgare, Kutz. Tab. Phyc. i., t. 46, fig. 4. Rabh,
Alg. Eur. ii., 119.

2 o

260 NEMATOGEN-ffi.

Osdllatoria autumnalis (partly), Eng. Fl. v., 376. Fug. Bot.
ii., 187. Jenn. Tunb. Wells 188. Grev. Fl. Edin. 305.
Harv. Man. 165, Mack. Hib., 239.

Conferva decorticans, Dillw. Conf. t. 26.

Osdllatoria decorticans, Grev. Fl. Edin. 304. Eng. Fl. v.,
375. Eng. Bot. ii., 187. Jenner Tunb. Wells 188. Harv.
Man. 164; Mack. Hib. 239. Hass. Alg. 257, t. 71, f. 10.

Hv mid a decorticans, Gray. AIT. i.; 282.

On moist naked ground after rain.

Plate OIL fig. 5. Portion of trichonies X 400 ; fig. Q, variety
myocliroum x 400.

Lyngbya papyxina. Kirch. Alg. Schl. 241.

Forming a thin papery stratum, sometimes shortly radiating,
with a pallid or brownish fibrillose substratum, formed from
the interlaced empty sheaths, trichonies equal, joints nearly
equal or a little shorter than their diameter, granulated at their
junction, apex obtuse, straight, naked.

SIZE. Trichomes -005--006 mm., with sheath -0075--009.

Oscillaria papyrina, Bory. Diet. Sci. Nat.

Phormidium papyrinum, Kutz. Tab. Phyc. i., t. 41, fig. 3.

Phormidium papyraceum, Rabh. Alg. Eur. ii., 125.

Osdllatoria spadicea, Carm. Hass. Alg. 255, t. 71, f. 5, t.
72, f. 5. Eng. Fl. v., 378. Harv. Man., 167.

In streams, torrents, aqueducts, canals, &c.

The form met with by Carmichael was growing 011 clamp mossy earth.
He says " It occurs in a very thin dark green stratum spreading to the
extent of several feet, and is hardly to be distinguished from the mossy
earth on which it grows."

Plate C1I. fig. 7. Portions of trichomes X 400.

Lyngbya xupestxis. (Ag.)

Stratum compact, rather velvety, gelatinous, lamellose, very
shortly radiating, bright blue green or becoming dark steel blue,
the lower strata becoming discoloured and fibrillose ; trichomes
rigid, rather flexuous, a little torulose towards the apex, joints
equal in length and breadth, very finely punctate, dissepiments
granulated, extreme apex paler, sometimes bearded.

SIZE. Trichomes >007-*008 mm. diani.

Phormidium rupestre, Kutz. Tab. Phyc. i., t. 49, fig. 4. Rabh.
Alg. Eur. ii., 122.

Oscillaria rupestris, Ag. Syst. p. 63. Hass. Alg. 254., t.
72, f. 11. Grev. Sc. Crypt, Fl. t. 246. Eng. Fl. v., 377,
Harv. Man. 166.

LYNGBY^E. 261

On moist rocks where the water is constantly trickling, and in
mountain streams.

Carmichael writes of his specimens, " Stratum extensive, slimy, re-
markably tough and elastic, black on the surface, ash-coloured under-
neath, when dry blackish green. Filaments pale green, straight, or
variously curved, radiating, but not equally in all directions."

Plate CI. fig. 2. Portions of trichomes X 400.

Lyngbya corium. (Ag.)

Stratum toughly membranaceous, compact, brown, steel blue
or greenish, interwoven forming a mucilaginous membrana-
ceous substratum ; trichomes straight or flexuous, rather rigid,
olive or brown, then yellowish, joints not more than half as long
as broad, beautifully transversely punctate, granulated, apex
conically attenuated, bearded.

SIZE. Trichomes •007--OOS mm. diam.

Phormidium corium, Ag. Syst. p. 64. Kabh. Alg. Eur. ii.,
126.

Oscillatoria corium, Hass. Alg. 252. Eng. Fl. v., 377.
Harv. Man. 166. Eng. Bot. ii., 187. Grev. Fl. Edin. 303.
Mack. Hib. 240.

On the rocky bottom of alpine rivulets.

" Stratum thick, tough, dull brownish, occasionally streaked with pale
green, which in some varieties is the prevailing colour, slightly glossy
when dry ; filaments slender. In some situations it radiates in fascicles
from its whole upper surface ; in others it is found almost denuded
of radii, and forming a compact leathery stratum." — Harvey.

Plate CI1. fig. 2. Portions of trichomes X 400.

Lyngbya turfosa, (Carm.)

Forming a thick intensely green stratum, with a tough, slimy,
ochre-coloured substratum. Trichomes slender, more or less
curved, and mostly hyaline at the point ; joints not more than
half as long as broad, distinct.

SIZE. Trichomes '008 mm. diam.

Oscillatoria turfosa, Carm. in Harv. Man. 164. Hass. Alg.
253, t. 72, f. 6.

On floating sods in old turf pits.

" This species grows in a thick, intensely green layer, over a tough,
slimy, ochre-coloured substratum. It entirely enveloped the sods, some
of which were a foot and a-half in diameter. Filaments very slender,
more or less curved, and mostly hyaline at the point." — Carm.

Plate Cll. fig. 3. Portions of trichomes X 400, from the original
specimens.

262 NEMATOGEN^E.

Lyngbya subfusca. (Ag. Syst. p. 64.)

Substratum velvety, fibrillose, tawny, becoming yellowish,
forming a firm compact stratum, of a violet or steel blue colour,
changing to brownish ; trichomes rigid, straight, joints about
half as long as broad, with a double row of points at the com-
missure, apex rather obtuse, naked.

SIZE. Trichomes -008 mm. diam. Thinner form, trichomes
•006--007 mm. diam.

Phormidium subfuscum, Rabh. Alg. Eur. ii., 125.

On stones in mountain streams.

Plate CI. fig. 3. a, portions of trichomes X 400, from Scotch speci-
ens. J, portions of trichomes from a thinner form X 400.

mens

GENUS 105. SYMPLOCA. Kutz. (1843.)

Trichomes articulate, simple, or only exhibiting the beginning
of ramification, more or less distinctly vaginate, ascending from
a prostrate base, agglutinated, together in erect or anastomos-
ing fascicles, or wick-like bundles, more or less procumbent,
coalescing, and often involved in a matrical gelatin.

Symploca lucifuga, Harv. in Eng. Fl. V., 373.

Dark seruginous green, fascicles about two lines high, ap-
proximate, subuliform, apex at length penicillate ; trichomes
single or twin, serugmous, joints equal or a little longer than
broad, distinctly granulated, sheaths broad, pellucid, colourless,
quite smooth.

SIZE. Trichomes *0035-'004 mm. diam., including sheath
•01 mm.

Rabh. Alg. Eur. ii., 155.

Oscillator ia lucifuga, Hass. Alg. t. 65, f. 5, 6. Harv. in
Eng. Fl. v., 373.

Calothrix lucifuga, Carm. MSS.

On pastures and heaths, on decayed alder trunk.

" Stratum spreading dull blackish green, bristling all over with minute
erect fascicles about one third of a line high. Filaments thickish,
flexuous, strongly agglutinated together, annulated within, pale
yellowish." — Harvey.

Plate CHI. fig. 2. a, portion seen with a pocket lens, b, trichomes
X400.

LYNGBY^E. 263

Symploca Ralfsiana, Kutz. Tab. Phi/c. i, t. 74, /. 4.

Steel blue or olive becoming blackish, fascicles as much as
an inch high, densely aggregated, often coalescing, subuliform,
straight, trichomes pale blue-green or steel blue, densely
agglutinate, distinctly articulated, somewhat beaded about the
apices, joints equal or a little longer than broad, cell-contents
granular, sheaths broad, pellucid, homogenous.

SIZE. Trichomes '0035-'004 mm. diam.

Kabh. Alg. Eur. ii., 157.

Oscillaria Friesii, Harv. Eng. Fl. v., 373. Harv. Man.
162. Hass. Alg. p. 259. Mack. Hib. 238.

Oscillatoria Bangii, Carm. Grrev. Fl. Ed. 303.

Scytonema Bangii, Lyngb. Hydro. Dan. t. 28.

Over running mosses in shady sub-alpine situation.

" Stratum 2-3 inches broad, bright aernginous green; Filaments
closely interwoven into erect elongated tooth-like fascicles, an inch or
more in height, pale green under the microscope, annnlated within, with
a broad limb or border, well marked by its erect spinulose habit." —
Harvey.

•

Plate GUI. Jig. 1. a, portion as seen with a pocket lens. 6, trichomes
X 410.

GENUS 106. PLECTONEMA. Thur. (1875.)

Filaments branched, ramifications produced by the branching
of the trichome outside of the sheath, very irregular, and often
germinate as in Scytonema.

Flectonema mirabile, Thur. Ann. Sci. Nat. (1875) 377.

Forming floccose tufts, blue-green, now and then turning
brownish, trichomes with pseudo-branches usually in pairs and
parallel ; joints shorter than their diameter, granular sheath
narrow, colourless or yellowish, quite smooth.

SIZE. Filaments '021 mm. with sheath.

Born, and Thuret, Notes Alg. ii., p. 135, t. 33.

Conferva mirabilis, Dillw. Conf. t. 96.

Calothrix BreUssonii, Kutz. Tab. Phyc. ii., t. 30, f. 4.

Calothrix atrovirens, Harv. Man. 159.

Calothrix mirabilis, Ag. Syst. 72. Rahh. Alg. Eur. ii.,271.
Hass. Alg. 243, t. 69, f. 1. Eng. Fl. v., 369. Harv. Man. 159.

Elisa mirabilis, Gray. Arr. i., 283.

In small streams.

•

Plate CIV fig. 1. a, portion of trichome X 330. &, portion with
a single branch X 330 after Thuret.

264 NEMATOGEN^E.

Plectonema Kirchneri, CooTce, Grevillea XL, p. 75.

At first attached, but soon floating, and forming subglobose
woolly tufts, of a dark bluish green, changing to olivaceous.
Tufts from half an inch to an inch in diameter. Trichomes
radiating, with simple (rarely germinate) branches ; joints one
third or one fourth as long as broad.

SIZE. Filaments '012-'015 mm. diam., with sheath.

Plectonema mirabile, Kirch. Alg. Schles. p. 229 (scarcely of
Thuret).

In ornamental water. Pleasure grounds, Kew.

The filaments are much thinner than in P. mirabile and the branches
issue singly from the sheath, and not in pairs, as in that species. From
the dimensions given by Kirchner it seems probable that this is the
species to which he has given the name of P. mirabile.

Plate CIV. fig. 2. a, tuft, natural size, b, trichomes X 400.

FAMILY III. SCYTONEME^E.

Filaments with lateral ramifications in which some of the
cells change into heterocysts.

This family is divisible into two sections according to the direction
of the multiplication of the cells.

: Cells only multiplying in the direction of the length of the filament.

Scytonema, Petalonema, Symphyosiphon, Tolypothrix,

Cystocoleus.

** Cells multiplying as well in the direction of the breadth of the
filament, at least where the branches, which are always produced by
lateral multiplication, originate.

Stigonema, Fischera, Haplosiphon.

The last section includes many very doubtful forms, which will pro-
bably, as their development becomes better known, be transferred to
Lichens, of which they are presumably an imperfect condition.

GENUS 107, SCYTONEMA. Ag. (1824.)

Sheath enclosing a single trichome, ramifications produced
by the deviation of the trichome, which emerges from the side
of the sheath. Ramifications usually geminate, produced by a
fold of the trichome which ruptures outside of the sheath, and
gives origin to two filaments given off at a right angle.
Heterocysts scattered here and there in the trichome, without
any evident relation to the ramifications.

SCYTONEMEJE;. 265

Scytonema myochrous. Ag. Syst. p. 40, No. 13.

Stratum thin, woolly, dark brown (now and then rather
silky) ; trichomes very thick, brown, lucid, slightly curved,
ascending, blue-green within, reddish at the apex (5-6 terminal
joints), distinctly articulate, pseudo-branches for the most part
in pairs, sometimes very long, flaccidly erect, about half the
thickness of the trichomes ; sheath of the trichomes thick, dis-
tinctly lamellose, '.firm, beautiful yellow-brown, surface quite
smooth, that of the branches paler, often colourless at the tips,
closed and obtusely rounded, heterocysts oblong or sub-cylindri-
cal, colourless, about equal to the inner diameter of the
trichomes.

SIZE. Cells '01 mm. diam., with sheath -03 mm. diam.

Rabh. Alg. Eur. ii., 254. Hass. Alg. 237, t. 68, f. 2.
Jenn. Tunb. Wells, 188. Gray. Arr. i., 285. Eng. Bot. ii., t.
2515, t. 2516. Kirch. Alg. Schl. 225. Harv. Eng. Fl. v.,
365. Harr. Man. 155. Mack. Hib. 236.

Conferva myochrous, Dillw. Conf. t. 19. Eng. Bot. i., t.
1555.

On moist rocks.

Plate CV. fig. 1. a, threads magnified about 60 diam. ; b, portion of
same X 400 ; c, hormogones X 400.

Scytonema natans. Breb. in Kutz. Tab. Phyc. II., t. 22, /. 1.

Floccose tomentose, green then brown or olive, trichomes
slender, elongated, becoming brownish, internally seruginous
green, distinctly articulate, joints nearly equal, granular, pseudo-
ramuli often in pairs, very slender, more or less distant, very
shortly articulated, sheaths firm, lamellose, yellow or brownish,
rarely uncoloured, branches paler, or colourless, indistinctly
lamellose, heterocysts interspersed, oblong, or ovoid, pellucid.

SIZE. Threads with sheath '025 mm., without sheath '007
mm.

Rabh. Alg. Eur. ii., 253. Kirch. Alg. Schl. 224.

In stagnant water.
Plate CV. fig. 2. Portion of trichome with sheath X 400 diam.

Scytonema cinereum. Meneg. in Kutz. Spec. 303.

At first pulvinate, cinereous green, then confluent, forming a
more or less tomentose pulverulent stratum (becoming pale blue
when dry), now and then violet or purplish ; trichomes very
fragile, elongated, flexuose and curved, loosely interwoven,
sparingly branching, indistinctly articulate, internally dingy,

2 P

266 NEMATOGEN.E.

aernginous green, joints shorter than broad ; sliuaths thick,
golden brown, often encrusted with deposit of lime.

SIZE. Trichomes '008 mm., including sheath -01 mm.

Kirch. Alg. Schl. 225. Rabh. Alg. 'Ear. ii.. 247.

Scytonema Juliannm, Wittr. & Nordst. Alg. Exs.,-No. 273 a.

Drilosiphon muscicola, Kutz. Sp. 302.

Oscillaria cyanea, Hass. A.lg. 248. Eng. Fl. y., 374. Harv.
Man. 163.

Conferva cyanea, Eng. Bot. ii., t. 2578.

Humid a cyanea, Gray. Arr. i., 282.

On walls, stones, overrunning moss, &c.

Found on the walls of warm houses in the Royal Botanic Gardens at
Kew, and in Regent's Park. This is evidently the Conferva cyanea of
English Botany found on damp walls in churches, &c. " On the wall it
is conspicuous for its light sky-blue colour, like some sort of Jhi'-or.
Under a high magnifier, and when moistened, it is found to consist of
minute even simple entangled threads, coated with a frequently inter-
rupted covering1 of a dull glaucous green hue, under which the thread
itself appears of a lighter glaucous bluish colour, very even in thickness,
and surface consisting of scarcely distinguishable joints about as broad
as they are long." — Smith.

Bornet and Thuret refer this to a variety of Scytonema Hoffmanni,
whilst Kirchner retains Meneghini's specific name, which Thnret thinks
to belong to Scytonema ocellatum, Lyngbye.

Plate CPl.fiy. 1. a, trichomes X 400; 1>, portions of same X 400 ; c,
hormogones X 400.

\

Scytonema interruption. Thw.

Intense blue-green, forming a stratum of the same colour ;
sheath cellular, and furnished throughout its entire length with
numerous branched and anastomosing rootlets ; trichomes dis-
tinctly annulate, interrupted here and there by heterocysts,
branches in pairs arising from the protruded trichome.

SIZE. Nowhere stated.

Rhizonema interruptwn, Thwaites in Eng. Bot. ii. Stipp., t.
2954.

Calothnx interrupta, Garni. Eng. Fl. v., 368. Harv. Man.
158.

Stigonema interruption, Hass. Alg. 229, t. 69, f. 2.

In wet heathy places, coating mosses, &c.

We have seen no specimen of this, which is evidently a close ally of
/& cinereum. The figure is reproduced from English Botany.

Plate CV1. fig. 2. Scytonema interntptum, after the figure t. 2954,
English Botany. Considerably magnified, presumably about 360 diam.

SCYTONEMEJE. 267

GENUS 108. PETALONEMA. Berk. (1832.)

Trichomes enclosed in a very broad striate membranous
sheath, which forms a transparent layer, resembling a hyaline
wing.

Threads as in Scytonema, with the sheath very broad, forming a
transparent layer around the trichome.

Fetalonema alatum. Berk. Glean, t. 7, f. 2.

Forming a thin brown stratum. Trichomes small, a few
lines only in length, winged, obtuse, with numerous stride, when
taken in conjunction with the wings or membranous expansions,
they are linear and plane. Each wing is about thrice the
breadth of the proper filament, of a white colour, somewhat
transparent, of a bright yellow next the filament, and exhibiting
under a favourable light a numerous series of transverse lines
or folds. Endochrome of the central thread greenish and
septate.

SIZE. Trichomes -01 mm., with sheath from -05 to -12 mm.

Hass. Alg. 238, t. 68, f. 6. Harv. Man. 168.

Arthrosiphon alattis, Rabh. Alg. Eur. ii., 265.

Arthrosiphon Grevillei, Kutz. JSp. Alg. 311. Fischer Nost.
f. 10.

Oscillatoria alata, Grev. Sc. Crypt, Flora, t. 222.

On rocks exposed to the trickling of water.

Plate CVII, f,f/. 1, Upper ' portion of trichome with sheath X 400
diam.

GENUS 109. SYMPHYOS1PKON. Kutz. (1843.)

Trichomes as in Scytonema. Filaments agglutinated in erect
wick-like bundles.

Symphyosiphon Hoffmann!. Kutz. Tab. Pliyc. u., £.43, /. 3.

Terrestrial, resembling a Symploca in habit. Tufts small,
ascending, dark brown ; trichomes simple, erect, loosely col-
lected in pointed fascicles, internally palo geruginous green,
sometimes interrupted, joints delicately granulose, inferior
cylindrical, thin, superior thicker and more or less swollen.
Sheath firm, broad, attenuated upwards, rarely acute, colourless,
or yellowish towards the base. Heterocysts intercalated,
globose, hyaline.

SIZE. Trichomes -01 mm. diam., with sheath -012--014 mm.

Scytonema Hoffmcnnri, Agardh Syst. p. 40. Rabh. Alg.
Eur. ii., 259.

268 NEMATOGEN^E.

On naked ground, overruning mosses, &c.

Found in some quantity in one of the stoves of the Eoyal Botanic
Gardens, Regent's Park, forming a dark velvety stratum on the stones,
walls, &c.

Plate CVII. fig. "2. a, slightly enlarged, as seen by aid of a pocket
lens ; b, trichomes X 400 ; c, portion of same ; d, hormogones X 400.

GENUS 110. TOLYPOTHR1X. Kutz. (1843.)

Trichomes spuriously branched, pseudo-branches spreading.
Ramifications rarely geminate, oftener solitary, and originating
at a point where the continuity of the trichome is interrupted by
heterocysts, one or several heterocysts placed directly above
each branchlet.

Tolypothtix flaccida. Kutz. Phyc. Gen., p. 228,

Crespitose, dark blue-green, trichomes and pseudo-branches
elongated, flaccid, arising from a prostrate base, internally pale
blue-green, either interrupted or torulose, distinctly articulate
(when treated by iodine), joints a little shorter than broad,
sheaths colourless, hyaline, rather broad, heterocysts towards
the base, subglobose or oblong, two or three together, colour-
less.

SIZE. Trichomes *01 mm.

Rabh. Alg. Eur. ii., 227. Kutz. Tab. Phyc. ii., t. 32, f. 2.

In pools, &c.
Plate CVlll.Jig. 1. Portions of trichomes X 400 diam.

Tolypothrix distorta. Kutz. Tab. Phyc. n., t. 33, /. 5.

Caispitose floccose, bright blue-green, now and then becoming
pale, trichomes and pseudo-branches very loosely interwoven,
internally blue-green, sometimes apparently continuous, some-
times distinctly articulate ; joints equal or a little shorter than
their diameter ; sheaths broad, colourless, rarely pale yellow ;
heterocysts at the base, or interjected, subglobose or oblong,
often 2-3 together.

SIZE. Trichomes '012 mm.

Rabh. Alg. Eur. ii., 275. Kirch. Alg. Schl., 228.

Conferva distorta, Dillw. Conf. t. 21. Eng. Bot. t..2577.

In swamps.

"Found occasionally in boggy pools, growing on thick continuous
tufts, on decaying grass, and about the steins of aquatic plants, upon
small fragments of which it often floats in the autumn on the surface of
the water."

Plate CVI1I. fig. 2 Portion of trichome with hormogone x 400 diam.

SCYTONEME^E. 269

Tolypothzix aegagropila. Kutz. Tab. Phyc. u., t. 32, /. 3.

Tufts an inch or more broad, somewhat rounded, bright blue
green or greenish olive ; trichomes and pseudo-branches loosely
interwoven, internally pallid blue green, continuous or dis-
tinctly articulate, joints equal or a little longer than their
diameter ; sheaths narrow, hyaline, colourless, heterocysts 2
or 3 (rarely more) in a series, oblong, hyaline.

SIZE. Trichomes •01-<012 mm.

Rabh. Alg. Eur. ii., 274. Kirch. Alg. Schl., 227.

Tolypothrix punctata, Hass. Alg. 240, t. 69, f. 3.

In standing pools.

Plate ClX. fig. 1. Portion of trichome with hormogones X 400 ;
b, c, hormogones after Thuret ; d, e, spores, after Borzi.

var. e, pygmsea. Kutz.

Tufts small, blue green or brownish, trichomes and pseudo-
branches slender, very losely interwoven, joints a little shorter
than broad, sheaths narrow, colourless or yellowish.

SIZE. Trichomes '007-'008 mm, with sheath *01 mm.

Kirch. Alg. Schl., 228.

Tolypothrix pygmcea, Kutz. Tab. Phyc. ii., t. 31, f. 4. Rabh.
Alg. Eur. ii., 275.

Plate ClX. Jiff. 2. Portion of trichomes with hormogones X 400.

var. /, muscicola. Kutz.

Casspitose, blue green or brownish, trichomes and pseudo-
branches thicker, elongated, loosely intricate, distinctly articu-
lated, points a little shorter than broad, sheaths very delicate.

SIZE. Trichomes '008-'011 mm.

Kirch. Alg. Schl., 228.

Tolypothrix muscicola, Kutz. Tab. Phyc. ii., t. 31, f. 5. Rabh.
Alg. Eur. ii., 275.

On mosses, &c.

Tolypothrix coactilis. Kutz. Tab. Plujc. n., t. 32, /. 1.

Fasciculate, caaspitose, green then brightly aaruginous, tri-
chomes and pseudo-branches slender, internally pallid,
asruginous, sometimes distinctly, sometimes indistinctly articu-
late, granulose, joints about half their diameter in length ;
sheaths very narrow, very thin, homogenous, colourless, hya-
line ; heterocysts oblong, twin or ternate, colourless.

SIZE. Trichomes '01 mm., with sheath a little more.

Kirch. Alg. Schl., 228. Rabh. Alg. Eur. ii., 274.

Tolypothrix distorta, Hass. Alg. 240, t. 69, f. 4. Eng. Bot.,
t. 2521. Ralfs. Alg. Ex. No. 20.

270 NEMATOGEN.E.

Conferva distorta, Dill. Conf., t. 22, /. A. E
Calothrix distorta, Harv. Man. 158. Mack. Hib. 237.
Elisa distorta, Gray. AIT. i., 282.

In ponds and lakes.
Plate CIX. fig. 3. Portions of Trichomes x 400.

Tolypothrix cirrhosa. (Carm.}

Floating csespitose, olive, or blue-green, becoming brownish ;
trie-homes nearly simple, rather stout, distinctly articulate,
pallid blue-green, joints finely granular, one-half or one-third
as long as broad; sheaths moderately narrow (rather broad in
some of the older trichomes), indistinctly lamellose, smooth ;
heterocysts scattered.

SIZE. Trichomes •012-'014mm., with sheath -02--025 mm.

Scytonema cirrhosum, Garni. Eng. Fl. v., 366. Harv. Man.,
155 (not of Eng. Bot. ii., t. 2920).

Arthronema cirrhosum, Hass. Alg. 238, t. 68, f. 7. Rabh.
Alg. Eur. ii., 267.

In mountain lakes.

" It forms flexuous tufts of brown, very slender threads, proceeding in
fascicles from membranous sub-erect sheaths, and containing a single
row of cells scarcely so long as broad." — Carm.

Plate CV11I. fig. 3. Portions of trichomes X 400; a, hormogone
X400.

APPENDIX.

Although included by Thuret and Bornet, and also by
Kirchner, with Alga3, it can scarcely be doubted that all the
members of the genera Stigonema (or Sirosiphori) and Hapalo-
siplion must be transferred to the Lichens. They are included
here in the form of an appendix, for the satisfaction of students,
who would naturally expect some reference to them in a work
of this kind. At the same time we have availed ourselves of
the opportunity to add figures, and descriptions, of two or three
uncertain species, which have been recorded as British, under
new and unknown genera.

GENUS 111. STIGONEMA. Ay. (1824.)

Cells of the trichome often geminate or ternate, in conse-
quence of their lateral multiplication, or even forming trans-
verse, several-celled bands. Sheath large. Ceils surrounded
with a thick membrane, very prominent in the old filaments.
Hormogones originating in lateral branchlets formed of a single
row of cells.

SCYTONEME^E. 271

. Stigonema ocellatum. Thur. Ann. Sci. Nat, 1875, I., 377.

More or less expanded, woolly-toinentose, dark olive brown,
cells of the trichome for the most part biseriate, sub-globose,
or oblong-compressed, equal or one -third as long as broad,
filled with a granular blue green plasma; sheaths very thick,
lamellose, dark golden brown, external stratum now and then
paler, cells of the branches for the most part uniseriate, ocell ate,
sometimes much elongated, apex obtuse, rounded, seldom again
branched, sheaths colourless or yellowish, quite smooth.

SIZE. With sheath about '04 mm. Cells '01--012 mm.

Kirch. Alg. Schl. 230.

Sirosiphon ocellatus, Kutz. Tab. Phyc. ii., t. 37, f. 2. Rahh.
Alg. Eiir. ii., 286.

Hassallia oceUata, Hass. Alg. t. 67, f. 2, 7, 6. Fischer
Nost., fig. 11.
, Conferva ocelluta, Dillw. Conf. t. D. Eng. Bot. i., t. 2530.

Sct/touema ocellattim-, Haw. Eng. Fl. v., 364. Harv. Man.
154. Grev. Fl. Ed. 302. Gray. Arr. i., 285. Eng. Bot. ii.,
t. 2514.
CLCti l£*30.*l XT , KenrwAogcrvt**. ifO-tOit

On inundated ground, in swamps and moors.

Plate CX. fig. 2. Portion of extremity of trichome X 400.
Stigonema Bouteillii. (Breb. Ann. Sci. Nat.}

•*.

Tufts small, immersed, cushion-like and rounded, dark brown,
trichomes very short, variously curved and contorted, olive, or
golden brown, sparsely branched, sometimes simple, internally
sometimes interrupted, formed from one series of cells one-third
or one-fourth as long as broad, branches unilateral, very short,
arched, sheaths narrow, colourless or very pale yellow, hyaline
and even, or with the outer stratum falling away in fibrils.

SIZE. Trichome •04-t 06 mm. Cells '01, with envelope '02
mm.

Sirosiphon Bouteillii, Breb. & Desm. in Ann. Sci. Nat. ser.
4, Vol. iv., p. 2.

On calcareous rocks and chalky cliffs.
Plate CX. fig. 3. Portion of trichomes X 400.

Stigonema panniforme. Kirch. Ah/. Schl. 230.

Forming a thin tomentose stratum, more or less expanded,
dark brown, trichomes ascending, very much branched, variously
curved, branches unilateral, here and there fasciculate, often ab-
breviated, rounded at the apex, internal cells pale blue green,
granulose, globose then compressed, arranged in a single, rarely

272 NEMATOGEN.E.

in a double series, sheaths narrow, brown or yellow brown, paler
at the tips or almost colourless.

SIZE. Trichomes -Q35--05 mm.

Eng. Fl. v., 363. Hass. Alg. 229, t. 66, f. 4, 5. Harv.
Man. 153.

Sirosiphon panniformis, Kutz. Tab. Pbyc. ii., t. 36, f. 2.

Scytonema panni forme, Ag. Syst. p. 39.

On rocks, stones, &c.
Plate CX. fig. 4. Portion of trichouies X 400 diam.

J&f . '• ~^U>~^T

Stigonema mamillosum. (Ag.} Kutz. Tab. Pliyc. n., t. 37, /. 4.

Forming continuous tufts several inches in diameter, branches
simple, their diameter being greatest in the middle, and beset
on all sides with mamillae of various sizes.

SIZE. Trichome -06-' 1 mm., very variable.

Kirch. Alg. Schl. 229. Rabh. Alg. Eur. ii., 291. Eng. Fl.
v., 363. Hass. Alg. 228, t. 66, f. 2, 3. Harv. Man. 153.
Mack. Hib. 236.

Rocky bottoms of sub-alpine rivulets.

Plate CXI. fig. 3. Portion of young trichome X 400, becoming more
opaque with age.

Stigonema compactum. Kirch. Alg. Schl. 230.

Forming an expanded compact tomentose dark brown stratum,
trichomes and branches ascending, a little attenuated at the
apices, obtuse, internally formed of a single, rarely a double
series of cells, which are torulose and almost moniliform,
diameter and length nearly equal, filled with a pale bine-green
granular plasma, sheaths firm, golden brown, heterocysts sub-
globose or oblong.

SIZE. Trichomes '015-'016 mm.

Sirosiphon compactus, Kutz. Tab. Phyc. ii., t. 36, f. 3. Rabh.
Alg. Eur. ii., 287. Leight. Lich. Flora, p. 9.

Hassallia compacta, Hass. Alg. 232, t. 68, f. 3.

Scytonema compactum, Eng. Fl. v., 365. Harv. Man. 154.
Grev. Ed. 302.

On wet rocks.

Plate CXI. fig. 4. Portions of trichomes X 400 diam.

yK*.
Stigonema turfaceum. (Berk. Eng. Bot. Supp. t. 2826, f. 1.)

•

Pulvinate, deep olivaceous black, 2 lines thick. Trichomes
very thick, much branched, golden yellow, becoming brownish,

SCYTONEME^E. 273

variously curved, branches polymorphous, varying in thickness
according to age, obtusely rounded at the apex, cells in several
series, from 2 to 4 rows in the ramuli, sheaths thick, yellow
brown, hyaline.

SIZE. Trichomes -025--03 mm.

Sirosiplwn pulvinatus, Breb. in Kutz. Spec. 317 (1849).
Kabh. Alg. Eur. iL, 290.

Hassallia turfosa, Hass. Alg. p. 232 (18-45). Kutz. Sp. p.
318.

Scytonema turfaceum, Eng. Bot. ii., t. 2517, f. 1.

Dematium turfaceum, Link. Spec, i., 134.

On the ground in heathy places and on rocks.

Berkeley says that this Alga was named by Klotsch as Dematium
turfaceum, Link., " which there is every reason to believe is correct."
"It is," he says, " a true Scytonema.'" As far as we have been enabled
to trace it. it seems to be the same as the Sirosipkon pulvinatus of
Brebisson. The specific name of turfaceum has undoubted priority.

Plate CXI. fig. 2. Portions of trichomes X 400 diam.

Stigonema saxicolum. (Nacg. in Kutz. Spec. 316.)

Forming a thin dark olive velvety stratum. Trichomes
minute, curved, variously branched, closely crowded into a thin
dark crust or evenly scattered tufts ; sheath narrow, fuscous,
cells in a single series, growing denser and nucleate with age.

SIZE. Trichomes -018-'02 min.

Sirosiplwn saxicola (Nag.). Johnson in Grevillea xii., p.
76. Fischer Nost. fig. 13.

On damp rocks, or rocks down which water trickles.

Plate CXI. fig. 1. Abbreviated trichomes X 400, seldom exceeding
this in size.

Stigonema minutum. Hass. Aly. 230, t. 67, f. 3, 4.

Spreading in a black suborbicular crust, or scattered in little
tufts. Trichomes minute, erect, rigid, rlexuous, fastigiate
branches short, obtuse, sheath rather broad, fuscous ; cells
usually in a single series.

SIZE. Trichomes '02- -03 mm.

Scylonema minutum, Harv. Eng. Fl. v., 365. Harv. Man.
155. Mack. Hib. 236.

On moist rocks in Alpine districts.

Figured from the original specimen of the English Flora in the Kevv
Herbarium.

Plate CX. Jiy. 1. Portion of trichome, nearly complete, X 400 diam,

2 Q

274 NEMATOGEN.T-:.

GENUS 112. HAPALOSIPHON. Nay. (18±'.>.)

Trichomes formed mostly of a single row of cells, sheath
slender. Aquatic plants, looking like Tolypotlirix.

Hapalosiphon byssoideus. Kirch. Al<j. SchL, 231.

Tufts compact, dark olive, trichomes ascending, rigid, oliva-
ceous, sparsely branched, containing cells arranged in a single
series. Cells at first rounded quadrate, equal in length and
breadth, becoming when older divided and shorter, one-third or
one-fourth the length of their diameter ; sheath very thick,
distinctly lamellose, golden yellow, attenuated and obtuse at the
apex.

SIZE. Trichomes -025--03 rum. diam. Cells -012 x "01
mm.

SirosipTion truncicola, Babh. Alg. Ear. ii., 286. Hedwigia
i., p. 47, t. ix., f. 3.

Hassaliia byssoidea, Hass. Alg. 232, t. 67, f. 5.

Scytoneuut byssoideum, Harv. Eng. Fl. v., 360. Berk. Glean.,
t. 19, f. 1. Harv. Man. 156.

On trunks of beech, &c.
J'latc CXI. fig. 5. Portions of trichomes X 400 diam.

SPECIES FOR EN (I UIR Y.

Dasygloia amorpha. Thwaites.

Gelatinous, amorphous, sheaths of the trichomes thick, muci-
laginous, cohering, slightly branched ; internal trichomes blue-
green, slender, simple, septate.

SIZE. Not indicated.

Dasi/gloia amorpha, Thwaites in Eng. Bot. ii. Supp., t.
2941. "

In bogs.

Coalescing in a solid gelatinous mass, as large as a swan's egg. The
filaments, quite at the base of the plant, have rather a membranous
than gelatinous sheath, and closely resemble those of a Lynykya, in
consequence of which the base of the mass is green, but in the centre of
the plant each filament is furnished with a very thick colourless gela-
tinous sheath, which is firmly coherent with those in contact with it.
Towards the periphery of the plant these sheaths assume a brown
colour, and become somewhat separate and distinct, rendering the sur-
face shaggy. Occasionally the tips of the filaments are wound spirally
round the portion beneath them.

Plate CXII. fg. 1. «, portion of gelatinous mass, natural size; J,
threads, with gelatinous sheaths, magnified ; c, portion of trichome, with-
out sheath, further magnified — all after Thwaites.

CALOTRICHE^E. 275

Petronema fruticulosuxn. Thwaites.

Plants densely crespitose, erect, somewhat regularly branched,
branches free, with obtuse rounded apices, and each with a
heterocyst at the base. Endochroine annulated, increasing in
diameter towards the apices of the filaments.

SIZE. Fronds "2 mm. long, trichomes '004 mm. diam.

Petronema fniticulosum, Thwaites, Eng. Bot. ii., Supp., t.
2959.

Scytonema cnistaceum, Ag. Syst., p. 39 (fide. spec, in Herb.
Hook.}.

On rocks. Winter.

" Forms a frustulose areolated olive brown crust upon the wet per-
pendicular surface of limestone rocks, to which it adheres so slightly as
to be very readily detached. The plants are densely crowded in little
hemispherical masses, which, together, produce the peculiar areolated
appearance of the crust. Each separate plant consists of a single fila-
ment at the base, which is from 1-4 or even more times tri- or tetra-
cholomously branched, and thus a furticose habit is given to the species.
Each branch has a connecting cell at its base, and sometimes one also at
about the middle of its length. The very thick cartilaginous sheaths are
of a pale brown colour towards the base of the plant but darker upwards,
except at the apices, which are frequently nearly colourless. The
endochrome is of a dull green colour, extremely narrow, and indistinctly
annulated ; towards the ends of the filaments, however, it becomes
much wider and slightly moniliform."

There is in the Kew Herbarium (Herb. Hdokerianunt) a specimen of
Scytonema crustaceunt, Ag., received from that authoiity himself — the
name written by him, which is clearly identical with Thwaites's plant, but
it could not consistently be united either with Scytonema or Stigonewa,
hence we have retained the name applied to it by Thwaites and placed
it here, subject to further investigation, its immediate allies being at
present doubtful.

Plate CXI 1. Jiff. 2. Petronema fruticidosum after Thwaites; fig. 3,
Scytonema crustaceum X 400, from authentic specimen received from
Agardh.

SUB-TRIBE ii. TRICHOPHOREJE. Filaments tapering at the top

Into a hyaline hair.

FAMILY IV. OALOTRIOHB^B.

Filaments free, or agglutinated into a definite thallus, ter-
minating at the apex in a delicate hair-like extremity. Hetero-
cysts normally present, scattered, or basal.

GENUS 113. CALOTHRIX. Ag. (1824.)

Trichomes rather rigid, straight, attached, often fasciculate ;
growing in small tufts, or forming a turf of indefinite extent.

276 NEMATOGENJE.

Calothrix. Orsiniana. Thur. Ann. Sci. Nat.

Forming a pulvinate stratum, as much as two lines in thick-
ness, dark brown, lubricous, opaque ; trichomes elongated,
branched, of nearly equal thickness, cuspidate at the apex or
obtuse, distinctly articulate, here and there moniliform ; sheaths
thick, lamellose, golden brown, from the base to above the
middle even, apical portion more or less dividing in fibrous
lamellae. '

SIZE. Trichomes with sheath -01-'012 mm., without sheath
•004--006 mm.

Kirch. Alg. Schles., p. 219.

Scytonoma cirrhosum, Berk. Eng. Bot. ii., t. 2920.

Ccenocoleus cirrhosus, Berk. Eng. Bot. ii., sub. t. 2940.

Schizosiplwn cataractce. Nag. in Kutz. Tab. Phyc. ii., t. 52,
f. 1. Rab. Alg. Eur. ii., 235.

On rocks and submerged stones.

Although we have seen no authentic specimen of Berkeley's C(enoco-
Ivus, the specimens from Ben Lawers, which we have referred as above,
appear to us to belong to the same species, as far as can be judged in the
absence of all measurement.

Plate CXI1I. fig. 1. Portion of trichorne X 400; J, small fragment
magnified with sheath from Eng. Bot. t. 2920 ; c, cells of trichome free
from the sheath.

Calothrix Dillwyni. (Hass. Alg.}

Flaccid, bluish green or brown, trichomes usually cohering in
pairs, sheaths inconspicuous, except towards the base, joints
about half as long as their diameter, heterocysts at the base of
the branches ovate or cordate.

SIZE. Trichomes -005--006 mm., with sheaths -OOS-'Ol mm.

De&monema Dillwynii, Berk. Eng. Bot. ii., Supp., "t. 2958.

ToUjpothrix Dilhvyni, Hass. Alg. 242, t. 68, f. 4-5.

Microcolens Dillwyni, Harv. Man. 169.

Conferva vaginata, Dillw. Conf., t. 99.

On mosses and moist rocks.

Plant minute, flaccid, much branched, seldom a quarter of an inch in
length, varying in colour from brown to bluish green. Filaments
usually cohering in pairs. Sheaths inconspicuous, except those of the
older filaments at the base of the plant, which become thickened and of
a reddish brown colour. Endochrome annnlated, more evidently so in
the recently formed filaments than at the base of the plant, dotted from
the presence of minute granules; joints about twice as broad as long,
the terminal one somewhat dilated and hemispherical. The branches
towards the base of the plant are seated each upon a connecting cell
(heteracyst) of an ovate or cordate form. The plant possesses other
branches formed by a dislocation of the endochrome, each separated
portion becoming elongated, the lower portion towards the apex of the

CALOTR1CHE.E. 277

plant, and the upper portion towards the base, and each parallel and
coherent with the other, and not usually separating until another dislo-
cation has taken place in the endochrome of one of them, so that the
filaments cohere mostly in pairs throughout the plant, though some-
times four or more filaments are coherent within one common sheath.
The apparent branch (which is really a portion of the original filament)
always extends beyond the filament from which it appears to be
given off."

The dried specimens, which alone we have seen, are insufficient to
determine the true relationship of this plant, hence, as well as the next,
their position must be accepted as provisional.

Plate CXIIL Jig. 2. a, natural size ; b, portion enlarged j c, d, e,
trichomes X 400 diatn. ; c and d, after Berkeley.

Species uncertain.
Calothrix (?) Smithii. (Berk, in Eny. Bot.)

Filaments red, creeping, branched, contained, with their
ramifications, within a tough, more or less permanent sheath,
which bursts irregularly, endochrome annulated, very slender,
green, joints about as broad as long.

SIZE. Not stated.

Ccenocoleus Smithii, Berk. Eng. Bot. t. 2940.

On moors.

" Forming a red rugose mat of interlacing threads on boggy soil,
where it is very conspicuous, but from which it is separated with diffi-
culty on account of the roots and fibres of heath and moss to which it
adheres.

" Threads elongated, branched laterally and acutely, their outer coat
being cartilaginous, within which fresh branches are generated and creep
within it till it is ruptured, when their free apices repeat the same
phenomena. Occasionally some of the rainuli burst through the sheath
at the base in pairs, as in genuine Scytonemata. Endochrome very
slender, green, the articulations about as broad as long." — M. J. B.

GENUS 114. RIVULARIA. Roth. (1824.)

Frond having a tendency to an hemispherical or bladdery
form. Filaments agglutinated by a more or less firm mucilage,
exhibiting a disposition to radiate from the base of the frond.
Frond usually with a well-defined outline. Heterocysts basal
(placed at the base of the principal filaments and branchlets) .
Ramifications produced by the transverse division of the
trichomes, the upper part of which detaches itself and becomes
a lateral branch! et, while the lower part, extending itself by the
side of the old tip, makes a new extremity similar to the first.
Trichomes never producing any spores.

278 NEMATOGEN.E.

Rivularia echinata. (English Botany.)

Globose, very minute, dark coloured, compact. Threads
fastigiate, attenuated upwards to the apex, closely cohering,
articulated, heterocysts basal, globose. Sheaths very narrow,
almost inconspicuous.

SIZE. Trichomes '007 mm. at base, -25 mm. long.

Chcetopliora punctiformis, Kutz. Tab. Phyc. iii., p. 4, t. 18, f.
2. Rabh. Alg. Eur. iii., 386.

Echinella articulata, Eng. Fl. v., p. 398. Eng. But, ii., t.
2555. Harv. Man. 187.

Conferva echinata, Eng. Bot. i., t. 1378.

Conferva echinulata, Gray. Arr. i., 310.

In lakes, ponds, &c.

This minute species, which was first described and figured in " English
Botany," appears to have been unknown on the Continent. We have
received it from several localities beside the original one of Ellesmere.
It is one of the Algae which are associated with the phenomenon called
" Breaking of the meres," thus alluded to by Professor Dickie in his
" Botanists' Guide'1 (p. 310) : — " For some years excursions were made
with the students of my botanical class to a loch on the estate of Parkhill,
about four miles north-west from Aberdeen. The sheet of water in
question is about a quarter of a mile in its greatest length ; on almost all
sides it is surrounded by extensive deposits of peat, with the soluble
matter of which a great proportion of the water passing into the loch is
impregnated. The locality was generally visited in the beginning of
July ; nothing particular had ever been observed till the summer of 1846,
when my attention was arrested by a peculiar appearance of the water,
especially near the edge, but extending also some distance into the loch.
Numerous minute bodies, with a spherical outline, and varying in size
from 1 24th to l-12th of an inch in diameter, were seen floating at different
depths, and giving the water a peculiar appearance. In some places
they were very densely congregated, especially in small creeks at the
edge of the loch. A quantity was collected by filtration through a piece
of cloth, and, on examination by the microscope, there could be no doubt
that the production w;;s of a vegetable nature, and a species of Rivularia;
one, however, unknown to me, and not agreeing with the description of
any species described in works to which I had access. Specimens were
sent to the Rev. M. J. Berkeley ; he informed me that the plant belonged
to the genus mentioned, and stated it to be Rivularia echinulata, Eng.
Bot. Along with it, but in very small quantity, I also found another
plant, Trichormusjlos-aquce, Bory.

" In the first week of July, 1847, the same species were obsei-yed
similarly associated, but the Tfichormus was now more plentiful, with-
out, however, any apparent corresponding diminution in the quantity of
the Rimdaria.

" In July, 1848, it was observed that the Riiularia was as rare as the
Trichormus had been in 1846 ; to the latter consequently the water of
the loch now owed its colour, which was a very dull green; the colour,
however, becomes brighter when the plant is dried. In neither of the
seasons mentioned was it in my power to make any observations on the
colour of the loch earlier or later than the date above mentioned, conse-
quently nothing can be added respecting the comparative development

CALOTRICJTEJS. 279

of the two plants at other periods of the season. Other two lochs in the
vicinity did not contain the plants alluded to.''

As these pages are being printed (July, 1884,) this alga has been sent
ns from a large pond between Haslemere and Farnbam, rendering the
water quite opaque, described as " like a mixture of pea soup and
water." See also Bornet and Flahault, " Sur da determination des
Rivulaires, &c.," in "Bulletin de la Societe Botanique de France,"
t. xxxi., p. 76 (1884).

Plate CXlV.Jig. 2. a, natural size ; 6, cluster magnified ; c, trichomes-
X 400 diarn.

Rivularia calcarea. Eng. Bot. 11. eel., t. 1799.

Hemispherical, gregarious, confluent in a very hard mamil-
lose incrnsting blue-green or brownish stratum, internally re-
peatedly zoned, zones of a darker green, trichomes rather thick,
pale blue green, slightly flexuous, distinctly articulate, ending
at the apex in a colourless hyaline point ; sheaths narrow,
colourless or brownish at the base ; heterocysts globose, lower
joints of the trichomes equal in length to their diameter.

SIZE. Trichomes *006 mm. diam.

Eng. Fl. v., 392. Harv. Man. 150.

Ainactis calcarea, Kutz. Tab. Phyc. ii., t. 63, f. 11.

Lithonema calcarea, Hass. Alg. 265, t. 65, f. 2.

Zonotrichia calcarea, Rabh. Alg. Eur. ii., 213.

Linckia dura, a calcarea, Grey. Fl. Edin. 322.

On rocks and stones in streams.

Plate, CKVI. fig. 3. a, section natural size ; b, portion with trichomes
X 400 diam.

Rivularia duxa. Kutz.

About the size of a mustard seed, rather hard, dark bluish-
green, becoming brownish or brackish ; trichomes seruginous,
variable in the same thallus, some thin and inarticulate, others
thicker, articulate and torulose, all with distinct sheaths,
lengthened at the apex into a colourless flexuous inarticnlated
thread ; lower joints as long as broad, or nearly so, upper ones
longer, all granulated ; sheath colourless, or yellowish ; hetero-
cysts rounded, oblong.

SIZE. Trichomes -OOS-'OOO mm. diam. at the base.

Limnactis dura, Kutz. Tab. Phyc. ii., t. 64, f. 1. Rabh. Alg.
Eur. ii., 211.

Rivularia radians, var. dura, Kirch. Alg. Schles. p. 223.

Attached to aquatic plants, especially Chara.

Plate C XV. fig. 2. a, natural size , b, section enlarged; c, trichomes
X 400 diam.

280 NEMATOGESLE.

Rivularia gxanulifera. Carmichael MSS.

Frond large, convex, becoming hollow underneath, fleshy,
lubricous, brownish olive, often including strong particles.

SIZE. Trichomes "006 mm. diam. at the base.

Harvey in Eng. Flor. v., 393. Harv. Man. 151. Hass. Alg.
363, t. 55, f. 1,4.

On cliffs exposed to the trickling of water.

" Fronds from a line to half an inch in diameter, often confluent, con-
vex, and at length concave underneath, fleshy, dusky olive-green, and
extremely slippery. Filaments rather thick, repeatedly dichotomous."
— Carm.

Plate CXV. Jig. 1. Trichomes, from an original and authentic speci-
men, X 400 diam.

Uncertain Species.

Rivularia botryoides. Carmichael MSS.

Fronds minute, aggregated, roundish, wrinkled, ferruginous,
cartilaginous. Trichomes dichotomous.
SIZE. Not stated.
Harvey in Eng. Flor. v., 392. Harv. Man. 150.

In streamlets, attached to rocks and stones.

" Fronds about a line in diameter, hemisphaerical, wrinkled and carti-
laginous, scattered, or running together like a bunch of grapes. Tri-
chomes cohering firmly, obscurely sti'iated, dichotomous. Colour when
fresh, black, on drying, darkly ferruginous." — Carm.

We have seen no specimen, and therefore can add nothing to the
above description.

Rivularia Crustacea. Carmichael MSS.

Crust very thin, widely spreading, filaments attenuated at the
base, fastigiately branched above the middle, olive green.
Harvey, Eng. Flora v., 393. Harv. Man. 151.
Lithonema crustaceum, Hass. Alg. 266, t. 65, f. 3.

On rocks exposed to the spray of cascades.

" Crust of no determinate extent, extremely, thin and slimy, black.
Filaments one-fourth of a line in length, attenuated at the base, fasti-
giately branched above the middle, of an olive-green colour." — Carm.

GENUS 115. ISACTIS. Thur. (1875.)

Similar to Rivularia, from which it differs in the frond being
flattened, and in the filaments being erect and parallel, and not
radiating.

CALOTRICHE^E.

Isactis plana. Thur. Notes Alg. n., p. 165.

Frond crnstaceous, plane, suborbicular or confluent, from 1 in.
to 2 feet, dull green, darker in the centre, lubricous, gelatinous.
Trichonies erect, parallel, sheaths hyaline.

SIZE. Trichomes -008 mm. diani.

Born, and Thur. Notes Algol, ii., p. 165, t. 40, figs. 1-4.

Eivularia plana, Harv. Man. 152.

Dasyactis plana, Kutz. Tab. Phyc. ii., t. 73, f. 1.

Mastigonema plana, Eab. Alg. Eur. ii., 226.

Parasitic on EnteromorpTia and other Alga3, chiefly in salt or
brackish water, or on rocks by the sea.

^ marine, but rarely on Enteromorpha, in estuaries and brackish

ditches.

Plate CXir.fig. 1. Trichonies X 350 diam.— after Bornet and Thuret.

GENUS 116. GLOIOTRICHIA. Ay. (1842.)
Trichomes pseudo-ramose, distinctly vaginate, sheaths broad,
often saccate at the base, transversely plicate. Spores originat-
ing in the lower part of the trichome.

Gloiotrichia natans. Thur. Ann. Sol. Nat. 175, 377.

Globose or angular, tuberculose, variable in size and form,
green, becoming brownish, trichomes straight, torulose, flexuous
and hyaline above ; lower joints more or less compressed. Sheath
broad, here and there constricted, colourless or yellowish. Spores
oblong, cylindrical, heterocysts subglobose.

SIZE. Trichomes 'Ol'-l^ mm. at base, with sheath ; '03 mm.
diam. Spores '013 mm., and upwards, diam., several times
as long.

Eivularia gigantea, Fischer Nost., fig. 6.

Rivularia angulosa, Kutz. Tab. Phyc. ii., t. 67, f. 2. Eng.
Bot. t. 2551. Hass. Alg. 264, t. 60, f. 1-4. Eng. Fl. v., 394.
Harv. Man. 153.

Gloiotrichia angulosa, J. Ag. Alg. Med. 8. Rabh. Alg. Eur.
i., 201. Jenner, Tunb. Wells, 190.

Gloiotrichia Boryana, Kutz. Tab. Phyc. ii., t. 68, f. 2. Rabh.
Alg. Eur. i., 201. " Ralfs. Alg. Exs., 21.

Gloiotrichia gigantea, Rabh. Alg. Eur. ii., 201.

Eivularia pruniformis, Purt. Midi. Fl. ii., 617.

Eivularia natans, Gray Arr. i., 285.

Tremella utriculata, Huds. Ang. 564.

In ditches, ponds, &c.

Plate CXVl. Jig. 1. Trichonies x 400 diam. a, homogones of same
X 400 diam.

2 R

282 NEMATOGENE.E.

Gloiotrichia pisum. Thur. Ann. des Sci. Nat. 1875, 377.

Of the size and form of a pea, sometimes as large as a cherry,
soft, even, or a little warted, dark olive-green, or brownish, tri-
chomes elongated ; the lower part blue-green, distinctly articu-
lated, the upper part setiform, colourless, and indistinctly arti-
culated, lower joints about equal in length and breadth, here
and there somewhat swollen ; heterocysts globose or subglobose.

SIZE. Trichomes -01-'012 mm. diam. at base. Spores '01-
•012 mm. diaiu., of variable length.

Kirch. Alg. Schles. 222.

Rivularia pisum, Ag. Syst., p. 25. Rabh. Alg. Eur. i. 206.
Berk. Glean, t. 11, f. 2. Eng. Fl. v., 392. Harv. Man. 150.
Mack. Hib. 235.

LinUa dura, Grev. Fl. Ed. 322. Johnst. FL Berw. ii., 261.

Physactis pisum, Kutz. Tab. Phyc. ii., t. 60, f. 3.

In ponds, ditches, &c., adhering to aquatic plants.

Plate XCVI. fig. 2. a, plants natural size ; b, trichomes of the same
X 400 diam.

CLASS III. RHODOPHYCE.E (or FLORIDE.E).

Multicellular Algas, with terminal vegetation. Thallus com-
posed of a series of cells, either singly or disposed in strata,
which are naked or corticate, of variable form, membranaceous,
crustaceous, filamentose, vertically branched, fasciculate, folia -
ceous, &c. Cell contents for the most part reddish, rarely
otherwise coloured. Reproductive organs of three kinds, very
often disposed in different plants, viz. (1) Male organs, or an-
theridia ; (2), Female organs, or cystocarps ; and (3), Tetra-
sporangia.

For the most part marine.

FAMILY I. PORPHYRACE^].

Thallus mucous-membranaceous, foliaceous or filamentose,
formed from a single stratum of cells, chiefly purplish. Vege-
tation by division of cells in two or more directions. Propaga-
tion by tetraspores.

GENUS 117. BANGIA. Lyngl. (1819.)

Thallus filamentous, terete or flattened, nearly plane, simple
or branched, for the most part purplish, lubricose, formed from
a single series of cells. Cell membrane thick, colourless, some-
times lamellose. Multiplication by the repeated division of the
cell-contents in all directions.

CHANTRANSIACE^E. 283

Bangia atro-purpturea. (Dilhv.) Ag. Syst. p. 76.

Forming lax purple tufts ; threads abbreviated, scarcely ex-
ceeding an inch long, simple, varying in thickness according to
age, joints nearly equal in length to their diameter, or one-third
as long, more or less constricted at the joints.

SIZE. Filaments -03--06 mm. diam. Cells '01 mm. long.

Rabh. Alg. Eur. i., 398. Eng. Bot. ii., t. 2413.
Conferva atro-purpurea, Dillw. Conf., t. 103. Eng. Bot. i., t.
2085.

Girardia fusco-'purpurea, /?. Gray Arr. i., 287.

Attached to wood and stones in streams.

In his most recent work Agardh advocates the removal of this genus
to the Ulvacece, on account of the absence of genuine tetraspores.

•

Plate CXVlLJig. 1. a, portion of tuft, natural size; 5, portions of
threads X 400 diam.

FAMILY II. CHANTEANSIACE^].

Forming dwarf pulvinate tufts, of a purplish-violet or steel-
blue colour. Thallus filamentous. Threads articulate, formed
of a single series of cells, branched, straight, naked, fasciculately
branched above, joints cylindrical. Propagation by immovable
spores formed at the tips of the branchlets. Tetraspores rarely
observed.

GENUS 118. CHANTRANSIA. Fries. (1825.)

The only genus in the family, with the same characters as
given above.

Chantransia violacea. Kutz. Tab. Pliyc. v. t. 44, /. 2.

Tufts bright violet, scarcely exceeding a line broad, pulvi-
nately rounded, threads straight, branches becoming erect,
radiately disposed ; joints 3-6 times as long as broad, the apical
joints rather obtuse.

SIZE. Cells -008--009 mm. diam.

Rabh. Alg. Eur. iii., 402. Kirch. Alg. Schles. 47.
Parasitic on Lemanea, Cladophora, and aquatic mosses.

Plate CXFlll. fig. 1. a> tuft natural size j b, portions of filaments X
300 diam.

284 RHODOPHYCE^.

Chantransia Hermann!. (Roth.) Kutz. Pliyc. Germ. 230.

Caespitose, pale rosy-pnrple, three lines long ; threads and
branches whip-like, straight, branchlets spreading, then ascend-
ing, joints 3-6 times as long as broad, the final joints cuspidate,
or rarely piliferous.

SIZE. Cells -009--002 mm. diam.

Ealfs. Ann. Nat. Hist. 1851, p. 403. Rabh. Alg. Eur. iii.,
402. Kirch. Alg. Schles. 46. Kutz. Tab. Phyc. v., 43, f. 2.

TrentepoliUa pvlchella (Ag.) Eng. Fl. v., 382. Eng. Bot. ii..
t. 2533. Harv. Man. p. 118. Johnst. Fl. Berw. ii., 242.
Mack. Hib. 219.

Conferva ncma, Dillw. Conf. t. 30. Gray Arr. i.,308. Eng.
Bot. i., t. 2585.

On aquatic plants in streams.

" The tufts are dense, soft, and woolly, not gelatinous, and adhere but
imperfectly to paper ; they are often confluent, their colour is reddish,
becoming tawny by age, and in drying. Filaments much branched, main
branches elongated, somewhat level-topped, fructiferous branches lateral,
numerous, short, patent, much divided. Capsules at first oval or clavate,
finally orbicular, crowded in a corymbose manner, mostly stalked.
Joints of stem 3-5 times as long as broad, those of fertile branches
shorter. Differs from C. chalylea in colour, and in its shorter joints and
more patent ramuli." — Rolfs.

Plate CXmi. jiff. 2. Portion of filament X 300 diam.

Chantxansia chalybea. (Li/ngb.} Kutz. Phyc. Gen. 229.

Csespitose, steel-blue, about an inch long. Threads radiately
disposed, aclpressed, branches straight, joints three to six times
as long as broad, spores collected in a racemose manner on lateral
branchlets.

SIZE. Cells 'Ol-'Oll mm. diam.

Ralfs. Ann. Nat. Hist. 1851, p. 304. Brit. Algre Exs. No.
11. Rabh. Alg. Eur. iii., 402.

Conferva chalybea, Dillw. Conf. t. 91.

Conferva corymbosa, Eng. Bot. i., t. 1666, f. 1.

Trentepohlia corymbifera, Eng. Bot. ii., t. 2534.

Trentepohlia pulcliella, (3, chalybea, Eng. Fl. v., 382. Harv.
Man. 118. Mac. Hib. 219.

TrentepoliUa chalybea, Johnst. Fl. Berw. ii., 243.

Ectocarpus chalybeus, Gray Arr. i., 322.

Trentepohlia pulchella, Hass. Alg. 73, t. 8, f. 2.

Rivulets, waterfalls, and on water-wheels.

" Plant laxly tufted, of an inky colour, more or less tinged with green.
Branches rather distant, level-topped, erect, their joints 4-G times longer
than broad. Fertile branches short, appressed, their joints shorter and
usually turgid. Capsules orbicular, corymbose." — Ralfs.

Plate CXIX. fig. 3. «, portion of tuft natural size ; $, portions of
threads X 300.

CHANTRANSIACEJ5. 285

Chantransia pygmaea. Kutz. Phy. Gen. 285.

Tufts rounded, about a line in diameter, dingy greenish, be-
coming reddish, violet, or steel-blue when dry ; threads proceed-
ing from a common centre, branched upwards in a somewhat
fasciculate manner, branches erect, parallel, rather adpressed ;
joints 2-3 times as long as broad, apical joints obtuse ; fascicles
lateral or terminal.

SIZE. Cells •011-'014 mm. diam.

Rabh. Alg. Eur. iii., 403. Kirch. Alg. Schles. 47. Kutz.
Tab. Phyc. v., t. 45, f. 2.

In streams and springs.

Plate CXIX. Jig. 2. a, tnfts natural size ; b, portions of filaments X
300 diam.

Chantransia investiens. Lenormand in Kutz. Sj). 431.

Parasitic, rose-red, much branched, joints many times longer
than broad, spores solitary or in pairs, lateral and terminal,
clavate or obovate.

SIZE. Cells -006 mm. diam.

Ralfs. Ann. Nat. Hist. 1851, p. 303. Ralfs. Brit. Alg. Exs.
No. 12. Kutz. Tab. Phyc. v., t. 45, f. 4.

Batrachospermwn rubrum, Hass. Alg. 113, t. 15, f, 2-3.

On Batracliospermum monili forme and B. atrum.

" Plant bright red, at first appearing as a minute reddish stain, finally
clothing the invested plant with a continuous downy covering. Fila-
ments creeping and interlacing at base, and surrounding the plant on
which it grows, much branched. Branches not attenuated, alternate,
erect, elongated ; joints very long, often twelve times as long as broad,
and filled with pink, slightly granular endochrotne. Capsules clavate or
obovate, alternate or opposite, sometimes, though rarely, opposite a
branch ; the terminal ones are more orbicular." — Halfs.

Plate CXIX. Jig. 1. Portions of filaments X 300 diam.

Uncertain Species.

Chantransia scotica. Kutz. Tab. Pliyc. v. t. 42.

Ca?spitose, about an inch long, steel blue ; threads sparingly
branched, branches rather elongated, and, as well as the
branches, somewhat divergent ; joints 2-3 times as long as
broad.

SIZE. Cells about 'OOO-'Ol mm. diam.

Rabh. Alg. Eur. iii. 402.

On old immersed wood.

We have no knowledge of this species. The figure is reproduced from
that of Katzing.

Plate CXriL fig. 2. Portion of thread X 300 diam. After Kutzing.

286 RHODOPHYCBJS.

Chantransia compacta. Ralfs. Ann. Nat. Hist. 1851, p. 304.

Plant minute, hemispherical, inky-green, firm ; filaments
much branched, joints twice as long as broad, branches erecto-
patent.

SIZE. Not stated.

On aquatic plants.

" It forms very minute hemispherical tnf ts or fronds of a dark colour,
and very much resembles a Rivularia in appearance ; the fronds are so
firm as to require considerable pressure in order to separate the fila-
ments for microscopic examination. Filaments comparatively stout,
rigid, much branched at the base, horizontal and interlacing. Branches
crowded, erecto-patent ; joints about twice as long as broad, but the
lower ones frequently shorter. Capsules orbicular, numerous, lateral,
arising from all parts of the plant, and usually on short stalks. Differs
from C. chalybea in its compact, firm habit ; more crowded branches,
shorter joints and more scattered capsules.'' — Ralfs.

Probably this is C. pyymcea, but we have seen no specimen.

FAMILY III.— BATPtACHOSPERME^E.

Dioecious algee. Thallus filamentous, articulate, branched,
violet, or violet-purple or bluish-green, covered with mucous ;
primary filament and branches composed of a single central
series of cells, and numerous external parallel continuous or in-
terrupted secondary series; either furnished with globosely or
subglobosely densely conglobate tufts, of equally distant verti-
cillate fascicles of branches, or everywhere densely covered with
simple or forked branches. Vegetation terminal,

GENUS. 119. BATRACHOSFERMUM. Roth. (1800.)

Thallus moniliform, composed of a simple series of medullary
cells, and a cortical accessory parallel series, clothed with sub-
globosely clustered fascicles of branches, which latter are some-
times more or less dispersed.

Professor Horatio "Wood has abstracted so well what is known of the
reproductive process in the Batrachosperms that we cannot do better
than quote his observations in full: "Frequently in well-advanced
Batrachosperms there will be seen scattered among the glomerules large
round, firm, dense balls, composed of a great number of small closely
attached cells. These are the reproductive bodies. According to Graf
zu Solms Lanbach (" Botanische Zeitung," 18G7, p. 161), they are the
result of sexual reproduction, and are developed from ' antheridia ' and
' trichogonia' (female organs) in the following manner :~

" The antheridia are small roundish cells full of a colourless proto-
plasm, which is remarkable for the very numerous bright granules which
it contains. They occur either scattered, or in groups, and are placed

BATRACIIOSPERMEJ3. 287

upon the upper ends of peculiar ovate cells, also filled with a colourless
protoplasm. Most frequently there is a single antheridium to the basal
cell, sometimes two ; the latter number appears never to be exceeded.
When matured the antheridia open, and allow their contents to escape in
the form of roundish or flattened bodies, which never, as far as known,
acquire cilia, and have, therefore, no power of spontaneous motion.
These bodies, which are believed to be spermatozoids, are unprovided
with anything like an external membrane, and are composed of proto-
plasm identical with that in the antheridium. While these changes are
occurring, certain cells in other localities are being transformed into
female organs, to which the name of Trichogonia is applied. These are
borne upon cells similar to those supporting the antheridia. At first they
are not markedly different from the other cells, but soon undergo a very
rapid growth. This is not, however, regular, and is not partaken of by
a band of tissue about one-third way from the basal end, so that at last
a long somewhat flask-shaped cell is produced, with a very marked con-
traction at the point indicated, separating it into two portions. The
wall of this cell is thin, but very distinct, and the cavity is filled with a
homogeneous or very sparsely granular protoplasm, which is continuous
through the narrow neck-like portion. After a time there appear one or
more large irregular vacuoles, with actively moving corpuscles in
them, and at the same time the neck appears to be stopped with a slimy
substance. Careful examination with reagents shows that this is a cel-
lulose, and that it does not completely block the passage way through
the isthmus. At this time there appear lying upon the free end of the
trichogonia globular or flattened bodies, without external membrane,
corresponding in all respects with those already described as being pro-
duced in the antheridia. The end of the trichogonium generally enlarges
at this period into a sort of roundish knob, and by and bye the end wall
between this and one of these globules becomes absorbed, so that there
is a free communication between the two. Whilst this is 'going on the
globule acquires a thin delicate coat, and there appears in it a vacuole
similar to those pre-existing in the trichogonium.

" The first result of this impregnation of the trichogonium is the de-
posit of new cellulose, and the complete blocking up of the passage way
through the isthmus or narrowed portion. Already before the fecunda-
tion the upper cells of the branches supporting the trichogonia have pro-
duced numerous branchlets, which, growing upwards, more or less com-
pletely cover that organ. After impregnation the cells near to the
trichogonium become much larger and broader, their vacuoles disappear,
and are replaced by a dense granular dark greenish-brown protoplasm.

These cells now show a great activity in the production of numerous
branches in the usual way ; but it is the upper two alone which, with the
trichogonium that they support, are concerned in the formation of the
fruit glomerules. These put out all over their surface an immense num-
ber of protrusions, which soon, in the ordinary way, become the parents
of as many twigs or branchlets, which, growing and branching precisely
as do the vegetative branches, soon become excessively crowded. The
base of the trichogonium participates also in the production of branches,
and at last a dense ball is formed of pseudo-parenchymatous tissue by
the forced adhesion of the crowded twigs. The central cells of the
glomerule thus formed are very large and bladder-like. The outer part
of the ball is composed of innumerable radiating rows of small cells, the
end cell of each branch being roundish so as to present a convex external
face.

" At maturity these cells open and allow their contents to escape as
round masses, which appear to have no membrane, but begin at once to
grow and secrete cellulose. Their after history has not been made out

288 RHODOPHYCEJS.

with absolute certainty, but they are believed to directly develop the new
plant."— Wood's fresh Water At gas of U.S., p. 218.

It is somewhat uncertain what should constitute the limits of species
in this genus, so that, with the exception of B. atrum, we have not de-
parted from the most generally accepted series, although we fail to dis-
tinguish more decided specific characters to separate B. vac/urn from B.
moniliforme than can be found between, so-called, varieties of these
species.

Batirachospermum moniliforme. Roth. Cat. Sot. in., 160.

From one inch to a foot in length, clothed with a more or less
firm gelatinous mucous, violet-brownish, reddish-brown, purple,
or bluish-green, vaguely and profusely branched, joints of the
branches similar, oblong or clavate, outer ones sometimes seti-
gerous, internodes naked, or furnished with scattered accessory
branches.

SIZE. Cellules -02--022 x -01 mm.

Rabh. Alg. Eur. iii., 405. Kirch. Alg. Schles. 45. Eng. Fl.
v. 388. Jenuer, Tunb. Wells, 176. Eng. Bot. ii., t. 25-42.
Harv. Man. 119. Johust. Fl. Berw. ii., 257. Mack. Hib. 221.
Hass. Alg. p.. 109. Hook. Fl. Scot, ii., 77. Gray AIT. i., 330.
Vauch. Conf. 112, t. 1, f. 5 ; t. xi, f. 4.

Conferva gelatinosa, Dillw. Conf. t. 32. Relh. Cant. Supp.
21. Hull Br. Fl. 332. Eng. Bot. i., t. 689. Huds. Ang. ii.,
597. With. Arr.iv., 134. Lightf. Fl. Scot. 986. Sibth. Ox.
337. Abbot. Bedf. 275.

Conferva fontana nodosa spermatis ranarum, Ray Syn. 62.
Dill. Muse. 36, t. 7, f. 42-46.

Batrachosperma ludibunda moniliformia, Bory. Ann. des Mus.
xx., t. 30, f. 1.

In streams and ditches.

Plate CXX. fig. a, portion of filament X 30 diam. ; I, portion X 200
diam.

var. setigerum. Rabh. Algce Exs. No. 854.

The extremities of the moniliform branchlets attenuated into
a long setiform thread.

SIZE. Cells -02 --024 x -01 mm.

var. pulcherrimum. Bory. Ann. des. Mus. p. 40.

About four inches long, violet or purple, the gelatinous in-
vestment less developed. Branches elongated, whorls rather
distant, globose, with the apices of the branchlets almost con-
fluent, interstitial spaces nearly naked.

SIZE. Cellules -018 x -01--012 mm.

Kirch. Alg. Schles, 45. Rabh. Alg. Eur. iii., 405.
Batrachospermum pulcherrimum, Hass. Alg. 109, t. 14, f. 1.
Batrachosperma ludibunda pulcherrima, Bory. loc. cit.

BATRACHOSPERME^. 289

" The extreme elegance of form and of colour renders this Batracho-
spermum remarkable ; its stems are rather more branched than those of
the variety confusum, and less than those of B. moniliforme, are from 2
to 3J inches long1, slender, and of an intermediate diameter. The globules
are perfectly sphaerical, distant upon the stems from each other the
length of a ray, more approximate, flattened, but always distinct in the
branches. Its colour is a clear grey, approaching to a most agreeable
violet ; this last tint becomes dominant in drying, and passes sometimes
to red."- -Hassall.

Plate CXXI.fg. a, portion of filament X 30 ; fig. b, smaller portion
X 200.

var. proliferum. Kutz.

Stem and primary branches densely set with short accessory
branchlets.

SIZE. Cellules -018 X -01 mnr, diam.

Kabh. Alg. Eur. iii., 406.

Batracliospermum proliferum, Hass. Alg. 112, t. 63, f. 1.

B. moniliforme, f3 proliferum, Carm. MSS.

" Frond solitary, or in small clusters, 1 or 2 inches long, irregularly
branched, branches divaricate, curved, or flexuous, opaque, and very
dark coloured, beset with short ramuli, which issue out from the joints
among the whorls, of eccentric filaments, and are themselves beset with
whorls. Colour grey. — Carmichael.

Plate CXJ.II. Portion of filament x 200 diam., from original speci-
men.

var. confusum. Hass. Alg. 105, t. 15, /. 1.

For the most part bright violet, 2-3-4 inches long, and simi-
larly expanded, densely involved in a gelatinous mucous, whorls
approximate, with numerous interstitial ramuli irregularly dis-
posed.

SIZE. Cellules '02--022 x -01 mm.

Eabh. Alg. iii., 405. Kirchn. Alg. Schles, 45.

Batracliospermum confusum, Hass Alg. 105.

J5atracliospermum giqanteum, Kutz. Tab. Phyc. iii., t. 23.

Batrachosperma ludibunda confusa, Bory. Ann. des Mus. xx.,
t. 29, f. 3.

" Of all Batrachosperms this acquires the greatest dimensions. Its
length is sometimes four inches and a half, its diameter equal often to
that of the culms of grasses. Its branches appear also to be less obtuse
than in the other varieties. The globules, or whorls, are so approximated
and so large that they are often confounded together in such a manner
as to be with difficulty distinguished in certain specimens which have the
aspect of B. lielmintosum. The colour of the plant is of a monse-grey,
agreeable by its transparency. The large stems approach a little upon
yellow. These tints become of a beautiful violet by putrefaction. It is
upon individuals of this variety that I made for the first time, twelve
years ago, an experiment which ought to be known ; after having many

2 8

290 RHODOPHYCE.E.

times carried from one locality to another stones bearing individuals of
this species, which continued to prosper in spite of the change of habita-
tion, I steeped many of them in lukewarm water, afterwards in boiling,
and no part of the Batrachosperm appeared, under the microscope,
to have undergone the slightest disorganization by these immersions,
and certain sprigs, replaced in their native place, continued to vegetate
after these experiments. I do not think that there exist other vegetables
which boiling water does not immediately disorganize, there are not
others that can resist temperatures so opposite." — Bory.

Plate CXXIII. Portion of filament X 200 diam.

var. Boltoni. Cooke.

This variety differs in the large size and very globose form
of the joints of the whorls. The apices are very often setiforrn.
SIZE. Cellules -025 x '02, or -022 x '018 mm.

This variety, found by Mr Thomas Bolton, of Birmingham, seems to
differ sufficiently to be worthy of notice as a distinct variety. In colour
it was a beautiful green, with a tendency to pass into blue in drying.

Plate CXXIV. Portions of a filament X 200 diam.

var. stagnate. Ag.

One or two inches long, blue or steel-blue. Whorls of the
stem confluent, of the branches distant.

Rabh. Alg. Eur. iii., 406.

Batrachosperma ludibunda stagnalis, Bory. Ann. Mus. xx.,
p. 42.

Batrachospermum stagnale, Hass. Alg. p 107.

Conferva jontana nodosa, &c., Dill. Muse. f. 44.

" This variety has great resemblance in form and diameter to con-
fusnm, ; it is nevertheless shorter, bnt as thick. Its whorls are round
and distinct ; they are more approximated the one to the other in the large
stems, about which they are sometimes even confused. Their colour is
a greenish-yellow, pale and livid." — Hassall.

var. alpestre. Shuttleworth.

Frond black, very mucous, much branched, alternately form-
ing very obtuse angles with the principal filaments . Whorls of
the stem spherical, distinct, but approximate, branches com-
pressed.

Bairacliospermum alpestre, Hass. Alg. Ill, t. 14, f. 2.

" This species is easily recognized by the eye alone, either in its recent
or dried state ; in the former its size, great lubricity, jetty black colour,
and approximate, yet for the most part, exactly sphaerical whorls, are
remarkable ; in the latter, in which also the black tint is preserved, it
may be distinguished by the multiplicity of its branches, which are,
except the primary ones, exceedingly short and irregular, and issue from
the main filaments almost at right angles, and by their non-moniliform
appearance. In drying, also, it shrinks considerably." — Hassall.

BATRACHOSPERME.E. 291

var. helmintosum. Bory Ann. d. Mus. t. 29, /. 2.

Filaments branched, pyramidal, naked below, branches simple,
subpinnate, acute whorls contiguous, compressed.

Batracliosperma helmintosa, Bory Ann. Mus. xx. p. 33.
Batrachospermum helmintosum, Hass. Alg. p. 105.

" The stems of this beautiful species scarcely exceed 2 inches in length.
They are fine, and denuded at their base, which appears yellow.
Numerous branches proceed from it ; they are somewhat subulate, and
diminish in length in such a way that they incline from the extremities
of the plant, and give it a pyramidal appearance. The whorls are com-
pressed, voluminous, horizontal, and so approximated that they cannot
acquire the globular form ; they become confused, and form round the
steins a coutimious cylinder of mucosity. The diameter of this cylinder
equals often that of the plume of a little bird. The branches are not less
thick at their insertion. The colour of the plant is obscure, of a bluish
and uncertain green." — Bory.

var. bambusinum. Bory. Ann. d. Mus. t. 29, /. 1.

Filaments sparingly branched, branches simple, cells much
elongated, whorls minute, distant.

Batracliosperina bambusina, Bory Ann. Mus. xx. p. 32.

Batracliospermum bombusinum (Bory). Hass. Alg. 103, t.
13, f. 3.

" Its colour is of the most elegant green ; but if the specimens be not
quickly prepared they very soon turn black upon the paper. From a
principal filament, 2-4 inches long, proceed many long, slender, loose
branches, simple, or having sometimes here and there scattered, very
small branches, which are never divided. The articulations of the
principal stem, and of the larger branches, are for the most part naked ;
their point of contact is dilated in such a manner as to resemble the rods
of bamboos. As to the whorls, they are rounded, smaller than those of
the neighbouring species, composed of very compact branchlets. Their
simple ramuli are likewise shorter than in the other Batrachosperms ;
three or four rounded joints compose them ; the ciliform appendage
which terminates them is remarkable. Someraniuli, shorter than those
of the whorl, cover also the inferior part of the articulations, which have
the appearance of reversed cones." — Bory.

Batrachospermum vagum. (Rotli.} Ag. Syst. 52.

Vaguely branched, 1-3 inches long, brownish or bluish-green ;
inferior internodes covered with a dense mass of branchlets, the
superior naked, or nearly so, apical joints of the branchlets
attenuated into a long bristle.

SIZE. Cellules '025 x *012 mm.

Eabh. Alg. Eur. iii., 406. Kirch. Alg. Scliles. 46. Eng.
Fl. v., 388. Eng. Bot. ii., 197. Harv. Man. 119. Hass. Alg.
109, t. 63, f. 2. Kutz. Spec. 536.

ftatracliosperma turfosa, Bory Ann. des Mus. xX.j t. 32, f. 1,

292 RHODOPHYCE^:.

" In no other Conferva is the number of the filaments so considerable
as this. Their total diameter equals that of the largest horsehair. They
divide in every direction from a little disc, ramify to infinity, observing
remarkably well the dichotomous disposition in their first division, their
branches becoming subsequently vague. Their total length extends even
to four inches.

" From their origin even to their extremity these filaments are clothed
with microscopic branches, so impacted that the whorls are not apparent
in scarcely any direction ; with a simple lens they are not better dis-
covered, from which it might be supposed that one was observing a
Thorea. It is but towards the points of the branches that, by the assist-
ance of a strong lens, they are at last distinguished. These whorls are
very closely approximated, horizontal, compressed the one upon the
other, and becoming so confused as to form around the filament, which
is green or yellow, and very flexible, a continuous down, mucous to the
touch, sometimes very pale, more frequently of a very agreeable bluish
watery green ; this colour is, moreover, deep towards the point of the
branches. As it grows old the plant tiirns yellow, and is discoloured." —
Bory.

var. keratophytum. Bory.

Beautiful blue-green, thin, very much branched, dichotomous,
with the black setaceous base naked, branches all equal, slender,
thin, apex slightly incrassated, whorls distinct.

SIZE. Cellules clavate, about -03 x '015 mm.

Batrachosperma keratophyta, Bory Ann. Mus. xx., t. 31, f. 2.

Batrachospermum suevorum, Kutz. Spec. 536.

Habit, colour, and ramification of B. vagum, but with the whorls dis-
tinct.

Plate CXXV. fig. a, portion of filament X 30 ; b, portion X 200
diam.

Batrachospermum atrum. Harv. Nan. 119.

Violet-coloured when moist, dark brown, almost black when
dry, vaguely and much branched, reaching 2 inches, whorls
abbreviated, distant ; interstitial branchlets very short, one or
two-celled.

SIZE. Cellules '012 mm. diam.

Jenner Tunb. Wells 176. Hass. Alg. 114, t. 16, f. 4.

Conferva atra, Dillw. Conf. t. 11. Hull Br. Fl. 332. Huds.
Ang. ii., 597. Eng. Bot. i., t. 690. With. Arr. iv., 134.
Gray. Arr. i., 330.

Batrachospermum detersum, Eng. Bot. ii., t. 2543.

Batrachospermum moniliforme, v. detersum, Eng. Fl. v., 388.
Mack. Hib, 221.

Batrachospermum moniliforme, var. i. atrum, Rabh. Alg. Eur.
iii., 406. Kirch. Alg. Schles. 45.

Lemanea setacea, Bory Ann. de Mus. t. 23, f. 3.

In streams and ditches*

Plate CXXV I t fig. \. a, portion of filament X 30 ; 6, portion X 200

BATRACHOSPERME.E. 293

" The articulations, or internodes, may be compared to reversed cones,
the superior part or whorls being formed of a few short, simple subu-
late filaments, which are not beaded ; in these filaments the colouring
matter chiefly resides, and it is amongst them that the glomerules are
formed ; that portion of each articulation which is below the whorl is
transparent, and beautifully exhibits the tubular and jointed structure
of the layers which invest the primary cells in all the species of the
genus Batrachospermum ; from many of these tubes short branches are
given off, which have almost the appearance of scales." — Hassall.

var. Dillenii. Bory. Ann. de Mus. xx., t. 22, f. 2.

Filaments dark brown, very thin, lower nodes remote, the
interstices beset very densely with prominent cells, upper nodes
crowded, branchlets very short, consisting of 3-4 cellules, ex-
treme apical nodes confluent.

SIZE. Cellules *012 mm. diam.

Lemanea Dillenii, Bory. Ann. de Mus. xx., 23.

Batrachospermum vagum, e. Dillenii, Rabh. Alg. Eur. in.,
407.

Conferva fontana nodosa, lubrica, nigris, Dill. Muse. t. 2, f.
46.

This is usually considered as a variety of B. vagum, but it seems more
closely allied to B. atruni, if that be really a distinct species.

Plate CXXVI. fig. 2. Portion of filament X 200 diam.

GENUS 120. THOREA. Bory. (1808.)

Thallus filamentose, attenuated at the apex, branched, purple-
brown, villose, mucous, with a solid central medullary stratum,
surrounded by dichotomously divided branchlets. — Surun genre
nouveau de la Cryptogamie aquatique, nomme Thorea.

Thorea ramosissima. Bory Ann. Mus. xx. 127.

From a hand's-breadth to a foot long, and rarely two feet,
very much branched, about the thickness of a horsehair, dark-
green, of a beautiful purple-violet when dry, ramelli spreading
horizontally, long and short alternating, articulate, joints 1-3
times as long as broad, or twice that length.

Harv. Man. 120. Hass. Alg. 65, t. 16, f. 3-4. Rabh. Alg.
Eur. iii.

Batrachospermum hispidum, De Cand. Fl. Fr. ii., 60.

Attached to wood, &c. Walton-on- Thames.

Plate CXXVIL fig. a. Small plant> natural size ; b, ramuli and spore ;
C> portion of filament X 400*

294 RHODOPHYCEJE.

FAMILY IV. LEMANEACE^E.

Fluviatile alga3. Thallus developed from a confervoid pro-
thallic filament, setaceous, almost simple, hollow, nodose, having
an internal and a cortical layer of cells. Poljspores numerous,
collected in branched moniliforrn series, germinating without
fertilization.

GENUS 121. LEMANEA. Bory. (1808.)

The only genus in the family, with the same characters as above
given.

" The dilated portions of the threads are loosely filled with the spores,
which are produced within the frond. The spores are oval, thick-walled
cells, joined together to form series, which are very much branched, so
that from a central basal row they rise as a complex bush-like mass. The
first step, according to Wartmann, in their germination, consists in the
elongation of the spore, and the projection of one end, which is soon cut
off by the formation of a transverse partition, and constitutes a new cell.
This multiplication soon develops into a branched confervoid filament. A
large number of these filaments are generally produced in one place at
one time, and form a very apparent greenish layer. Finally, certain cells
in branches of these filaments swell up and become very much broader
than their fellows, undergoing, at the same time, division so rapidly that
they become very short. By-and-bye they divide also in the direction
of their breadth, so that, instead of a simple series of cells, there arises
a compound mass. This is the beginning of the new frond. At first it
is dependent upon the parent filament, but soon acquires a root-like pro-
cess at the base, and develops rapidly into the complex cartilaginous
plant." — Wartmann, Beitrage zur Lemanea (1854).

Lemanea fluviatilis. Ag, Spec. Alg. n. p. -i.

Simple, or sparingly branched, 3-4 inches long, straight,
nodules rather remote, with about three verticillate papillse.
SIZE. Spores '04 x '025 mm.

Rabh, Alg. Eur. in., 411 . Kirch. Alg. Schles. 43. Eng. Fl. v.,
p. 322. Hook. Fl. Scot, ii., 84. Eng. Bot. ii., t. 2423. Jenner
Tnnb. Wells 176. Harv. Man. 119. Johnst. Fl. Berw. ii.,
246. Mack. Hib. 220. Gray AIT. i., 288. Hass. Alg. 72.

Lemanea. corallina, Bory Ann. de Mus. xx., t. 21, f. 2.

Conferva fluviatilis, Dill. Conf. t. 29. Hull Br. Fl. 332.
Eng. Bot. i., t. 1763. Huds. Ang. ii., 597. With. Arr. iv.,
134. Lightf. Fl. Scot. 985.

Conferva fluviatilis lubrica setosa equiseti facie, Dill. Muse. 39,
t. 7, f. 47.

Nodularia fluviatilis, Grev. Fl. Ed. 300. Fl. Devon, ii., 57.

Attached to stones, wood, &c,, in streams.

LEMANEACE.E. 295

" From a cartilaginous disc, stixmgly applied to foreign bodies, proceed
a great number of close filaments, elastic, of a brownish-green colour,
and a little curved at the base, but they become more pale and straight
in the remainder of their length. These filaments are ordinarily from 4
to 7 inches in length. Some are entirely simple, the others throw out
here and there branches, or divide towards the middle of their length.
The internodes are oblong, from a line to a line and a half, cylindrical,
and inflated at their points of contact. Their divisions are often but little
apparent, and disappear towards the base of the filaments, which appear
continuous, cylindrical, and equal in diameter to a strong horse-hair.
The surface of the filaments in old age is encrusted in such a manner as
not to become recognizable either by its colour, which changes, or by the
destruction of the internodes, which become confused and disappear." —
Bory.

Plate CXXV1II. fig. 1. Filaments natural size ; a, portion of fila-
ment magnified ; b. section of same ; c, chains of spores x 200.

Lemanea toxulosa. (Roth.) Ag. Spec. n. 4.

Nearly simple, for the most part bent like a bow, 1-2 inches
long, nodules approximate, papillad flattened, sometimes con-
fluent or almost obsolete.

SIZE. Spores '04- x -022--03 mm.

Kabb. Alg. Eur. iii., 411. Kirch. Alg. Schles. 43. Eng.
Fl. v., 322. Gray AIT. i., 288. Hass. Alg. 71, t. 7.

Conferva torulosa, Dillw. Conf. p. 77, t. F.

Conferva fluviatilis nodosa fucum emulans, Dill. Muse. t. 7,
f. 48. '

Lemanea ftuviatilis, var. /3- torulosa, Eng. Bot. ii., t. 2423.
Harv. Mon. 119.

Conferva fluviatilis, var. 2. With. AIT. iv., 134.

In streams.

" From a little horny disc, fixed to the hard bodies which support it,
arise from six to thirty filaments, from one inch to 2^ inches in length,
curved in one direction. Their colour is of a brownish or reddish-green,
obscure or livid. They acquire in diameter the greatest dimensions of
all the Confervae." — Bory.

Bory states that " M. Thore, of Dax, first remarked, in the Conferva
fluviatilis of Linnaeus, a fact which is verified in the other species of our
genus. The recent filaments of this Lemnnea, presented towards the
flame of a candle, explode and extinguish the candle. This phenomenon
does not take place in dried specimens. It is owing to some gas shut
up in the connections of the joints, and which, put in expansion by the
heat, presses against the walls and breaks them with an explosion. A
remarkable movement of retraction is experienced in the fingers which
hold by the two extremities! the filament experimented upon. As to the
smell of the burnt plant, although very peculiar, it cannot be compared
to^that of animal substances submitted to the fire. I have not met with
any Lemania in stagnant waters ; they grow in quick waters. It is in
the pm-e fountains, large rivers, in very rapid rivulets, that they appear
to delight. Many, moreover, flourish especially in those places where
the current has the greatest force, such as in mill sluices, and the most
impetuous falls of cascades." — HassalVs Algtz, p. 70.

Plate CXXVIII, fiy. 2. Filaments natural size.

SUPPLEMENT,

To follow at page 4 —

Pleurococcus bituminosus . (Bory. Diet, in., 15.)

Thallus mucous, brown-black, or pitch -colour, cells small,
rounded angular, greenish brown, 4-8 associated in families,
tegument scarcely broad, colourless, hyaline, indistinctly lamel-
lose.

SIZE. Cells -002 mm. ; families Ofl-'02 mm.

Rabh. Alg. Eur. i., 28.

Chaos bituminosus, Bory. Diet, iii., 15.

Palmella bitwninosa, Meneg. Nost. p. 56.

Protococcus lituminosus, Kutz. Tab. Phyc. i., t. 5.

Gleocapsa bituminosa, Kutz. Spec. 224.

On walls of damp cellars, &c.
Plate CXXIX. Jig. 1. Cells and families x 400 diam.

Fleurococcus vestitus. Reinsch. Algen. Fl. p. 56.

Cells solitary, rarely united in small families, orange ; cell-
membrane thick, densely invested with small hairs.

SIZE. Cells -012--022 mm. diam.

Kabh. Alg. Eur. i., 29.

Acantlwcoc.cus vestitus, Lagerh. Svenska Vet. Akad. Forh.,
1883, p. 37.

Plate CXXIX. fig. 2. Cells X 400 diam.

GENUS 14 bis. DACTYLOCOCCUS. l\7ag. (1849).

Cells oblong or fusiform (at first ovate-cuspidate, then ellip-
soid), free swimming, 2-8 associated in families, at length
dividing and becoming single.

Propagation by division in one direction.

Dactylococcus De Baxyanus. Reinsch. Contrib. t. x., /. 1.

Cells broadly elliptical-oval, apex broadly rounded, base
attenuated into a hyaline pedicel, half as long as the cell, and
expanded at its extremity, single or twin, cell-contents intense
green, granulose, at length divided in 3 or 4. Cell membrane
thick.

SIZE. Cells -033 x '016 mm.

Parasitic on small aquatic crustaceans, Entomostraca, &c.

Plate CXXIX. fig. 3. a, individuals X 400 diam. ; b, two individuals
X 720 diam.

SUPPLEMENT. 297

To be inserted at page 91 —

Spirogyra velata. Nordst. Lund. Univ. Arsskrift, 1872, Vol. ix.
Sterile cells with the ends truncate, 3-4 times as long as

broad, chlorophyll band single, making 1^ to 2J tarns in the
spiral.

Spores elongated-oval, polymorphous, 1 J to 3 times as long
as broad ; epispore thick, composed of four membranes ; the
second is hyaline and scrobiculate ; the third is coloured
(Nordstedt).

Sporiferous cells a little swollen or not at all, sometimes
shorter, sometimes a little longer than the spores.

SIZE. Cells •035--04nim.; zygospore -06 x -035— -085 X
•045 mm.

Petit Spirogyra, p. 25, t. 7, fig. 1-5.

In ditches.

England (Leicester. F. Bates).

The zygospore has a broad hyaline border finely denticulate with the
scrobiculations of the second membrane.

Plate CXXX. Jig. 1. a, sterile cells X 200; b, sterile cell x 400;
<?, fertile cells with zygospores X 200 diam. ; d, e, f, zygospores with the
investing cells X 400 diam.

At page 165, after (E. capillare, add —

(Edogonium capilliforme. Kutz. Spec. 367 (?).

Oogonia single, a little swollen, obversely egg-shaped, open-
ing with a superior pore ; oospores ellipsoid-globose or cylin-
clrically globose (almost four-angled in optical section), not
filling the oogonia ; male plants a little more slender than the
females ; spermogonia 2-10 celled, alternating with the vegeta-
tive cells; terminal cell obtuse.

SIZE. Cells of female -03--034 mm., 1 J to 3 times as long ;
of male '024--02S mm., ]^ times as long ; oogonium -042--048
x •051--062 mm; oospore '037--045 x -04--05 mm., usually
•039--04; sperm, coll -02--025 x -008--01 mm.

Wittr. Mon. (Edog. p. 31. Kutz. Tab. Phyc. iii., t. 37, f.
8(7).

In pool and ditches.

Britain (Leicester. F. Bates).

Plate CXXIX, fig. 4. a, female filament with oogouia X 400 diam. j
fc, male cells with alternating spermogonia X 400 diam.

2 T

298 SUPPLEMENT.

Insert at page 187 —

Chroolepus unibiinum. Kutz.

Stratum thin, crnstaceous, rather pulverulent, reddish brown
growing pale when dead, threads and branches abbreviated,
torulose, joints nearly as long as broad, broadly elliptic or sub-
globose.

SIZE. Ce.ls -02 mm. diam.

Rabh. Alg. Eur. i., 372.

Protococcus crustaceus, Kutz. Spec. 203.

Protococcus umbrimts, Kutz. Pbyc. Gen., t. 7, f. 2. CoLn in
Hedwigia i., p. 1.

On the bark of beech and oak. (Kelvedon. E. G. V.)
Plate CXXX. fig. 2. Chroolepus umbrinum X 400 diam.

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GLOSSARY.

ACHROMATIC (a, Gr. without, -f chromos, colour).

Colourless.
ACICULAR (acus, L. a needle).

Needle -shaped.
ACUMINATE (acumen, L. a point).

Tapering to a point.
^ERUGINOUS (cemgo, L. rust of copper).

Of the colour of verdigris — blue green.
AGAMO-HYPNOSPORES (agamos, Gr. unmarried, -f hypnospores).

Neutrally formed resting spores.
AGAMOSPORE (agamos, Gr. unmarried, -f spore).

Spore formed neutrally without fecundation.
AGAMOSPOROUS (agamos, Gr. unmarried, -f spore).

Bearing spores without fecundation.
ALTERNATE (alternus, L. one after another).

Two organs so placed as not to be opposite to each other.
AMCEBOID (amoeba, -f eidos, resemblance).

Resembling an Amoeba.
AMORPHOUS (a, Gr. without, + morphos, form).

Without definite form.
AMYLACEOUS (amylon, Gr. flour).

Resembling starch.
ANASTOMOSE (anastomo, Gr. to furnish with a mouth, to bring

to a mouth).

The opening of one vessel into- another, applied to

threads or tubes which become confluent, and form an

irregular network.
ANDROGONIDIA (aner, Gr. a man, + gonidia).

Peculiar zoogonidia produced by female plants from

which male plants are developed.
ANDROSPORANGIUM (aner, Gr. a man, -f sporangium).

Sporangium enclosing spores of male plants, or andro-

spores.

308 GLOSSARY.

ANDROSPORE (aner, Gr. a man, + spora, a seed).

A special kind of zoo spores produced in cells, which

originate the dwarf males in (Edogonium.
ANTHERIDIA (anther, -f eidos, resemblance).

Certain reproductive organs supposed to be analogous to

anthers, or fecund ative.
APICULUS (diminutive of apex, L. a short point).

Ending with a short point.
ARCUATE (arcuo, L. I bend like a bow).

Bent like a bow.
AREOLA (areola, L. a little space).

An angular space with an elevated margin.
ARTICULATE (articulus, L. a joint).

Composed of joints.
BILOBATE (bis, L. twice, -f lobus, a lobe).

Having two lobes.
BINATE (binus, from bis, L. by couples).

In pairs.
BOTRYOID (botrys, Gr. a bunch of grapes).

Collected in clusters like a bunch of grapes.
BULLATE (bull a, L. a bubble).

Blistered or puckered.
C^SPITOSE (ccespes, L. a turf or sod).

Growing in tufts, after the manner of a turf strictly, with

many stems from one root.
CAPILLARY (capillus, L. a hair).

Thread-like, resembling a hair.
CARPOSPORE (carpos, a fruit, -f spora, a seed).

Spores produced (by conjugation) in a sporo-carpium.
CARTILAGINOUS (carti/ago, L. a tendon).

Hard and tough like cartilage.
CAULOID (caulus L. a stalk or stem).

Resembling, or analogous to, a stem.
CHLOROPHYLL (chloros, Gr. green, -f phyUon, a leaf).

The green colouring matter of leaves, and other green

parts of plants.
CHLOROPHYLLOSE (chloros, Gr. green, -f pliyllon, a leaf).

Resembling chlorophyll green.
CILIATE (cilium, L. an eyelash).

Furnished, or fringed, with hairs.
CILIUM, CILIA (cilhim, L. an eyelash).

Hair or bristle placed marginally.
CIRCINATE (circino, L. I turn round).

Curled round, like the young frond of ferns.
CIRCUMSCISSILE (circum, L. around, -f scindu, I cut).

Cut round transversely.
CLATHRATE (clathrus, L. a lattice).

Latticed, or perforated like a window.

GLOSSARY. 309

(coenobios, Gr. a community of living).

A community of a definite number of individuals united

in one body.
CONCENTRICALLY (concentricus, L. with a common centre).

In rings, with a common centre.
CORDATE (cor, L. the heart).

Heart-shaped.
CORIACEOUS (corium, L. leather).

Of a leathery consistence.
CORYMBOSE (corymbos, Gr. the top, a cluster of fruit or

flowers).

Resembling the inflorescence called a corymb.
CRENATE (crena, L. a notch or cleft).

Notched or scalloped.
CRUSTACEOUS (crusta, L. the hard surface of a body, the rind).

Hard and brittle, or forming a crust.
CUNEATE (cuneus, L. a wedge).

Shaped like a wedge.
CUSPIDATE (cuspidatus, L. pointed).

Tapering gradually to a sharp, stiff point.
CYTOBLAST (cytos, Gr. a cell, -f blastos, a germ).

A cell germ.
CYTODERM, CYTIODERM (cytos, Gr. a cell, -f- dermos, a membrane).

Cell membrane.
CYTOPLASMA, CYTIOPLASM (cytos, Gr. a cell, + plasma, formation).

Cell contents.
DECUSSATE (decussatus , L. cut crossways like the number X,

decem} .

In pairs, alternately crossing.
DEHISCENCE (dehisco, L. I gape).

Splitting into regular parts.
DIAPHANOUS (diet, Gr. through, -f phaino, I show).

Nearly transparent.
DICHOTOMOUS (dichotomos, Gr. divided in two).

Forked equally.
DIFFLUENT (diffluo, L. I flow).

Readily dissolving.
DICECIOUS, DIOICOUS (dis, Gr. twice, 4- oikos, a house).

When the male organs are borne on one plant and the

female on another.
DISSEPIMENT (dissepw, L. I separate).

A partition or division.
ENCYSTED (en, Gr. within, -f cystis, a bladder).

Enclosed in a cyst or bladder.
ENDOCHROME (endon, Gr. within, -f chromos, colour).

Cell contents. Colouring matter of cells.
ENDOPHYTAL (endon, Gr. within, 4. phi/ton t a plant).

Growing within plants.

310

GLOSSARY.

ENDOSMOSE (endon, Gr. within, -f osmos, impulsion).

The inward current established between fluids of different

densities when separated by a membrane.
ENDOSPORIUM, ENDOSPORE (endon, Gr. within, + spora, a spore).

The inner coating of a spore.
EPIGYNOUS (epi, Gr. upon, -f gyne, a female).

Seated upon the female organ.
EPIPHYTAL (epi, Gr. upon, -f- phyton, a plant).

Growing upon plants.
EPISPORE (epi, Gr. upon, + spora, a seed).

The outer integument of a spore.
EPIZOIC (epi, Gr. upon, + zoon, an animal).

Growing upon animals.
EXOSPORIUM, EXOSPORE (exo, Gr. outwards, + spora, a spore).

The outer membrane of the coat of a spore.
FASCICLE (fascicula, L. a little bundle).

A bundle.
FASCICULATE (fascicula, L. a little bundle).

In bundles from a common point.
FILAMENTOSE (filum, L. a thread).

Composed of threads. Thread-like.
FOLIACEOUS (folium, L. a leaf).

Resembling a leaf.
FURFURACEOUS (furfur, L. bran).

Mealy, or resembling meal.
GEMINATE (gemini, L. twins).

Produced in pairs.
GENUFLEXUOUS (genu, L. a knee, -\-flecto, I bend).

Bent angularly like a knee joint.
GONIDIA (gone, Gr. offspring, seed, + eidos, resemblance).

Propagative bodies of small size not produced directly or

indirectly by any act of fertilization.
GONOSPHERE (gonos, Gr. seed, + sphcera, a ball).

A ball-like agglomeration of spores.
GYNANDROSPOROUS (gyne, Gr. a woman, + aner, a man).

Bearing male and female spores.
HAMATE (hamus, L. a hook).

Hook-shaped, resembling a hook.
HETEROCYST (heteros, Gr. diverse, + cystos, a bladder).

Intercalated cells of a special character differing from

their neighbours.
HETEROGENOUS (heteros, Gr. another, + genos, race, family).

Unlike, or dissimilar in kind.
HEXAHEDRICAL (hex, Gr. six, + hedron, a side).

Having six sides.
HOMOGENOUS (homos, Gr. alike, + genos, race, family).

Of the same kind. Consisting of elements of a like nature.
HORMOGONE (hormos, Gr. a necklace, + gone, offspring).

Special reproductive bodies, composed of a chain of cells.

GLOSSARY. 311

HYALINE (hyalos, Gr. glass).

Transparent, resembling glass.
HYPNOSPORANGIUM, HYPNOSPORANGE (liypnos, Gr. sleep).

Sporangium enclosing hypnospores.
HYPNOSPORE (hypnos, Gr. sleep + spore).

Spores which repose some time before germinating =

" resting spores. "
HYPOGYNOUS (hypo, Gr. under, + gyne, a woman).

Seated beneath the female organ.
IDIO-ANDROSPOROUS (idios, Gr. proper, + androspores).

Neuter individuals, producingandrospores(in(2/£/o^o?im??i).
INTERCALATED (inter -c alar e, L. to insert in the calendar).

Interspersed, placed between others.
INTERCELLULAR (inter, L. between, + cellular).

Between the cells.
INTERSTITIAL (inter stitium, L. a space between).

Placed between.
ISOLATED (insula, L. an island, through the Italian isola).

Detached, placed by itself.
ISOSPORE (isos, Gr. equal, + spora, a seed).

Applied to spores which are all of one size, or kind, in

the same plant.
LACUNA (lacuna, L. a little hole).

A depression, cavity, or intercellular space.
LAMELLAE (lamella, L. thin plates of metal).

Thin plates or membranes parallel to each other.
LAMELLOSE (lamellce, L. thin plates of metalj.

Formed of layers or plates superimposed.
LUBRICOUS (lubricus, L. slippery).

Slippery.
LUNATE (luna, L. the moon).

Crescent-shaped.
MACRANDROUS (macros, Gr. large, long, -f- aner, a man).

Having elongated male plants.
MACROGONIDIA (macros, Gr. large, long, + gouidia).

Large gonidia.
MATRICAL (matrix, L. the womb).

Belonging to the matrix.
MESOPHYLLIC (mesos, Gr. middle, + j?%Z/o5, a leaf).

In the middle of a leaf or frond.
MESOSPORIUM, MESOSPORE (mesos, Gr. middle, + spora, a spore).

The middle membrane of the coat of a spore.
METAGENESIS (meta, Gr. after, + genesis, origin).

A kind of alternation of generations.
MICROGONIDIA (micros, Gr. small, + gonidia).

Small gonidia.
MICROPYLE (micros, Gr. small, + pyle, gate).

The aperture in the skin of a seed which was the

foramen in the ovule. A little scar.

312 GLOSSARY.

MOBILE (molrilis, L. movable).

Movable.
MONILIFORM, (monile, L. necklace, + forma, shape).

Necklace-shaped, contracted at regular intervals.
MONOICOUS, MONOZCIOUS, (monos, Gr. one, + oikos, a house).

With male and female organs on the same plant.
MULTICELLULAR (inultus, L. many, -f cellula, a little cell).

Composed of many cells.
MULTILOCULAR (inultus, L. many, + loculus, a little place).

Containing many cells or cavities.
MULTI-PARTITE (multus, L. many, + partite).

Divided into many parts.
NANANDROUS (nanos, Gr. a dwarf, + aner, a man).

Having short or dwarf male plants.
NODULOSE (nodulus, L. a little knot).

Knotted, or with swollen joints.
NUCLEUS (nucleus, L. a kernel).

The central germ around which a cell is formed. Small
spherical bodies contained within spores or other cells.
OBCORDATE (ob, L, inversely + cor, the heart).

Inversely heart-shaped.
OCTONATE (octo, Gr. eight).

Eight together.
OLEAGINOUS (oleaginus, L. of an olive tree).

Oily, or resembling oil.
OOGONIUM (pon, Gr. egg, + gonos, seed).

A kind of ovarian sac containing spores which, when
liberated, are called oospores.
OOSPORE (pon, Gr. an egg, + spora, a seed).

Spores produced in an ovarian sac.
OPERCULUM (pperculum, L. a cover or lid).

The lid or cover of a capsule.
PARENCHYMA (parenchyma, Gr. anything poured in beside).

Compressed or hexagonal cellular tissue.
PARENCHYMATOUS (parenchyma, Gr.).

Resembling the cellular tissue termed " parenchyma."
PARIETAL (paries, L. a wall).

Growing by, or to, the wall.
PARTHENOGENESIS (parthenos, Gr. virgin, _|_ genesis, origin).

Production of fertile seeds without sexual impregnation.
PARTHENOGONIDIA (parthenos, Gr, a virgin, + gonidia).

Gonidia produced without fecundation.
PATENT (pateo, L. I am open).

Spreading.
PECTINATE (pccten, L. a comb).

Pinnatifid, with narrow close segments, like the tooth of
a comb.

PEDICELLATE (pediculus, L. a little foot).
Having a foot, or stem.

GLOSSARY. 313

PENTAHEDRICAL (pente, Gr. five, + hedron, a side).

Having five sides.
PERICARPIUM (peri, Gr. around, 4. carpos, a fruit).

Covering or tegument of fruit.
PERIDERM, PERIDERMIC (peri, Gr. around, + derma, skin).

The enclosing membrane.
PERIPHERAL (peri, Gr. around, + pkero, to carry).

The outer portion of a circle.
PILIFEROUS (pilus, L. a hair, + fero, I bear).

Bearing hairs, hairy.
PLICATE (plica) L. a plait).

Folded, or plaited.
PLUMOSE (pluma, L. a feather).

Feathery, or like a feather.
POLYMORPHISM, POLYMORPHIC, (polus, Gr. many, _|_ morphos,

form).

Having many forms.
PRIMORDIAL (primordium, L. beginning).

Original, existing from the beginning.
PROTHALLUS (pro, Gr. before, -f thallus, a frond).

The false thallus first formed on germination of a

spore.
PSEUDO-BRANCHES (pseudos, Gr. false, -f branches).

False branches, or resembling branches.
PSEUDO-RAMOSE (pseiidos, Gr. false, -f ramus, a branch).

Having false branches.
PYRIFORM (pipus, L. a pear, 4. forma, form).

Pear-shaped.
QUADRI-RADIATE (quadrum, L. four-square, _|_ radiate).

With four radii, or rays.
QUATERNATE (quciter, L. four times).

Arranged in fours.
EAMULUS (diminutive of ramus, L. a branch).

A small, or secondary branch.
RENIFORM (renes, L. the kidneys, -[-forma, shape).

Kidney- shaped.
REPLICATE (re, L. back, + plico, I fold).

Folded back.
RESTING-SPORE. A spore which becomes quiescent, or rests for

a period, more or less long, before germination.
RHIZOID (rhiza, Gr. a root, + eitlos, resemblance.)

Resembling, or analogous to, a root.
ROSTRATE (rostrum, L. a beak).

Terminating with a beak.
SACCATE (saccus, L. a sac).

In the form of a bag.
SCALARIFORM (scala, L. a ladder, + forma, shape).

Barred or crossed like the steps of a ladder.

2 x

314 GLOSSARY.

SCROBICULATE (scrobiculus , L. a little ditch).

Marked with little pits or depressions.
SCUTATE (scutum, L. a shield).

Buckler-shaped.
SEGMENTATION (segmentum, L. a segment).

Dividing into segments.
SEGREGATE (segrego, L. I separate).

To separate from others, or set apart.
SEMI- (L. half).

Prefix signifying " half."
SEPTUM (septum, L. a hedge).

A partition or division.
SIGMOID (sigma, Gr. the letter S).

Shaped like the letter S.
SINUS (sinus, L. a hollow).

A depression or notch.
SPERMATOZOA, SPERMATOZOIDS (sperma, Gr. a seed, _f zoon, an

animal).

Thread-like bodies possessed of motion, supposed to

have fecundative power.
SPORANGIUM, SPORANGIA (spora, Gr. a seed, -f angos, a vessel).

A spore-case, having spores produced within it.
SPORIFEROUS (spora, Gr. a seed, -f. fero, I bearj.

Bearing spores.
SPOROCARPIUM (spora, Gr. a seed, -f carpos, a fruit).

Covering or capsule enclosing spores, or carpospores.
SPORODERM (spora, Gr. a seed, -f derma, a membrane.

The coating or covering of a spore.
SPORULES (diminutive of spore).

Minute spore-like bodies.
STRATOSE (stratum, L. a couch or bed).

Arranged in layers or strata.
STRATUM (L. a couch or bed).

A layer, or extended bed.
STRIJS (stria, L. a groove or furrow).

Parallel lines or shallow grooves.
SUB- (L. under).

A common prefix indicating " almost " or '- nearly."
SUBULATE (subula, L. an awl).

Shaped like an awl.
TANGENTIAL (tangens, L. touching).

In the direction of a tangent. Touching a straight line

on the arc of a circle.
TEGUMENT (tego, L. I cover).

A covering or membrane.
TERETE (teres, L. long, round, and tapering).

Cylindrical, tapering like the trunk of a tree.
TETRAHEDRICAL (tetra, Gr. four, -f. hedron, a side).

Having four sides.

GLOSSARY. 315

TETRASPORES (tetra, Gr. four, + spores).

Certain spores produced in fours.
THALLUS (thalhs, Gr. a frond).

An expansion somewhat resembling a leaf.
TORULOSE (toritlus, L. a little cord).

Almost synonymous with moniliform.
TRICHOGONIA (thrix, Gr. the hair, + gonos, generation).

The female reproductive organs in Batrachospernis.
TRICHOME (thrix, Gr. the hair).

The thread or filament of filamentous algee.
TRICHOTOMOUS (fricha, Gr. threefold, + temno, I cut).

Dividing in threes.
TRUNCATE (truncus, L. a stump).

Terminating very abruptly.
TUBERCULATE (tuberculum, L. a pimple).

Covered with warts or tubercles.
UNICELLULAR (units, L. one, + cella, a cellar).

Literally, composed of one cell.
VACUOLE (racuus, L. empty).

Drops which are seen in the interior of the protoplasm

of cells.
VAGINA, VAGINATE (vagina, L. a sheath).

A sheath, sheathing.
VERRUCOSE (verruca, L. a wart).

Covered with warts.
VERTICILLATE (verticillus, L. a whorl).

Arranged in whorls.
VESICLE (vesicula, L. a little bladder).

A bladder-like cavity. .
VIBRATILE (vibro, L. to quiver or shake).

That moves to and fro, or vibrates.
ZOOGONIDIA (zcon, Gr. animal, + gonidia, which see).

Gonidia endowed with active motion.

ZOOSPORANGIUM, ZoosFORANGE (zoon, Gr., an animal, + sporan-
gium) .

Sporangium enclosing zoospores.
ZOOSPORES (zod'n, Gr. an animal, -f spora, a spore).

Locomotive spores.
ZYGOSPORE (zygos, Gr. a yoke, marriage, + spora).

A spore resulting from conjugation-

316

INDEX,

PAGE.

AGARDHIA.

ccerulescens. Gray . . 107

AiNAcxrs.

calcaren. Kntz. . . . 279

AMPHICOMUM.

aureum. Johnst .... 185

Anabaena. Bory 234

circinalis. Phil 237

circinalis. Rabh. . . . 235

fos-aquce. Hass. . . . 236

fios-aquce, Rabh. . . . 227

flos-aquse. Kutz. . . . 235

granularis. Kntz. . . 231

Hassallii. N. <£• Witt. . 236

impalpebralis. Hass. . 244

ingequalis. Br. . . . 239

intricata. Kutz. . . . 227

lickeniformis. Hass. . . 236

oscillarioides. Bory. . . 238

Ralfsii. (Kutz.) . . . .237

Smithii. N. $• Witt. . . 237

spiralis. Thomp. . . 235

Thwaitesii. (Rolfs.). . . 238

variabilis. Kutz. . . . 236

ANACYSTIS.

marginata. Men. . . . 212

ANKISTRODESMUS.

acutissimus. Ar. ... 19
falcatus. Ralfs. ... 19
gregarius. Breb. ... 19

Aphanizomenon. Mot: . 239

flos-aquas. Ralfs. . . . 240

incwrvum. Mor. . . . 240

Aphanocapsa. Nag. . . . 210

clepressa. Rabk. . . .211

Grevillei. Rabk. . . .210

parietina. Nag1. . . . 210

rivularis. Rabk. . . . 210

virescens. Rabk. . . . 210

Aphanochaete. Br. . . . 197

hystrix. Rabh. . . . 197

repens. Br. . . . .197

Aphanothece. Nag. . . .218

Mooreana. Lager. . . . 218

prasina. Br 218

Stagnina. Italh. , 219

PAGE

. 17
. 18

Apiocystis. Nag. ..
Bratiuiana. Nag. ..
AETHRONBMA.

cirrkosnm. Hass. . .
ARTHROSIPHON.

alatus. Rabh

Grevillei. Kntz. . .
ARTHROSPIRA.

Jenneri. Hedw. . .
Bangia. Lyngb

atro-pnrpnrea. Ag. .

calopkylla. Carm. . .
Batxachospexmum. Bory

alpestre. Hass. . .

atrnm. Harv

bambnsimim. Bory.

Boltoni. Cke

cenfusum. Hass. . .

conglomeration. Vauch.

deter sum. E. Bot. . .

Dillenii. Bory. . .

fasciculatum. Vaucb.

giganteum. Kutz. .

lielmintosinn. Hass. .

kispidum. D.C. . .

leeratophyta. Bory.

ludibunda. Bory. .

moniliforme. Roth.

myosurus. Duel. .

proliferum. Hass.

pulclierrlmum. Hass.

rubrum. Hass. .

setigerum. Rabh. .

stagnale. Hass. .

suevorum. Kutz. .

turfosa. Bory. .

vagum. Ag. ..
BELONIA.

torulosa. Carm. .

BOTKYDIACE^S

Eotrydina ...... 14

Gfrevillei. Men. . . ,211
vulgaris. Breb. ... H
Botxydium. Wallr. . . .111
argillaceum, Grev. .. . 114
grauulatum. Linn.

270

267
267

245
282
282
130
286
290
292
291
290
289
191
292
. .293
. 195
. . 289
. . 293
. .291
. . 292
288, 290
. . 288
.. 25
. . 289
. 288
. . 285
. . 288
. . 290
. . 292
. .291
.. 291

. . 240

Ill

INDEX.

317

Botryococcus. K. . .

Brannii. Kutz. . .
Bulbochaete. Ag. . .

Brebissonii. Kutz. .

gigantea. Pr. . . .

gracilis. Prings.

insignis. Prings.

intermedia. D.Bij. .

mirabilis. Witt?'. . .

polyanclra. Cleve. .

Pringslieimiana. Ar. .

pygmasa. Witt?: . .

rectangularis. Witti: .

Ituthii. Gray. . . .

setigera. Ay. . . .
BYSSUS.

aurea. E. Bot.

botryoides. Hucls.

botryoides virens. Ray.

flos-aquce. Linri.

iolithus. Liun. . .

nigra. E. Bot. . .

pulverulenta . Dillen.
Calothrix. Ag

atrovirens. Harv. . .

Brebissonii. Kutz. .

Dillwyni. Hass. . . .

distorta. Harv. .

interrupta. Carm. . .

lucifuga. Carm. .

mirabilis. At

PAGE
. 17

. 17
. 173
. 175
. 175
. 177
. 176
. 174
. 176
. 174
. 177
. 176
. 177
. 175
. 175

. 185
. 211
. 211
. 240
. 116
. 187
. 211
. 275
. 263
. 203
. 276
. 270
. 266
. 262
. 263
. 276
. 277
. 275

. 185
. 138
. 140
. 139
. 138
. 139
. 188
193

Orsiniana. Thur.
Smitiiii. Berk.

CALOTRICHE.E

CERAMIUM.

aureum. Hook. . . .

Chaetomorpha. Kutz.

implexa. Katz. . . .
linum. Kutz.
litorea. Harv. . . .
sutoria. Berk. . . .

CH.ETOPHOKACE/E. . . .

Chaetophora. Schr. . .

elegans. A(j

elegans. Lyngb. . . .194
endivasfolia. Ag. . . .194
fastigiata. Rail's. . , .191

pisiformis. Ag 193

punctiformis. Kutz. 195, 278
tuberculosa. Ag. . . . 194

ClIANTRANSIACE,E L'^5

Chantransia. Fr 283

chalybea. Kutz. . . . 284
compacta. Italfs. . . . 286
Hermanni. Kutz. . . . 284
investiens. Kutz. . . . 285

pygmsea. Kutz 285

scotica. Kutz 285

violacea. Kutz. . 283

CHARACIE/E
Characium. Br

ambiguum. Rabh. .

ornithocephalum. Br.

Sieboldi. Br

tenue. Herm
Chlamydococcus. Br. .

nivalis. Br

plnvialis. Br
Chlamydomonas. Ehr. .

pulvisculus. £hr. .
Chlorochytrium. Colin.

Lemnee. Colin
Chlorococcum. Fr. ..

frustulosum. Rabh. .

gigas. Grim

humicolum. JVag. ..

muroruin. Rabh. ..

vulgar e. Grev. ...
CHLOROPHYLLOPHYCE^.
CHLOROSPH^ERA.

Oliveri. Henf
CHOASPES.

serflentina. Gray ..
CHUOOCOCCACE.E. ...
Chzoococcus. Nay. . .

cohasrens. Nd(/. . .

turgid as. Nag. ...
CHROOLEPIM;
Chzoolepus. A(j

abietinum. Kabh. . .

Arnotti. Harv

aureus. Linn

ebenea. Harv

ilicicolus. E. Bot. . .

iolithus. Linn

lichenicolus. Ag. .

melaenus. Carm. . .

mesomelas. Carm. . .

odoratus. Lyngb. . .

umbrinus. Kutz. . .
CHTHONOBLASTUS.

angutformis. Kutz. .

Lyngbyei. Kutz. . .

repens. Kutz

salinus. Kutz
CHYTKIDIE.K
Chytridium. Br

acuminatnm. Br. . .

ampullaceum. Br. . .

anemones. D. By. . .

Barkerianum. Ar. .
Cladophora. Kutz

canal icularis. Kutz. .

crisjtata. Hass

crispatu Kutz

flavesceus. Ag

flavida. Kutz

frncta. Kutz. . .

PAGE

47
47

. 48

. 48

48

48

. 50
54
51

. 55

. 56

. 202

202

. 30

. 30

31

. 30
. 30
. 4
. 1

. 97

. 203

. 203

. 204

. 204

184

184

. 1&7

187

185

187

.186

186

. 187

. 187

.187

.180

. 297

. 255
. 255

255
193
198
199
200
201
199
141
144
14:i
143
144
144
142

318

INDEX.

CLADOPHORA — (continued)

glomerata. Linn. .

segagropila. Kutz. .
Clathrocystis. Nenf. .

au'iiginosa. Henf.

roseo-ptrsicina. Cohn.
CLOSTERIUM.

falcati/m. Men. . .

Griffithii. B. . • .
CLUZELLA.

myosurus. Bory. . .
COCCOCHLORIS

cystifera. Hass. . . ,

depressa. Men. .

Grevittei. Hass. . . .

hyalina. Hass.

Ivjalina. Men.

Mooreana. Hass.

quaternata. Breb. .

radicata. Johns t.

rii-ularis. Hass.

staff nina. Spr. .

stagnina. West . .
COCCOPHYCE.E. : ; .
Cod.iolum.5r. . .

gregariurn. Br. .
Ccelastrum. Nag. . .

cambricum. A?'.

microsporum. JSr. .

Naegelli. Rabh.

sphsericum. Nag.
Ccelosphaerium. Nag.

Kutziugianum. Nag. ,
CCENOCOLEUS.

cirrhosus. Berk.

Smitliii. Berk. .
Coleochaete. Breb.

orbicularis. Prings.

scutata. Breb.

soluta. Prings. . .
Conferva. L. ...

cegagvopila. Linn. .

cegagropilaris. Gray

alpina. Eng. Fl.

amphibia. Dillw.

amphibia. Ray .

annulina. Roth.

arenicola. Berk.

atra. Dillw. . . .

atropnrpurea. Dillw.

aurea. Dillw. . .

Hcolor. E. Bot. . .

bipunctata. Dillw. .

bipunctata. Eng. Bot.

bombycina, Ag.

bombt/cina. Kutz.

Brownii. Dillw.

canalicularis. Sibth.

capillftris. Huds. . ,

chalybea. Dillw. . ,

PAGE

. 140

, . 145

. 212

. 212

6,213

. 19
. 19

. 25

. 218
. 211
. 211
11, 219
. 11
. 12
. 207
. 211
. 210
. 219
. 218

. 49
. 49
. 45
. 40
. 46
. 45
. 45
. 213
. 213

. 276

. 277
. 195
. 197
. 196
. 196
. 136
. 145
. 145
. 98
. 123
. 122
. 134
. 141
. 292
. 283
. 185
. 181
. 79
. 77
. 137
. 135
. 145
. 144
. 139
284

CONFERVA — (continued) PAGE

ccerulescetis. Eng. Bot. . 107
corynibosa. E. Bot. . . 284
crassa. Engl Fl. ... 139
crispata. Dillw. . . . 143
cynnea. Eng. Bot. . . . 266
Dama?-cornu. Ray . . .195
deeort'icans. Dillw. . . 260
decifssata. Dillw. ... 77
dichotoma. Dillen . . . 120
distorta. Dillw. . . . 268, 270

ebenca. Dillw 187

ecTiinata, E. Bot. . 195. 278
ecMnulata. Gray . . . 278
ericetoruni. Harv. ... 98

exigna. Dillw 189

flavescens. Dillw. . . .144

floccosa. Ag 136

flwiatiUs. Dillw. . . .294
fontana nodosa. Dill. 290, 293
fontana, nodosa. Ray . . 288
f ontinalis. Berk. . . . 1 37
fontli,alls. Dillw. . . . 252
fontinalis. Ray .... 143
fracta. Eng. Fl. ... 142

frigida. Dillw 122

fugacissima. Dill. . . .136
ft/gacissima. Grev. . . 135
gelatinosa. Dillw. . . . 288
gennflexa. Dillw. . . . 105
globosa. Phil. Trans. . . 145
glomerata. Linn. . . . 143
ilicicola. E. Bot. . . .186
implexa. Dillw. . . .140
inflate. Eng. Bot. ... 90
jugalis. Dillw. ... 90, 86
liclienicola. E. Bot . . . 187
limosa. Fl. Dan. . . . 251

linum. Ag 139

linum. Harv 138

litorea. Harv 138

lubrica. Dillw. . . 180, 189
hilrica. Eng. Bot. . . .193

lubrica. Koth 16

lucens. E. Bot 180

marina triclwdes. Eay . ,142
melaena. Lyngb. . . . 187
mirabilis. Dillw. . . . 263

tnuralis. Dillw 183

nnttabilis. Dillw. . . . 191
myochrous. Dillw. . . . 265
nana. Dillw. . . . 190, 284

nitidum. Dillw 87

ocellata. Dillw 271

ochracea. Dillw. . . : 258
odorata. Lyngb. . . .186
pinnatula. Dillw. . . . 144

Plinii. Ray 120

protensa. Dillw. . . . 190
pnrpurasccns. Carm. . . 99

INDEX.

319

CONFE RVA — {continued)

reticulata. Dill. .

sordida. Dillw. .

splralis. Dillw. .

stlctica. Eng. Bot.

sutoria. Berk. . ,

sutoria. Crouan .

tenerrima. Kutz .

terrestris. Ray .

torulosa. Dillw. .

undulata. Breb. .

vagabunda. Huds.

vaginata. Dillw.

vaginata. E. Bot.

vesicata. Dillw. . ,

vesicata. Lyngb.

vivipara. Dillw. .

vulgar is. Kirsch.

zonata. W. & M.
CONFEKVACE.E. . . ,
CONJUGATA.

condensata. Vauch.

cruciata. Vauch.

decimina. Gray.

gracilis. Vauch.

inflata. Gray.

inflata. Vauch. . ,

long ata. Vauch.

pectinata. Vauch. .

porticalis. Vaach. .

princeps. Vauch.

quinina. Gray. . .

stellina. Vauch. ,

COSMOCLADIUM.

saxonicum. D.By. .

Cylindiocapsa. Rein.
involuta. Rein.
nuda. Rein.

PAGE
. 38
. 138
. 90
. 97
. 139
. 140
. 137
. 123
. 295
. 160
. 142
. 276
. 256
. 124
. 172
. 175
. 135
. 180
135

Cylindrospermum. Rolfs.

catenatum. Rolfs. .

elongatum, Kutz.

leptospermum. Kutz. .

licJieniforme. Kutz.

macrospermum. Kutz.

Ralfsii. Kutz. . . ,
CYMATONEMA.

confer I'aceum. Kutz. .

CYSTIPHOR^E

CYSTOCOCCUS.

humicola. Nag. . . .

. 91

. 79
. 90
. 80
. 90
. 97
. 92
. 77
. 89
. 86
. 90
. 80

. 21

. 22
. 22
. 23

. 243
. 244
. 243
. 243
. 242
. 243
. 237

Dactylococcus. . .

De Baryanus. Rein.
DASYACTIS.

plana. Kutz.

Dasygloia. Thw. . .

amorpha. Thw. . .
DEMATIUM.

turfaceum. Link.
DESMIDIE.E

160
203

30

296
296

281

274
274

273

74

PAGE

DESMONEMA. B.

Dillwyni. Berk. . . . 276

Dictyosphaerium. Nag. . 20
coustrictum. Ar. ... 21
Ehreubergianuin. Nag. • 20
reniforme. Buln. ... 21

Dimorphococcus. /;/•. . . 27
luuatus. Br ..... 27

DIPLOCOLON.

Heppii. Hzig ..... 233

DOLICHOSPERMUM.

inesquale. Ralfs .... "239
Ralfsii. Ann. N. H. . . 237
Smithii. Thw ..... 237
Thompsoni. Ann. N. H. . 236
Thwaitesii. Ralfs. . . . 238

DOTHIDEA.

anemones. B.C. . . . 201

Draparnaldia. A</. . . . 191

condensata. Hass. . . . 190

cruciata. Hicks. . .192
elongata. Hass. . . . 189

glomerata. Ag ..... 191

iiana. Hass ...... 190

pluniosa. VaucJi. . . . 193

sparsa. Hass ..... 190

tennis. Eng. Fl. ... 189

DRILOSIPHON.

muscicola. Kutz. . . . 266

ECHINELLA.

articulata. E. Bot. . . 195

ECTOCARPUS.

aureus. Lyngb ..... 186
chalybeits. Gray. . . . 284

ECTOSPERMA.

geminata. Vauch. . . . 125

hamata. Vauch. . . . 126

ovoidea. Huds ..... 125

terrestris. Vauch. . . . 126
ELISA.

distorta. Gray

inirabilis. Gray. .
Snteroniorpha. Link.

intestinalis. Linn.

lacustris. Hass. .
Eremosphaera. D.By.

viridis. D.tiy
Eudorina. Ehr

elegans. Ehr

FlSTULARIA.

intestinalis. Grev.
FLOIUDE.I:

GlRABDTA.

fusco-purpurea. Gray.
Glseocapsa. Kufz. .

aeruguosa. Kutz.
aniijla. Kulz
arenaria. Rubk.
atrata. RabJi

270
263
130
130
131
3
3

65
67

131

282

283
204

207
7

207
205

320

INDEX.

GL.EOCAPSA — (continued?)

botryoides. Kutz.

caldariorum. Rabli.

coracina. Kutz.

livida. Kutz. . .

magma. Kutz. .

ParoUniana. Men.

polydermatica. Kutz. .

qnaternata. Kutz. .

Kalfsiaua. Kutz. . ,

rupestris. Kutz. . .

rupicola. Kutz. .

sanguinea. Kutz.

Shuttleworthiana. Kutz.
Glaeocystis.

adnata. Nag. . . •

ampla. Kutz. . . .

botryoides. Kutz. . .

Paroliniana. Men. . .

rupestris. Rabh. . .

vesiculosa. Nag. . .
Glaeothece. Nag. . . .

cystifera. Rabh.

devia. 'Nag

granosa. Rabli. .
Gloiotrichia. Ag. . . .

angnlosa. Ag. . . .

Boryatia. Kutz.

gigantea. Rabb.

natans. Tliur. . • .

pisum. Thur.
Gomphosphaeria. Kiit~.

aponina. Kutz. . . .
Gonatonema

notabile. Wittr.

GONATONEME-E ....

Gonium. Mull

glaucum. Ehr. . .
pectorale. Midi.

H-EMATOCOCCUS.

cernginosus. Hass. .
Allmanni. Hass. . .
arenarius. Hass.
binalls. Hass.

Cor da. Men

cryptophila. Hass. . .
frustulosus. Hass. .
granosus. Hass. .
Hookerianus. B. & H. .
insignis. Hass. .
lividus. Hass.
mucosus. Mori*. .
murorum. Hass.

. nivalis. Ag

pluvialis. Flot. . . .
rupestris. Hass. .
sanguineus. Ag. .
sanguineus. Harv. .
theriacus. Hass. . .
vulgaris. Hass. . . .

PAGE
. 8
. 206
. 205
. 205
. 207
. 8
. 206
. 206
. 200
. 209
. 208
. 208
209

. 8
. 6

. 8
. 8
. 7
. 7
. 217
. 217
. 218
. 218
. 281
. 281
. 281
. 281
. 281
. 282
. 213
. 213
. 108
. 110
. 107
. 69
. 214
70

. 207
. 10
. 207
. 204
. 51
. 10
. 30
. 218
9

. 9
. 205
. 51
. 30
. 51
. 51
7, 206
. 209
. 10
. 4
. 4

Hapalosiphon. Nay. . .

byssoideus. Kirch. . .
HASSALLTA.

byssoidea. Hass. . .

compacta. Hass.

ocellata. Hass. . . .

turfosa. Hass. . . .
Homalococcus. Kutz.

Hassallii. Kutz. . .

HOEMIDIUM.

murale. Kutz. . . .

parietinum. Kutz. . .
Hormiscia. Ares. . . .

sequalis. (Kutz.)

bicolor (E. B.} . . .

moniliformis. (Kutz.) .

speciosa ( Carm.) . .

zonata. W. & M. . .
HORMOSIPHON.

ellipsosporum. Desra. .

inundation. Katz. . .

macrosporus. Kutz. .

natans. Kutz.

stagnalis, Kutz. . .
Hormospora. Breb. . .

mutabilis. Breb.

ramosa. Thm. . . .

trans versalis. Breb.
HUJTIDA.

cyanea. Gray. . . .

decortlcans. Gray .

murdlis. Gray .
Hydxianum. Rabli. . .

beteromorphum. Rein.
HYDROCOLEUM.

therm ale. Kutz. . .

tinctorium. Br. . .

HYDRODICTYE.E

Hydrodictyon. Roth. .

utriculatnm. Roth.
Hydxuxus. Ag

Ducluzelii. Ag.

fcetidus. Vaucb. . .

penicellatus. Ag. . .
HYDROGASTRUM.

granulatum. Eabh.
Inac tis. Kutz

Cresswelli. Thur. .

tinctoria. Thur. . . .
INODERMA.

lamellosum. Kutz. . .
Isactis. Thur. ....

plana. Thur

LEDA.

capucina. Bory. . .
Lemanea. Bory. . . .
corallina. Bory.

Dillenii. Bory. . . .

fluviatilis. Ag. . . .

PAGE

. 274

. 274

. 274
. 272
. 271
. 273

. 219
. 219

. 182
. 183
. 178
. 180
. 181
. 179
. 181
. 179

. 230
. 229
. 233
. 229
. 229
. 21
. 21
. 22
22

266

260

183

48

49

255
257
35
35
38
24
25
25
25

114
256
256
257

18

280
281

107
294
294
293
294

INDEX.

321

LEMANEA — (continued)
setacea. Bory. . .
torulosa. Ag.

LEMANEACK.E .....

LEPTOTHRIX.

ochracea. Kufcz.

LlCHENOIDES.

fungiforme. Kay. .

LlMNACTIS.

dura. Kutz. . . .

LlMNOCHLIDE.

flos-aquce. Kutz.

LlNKIA.

dura. Grev. . .

LlTHONEMA.

calcarea. Hass. .

crustaceum. Hass. .

Lyngbya. Ag. . . .

ceruginosa. Ag. . .

sestuarii. Lieb. . .

PAGE

. 292

. 295
. 294

. 258
114

279

corum.

crispa. Jenner . .

cnrvata. Eabh. . .

floccosa. Hass.

innndata. (Kutz.) .

littoralis. Carm.

majuscula. Cocks .

muralis. Ag. . .

ochracea. Thur.

papyrina. Kirch.

rupestris. Ay. . .

sj)eciosa. Carm.

subfusca. (Ag.)

turfosa. (Carm.)

vulgaris. Kutz. .

zouata. Hass. . .
MASTIGONEMA.

plana. Rabh. . .
•MERETTIA.

alpicola. Gray . .

nmcosa. Trev. . .
XVXerismopedia. Meyen.

glauca. Nag. . .

Goodseri. Hus. . .

punctata. Mey. . .

renis. Rabli. . ,

ventricali. Hob. .

violacea. Kutz. . .
MESOCARPE.E .....
XVXesocarpus. Hass. .

angustus. Hass.

depressus. Hass.

intricatus. Hass.

notabilis. Hass.

nummuloides. Hass.

ovalis. Hass.

parvulus. Hass.

plenrocarpus. D.By.

recurvus. Hass.

scalaris. Hass. . .

. . 240
279, 282

279

280
257
258
258
261
181
258
136
259
258
258
182
258
260
260
181
262
261
259
179

. 281

208
11
214
214
215
214
215
215
214
101
103
104
103
104
110
103
103
104
105
105
104

MlCRALOA.

protogenita. Bias. .

MlCRASTERIAS.

falcata. Corda. . .
XVIicrocoleus. Dcsm. .

anffuiformis. Hass,

chthonoplastes. Thur.

Dillwyni. Harv.

gracilis. Hass. .

marinus. Harv. . .

repens. Hass. . .

terrestris. Desm.
Micro cystis. Kntz. .

adnata. Men. . .

fsruginosa. Kutz. .

angulosa. Kutz.

atra. Kutz. . . .

atrovirens. Men.

livida. Men. . . .

marginata. Kirch. .

Paroliniana. Men. .

protogenita. Rabh.

rupestris. Men. .
Microspora. Thur. .

bombycina. Thur. .

floccosa. Thur. . .

fugacissima. Ag. .

glomerata. Hass.

vulgaris. Rabh. , .
MiLcrothamnion. Nag.

vexator. Cke. . .
Mischococcus. Nay..

confervicola. Nag. .
MONAS.

2Jrodiffiosa. Ehr.

MONORMIA.

intricata. Berk. . .

MONOTREMA.

bullosum. Thur. . .

IVIonostroma. Tlmr. . .

laceratum. Thur. .

Wittrockii. Born. . .

lylougeotia. D.By. . .

casrulescens. Eng. Fl. .

compressa. Eng. Fl. .

yenuflexa. Ag. . . .

yltttinosa. Hass. . .

glyptosperma. D.By. .

Isevis. Archer. . .

notabilis. Hass. . . .

quadranr/nlatus. Hass.

splendens. Kutz.
MYBIODACTYLON.

endirasfolium. Gray. .

NEIIATOGEN.E

NEMATOPHYCE/E

Nephrocytium. Nag. .

Agardhiannm. Nag. .

Naegelii. Grun. . .

136

PAGE
. 212

. 19
. 254
. 255
. 254
. 276
. 255
. 255
. 256
, 256
, 211
, 8
, 212
4

205
205
205
212
8

212
206
135
135
136
135
143
135
188
188
28
28

12
227

, 16
131
131
132
99
107
105
105
107
100
100
110
106
104

195

220

127

25

26

26

322

INDEX.

Nodularia. Mert. . . .

fiuviatilis. Grev. . .

Harveyana. Thur. . .

litorea. TJiur. . . .

Nostoc. Vauch. . . .

agglutinans. Kutz. . .

arc-turn. Kutz. . . .

carneum. Ag.

coniflonum. B. & Th. .

cocci/melon. Kutz. .

ccerulescens. Rabh.

coernleum. Lyngl). .

commune. Vaucli. . .

confusum. Ag. . . .

ellipsospornm. Rabh, .

flos-aqnce. Lyngb. . .

foliacenm. Ag. . . .

f/ranulare. Rabh. . .

htiruifusum. Carm.

iclithyon. Rabh.

intricatum. Men. . .

inundatum. Kutz. . .

ir regular e. Warton. .

Itzigsohnii. Rabh. . .

lacustre. Kutz. . . .

Linckia. B. $ Th. . .

littorale. Kutz. . . .

macrosporum. Men. .

micrjscopicum. Carm.

muscorum. Ag. . . .

nivale. Kntz.

sphaericnm. Vaucli. .

parietinum. Rabh.

peloponnesiacum. Kutz.

piscinale. Kutz. . .

piscinale. N. & Witt.

prismaticum. Ces. .

prunifornie. Ag. . .

purpurascens. Kntz. .

pyrenaicum. Rip.

rufescens. Ag.

rugosum. Kutz. . .

rnpestre. Kutz. * . .

salurn. Kutz. . . .

sphcsricum. Men. . .

spongiasforme. Ag. . .

tepidariorum. Br.

variegatum. Haw. .

verrncosum. Vaucli.

vesicarium. Men.

NOSTOC E.E.

NOSTOCHINE^

PAGE
. 244
. 295
. 245
. 244
. 224
. 228
. 231
. 229
. 231
. 233
. 233
. 233
. 231
. 227
. 230
. 235
. 231
. 231
. 230
. 233
. 228
. 229
. 234
. 233
. 228
. 227
. 231

232
230
234
231
231
234
228
228
231
233
229
233
229
231
232

231
234
229
231
229
234
232
224

hystrix. Thw 197

CEOOGONIACE/E 148

(Edogonium. . . . • . 148

acrosporum. D.By. . . 163

apopJiysatum. Br. . . . 162

apophysatum. Pr. . . .163

CEDOGONIUM: — (continued) PAGE
Archerianum. Cke. . .157
Areschougii. Wittr. . .159
Borisianum. L.Cl. . . . 162

Boscii. L.Cl 167

Braunii. Kutz. . . . 161
calcareum. Cleve. . . . 165
capillaceum. Kutz. . . . 170
capillare. (Linn.). . . . 165
capilliforme. Kutz. . . 298
carbonicum. Wittr. . . 166
cardiacum. Hass. . . .166
ciliatum. (Hass.). . . 163
Cleveanum. Wittr. . . 164
compressum. Rabh. . . 165
concatenatnm. (Hass.). . 163
crassiusculum. Wittr. . 162
crassnm. (Hass.). . . .173
crispnm. (Hass.). . . . 155
cryptoporum. Wittr. . .153

curvum. Pr 154

cymatosporum. W. $ N. 154
delicatulum. Kutz. . .169
depressum. Prings. . . 160
diplandrum. Jur. . . . 159
echinospermntn. Br. . . 164
ecJiAnospermum. Pr. . .164
excisum. Wittr. . . .157
fasciatum. Kutz. . . . 170
flavescens. Hass. . . .160
gemelliparum. Hass. . . 168
gemelliparnm. Pr. . . .168
giganteum. Kutz . . . .172

grande. Kutz 172

hexagonum. Kutz. . . .170
Hutchinsias. Wittr. . . 171
Itzigsohnii. D.By. . . 156
lacustre. Rabh. . . .172
Landsboronghii. (Hass.). 168
Londinense. Wittr. . . 170
longatum. Kutz. . . . 171
niacrandum. Wittr. . .161

minus. Wittr 154

Nordstedtii. Wittr. . . 157
paludosum. (Hass.). . .156
Petri. Wittr. . . ; .153
piUferum. Auers. . . .164
platygynum. Wittr. . .158

plnviale. Nord 159

princeps. Hass 171

Pringslieimianuin. Ar. . 158
Pringsheimii. Cram. . .166
pulcliellum. Br. . . .155
pulcliellum. Rabh. . .166
punctato-striatum. D.By. 167
„ var. minor. . 154

regular e. Vaup 165

Reinschii. Roy 160

rivulare. L. Cl 169

rivulare. Rabh. 168

INDEX.

323

CEcOGONiUM — (continued) PAGE
rostelhdum. Br. . . .155
Rothii. L. Cl. 158

setigerum. Vanp.
subsetaceum. Kutz.
tenellum. Kutz.
tumidulum. Kutz.
tumidulum. Pr.
nndulatum. Breb.
urbicum. Wittr.

162
173

169
168
156
160
15G

Vaucberii. L. Cl. 155

VaucJierii. Rabh.
vernale. (Hass.) .
vesicatum. Lyngb.
OLIVIA.

botryoides. Gray.

156
155
172

211

violacea. Gray 186

Olpidium. Br 200

ampullaceum. Rabh. . . 200
endogenum. Br. . . . 200

Oocystis. Nag 26

gigas. Ar 26

setigera. Ar 27

OPHIOCYTIE^E 38

Ophiocytium. Nag. ... 38

arbuscula. Br 39

cochleare. Br 38

Oscillaria. Bosc 246

aerugescens. Drum. . . 248

alata. Grev 267

antliaria, Jurg 250

autumnalis. Carm. . . 259
Bangii. Carm. .... 263

chalybea. Hert 253

chthonoplastes. E. Fl. 255, 256
contexta. Carm. . . . 249

corium. Hass 261

decorticans. Grev. . . . 260

Dickiei. Hass 254

Friesii. Harv 263

Frolichii. Kutz 253

insignis. Tlmv 253

irrigua. Kutz 251

leptotricha. Kutz. . . . 247

limosa. Ag 251

limosa. Hook 249

littoralis. Carm. . . . 258

lucifuga. Hass 2(J2

mucosa. Hass 253

muralis. Grev 183

muscorum. Carm. . . . 250

nigra. Vauch 252

nigro-viridis. Tim. . . 252

ochracea. Grev 259

papyrina. Bory. . . . 260
parietina. Vauch. . . . 250
rubiginosa. Carm. . . . 248

rttpcstris. Ag 260

sjjadicea. Carm 260

spiralis. Carm 247

OSCILLARIA — (continued)
splendida, Grev.

subfusca. Vauch. .

subuliformis. Thm.

tenerrima. Kutz.

tennis. Ag.

thermalis. Hass.

turfosa. Carm.

violacea. Johnst.

virescens. Hass.

viridis. Kutz.
Falxnella. Lyngb. . .

adnata. Lyngb. .

ceruginosa. Carm. .

cruenta. Ag.

cryptophila, Carm.

frustulosa. Carm. .

granosa. Berk. . .

hyalina. Breb. . .

livida. Carm. . .

miniata. Nag.

montana. Ag.

Mooreana. Harv.

mucosa. Kutz. . .

myosurus. Lyngb. .

nivalis. Hook. .

prodigiosa. Mont. .

Ralfsii. Harv. .

rivularis. Carm.

nyjestris. Lyngb. .

sanguinea. Ag. .
PALMELLACE^E. . . .
Palmodictyon. Kutz.

rnfescens. Kutz.

viride. Kutz. . . .
Fandorina. Elir. . .

el eg ana. Duj.

morum. Ehr. . .
PEDIASTEE^E. . . .
Fediastrum. Mey.

augulosum. Ehr.

bidentuluni. Br.

biradiatum. Ralfs. .

Boryanum. 0. Kalfs.

Boryanum. Ralfs. .

Boryanum. Turp. .

brachylobum. Br. .
,, var. clatlir

cribrifonne. Hass. .

cuspidatum. Br.

constrictum. Hass. .

Ehrenbergii. Br.

elegans. Hass.

ellipticum. 0. Ralfs.

ellipticum. Ralfs. .

excavatum. Hass. .

excisum. Br.

gracile. Br. . .

granulatum. Br.

grauulatum. Ralfs.

PAGE

. . 247

. . 248

. . 251

. . 247

. . 249

. . 254

. . 261

. . 248

. . 254

. . 249

. . 11

. . 8

. . 207

. . 13

. . 10

. . 30

. . 218

. . 11

. . 205

. . 12

. . 208
12,218

. . 11

. . 25

. . 54

. . 12

. . 209

. . 210

. . 7

. . 209

. . 3

. . 14

. . 15

. . 15

. . 67

. . 67

. . 68

. . 40

. . 40

. . 41

. . 42

. . 44

. . 43

. . 41

. . 42

. . 43
atuni. 43

. . 43

. . 44

. . 42

. . 44

. . 41

. . 42

. . 43

. . 41

. . 44

. . 43

. . 42
42

324

INDEX.

PEDIASTRUM — (continued)

hexactis. Hass. . . .

heptactis. Hass. . .

heptactis. Ralfs. . .

incisum. Hass. .

lunare. Hass.

Napoleonis. Hass. . .

Napoleonis. Ralfs. . 41,

pertusum. Kutz.

rotula. Ehr

selensea. Kutz. . . .

selencsa. Pritch . . .

simplex. Hass. . . .

simplex. Ralfs. . . .

tetras. Ralfs. ... .

tricyclum. Hass.

trnncatum. Br. . .
Petalonema. Berk. . .

alatum. Berk. . . .
Petronema. llnv.

fruticulosum. Thw.
PHORMIDIUM.

corium. Ag

inundatum. Kntz. .

2?apuraceum. Rabh.

papyrinum. Kutz. .

rupestre. Kutz. . . .

subfuscum. Rabh.

vulgare. Kntz.
PHYCASTRUM.

longispinum. Perty.
PHYCOCHROMOPHYCE^E. .
PHYLLACTIDIUM.

pulchellum. Kutz. .

setigerum. Kutz. . .
PHYSACTES.

pisum. Kutz. . . .
Fithophora. Wittr. . .

Kewensis. Wittr.

PlTHOPHORACE.E. . . .

Flectonema. Thur. . .

Kirchneri. Cite. . .

mirabile. Kirch. . .

mirabile. Thur. . . .
PLEUROCARPUS.

compressus. Rabh. .

mirabilis. Br.
Pleurococcus. Men. . .

angulosus. Men. . . .

Beigelli. K. cO R. . .

bitnminosus. Men. . .

cohcerens. Breb. . .

miniatus. Nag. .

(?) mucosus. Rabh.

roseo-persicinus. Rabh.

Superbus. Cien. .

vestitus. Rein. .

vulgaris. Men. .
POLYCTSTIS.

ceruginosa. Kutz. . .

PAGE

. 42
. 45
. 44
. 45
. 41
. 44

42,43
. 43

. 45
. 41
. 43
. 44

42,43
. 44
. 44
. 44
. 267
. 267

275

261

259
260

260
260
262
259

. 32
. 203

. 197
. 196

. 282
. 146
. 147
. 146
. 263
. 264
. 264
. 263

105

105

3

4

4

296
204
6
4
6
7

296
3

, 212

POLYEDRIE^E

Polyedrium. Nag. . .
enorme. Rabh. . . .
gigas. Wittr.
longispinum. Rabh.
tetraedricum. Nag.

PORPHYRACE.E

Fxasiola. Ag

calophylla. Spr. .

crispa. Kutz

furfuracea. Men.

stipitata. Sulir. .
Forphyridium. . . .

cruentum. Nag. . . .

PRASIOLE^E. . . . . .

PROLIFERA.

Borisiana. L/C1. . . .

Boscii. L.C1

ri/uularis. L.C1. .

Rothii. L.C1

Vaucherii. L.C1. .
PEOTOCOCCACBJBJ. . . .

PROTOCOCCE.E

Pxotococcus

angulosus. Ca.

cohcerens. Kutz. . .

communis. Kutz.

crustaceus. Kutz.

gigas. Kutz

magma. Men.

monospermus. Corda .

mucosus. Kutz. .

nivalis. Ag

palustris Kutz. . . .

plurialis. Kutz. . .

roseo-persicinus. Kutz.

turgidus. Kutz. . . .

umbrinus. Katz.

viridis. Ag

vulgaris. Kutz. . . .
Rhaphidium. Kutz. . .

aciculare. Br. . . .

duplex. Kutz. . . .

falcatum. Corda. . .

polymorphism. Rabh. .

triplex. Rabh. . . .
Rhizoclonium. Knt~.

Casparyi. Harv. . . .

flavicans. Jurg. . . .
RHIZONEMA.

interruptum. Thw. .
Rhizophydium. Sch.

Barkerianum. Ar. . .

RHODOPHYCEYE

RHYNCHONEMA.

abbreviation. Kutz.

affine. Kutz

angulare. Kutz. . .

diductum. Kutz.

PAGE
. 31
. 31
. 32
. 31
. 32
. 32
. 282
. 128
. 130
. 128
. 129
. 129
. 13
. 13
128

162

168

169

159

156

29

29

29

4

201
4

297

31

208

51

4

54

4

51

6

204

297

29

4

19

19

20

19

19

20

140

140

141

266
199
199

282

93
93
92
96

INDEX.

325

RHYNCHONEMA — (continued)

diibium. Kutz. . .

gallicum. Eiparfc. . .

Jenneri. Kutz. . .

malleolus. Kntz. . .

iiti.niniu.in. Kutz.

quadrata. Kutz. . . .

reversion. Kutz. .

rostratum. Kutz.

Woodsii. Kutz. . . .
Rivularia, Roth. . . .

angulosa. Kutz. .

botryoides. Carm. .

calcarea. E. Bot.

Crustacea. Carm. . .

dura. Kutz

echinata. E. Bot.

elegans. E. Bot. .

yigantea. Fisch. . . .

granulifera. Carm. . .

incrassata. Purt.

Lin Ma. Roth. . . .

natans. Gray.

pisum. Ag

plana. Harv. . . .

prunifornds. Purt. .

radians. Kirch. . . .

tuberculosa. E. Bot. .

tubulosa. D.G.
SARCINA.

renis. Hepw.

ventriculi. Good.

SCENEDESME.E

Scenedesmus. Mey. . .

acutus. Mey.

antennatus. Breb. . .

dimorphus. Ralis. .

duplex. Ralfs.

oblic[uu8. Ralfs.

obtusus. Mey. . . .

quadricauda. Breb.

quadrieaudatus. Ralfs.

triseriatus. Ralfs. .
Schizochlamys. Br. . .

gelatinosa. Br.
Schizogonium. Kutz.

rnurale. Kutz. . .
SCHIZOSIPHON.

cataractce. Nag. . .
Sciadium. Br

arbuscula. Br. . . .
Scytonema. Ag. . . .

Bangii. Lyngb. . . .

byssoJdeum. Harv. .

cinereum. Mtn.

cirrhosum. Berk.

cirrliosum. Carm.

Compactum. Eng. Fl. .
crustuceum. Ag.
Hqffmanni. Ag. . . .

PAGE
. 97
. 94

. 97
. 93
. 96
. 95
. 92
. 88
. 91
. 277
. 281
. 280
. 279
. 280
. 279
. 278

28L
280
195
227
281
282
281
281
279
194
16

215
215
32
33
33
34
35
20
34
33
34
35
34
10
11
183
184

. 276
39
39

. 264
. 2G3
. 274
. 2G5
276
. 270
. 272
. 275
. 267

SCYTONEMA — (continued}
inteiTUptuui. Thw.
Julianum. N. & Witt. .
ininutum. Harv.
myoclirouS. Ag..
natans. Breb. . . .
ocellatum. Harv. . .
pannifonne. Ag. . .
turfaceum. E. Bot.

SCYTONEME^E .....
SCYTOSIPHON.

intestinaUs. Gray. .
Selenastxum. Rein. . .

Bibraianum. Rein.
SEPTORIA.

anemones. Fckl.
SERPENTARIA.

compressa. Gray. . .
genufevo. Gray.

SlPHOrHYCEyE ....

Sirogonium. Kutz. . .

Jjraunii. Kntz. . . .

breviarticulatum. Kutz.

sticticum. Kutz. . .
SlROSIPHON.

Bouteillii. Breb.

compadus. Kutz. . .

ocellatns. Kutz. . .

panniformis. Kutz.

p id r hiatus. Breb. . .

Saxicola. Johns.

truncicola. Rabh. . .

Sorastium. Kutz. . .

spinulosum. Nag. .
SOROSPORA.

rjruinosa. Hass. . .

inontana. Hass. . .

Ralfsii. Hass. . .

virescens. Hass. . .
SPERMOSIRA.

Rarveyana. Thw. .

litorea. Kutz. . .

Spn.KROCAKPUS.

augustus. Hass. . .
depresses. Hass.
intricatus. Hass.
nummuloides. Hass.
ovalis. Hass
parvulus. Hass. . .
recur rirs. Hass. . .

SPn.lCKOXKMA.

anemones. Lib. . .

Sphaeroplea. Ag. . .
amiulina. Ag. . .

rri^jKi. Jjc-rk. . .

SPH^EHOPLEACE.E. . .
SPH^JEOBIBA.

volvox. Ehr.

PAGE
. 266
. 266
. 273
. 2G5
. 265
. 271
. 272
. 273
. 264

131

47

47
201

105
105
111

97
97
97
97

271
272
271
272
273
273
274
45

46

46

12
208
209
210

245
244

104
103
104
103
103
104
105

201

, 132
134

, 181
132

64

326

INDEX.

Sphaerozyga. Ag. . . .

Berkeleyana. Thw.

Broomei. Thw. . . .

Carmichaeli. Harv.

elastica. Ralfs. . . .

flos-aquce. Rabh.

Hassallii. Rabh.

incequalis. Kutz.

Jacob! . Ralfs. . . .

leptosperuia. Ralfs.

Mooreana. Ralfs.

oscillarioides. Kutz.

Ralfsii. Rabh.

Thwaitesii. Harv. . .

varidbiUs. Kutz. . .
SPIRILLUM.

Jenneri. Hass. . . .

minutissimum . Hass. .

rupestre. Hass. .
Spirogyra. Link. . . .

affinis. Petit.

alternata. Kutz. . .

arcta. Kutz

Braunii. Rabh.

bellis. Hass

calospora. Cleve.

catena for mis. Kutz.

com/munis. Kutz.

condensata. Vaucli. .

crassa. Kutz. . . .

decimina. Kutz. . .

flai'icans. Kutz. . .

flavescens. Hass. . .

Flechsigii. Rabh. . .

gastroides. Kutz. . .

gracilis. Kutz. . . .

Hantschii. Rabh.

Hassallii. Petit. . .

Heeriana. Kutz.

inflata. Kutz. . . .

inflata. Rabh.

incequalis. Kutz.

insignis. Hass. .

jugalis. Dilliv. . .

laxa. Kutz

longata. Vauch.

major. Kutz.

majuscula. Kutz.

mirabilis. Kutz. . .

Ncegelii. Kutz. .

nitida. Dillw. . . .

nodosa. Kutz.

orbicular is. Hass. .

orthospira. Nag.

parrot. Kutz

2)orticalis. Petit. . .

porticalis. Vauch. . .

protecta. Wood. . .

princeps. Cleve.

quadrata. Petit. . .

PAGE
. 240
. 241
. 241
. 240
. 243
. 240
. 236
. 239
. 242
. 242
. 242
. 238
. 237
. 236
. 236

. 245
. 246
. 247
. 83
. 93
. 88
. 91
. 94
. 88
. 94
. 93
. 92
. 91
. 85
. 90
. 90
. 93
. 91
. 96
. 93
. 94
. 94
. 85
. 91
. 97
. 96
. 94
. 86
. 90
. 92

90

. 87
. 92

96
. 86

91

. 87
. 87
. 93
. 90
. 89
. 95
. 86

95

SPIBOGYRA — (continued')
quinina. Kutz.
rirularis. Rabh.
setiformis. Kutz.
setiformis. Petit.
subesqua. Kutz.
subtilis. Kutz. . .
tenuissirna. Harv. .
torulosa. Kutz. .
turpis. Kutz.
ulotrichoides. Kutz.
varians. Kutz. . .
velata. Nordst. .
ventricosa. Kutz. .
Weberi. Kutz. . .
Weberi. Rabh.

Spixulina. Link. . . .

brevis. Kutz

Jenneri. Kutz. . .

oscillarioides. Turp.

rupestre. Rabh. . . .

tenuissima. Kutz. . .
STAURASTRUM.

enorme. Ralfs.

falcatum. Ehr. . . .
STAUROCARPUS.

affinis. Hass. . . .

capucinus. Hass. . .

ccerulescens. Hass.

glutinosus. Hass.

gracilis. Hass. . . .

gracillimus. Hass. . .

quadrangulatus. Hass.

quadratus. Hass.

virescens. Hass.

Staurogenia. Kutz. . .
rectaugularis. Br. . .

Staurospermum. Kutz. .

capucinum. Kutz. . .

franconicum. Rein.

gracillimum. Hass.

notabile. Rabh. . . .

quadratuui. D. By. .

viride. Kutz. . . .
Stephanosphaera. Cohn.

pluvialis. Cohn.
Stigeoclonium. Kutz. .

fastigiatum. (Ralfs.) .

nanum. (Dillw.) . . .

protensum. (Dillw). .

tenue. Ag

thermale. Br.

Stigonema. Ag. . .
Bonteillii. (Bret.) .
compactum. (Kirch.)
inter r upturn. Hass.
mamillosum. Ag. .
minutum. Hass.
ocellatnm. Thur. .
panniforme. Kirch.

PAGE

. 90

. 90

. 88

. 86

. 88

. 92

. 96

. 92

. 93

. 91

. 91

. 297

. 96

. 95

. 96

. 245

. 246
. 245
. 246
. 247
. 246

. 32
. 19

. 107
. 107
. 107
. 107
. 107
. 106
. 106
. 106
. 107

. 46

. 46

. 106
. 107
. 107
. 106
. 110
. 106
. 107
. 71
. 71
. 188
. 191
. 190
. 190
. 189
. 189
. 270
. 271
. 272
. 266
. 272
. 273
. 271
, 271

INDEX.

327

STIGONEMA — (continued)

saxicolum. Nag.

turfaceuin. Berk. .

SUPPLEMENT

Symphyosiphon. Kutz.

Hoffmann!. Kutz. .
Symploca. Kutz. . . .

lucifuga. Harv.

Ralfsiana. Kutz. .
Synchitrium. D.By . .

anemones. Woron.

mercurialis. Fckl.

Taraxaci. D.By. . .
Synechococcus. Nag. .

crassns. Ar. . . .
Tetrapedia. Rein. . .

Crux-Michaeli. Rein. .

Keiuschiana. Ar. .

setigera. Ar. . .
Tetraspora. Link. . •

bnllosa. Ag

flava. Hass

gelatinosa. Vauch,

lubrica. Both. . . .

minima. Desv. .
TETRASPORELLA.

lubrica. Gaill. . .
Thoxea. Bory

ramosissima. Bory. .
THWAITESIA.

Durieei. Mont. . . .
Tolypothrix. Kutz. . .

Eegagropila. Kutz. .

cirrhosa. (Garni.) .

coactilis. Kutz.

Dillwyni. Harv. . .

distorta. Hass. . .

distorta. Kutz. . .

flaccida. Kutz. .

muscicola. Kutz. . .

punctata. Hass.

pygmcea. Kutz. .
TORTJLA.

mesomela. Carm. . .
TREMELLA.

adnata. Hnds. .

crisp a. With. . . .

cruenta. Eng. Bot.

Dama cornuum. Dill. .

granulata. Huds. .

marina. Dillen. . .

nivalis. Brown. . . .

nostoc. Linn. . . .

palustris. Dillen. .

utriculata. Huds. .

verrucosa. Huds. .
TRENTEPOHLIA.

aureus. Ag

chalybea. Johnst. .

corymbifera. E. Bot. .

PAGE

. 273

. 272
. 276
. 267
. 267
. 262
. 262
. 263
. 200
. 201
. 201
. 201
. 217
. 217
. 215
. 216
. 216
. 216
. 15
. 16
. 16
. 16
. 16
. 16

. 16
. 293
. 293

. 80
. 268
. 269
. 270
. 2G9
. 276
. 269
. 268
. 268
. 269
. 269
. 269

. 187

. 8

. 128

. 13

. 195

. 114

. 130

. 54

. 231

. 114

. 281

. 234

. 186

. 284
. 284

TRENTEPOHLIA — (continued) PAGE
iolithus. Wallr. . . .186
pulchella. E. Fl. . . . 284
pulchella. Hass. . . . 284

TRICHIPHOREJ; ...... 275

TRICHORMUS.

incur vus. All ..... 235
oscillarioides. Ralfs. . . 238
rectus. Ealfs ..... 236

spiralis. Kalfs
Thwaitesii. Ralfs. .
TYNDARIDEA.

abbreviata. Hass. .
anomala. Hass. •
bicolor. E. Bot. .
biornis. Hass
conspicua. Hass. .
cruciata. Harv. .
cruciata. Hass. .
decussata. Hass. .
immersa. Hass. .
insignis. Hass. .
interposita. Hass. .
lutescens. Hass. .
ovalis. Hass
pectinata. Eng. Fl.

235
236

81
81

80
77
81
79
77
77
83
80
81
80
77

Ralfsii. Hass ..... 78
stagnalis. Hass ..... 81
stagnicola. Hass. . . 81
stellina. Jenn ..... go

Ulothrix. Kutz ...... 181

aequalis. Kutz ..... 180

bicolor. Ralfs ..... 181

catenasformis. Kutz. . -180
crispa. Kutz ...... 181

moniliforinis. Kutz. . . 179
parietina. (Vauch.) . . 183
radicans. Kutz ..... 182

speciosa. Kutz ..... 181

subtilis. Kirch ..... 182

tenerrirna. Kutz. . . . 182

tenuis. Kutz ...... 182

variabilis. Kutz. . . . 182

zonata. Kutz ..... 179

ULOTRICHE^E ....... 178

ULVA.

bullosa. Roth ..... 16

calopliylla. Hass. . . . 130

crispa. Hass ...... 128

furfuracea. Grev. . . . 1^<)

gelatinosa. Vauch. . . . 16

granulata. Light. . . .114

incrassata. E.Bot. . . . 195

intestinalis. Huds. . . . 130

lactuca. J. Huds. . . .128

lubrica. Roth ..... 16

marina. Ray ..... 130

montana. Lightf. . . . 208

pisiformis. Huds. . 194, 232
pr uniform is. Huds. . . 233

328

INDEX.

ULVA — (continued)

terrestris. Gray.

ULVACE.E

ULVEJG

UREDO.

nivalis. Bauer. . .
Urococcus. tfass. . .

Allmanni. Hass. .

cryptophylus. Hass.

Hookerianus. Hass.

insiguis. Hass. . .
VAGINARIA.

chthonoplastes. Grev.

vulgaris. Gray. .
Vauchexia. D. C. . .

aversa. Hass. . .

circinata. Kutz.

clavata. Vauch. . .

Gtsspitosa. Vauch. .

dichotoma. Lyngb. .

Dillwyni. Ag. . .

Dillwyni. Rabh.

geminata. Walz.

globifera. D.By. . .

graniilata. Grev.

harnata. Walz. .

liamulata. Kutz.

multicapsiilaris. Harv.

ornitJiocephala. Ag.

ornithocephala. Hass.

ovata. Gray. . . .

ovoidea. Hass. . .

pachyd&rma. Walz.

polysperma. Hass. .

racemosa. Harv.

racemosa. Rabh.

radicata. Hook. . .

rep ens. Hass. . . .

rostellata. Kutz. . .

salina. Kutz. .

sericea. Lynyb. .

sessilis. Vauch. . .

spJicsrocarpa. Kutz.

submar'ma. Berk.

terrestris. Lyngb.

Unyeri. Thur. . .
VAUCHERTACE^. . . .
VESICULIFEHA.

(pqvale. Hass. . .

affinis. Hass. . . .

alata. Hass. . . .

Boscii. Hass. . .

Candollei. Hass.

capillaris. Hass.

cardlaca. Hass. . .

ciliata. Hass. . .

compressa. Hass.

concatenata. Hass. .

condensata. Hass. .

crassa. Hass. .

PAGE

. 128

. 128

130

54
9

10

10

9

9

256
256
116
121
126
123
123
120
122
125
125
120

. . 126

, . 126
. 114

. . 121

. . 124

. . 125

. . 125

, . 122

. . 121

. . 125

. . 123

. . 114

. . 124

. . 121

. . 120

. . 121

. . 123

. . 123

. . 120

. . 126
123, 122
115

160
152
152
168
155
171
166
164
165
163
152
173

152
172
168

VESICULIFKRA — (continued) PAGE

crifijta. Hass 155

Curler i. Hass 152

dissiliens. Hass. . . . 152

dubia. Hass 152

elegans. Hass. .... 168

fasdata. Hass 170

flavescens. Hass. . . . 161

hexagona. Hass 170

incequalis. Hass.
lacustris-. Hass. . .
LandsborougMi. Hass.

Mutter I, Hass 152

ovata. Hass 169

paludosa. Hass 156

princeps. Hass 171

pulcliella. Hass. . . .166

Ralfsii. Hass 152

Rothii. Hass 159

spTwerica, Hass 152

Vaucheri. Hass 156

vernalis. Hass 155

virescens. Hass 152

VOLVOCINE^E 50

Volvox.Liim 56

aureus. Ehr 64

globator. L. ..... 63

minor. Stein 64

stellatus. Ehr 64

ZONOTRICHIA.

calcarea. Rabh 279

ZOOGALACTINA.

imetroplia. Sette. ... 12

Zygnema. Kutz 76

abbreriatum. Hass. . . 92

cestivum. Hass 92

affine. Hass 93

alternatum. Hass. ... 88

angular e. Hass 92

angiilatum. Hass. ... 92

anonialum. Hass. ... 81

bella. Hass 88

bipnnctatum. Grev. . . 77

bipundatum. Johnst. . . 79

commune. Hass. ... 92

compressum. Lyngb. . . 105

crudatum. Vauch. ... 79

curvatum. Ag 97

deciminum. Hass. . . . 9o

diductum. Hass. ... 96

Dillwyni. Kutz. ... 79

dubium. Hass 97

flavescens. Hass. ... 93
genu flexum. Johnst. . .105

gracile. Berk 99

gracile. Hass 93

Grevilleanum. Hass. . . 96

Hassallii. Hass. ... 94

incequale. Hass. ... 95

inflation. Eug. Bot. . . 90

INDEX.

329

ZYGNEMA — (continued)
inflation. Hass. . .
insigne. Hass.
insigne. Kutz. . .
intermedium. Hass.
interruption. Hass.
Jenneri. Hass.
leiospermum. D. By.
longatum. Hass.
malformatum. Hass.
malleolum. Hass.
maximum. Hass.
minimum. Hass.
inirabile. Hass. . .
neglectum. Hass.
nitidum. Lyngb.
orbicular e. Hass.
ordinarium. B. .
parvnlum. Kutz.
parvum. Hass. .
pectinatum. Ag.
quadratum. Hass. .
quininum. Hass.
Ealfsii. Kutz. . .
reversum. Hass.
rivulare. Hass. . .
rostratum. Hass. .
serratum. Hass.

PAGE
. 97
. 94
. 83
, 95
. 88
. 97
. 82
. 96
. 92
. 93
. 88
. 96
. 92
. 89
. 85
. 88
. 78
. 78
. 93
. 77
. 95
. 89
. 78
. 92
. 90
. 87
85

Z VGNEMA — (continued)

sjriralis. Eng. Bot.

stellinum. Vaucli. . .

subventricosiim. Hass.

tenue. Rabh. . . .

tennissimum, Hass.

varians. Hass. . . .

Vaucherii. Ag. . . .

ventricosum. Hass.

Woodsii. Hass. .

ZYGNEMACE.E

ZYGNEME^E

Zygogoniuxn. Kutz. . .

Agardhii. Eabh. . .

conspiciium, Ktitz. . .

decussatum. Kutz. .

didymum. Rabh. . .

ericetorum. D.By.

gracile. Berk.

immersum. Kutz.

Iceve. Kutz

parvulum. Kutz. . .

pectinatum. Rabh.

pleurospermum. Kntz.

Ralfsii. Kntz.

torulosum. Kutz. . .
ZYGOPHYCE^;.

PAGE
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. 83
. 96
. 91
. 80
. 96
. 91
. 74
. 76
. 98
. 99
. 77
77
99

. 98
. 99
. 77
. 100
. 78
. 77
. 105
. 78
. 98
74

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