On new plants from the Erian and carboniferous, and on the characters and affinities of palaeozoic gymnosperms

PETER REDPATH MUSEUM, McGiLL UNIVERSITY, MONTREAL,

NOTES ON SPECIMENS, 1890.

ON NEW PLANTS FROM THE BRIAN AND CARBONIF-
EROUS, AND ON THE CHARACTERS AND

AFFINITIES OF PALAEOZOIC G-YMNOSPERMS.1

BY Sm J. WILLIAM DAWSON, L.L.D., F.R.S.

In Palseo-botany it often happens that some specimen
recently discovered opens up a multitude of new questions
respecting former acquisitions. A noteworthy instance of
this in my recent experience, h^s been the kind communica-
tion to me by Mr. E. D Lacoe of Pittston, Pennsylvania, of
some specimens of Palaeozoic Gymnosperms obtained by him
in the Catskill and Carboniferous of Pennsylvania. One of
these is a large slab containing a leafy and fruit-bearing
branch or stem of a new plant allied to Cordaitese on the one
hand and to Nceggerathisa on the other, and remarkable
for its exhibiting in connection parts usually found separ-
ately. Another is a set of specimens of certain peculiar
organs of fructification referred by European palseo-botanists
to the genus Dolerophyllwn, allied to JSTceggerathia, and which
have not, so far as I am aware, been previously found in
America. About the same time Mr. Francis Bain, of North
Eiver, Prince Edward Island, had placed in my hands some

1 Reprinted from the CANADIAN RECORD OP SCIENCE, January, 1890.

very interesting examples of the stems known as Tyloden-
dron, which occur not infrequently in the Permian of that
Island, and of which he has found the leaves and probably
the fruit along with stems shewing markings and struc-
ture.

FIG. 1. Dictyo-cordaites, Lacoi — much reduced ; (a) venation of
leaf nat. size ; (6) seed and bract, enlarged.

A short notice of Mr. Lacoe's remarkable specimen was
sent at once to the American Journal of Science,1 but the
1 July, 1889.

3

questions raised by this and the other specimens demanded
a more detailed investigation ; and I now wish to base on
this, and the other specimens above referred to, some gene-
ral remarks on our present knowledge of Palaeozoic
Gymnosperms, and more especially on those of North
America.

Mr. Lacoe's large specimen, for which I have proposed the
generic name Dictyo-cordaites in reference to its peculiar
netted venation, may be described as follows l : —

DIOTTO-OORDAITES I/Acoi, Dawson. (Fig. 1)

The specimen is a branch or small stem 2 \ cm. in diameter
and 46 cm. in total length- It is flattened and pyritised,
and shows, under the microscope, only obscure indications
of the minute structure, which would seem to have consisted
of a pith surrounded by a fibrous envelope and a bark of no
great thickness. It would appear, therefore, to be exogenous
with a thin woody cylinder and large pith. The stem shows
portions of about 15 leaves, which have been at least 16 cm.
long and 3 to 4 cm. broad. They are spirally arranged and
are decurrent, apparently by a broad base, on the . stem.
Their distal extremities are seen in a few cases, but in all
seem injured by mechanical abrasion or decay. It seems
most probable that they were truncate and uneven at their
extremities. The stem is terminated by a cluster or com-
pound corymb of spikes of which 20 are seen. They are
slender, but seem to have been stiff and woody, and the lar-
gest are about 15 cm. in length. The peduncles are knot-
ted and wavy in outline, as if dry and woody in texture
when recent. In this they differ from most of the ordinary
Antholites, but agree with my A. Devonicus,'2 and also with
A. rhabdocarpi of the Carboniferous3 which they resemble
in the form and arrangement of the fruit. They have short

1 I am indebted to Professor Penhallow, of McGill University,
for his kind aid in the study of the specimen.

2 Fossil Plants of Devonian and Upper Silurian, 1871, Plate XIX.

3 Journal London Geological Society, 1867, Plate VII.

pointed bracts, and some of them bear oval fruits, but only
a few of these remain, the greater part of them having ap-
parently fallen off before the plant was fossilized. There
may have been about 50 to 100 seeds or fruits on each peduncle,
and they seem to have been spirally arranged. So far the
characters do not differ from those of the genus Cordaites,
except that in those plants the spikes of fructification are
more usually lateral than terminal. Grand 'Eury, however,
figures1 one : form of Cordaicladus in which they are ter-
minal.

The most remarkable peculiarity, however, appears in
the leaves, which instead of having the veins parallel, have
them forking at a very acute angle, and slightly netted by
the spreading branches of the veins uniting with the others
near them. This allies the leaves with those of the pro-
visional genus Noeggerathia, some of which have this pecu-
liarity, as also certain modern Cycads of the genus Zamia,
which Professor Penhallow has kindly pointed out to me.
Leaves with forking veins and even anastomosing to a certain
extent, are also known in certain fossils of the genera Otoza-
mites and Nosggerathiopsis, &c.. which are referred to Cycads,
and the modern Cycadaceous genus Stangeria has forking
veins. The present plant would seem to be a form of Cordaitese,
tending to Nceggerathia, which most paleo-botanists believe to
have been a gymnospermous genus allied to Cordaites. The
affinities however, so far as can be judged, are nearer to the
latter ; and following the example of Grand 'Eury in his
nomenclature of the genera, I would propose the name
Dictyo-cordaites for the present genus, and the specific
name JLacoi, in honor of its discoverer. I may add here that
the general aspect of this plant must have been so near to
that of a Carboniferous species of Cordaites, as restored
many years ago in my Acadian geology,2 that I reproduce
the figure here.

1 Flore Carboniferce, PI. XXV, Fig. 4.

2 Second Edition, 1868, Page 458, figure 172.

FIG. 2. Eestoration of Cordaites borassifolia. (1) Stem,
(2) leaf, (3, 4) base and point of leaf, (5) section of
stem. B. Markings of Diplotegium, an allied type
(from Acadian Geology.)

6

The specimen thus invites a comparison with the families
of Cordaiteae and Noegerrathiae in connection with allied
genera and with a number of discoveries made in recent
years with reference to the Gymnosperms of the Palae-
ozoic.

Mr. Lacoe's specimen is flattened out on a slab of grey
sandstone, and was collected by him in the Lower Catskill
(Upper Devonian) of Meshoppen, Wyoming Co., Pennsyl-
vania. Mr. Lacoe informs me that it is there associated
with Archasopteris minor and A, major, Lesqx., and in neigh-
bouring quarries half a mile distant and about fifty feet
higher in the series, there are different species of Archaeop-
teris, including one identified with A. Hibernicus, and a stro-
bile apparently of Lycopodites Richardsoni, a form character-
istic of the Upper Devonian of Perry in Maine. These beds
have also afforded to Prof. White a species of Spirifer, and
the Stylonurus excelsior of Hall.

I may add that I described, some years ago,1 under the
name Noeggerathia G-ilboensis, a specimen from the collection
of Mr. Lockwood of G-ilboa, New York, and from the
Cheming group, which was kindly communicated to me by
Prof. Hall. It differs from the present species in the form
of the leaves and also in the veins being simple and appar-
ently of two orders. Its characters are as follows : — " Leaf
rhombic-obovate, with a broad base. Nerves or radiating
plicae nine in number, not forked, and with fine striae
between them. Length 3T% inches. Breadth 2J inches. It
seems to have been bent in a conduplicate manner, and clasp-
ing or decurrent, on a stem or branch. The form tends to
that of Dolerophyllum, though the species has been referred
to Nceggerathia."

I may also add that the only undoubted Devonian Cordai.
tes previously in my collections, is C. Robbii from the middle
Devonian of St. John, New Brunswick. This is a long and
broad parallel-sided leaf, pointed at the extremity, and clasp-
ing at the base, with parallel veins, and nearly akin to G.
borassifolia of the Carboniferous. With it are found species

1 Quarterly Journal Geological Society, 1871.

of Antholithes, and of Gardiocarpon, which may have belonged
to it.1 It would thus seem that so far as now known in America
the typical Cordaites had precedence of the NoeggerathisB,
and of Dictyocordaites. My narrow-leaved species G.
angustifolia is equally ancient with G. Robbii, but is of
doubtful affinities.

DOLEROPHYLLUM, Saporta.

This genus was established by Saporta for certain densely
leaved plants, having rounded leaves with radiating nerves
and closely arranged in a spiral manner on the stem. The
male inflorescence of these plants consists of a central disk,
with cavities for the pollen, and surrounded with radiating
fibres, while the seed is of large size and longitudinally
striated, being the fruit usually known as Rhabdocarpus. It
is likely that in America we have usually placed the leaves
with ferns, as species of Cyclopteris. The fruits are
known and have been described as Rhabdocarpi. One
species, my Rh. insignis from Nova Scotia, is an inch and a
half in length. Another, Rh. oblongatus of Fontaine, from
Virginia, is nearly as large. Mr. Lacoe has found separate-
ly what is regarded as the male organ of fructification-. One
of his specimens is a nodule of clay ironstone from Illinois,
and exhibits merely the central disk. Two others are flat-
tened in shale and are from the Carboniferous of Pennsylva-
nia. They are of different sizes, but may be of the same
species. The larger of the two has a disk three quarters of
an inch in diameter, and marked with pits and ridges in an
irregularly radiating manner, while the border of radiating
fibres is about half an inch in breadth, giving a total diameter
of an inch and three quarters.

If we put together the leaves of some of the larger specias
of Cyclopteris, the fruit of Rhabdocarpus, and these singular
disks, we shall have all the principal parts of Dolerophyllum
as restored by Saporta from actual specimens found in the

1 Report on Devonian Plants of Canada, 1871.

8

coal measures of France.1 I have not in my own collections
any specimens proving this collocation of parts, but give it
here on the authority of the French palseo-botanist. The
structure of the stem of Dolerophyllum does not appear to be
known, but its affinities would seem to be Cycadean, and the
organs of fructification above described have some re-
semblance to the remarkable Carpolithes horridus of our Cre-
taceous of the North-west.2 The species collected by Mr.
Lacoe so closely resembles D. Gospperti of Saporta, that I
hesitate to give it a specific name. It may, however, be
distinguished by its longer marginal rays and larger pits on
the disk, and may be provisionally named D. Pennsyl-
vanicum.

TYLODENDRON, Weiss.

A very important class of fossils in connection with the
subject of this paper is that included in the genus Tylodendron
of Weiss, which are more characteristic of the upper than
the lower members of the later Palaeozoic. They are, how-
ever, closely allied to some of the forms included in the
genus Knorria, which goes back to the Devonian. These
stems are characterised by elongated ridges spirally
arranged, and with a slight groove at one end. Some speci"
mens also show distinct swellings or nodes of larger scars
as if giving origin to whorls of smaller branches. They are
most frequently sandstone casts , and the surface markings
are not those of a true exterior surface, but of an inner cylin-
der showing the points of exit of bundles of fibres or ves-
sels. These stems have received several names. They
constitute the genera Schizodendron and Angiodendron of
Eichwald, and the Lepidodendron elongatum of Brongniart is
is apparently of this nature. It is difficult to distinguish them
into good species, and the T. speciosum of Weiss covers most
of the forms. Weiss has described the structure of the
stem as consisting of a cellular pith surrounded with a

1 Evolution des Plantes, Phsenogames, p. 75.

2 Trans. B. Socy. of Canada, Vol. I, p. 21, PI, I., Fig. 3.

f '
9

cylinder of porous discigerous fibres, with three rows of
contiguous pores, and radially arranged. This is of course
near to Dadoxylon. The stem and fruit have not hitherto
been recognised in Europe.

These plants were first recognised in Prince Edward
Island by the writer in 1870, and published in his report on
the geology of the Island in 1871, under the generic name
ofKnorria. They are there stated to " resemble very closely
the Permian stems to which Eichwald has given the name
Schizodendron." They are also stated to show traces of
woody tissue allied to that of Conifers, and are conjectured
to have been branches of trees allied to that family. Jn
that Report they are said to occur in the Permo-Carbonif.
erous of Gallas Point, and also in beds referred to the
Trias.

Additional specimens were subsequently collected by Mr.
Bain of North River, Prince Edward Island, and were sent
to me for examination. They are described in a paper pub-
lished in the Canadian Naturalist in 1885 as follows : —

"Tylodendron was founded by Weiss to include stems
with elongate, prominent leaf-bases of the character of those
of Knorria, but bifurcate at the top. These stems or
branches, are very characteristic of the Permian of Russia,
Germany and France. They have been found by Weiss to
show the character of Dadoxylon when the structures are
preserved, and are therefore Coniferous; and it is now
pretty generally believed that they are decorticated bran-
ches of Walchia. So far as European evidence extends, they
are regarded as strictly Permian, and the species drawn by
Mr. Bain is not distinguishable from T. speciosum of Weiss.
In Prince Edward Island, I have figured (Report, Plate III
Fig. 30) what seems to be the same species, though under
Knorria ; but my specimen may have been from the Middle
Series, then called Lower Trias, but now regarded by Mr.
Bain as Permian.1

1 Mr. Bain informs me in a recent letter that he has found speci
mens of Tylodendron in beds regarded by him as Triassic.

10

The specimens were associated with branches of Walchia,
leaves of Cordaites Simplex, Trigonocarpa, and also with
[trunks of Dadoxylon (D. materiarium.)

Since the publication of the paper
referred to, Mr. Bain has made addi-
tional collections, more especially on
St. Peter's Island and other places on
the south side of Prince Edward Island,
some of which have been sent to the
Geological Survey at Ottawa, and
others to the writer, along with draw-
ings of specimens still in Mr. Bain's
possession. These specimens show the
internal structure of the pith and woody
cylinder, and varieties in the external
markings which may perhaps indicate
distinct species; and along with the
stems, M r. Bain has found leafy branch-
lets and fruits of a peculiar form which,
from their association, he regards as be-
longing to these plants.

The principal external differences in
Mr. Bain's specimens, consist in greater
or less size and distance apart of the long,
projecting, spindle-shaped and furrowed
ridges which mark the stems, and in the
presence or absence of enlarged nodes
marked with whorls of tubercles. This
last difference may be specific, and ap-
FIG. 3. Portion of stem pears to correspond with certain differ-
drSly MnS ences in the structure of the wood.

Several of the specimens showing structure, represent the
pith-cylinder alone in a silicified state, and these specimens
have the external markings as perfectly shown as in the
sandstone casts, so that the supposed external markings of
Tylodendron may in some cases belong to the outer surface
of the pith-cylinders. The internal structure of these medul-
lary cylinders shows, in some cases, the transverse dia-

11

phragms characteristic of Sternbergia. In other examples
this is less pronounced or absent. The pith is composed of
ordinary parenchymatous tissue, becoming more dense
toward the outer surface, and especially in the prominences
corresponding to the exterior ridges. In each of these there
is also a vacant canal, and similar canals appear in a verti-
cal position in the interior of the pith, as if there had been
vessels dispersed through the pith and sending off bundles
to the exterior prominences. In some specimens, shreds of
woody tissue appear at the surface of the pith, and in
others, in which the pith is not preserved, the woody cylin-
der shows its character somewhat perfectly. In the cross
section it presents square meshes in radiating rows, not dis-
tinguishable from those of Dadoxylon. In the longitudi-
nal section, however, the tissue is seen to be thin-walled,
with very indistinct disks, which so far as observed, appear
to be in a single row, in which respect they differ some-
what from those observed by Weiss, which varied from one
to three rows, and with frequent medullary rays, simple
and composed of few cells superimposed, in which respect,
as well as in the disks, they differ
from those of Dadoxylon materi-
arium the species found with them
in the Permian sandstones of
Prince Edward Island. In the
nodose specimens, the woody fibres
are very small, and in the nodes,
become tortuous and interlaced in
the manner described by William-
son in the nodes of Calamites. In
the non-nodose form the tissue is
more open and very thin-walled.
Nothing is known of the structure
of the outer bark except impres-
sions of its form with elongated
leaf-bases different from the mark-
ings on the internal surfaces.
(Fig. 4.) With reference to the latter it would seem that they

FIG. 4. Leaf-base and outer
surface of Tylodendron
with fruit scars. (Drawn
by Mr. Bain.)

12

are not limited to the surface of the pith, but occur on the
woody cylinder as well. Mr. Bain has observed in one
instance, what seems to be an outer envelope which would
indicate a thick bark, but its structures are crystalline,
and it may be merely a concretionary covering.

The leaves and branchlets in fig. 5 have been found
by Mr. Bain in such relation to the debris of Tylodendron,
that he regards them as belonging to it. They certainly
differ from those of any of the known species of Walchia,

FIG. 5. Leafy ^branch of Tylodendron and leaf enlarged t
(Drawn by Mr. Bain.)

13

and more resemble those of the genus Voltzia. They
have apparently three nerves, but the lateral ones may
be resin-vessels.

Mr. Bain also finds at St. Peter's Island, with the bran-
ches and leaves of Tylodendron, the fruits or seeds represen-
ted in Fig. 6. They appear to be wedge-shaped and in
fours, and an involucre similar to that in Fig. C. accompa-
nies them, and is supposed to have oelonged to them, or
possibly to male flowers of the same species. Neither of
these organs have been found actually attached to the bran-
ches. If these fruits belong to Tylodendron they would in-
dicate taxine affinities, and they somewhat resemble the
curious coniferous fruits from the Tertiary of Australia
known as Spondylostrobus.

FIG. 6. Fruit and bracts of Tylodendron. (a) Fruit-
(6) single seed, (c) bracts. (Drawn by Mr. Bain.)

Stems having the markings of Tylodendron occur in the
Permo-Carboniferous of Cape John in Nova Scotia, and at
that place there are also obscure Yoltzia-like leaves some-
what resembling those of the Prince Edward Island
specimens.

If we connect the trunks, branches, leaves and fruits
above referred to, we can now extend the description given
by Weiss much beyond that given to his T. speciosum, and
should perhaps give a new name to the form from Prince
Edward Island, more especially as it differs slightly
both in markings and structure from that described by
Weiss.

TYLODENDRON BAINI, S.N.

Exterior of stem with elongated leaf-bases, truncate above,
obtusely pointed below. Pith-cylinder and ligneous surface

14

with elongate ridges pointed below and bifurcate above,
differing in size and form on branches of different sizes.
Branches or younger stems with nodes bearing a
whorl of prominences projecting beyond the general sur-
face.

Stem consisting of a pith-cylinder somewhat Sternbergian
in structure, and formed of cellular tissue denser at the
surface and with traces of detached vascular bundles.
Woody cylinder with fibres having one row of pores
and frequent medullary rays of few rows of cells superim-
posed.

Foliage borne spirally on pinnate (?) branchlets. Leaves
elongate, oblong, acutely pointed, narrowed and decurrent
at base, with a midrib and two side nerves, possibly resin
ducts. Fruit borne laterally on the branches, and consist-
ing of four large seeds, rounded without, and wec^ge-shaped
within, so that in outline they have a semi lunar form.
They seem to have been enclosed in an involucre.

Should it prove that the nodose and non-nodose stems are
specifically distinct, and that the leaves and fruit above
described belong to the latter, the description of the stem
will require a slight modification in that sense.

It would appear that in Tylodendron we have a gymno-
spermous type akin to the Taxinese, and which was charac-
teristic of the Permian, apparently extending also into the
Triassic Period.

We may now turn to the consideration of what is known
of Palaeozoic gymnosperms allied to the forms above
noticed, with the view of ascertaining their position in the
classification, and clearing up some doubtful points arising
from the fragmentary condition of our materials.

In the first part of the " Flore du Monde Primitif " (1820)
Sternberg describes and figures, under the names Flabellaria
borassifolia and F. palmata, two groups of leaves from the
Coal Formation, both apparently referable to the species
now known as Cordaites borassifolia. Leaves of this kind
have since been found very abundantly in the Carboniferous

15

in different parts of the world. To separate these plants
from others of different type, Unger proposed the name of
Cordaites, in honour of Corda, who had for the first time
figured a somewhat perfect leafy branch (Beitrage 1845) .
Corda's specimen showed something of the structure of the
stem which was described by him as having a ring of scalari-
form vessels surrounding a cellular pith, having that trans-
versely marked surface known as Sternbergia, indicating
diaphragms or partitions within. This apparently simple
acrogenous structure induced both Unger and myself to re-
gard the plant as allied to Lycopods, and it was placed with
these in my Acadian Geology, and in my paper on the
Fossil Plants of the Coal Formation of Nova Scotia.1 It
now appears, however, that Corda's figure must have repre-
sented only the inner ligneous zone, and this imper-
fectly.

The leaves in Sternberg's and Corda's specimens were
large, parallel-sided and pointed, with closely placed paral-
lel veins of two orders, and they were attached by a broad
base to the stem. The leaves showed bundles of fibres in the
veins and stomata in the epidermis.

Brongniart having the same objections with Unger to the
name of Flabellaria, but acting independently, in 1849 desig-
nated the leaves of Cordaites by the name PycTmophyllum,
but was induced by their peculiar form and structure to in-
clude them in the Gymnosperms with the allied family of
N&ggcrathiff, and near to the Cycads.2 He compares the
leaves with those of Dammara and Podocarpus among the
Conifers. Goldenberg and Weiss subsequently corroborated
Brongniart's view by the discovery of spikes of fructification
known as Antholites in association with Cordaites. Finally
Grand 'Eury discovered in the coal field of St. Etienne in
France, abundant and well preserved stems, leaves and
fruits which have enabled the French palseo- botanists to re-
construct the whole plant and to discriminate several gen-
era and species, constituting a gymnospermous family

1 Journal of Geological Society.

2 Tableaux de Genres.

16

which they designate Cordaitece, and which they regard as
intermediate between Cycadeos and Taxinece.

As restored on the basis of the French specimens, the typ-
ical Cordaites are simple or branching arboreal plants with
broad parallel-veined, more or less pointed, leaves attached
by a wide base to the stem, and leaving simple transverse
scars when removed. They bear spikes of nutlets, or large,
naked seeds, each subtended by a bract, and which are
usually lateral, though sometimes terminal. The stem has
a thick bark, composed of cellular tissue with bundles of
bast fibres, and the axis has an outer cylinder of porous tis-
sue, in wedges, with medullary rays, and an inner cylinder
of the slit-pored or transversely barred tissue, which I have
in previous papers designated by the term pseudo-scalari-
form, to distinguish it from the true scalariform-tissue, from
which it differs in having bars and pores only on two sides,
and in the apparent pores being of the nature of transverse-
ly elongated discs. It is very common in palaeozoic gym-
nosperms and exists in modern cycads. The pith is cellu-
lar with denser tabulae opposite the nodes of the stem giving
it the characters of the casts of pith known as Sternbergia or
Artisid.

Leaves of Cordaites, spikes of fructification known as
Antholites, now often called Cordaianthus, fruits of the kind
formerly known as Cardiocarpwn, but now usually named
Cordaicarpum, occur somewhat plentifully from the Middle
Brian to the Permian. If however, we are to regard, all the
Cardiocarpa as seeds of Cordaites, it seems remarkable that
the species of these fruits should be so numerous in compari-
son with those of the leaves and stems. In the Middle Erian
of New Brunswick, I have recognised five species of Cardio-
carpum, besides Antholites and Trigonacarpa, and in the Car
boniferous of Nova Scotia, the disproportion, as compared
with stems and leaves, is still very great. This might per-
haps lead to the inference that many of the species of Cor-
daites belonged to the nigher grounds, and that only water-
borne seeds found their way into the aqueous deposits. This
would also serve to account for the fact that while leaves of

Cordaites are locally very abundant, they are not so gener-
ally diffused geographically as the Sigillaria and Le-
pidodendra. The oldest species known to me is G. Robbii
from the Middle Erian of New Brunswick, where it occurs
with two species of Antholites — A. devonicus and A. floridus,
— perhaps its male and female flowers, and with the species
of Cardiocarpa already mentioned. I observe it has been
stated that C. Robbii has been found in the Upper Silurian
of Hainault.1 The latest species known in Acadia is
C. Simplex found in the Permian of Prince Edward Island
and also in the newer Coal formation of Nova Scotia.
Antholites and Trigonocarpa are found in the same beds, but
no Cardiocarpa.

Stems of Cordaites showing structure have not yet been
certainly recognised in this country. This leads, however,
to the question whether such stems may not have been
referred to other plants. I may mention more particularly
those named Dadoxylon, (Araucarioxylon) and Sigil-
laria.

With a view of settling this question, I obtained through
the kindness of the eminent French palaBobotanist, M.
Renault, specimens of the stems from St. Etienne referred
by him to Cordaites. These I found to be of two types which
may be distinguished as follows : —

(a) Silicified stem, associated with leaves of Cordaites
proper (C. borassifolia or allied). This has a large cellular
pith, which has, however, mostly disappeared, leaving a
hollow cylinder occupied with structureless silica and vege-
table debris. The pith has been nearly an inch in diameter
and showed no distinct evidence of Sternbergia structure.
The woody cylinder surrounding the pith was less than a
quarter of an inch in thickness, and consisted of two layers.
The inner of no great thickness, shows pseudo-scalariform
tissue, while the outer layer, which is radially arranged, is
composed of porous woody tissue, the pores or discs being
sometimes in one row, and sometimes as many as three

1 Ward, History of Palseo-botany.

9

18

rows, but not contiguous. There are medullary rays which
are numerous, simple and of few tiers of cells superimposed.
The cortical tissues have perished.

(b) The other stem is of smaller diameter with a strongly
marked Sternbergia pith, an inner layer of indistinct
pseudo-scalariform or spiral tissue and an outer layer,
much thicker in proportion, and with wood-cells having
three rows of contiguous hexagonal areoles with central
slit pores. The medullary rays are simple. This second
stem is not distinguishable from Dadoxylon of the type of
D. Brandlingii or D. materiariwn. The specimen itself
shows no evidence that it belongs to Cordaites.

Setting aside, as probably Coniferous, the second specimen
and assuming the stem (a) to be truly Cordaitean, it
accords with one of the species of Dadoxylon described by
me from the Erian of New York, namely D. Clarkii, which
presents similar characters though with a somewhat thicker
woody cylinder.1 D. Clarkii was described as follows in
1882.

" The pith cylinder is large and shows ordinary cellular
tissue. The medullary sheath or inner fibrous layer consists
of pseudo-scalariform and reticulated fibres ; but the most
remarkable feature of this wood is the structure of the
medullary rays, which are very frequent, but short and
simple, sometimes having as few as four cells superimposed.
This is a character not before observed in coniferous trees
of so great age, and allies this Middle Erian form with
some Carboniferous woods which have been supposed to be-
long to Cordaites or Sigillaria."

The resemblance of this peculiar stem to those of Cordaites
and Tylodendron, above referred to is obvious.

I have noted and illustrated by characteristic examples,
the fact that the erect ribbed trees found in the coal forma-
tion section at the South Joggins in Nova Scotia, often con-
tain the remains of their axis, either calcified and standing
erect within the tree, or fallen to the bottom in the form of
mineral charcoal. The examination of a large number of

1 Report on Erian Plants of Canada, Part II, 1882.

19

such axes has led me to the conclusion that there are two
types of these erect trees, one with an axis of scalariform
tissue only,1 though with the outer radiating cylinder
characteristic of Diploxylon, the other with a double axis
of pseudo-scalariform tissue internally, and discigerous or
multiporous tissue externally, of similar character to the
stems of Gordaitece. Perhaps in accordance with this is the
fact which I have also illustrated, that some so called
Sigillarice or Favularice of the type of S. Elegans, have some-
what broad parallel-veined leaves resembling those of Poa-
cordaites.2

As characteristic examples of these trunks, I may refer
to two which I have described in the Journal of the Geo-
logical Society.

(a) SIGILLARIA (Diploxylon.)

The most characteristic example is a trunk rooted in an
under-clay in the Joggins section and existing as a sand
cast 12 feet in height. This tree was discovered and care-
fully removed by Mr. Albert J. Hill, who found the interior
of the cast a calcified axis extending throughout its length
and showing well preserved structure. The structure is
described as follows : — 3

" The axis is about 6 centimetres in its greatest diameter,
and consists of a central pith cylinder and two concentric
coats of scalariform tissue. The pith cylinder is replaced
by sandstone, and is about one centimetre in diameter.
The inner cylinder of scalariform tissue is perfectly contin-
uous, not radiated, and about one millimetre in thickness.
Its vessels are somewhat crushed, but have been of large
diameter. Its outer surface, which readily separates from
that of the outer cylinder, is striated longitudinally. The
outer cylinder, which constitutes by much the largest
part of the whole, is also composed of scalariform tissue ;

1 Journal Geological Society of London.

2 Acadian Geology.

3 Journal Geological Society of London, Vol. xxxiii., 1877- ,

20

but this is radially arranged, with the individual cells
quadrangular in cross-section. The cross-bars are similar
on all the sides, and usually simple and straight, but some-
times branching or slightly reticulated. The wall inter-
vening between the bars has extremely delicate longitudi-
nal waving lines of ligneous lining, in the manner first de-
scribed by Williamson,1 as occurring in the scalariforn tissue
of certain Lepidodendra. (Fig. 4.) A few small radiating
spaces, partially occupied with pyrites, obscurely represent
the medullary rays, which must have been very feebly
developed. The radiating bundles passing to the leaves run
nearly horizontally ; but their structure is very imperfectly
preserved. The stem being old and probably long deprived
of its leaves, they may have been partially disorganized
before it was fossilized. The outer surface of the axis is
striated longitudinally, and in some places marked with
impressions of tortuous fibres, apparently those of the
inner bark. In the cross-section, where weathered, it shows
concentric rings ; but under the microscope these appear
rather as bands of compressed tissue than as proper lines of
growth. They are about twenty in number. Though
apparently of very lax tissue, the wood of the outer cylinder
may, in consequence of the strength of the vertical rods and
transverse bars of ligneous lining, have been of considerable
firmness, which would indeed seem to have been implied in
the manner of its preservation within the hollow bark."

This stem is evidently that of a Sigillaria of the Diploxylon
type, with a slender woody axis wholly of scalariform
tissue and a thick inner bark, probably mostly of cellular
tissue of a lax and easily decomposed character, but pro-
bably also with bundles of fibres. This was protected and
strengthened externally by an outer bark of sclerenchy-
matous cells, now converted into coal.

1 Monthly Microscopical Journal, August, 1860.

21

(6) SIGILLARTA (Favularia ?)

This example was furnished by another erect tree, about
a foot in diameter, and which I took down with care and
examined its contents. It was described and figured in the
journal of the Geological Society of London.1 Jt presented
the following parts: —

(a.) A coaly outer bark, no doubt originally composed
of dense sclerenchyma.

(6.) A cylinder of sandstone, representing the inner bark
entirely removed by decay.

(c.) A ligneous axis composed of wood cells, the inner
with two rows of contiguous bordered pores on their radial
surfaces, the outer with only one. The medullary rays
short, frequent, and of one row of cells or sometimes partly
with two rows. Diagonal bundles of pseudo-scalariform
tissue traversed this cylinder, no doubt leading to the
leaves.

(<?.) An inner cylinder of pseudo-scalariform tissue
similar to that in the inner cylinder of the axis in Cordaites
and in Cycads.

(0.) A medulla or pith, consisting of a hollow cylinder of
cellular tissue sending off at intervals thin diaphragms
toward the interior, giving it a Sternbergia structure.

This type of Sigillarian stem is obviously of far higher
grade than the former, and would justify the inference that
it belonged to a gymnospermous plant. The structures of the
stem correspond with that of others in which the axis exists
only as fragments in the base of the once hollow stump.
Some of these, however, conform to the type of multiporous
wood-cell seen in Poroxylon. If the foliage was like that
of Sigillaria elegans, and the spikes of fructification of the
nature of Antholithes, these parts might be referred to Oor-
daitece, though the stem was ribbed in the manner of
Sigillaria. I may add here that I have shown2 that some
Sigillarm of the Favularia type, divided at top into small

1 Vols. xxvi. and xxvii., 1870 and 1871.

2 Journal Geological Society, Vol. xxii., also Acadian Geology.

22

branches without ribs and with leaf scars very different in
form from those of the trunk.

The question now arises whether these different trunks
can belong to one genus, or even to one family ; whether,
in short, we may not have been confounding very different
types, of trees under the name of Sigillarice f The first of
the above types, that of Diploxylon, corresponds with the
structure of undoubted Sigillarice, as illustrated by William-
son and other British palseobotanists, and conforms so
closely to that of Lepidodendron that we can scarcely doubt
the close affinity of this particular type with the Lycopo-
diaceous Acrogens.

On the other hand, so many of the erect ribbed trees at
the South Joggins have afforded tissues of a much higher
type that we cannot doubt the existence there of trees simi-
lar in external characters to the ordinary Sigillarice., yet
with internal structures conforming rather to the type of
Cordaitece. In these circumstances, while we must admit
the Gymnospermous affinities of the latter family, we must
wait for further information before being able to define its
precise relations to the Sigillarise on the one hand, and the
Conifers on the other.

I have referred above to Sternbergia piths. These are
usually sandstone casts, but in some instances shreds of
the enveloping tissues remain. In a few instances the in-
ternal structure is preserved. Where the latter occurs it is
seen to be cellular, arranged in tubulse in the manner
which I have explained as occurring in the young pith of
the Balsam Fir and in the stem of Cecropia peltata. Such
piths I have described as occurring in large and well pre-
served stems of Dadoxylon of different species from the
Middle Devonian to the Permian. The large size of the
pith would seem to indicate that the young branches were
very thick, in which case they could not have resembled
those of Walchia or Araucarites, which other wise might be
supposed to represent the foliage of these trees, unless, in-
deed, there were thick branches bearing slender branchlets,
or unless, as Williamson has affirmed to have been the case

23

in some other Coniferous trees, the pith increased in size
with the growth of the stem or branch. There are, how-
ever, Sternbergiae which have not belonged to Dadoxylon.
I have figured1 specimens which show, attached to them,
multiporous tissue like that of Poroxylon or Dictyoxylon.
Others are enveloped with scalariform tissue like that of
Lepidodendron or Lepidofloios. This fact was long ago ob-
served by Corda. Others show pseudo-scalar! form and
discigerous tissue like those of Cordaites, or of the peculiar
type of supposed Sigillaroid trees above referred to. Thus
it is apparent that the Sternbergia piths belonged to a num-
ber of trees ranging from Gymnosperms of high type to
Acrogens. I may remark here that the true Calamodendra,
of which Calamites approximates is a type, in so far as the
medullary cylinder is concerned, are really internal casts of
pith cavities, originally surrounded by a thick woody en-
velope showing psuedo-scalariform and discigerous tissue,
and, therefore, not very dissimilar from that of Cordaites.
Williamson has shown, however, that the medullary rays
and other structures were diiferent, and the stems of
Calamodendra were jointed in relation to the support of
whorls of organs. If these Calamodendra were really
Acrogens allied to Catamites, they present the same curious
resemblance to Gymnosperms which we see in another form
in one of the types of Sigillaria, and warn us that the
structures of stems and the character of fructification may
not have been correlated in the Carboniferous in the same
manner as in modern stems.

Doubts of this kind are further justified by the considera-
tion of the stems known as Poroxylon, Medullosa, Cycadeo-
xylon, Colpoxylon, Lyginodendron, Kaloxylon and Heterangiwn,
several of which have recently been described in great
detail by Williamson and by Renault These have a true
medulla, surrounded by a cylinder of discigerous or reticu-
lated tissue, arranged radially and traversed by medullary
rays. Such characteristics would well suit a gymnosper-

1 Journal Geol. Society, 1871.

24

mous standing, but, on the other hand, there are specimens
which, as Williamson has shown, unite such structures
with foliage referred to ferns of the genus Sphenopteris.1
Williamson suggests that inasmuch as the living Stangeria
among the Cycads combines an exogenous stem with fern-
like leaves, the same may have been the case in the Carboni-
ferous. If so, the problem as to their position can be
determined in each case only by the discovery of their
fructification.

In Bertrand and Renault's recent elaborate memoir on
Poroxylon, these botanists have shown that this genus pos-
sesses an exogenous stem of some complexity. It has a
distinct pith, not Sternbergian, with gum canals, an inner
or centripetal layer at first in distinct bundles of scalari-
form and punctated fibres, a true radiating woody zone of
multiporous fibres, with numerous medullary rays, and a
cambium layer, two layers of inner bark, and an outer
suberous bark. The leaves are petiolate and simple, and
have a single vascular bundle at base, forking in the blade,
in the manner of Nceggerathia. From these and other
more minute characters in the distribution of the tissues,
the authors conclude that Poroxylon may be placed between
the Dyploxyloid Sigillarice and the Cycads, as probably a
low Gymnospermous type. They refer to three species of
Poroxylon — P. Edvardsti, P. Boyseti and P. Stephanensis.

Medullosa of Cotta presents several thick woody cylinders
twisted together, and with detached star-shaped or radiat-
ing bundles of fibres in the pith. The woody tissue of
Medullosa is said to resemble that of Palceoxylon, which is,
however, a subgenus of Dadoxylon, and allied to the
Conifers.

Colpoxylon has a thin woody cylinder and much thicker
bark than the preceding, and simple bundles in the pith.

Gycadeoxylon has several concentric circles of fibrous
tissue, with cellular tissue between them, somewhat in the
manner of Gnetacese, and with no fibrous bundles in the

1 Transactions Royal Society.

25

pith. My Dadoxylon annulatum shows structures approach-
ing to this last.

Eenault has constituted a new genus (May, 1889) under
the name Ptychoxylon, in which the wedges of the woody
cylinder extended inwards, and are then bent so as to simu-
late internal woody layers.

All these stems are regarded as probably gymnospermous,
and with the different types of Dadoxylon, the Cordaites and
Tylodendron, serve to give some account of the trees from
which the multiform nutlets and seeds of the Carboniferous
and Erian were derived.

The genus Nosggerathia, like that of Flabellaria (Cor-
daites), dates from the time of Sternberg, and his N.foliosa
is the original type, to which, however, a somewhat miscel-
laneous group of species has been added by subsequent
authors. Some of these, instead of the pinnate leaves of
the original species, have simple leaves spirally arranged
and decurrent on the stem. This is the case, for example,
with N.flabellata of Lindley and Hutton, which, on this
and other grounds, has been placed with some other
species by Schimper ] in a new genus Psygmophyllum, while
Saporta2 places them in his genus Ginkgophyllum, suppos-
ing them to be akin to the modern Ginkgo or Salisburia.

These two types of Noeggerathse agree with one another,
and differ from Cordaites in the flabellate form and forking
venation of the leaves. The nearest approach to the Cor-
daites is that of the leaf of JV. flabellata to that of C. patulus
Grand Eury.3 Saporta states that the ordinary Noeggera-
thiaB (N. foliosa) bear their fructification on the surface of
modified leaves, and he is inclined to place them near to the
Cycads. On the other hand, he regards the second typo
(N.flabellata, &c.~) as more nearly allied to the taxine Coni-
fers, though their fructification is not certainly known.
Lacoe's specimen, now under consideration, would, how-

1 Palseontologie Vegetale.

2 Evolution de Monde Vegetal

3 Saporta I. c.

26

ever, go to show that a plant with Noeggerathoid leaves
might have a fructification similar to that of Oordaites.

It has further become a question with palseobotanists to
what extent some of the broad, flabellate and rounded leaves
referred to Cyclopteris and other genera of ferns, may belong
to gymnospermous plants of the nature of Noeggerathia.
Of these leaves those already referred to of the genus Doler-
ophyllum seem certainly to be Gymnospermous. The pecu-
liar fan-shaped leaves described by Newberry under the
name Whittleseya,1 and of which one species occurs in the
coal formation of Nova Scotia, belong apparently to the
same category. The singular unilateral leaves, or fronds,
of which my Naggerathia dispar from Nova Scotia was the
type, and which Fontaine has recently separated in his
genus Saportea* may also be gymnospermous. Less cer-
tain is the reference by Saporta to this group of the genus
Cannophyllites of Brongniart, and of the large and beautiful
Erian and Lower Carboniferous fronds of my genus Mega-
lopteris.3 »

I have already referred to the numerous Gymnospermous
seeds known in the Palaeozoic, and belonging to the genera
Trigonocarpum, Cardiocarpum, Rhabdocarpus, etc.

The structure of many of these has been illustrated by
Hooker, C. Brongniart, Williamson and myself, and they are
unquestionably allied to the seeds of Oycadece and Taocinece.
When the vast abundance of these seeds on certain beds is
considered, and the fact that Schimper catalogues 67 species,
while recent discoveries would nearly double that number,
it becomes evident that plants of this grade must have borne
a very important part in the palaeozoic vegetation, and we
have reason to suspect that many stems and leaves now of
uncertain affinities will be found to have been of this class.

We may now tabulate as follows the principal Gymnos-
permous groups which may be represented in the Palaeo-
zoic : —

1 Lesquereux " Coal Flora."

2 " Permian Flora."

3 " Evolution du Monde Vegetal.

27

1. Sigillarife and Calamodendrese.

Favularia, (in part)?
Sigillaria proper, (in part)?
Calamodendron, (in part) ?

2. Cycadese.

Rhiptozamites. *

3. Nceggerathiss.

Noeggerathia.

Poroxylon.

Dolerophyllum.

Whittleseya.

Saportea.

Medullosa?

Colpoxylon ?

Ptychoxylon.

4. Cordaitese.

Dictyocordaites.
Cordaites.
Dorycordaites.
Poacordaites.

5. Taxinex.

Psygmophyllum.
Baiera ? 1
Ginkgophyllum.
Tylodendron.
Walchia, Voltzia, etc.
Dadoxylon.

6. Conifers.

It would thus appear :

1. That the nearest structural affinities of the Palaeozoic
gymnosperms with the higher Cryptogams lead toward all
the groups of Acrogens, viz. : Sigillariae, Calamitese, Lepi-
dodendrese and Ferns.

2. That the present dominant groups of Coniferse proper
and Cycadacese are absent or slenderly represented in the
Palaeozoic.

3. That the dominant Palaeozoic families are Ihe Noegge-
rathiae, Cordaitese and Taxineae, and that these occupied
a prominent and important place, and culminated in the
Palaeozoic and early Mesozoic periods.

1 Permian •, of Russia, Schmalhausen.

28

4. The two former families, did they now exist, would
supply connecting links between the Coniferse and Cycadese,
and between the latter and the Acrogens.

NOTE TO PAGE 13, SECOND PARAGRAPH.

With reference to the supposed fruit of Tylodendron, a comparison
may also be suggested with the Eocene fossil fruits from the
London clay, of the genus Selenostrobus, and with the modern genus
Calliiris. In these, however, the fruit presents a verticil of valves en-
closing seeds, rather than of naked seeds. In the case of Tylodendron,
however, there may have been deciduous scales. The number
four apppers in some species of Cattitris. It is five in Selenostrobus
and Spondylostrobus. This subject has been discussed, with refer-
ence to the Tertiary and modern fruits, by Bowerbank, Endlicher,
Heer, Schimper and Von Mueller.

ADDITIONAL NOTE

Since writing the description of Dictyocordaites Lacoi, I have seen
Nothorst's paper on Dictyozamites of Oldham, a Cycadean genus
with netted venation which occurs in the Mesozoic formations of
Japan, India and Sweden.

FRONTISPIECE.

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