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1

2

3

1

2

3

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5

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[From t

Art. I.

I HAV:

of Pittst.

specimer

nian) at

promises

fossil bot

to the Di

a prelimi

will requ

done in (

berg to tl

hope will

specimen

which ne

The 8f

and 46''=»

shows, UT

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[From the American Journal op Science, Vol. XXXVTII, July, 1889. |

Art. I. — A new Erian {^Devonian) Plant allied to Cordaites y

by Sir Wm. Dawson. ,

I HAVE recently, through the kindness of R. D. Lacoe, Esq.,
of Pittston, Pa., had an opportunity to study a remarkably line
specimen collected by him in the lower Catskill (Upper Devo-
nian) at Meshoppen, Wyoming Co., Pennsylvania, and which
promises to throw much light on some difficult questions of
lossil botany, as well as to add a new and very interesting form
to the Devonian flora. The present note is intended as merely
a preliminary notice. The full discussion of this unique plant
will require a reference to much of the work that has been
done in Cordaites, Noeggerathia, etc., from the time of Stern-
berg to the recent reports of Lesquereux and Fontaine, and I '
hope will illustrate a number of fragmentary and enigmatical
specimens which have long been in my own collections, and
which need further study in connection with it.

The specimen is a branch or small stem 2^^*"° in diameter
and 46*"" in total length. It is flattened and pyritised, and
shows, under the microscope, merely the indications of a pith
surrounded by a fibrous envelope, the minute structure of
which is not very well preserved, but it is hoped by proper
treatment may give some further information. The stem shows
portions of about 15 leaves which have been at least IB*"" long
nd 3 to 4™ broad. They are decurrent, apparently by a broad
ase, on the stem. Their distal extremities are seen in a few
ases, but in all seem injured by mechanical abrasion or decay,
t see ms most probable that they were truncate and uneven at

• • • • e p

I

2 \V. Daivson — New Er'ian {Devonian) Plant

their extremities. The stem is terminated by a ehister or com-
pound corymb of spikes of wliich 20 are seen. They ai'e
slender, but seem to nave been stiff and woody, and the largest
are about 16™ in length. They have short pointed bracts, and
some of them bear oval fruits, but only a few of these remain,
the greater part of them having apparently fallen off before
the plant was fossilized. So far the characters do not differ

which I
genus
out to
Cordaii
ists bel
Cordaii
are neai
Eury in
name /
name L

It is
of the
thus coi
are now
entertai
into coi
which h
it will t]
Ganadia
Noeggeri
Lepidoa.
some sp
with eac

I hopi
will nec<
ray own
ing meet

1 may
Rohhii c
found in
is a some
rathia ai

EXPLA]

duced. (

from those of the genus Cmxiaites, except that in those plants the
spikes of fructification are more usually lateral than terminal. A
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 provisional genus Noiyyerathta, some of j

W. Dawson — ^ew Erian {Devonian) Plant.

3

which have this peculiarity, as also certain modern Cycads of the
genus Zamia, which Professor Penhallow has kindly pointed
out to me. The present plant would seem to be a form of
CordaitecBj tending to NcBggerathia^ which many paleobotan-
ists 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-cordaitea for the present genus, and the specific
name Laxsoi, in honor of its discoverer.

It is apparent that this specimen combines the fructification
of the VordaitecB with leaves akin to those of Nc&ggerathia^
thus connecting two groups of paleozoic plants, both of which
are now considered as allied to Cycadem and Taxine(B„ and I
entertain the hope that when it is fully studied and brought
into comparison with other specimens in my collections, or
which have been figured and described by other paleobotanists,
it will throw additional light on a great number of Paleozoic
Canadian leaves, fruits and stems, now designated as Cordaitea,
N (Bggerathia^ Psygmophyllum^ Oingkophyllum^ Siembergia,
Zepidoxylon, Saportea, etc. ; and which have been waiting for
some specimen thus complete to bring them into harmony
with each other.

I hope to be able to bring the whole of this material, which
will necessitatfc some change in the nomenclature of some of
my own species, under the notice of geologists at the approach-
ing meeting of the American Association.

1 may add that the oldest true Cordaites known to me is C.
Rohhii of the Middle Devonian, which is said to have also been
found in the Silurian. C. angustifoha of the Lower Devonian
is a somewhat uncertain species. Plants of the genus Nc&gge-
rathia are known in the Upper Devonian.

Explanation of piguue. — Dictyo-cordaites Lacoi^ much re-
duced, (a) Venation of leaf, natural size, {b) Fruit enlarged.

nts the
lal. A ■
which
g at a
anches
ies the
ome of I

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