Lesquereux. ] 164 [Oct. 19, 
We have thus a sufficient reason for the publication of the following 
documents relative to the subject. 
DESCRIPTION OF SPECIES. 
Genus PSILOPHYTUM, Daws. 
Quat. Journ. of the Geol. Soc. of London, p. 478. 
“Lycopodiaceous plants, branching dichotomously and covered with in- 
terrupted ridges or closely appressed minute leaves; the stems, springing 
from a rhizome, having circular areoles sending forth cylindrical rootlets. 
Internal structure, an axis of scalariform vessels, surrounded by a.cylinder 
of parenchymatose cells and by an outer cortical cylinder of elongated 
woody cells (prosenchyma). Fructification probably in lateral masses pro- 
tected by leafy bracts.”’ 
The species which I have to describe here differs by these points only 
from the generic description : the stems of one of them has not any inter- 
rupted ridges or strie of any kind ; both are without leaves. But in the 
species described by the author the leaves are either rudimentary or, more 
generally, the stems are naked, either in their original growth or by denuda- 
tion, catised by maceration or other physical circumstances. For example, 
Psilophytum elegans and P. glabrum have no leaves; P. robustius, judg- 
ing from figure 121 in Dawson’s Precarboniferous plants of the Geologi- 
cal Survey of Canada, bears leaves at the extremity of the branches only, 
and the stems appear smooth as they are also in P. glabrum. 
PsILOPHYTUM GRACILLIMUM, Sp. Nov. 
_Pl. L, fig. 2. 
Stem very slender, dichotomously branching, smooth or naked half 
round, slightly channeled in the length ; branches numerous, of various 
length, filiform. 
The stem is scarcely one millimeter thick at the base ; the upper branches, 
curved as from a spiral unfolding, are slender, gradually attenuated and 
capilliform, or of the thickness of thin thread at their extremities. 
The plant embedded in hardened, blue, shaly clay or mar], is transformed 
into coal, part of the branches broken and displaced having left their prints 
as half cylindrical concave moulds. This character, as also the depression 
in the middle and along the whole axis, proves the woody or vascular 
texture of the plants and of course separates them from the Hucozds. 
Comparing this specimen with species published by Prof. Dawson from 
the Devonian measures of Canada, its relation to P. elegans, Quat. Journ. 
Geol. Soc., Nov. 1862, p. 315 Pl. xiv, fig 29, 30, is recognized as quite close. 
But the affinity of the characters is still more marked with a plant of 
Psilophytum as restored in its original state for exemplification of the 
genus in the Proceedings of the same Journal, Jan. 1859, p. 479, fig. i. If 
this figure, whose stem is without leaves, was the exact representative of a 
peculiar species I should have considered our silurian form as identical 
with that of Canada. 
