FOSSIL PLANTS. 
415 
which it is evidently attached, while Prof. Geinitz thinks that it is fixed in 
small bundles to the stem, like a parasitic plant. The State Cabinet at Spring- 
field possesses specimens of a large fern whose stem, like that described by 
Lindley, is bordered by bundles of leaves of the same Hymenophyllites. The 
specimen is obscure, and it is not possible to decide how they are attached to it. 
Hymenophyllites lactuca, Gutb. 
This species is more rarely found in our Coal Measures than its near rela¬ 
tive, 11. Clarhii. Lesqx. The State Cabinet has a very fine specimen of it in 
a concretion from Mazon creek. It is distinguished from II. Clarlcii by its 
broad enlarged fronds and narrow lacinite. These fronds or rather pinnte, on 
one side of the rachis, which are only visible in part, appear placed in a row,- 
like the alternate divisions of a fern. As the epidermis of some of these pin- 
nrn is destroyed by maceration, the veins and veinlets are distinct, and are seen 
passing in bundles from the rachis, separating more and more in curving into 
each division, to end by a simple veinlet, ascending to the point of the acute 
ultimate lobes. 
Hymenophyllites arborescens, Sp. nov. 
PI. xvii, fig. 1 . 
Stem long, (the specimen, though broken, shows more than 
one foot of it,) straight, about one inch broad at its lower end, 
two-thirds of an inch at its upper part, marked in its length 
by obscure lines apparently formed by bundles of veinlets and 
alternately divided in thick oblique branches, more or less 
regularly and deeply lobate; lobes alternate, simple and linear 
elongated, or bi-trifid, of various lengths and obtusely pointed. 
The divisions of this plant are rather dichotomous, like those of species of 
Lycopodiacea, than pinnatifid like those of ferns. They are merely a continu¬ 
ation of a main axis thrown out in various directions. The substance appears 
to have been a compound of cellular soft tissue, intermingled with bundles of 
continuous vessels, forming veins or veinlets, and, by mere separation, ascend¬ 
ing to the last divisions of the frond. There is no trace of branching of veins, 
