FOSSIL PLANTS. 
389 
the axillar pinnules, still larger and cyclopteroidal in form, are 
attached around the stem by a half circular notch, nearly sur¬ 
rounded by two broad auricles. The veins, anastomosing from 
the base without medial nerve and in their undulations form¬ 
ing oval-polygonal elongated meshes, curve towards the bor¬ 
ders, where the last divisions end in arched close lines. 
In this species, found.in soft shales at Murphysborough, the epidermis or 
substance of the leaflets has become, by maceration, separable from the stone, 
and is easily obtained in lamellae. Whole pinnules can be got in that way 
without any earthy substance adhering to them; and in that semi-opaque state 
their texture and nervation are easily studied with the glass. The veins pre¬ 
sent, under the microscope, the appearance marked in fig. 2. 
When the 2d vol. of this Report was published, no species of this genus had 
been found in Illinois. Now this new one, obtained in numerous and well 
preserved specimens, not only adds a beautiful species to the flora of the Coal 
Measures, hut furnishes us new evidence on some questions concerning the vege¬ 
tation of plants of this kind. First, our specimens prove, beyond doubt, the 
close relation of this genus with the former. The form of the fronds, of the 
pinnaae, of the leaflets, and their variety in size and shape, are exactly alike in 
both genera. Truly but for its nervation, we should have in our new Dicfyop- 
teris a Neuropteris scarcely distinguishable from Neuropteris Loschii, or Neu- 
ropteris tenuifolia. But further, the peculiar nervation, as well as the peculiar 
reddish color of the plant in its fossil state, permit us to identify the large 
leaflets of the species of this genus with the small ones, or afford the proof that 
for Dictyopteris as for Neuropteris, the large round cyclopteroidal pinnules, 
always found isolated, really belong to species represented by pinnae bearing 
small leaflets of a widely different form. It would not certainly be possible to 
admit specific identity between the leaves represented, pi. vii, fig. 2, and those 
of fig. 5, without those peculiarities of structure remarked in both. 
The species of Dictyopteris are rare in the Coal Moasures. In the United 
States none had as yet been found but D. obliqua , Bunb., whose remains are very 
abundant at some places in Pennsylvania and Ohio, and which have also been 
found, but rarely, in Kentucky and Arkansas. By the form of its leaflets, its 
ramification f c. f, this last species is related to Dictyopteris Brongncirti, Gutb., 
the only species of this genus known in the Coal Measures of Europe. For 
D. neuropteroides, Gutb., described from a few small leaflets, is, according to 
Prof. Ellinghausen, a true Neuropteris , and Dictyopteris cordata, Roem., ac¬ 
cording to the remarks of the author himself, is a variety of Neuropteris cor¬ 
data Brgt., as his D. Hoffmanni seems to be a variety of D. Brongnarti, Gutb. 
