FOSSIL I-LANTS. 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, but 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 Dictyop- 

 teris a Neuropteris scarcely distinguishable from Neuropteris Loschii, or Neu- 

 ropteris tenui folia. 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 Measures. 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 Brongnarti, 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. 



