FERNS— SPHENOPTEKIDE^E—SPHliNOPTERIS. 37 



what withered or macerated pinnules are curled under and buried in the 

 matrix. The characters of the detail, fig. Iff, loc. cit, I have been unable 

 to confirm in the large specimen, while the rough rachis and the general 

 habit of the pinnae, which are quite inaccurately illustrated, are strongh- sug- 

 gestive of some specimens of Sphenopteris Brittsii Lx. found in the same beds. 

 No intermediate forms, such as might connect this specimen with the type 

 of Sphenopteris mixta, have, so far as I know, been found. On the contrary, 

 its characters would seem to indicate such a variation from the normal as 

 might be regarded as more than merel}^ varietal. 



The normal form of Sphenopteris mixta is well shown in Fig. 4, PI. 

 XITI, which represents a middle portion of the tripinnate frond. Fig. 1, 

 PI. XII, shows a lax lateral segment with large pinnules, and Fig. 2, PI. 

 XII, illustrates a part of a large pinna having the aspect of the figure given 

 in the Illinois report. 



Although this species is included by Potonie^ in the section of the 

 Sphenopterids for which lie created the genus Ovopteris, I am inclined 

 rather to regard it, on the evidence of its superficial characters, as related 

 to Sphenopteris quercifolia, S. microcarpa Lx., and the group represented in 

 S. Ha:ninghausii Brongn. 



Sphenopteris mixta, which in its habit and even in many details is close 

 to the specimen figured by Stur^ as Hapalopteris rotimdifolia (Andrli) Stur, 

 or to Sphenopteris Laurentii as figured and described by Andra^ and seen 

 by myself in British specimens, is easily distinguished from Sp)henopteris 

 Brittsii Lx. by the more robust habit, the spiny rachis not so flexuous, the 

 rougher lamina, and the sharp teeth of the latter. The differences between 

 it and S. Lacoei are noted in the remarks following the description of the 

 latter. 



Localities. — Owens's coal bank, U. S. Nat. Mus., 5713, 5714, 5524, 5527, 

 5531 ; Gilkerson's Ford, U. S. Nat. Mus., 5458 ; Deepwater, U. S. Nat. 

 Mus., 5692, 5521, 5522, 5529; Hobbs's coal bank, U. S. Nat. Mus., 5712, 

 5715, 6037, 5687, 5522, 5526, 5530. 



1 Potonie, Fl. Eothl. Thiiringen, 1893, p. 42. 



2 Fame d. Carbon-Fl., p. 33, pi. xliv, tigs. 3, 4. 



^Urweltl. Pii. Steinkohlengeb. Pr. Rheiul. u. Westphal., Pt. iii, 1869, p. 39, pi. xiii, figs. 1, 2, 3. 



