184-5.] BUNBURY ON FOSSIL FERNS. 83 



specimens before me. In Goppert's figure, indeed, of Diplazites 

 emarginatus, some of the veinlets are represented as meeting each 

 other in the manner I have described, but in the description he 

 states that they all reach the margin of the frond. 



The fructification, which is very conspicuous in some of our 

 Frostburg specimens, has the appearance of small, crowded, roundish 

 spots (sori), placed with considerable regularity in double rows be- 

 tween the primary veins. Some of the pinnae are entirely covered 

 with it except at their extreme margins; on one it occupies the 

 upper part, from about the middle to within a short distance of the 

 extremity. 



As Goppert himself ascribes the confused manner in which the 

 fructification of his Diplazites emarginatus covers the frond, to its 

 advanced stage of maturity, it is very possible that, in an earlier 

 state, it might have been arranged in the same manner as in our 

 plant. In that case there would be no difference between them, 

 except, perhaps, in the angular confluence of the lower veinlets. I 

 say perhaps, because his own plate is at variance with his descrip- 

 tion in that particular. The pinnae of our plant are not indeed 

 emarginate at their extremities, but neither are they represented so 

 in his figure. 



The Pecopteris longifolia of Brongniart (^Diplazites longifolius of 

 Goppert) differs from ours in its much narrower pinnae, as well as 

 in all its veinlets being free, and perpendicular to the margin. 



If now we compare our Frostburg fossil with recent ferns, we see 

 that the round sori remove it altogether from the group to which 

 Diplazium belongs, and would lead us to look for its affinities among 

 the Polypodece or Aspidece. The genera Goniopteris and Nephro- 

 dium (as limited by Presl) have a venation nearly resembling that 

 of our plant, except that the veinlets are less oblique ; in the former 

 genus there is a farther similarity in the arrangement of the sori, in 

 double rows between the primary veins. I do not, however, know 

 any species of either genus that comes sufficiently near, as a species, 

 to our plant, to be worth comparing with it. 



As the generic name Diplazites is thus shown to be inapplicable 

 to this fern, we must either give it a new generic name, expressive 

 of its apparent affinity with Goniopteris^ or place it in the large and 

 miscellaneous genus Pecopteris^ next to Brongniart's P. longifolia. 

 The latter m ill be, for the present, the safer plan, for much confu- 

 sion and error may be produced by hasty attempts to refer the fossil 

 ferns positively to recent genera ; and Pecopteris, though a hete- 

 rogeneous assemblage, at least possesses definite and intelligible 

 characters, which is more than can be said for most of the genera 

 that have been formed out of it. As it appears most probable that 

 the species is the same as Goppert's Diplazites emarginatus^ the 

 specific name (though not particularly appropriate) must be re- 

 tained, at least provisionally ; and it may stand as* 



* It might form a distinct section of the genus, to be called Goniopteridites, 



g2 



