﻿39° SMITHSONIAN MISCELLANEOUS COLLECTIONS [VOL. 47 



Rhabdoatrpos were, on the whole, hardly to be expected in view of 

 the typically filicoid habits of the fronds, the presence of distinctly 

 pteridophytic characters in the stems and petioles, and the antiquity 

 of the seed-bearing types. 



Since Lyginoptcris, C alamo pity s, and Protopitys are present in 

 rocks of Lower Carboniferous age, it follows that the heterosporous 

 filices, which must have antedated the Cycadofilices, are to be looked 

 for at the very base of the Carboniferous, if not, as is more probable, 

 in the Upper Devonian. Triphylloptcris, which the writer believes 

 to be Pteridospermic, occurs near the base of the Lower Carbonifer- 

 ous in America. Concerning the Pteridospermic nature of the 

 specimens reported as Kalymma grandis from the Black Shale of 

 Kentucky, there appears to be room for doubt. Should, however, 

 the interpretation of these fossils prove valid, the Cycadofilices will 

 go back to the Middle Devonian (Genessee), or nearly as far as the 

 oldest plant fossils generally recognized as unquestionably ferns. 

 The presence of gymnosperms at this early date is generally accepted 

 on the evidence of the occurrence of fossil woods representing sev- 

 eral species of Dadoxylon, which includes the trunks of Cordaites. 

 Some of these early species have, as has already been suggested, 

 very much in common with Protopitys. 



In a discussion of the recent discoveries relating to the Cycado- 

 filices, which he seems inclined to regard as gymnosperms, Professor 

 Zeiller remarks that it may become necessary to refer to the Carbon- 

 iferous as the epoch of the gymnosperms. rather than of the Crypto- 

 gams. Whatever the limits and final interpretations of the Cycado- 

 filices, they constitute a well-marked filicoid group preeminently 

 characteristic of the Carboniferous, which may appropriately be 

 paleobotanically designated as the epoch of the Pteridosperms — the 

 seed-bearing ferns. 



