160 THE POTOMAC OK YOUNGEll MESOZOIC FLORA. 



ently from the racliis and forking near the base ; the branches, so far as 

 seen, simple, and nearly parallel. 



Locality : Fredericksburg ; only one specimen found. 



This is another of those curio us forms which, as they stand nearest to 

 Ctcnopteris, are placed provisionally in this genus. The obscurity about 

 the nerves is wholly confined to their character at the attachment of the 

 pinnules. They were not distinctly seen at this point, and may be not 

 forking there but separate. The plant is very much like the genus 

 Enceplialartos, and especially resembles E. tridentalns Lehm. It may really 

 belong to this genus. 



ZAMIOPSIS, gen. nov. 



Fronds large, bipinnate to tripinnatifid ; leaf-substance leathery and 

 thick, covered with a dense durable epidermis ; rachises strong, rigid, and 

 keeled on the lower surface, often with ri'dged or raised margins on the 

 upper surface ; penultimate pinnce very long, ultimate pinnae or pinnules 

 usually closely placed, narrowed to the base, mostly linear-lanceolate or 

 oblong-lanceolate, the lower ones generally cut obliquely into pinnules 

 which are denticulate, but pass above into denticulate or spinous teeth and 

 terminate in two or more spinous teeth; nerves of the pinnules and lobes 

 mostly composed of a midnerve which goes off very obliquely and curves 

 strongly outwards, sending off obliquely and alternately lateral branches, 

 which are forked or simple and curve upwards towards the summit of the 

 segment ; in the lobes and teeth the lateral nerves go off very obliquely 

 and fork once or twice, having very long ultimate branches ; nerves, 

 although fine, very distinct. 



This curious type of ferns, if ferns they are, reminds one of the 

 cycadean genus Stanr/eria in some respects, but in the nature of the lobes 

 and teeth they differ from Sfanf/crki. In most species the nerves towards 

 the upper portion of the ultimate pinnae or pinnules are very oblique and 

 have long slender branches, while in the lower or basal portions they form 

 nerve-bundles that curve more or less strongly outwards to meet the mar- 

 gin of the pinnule or I'educed pinna. The plants show a curious blending 

 of the features of cycads and ferns, with a predominance of the latter. 



