1 12 THE POTOMAC OR YOUNGEE MESOZOIC FLORA. 



less deeply into subrhoinbic or broadly elliptical and rounded lobes ; 

 nerves numerous, closely placed, slender but distinct, repeatedly branching 

 in the lower lobes, and diverging flabellately ; midnerve in the terminal 

 lobe dissolving in branches some distance below the summit, and in its 

 lower portion sending off very obliquely nerve bundles or branches which 

 fork one or more times. 



Localities: Fredericksburg; road-side near Potomac Run ; very rare. 



This plant in some of its forms is something like T. yraniilata, but it 

 shows none of the granulations and the pinnules are more obtuse. 



Stenopteris Saporta. 



Frond large, bipinnatifid ; rachis slender and narrowly winged ; 

 pinnae subopposite ; segments of the pinna? long, linear, bluntly termi- 

 nated, showing the same width and structure as the parts to which they 

 are attached; that is, a slender, narrowly winged midnerve, segments some- 

 times forked at their, tips. This descripti )n given by Schimper' agrees 

 well with one of the Potomac species, and for this reason I place it pro- 

 visionally in Sa])orta's genus. 



Stenopteris Vieginica, sp. nov. 



Plate XXI, Fig. 8. 



Frond unknown ; lobes of the pinnules or pinnae of ultimate order, 

 forking at the ends or simple ; pinnules and lobes coriaceous, strap-shaped, 

 subacute, having a single slender nerve. 



Locality: 72d mile-post, near Brooke; I'are. 



This plant agrees with Saporta's genus Stenoi)teris, which contains, as 

 ^'AY as certainly made out, only the single species S. desmoinera. The 

 description, however, whicli makes the midnerve narrowly winged does not 

 apply, as the laminte on each side of that nerve in the Potomac plant are 

 comparatively wide. Only a single specimen was found at the Brooke 

 locality. 



' Zittel's Handbuch tier Palseoutologie, vol. 2, p. 111. 



