FERNS— SPHENOPTEEIDEJE—SPHENOPTEKIS. Q I 



overlapping, parallel, lanceolate; tertiary pinna?, open, alternate, rigid, over- 

 lapping a little, lanceolate, or lanceolate-triangular, ratlier obtuse, with 

 stout, roughly striate rachis, which is shallowly canaliculate on the ventral 

 surface; ultimate pinna3 alternate, open, somewhat flexuous, nearly touch- 

 ing or slightly overlapping, rather dense, ovate-oblong or lanceolate, 

 obtuse, with irregular surface; pinnules alternate, when very small broadly 

 ovate, close, and decurrent, becoming confluent and obliterated toward tlie 

 top of the pinna, or, when larger, crenulate and cut in rounded or ovate, 

 decurrent, outward-curved lobes in the lower part, crenulate and ovate- 

 rounded above, the largest ones ovate-triangular, very obtuse and pinnatifid, 

 with a broad attachment sometimes slightly elongated to form a broad, very 

 short, decurrent footstalk with narrow borders decurring along the rachis; 

 lamina coriaceous, slightly furrowed over the primary nerve in the larger 

 pinnules, repand; nervation quite distinct, coarse, and usually slightly sal- 

 ient on the upper surface, giving the pinnule a very rough aspect; primary 

 nerve strong, originating obliquely, curving, often quite decurrently, flex- 

 uous, more or less distinctly subgeniculate in adaptation to the secondary 

 nerves at the bases of the lobes or crenulations ; secondary nerves, one for 

 each lobe or crenulation, given ofl" at a rather open angle, and forking once 

 or twice at a wide angle, all the divisions, especially the upper branches, 

 curving strongly outward, and each forking once or twice again, according 

 to the stage of the development of the lobe, the nerves of each lobe or 

 very small pinnule having a fasciculate appearance, and strongly arched 

 upward, the ultimate nervils passing parallel to the margin, which, in the 

 larger lobes, they reach at nearly a right angle to the midrib; fertile 

 pinnge very different from the sterile pinnae, in the lower or middle por- 

 tion of which they are probably borne; consisting primarily of oblong or 

 oblong-ovoid, more or less curved, fleshy pinnules about 8-12 mm. long 

 and 2-3 mm. in width, borne alternately and apparently sessile on a broad 

 rachis; sporangia fusiform, about 1.75 mm. long, and .75 mm. in width near 

 the base, tapering to an acute point, apparently an-anged pendent or some- 

 what inflexed in a close or crowded fringe about the margin of the fertile 

 pinnule. 



Among the specimens last transmitted by Dr. Britts from Clinton are 

 several fragments of sterile pinnae which, almost without doubt, belong to the 

 same plant as the fertile specimens described from the same beds nearly 



