FERNS— SPHENOPTEBIDE.E—SPHEEOPTEEIS. 45 



Sphenopteris pinnatifida (Lx.). 

 PI. XVIII, Figs. 3, 4; PI. XIX, Fig. 1. 



18C0. Rymenojihyllites pinnatifidus Lesquereux, Kept. Geol. Surv. Illinois, vol. ii, p. 436, 



pi. xxxiv, flgs. 2, 2a. 

 1879. Sphenopteris (HymenophylUtes) tridactylites Brongn., Lesquereux, Coal Flora, 



Atlas, pi. iv, figs. 9, 9rt-i (figs. 8, 8rt. ?); text, vol. i (1880), p. 284 (pars). 



Fi-ouds polyi)iiinate, delicate, spreading; secondary (?) pinnae alternate, 

 close, linear-lanceolate, slightly contracted at the base, tapering to a rather 

 acute point; secondary rachis straight or slightly curving, somevs^hat sulcate 

 above, rounded beneath, minutely irregularly striate, naked; tertiary pinnte 

 alternate, nearly at a right angle to the superior rachis, nearly contiguous 

 or overlapping somev?hat, usually very slightly decurrent at the base, linear- 

 lanceolate, slightly narrowed at the base, tapering from belov? the middle 

 to an acute tip ; tertiary rachis slightly flexuous, minutely Mringed near the 

 apex; ultimate pinnae alternate, at a right angle to the rachis, or nearly so, 

 generally slightly distant, sometimes touching or overlapping a little, 8 mm. 

 to 20 mm. or more in length, lanceolate or lanceolate-triangular, sometimes 

 slightly decurrent, terminating in a single oval, obtusely pointed pinnule, and 

 provided with ovate, rounded-obtuse, alternate or subopposite, simple, bi-, 

 tri-, or many-lobed pinnules, the latter becoming 7 to S lobed and elongated 

 in passing into pinnae ; lobes or incipient pinnules obhque, decurring along 

 the rachis, more or less deeply divided, according to the degree of develop- 

 ment; limb dull, rather thin; nerves slightly flexuous, not very distinct, 

 forking pinnately to permit one nervil to enter each lobe; fructification 

 consisting of groups of crowded sporangia situated on the lobes of the pin- 

 nules and covering the stirface at or near the ends of the lobes; sporangia 

 ovoid, about .375 mm. in longer diameter, and about .3 mm. in the shorter 

 diameter, apparently composed of cells elongated in the direction of the 

 longer axis, and opening by an apical pore. 



It was only after an examination of the type specimen of Hymenopliyl- 

 liies pinnatifidus Lx., illustrated in the second volume of the Reports of the 

 Illinois Geological Survey,^ that it became evident to me that our Missouri 

 specimens belonged to this poorly delineated species, wliich was afterwards 



I PI. xxxiv, figs. 2, 2a. p. 436. 



