48 FLOKA OF LOWER COAL MEASUEES OF MISSOURL 



nearly parallel in the lower portion, and tapering from the middle upward, 

 with a slightlv flexuons, moderatel}' strong, shallowly canaliculate, 

 extremely narrowly bordered rachis; ultimate pinnae alternate, open nearly 

 at a right angle near the base, becoming somewhat oblique higher up, close, 

 touching or somewhat overlapping, oblong, triangular, obtuse or slightly 

 obtuse, somewhat rigid, nearly equilateral, constricted at the hardly decur- 

 rent base, the lower inferior pinna slightly elongated, and joined along the 

 rachis by a very narrow, often obscure, wing; pinnules or lobes very small, 

 aud delicately denticulate or cristate; when small, obovate, oval, or ovate, 

 and obtusely rounded above, cut into 2 to 6 short, rather broad aud acute 

 teeth, and attached b}' nearly the whole width, with a rather broad decur- 

 rent wing; when larger, about '2.5-3.5 mm. long and about 1.5-2.5 mm. 

 wide, becoming more deeply dissected in 5 or 6 lobes, the lower ones of 

 which already have each 2 or 3 teeth formed; lamina membranace- 

 ous, transparent; nervation very distinct; primar)' nerves of the pin- 

 nules or shorter ultimate pinnae rather strong, lineate, rigid near the base, 

 tapering in passing, slightly flexuous, to the summit; basal nerve of each 

 pinnule or lobe originating at a very open angle, seldom decurrent, and 

 forking pinnately at a wide angle, one straight or slightly upturned nervil 

 entering and passing to the apex of each tooth. 



The specimens to which I have given the above name represent one 

 of the most beautiful and delicate species I have yet seen from the Carbon- 

 iferous of this country. It is remarkable for the extremely delicate and 

 lace-like effect of its regular pinnae and transparent limb, traced in a pattern 

 of exquisite daintiness and intricacy. The plant is specially characterized 

 by the smallness and mode of dentition of the divisions and the tenuity of 

 the laminae. 



The general aspect of Sphenopteris van Ingeni is at once strikingly 

 suggestive of Sphenopteris Duhuissonis Brongn.,^ under which name it was 

 probably identified by Lesquereux from this region.^ Although there can 

 be no doubt that it is very closely related to and belongs in the same group 

 with Brongniart's plant, it differs from that species, as will be seen in Fig. 

 3, PI. XIII, and the enlarged detail, Fig. 3a, in the closer, much wider 

 pinnae, aud the more elongated, less constricted lobes or pinnules, which 



' Hist. veg. foss., pi. liv, figs. 4a, 4ft, p. 195. 

 ^Coal Flora, vol. iii, p. 880. 



