FERN S— TRIPH YLLOPTERIDE^— PSEUDOPECOPTERIS. 25 



1869. Sjihenopteris (Oymnogrammicles) irregtdaris Sterub., Scliimper, Traite, vol. i 

 p. 373. " ' 



1877. Diplothmema obtusilobum (Brougn.) Stur, Oulm-Flora, vol. ii, p. 124 (230). 



1885. Biplothmema. obtusilobum (Bronga.) Stur, Farne d. Carbon-Fl., pp. 296, 354, pi. 

 XXV, figs. 8a-c; pi. xxv/*, fig. 1. 



1888. Dqylothmema obtusilobum (Brougn.) Stur, Toula, Die Steiukolaleu, p. 187, pi. i, 



figs. 7, 8. 

 1877. Diplothmema irregulare (Sterub.) Stur, Culm-Flora, vol. ii, p. 124 (230). 

 1885.- Diplothmema irregulare (Sterub.) Stur, Farne d. Carbon-Flora, p. 296. 

 1879. Pseudopecopteris irregularis (Sterub.) Lesquereux, Coal Flora, Atlas, p. 8, pi. lii, 



figs. 1-3 (8?); text, vol. i (1880), p. 211. 

 1884. Pseudopecopteris obtusiloba (Brougn.) Lesquereux, Coal Flora, vol. iii, p. 7.53. 



1889. Pseudopecopteris obtusiloba (Brougn.) Lx., Lesley, Diet. Foss. Peuusylvauia, vol. 



ii, p. 803, text fig. 

 1893. Sphenopteris [Pseudopecopteris) obtusiloba Brongu., D. White, Bull. U. S. Geol. 

 Surv., No. 98, p. 52. 



Fronds tripinnate; or quadripinnate below ; rachis strong, flat, naked, 

 striated, slightly undulate below, becoming more flexuons toward the tip ; 

 primary pinnae broad, lanceolate, acute, pinnatifid to near the extreme apex; 

 secondary pinnse at right angles below, becoming oblique abo^^e, alternate, 

 distant, contiguous or shghtly imbricated, linear-lanceolate, acute, straight 

 or curved, those in the middle and lower portions of the primary pinnaj 

 pro^^ded with pinnte of the third order, those above bearing reduced ter- 

 tiary pinnae or pinnatifid pinnules, those still nearer the top being provided 

 with large, broad, rather triangular-ovate pinnules, divided into 3 to 5 more 

 or less deeply separated, round-obtuse lobes ; secondary and tertiary rachises 

 narrow, more or less distinctly flexuons to correspond to the insertion of the 

 pinnae or pinnules, but 'sometimes appearing nearly straight, sulcata above, 

 rounded on the lower side, finely and evenly striate, bordered by narrow 

 lamina?.; tertiary pinnae distinct, alternate, usually close, sometimes distant, 

 or even overlapping, the lower ones at a right angle to the secondary rachis, 

 the upper somewhat oblique, 12-22 mm. long, 5-12 mm. wide, more or less 

 acutely pointed, provided with 2 to 5 pairs of alternate, sessile, or broad- 

 pedicellate, half-round, ovate, or reniform and dilated, usually more or less 

 distinctly trilobate pinnules, generally close or slightly imbricated, those in 

 the lower part of the frond more distant, slightly decurrent; surface of the 

 pinnules coriaceous, curved backward somewhat near the border, and 

 marked between and parallel to the nerves with close, minute strife ; mar- 

 gins apparently thickened and traversed on the upper side by a narrow 



