FERNS— SPHENOPTERIDE.E—ALOIOPTERIS. 73 



species as those from Missouri. But Andra's original figures/ as well as 

 those given later by Weiss^ and Zeiller,^ seem to represent a plant with 

 more oblique pinnules, comparable to those of Spheno'pteris incequilateralis Lx., 

 which are much more dissected. In the comparatively very few specimens 

 from Missouri in which the pinnules have eloug-ated to a length of 1 cm. or 

 more the lamina is still but little dissected, and the pinnules, which may be 

 considered as pinnatifid, are constricted but slightly at the base. Imperfect 

 fragments of such pinnse are illustrated in PL XXII, Fig. 3, and PI. XXIII, 

 Fig. 4. Were this pinnatifid stage common in the development of the 

 species, we should see many such fragments in the collections mingled with 

 the attending segments of various degrees of maturity, including portions of 

 rachises, 1 cm. or more in width, provided on both sides with alternating 

 jDinnfe of the usual form. The relation of the small fragments of a young 

 compound pinna (PL XXIII, Fig. 1) to this species is shown by both the 

 nervation and the peculiar angular dentition. 



The fertile pinnae, which seem to have been borne directly on the pri- 

 mary pinnae, do not, as shown in PL XXIII, Figs. 4 and 5, diff'er in general 

 form and arrangement from the sterile pinnge. The sporangia, which are 

 oblong or oval, .75 to 1.25 mm. long, .4 to .6 mm. wide, rounded at one end 

 and rather obtuse at the other, are borne, in groups apparently, on the 

 lower surface of the slightly reduced pinnules, which are so crushed in 

 the shale as to make them seem entirely covered by the flattened sporangia. 

 In a few cases it may be seen that the sporangia are attached by the ends 

 in round groups, perhaps of 5 to 7 sporangia each, the members of which 

 are sometimes spread apart at the top. 



The question of the systematic position of the groujD, including Pecop- 

 teris cristata Gein., Asplenites Sternhergii Ett., Pecopteris erosa Lx., P. georgi- 

 ana Lx., and P. serrula Lx., is one that has perhaps not yet reached its 

 final settlement. Ettingshausen's Asplenites Sternhergii, to choose a typical 

 example, has been referred by various authors to Pecopteris,^ Oligocarpia,^ 

 Sphenopteris,^ and Saccopterls,'' while other species, no doubt congeneric^ 



' Sphenopteris Essmyhii Andrii, Vorweltl. Pfl. Steink., 1866, pi. vii, figs. 2, 3, p. 20. 



2 Aus d. Fl. d. Steink., 1881, pi. xii, tig. 76. 



3 Fl. foss. houill. Valenciennes, Atlas, 1886, pi. ix, figs. 1, 2 ; text, 1888, pp. 122, 125, tig. 41. 

 ■•Sohimper, Traite, vol. i, 1869, p. 526. 



"Stur, Culm- Flora, vol. ii, 1877, p. 294. 

 "Weiss, Aus d. Fl. d. Steink., 1881, p. 12. 

 ' Stur, Fame d. Carbon-Fl., 1883, p. 165. 



