74 MESOZOIC FLORAS OF UNI TED STATES. 



crenate margins. In each lol)e there is a parent nerve that splits up into 

 liranches. It may give off one or more pairs of lateral nerves that go off 

 ver>- obliquely. The nerve gi'oup has a flabellate character. No fruc- 

 tification was found. The plant is prohal)l>' a new species. It reseml)les 

 veiy much the Pecoptens ohtuHifolin (Murray) Lindley & Hutton" and 

 may be the Oregon representative of it. In the English fossil, however, 

 the ultimate pinnae, corresponding to the pinnules of this plant, are much 

 longer, and fructification was found. Phillips identifies the species of 

 Lindley & Hutton with his Pecoptens c.rilis." Seward regards Pecopteris 

 cxilis as a Klukia.'' 



PI. XI, Fig. 13. shows the specimen natural size, and Figs. 14 and 

 15 give enlargements to show details of nerves. 



Genus SCLEROPTERIS Saporta. 



SCLEROPTERIS OREGONENSIS Folltaiue 11. sp. 



PI. XII, Figs. 1-3. 



A single specimen of a fern was found of pretty good size and fairly 

 we 1 preserved at locality No. 19. According to Saporta's diagnosis 

 of the genus Scleropteris,'' this genus clearly includes the plant in cjues- 

 tion. The specimen shows a considerable portion of a penultimate 

 pinna, which bears fragments of a number of ultimate pinna', with pin- 

 nules. The ultimate pinnse are very short, the longest of them not 

 surpassing about 3 cm. The rachis is narrowly winged. The pinnules 

 are rigid and have a very thick leaf substance that conceals the nerves, 

 so that they generally are diflftcult to make out. The lowest pinnule 

 on the upper side of the rachis is oblong, obtuse, and larger than the 

 rest. It is crenate on the margins or has shallow obtuse teeth. The 

 other, and normal pinnules, are not more than 5 mm. long and about 

 3 mm. wide. They are entire, oblong-elliptic in form, with very obtuse 

 tips, and go off obliquely from the rachis, with a slight inclination toward 

 the ends of the pinna^. They are decurrent, forming the wing. All 

 the pinnules are constricted at base. The nerves are immersed appa- 

 rent y in the leaf substance. They are composed of a parent nerve 



"Foss. Fl. Gt. Biit., Vol. Ill, pp. 15-16. pi. fhiii, fifr. 1. 



''Geology of Yorkshire, 3d. od., p. 210, pi. viii, fig. l(i. 



'Jura-ssie Plants in the Manchester Museum, p. 4; Jur. Fl. Yorkshire Con.st. p. 1,30. 



''Pal. Franraise, Plantes Jurassiques, Vol. 1, pp. 364-36.5. 



