KNOWLTON.] PLANTS OF THE PAYETTE FORMATION. 727 



POPULUS OCCIDENTALS n. Sp. 

 PI. XCIX, fig. 14. 



Leaves evidently of firm texture, long-ovate in outline, rounded 

 below to a truncate base and narrowed above (apex broken) ; petiole 

 not preserved; margin faintly or rather obscurely crenate-toothed, 

 with obtuse teeth; midrib slender, straight; secondaries seven or 

 eight pair, subopposite, at an angle of about 45, curving upward ; 

 finer nervation not preserved. 



This species is represented by the single example figured. The 

 part preserved is 8 cm long and was probably not far from 10 cm in length 

 when perfect. It is broadest at a point much below the middle, where 

 it is 6 cm broad. Both base and apex are wanting, but it appears that 

 it was rounded or truncate at base and acuminate at apex. The mar- 

 gin is rather obscurely crenate-toothed, the teeth obtuse. The nerva- 

 tion consists of about eight pairs of subopposite secondaries. 



This species seems to approach quite closely to Populus monilifera 

 Ait. , the cottonwood so abundant in the West. It differs slightly in 

 dentation of the margin, and in the fact that the secondaries arise at 

 a greater angle and apparently do not anastomose near the margin. 



Among fossil species it is somewhat related to P. balsamoides Gopp. , 

 from the Miocene of California. 1 But this differs in being more heart- 

 shaped at base, more obtuse at apex, and more strongly dentate at 

 margin. 



Locality: Two miles southeast of Marsh post-office, Boise County, 

 Idaho. 



SALIX ANGUSTA Al. Br. 



PL XCIX, fig. 12. 



There are a number of somewhat defective leaves that are referred 

 with little doubt to this species. 



Localities: One mile southeast of Marsh post-office, Boise County; 

 Cartwright's ranch, on Shafer Creek, Idaho. 



BETULA ANGUSTIFOLIA Newby. 

 Proc. U. S. Nat. Mus., Vol. V, p. 508, 1883; plates ined., PI. XL VI, fig. 5. 



This was described by Newberry from Bridge Creek, Oregon. The 

 specimen here referred to it is broken, but is probably correctly 

 identified. 



Locality: Idaho City, Idaho. 



BETULA, Fruit of. 

 PI. XCIX, fig. 9. 



Fruit (pistillate ament) cylindrical, 3 cm in length, 9 mm in diameter; 

 bracts rather few, acutish, about 3 mm long. 



1 Lx., Cret. and Tert. Fl., p. 348, PL LV, figs. 3, 5, 1883. 



