304 Rydberg: Studies ox the Rocky Mountain flora 



Salix Sandbergii sp. nov. 



Bark of the branches reddish chestnut brown, finely puberulent 

 when young; leaves oval or elliptic, 2-4 cm. long, densely white- 

 silky on both sides, grayish above, silvery beneath, entire or 

 nearly so; pistillate aments sessile, naked, about 4 cm. long; 

 bractlets purple, obovate-spatulate, 3 mm. long, white-pilose; 

 capsule glabrous, 4-5 mm. long; stipe about 1.5 mm. long; style 

 about 0.5 mm. long; lobes of stigma short. 



The type was distributed as Salix lasiolepis Benth., to which it is 

 not at all closely related. The leaves resemble somewhat those 

 of S. sitchensis Sanson and S. hella Piper, but the capsule is glabrous 

 and the plant belongs to the S. cordata group. On account of the 

 white leaves it would be placed next to S. Hookeriana Barrett, 

 but the leaves are silky, not villous, and entire, and the aments 

 and capsules are much smaller. It grows on banks of streams. 



Idaho: Valley of Hatwai Creek, April 28, 1892, Sandherg, 

 MacDougal & Heller 7/ (type, in herb. N. Y. Bot. Garden). 



The following species of willows are here recorded for the 

 Rocky Mountain region: Salix erythrocoma Barrett (5. argnta 

 erythrocoma Anderson), S. Incida Muhl., S. Hookeriana Barrett, 

 5. conjuncta Bebb, 5. MacCalliana Rowley, 6". alexensis (An- 

 ders.) Coville, S. Barrettiana Hook., S. Seemanii Rydb., 5'. 

 Drtimmondiana Barrett, S. arhiiscidoides Anders., S. desertoriim 

 Richards., S. saskatchewana Seem., and S. Fernaldii Blankinship, 

 from the Canadian Rockies south of the 55° parallel; and 5. con- 

 juncta Bebb and S. Fernaldii Blankinship also from Montana. 



ULMACEAE 



Celtis rugosa sp. nov. 



A tree, 5-10 m. high, with rounded crown; bark gray, corky; 

 twigs brownish, pubescent when young; petioles 6-10 mm. long; 

 leaf blades broadly ovate, oblique, 4-7 cm. long, somewhat cordate 

 at the base, short-acuminate, sharply serrate except at the base 

 and at the apex, coriaceous, dark green, very shiny and slightly 

 scabrous above, brownish or yellowish green, dull, puberulent 

 beneath, strongly reticulate and rugose; pedicels 15-25 mm. long; 

 fruit globose, about 8 mm. in diameter, brownish; style short but 

 evident. 



This species is related to C. reticulata Torr. but differs in its 



