192 SALICACEAE 



aTients obovate, those of the pistillate ones lance-oblong; capsule almost sessile, 

 4-5 mm. long. WHITE WILLOW. Moist ground, along streams: N.B. Pa. 

 Colo.; escaped from cultivation, native of Eu. Plain. Ap-My. 



11. S. melanopsis Nutt. A shrub or small tree; bark chestnut-brown; 

 young branches puberulent; leaf -blades oblanceolate or elliptic, subsessile, about 

 5 cm. long, 1 cm. wide, silky-hairy when young, blackening in drying, somewhat 

 glaucous, finely serrate; aments at the end of leafy branches, 5-7 cm. long, cylin- 

 dric; bractlets linear-oblong, more or less erose; capsule lanceolate, glabrous. 

 DUSKY WILLOW. River banks: B.C. Mont. Ore. Submont. My-Jl. 



12. S. exigua Nutt. A shrub or small tree sometimes 6-7 m. high; twigs 

 yellowish or light brown, silky-pubescent when young; leaf -blades linear to 

 narrowly linear-lanceolate, 2-8 cm. long, yellowish, silky; staminate aments 

 2-6 cm., the pistillate ones 3-5 cm. long; bractlets of the former obovate, of the 

 latter broadly lanceolate; capsule elongate-ovoid, slightly silky when young, 

 soon glabrate, 4^-5 mm. long. S. luteosericea Rydb. SANDBAR WILLOW. Sand- 

 bars: Sask. Okla. Ariz. B.C. Ore. PlainMont. My-Jl. 



13. S. stenophylla Rydb. A shrub 2-5 m. high; young shoots silvery- 

 pubescent; leaves narrowly linear, 3-7 cm. long, acute, entire or minutely and 

 distantly denticulate, silky-strigose; pistillate aments 3-4 cm. long; bractlets 

 oblanceolate; capsule glabrous, about 6 mm. long; staminate aments 2-3 cm. 

 long; bractlets more obtuse and more villous. River banks: Colo. N.M. 

 Ariz. Plain Submont. My-Jl. 



14. S. interior Rowley. A shrub 1-4 m. high, occasionally a tree 6-9 m. 

 high; twigs pubescent when young; leaf -blades 6-10 cm. long, less than 1 cm. 

 wide, lance-linear, remotely dentate; aments 2-5 cm. long; bractlets glabrous or 

 hairy toward the base, ovate or obovate, rarely oblong; capsule appressed- 

 silky when young, soon glabrate. S. longifolia Muhl. SANDBAR WILLOW. 

 River banks and snores: Que. Va. La. Tex. Sask. Plain. Je-Jl. 



15. S. linearifolia Rydb. A low shrub, with reddish bark; leaf -blades 

 narrowly linear, 4-10 cm. long, remotely dentate; aments loosely flowered, 3-4 

 cm. long; bractlets linear-lanceolate, acute, almost glabrous; capsule almost 

 glabrous, 3-4 mm. long. S. rubra Richards. S. tenerrima (Howell) Heller. 

 Sand-bars: Sask. Okla. Colo. Wash. Plain. My-Je. 



16. S. sessilifolia Nutt. A shrub or small tree sometimes 10 m. high; 

 young branches canescent; leaf-blades linear-lanceolate to linear or oblong, 5-10 

 cm. long, sessile, obscurely and remotely denticulate or entire, silvery-canescent 

 when young, in age more glabrate; aments 6-8 cm. long, nearly 1 cm. thick, 

 often several together; capsule silky when young, glabrate in age. Sand-bars: 

 (? Mont.) Colo. Calif. Wash. Submont. Je-Jl. 



17. S. argophylla Nutt. A tree or large shrub, usually about 5 m. high; 

 young twigs yellow and puberulent, soon glabrate; leaf -blades narrowly linear- 

 lanceolate, about 5 cm. long, sessile, densely white-silky on both sides; aments 

 3-5 cm. long, 1-2 cm. thick, often in pairs or threes; bractlets of the staminate 

 aments oblong and obtuse, those of the pistillate aments lanceolate and acute; 

 capsule densely silky, sessile. River banks: Mont. Tex. Calif. Wash. 

 Plain Submont. My-Jl. 



18. S. macrostachya Nutt. A shrub or small tree 1-6 m. high; twigs 

 densely villous; leaf -blades linear-oblanceolate, about 5 cm. long, sessile, densely 

 white- villous; aments often several together, 2-3 cm. long, densely flowered; 

 bractlets densely villous all over, oblong; capsule densely villous, sessile. River 

 banks: Calif. Ida. B.C. Submont. My-Jl. 



19. S. Sandbergii Rydb. A shrub or small tree; branches chestnut-brown; 

 leaves oval or elliptic, 2-4 cm. long, silky on both sides, grayish above, silvery 

 beneath; pistillate aments sessile, naked, 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. S. boiseana A. Nels. Valleys: Ida. 

 Submont. Ap-Je. 



