WILLOW FAMILY 193 



20. S. lasiolepis Benth. A tree 3-20 m. high, with grayish brown, smooth 

 bark; leaves oblanceolate, 10-15 cm. long, often obtuse, more or less short-villous 

 when young, in age glabrous and shining above, glaucous or ferrugineous be- 

 neath, subcoriaceous hi age; aments sessile or nearly so; bractlets rounded, dark, 

 crisp- villous; filaments slightly united at the base; capsule glabrous; stipe short; 

 style about 1 mm. long. Along streams: Calif. Utah -Ida. Wash. Son 

 Mr-Je. 



21. S. Hookeriana Barrett. A shrub or tree up to 16 m. high; twigs densely 

 velvety-canescent when young; leaf -blades broadly obovate or oval, white- 

 pubescent when young, in age dark green and more glabrate above, white-villous 

 beneath; aments subsessile, naked or nearly so; bractlets obovate, fuscous, but 

 usually hidden by the dense white-villous pubescence; capsule about 5 mm. long; 

 stipe short; style 0.5-1 mm. long. River banks: Sask. Ore. B.C. Submont. 

 Ap-My. 



22. S. balsamifera (Hook.) Barratt. Usually a shrub, about 3 m. high, 

 sometimes a small tree up to 8 m. high; leaf-blades thin, ovate, oval, or obovate, 

 acute or obtuse at the apex, rounded or subcordate at the base, dark green above, 

 glaucous beneath, 5-8 cm. long; aments 2-5 cm. long; bractlets persistent, 

 brownish or yellowish, silky- villous; capsule 6-8 mm. long; stipe about 3 mm. 

 long; style very short. S. . pyrifolia Anders. P. Columbiae Nels. & Macb. 

 BALSAM WILLOW. Swamps: Lab. N.Y. Minn. Mont. My. 



23. S. Mackenziana Barratt. A small tree or shrub, sometimes 10 m. 

 high; bark brown, glabrous; leaf-blades oblanceolate or lanceolate, 5-10 cm. 

 long, acuminate at the apex, crenate or nearly entire, dark green above, pale 

 beneath; aments 4-6 cm. long; bractlets obovate, hairy towards the base; capsule 

 glabrous, 5-7 mm. long; stipe 3-4 mm. long; style about 0.5 mm. long. DIAMOND 

 WILLOW. Along streams: Sask. Man. Ida. Calif. B.C. Mack. Sub- 

 mont. Ap-Je. 



24. S. cordata Muhl. A shrub 1.5-4 m. high; leaf -blades from oblong- 

 lanceolate and subcordate at the base to narrowly lanceolate and acute at the 

 base [var. augustata (Pursh.) Anders., the form found in the Rocky Mountains], 

 often somewhat silky-pubescent when young; staminate aments about 2 cm. 

 long, the pistillate ones 4-6 mm. long in fruit; bractlets fuscous, white-silky; 

 capsule glabrous, 6-7 mm. long; stipe 1-2 mm. long; style minute. HEART- 

 LEAVED WILLOW. Wet ground :N.B.Va Colo. Calif. B.C. Plain Mont. 

 Ap-My. 



25. S. pedicellaris Pursh. A shrub l.m. high or less; blades oblong, 

 elliptic or sometimes oblanceolate, obtuse, entire, 2-4 cm. long, 8-16 mm. wide; 

 aments about 2 cm. long; bractlets obtuse, slightly villous; capsule glabrous, 

 about 5 mm. long; stipe about 2 mm. long; style minute. S. myrtilloides Am. 

 auth., not L. BOG WILLOW. In bogs: N.B. N.J. la. Wash. B.C. Mont. 

 Ap-My. 



26. S. lutea Nutt. A shrub or small tree 5-6 m. high, with gray bark; 

 leaf -blades lanceolate, 3-7 cm. long, more or less acuminate, somewhat pubes- 

 cent when young; aments subsessile, 2-5 cm. long; bractlets brownish, white- 

 villous; capsule about 5 mm. long; stipe 1-2 mm. long; style about 0.5 mm. long. 

 YELLOW WILLOW. River banks and wet places: Man. Neb. Utah Mont. 

 Alta. Submont. -Mont. My-Je. 



27. S. Watsonii (Bebb) Rydb. A shrub or small tree 4-7 m. high; blades 

 lanceolate, short-acuminate or acute, 3-7 cm. long; aments 2-3 cm. long, almost 

 sessile; capsule ovate, about 6 mm. long; stipe hi fruit often 2 mm. long; style 

 about 0.5 mm. long. S. flava Rydb. River banks: Mont. N.M. Calif. 

 Submont. My-Je. 



28. S. Barklayi Anders. A tall shrub 1-4 m. high; leaf-blades obovate, 

 ovate or oval, 2-5 cm. long, acute or short-acuminate, more or less glaucous 

 beneath; aments on short leafy branches, 2-3 cm. long, 8-10 mm. thick; bract- 

 lets oblong, obtuse, densely white-villous; capsule about 6 mm. long, subsessile j 

 style about 1 mm. long. Mountain meadows: Alaska Wash. 'Mont.; (Gaspe 

 Peninsula) Que. Subalp. Alp. My-Au. 



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