WILLOW FAMILY 193 



20. S. lasiolepis Benth. A tree 3-20 m. high, with grayish bro\\-n, 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 in 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^lda. — Wash. Son, 

 Mr-Je. 



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

 velvety-canoscent 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. SubmonL 

 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. Colamhiae 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, hair}- 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. Suh- 

 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. augustala (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-siUcy; 

 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, 

 Ai>-My. 



25. S. pedicellaris Pursh. A shrub 1 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 in fruit often 2 mm. long; st^'le 

 about 0.5 mm. long. S, flava Rydb. River banks: Mont. — X.M. — CaUf. 

 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; 

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

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



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