passing body of scale; stamens 2, the glabrous filaments often connate toward 

 base; capsules 4-8 mm. long, villous-tomentose; style and stigma combined 1.5-2.5 

 mm. long. S. petrophila Rydb. 



Wet meadows, seepage grassy slopes among rocks, in N. M. (Rio Arriba and 

 Taos COS.) ; circumboreal, s. in Am. to Que., N.M. and Calif. 



15. Salix glauca L. 



Erect branching shrubs to about 15 dm. tall; twigs reddish and villous-tomentu- 

 lose; stipules often less than 1 mm. long, deciduous; petioles yellowish, 4-10 mm. 

 long; blades elliptic to obovate or oblanceolate, obtuse to acute at apex, 2.5-4.5 

 (-6) cm. long, 1-2 (-3) cm. wide, loosely villous-tomentulose when young, often 

 becoming glabrate with age, essentially entire, conspicuously glaucous beneath; 

 aments coetaneous, on short leafy-bracted peduncles to 2 cm. long; scales light- 

 to dark-brown or occasionally blackish; staminate aments cylindric, 1-3 cm. long; 

 stamens 2, the free or basally united filaments glabrous or hairy at the base; 

 pistillate aments 2-5 cm. long at maturity; capsules 4-8 mm. long, hairy, on pedi- 

 cels 1-2 mm. long; styles 0.5-0.8 mm. long, longer than the bilobed stigmas. 



Boggy or wet places in high mts., in N. M. (San Miguel and Taos cos.); cir- 

 cumboreal, s. in Am. to Que., Man., Alta., and B.C., and in Rocky Mts. to N. M. 



16. Salix irrorata Anderss. 



Shrubs to 3 m. tall; twigs usually dark reddish-brown, usually pruinose, puberu- 

 lent or glabrous; buds stout, broadly ovoid, brownish; leaf blades narrowly oblong- 

 elliptic to oblanceolate, acute to short-acuminate at apex, cuneate at base, 5-6 

 (-7) cm. long, 1-1.2 cm. wide, entire or those of shoots undulate-serrate, when 

 mature dark green and glabrous above and green or somewhat glaucous beneath; 

 staminate aments sessile, 1.5-2 cm. long; stamens 2, the glabrous filaments united 

 at base; pistillate aments subsessile, 2.5-4 cm. long; scales ovate to obovate, 

 blackish, with long white hairs; capsules ovoid-conic, glabrous, 3-4 mm. long; 

 styles 0.5-0.7 mm. long, the short stigmas entire or emarginate. 



Along streams and edge of wet meadows in canyons, in N. M. (widespread 

 in mts.) and Ariz. (Apache, Cochise and Pima cos.); also Colo. 



17. Salix lasiolepis Benth. Arroyo willow. 



Shrub or small tree usually to 6 or rarely to 12 m. tall; twigs yellowish-olive 

 to reddish, downy-puberulent to glabrous; stipules essentially wanting; petioles 

 mostly 5-15 mm. long; blades thickish, revolute-margined, entire or sometimes 

 shallowly toothed or sinuate, dark-green above, conspicuously paler and glaucous 

 beneath, oblanceolate to oblong-elliptic, 3-1 1 cm. long, 5-30 mm. wide, short- 

 hairy when young, with age glabrous above and strigose-puberulent beneath; 

 aments precocious, sessile or with peduncle to 1 cm. long; scales blackish, per- 

 sistent, densely long-wooly-villous; staminate aments 2.5-4.5 cm. long; filaments 

 2, glabrous; pistillate aments 2.5-6 cm. long; capsules 3-5 mm. long. 



Along streams, in swamps and about springs, in w. Tex. to Ariz. (Apache, 

 Navajo, Coconino, s. to Cochise and Pima cos.); Ida. and Wash., s. to w. Tex,, 

 Ariz., Calif, and n. Mex. 



Our material is usually referred to the narrow-leaved var. Bracelinae Ball. 



18. Salix rigida Muhl. Yellow willow. 



Coarse shrub usually 2-4 or rarely to 9 m. tall, occasionally somewhat arbores- 

 cent; twigs elongate and slender, yellow to reddish-brown, puberulent but be- 

 coming glabrous; stipules foliaceous, to about 1 cm. long, ovate to lunate, serru- 

 late to entire; petioles to about 2 cm. long; blades typically lanceolate and broadly 

 rounded to somewhat cordate at base, varying to elliptic or oblanceolate-obovate, 



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