gg TREES OF NORTH AMERICA 



Capsules glabrous. 

 Leaves acute. 



Leaves ovate or lanceolate, glaucous and conspicuously reticulate-veined below. 



11. S. balsamifera (A). 



Leaves oblanceolate to lanceolate-oblong, pale or glaucous below. 



12. S. lasiolepia (G, H). 



Leaves acuminate, lanceolate to oblanceolate. 



Leaves glabrous and glaucous below ; branchlets glabrous. 



13. S. cordata var. Mackenzieana (F, G)- 



Leaves pale, of ten silvery white below, pubescent, at least while young ; branch- 

 lete pubescent. 14- S. Missouriensis (A). 



Capsules pubescent (glabrous in 19). 



Leaves glabrous or nearly so at maturity (pubescent sometimes in 15) ; style short. 

 Leaves elliptic-oblong to lanceolate, acute, with a usually twisted apex, serrate 

 or sometimes entire. 



Leaves usually glabrous, glaucous below ; pedicel of the ovary shorter than 

 the scale ; branchlets glabrous or rarely puberulous. 



15. S. discolor (A). 



Leaves pubescent or tomentose below, often nearly glabrous at maturity ; 

 pedicel of the ovary much longer than the scale ; branchlets pubescent. 



16. S. Bebbiana (A, B, F). 



Leaves obovate to oblong, obtuse to acute, entire or nearly so ; style elongated. 

 Leaves yellow-green. 17. S. Huttallil (F, G). 



Leaves glaucous below. 18. S. amplifolia (B). 



Leaves pubescent or tomentose below. 



Leaves hoary-tomentose below, elliptic to oblong-obovate ; capsule glabrous; 

 aments thick. 19- S. Hookeriana (B, G). 



Leaves densely covered below with a shiny white tomentum ; aments slender. 

 Leaves oblong-obovate to oblanceolate ; stamens united. 



20. S. Sitchensis (B, G). 

 Leaves elliptic-lanceolate to obovate ; stamens distinct. 



21. S. Alaxensis (B). 



1. Scales of the aments of uniform color. 

 *Stamens 3 or more aments terminal. 



-t- Petioles without glands..^' ' ^ 



1. Salix nigra, Marsh. Black Willow. 



Leaves involute in the bud, lanceolate, gradually narrowed above into long taper- 

 ing usually curved tips, wedge-haped 4>r rounded below, finely serrate, thin bright 

 light green, rather lustrous,"with obscure reticulate veins, glabrous or often pubes- 

 cent on the under side of the midribs and veins and on the short slender petioles, 

 3'-6' long, ^' f' wide, sometimes conspicuously scythe-shaped (var. falcata, Torr.); 

 at the north turning light yellow before falling in the autumn; stipules semicordate, 

 acuminate, foliaceous, persistent, or ovoid, minute, and deciduous. Flowers : aments 

 terminal on leafy branches, narrowly cylindrical, l'-3' long, with short yellow scales 

 rounded at the apex and coated on the inner surface with pale hairs; stamens 3-5, 

 with filaments hairy toward the base; ovary ovate, long-stalked, glabrous, gradually 

 narrowed above the middle to the apex, with nearly sessile thick slightly divided 

 stigmatic lobes. Fruit ovate-conical, short-stalked, glabrous, about ^' long, light 

 reddish brown. 



A tree, usually 30^40 high, with usually several clustered stout stems, occa- 



