SALICACEiE 



27 



4. S. cordata, Muhl. 



Leaves pubescent when young, oblong-lanceolate, serrate, green on both 

 sides or paler beiieath, acute at the apex and subcordate at the base; stipules 

 large, oblique, serrulate, usually persistent; catkins appearing before the 

 leaves, with two bracts at the base, the sterile 

 about 1 in. long, the fertile becoming much 

 longer in fruit; stamens 2; style short. A 

 large shrub 6-12 ft. high, usually growing in 

 clumps. Moist places, Man.-Alta. 



Fig. 18. — Salix 

 Candida. 



Fig. 19. — Salix 

 desertorum. 



Fig. 20 . — Salix 

 cordata. 



5. S. desert6rum, Richards. Desert Willow. 



Leaves oblong to lanceolate, tapering to both ends, pubescent at least while 

 young, entire or nearly so ; stipules early deciduous ; catkins appearing with 

 the leaves, with leafy bracts at the base about J in. long ; stamens 2 ; stigma 

 2-clef t ; capsule densely tomentose. A tall shrub with purplish green twigs. 

 Dry slopes, Cypress Hills to Rocky Mts., and northward. 



2..POPULUS. Poplar. 



Flowers from an irregular eup-shaped disk; 

 bracts irregularly out at the apex; stamens 

 8-60, distinct; stigmas 2 or 4, long; seed pods 

 2-4-valved; catkins appearing before the 

 leaves. Trees with broad, often heart-shaped 

 leaves on flattened petioles. 



1. P. tremuloides, Michx. American Aspen. 



A slender tree with smooth greenish white bark ; 

 leaves heart-shaped, sharp-pointed; petioles long, 

 slender, and flat. The common ' white poplar ' of 

 the prairie region. Man.-Alta. 



Fig. 21. — Populus 

 tremuloides, 



