14 KEY TO THE SPECIES 



XL SALICACEiE (Willow Family) 



Dioecious trees or shrubs, with alternate undivided leaves, 

 flowers in aments and destitute of floral envelopes ; stamens 

 3-30 ; ovary 1-celled ; and fruit a pod containing numerous 

 seeds with long silky down (" cotton "). (See Plant Structures, 

 p. 255.) 



1. Salix. Bracts of the ament entire ; stamens few ; buds with a single scale. 



2. Fopulus. Bracts of the ament out-lobed at apex ; stamens numerous ; 

 buds scaly. 



1. SALIX (Willow) 



Trees or shrubs, generally growing along streams, with lithe branches and 

 mostly with long pointed leaves ; the staminate ament with 2-5 stamens to each 

 bract ; the pistillate ament with 1 slender pointed ovary to each bract, becoming 

 a 2-valved capsule. (See Plant Structures, p. 219, Fig. 196, and p. 257, Fig. 240.) 



* Stamens 2. 



-t- Leaves broadly linear ; capsule glabrous at maturity. 



1. Salix fluviatilis Nutt. (Sandbar or River-bank Willow). A shrub often 

 in dense clumps, 1-3 m. high ; the branches or young shoots very slender ; leaves 

 sparsely denticulate, pubescent only when young, 4-7 cm. long, 5-7 mm. wide ; 

 aments on short leafy branches ; capsule ovoid-conic. Common on the banks of 

 rivers' and on the borders of the smaller streams. 



-»- ■»- Leaves lanceolate or broader \ capsule silky. 



2. Salix Nuttallii Sargent (Nuttall^s Willow). A slender shrub, often 

 spreading from the root and forming dense clumps, 1-2 m. high ; bark on young 

 branchlets distinctly yellowish ; leaves oblong to obovate, from acute to broadly 

 obtuse, glabrous and dark green above, lighter and pubescent below ; aments 

 expanding in early spring before the leaves,'; capsule on a short pedicel, white- 

 tomentose, tapering to a beak. 



3. Salix Bebbiana Sargent (Bebb's Willow). A shrub or small bushy tree, 

 2-5 m. high, not spreading from the root, though often branched from the base ; 

 leaves elliptic to lanceolate, acute, entire or nearly so, puberulent above, pale and 

 tomentose beneath ; aments expanding with the leaves ; capsule long, taper- 

 pointed, on a slender pedicel half as long as the capsule. 



* » Stamens 3-5. 



4. Salix amygdaloldes Anders. (Peach-leaf Willow). Becoming a small 

 tree ; leaves lanceolate or broader, 5-9 cm. long, serrate, taper-pointed, pubescent 

 when young only; aments appearing with the leaves ; capsule ovoid, glabrous, 

 becoming as long as the fllitorm pedicel. 



3. POPULUS (Cottonwood. Aspen) 



Trees with leaves from lanceolate to broadly deltoid, the buds with resinous- 

 aromatic scales ; staminate flowers 1 to each bract, with 8-30 or more stamens ; 

 pistillate flowers also single in the axils of the bracts of the ament, with 2-4 elon- 

 gated styles. 



