l82 



The Willows 



The name is the ancient name of the willow, the type species being the White 

 willow of Europe, Salix alba Linnaeus. 



In addition to the arborescent species there are about loo kinds of shrubs 

 known from our area. Willows hybridize very freely, and many natural crosses 

 between species have been noted. 



A. Capsule glabrous, at least when mature (except in 5. sessilifolia). 



a. Stamens 3 to ii (sometimes only 2 in S. jragilis). 



Pedicels of capsules slender, three to five times as long as the gland 

 (short in S. Toiimeyi); native trees. 

 Stipules and petioles without glands. 

 Leaves green beneath. 



Bark of the twigs green to brown. 



Ovary glabrous; stamens 3 to 7; bracts of catkins ovate 



to oblong; eastern tree. i. 5. nigra. 



Ovary and young capsule more or less pubescent; 

 stamens 5 to 11; bracts of catkins mostly obovate; 

 California tree. 2. 5. 



Bark of the twigs yellow to yellow-green; southwestern 



tree. 3. 5. 



Leaves glaucous or pale beneath. 



Pedicels filiform, often nearly as long as the capsules or 

 longer. 

 Bracts of catkins entire-margined; eastern tree. 4. 5. 



Bracts of catkins dentate; California tree. ' 5. S. 



Pedicels distinctly shorter than the capsule, often very short. 

 Leaves narrowly lanceolate; capsules almost sessile. 6. 6'. 



Leaves broadly lanceolate; capsules distinctly stalked. 7. 5. 



Stipules and usually also the petioles with glands. 

 Leaves ovate-lanceolate; glands of stipules and petioles usually 



stalked; eastern tree or shrub. 8. S. lucida. 



Leaves lanceolate; glands sessile; western trees or shrubs. 



Leaves green on both sides. 9. 5. 



Leaves white-glaucous beneath. 10. 5. 



Pedicels of capsules short, only about twice as long as the gland; 

 introduced European tree. 



b. Stamens 2 only. 



Filaments hairy toward the base; bracts of the catkins deciduous. 

 Pedicels of the capsules less than i mm. long; large trees intro- 

 duced from Europe. 

 Branches not drooping; leaves lanceolate. 12. S. 



Branches drooping; leaves linear-lanceolate. 13. S. 



Pedicels of the capsules i to 3 mm. long; native trees or shrubs. 

 Capsule glabrous when mature. 



Leaves sharply serrulate, glabrous or slightly hair}' when 



mature; eastern tree or shrub. 

 Leaves entire, or minutely and distantly serrulate, silky- 



canescent; western tree or shrub. 15. S. 



Capsule densely white-silky, even when mature. 16. 5. 



Filaments glabrous; bracts of pistillate catkins persistent. 



vail j cola. 

 Wrightii. 



longipcs. 

 lavigata. 



Toiimeyi. 

 amygdaloides. 



lasiandra. 

 Lyallii. 



II. 5. jragilis. 



alba, 

 babylonica. 



14. 5. interior. 



exigna. 

 sessilifolia. 



