WILLOW FAMILY 189 



Mature leaves rather thin, dull; length of the blade less than three times 



its width. 22. S. balsamifera. 



Mature leaves firm, dark green, shining above, pale beneath; length of 

 the blade three times the width or more. 

 Stipe in fruit 2-4 times as long as the bractlets; mature leaves slightly 



serrate. 23. S. Mackenziana. 



Stipe slightly if at all exceeding the bractlets. 

 Mature leaves lanceolate, strongly serrate. 



24. S. cordata. 

 Mature leaves oblong or oblanceolate, entire. 



25. S. pedicillaris. 

 Leaves yellowish green; young branches light yellow; aments naked or sub- 

 tended by a few small leaves. 



Leaves usually long-acuminate, serrate. 26. S. lutea. 



Leaves acute or rarely short-acuminate, entire or indistinctly crenulate. 



27. S. Watsonii. 

 Capsule short-stipitate or subsessile; stipe in fruit less than 1.5 mm. long and much 

 shorter than the bractlets; style 0.5-1 mm. long. 

 Leaves more or less dentate, rarely subentire. 



Young leaves and twigs rather densely pubescent with long wliite hairs; 

 the former glandular-denticulate or dentate. 

 Bractlets fuscous. 2<S. S. Barklayi. 



Bractlets yellowish or light brown. 29. S. commutata. 



Young leaves glabrous or slightly pubescent. 



Capsules 7-8 mm. long; leaf-blades broadly ovate or obovate, glandular- 

 dentate. 30. S. Tweedyi. 

 Capsule 4-6 mm. long; leaf-blades narrowly obovate to lanceolate. 

 Leaves dark green above, not reticulate. 



Leaves blackening in drying, finely glandular-dentate. 



31. S. conjuncla. 

 Leaves not blackening in drying. 



Leaves thin, ovate, elliptic, or obovate, Ught green and dull 



above; capsule ovoid. 32. S. padophylla. 



Leaves thick, firm, slilning above; capsule lance-ovoid. 

 Style 0.5-1 mm. long; aments on short leafy branches, 



2-3 cm. long. 33. S. monlicola. 



Style 1-1.5 mm. long; aments subsessile, 3-4 cm long. 



34. S. curtiflora. 

 Leaves yellowish green, conspicuously reticulate, thin. 



Leaves acute or acuminate, serrate. 35. S. pseudomyrsinites. 



Leaves obtuse or rounded at the ape.x, crenate. 



36. S. myrtillifolia. 

 Leaves entire, linear, lanceolate, oblanceolate, or oblong; aments subsessile, 

 naked. 

 Leaves permanently silky; a low shrub. 37. S. Wolfii. 



Leaves glabrous in age; tree or tall shrub. 20. S. lasiolepis. 



Branches with a bloom, purple. 38. S. irrorata. 



VI. Retusae. 

 One species. 39. S. Dodgeana. 



VII. ROSTR.\T.\E. 



Leaves linear to lanceolate or oblanceolate. 



Leaves sharply serrate, narrowly lanceolate, 5-10 cm. long. 40. S. petiolaris. 

 Leaves entire or nearly so, linear, less than 5 cm. long. 



Leaves more or less silky, oblanceolate; branches purplish, usually with a bloom. 



41. S. Geyeriana. 

 Leaves not silky, linear; branches without a bloom. 42. S. gracilis. 



Leaves ovate to obovate or broadly oblanceolate. 



Bracts fuscous, obovate or cuneate. 43. 5. discolor. 



Bracts yellow, linear-oblong or lanceolate. 



Mature leaves thin, glabrous. 44. S. perrostrata. 



Mature leaves firm, pubescent or tomentose beneath. 45. S. Bebbiana. 



VIII. C.\PREAE. 



Capsule 8-10 mm. long; at least the staminate aments not leafy-bracted. 



Leaves obovate, entire or nearly so, densely silky and fulvous, almost velutinous when 

 young, in age glabrate above; bractlets fuscous, obovate. 



46. S. Scouleriana. 

 Leaves oblanceolate, closely and finely serrulate, puberulent when young; bractlets 



yellow, oblong. 67. S. MacCalliana. 



Capsule 6 mm. long or less; aments leafy-bracted. 



Bractlets black, thinly pilose; style about 1 mm. long; leaves glabrate in age. 



47. S. Lemmoni. 

 Bractlets brownish, villous; style about 0.5 mm. long; leaves silvery-silky beneath. 



54. S. argyrocarpa. 

 IX. Argentea. 

 Aments more than 1 cm. broad; ovary over 5 mm. long. 

 Leaves obovate, ovate, or broadly oblanceolate. 



Bractlets obovate, fuscous; leaves usually obovate. 



Twigs white-villous; leaf-blades entire. 48. S. alazensis. 



