THE WILLOWS OF ALASKA 305 



color on both surfaces ; catkin scales usually 

 yellowish or straw-colored. 



vS. cotnmutata^ p. 317. 

 Ovary densely hairy, the capsule by expansion more spar- 

 ingly so. 

 Leaves provided beneath with a dense, white, opaque 

 covering of curled and tangled hairs. 



S. alaxefisis, p. 311. 

 Leaves not as described. 



Leaves rather narrowly elliptical-lanceolate, acute at 

 both ends, minutely and rather closely crenate-den- 

 ticulate about the whole margin, glaucous beneath, 

 the lowermost usually smooth on both surfaces, the 

 upper clothed beneath with fine appressed hairs ; 

 stalk of the ovary equalling or twice as long as the 

 nectary ; style less than i mm. long. 



S. arbusculoldes, p. 323. 

 Leaves or other parts not as described. 



Catkins appearing before the leaves, the usually 

 very short peduncle devoid of leaves, though 

 sometimes with very rudimentary leaves or 

 bracts ; leaves with permanent appressed pubes- 

 cence of short hairs beneath, dense when young, 

 sparse when old, the upper surface with some 

 similar pubescence above when young, oblong- 

 lanceolate to obovate-lanceolate, usually acute at 

 either end ; catkin scales black ; style short, 5 



mm. or less in length S. nuttallii,, p. 310. 



Catkins appearing w^ith or after the leaves, the fresh 

 growth on which the catkin is borne always 

 having either leaves or green leaf-like bracts ; 

 other organs not all as described above. 

 Leaves oblanceolate to obovate, tapering to the 

 base, usually rounded at the apex, entire or re- 

 motely glandular-denticulate, permanently sat- 

 iny beneath with a dense covering of very 

 short, straight, appressed hairs. 



S. sitc/ietisis^ p. 307. 

 Leaves not as described. 



Stalk of the ovary few to several times the 

 length of the nectary, very slender, in fruit 



