THE WILLOWS OF ALASKA 303 



Leaves broadly obovate or orbicular, rounded or retuse at the apex, 

 commonly 4 to 6 mm., and rarely exceeding 10 mm., in length ; 

 pistillate catkins globose to oblong, few- (usually 2- to 8-) 



flowered; ovary smooth S. leiocarpa, p. 338. 



Leaves oblanceolate to obovate, acute to obtuse at the apex, taper- 

 ing to the base, commonly 10 to 15 mm. long; pistillate cat- 

 kins cylindrical, many-flowered ; ovary usually hairy. 



S. phlebophylla^ p. 336. 

 Leaves not with all the characters given above. 



Leaves orbicular to oval, glaucous and very prominently reticu- 

 lated beneath, rugose above ; catkins equaled or nearly equaled 

 by their peduncles ; scales of the catkins reddish purple, usually 

 smooth on the outside, several times longer than the hairs of the 

 margin and inner surface; capsules hairy; stigma sessile or 



nearly so S. reticulata^ p. 340. 



Leaves or other parts not as described above. 



Plant prostrate, cespitose ; branches very slender, a millimeter 

 or less in diameter, becoming firmly rooted ; leaves oval to 

 orbicular or nearly so ; catkins oblong to globose ; ovaries 

 hairy or sometimes nearly smooth, but not glaucous ; style 

 plainly developed but less than a millimeter in length. 



S. Polaris, p. 335. 

 Plant not with all the characters given above. 



Leaves very smooth on both surfaces, except for a few long 

 hairs (early deciduous) on the margins and midrib when 

 young, bright green and shining above, glaucous beneath, 

 rhombic-oblanceolate or sometimes rhombic-obovate, nar- 

 rowly wedge-shaped at base and usually at the apex also ; 

 stipules narrowly linear-lanceolate, persistent, serrate ; cat- 

 kins sessile or nearly so on old wood, the scales black, ob- 

 lanceolate ; stalk of the hairy capsule about as long as the 

 nectary; style about i to 1.5 mm. long. S.fulchra, p. 319. 

 Leaves or other parts not as described above. 



Ovary and capsule smooth, at least over most of its surface. 



Plant prostrate or nearly so, less than a foot in height. 



Leaves finely and evenly crenate about the whole 



margin ; catkins almost sessile, but the very short 



peduncle bearing a few small leaves. 



S. myrtillifolia, p. 325. 



Leaves entire, or sometimes with a few scattered teeth 



below, catkins borne on a well-defined leafy peduncle 



