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slightly silkly beneath when young. If it were not for the 
sessile stigmas, it would be grouped among the Arcticae, 
next to S. Grocnlandica, which it most resembles. The cat- 
kin is about 1 cm. long, many-flowered; the bracts fuscous, 
broadly obovate, somewhat villous, the capsule rather densely 
white-villous. 
ARCTICAE, 
Cespitose willows, generally only a few decimeters high, 
with entire-margined leaves, catkins at the ends of short leafy 
branches, appearing with the leaves, more or less densely 
white-tomentose or villous capsules and an evident style. 
Leaves pander or when young covered with long white hairs parallel to 
e midrib, in age generally glabrate. 
Pare fuscous, obovate, truncate or obtuse. 
Leaves very thin, nearly orbicular; catkins few-flowered. 
S. 
Leaves not very ee obovate to oblanceolate ; eee many-flow- 
e in enera. 
oO 
oO 
wv 
a 
oO 
Leaves and young twigs generally darkening in drying. 
eaf-blade rounded obovate, 10-30 mm. long; catkins 15-30 
mm. long. 8. S. diplodictya. 
Leaf-blade obovate (seldom obcordate), 25-50 mm. long; 
catkins 25~80 mm. long. 
Leaf-blade broad, obovate or obcordate, strongly reticu- 
ate, obtuse. 9. S. arctica. 
Leaf- one narrower, obovate or rarely obovate-lanceo- 
late, not strongly reticulate, often acutis 
10. S, aastieaie 
Leaf-blade obovate, 10-20 mm. long; catkins 10-20 mm 
long. 11. S. Groenlandica. 
Leaves and yellow or light brown young twigs not darkening in 
drying. 
Leaves strongly reticulate, subcoriaceous, their remnants 
more or less persisten alaeoneura. 
cake not persistent, not s | Dies (moderately 
ongly veined only in S. callicarpaea). 
pie creeping Rocky Mountain species. 
eaves obovate; catkins ake 
3. S. petrophila. 
Leaves narrowly oblanceolate; catkine few-flow- 
ere Iq. S. fenera. 
Eastern species with erect or spreading branches. 
Leaves obovate or oblanceolate, acute. 
15. S. Macounizt. 
Leaves broadly obovate, obtuse. 
16. S. callicarpaea. 
