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13. 
THE WILLOWS OF OHIO. 269 
Leaves oblong, hair long and straight. S. interior. 
Leaves ovate, hair shorter, matted. S. adenophylla. 
6. Pubescence not lustrous. 7. 
6. Leaves clothed below, sometimes only thinly, with sil- 
very short hair having a lustrous appearance al- 
most like changeable silk, glabrous above, narrow, 
narrowed to both ends, sharply serrate, generally 
blackening in drving, venation irregular; spraw- 
ling shrub. S. sericea. 
Leaves narrow, oblong or spatulate, broadest above the 
middle, margins mostly revolute, venation very prom- 
inent below. 8. 
Not as above, margins serrate (or rarely entire but not 
revolute.) 10. 
8. Hair dull red brown, leaves dull above, not revolute. 
S. discolor. 
8. Pubescence not ferruginous, leaves revolute. 9. 
Secondaries depressed above, leaves very thickly snowy to- 
mentose, especially on the veins, margins mostly entire; 
dwarf prairie shrub, northern. S. candida. 
Secondaries not depressed above, leaves gray tomentose, 
margins mostly undulate; growing larger, in hillside 
swamps and uplands. S. humilis. 
10. Leaves coarsely serrate with relatively distant, blunt 
teeth incurved except when young, or entire; 
swamp shrubs with ascending stems. 11. 
10. Leaves closely and sharply serrate, rarely entire, teeth 
not incurved. 12. 
Veins often depressed above, dirty white tomentose and 
very prominent on the under surface; northern only. 
S. bebbiana. 
Veins not depressed above, not very prominent beneath 
nor especially hairy, frequently ferruginous. 
S. discolor. 
12. Pubescent on both surfaces. 13. 
12. Pubescent only below. 14. 
Leaves ovate, subcoriaceous, very glandular, rarely entire. 
tomentose with matted wool, green on both sides; shrub, 
northern. S. adenophylla 
Leaves lanceolate, thin, not especially glandular, pubescent 
with parallel hairs, glaucous beneath; tree. S. alba. 
14. Pubescence evenly distributed. 15. 
14. Pubescense mostly on the veins, wooly. 16. 
Venation regular, neither arching nor looping; arborescent. 
S. alba. 
Venation irregular, arching or looping; sprawling shrub. 
S. sericea. 
