THE WILLOWS OF OHIO. 269 



5. Leaves oblong, hair long and straight. S. interior. 



5. Leaves ovate, hair shorter, matted. 5. 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 drying, venation irregular; spraw- 

 ling shrub. 5. sericea. 

 7. Leaves narrow, oblong or spatulate, broadest above the 

 middle, margins mostly re volute, venation very prom- 

 inent below. 8. 

 7. Not as above, margins serrate (or rarely entire but not 

 re volute.) 10. 

 8. Hair dull red brown, leaves dull above, not revolute. 



5. discolor. 

 8. Pubescence not ferruginous, leaves revolute. 9. 

 9. Secondaries depressed above, leaves very thickly snowy to- 

 mentose, especially on the veins, margins mostly entire; 

 dwarf prairie shrub, northern. 5. Candida. 



9. Secondaries not depressed above, leaves gray tomentose, 

 margins mostly undulate; growing larger, in hillside 

 swamps and uplands. 5. 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. 

 11. Veins often depressed above, dirtv white tomentose and 

 very prominent on the under surface; northern only. 



5. bebbiana. 

 11. 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. 

 13. Leaves ovate, subcoriaceous, very glandular, rarely entire, 

 tomentose with matted wool, green on both sides ; shrub, 

 northern. 5. adenophylla 



13. Leaves lanceolate, thin, not especially glandular, pubescent 

 with parallel hairs, glaucous beneath ; tree. 5. alba. 



14. Pubescence evenly distributed. 15. 

 14. Pubescense mostly on the veins, wooly. 16. 

 15. Venation regular, neither arching nor looping; arborescent. 



5. alba. 

 15. Venation irregular, arching or looping; sprawling shrub. 



S. sericea. 



