SALICACEAE 99 



—Pennsylvania: Monroe ; Allegheny ; Northampton ; Delaware; 

 I/EHiGH ; Sullivan. 



3. Populua heterophylla L. Swamp or Downy Poplar. (Man. p. 

 308 ; I. F./. Ii6t.) In swamps, Conn, and N. Y. to Ga. and La., north in 

 the Miss, valley to Ind. and Ark. — Pennsylvania : CHESTER ; Delaware. 



4. Populu3 tremuloides Michx. American Aspen. (Man. p. 310 ; 

 I. F. /. i/^o.) In dry or moist soil, Newf. to Alaska, south to N. J. 

 Pa., Ky., in the Rocky Mts. to Mex. and to Lower Ca] .—Pennsyl- 

 vania : Northampton ; Monroe ; Chester ; Schuylkill ; Dela- 

 ware ; Centre ; Allegheny ; Philadelphia ; Lackawanna ; Tioga. 



5. Populus grandidentata Michx. LargE-TooTHEd Aspen. (Man. 

 p. 310; I. F. /. 1/69. ) In rich woods, N. S. to Minn., N. J. and in the 

 AUeghenies to N. C. and Tenn. — Pennsylvania : Northampton ; 

 Chester ; Carbon ; Schuylkill ; Monroe ; Montgomery ; Frank- 

 lin ; Centre ; Delaware ; Allegheny ; Lancaster ; Tioga ; Lacka- 

 wanna. 



6. Populus dilatata Ait. Lombardy Poplar. (Man. p. 309. ) Com- 

 monly escaped from cultivation. Nat. of Eu. Pennsylvania ; Bucks ; 

 Lancaster ; Allegheny. 



7. Populus deltoides Marsh. Cottonwood. (Man. p. 309 ; I. F. 

 / ir72. ) In moist soil, especially along streams and lakes, Quebec to 

 the N. W. Terr., south to Fla., Colo, and N. Mex. — Pennsylvania : ERIE, 

 Presque Isle ; Lancaster. 



2. SALIX L. 

 A. Capsule glabrous, except for a few silky hairs in 5. fluviatilis. 

 Stamens 3-7. 

 Pedicels slender, three to five times as long as the glands. 

 Stipules and petioles glandless. i. S. nigra. 



Stipules and petioles prominently glandular. 2. 5. lucida. 



Pedicels about twice as long as the glands. 3. S.fragilis. 



Stamens 2. 

 Filaments pubescent at the base : bracts caducous. 

 Pedicels 1-3 mm. long at maturity. 

 Style manifest : leaf- blades mainly lanceolate. 3. S.fragilis. 

 Style wanting : leaf-blades linear or nearly so. 10. 5. interior. 

 Pedicels less than i mm, long at maturity. 

 Branches and branchlets not drooping : leaf-blades lanceolate. 



4. .S. alba. 

 Branches and branchlets drooping : leaf-blades linear-lanceolate or 

 nearly linear. 5. 5. Babylonica. 



Filaments glabrous : bracts persistent. 

 <i. Leaf-blades toothed. 

 Leaves with glabrous blades at maturity : capsules pedicelled. 

 Leaf-blades less than thrice as long as broad, glaucous beneath. 



6. 5. glaucophylla. 

 Leaf-blades over thrice as long as broad : green beneath. 



7. S. cordata. 

 Leaves with densely pubescent blades at maturity : capsules sessile. 



8. S. adenophylla. 



