SALICACEAE 26l 



L. I., there rare or wanting; always increasing northward and at 

 higher elevations; rare on the coastal plain. 



DICOTYLEDONES 



SAURURACEAE 



1. Saururus L.* 



1. S. cernuus L. In swamps and shallow water: R. I. to Fla., 



S. Ont., Minn, to Tex. 



Conn. Mostly in the coastal counties. 



N. Y. L. I., S. I., Bronx and Westchester counties. 



N. J. Throughout, except in the pine-barrens. 



Pa. Chester and Delaware counties. 



SALICACEAE 



Bracts of the flowers more or less cut and fringed; disk cup-shaped; 



winter buds with several scales. I. Populus. 



Bracts of the flowers entire; disk of 1 or 2 glands; winter buds with 



1 scale. 2. Salix. 



i. Populus L. 



Petioles round or channeled, scarcely or not at all flattened 

 laterally. 

 Leaves densely white-tomentose beneath, lobed or coarsely 



toothed. 1. P. alba. 



Leaves glabrous or nearly so when mature, crenate or crenu- 

 late. 

 Leaves densely tomentose when young; capsules Iong- 



pedicelled. 2. P hctcrophylla. 



Leaves not tomentose when young, capsules short- 



pedicelled. 3. P. candicans. 



Petioles strongly flattened laterally. 



Leaves broadly deltoid, abruptly acuminate; stigma lobes 

 dilated. 

 Young leaves pubescent; capsules nearly sessile. 4. P. nigra. 



Leaves glabrous; capsules pedicelled. 5. P. delloides. 



Leaves broadly ovate to suborbiculate; stigma lobes filiform. 



Leaves coarsely sinuate-dentate. 6. P. grandidentaia. 



Leaves crenulate-denticulate to entire margined. 7. P. tremuloides. 



i. P. alba L. In yards and along roadsides: N. B. to Ont. and 

 Va. Introduced from Eur. and As. 

 Locally abundant as an escape. 



2. P. heterophylla L. In rich wet soil: Conn, to N. J. and Ga., 



west to Mo., Ark. and La. 



* See footnote page 76. 



