76 



METROPOLITAN PARK FLORA. 



on hill-tops, the long pistillate catkins conspicuous by the end 

 of April : — B* and M, common : — 8 and BB, frequent. 



S. humilis X discolor, Bebb. 



Same habitat as the parent species. M*, rare ; near S. 

 Reservoir. 



S. humilis, Marsh. Low Willow. Prairie Willow. 



Dry or wet ground. B*, Chestnut Run path : — M, fre- 

 quent : — S*-, occurs. 



S. tristis, Ait. Dwarf Gray Willow. 



Sandy places, gravelly fields, low thickets and roadsides. 

 B *, rare ; N. slope of Rattlesnake Hill ; W. of Sawcut Notch : 

 — M*, occasional: — S*, Happy Valley. 



S. sericea, Marsh. Silky Willow. 



Low ground. B *, rare ; Chestnut Run path, E. of Han- 

 cock Hill : — M *, rare ; N. side of Spot Pond. 



5. petiolaris, Smith. 



Low ground. M*, rare ; fields round Spot Pond ; meadow, 

 N. of Bear Hill ; S. end of S. Reservoir. 



5. purpurea, L. Purple Willow. 



Adv. from Eu. in low ground. M, one tree in low land, S. 

 W. of Pine Hill. 



S. cordata, Muhl. Heart-leaved Willow. 



Wet places, along streams and by damp roadsides. B, fre- 

 quent : — M, occasional. 



5. cordata X sericea, Bebb. 



Low ground. B, swamp, N. E. of Hawk Hill. 

 S. myrtilloides, L. 



Cold bogs. M, occasional. 



POPULUS, Tourn. Poplar. Aspen. 

 P. tremuloides, Michx. Aspen. 



Woods and roadsides ; the most widely distributed tree in 

 North America. B, occasional : — M, common. 



