SALICACEAE (WILLOW FAMILY) 



2 a Leaves fragrant when crushed, not densely hairy when 



young, apex usually tapering, pointed 



BALM-OF-GILEAD. (P. cdndicam.) 



b Leaves not fragrant when crushed, densely hairy when 

 young, apex blunt, the basal lobes often overlapping 



DOWNY POPLAR. (P. heterophylla.) 



3 a All leaves white-woolly beneath, usually somewhat lobed 



WHITE POPLAR. (P. dlba*) 

 b All leaves not white- woolly beneath or not lobed 4 



4 a Leaves more or less triangular 5 



b Leaves ovate to rounded 6 



5 a Leaves 2-3 in. broad; branches erect or ascending 



LOMBARDY POPLAR. (P. itdlica*) 

 b Leaves 3-7 in. broad ; branches more or less spreading 



COTTONWOOD. (P. deltoldes.) 



6 a Leaves ovate, usually with large, irregular teeth, some- 



times hairy beneath 



LARGE-TOOTHED ASPEN. (P. grandidentdta.) 

 b Leaves roundish-heart-shaped, 1-3 in. broad, with com- 

 paratively small teeth.AMERiCAN ASPEN. (P. tremuloldes.) 

 2 SALIX. 



1 a Mature leaves shining on both sides, not hairy, ovate 



to lanceolate 2 



b Mature leaves not shining on both sides 3 



2 a Aments appearing with the leaves ; native tree or shrub 



SHINING WILLOW. (S. lucida.) 



b Aments appearing after some leaves are completely de- 

 veloped ; cultivated tree or shrub 



BAY-LEAVED WILLOW. (S. pentdndra*) 



3 a Mature leaves green on both sides, not conspicuously 



lighter beneath, %-% in. broad; branchlets pale yel- 

 low ; a tree BLACK WILLOW. (S. nlgra.) 



b Mature leaves conspicuously lighter colored beneath.. 4 



4 a Small shrub 1-2 ft. high; leaves woolly beneath 



DWARF GRAY WILLOW. (S. tristis.) 

 b Shrubs or trees not completely as in a 5 



5 a Tree with leaves ^4-% in. broad, 3-7 in. long, very pale 



beneath ; branchlets slender and drooping 



WEEPING WILLOW. (S. babylonica.) 

 b Trees or shrubs not completely as in a 6 



6 a Stipules comparatively large, often % in. or more broad, 



persistent; average leaf 2-4 in. long, l /2-i in. broad, 

 often rounded at base 



HEART-LEAVED WILLOW. (S. corddta.) 

 b Stipules not persistent, either wanting or only on young 



branchlets 7 



140 



