b c d 6 e 2 f KEY, BASED UPON LEAVES. 9 



f Lance-ovate, rounded or apiculate a.; fr. a small fit waxy-coated apple. 



NARROW LEAF CRAB (Pyrus angustifolia) . 

 f2 Lance-oblong, finely rugose ab., glaucous bn.; fr. a small capsule with 



cotton-tufted seeds GLAUCOUS WILLOW (Salix discolor). 



fs Lance-obovate, 4-6 in., cuneate b., acute or acuminate a., very lustrous ab., 

 thick and with short stems; fr. dry drupe. 



SWEET LEAF (Symplocos tinctoria). 



f* Rhombic-lanceolate to ovate, with long slender stems, cuneate to nearly 



rounded b., acuminate a.; a tree of the eastern foot-hills of the Rocky 



Mountains; fr. capsule. . .LANCE-LEAF COTTONWOOD (Populus acuminata). 



fs Ovate, cuneate to rounded b., acute to acuminate, strongly reticulate, 



whitish and often rusty bn.; fr. capsule. 



BALSAM POPLAR (Populus lalsamifera) . 



fe Heart-shaped, 3-8 in., with long round stems; fr. capsule; Ivs. 

 g Acuminate, whitish and often rusty bn. 



BALM-OF-GILEAD (Populus candicans). 

 g2 Obtuse to subacute a., hairy bn. and on stems. 



SWAMP POPLAR (Populus heterophylla ) . 

 t~ Ovate-oblong, 1-3 in., rounded or obtuse and more or less inequilateral b.; 



fr. coriaceous drupe PLANER-TREE (Planera aquatica) . 



fs Oblong, 2-4 in., acute or rounded both ends, lustrous and veins impressed 

 ab., obscurely crenate-serrate ; a very small tree or shrub of the southern 



states; fr. drupe-like YELLOW BUCKTHORN (Rhamnus Caroliniana) . 



f Obovate, 4-8 in., obtuse or acute b., acute or acuminate a., regularly 



crenate; fr. an acorn Cow OAK (Quercus Michauxii). 



fio Deltoid-ovate, truncate or wide cordate b., acute or short-acuminate, stems 

 long and laterally compressed; fr. capsule. 



COTTONWOOD (Populus deltoides). 



fn Orbicular-ovate, 1-2 in., rounded to subcordate b., obtuse to acute or 

 apiculate a., glabrous and fragrant; fr. drupe. 



PERFUMED CHERRY (Prunus Mahaleb). 

 d 7 Margin crenate or crenulate ; Ivs. 



e Lance-obovate, l%-3 in., cuneate b., rounded, obtuse or notched a.; fr. drupe- 

 like SWAMP HOLLY ( Ilex decidua) . 



e2 Oblong, 1-2 in., thick, evergreen; fr. a bright red drupe-like berry; fr. 



drupe-like YAUPON (Ilex vomitoria) . 



e3 Suborbicular, l%-3 in., rounded or obtuse b., abruptly acute or short acumi- 

 nate, finely crenate; petioles long and compressed laterally; fr. capsule. 



QUAKING ASP (Populus tremuloides) . 



e* Broad-deltoid or rhombic, blade commonly wider than long, cuneate to 

 truncate b.. short acuminate or acute a.; petioles long, laterally com- 

 pressed; fr. capsule; branches 



f Spreading BLACK POPLAR (Populus nigra). 



f2 Strictly upright LOMBARDY POPLAR (Populus dilatata) . 



d Margin dentate, 



e Finely dentate, mostly oblong, acute or obtuse b., acuminate a., with prominent 

 arcuate veins; fr. dry winged drupe. 



SILVER-BELL TREE (Mohrodendron Carolinum). 

 e- Coarsely dentate, broad-ovate to orbiculer; petioles 



