abc<i f e 2 f KEY, BASED UPON LEAVES. 9 



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



NARROW LEAF CBAB (Pyrus angusti folia) . 

 V Lance-oblong, finely rugose ab., glaucous bn.; fr. a Hmall capsule with 



cotton-tufted seeds GLAUCOUS WILLOW (Halix 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 (Kymplocos tinctoria). 



t* 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). 



f 5 Ovate, cuneate to rounded b., acute to acuminate, strongly reticulate, 



whitish and often rusty bn. ; fr. capsule. 



BALSAM POPLAR (Populus balsamifera) . 



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

 % 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) . 

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



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



f* 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). 



f 11 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 l / 2 -3 in., cuneate b., rounded, obtuse or notched a.; fr. drupe- 

 like SWAMP HOLLY ( Ilex dccidua). 



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



drupe-like YAI:PO.\ ( flex vomitoria). 



e3 Suborbicular, iy z -3 in., rounded or obtuse b., abruptly acute or short ; -umi- 

 nate, finely crenate; petioles long and compressed laterally; fr. eap-iil<-. 



^TAKING ASP ( Populus tremuloides). 



e 4 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 niyra). 



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. 



SII.VKK I-.KI.I. TKKF: (. \fohrodendr on Carolinum). 

 e2 Coarsely dentate, broad-ovate to orbiculer; petioles 



