e. Leaves heart-shaped or rounded; fruit a legume 
eth A te deshhemnanstaneis Daa tebe ATE Seta ener ‘CERCIS, p. 167. 
ee. Leaves oval, ovate or obovate; fruit not a legume. 
f. Branches armed with stout, straight spines; fruit 
large, orange-like............ MACLURA, p. 133. 
ff. Branches without spines; fruit small, not orange- 
like. 
g. Fruit an acorn.............. QUERCUS, p. 96. 
gg. Fruit a drupe or berry. 
h. Twigs spicy-aromatic when bruised; leaves of 
many shapes on the same branch............ 
Be een ee ee SASSAFRAS, p. 139. 
hh. Twigs not spicy-aromatic; leaves not of many 
shapes on the same branch. 
i. Leaves thick, abruptly pointed, very lustrous 
above, not clustered at the ends of the 
branches. 42228466. sea saree NYSSA, p. 200. 
ii. Leaves thin, long-pointed, not lustrous 
above, clustered at the ends of the branches 
ee CORNUS, p. 202. 
dd. Margin of leaves serrate, toothed or lobed. 
c. Margin of leaves serrate to toothed. 
f. Branches armed with stiff, sharp thorns......... 
whink Bia Cea Ag haienomahwe ke 8 CRATAEGUS, p. 151. 
ff. Branches not armed. 
g. Base of leaves decidedly oblique. 
h. Leaf-blades about as long as they are broad, 
heart-shaped................4. TILIA, p. 2or. 
hh. Leaf-blades 114-2 times as long as they are 
broad, oval to ovate. 
i. Leaves thin, coarsely but singly serrate; 
fruit a globular drupe, ripe in autumn...... 
Hui aoedaene nora dae were ew nas CELTIS, p. 131. 
ii, Leaves thick, coarsely and doubly serrate; 
fruit a samara, ripe in spring.............. 
Siihaby tetraacetate cris Sates Siuiatan sea ULMUS, p. 122. 
gg. Base of leaves essentially symmetrical. 
h. Teeth coarse, 2-5 per inch of margin. 
i, Leaves very glabrous both sides; fruit a 
prickly bur. 
— XxII — 
