156 



leaves simple, etc.— Continued. 

 Branches unarmed : 



Leaves evergreen — ihicMsh, leathery ; densely woolly or minutely downy on 

 the under surface : 

 a. Margin more or less indented or sometimes entire : 

 Fruit an acorn : 



Leaves 1 to 2 inches long 69 



Leaves 2 to 3| inches long 72 



Fruit a tailed seed ; leaves ^ to 1^ inches long 51 



h. Margin entire and rolled back ; fruit a tailed seed 50 



Leaves deciduous, ihin, not leather}/: 

 Margin entire; leaves very narrow, less than one-quarter of an inch * 

 wide: 



Fruit a long (6 to 12 inches) pod 61 



Margin variously indented, but sometimes entire, or nearly so; leaves 

 more than one-quarter ol" an inch wide : 

 a. With fine (not prickle or bristle pointed) teeth: 



Bark bitter; fruit (seed) borne in deciduous catkins, and when 

 mature, cottony: 

 Leaves broad, triangle-shaped, or ovate (in 84) ; branches often 



angled; buds resinous: Poplars: 

 Triangle-shaped: 



Smooth on both sides 82(86) 



White-downy on the under surface 83 



Ovate (exceptionally uarrow,lance-shaped); smooth both sides. 84 

 Leaves narrow, lance shaped; branches round; buds not resin- 

 ous : WiLLOAVS: 



Less than i; an inch wide, mostly ^ to i of an inch 80 



More than ^ an inch wide: 



Pale or whitish on the uuder surface : 



Leaf stems with glands at the base of the blade 79 



Leaf-stems without glands 78 



Brownish downy on the under surface 81 



Bark not bitter : 



Separating (on trunk) into thin papery layers or sheets; seeds 

 in a deciduous scaly catkin and with wings: 

 Birches: 



Coppery-yellow ; leaves 1 to 1^ inches long 74 



Chalky-white; leaves 2 to 3^ inches long 73 



Not separating into layers or sheets; fruit fleshy, or a winged 

 seed in a persistent catkin : 

 . Leaves unequal sided (unsymmetrical), mostly entire, but occa- 

 sionally with small teeth : 

 Very rough on the upper surface; fruit cherry-like, dry, 



sweet 63 



Smooth above, hairy on under side ; fruit a flat winged seed — 



samara ; belongs under '^coarse teeth" 62 



Leaves equal-sided (symmetrical) and always foothed on the mar- 

 gin : 



Rough ; freshlj'-woundcd bark exuding a milky juice 64 



