15 
l 
Leaf margins strongly indented in 2 or 4 places, these in¬ 
dentations variable but usually reaching at least a third 
of the distance to the base of the blade. Fruit with a 
flat wing—Maple, 174 
15 Leaves usually with only one indentation and this at the 
base (i. e. leaves heart-shaped), occasionally some leaves 
with one or two angles or shallow indentations on the 
sides. No small marginal teeth—Ifl 
10 Fruit 12 to 18 inches long, cylindrical—Catalpa, 104 
16 Fruit globular or top-shaped. Cult.—Paulownia, Paulovmia 
tomentosa (Thunb.) Steud. 
17 Prominent veins at the base of the blade 5 or more—18 
17 Prominent veins at the base of the blade 3 (rarely 5)—10 
18 Leaves strongly star-shaped. Southern N. E.—Sweet Gum, 
Red Gum, Alligator-wood, Liquidambar, Liquidambar 
Styraciflua L. 
18 Leaves symmetrically heart-shaped, margins entire. Cult.— 
Redbud, Judas-tree, Cere in canadensis L. 
18 Leaves unsymmetrically heart-shaped, margins toothed— 
Linden, 186 
19 Leaves broader than long, with strong angles or shallow in¬ 
dentations—Buttonwood, Buttonball-tree, Plane-tree, Plata- 
nm occidental in L. 
10 Leaves longer than wide—20 
20 Leaf length not twice the width. Juice milky—Mulberry, 
140 
20 Leaf length not twice the width. Juice not milky. Base 
of blade unsymmetrical—Linden, 186 
20 Leaf length more than twice the width. Juice not milky— 
Hackberry, Sugarberry, Nettle-tree, One-berry, Ccllis occiden - 
tali* L. 
21 Margins either wavy, toothed, incised, or lobed—33 
21 Margins entire, without any of the above characters—22 
22 Twigs and bark aromatic when bruised. Usually some of 
the leaves variously lobed—Sassafras, Sami fra* variifolium 
(Salisb.) Ktze. 
22 Twigs and bark not aromatic. None of the leaves lobed—23 
23 Leaves thick, smooth and evergreen—24 
