b 3 Margin of leaf more or less deeply lobed 



c 1 Leaf lobes rounded at the tips Oak, p. 14. 



c 2 Leaf lobes pointed at the tips, often bristle-pointed, 

 more or less serrate or toothed 

 d 1 Leaf lobes very coarsely toothed 



e 1 Lobes few, large, not bristle-tipped; bark 



light green or white, scaly Sycamore, p. 109. 



e 2 Lobes several, smaller, often bristle-tipped; 



bark not greenish or white Oak, p. 14. 



d 2 Leaf lobes finely toothed 



e 1 Twigs more or less thorny Hawthorne, p. 125. 

 e 2 Twigs not thorny Mulberry, p. 107. 



Leaves compound, i. e., divided into leaflets 

 a 1 Leaves opposite 



b 1 Leaves pinnately compound; fruit dry, winged; buds small 



c 1 Leaflets 7 to 9, not coarsely toothed; winged fruits 



single, paddle-shaped Ash, p. 15. 



c 2 Leaflets 3 to 5, coarsely toothed; winged fruits 



double, not paddle-shaped Boxelder, p. 15. 



b 2 Leaves palmately compound; fruit a large, dry bur; buds 



very large Buckeye and Horsechestnut, p. 15. 



a 2 Leaves alternate 



b 1 Leaves pinnately compound 



c 1 Branches with low thorns in pairs; flowers white, 

 large, very fragrant Black Locust, p. 127. 



c 2 Branches not thorny; flowers inconspicuous, not fra- 

 grant 

 d 1 Leaflets 11 to 41, large or small, the largest 

 usually at the base of the leaf, upper leaflets 

 becoming gradually smaller towards the tip of 

 the leaf 

 e 1 Leaflets large, 3 to 5 inches long, entire ex- 

 cept for a few coarse teeth at the base 



Tree of Heaven, p. 134. 



e 2 Leaflets smaller, usually about or less than 



3 inches long, usually finely toothed along 



the whole margin 



f 1 Trunk and branches armed with simple 



or branched thorns Honey Locust, p. 129. 



f 2 Trunk and branches not thorny 



g 1 Terminal leaflet usually missing; 

 leaflets 1 inch or more wide, usually 

 soft-hairy and aromatic 



Walnut, p. 13. 

 g 2 Terminal leaflet usually present; 

 leaflets less than 1 inch wide, 

 smooth, not aromatic 



Mountain Ash, p. 115. 



d 2 Leaflets 5 to 11, terminal leaflet often much 



larger than the lateral leaflets Hickory, p. 14. 



b 2 Leaves twice-pinnately compound 



c 1 Tree with large coarse thorns; bark dark brown or 

 reddish, smooth or pebbly; leaves 6 to 12 inches long, 

 leaflets oval, usually less than 1 inch long 



Honey Locust, p. 129. 



c 2 Tree not thorny; bark very rough and furrowed, 

 bright, reddish brown, more or less scaly; leaves 1 

 to 4 feet long, leaflets about 2 inches long, broadly 

 ovate Kentucky Coffee Tree, p. 131. 



—12— 



