small, pale brown cone.

THUJA, p. 31. ee. Twigs essentially terete; leaves of two kinds, either scale-like, or else awl-shaped, often both kinds on the same branch, not decurrent on the stem; fruit berry-like, bluish. JUNIPERUS, p. 33. dd. Leaves alternate or spirally-whorled. e. Leaves flattened, soft to the touch.           f. Leaves 1/2-1-1/4 inches long, sessile, aromatic; cones 2-4 inches long; bark of trunk with raised blisters containing resin. ABIES, p. 27. ff. Leaves seldom over 1/2 inch long, short-petioled, not aromatic; cones about 3/4 inch long; bark of trunk without raised blisters. TSUGA, p. 29. ee. Leaves 4-sided, harsh to the touch. PICEA, p. 18. bb. Leaves broad and flat. c. Leaves alternate or clustered, never opposite nor whorled. d. Margin of leaves entire or only slightly undulate. e. Leaves heart-shaped or rounded; fruit a legume. 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. 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. NYSSA, p. 209. ii. Leaves thin, long-pointed, not lustrous above, clustered at the ends of the branches. CORNUS, p. 202. dd. Margin of leaves serrate, toothed or lobed. e. Margin of leaves serrate to toothed. f. Branches armed with stiff, sharp thorns. 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. TILIA, p. 201. hh. Leaf-blades 1-1/2 - 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. CELTIS, p. 131. ii; Leaves thick, coarsely and doubly serrate; fruit a samara, ripe in spring. ULMUS, p. 122. gg. Base of leaves essentially symmetrical. h. Teeth coarse, 2-5 per inch of margin.