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.

i. Leaves very glabrous both sides; fruit a prickly bur.

j. Leaves 3-5 inches long, very lustrous beneath; bark close, smooth, steel-gray. FAGUS, p. 93.

jj. Leaves 6-8 inches long, not lustrous beneath; bark fissured, brownish. CASTANEA, p. 95.