=a.= Fruit small ( in.), fleshy, drupe-like, with a striate stone; limbs branching horizontally, often descending 46. _Nyssa._

=a.= Fruit a black, juicy berry (1/3- in.), with about 3 seeds 20. _Rhamnus._

=a.= Fruit an ovoid dry drupe ( in.); leaves sweet-tasting 59. _Symplocos._

=a.= Fruit an apple-like pome (Quince) 37. _Pyrus._

=b.= Wood soft; both kinds of flowers in catkins in spring; with either stipules or stipular sears 91. _Salix._

=b.= Wood hard; leaves thick; fruit an acorn 88. _Quercus._

=c.= Fruit a 2-4-seeded small berry; juice not milky 20. _Rhamnus._

=c.= Fruit large, orange-like in size and color when ripe; juice milky 77. _Maclura._

=c.= Fruit small, black when ripe, cherry-like; juice milky 54. _b.u.melia._

=d.= Aromatic; berries dark blue on red stalks 68. _Persea._

=d.= Not aromatic; leaves nearly 1 ft. long; flowers large and solitary. 1. _Magnolia._

=d.= Not aromatic; leaves 1-4 in. long; flowers very small; fruit small dark-colored berries, with 2-4 seeds 20. _Rhamnus._

=d.= Not aromatic; flowers large, in showy cl.u.s.ters. (=e.=)

=e.= Leaves 5 in. or more long 52. _Rhododendron._

=e.= Leaves less than 4 in. long 51. _Kalmia._

=f.= Leaves decidedly aromatic, usually somewhat irregularly lobed, margin entire, base tapering 69. _Sa.s.safras._

=f.= Leaves usually deltoid, sometimes heart-shaped with serrate margin and gummy buds, rarely palmately lobed.

All have either the petiole flattened sidewise, the leaf-blade densely silvery-white beneath, or gummy aromatic buds 92. _Populus._

=f.= Leaves broadly heart-shaped; margin entire; small tree with abundance of red flowers in early spring; fruit a pea-like pod. 32. _Cercis._

=f.= Leaves not as above given. (=g.=)

=g.= Leaves broadly heart-shaped, with a serrate margin and a petiole about as long as the blade, sometimes longer; base of leaf not oblique 4. _Idesia._

=g.= Leaves broadly heart-shaped, those on the suckers much lobed; base not oblique; margin serrate; juice milky; bark very tough. (=l.=)

=g.= Leaves broadly heart-shaped, with an oblique base; margin regularly serrate; juice not milky 11. _Tilia._

=g.= Leaves slightly if at all heart-shaped at base, usually somewhat oblique, with neither milky juice nor lobes. (=j.=)

=g.= Leaves decidedly and quite regularly lobed. (=h.=)

=h.= Leaves with 3-5 large lobes, the margin entire or slightly angulated. 10. _Sterculia._

=h.= Leaves star-shaped, with 5-9 pointed, serrate lobes.

(=i.=)

=h.= Leaves large, irregularly margined; leaf-stem covering the bud; large tree 80. _Plata.n.u.s._

=h.= Plant quite th.o.r.n.y; fruit berry-like, ending in a conspicuous spreading calyx; small trees or shrubs with apple-like blossoms. 38. _Crataegus._

=h.= Leaves with a tapering base; small tree, almost a shrub, with large Hollyhock-like flowers; plant not th.o.r.n.y 9. _Hibiscus._

=i.= Large tree, with fruit 1 in. in diameter, dry, rough, hanging on a long stem 41. _Liquidambar._

=i.= Small tree with few branches and the trunk usually quite p.r.i.c.kly; fruit berry-like in large cl.u.s.ters 44. _Aralia._

=j.= Fruit small berries, with 3 flattened seeds, in cl.u.s.ters in the axils of the leaves, which are decidedly 3-ribbed from the base 21. _Hovenia._

=j.= Fruit small drupes, with 1 seed, either solitary or in pairs in the axils of the leaves. (=k.=)

=k.= Plant without p.r.i.c.kles; leaves decidedly oblique at base 76. _Celtis._

=k.= Plant with p.r.i.c.kles; leaves narrow, decidedly 3-ribbed, and 2-ranked on green twigs 22. _Zizyphus._

=l.= Fruit not very edible; leaves rough above, very hairy below, on some of the twigs opposite 79. _Broussonetia._

=l.= Fruit edible; leaves not very hairy, never opposite 78. _Morus._

=m.= Leaves of 3 entire-edged leaflets; fruit a pea-like pod 28. _Laburnum._

=m.= Leaves of 3 quite regularly serrate, transparent-dotted leaflets 13. _Ptelea._

=m.= Leaves once or twice pinnate; the leaflets entire.

(=s.=)

=m.= Leaves once or twice pinnate; the leaflets with margins more or less serrate or notched. (=n.=)

=n.= Leaves irregularly once to twice, in one case three times, pinnate. (=r.=)

=n.= Leaves regularly once pinnate. (=o.=)

=o.= Leaves less than 1 ft. long, on a small, quite p.r.i.c.kly plant; fruit very small pods ( in. long) 12. _Xanthoxylum._

=o.= Leaves less than 1 ft. long; leaflets 3 in. or less long; fruit bright-colored, berry-like pomes in cl.u.s.ters, persistent through the autumn; plant not th.o.r.n.y; branches not heavy-tipped. 37. _Pyrus._

=o.= Leaves usually larger on the small tree or almost a shrub; juice in most cases milky; branches heavy-tipped 27. _Rhus._

=o.= Leaves 1-2 ft. long; leaflets 3 in. or more long; fruit a bony nut with green fleshy coat; large trees.

(=q.=)

=o.= Leaves very large, 2 ft. or more long on the rapid-growing branches; branches heavy-tipped; odor of bruised leaves quite strong; leaflets 15 or more in number; large trees; juice not milky. (=p.=)