A KEY TO THE BLACK OAK GROUP
A. Leaves narrow, willow-like; Southern tree. Willow Oak. AA. Leaves oval, with deeply-cleft margins. B. Acorn cups, shallow, broader than high. C. Tree pyramidal, twigs with pin-like spurs. Pin Oak. CC. Tree spreading; acorns large, in shallow saucers. Red Oak. BB. Acorn cups as deep as broad. C. Leaves thin, smooth, deeply cut; acorn cup drawn in at the top. Scarlet Oak. CC. Leaves leathery, rough, with rusty hairs beneath; acorn cup not drawn in at the top. Black Oak.
A KEY TO THE ELMS
A. Twigs smooth, not hairy-coated. B. Bark of branches not corky-ridged. American Elm. BB. Bark of branches corky-ridged. Winged Elm. Wahoo. AA. Twigs hairy-coated. B. Bark of branches corky. Cork Elm. Rock Elm. BB. Bark of branches not corky; buds coarsely hairy. Slippery Elm.
A KEY TO THE MAPLES
A. Leaves simple. B. Bloom before the leaves open; seeds ripe in May. C. Flowers red; leaves pale beneath, with three triangular lobes. Red Maple. CC. Flowers greenish; leaves pale beneath, deeply cleft, with long, spiny lobes. Silver Maple. BB. Bloom after the leaves open; seeds ripe in autumn. C. Leaves wider than long; lobes spiny-tipped. D. Lining of leaves, pale; keys joined at acute angle. Sugar Maple. DD. Lining of leaves, not pale; keys joined at wide angle. Norway Maple. CC. Leaves circular, lobed; tree prostrate. Vine Maple. CCC. Leaves about as wide as long; trees small. D. Bark striped with white lines; flowers and seeds in dense, pendant clusters. Striped Maple. DD. Bark not striped; flowers and seeds in pendant clusters. Mountain Maple. AA. Leaves compound, of 3 to 7 leaflets. Ash-leaved Maple. Box Elder.
A KEY TO THE WILLOWS
A. Twigs long, drooping. Weeping Willow. AA. Twigs erect. B. Leaves white beneath. C. Twigs yellow in spring; leaves narrow. Golden Osier Willow. CC. Twigs reddish in spring; leaves broad. Pussy Willow. BB. Leaves not white beneath; heart-shaped frill at base of leaf stem. Black Willow.
A KEY TO THE LOCUSTS
A. Leaves simple; flowers rosy. Redbud. AA. Leaves compound. B. Trees thorny. C. Thorns simple, paired, at bases of leaves; pods small, thin. Black Locust. CC. Thorns often branched, clustered; pods large, curved. Honey Locust. BB. Trees not thorny. C. Pods thick; limbs clumsy; leaves twice compound. Kentucky Coffee Tree. CC. Pods thin, small; limbs not clumsy; leaves once compound. Yellow-wood. Virgilia.