Trees or shrubs, with compound or lobed leaves, and usually unsymmetrical and often irregular flowers. Sepals and petals 4-5, both imbricated in the bud. Stamens 5-10, inserted on a fleshy disk which fills the bottom of the calyx-tube. Ovary 2-3-celled, with 1 or 2 ovules in each cell.

Synopsis Of The Genera

1. Stapliyle'a. Flowers perfect. Lobes of the coloured calyx, the petals, and the stamens, each 5. Fruit a 3-celled, 3-lobed, inflated pod. Leaves pinnately compound.

2. Acer. Flowers polygamous. Leaves simple, variously lobed, opposite. Calyx coloured, usually 5-lobed. Petals none, or as many as the sepals. Stamens 3-12. Fruit two 1-seeded samaras joined together, at length separating.

3. Negun'do. Flowers dioecious. Leaves pinnate, of 3 or 5 leaflets.

Fruit a double samara, as in Acer.

1. Staphyle'a

L. Bladder-Nut. S. trifo'lia, L. (American Bladder-Nut.) Shrub, 4-6 feet high. Leaflets 3, ovate, pointed. Flowers white, in drooping raceme's, at the ends of the branchlets. - Thickets and hill-sides.

2. Acer. Tourn. Maple

1. A. Pennsylvan'icum, L. (Striped Maple.) A small tree, 10-20 feet high, with light-green bark striped with dark lines. Leaves 3-lobed at the apex, finely and sharply doubly-serrate, the lobes taper-pointed. Flowers greenish, in terminal racemes, appearing after the leaves. Samaras large, with divergent wings. - Rich woods.

2. A. spieatum, Lam. (Mountain Maple.) A shrub or small tree, 4-8 feet high, growing in clumps in low grounds. Leaves 3-lobed, coarsely serrate, the lobes taper-pointed. Flowers greenish, appearing after the leaves, in dense upright racemes. Fruit with small widely-diverging wings.

3. A. sacchari'num, Wang. (A. saccharum, Marshall.) (Sugar Maple.) A fine tree, with 3-5-lobed leaves, breadth and length the same, dull above, a paler green underneath, the rather narrow sinuses rounded, and the lobes sparingly sinuate-toothed, the petioles without stipules. Flowers greenish-yellow, drooping on slender hairy pedicels, appearing at the same time as the leaves. Calyx fringed on the margin. Var. barbatum, Michx., has rather glossy leaves, mostly broader than long, 3-lobed, with very open rounded sinuses, and no stipules. Var. nigrum, Torr. and Gray, may be distinguished from the ordinary form by its paler and more pubescent leaves, the petioles with adnate foliaceous stipules. - Rich woods.

4. A. dasycar'pum, Ehrhart. (A. saccharinum L.) (White or Silver M.) Leaves deeply 5-lobed, the sinuses rather acute, silvery-white underneath, the divisions narrow, sharply-toothed. Flowers in erect clusters, greenish-yellow, appearing much before the leaves; petals none. Samara very large, woolly when young. River-banks and low grounds.

5. A. ru'brum, L. (Red M.) Leaves 3-5-lobed, the sinuses acute. Flowers red, appearing much before the leaves. Petals linear-oblong. Samara small and smooth, on drooping pedicels. A smaller tree than No. 4, with reddish twigs, and turning bright crimson in the autumn. - Swamps.

2. Negun'do

Mcench. Ash-leaved Maple. Box-Elder. N. aceroi'des, Moench. Calyx minute, 4-5-cleft. Petals none. Staminate flowers in rather dense clusters on slender pedicels, the pistillate ones in drooping racemes. Wings of the samaras incurved. - N. W., common. Also, Don valley near Toronto, and planted as a shade-tree.