Bark.—Trunk and branches mottled gray, roughish with round spots; branchlets light brown; season's shoots reddish at first, turning later to gray, thickly beset with rough yellowish warts; leaf-scars prominent, triangular.
Buds and Leaves.—Buds small, roundish. Leaves pinnately compound, alternate; rachis abruptly widened at base; leaflets 5-13, opposite, short-stalked except the odd one, 2-3 inches long, 1-2 inches wide, smooth, light green and mostly glossy when young, becoming dark green and often dull, obovate to oval or ovate; entire, often wavy-margined; apex acute, acuminate, or obtuse; base mostly obtuse or rounded; veins prominent, often red; stipules none.
Inflorescence.—Early in July. Near the tips of the branches, in loose, axillary clusters of small greenish flowers; sterile, fertile, and perfect flowers on the same tree, or occasionally sterile and fertile on separate trees; calyx deeply 5-parted, divisions ovate, acute; petals 5, oblong; stamens 5, exserted in the sterile flowers; ovary globose, styles 3.
Fruit.—Drupes about as large as peas, smooth, more or less glossy, whitish; stone ridged; strongly resembling the fruit of R. Toxicodendron (poison ivy).
Horticultural Value.—No large shrub or small tree, so attractive as this, does so well in wet ground; it grows also in any good soil, but it is seldom advisable to use it, on account of its noxious qualities. It can be obtained only from collectors of native plants.
Note.—This sumac has the reputation of being the most poisonous of New England plants. The treacherous beauty of its autumn leaves is a source of grief to collectors. Many are seriously affected, without actual contact, by the exhalation of vapor from the leaves, by grains of pollen floating in the air, and even by the smoke of the burning wood.
It is easily distinguished from the other sumacs. The leaflets are not toothed like those of R. typhina (staghorn sumac) and R. glabra (smooth sumac); it is not pubescent like R. typhina and R. copallina (dwarf sumac); the rachis of the compound leaf is not wing-margined as in R. copallina; the panicles of flower and fruit are not upright and compact, but drooping and spreading; the fruit is not red-dotted with dense crimson hairs, but is smooth and whitish. Unlike the other sumacs, it grows for the most part in lowlands and swamps.
In the vicinity of Southington, southern Connecticut, Rhus copallina is occasionally found with a trunk 5 or 6 inches in diameter (C. H. Bissell).
