Trees or shrubs, with a milky or resinous juice, and alternate leaves without dots or stipules. Sepals, petals and stamens, each 5. Fruit a 1-seeded drupelet. The petals and stamens inserted under the edge of a disk which surrounds the base of the ovary. The only genus is Rhus
1. R. typh'ina, L. (Staghorn Sumach.) A small tree, 10-30 feet high, with densely soft-hairy branches and stalks. Flowers greenish-white, polygamous, forming a terminal thyrse. Fruit globular, covered with crimson hairs. Leaves pinnate, leaflets 11-81. oblong, lanceolate, serrate, pointed. - Dry hill-sides.
2. R. glabra, L., (Smooth S.) is smooth, and seldom exceeds 5 feet in height.
8. R. Toxicoden'dron, L. (Poison Ivy. Poison Oak.) Shrub about a foot high, smooth, often climbing by rootlets. Leaves 3-foliolate, leaflets rhombic-ovate, notched irregularly. Flowers polygamous, in slender axillary panicles. Plant poisonous to the touch. Var. radi'cans, L., has the leaves entire, and climbs high.
4. R. venenata, DC. (Poison Elder.) A tall shrub, smooth or nearly so. Leaves odd-pinnate; leaflets 7-13, obovate-oblong, entire. Greenish-white flowers as in No. 3. - Swamps.
5. R. Canadensis, Marsh. (Fragrant S.) (E. aromat-ica, Ait.) A shrub 2-3 feet high, or more, with 3-foliolate leaves, sweet-scented when crushed, and catkin-like spikes of pale yellow flowers appearing before the leaves. - Dry rocky banks. Var. trilobata, with small leaflets and an unpleasant odour, is rather common in the North-West.