Rhus

Collier's New Encyclopedia (1921)

in botany, a genus of Anacardiaceæ. Leaves simple or compound. Flowers in axillary or terminal panicles, bisexual or polygamous. Calyx small, persistent, five-partite; petals five: stamens five; ovary one-celled, sessile; fruit a dry drupe, with one exalbuminous seed. Nearly 100 species are known. Most are shrubs, from 6 to 10 feet high. They exist in all the continents. The leaves of R. coriaria, the hide or elmleaved sumach of the S. of Europe, are used for tanning morocco leather. In the Himalayas those of R. cotinus are similarly employed. The fruit of the former was given in dysentery. In India, R. parviflora, R. semialata, R. succedanea, are used medicinally. Exudations from incisions in the bark of R. succedanea and R. vernicifera yield the varnish used in Japanese and Chinese wickerwork. The former produces astringent galls, and its seeds yield a kind of wax; as do also those of R. wallichii and the Japanese R. vernix. The juice of the latter species blisters the skin. The Turks used the acid fruits of R. coriaria to sharpen their vinegar. The plant yields sumach. The bark of R. glabrum is a febrifuge, and is employed as a mordant for red colors. R. metopium, a Jamaica plant, yields a medicinal gum. R. toxicodendron (used in pharmacy as a topical irritant) and R. venenata, American species, are poisonous, nor is any of the genus very safe. These two species are called indifferently poison oak, poison ivy, poison sumac, and more rarely mercury. The wood of R. collinus is employed for inlaid and cabinet work.