Trees or shrubs abounding in resinous or caustic juice. Leaves simple, trifoliolate or imparipinnate. Flower inconspicuous, in axillary or terminal panicles, polygamous. Calyx small, 4- to 6-partite; lobes equal, imbricate. Petals 4 to 6, spreading. Stamens 4 to 6 or 10. Fruit a 1-seeded berry. A genus of about 120 species from the warmer parts of the whole world. The name is derived from a Celtic word signifying red, the colour of the fruits of some species. The number grown for ornamental purposes is very limited. R. Coriaria furnishes the Sumach of commerce.

1. R. Cotinus. Wig Tree or Venetian Sumach. - A shrub about 6 feet high with simple glaucous entire obovate or rotundate leaves narrowed at the base and on long petioles, and a feathery inflorescence. The flowers are small, but the transformation of some of the pedicels and hairs into white feathery awns imparts a very peculiar appearance to the inflorescence. This and the next are the only species commonly cultivated in this country. A native of the South of Europe. It furnishes the dye called Young Fustic.

2. R. typhina. Stag's-horn Sumach. - This is the commonest species in gardens, and spreads very rapidly by suckers. It is a handsome shrub or small tree with large hairy pinnate leaves and densely hairy thick shoots. Leaflets 9 to 25, glaucous beneath, sessile, lanceolate, acuminate, deeply serrate, the veins prominent below and as well as the main rachis clothed with fulvous hairs. Flowers greenish yellow or red, in dense clusters. A native of North America, eminently suited for planting near the sea.

3. R. glabra, syn. R. elegans. - Similar to the last, with glabrous somewhat glaucous leaves, whitish beneath. The berries are bright red, and a variety in which they are unusually brightly coloured is called coccinea. A native of North America.

R. succedanea and R. vernix are Japanese species of recent introduction with handsome pinnate leaves. R. Toxicodendron, Poison Ivy. is a very venomous North American species, half-scandent in habit, with trifoliolate leaves and white berries.