Rhus L. (1753), in the family Anacardiaceae. Sumac, Sumach or Taaibos. Contains around 200 species, found in North and Central America, southern Europe, Africa, and Asia. Description Trees to 10m, or shrubs. The leaves are alternate, deciduous or evergreen, pinnate with up to 15 leaflets, or simple.
The flowers are small, white or green, unisexual or bisexual, in large, branched heads, usually at the tips of the branches. Sepals 5, joined at the base; petals 5. Stamens 5. Ovary superior, with 1 cell and 3 styles. Pollination is by small insects. The fruits are 1-seeded, often with thin, red flesh. Key Recognition Features The alternate, usually pinnate leaves and usually hairy inflorescence. Evolution and Relationships Rhus is the largest genus in the family Anacardiaceae. Poison oak and poison ivy are now again separated in the genus Toxicodendron, as they were by Miller in 1768. Ecology and Geography In woods in southern Europe and South Africa, in Asia southwards to northern Australia, and in North America. Comment Many species are grown for their fine autumn colour. The fruit of the stag’s horn sumach, R. typhina L. may be used to make a cordial. The leaves of several species are used in tanning, and others are a valuable source of Chinese laquer and copal varnish. Photographs:
Rhus punjabensis, Autumn colour
Rhus trichocarpa |
