rhodiola

a genus of dioecious perennial herbs of the family Crassulaceae. The thick stems have alternate flat or almost cylindrical sessile leaves. The unisexual, mostly tetramerous flowers are various shades of yellow and red and are gathered in corymbiform inflorescences. The fruit is composed of four follicles.

There are about 50 species, distributed in the temperate belt of the northern hemisphere, mainly in the mountains of Asia. The USSR has about 20 species, growing mostly in the alpine belt and tundra near the glaciers and on rocky slopes, cliffs, lawns, and riverbanks. The roseroot (R. rosea), which has yellow flowers and reddish fruits, is found in the northern European USSR, the Carpathian Mountains, the Urals, the Altai, southeastern Siberia, the mountains of Kazakhstan, and the Far East. It is a medicinal plant. A liquid extract from the underground parts of the plant and the substance rhodosine obtained from the extract are used to increase working capacity and to treat exhaustion, insomnia, and headache. The roseroot, R. algida, and R. heterodonta are grown as ornamentals. Rhodiola is sometimes included in the genus Sedum.