tamens totaling twice the number of petals; free or nearly free petals (not joined in a tube); a stout rhizome from whose axils the flowering stems rise; and a basal rosette of leaves. This genus contains the only species of Crassulaceae that have unisexual flowers.The Holarctic species Rhodiola rosea is used in herbal medicine. A number of species are grown as ornamentals, but growing them is difficult outside their native subarctic and alpine climates.The name combines the Greek rhodon, meanin