RHODIOLA, in botany, a genus of the dioecia conoandria class. The calix of the male consists of four segments, and the corolla of four petals; the calix of the female has four segments; it has no corolla, but four nectaria, and four pistils; and it has four capsules, containing many seeds. There is but one species, viz. the rosea, or rose-wort, a native of Britain.