Abstract: Based on a study of the type specimens of Sedum algidum Ledeb. var. tanguticum Maxim. (=Rkodiola algida (Ledeb.) Fisch.et Mey. var. tangutica (Maxim.) Fu), the var. tangutica should be a different species from Rhodiola algida. The two species may be summerized as below:Rhodiola algida:Flowers usually bisexual, sometimes with pistils obsolete; petals linear-lanceolate; stamens distinctly shorter than the petal. Distr. Altai region of China(?), USSR and Mongolia. Rhodiola tangutica:Plants dioecious, or occasionally with bisexual flowers(?):petals narrowly linear; stamens longer than the petals. Distr. Gansu,Qinghai and Sichuan (Dege Xian).