
Belongs within: Crassulaceae.
Rhodiola is a genus of perennial, fleshy herbs found in high altitudes and frigid regions of the Northern Hemisphere.
Characters (from Flora of China): Herbs perennial, with some dimorphism. Rhizome a fleshy caudex, thick or slender, apex usually at or slightly above ground level. Caudex leaves present, usually reduced and scalelike, but sometimes with well-developed leaf blade. Flowering stems one to many, arising from axils of caudex leaves, annual, simple, leafy; dried remains of old stems sometimes persisting. Stem leaves usually alternate, occasionally verticillate or opposite, simple, fleshy. Inflorescences terminal, a simply or compoundly corymbiform or dichotomous cyme, less often 1-flowered, rarely a helicoid cyme or with additional axillary inflorescences arising from distal leaf axils, usually bracteate and pedunculate. Flowers usually bisexual, sometimes unisexual. Calyx (3 or)4- or 5(or 6)-parted. Petals ± free, as many as sepals. Stamens in 2 series, usually 2 × as many as petals; antepetalous stamens adnate to basal part of petals; anthers mostly purple before anthesis, later turning yellow, basifixed or less often dorsifixed, 2-loculed. Nectar scales linear, oblong, suborbicular, or quadrangular. Ovary superior; carpels as many as petals. Follicles few to many seeded.
<==Rhodiola |--R. amabilisO88 |--R. bupleuroidesO88 | |--R. b. var. bupleuroidesKO88 | `--R. b. var. parvaKO88 |--R. callianthaO88 |--R. coccineaO88 |--R. crenulataO88 |--R. cretiniiO88 |--R. discolorO88 |--R. fastigiataO88 |--R. heterodontaO88 |--R. himalensisO88 | |--R. h. ssp. himalensisO88 | `--R. h. ssp. bouvieriO88 |--R. humilisO88 |--R. imbricataO88 |--R. lobulataO88 |--R. nepalicaO88 |--R. pamiroalaicaO88 |--R. prainiiO88 |--R. purpureoviridisO88 | |--R. p. ssp. purpureoviridisO88 | `--R. p. ssp. phariensisO88 |--R. smithiiO88 `--R. wallichianaO88
*Type species of generic name indicated
References
[KO88] Kikuchi, T., & H. Ohba. 1988. Preliminary study of alpine vegetation of the Himalayas, with special reference to the small-scale distribution patterns of plant communities. In: Ohba, H., & S. B. Malla (eds) The Himalayan Plants vol. 1. The University Museum, University of Tokyo, Bulletin 31: 47–70.
[O88] Ohba, H. 1988. The alpine flora of the Nepal Himalayas: an introductory note. In: Ohba, H., & S. B. Malla (eds) The Himalayan Plants vol. 1. The University Museum, University of Tokyo, Bulletin 31: 19-46.