Rhodiola

Rhodiola is a genus of perennial plants in the family Crassulaceae[1] that resemble Sedum and other members of the family. Like sedums, Rhodiola species are often called stonecrops. Some authors merge Rhodiola into Sedum.[2][3]

This article is about the plant genus. For the particular species widely used in herbal medicine (as "golden root", "roseroot", etc.), see Rhodiola rosea.

Rhodiola
Rhodiola heterodonta
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Saxifragales
Family: Crassulaceae
Subfamily: Sempervivoideae
Tribe: Umbiliceae
Genus: Rhodiola
L.
Species

c. 90

Rhodiola species grow in high-altitude and other cold regions of the Northern Hemisphere.[4] Den virtuella floran gives the number of species as 36,[5] the Angiosperm Phylogeny Website gives it as 90,[1] and the Flora of China gives it as about 90, with 55 in China and 16 endemic there.[4] Flora of North America lists only three species in the United States and Canada.[6]

Description

Among the distinguishing characters of the genus are two series of stamens 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.[4][7]

Phytochemistry

Rhodionin is a herbacetin rhamnoside found in Rhodiola species.[8]

  • Rhodiolin [86831-53-0]
  • Rhodiolgin [94696-39-6]

Taxonomy

Although Linnaeus distinguished Rhodiola from Sedum on the basis of being dioecious,[9] it was later submerged in the latter genus until the twentieth century, when it was restored, on the basis of well developed rhizomes and annual flowering stems, arising from axils of the scaly radical leaves. This separation was subsequently confirmed by molecular phylogenetic studies. [10]

Rhodiola is placed within family Crassulaceae, in subfamily Sempervivoideae, tribe Umbiliceae. There it is a sister group to Pseudosedum,[11] though some authors have suggested that the latter genus be submersed within Rhodiola.[10]

Subdivision

Traditionally Rhodiola was divided into subgenera, sections and series, based on plant characteristics. Four subgenera were recognised; Rhodiola, Primuloides, Crassipedes and Clementsia. However molecular studies have failed to demonstrate monophyly of these subtaxa.[10]

Species include:

Etymology

The name combines the Greek rhodon, meaning rose and referring to the rose-like smell of the roots, with the Latin diminutive suffix -iola.[12]

Ecology

Dioecy, having separate male and female flowers, has evolved at least three times in the genus, and reversals to a hermaphrodite condition have also occurred, which is a rare occurrence in flowering plants. It has been suggested that dioecy in the genus may correlate with abiotic pollination in the cold environment.[13]

Uses

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.[14]

References
  1. Stevens 2019.
  2. Ivey, Robert DeWitt (2003), Flowering Plants of New Mexico (Fourth ed.), RD & V Ivey, p. 246, ISBN 0-9612170-3-0
  3. "Sedum integrifolium ssp. leedyi", National Collection of Imperiled Plants, Center for Plant Conservation, 2008-01-29, retrieved 2009-07-26
  4. Fu, Kunjun; Ohba, Hideaki; Gilbert, Michael G., "Rhodiola Linnaeus, Sp. Pl. 2: 1035. 1753", Flora of China, 8, p. 251, retrieved 2009-07-26
  5. "Rhodiola L.: Rosenrötter", Den virtuella floran (in Swedish), Naturhistoriska riksmuseet, 2000-04-18 [1997], retrieved 2009-07-26
  6. Reid V. Moran (2009), "Rhodiola Linnaeus, Sp. Pl. 2: 1035. 1753; Gen. Pl. ed. 5, 457. 1754", Flora of North America Online, 8
  7. Kunjun Fu, Hideaki Ohba, and Michael G. Gilbert, "Crassulaceae Candolle", Flora of China, 8CS1 maint: uses authors parameter (link)
  8. Li & Zhang 2008.
  9. Linnaeus 1753.
  10. Mayuzumi & Ohba 2004.
  11. Thiede & Eggli 2007.
  12. Eggli & Newton 2004, p. 203.
  13. Zhang et al 2014.
  14. Stephenson, Ray (1994), Sedum: Cultivated Stonecrops, Timber Press, pp. 289–290, ISBN 0-88192-238-2, retrieved 2009-07-26

Bibliography
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