List of Rhododendron species

This List of Rhododendron species includes species of the genus Rhododendron, which is in the plant family Ericaceae. Depending on the source, there are anywhere from 800 to over 1,100 wild species.[1][2] The vast majority of Rhododendron species are native to the eastern Himalaya and southeast Tibet, along with the islands of Java, Sumatra, Borneo, New Guinea, and the Philippines. The rest are broadly spread throughout the northern hemisphere in relatively small isolated populations, including Japan, northwestern North America, the Appalachian, and the Caucasus Mountains.[3]

Rhododendron has eight traditionally accepted subgenera based on morphology, still the consensus taxonomy used by most authorities:[4] Azaleastrum; Candidastrum; Hymenanthes; Mumeazalea; Pentanthera; Rhododendron; Therorhodion; Tsutsusi.[5] Hymenanthes, with approximately 225 species, and subgenus Rhododendron, with approx. 400 species, comprise what gardeners typically describe as "Rhododendrons." Two subgenera are generally known to gardeners as "Azaleas", and include many fewer true species: Pentanthera, which comprises the deciduous azaleas, and Tsutsusi, which includes evergreen azaleas.[3]

Modern cladistic analysis, based on nuclear genetics, proposes changes in the classification of species within subgenera. These proposals are based on at least three different studies, with no changes proposed within subgenus Rhododendron and its sections. The major proposed changes are: to make section Choniastrum (originally in subgenus Azaleastrum) a separate Choniastrum subgenus; to combine sections Ponticum, Pentanthera, and the species Rhododendron canadense in subgenus Hymenanthes; subgenus Azaleastrum to include the former subgenera Tsutsusi, Mumeazalea, Candidastrum, and Menziesa, along with former sections Viscidula, Azaleastrum, Sciadorhodion, and the species Rhododendron vaseyi.[4]

As of 2024 the Plants of the World Online database lists 1091 accepted species and natural hybrids, all of which are listed here.[6]

 
Rhododendron arboreum
 
Rhododendron astrophorum
 
Rhododendron atlanticum
 
Rhododendron austrinum
 
Rhododendron bureavii
 
Rhododendron calendulaceum
 
Rhododendron canadense
 
Rhododendron capitatum
 
Rhododendron decorum
 
Rhododendron degronianum
 
Rhododendron ferrugineum
 
Rhododendron fuyuanense
 
Rhododendron groenlandicum
 
Rhododendron hippophaeoides
 
Rhododendron hyperythrum
 
Rhododendron impeditum
 
Rhododendron luteum
 
Rhododendron maximum
 
Rhododendron moulmainense
 
Rhododendron occidentale
 
Rhododendron periclymenoides
 
Rhododendron prunifolium
 
Rhododendron schlippenbachii
 
Rhododendron spinuliferum
 
Rhododendron tomentosum
 
Rhododendron vaseyi
 
Rhododendron wadanum
 
Rhododendron yedoense var. poukhanense

References

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  1. ^ Harold E. Greer (1996). Greer's guidebook to available rhododendrons: species & hybrids. Offshoot Publications. ISBN 978-0-910013-06-2. Retrieved 8 November 2012.
  2. ^ Roger V. Jean; D. Barabé (1998). Symmetry in Plants. World Scientific. pp. 6–. ISBN 978-981-02-2621-3. Retrieved 8 November 2012.
  3. ^ a b Irving, E.; R. Hebda (1993). "Concerning the Origin and Distribution of Rhododendrons". Journal of the American Rhododendron Society. American Rhododendron Society. Retrieved 4 November 2012.
  4. ^ a b Goetsch, Loretta; Eckert, Andrew J.; Hall, Benjamin D. (July–September 2005). "The molecular systematics of Rhododendron (Ericaceae): a phylogeny based upon RPB2 gene sequences". Systematic Botany. 30 (3): 616–626. doi:10.1600/0363644054782170. S2CID 51949019.
  5. ^ "Genus Rhododendron Taxonomic Tree". American Rhododendron Society. Retrieved 4 November 2012.
  6. ^ "Rhododendron L." Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 18 May 2024.
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