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]
Buddleja is a genus comprising over 140 species of flowering plants endemic to Asia, Africa, and the Americas. The generic name bestowed by Linnaeus posthumously honoured the Reverend Adam Buddle (1662–1715), an English botanist and rector, at the suggestion of Dr. William Houstoun. Houstoun sent the first plants to become known to science as buddleja to England from the Caribbean about 15 years after Buddle's death. Buddleja species, especially Buddleja davidii and interspecific hybrids, are commonly known as butterfly bushes and are frequently cultivated as garden shrubs. Buddleja davidii has become an invasive species in both Europe and North America.
Cotoneaster is a genus of flowering plants in the rose family, Rosaceae, native to the Palaearctic region, with a strong concentration of diversity in the genus in the mountains of southwestern China and the Himalayas. They are related to hawthorns (Crataegus), firethorns (Pyracantha), photinias (Photinia), and rowans (Sorbus).
Anaphalis is a genus of herbaceous and woody flowering plants within the family Asteraceae, whose members are commonly known by the name pearl or pearly everlasting. There are around 110 species with the vast majority being native to central and southern Asia. There is one species native to North America that is fairly well known and popular in cultivation, namely the western pearly everlasting.
Cremanthodium is a large genus of flowering plants in the daisy family.
Briggsia was a genus in the family Gesneriacae that consisted of 22 species of herbaceous perennials, native to the Himalayas, China and Vietnam. The genus is no longer recognized, with all of its member species having been relocated to other genera, including Glabrella, Loxostigma, and Oreocharis.
Rhododendron alutaceum is a species of flowering plant in the family Ericaceae. It is native to Tibet and southwestern China, where it grows at altitudes of 3,200–4,300 m (10,500–14,100 ft). This evergreen shrub that grows to 1.5–4 m (4.9–13.1 ft) in height, with thick, leathery leaves that are oblong and broadly lanceolate to lanceolate or narrowly oblong, 5–14 by 1.5–3.5 cm in size. The flowers are white to pink, with crimson spots and purplish-red basal blotch.
Elsholtzia is a plant genus in the Lamiaceae. It is widespread across much of temperate and tropical Asia from Siberia south to China, Northeastern India, Indonesia, etc. The genus was named in honour of the Prussian naturalist Johann Sigismund Elsholtz.
Rhododendron argyrophyllum (银叶杜鹃) is a species of flowering plant in the heath family Ericaceae. It is native to forested slopes at 1,600–2,300 m (5,200–7,500 ft) in E and NW Guizhou, S and W Sichuan, and NE Yunnan in China.
Rhododendron rigidum (基毛杜鹃) is a rhododendron species native to Sichuan and Yunnan, China, where it grows at altitudes of 2,000–3,400 m (6,600–11,200 ft). Growing to 1–2 m (3.3–6.6 ft) in height, it is an evergreen shrub with leaves that are elliptic, oblong elliptic, oblong-lanceolate or oblanceolate, 2.5–6.8 by 1–3.2 cm in size. The flowers are white to reddish purple.
Rhododendron selense (多变杜鹃) is a rhododendron species native to southwestern Sichuan, eastern Xizang, and western Yunnan in China, where it grows at altitudes of 2,700–4,000 m (8,900–13,100 ft). It is an evergreen shrub that grows to 1–2 m (3.3–6.6 ft) in height, with leaves that are oblong-elliptic or obovate to elliptic, 4–8 by 2–4 cm in size. The flowers are pink.
Rhododendron uvariifolium (紫玉盘杜鹃) is a rhododendron species native to southwestern Sichuan, southeastern Xizang, and northwestern Yunnan in China, where it grows at altitudes of 2,100–4,000 m (6,900–13,100 ft). It is an evergreen shrub or tree growing to 2–10 m (6.6–32.8 ft) in height, with leathery leaves that are oblanceolate to oblong-oblanceolate or obovate, 11–24 by 3.5–6.5 cm in size. Flowers are white, pink, or rose, with crimson basal blotch and purple spots.
Rhododendron vernicosum (亮叶杜鹃) is a rhododendron species native to western Sichuan, southeastern Xizang, and western Yunnan, China, where it grows at altitudes of 2,600–4,300 m (8,500–14,100 ft). It is an evergreen shrub typically growing to 1–5 m (3.3–16.4 ft) in height, with leathery leaves that are oblong-ovate to oblong-elliptic, and 5–12.5 × 2.3–4.8 cm in size. The flowers are somewhat fragrant, and pale pink or white.
Rhododendron calophytum, the beautiful-face rhododendron, is a species of flowering plant in the heath family Ericaceae that is native to the forests of central and eastern China, where it lives at altitudes of 1,400–4,000 m (4,600–13,100 ft). Growing to 12 m (39 ft) tall and 8 m (26 ft) broad, it is a substantial evergreen shrub. The leathery leaves are narrow and up to 30 cm (12 in) long. In early Spring trusses of bell-shaped, white or pale pink flowers, spotted with maroon inside, are produced.