Rhododendron sect. Vireya

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Rhododendron sect. Vireya
Rhododendron javanicum brookeanum (14012162344).jpg
Rhododendron javanicum
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Ericales
Family: Ericaceae
Genus: Rhododendron
Subgenus: Rhododendron subg. Rhododendron
Section: Rhododendron sect. Vireya
(Blume) H.F.Copel.
Type species
Rhododendron javanicum
(Blume) Benn.
Subsections

See text

Synonyms

Schistanthe Schltr.

Vireya rhododendron Vireya.jpg
Vireya rhododendron

Rhododendron section Vireya (vireyas) is a tropical group of Rhododendron species, numbering about 300 in all. [1] The group may also be treated as Rhododendron subgenus Vireya. [2] Vireyas are native to southeastern Asia and range from Thailand to Australia. [3]

Contents

Description

Rhododendron 'Kamrau Bay', a hybrid whose background includes R. zoelleri and R. laetum Vireya Kamrau Bay.jpg
Rhododendron 'Kamrau Bay', a hybrid whose background includes R. zoelleri and R. laetum

Vireya are morphologically diverse, and characterised by seeds with tailed appendages, the presence of leaf idioblasts and capsule valves which twist upon opening. [5]

The formal description (Craven 2008) is: Scales sessile or sometimes stalked, lobed to deeply incised or sometimes entire; corolla campanulate, trumpet-like, salver-shaped, tubular or funnel-shaped; stamens (5–)10(–16), exserted to included, staminal filaments glabrous or hairy from the base; capsule valves twisting after dehiscence; seeds with a distinct tail at each end.

Taxonomy

Vireya is the largest of the three sections constituting subgenus Rhododendron, and includes about a third of all Rhododendron species. [6] The exact classification has varied among various authors, some authors considering Vireya to be a separate subgenus [7] rather than as here, a section of the subgenus Rhododendron. [1] [2] It has been suggested that taxonomic nomenclatural correctness requires changing the name of the Vireya rhododendrons to Schistanthe. Thus the term 'Vireya' has been used to refer to Section Vireya (Sleumer), Subgenus Vireya, Section Schistanthe, or the majority of the Malesian tropical rhododendrons. (Fayaz). Goetsch (2011) gives the number of species as 320, and the total taxa including subspecies, forms and varieties as 380.

Subdivision

The section has traditionally been considered to consist of seven subsections based on morphology, [8] although Brown et al., using phylogenetic analysis, found a lack of support for monophyly of these subsections, and rather a series of clades based on geographical distribution: [5]

In Argent's (2006) treatment of Vireya as a subgenus, he included seven sections, with Euvireya consisting of five subsections, [7] but this is not supported by phylogenetic analysis. [1] These studies, for instance that of Hall (2006), [9] suggested a very different approach. The Asian mainland species represented by Pseudovireya appear as a sister group to the other six subsections, while the Malesian species within Pseudovireya also formed an outgroup, resulting in three major clades. Thus Craven et al. proposed there be only two subsections of Vireya, corresponding to the core species, Euvireya and the much smaller Malayovireya , while the other two groups formed out of Pseudovireya be raised to section rank, keeping the original name Pseudovireya for the mainland species, and using Argent's name, Discovireya for the Malesian species. [1] For a comparison of the Sleumer, Argent and Craven schemata, see Craven (2008), Table 1.

Thus the new subsection structure is:

Characteristics:(Craven 2008)

As of December 2023, World Flora Online treated the group as R. subg.Vireya, divided into seven sections: [2]

Distribution

Vireya are found throughout the Malesian Archipelago – Peninsular Malaysia, Sumatra, Borneo, Java, the Philippines, Sulawesi, the Lesser Sunda Islands, and Maluku – and in Papuasia, which includes New Guinea, the Bismarck Archipelago, and the Solomon Islands. Some Vireya species also occur in Australia, China, India, Nepal, Taiwan, and Vietnam. Only a few non-Vireya species occur in Malesia, in the Malay Peninsula, Sumatra, and the Philippines. [5] Malesian species are found in all subsections, while species from other areas appear only in Euvvireya, Malayovireya and Pseudovireya. [1]

New Guinea has the most Vireya species of any island, with 167 species. Borneo has 46 species, the second most of any island. [10]

Related Research Articles

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<i>Gaultheria</i> Genus of flowering plants

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<i>Rhododendron <span style="font-style:normal;">subsect.</span> Ledum</i> Subsection of genus Rhododendron

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<i>Rhododendron <span style="font-style:normal;">sect.</span> Rhodora</i> Section of flowering plants

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<i>Rhododendron <span style="font-style:normal;">subg.</span> Rhododendron</i> Subgenus of flowering plants

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<i>Rhododendron spinuliferum</i> Species of plant

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<i>Rhododendron lochiae</i> Species of plant native to Queensland, Australia

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<i>Rhododendron <span style="font-style:normal;">sect.</span> Tsutsusi</i> Group of shrubs

Rhododendron section Tsutsusi was a subgenus of the genus Rhododendron, commonly referred to as the evergreen azaleas. In 2005 it was reduced to a section of subgenus Azaleastrum. Containing 80 - 117 species, it includes both deciduous and evergreen types and is distributed in Japan, China and northeastern Asia. They are of high cultural importance to the Japanese. Among the species in this genus lie the largest flowering azaleas.

<i>Rhododendron beyerinckianum</i> Species of plant

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<i>Rhododendron <span style="font-style:normal;">subg.</span> Azaleastrum</i> Subgenus of flowering plants

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<i>Rhododendron <span style="font-style:normal;">subsect.</span> Brachycalyx</i> Group of shrubs

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<i>Rhododendron <span style="font-style:normal;">subsect.</span> Tsutsusi</i> Group of shrubs

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<i>Rhododendron javanicum</i> Species of plant

Rhododendron javanicum is a rhododendron species native to Indonesia, Malaysia, and the Philippines. This evergreen shrub grows to 5 m (16 ft) with bright orange flowers in spring. Plants may be terrestrial or epiphytic. Some forms from the Philippines may have red or bicoloured flowers, but are less often seen in cultivation.

References

  1. 1 2 3 4 5 Craven, L.A.; Goetsch, L.A.; Hall, B.D.; Brown, G.K. (2008). "Classification of the Vireya group of Rhododendron (Ericaceae)". Blumea - Biodiversity, Evolution and Biogeography of Plants. 53 (2): 435. doi:10.3767/000651908X608070.
  2. 1 2 3 WFO (December 2023). "Rhododendron subg. Vireya L." World Flora Online. Retrieved 2024-02-22.
  3. Chamberlain, DF; Hyam R; Argent G; Fairweather G; Walter KS (1996). The genus Rhododendron: its classification and synonymy. Royal Botanic gardens Edinburgh. ISBN   1-872291-66-X. Archived from the original on July 14, 2014. Retrieved July 3, 2014.
  4. "Vireya Hybrid Gallery: K".
  5. 1 2 3 Gillian K. Brown, Lyn A. Craven, Frank Udovicic and Pauline Y. Ladiges. Phylogenetic relationships of Rhododendron section Vireya (Ericaceae) inferred from the ITS nrDNA region. Australian Systematic Botany 19, 329–342. August 2006. 10.1071/SB05019
  6. Goetsch, Loretta A.; 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.
  7. 1 2 Argent, G. Rhododendrons of subgenus Vireya. 2006. Royal Horticultural Society. ISBN   1-902896-61-0
  8. Sleumer, Hermann Otto (1966) Ericaceae 1. Rhododendron: An account of rhododendron in Malesia, in ‘Flora Malesiana’. (Ed. CGGJ van Steenis) pp. 469–656. (Wolters-Noordhoff Publishing: Groningen, The Netherlands
  9. Hall, B.D., L.A. Craven & L.A. Goetsch. 2006. The taxonomy of subsection Pseudovireya – two distinctly different taxa within subsection Pseudovireya and their relation to the rooting of section Vireya within subgenus Rhododendron. Rhododendron Sp. 1: 72, 91–97
  10. G. Argent (1985) Vireya Rhododendrons in Borneo. Notes from the Royal Botanic Garden, Edinburgh 43 53–61

Bibliography