''Vireya'' rhododendron ''Rhododendron'' section ''Vireya'' (vireyas) is a tropical group of ''

Rhododendron ''Rhododendron'' (; from Ancient Greek ''rhódon'' "rose" and ''déndron'' "tree") is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are nati ...

'' species, numbering about 300 in all. Vireyas are native to southeastern Asia and range from

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Description

''Vireya'' are morphologically diverse, and characterised by

seeds A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm pl ...

with tailed appendages, the presence of

leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

idioblasts and capsule valves which twist upon opening. 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 In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...

''Rhododendron'', and includes about a third of all ''Rhododendron'' species. The exact classification has varied among various authors, some authors considering ''Vireya'' to be a separate

rather than as here, a section of the subgenus ''Rhododendron''. 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, although Brown etal., using phylogenetic analysis, found a lack of support for

monophyly In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic grou ...

of these subsections, and rather a series of

clades A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, t ...

based on geographical distribution: * R. subsect. ''Albovireya'' Sleumer, type ''

Rhododendron album ''Rhododendron album'' is a species of plant in the family Ericaceae. It is endemic to Java in Indonesia. It is a vulnerable species threatened by habitat loss. Description ''Rhododendron album'' is white, but can also appear lilac, depending ...

'' Blume * R. subsect. ''Euvireya'' Copel.f., type ''

Rhododendron javanicum ''Rhododendron javanicum'' is a rhododendron species native to Indonesia, Malaysia, and the Philippines. This evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing seas ...

'' (Blume) Benn * R. subsect. ''Malayovireya'' Sleumer, type '' Rhododendron malayanum'' Jack * R. subsect. ''Phaeovireya'' Sleumer, type ''

Rhododendron beyerinckianum ''Rhododendron beyerinckianum'' is a rhododendron species native to Indonesia and western Papua New Guinea, extending as far east as Mount Victoria, Papua New Guinea, Mount Victoria and Mount Dayman, where it grows at altitudes of 1400–4000 met ...

'' Koord. * R. subsect. ''Pseudovireya'' Clarke, type ''

Rhododendron vaccinioides ''Rhododendron'' (; from Ancient Greek ''rhódon'' "rose" and ''déndron'' "tree") is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are nati ...

'' Hook.f. * R. subsect. ''Siphonovireya'' Sleumer, type ''

Rhododendron habbemae ''Rhododendron'' (; from Ancient Greek ''rhódon'' "rose" and ''déndron'' "tree") is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are nati ...

'' Koord * R. subsect. ''Solenovireya'' Copel.f., type ''

Rhododendron jasminiflorum ''Rhododendron jasminiflorum'' is a rhododendron species native to Malacca and Mount Ophir in the Malay Peninsula. Growing to in height, it is an evergreen In botany, an evergreen is a plant which has foliage that remains green and funct ...

'' Hook. In Argent's (2006) treatment of Vireya as a subgenus, he included seven sections, with ''Euvireya'' consisting of five subsections, but this is not supported by phylogenetic analysis. These studies, for instance that of Hall (2006), suggested a very different approach. The Asian mainland species represented by ''Pseudovireya'' appear as a

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

to the other six subsections, while the Malesian species within ''Pseudovireya'' also formed an

outgroup Outgroup may refer to: * Outgroup (cladistics), an evolutionary-history concept * Outgroup (sociology), a social group {{disambig ...

, resulting in three major

. Thus Craven etal. 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. For a comparison of the Sleumer, Argent and Craven schemata, see Craven (2008), Table1. Thus the new subsection structure is: * R. subsect. ''Euvireya'' Copel.f., type ''Rhododendron javanicum'' (Blume) Benn * R. subsect. ''Malayovireya'' Sleumer, type '' Rhododendron malayanum'' Jack Characteristics:(Craven 2008) * ''Euvireya'' – Scales sessile or stalked, scattered or dense, not of two obviously different size classes, lobed to deeply incised (or sometimes entire) and the centre not dark-coloured. * ''Malayovireya'' – Scales sessile, dense, of two obviously different size classes, lobed and the centre dark-coloured.

Distribution

Vireya are found throughout the

Malesian Archipelago Malesia is a biogeographical region straddling the Equator and the boundaries of the Indomalayan and Australasian realms, and also a phytogeographical floristic region in the Paleotropical Kingdom. It has been given different definitions. Th ...

. Malesian species are found in all subsections, while species from other areas appear only in ''Euvvireya'', ''Malayovireya'' and ''Pseudovireya''. Found in that area an outstanding specimen ''Rhododendron loranthiflorum'' has been named after the New York guru Sri Chinmoy.John L. Rouse and Leslie A. Bursil
Rhododendron 'Sri Chinmoy'
JARS v53n1

References

Bibliography

* [http://www.rhododendron.fr/articles/2011%20Blumea%20classification%20of%20vireya.pdf L.A. Craven, F. Danet, J.F. Veldkamp, L.A. Goetsch, B.D. Hall. Vireya Rhododendrons: their monophyly and classification (''Ericaceae'', ''Rhododendron'' section ''Schistanthe''). Blumea 56, 2011: 153–158. 2011]
Goetsch, L.A., Craven, L.A. and Hall B.D. 2011. Major speciation accompanied the dispersal of Vireya Rhododendrons (Ericaceae, Rhododendron sect. Schistanthe) through the Malayan archipelago: Evidence from nuclear gene sequences. Taxon 60 (4): 1015–1028.

Peter Adams. Evolution, Adaptive Radiation and Vireya Rhododendrons - Part I. JARS FALL 2012 pp. 201-3

Peter Adams. Evolution, Adaptive Radiation and Vireya Rhododendrons - Part I. JARS SPRING 2013 pp. 74-76

Biodiversity of the Vireya group of ''Rhododendron'' L. (Ericaceae) collections in New Zealand and their potential contribution to international conservation. Fayaz A. PhD Thesis, Department of Plant Science, Massey University, New Zealand. 2012

External links

* {{Taxonbar, from=Q7321173

Vireya ''Vireya'' rhododendron ''Rhododendron'' section ''Vireya'' (vireyas) is a tropical group of ''Rhododendron'' species, numbering about 300 in all. Vireyas are native to southeastern Asia and range from Thailand to Australia. Description ''Vir ...

Plant sections