Blumea 56, 2011: 153–158 www.ingentaconnect.com/content/nhn/blumea RESEARCH ARTICLE doi:10.3767/000651911X590805 Vireya Rhododendrons: their monophyly and classification (Ericaceae, Rhododendron section Schistanthe) L.A. Craven1, F. Danet 2, J.F. Veldkamp3, L.A. Goetsch 4, B.D. Hall 4 Key words Abstract Further investigation into the evolutionary relationships of the vireya group of Rhododendron, utilising nuclear DNA sequence data, has demonstrated that this group of species is monophyletic, and a revised classification classification is presented. The name Vireya is predated at sectional level by several other valid names and the correct name Ericaceae for the section is now Schistanthe. Within Schistanthe, four subsections are recognised: Discovireya, Euvireya, key innovations Malayovireya and Pseudovireya. Revised identification keys are provided. Some morphological features of value morphology for classification and/or species delimitation are briefly discussed. Rhododendron Schistanthe Published on 20 July 2011 Vireya INTRODUCTION Argent, Pseudovireya (C.B.Clarke) Argent and Vireya, and presented a classification to this effect. Rhododendron L. is one of the larger genera of Ericaceae and Further sequencing of nuclear genes by B.D. Hall and L.A. contains between about 600 and 1 000 species, depending Goetsch for a comprehensive investigation into the relationships upon the species concept accepted by individual workers. One of subsect. Euvireya H.F.Copel. species has shown, however, of the largest of its several sections is Schistanthe, a group of that the vireyas are monophyletic (Goetsch et al. in press). The c. 300 species primarily found in south-eastern Asia and Malesia. phylogeny shown in Fig. 1 was obtained from analysis of data A very concise account of the classification of the genus, espe- from three nuclear genes (RPB2-i, RPC1 and RPB2-d) drawn cially in the context of molecular evidence, is given in Craven from a reduced number of species, but giving a similar pattern et al. (2008). As with that paper, the classification of the genus of relationships to that found by Goetsch et al. (in press). Two proposed by Goetsch et al. (2005) is followed here. Based species, R. perakense King & Gamble and R. santapaui Sastry, on analysis of sequence data from the nuclear gene RPB2-i, Kataki, P.A.Cox, P.B.Cox & Hutchison, are not placed with the Hall et al. (2006) found sect. Schistanthe Schltr. (previously species that they would be expected to group with on the basis Vireya (C.B.Clarke) H.F.Copel.) to be polyphyletic. The Male- of morphological evidence, i.e., Discovireya and Pseudovireya sian species of subsect. Pseudovireya (C.B.Clarke) Sleumer respectively. These two species, and several others that gave (sensu Sleumer 1966) formed a clade nested with several interesting results, are discussed by Goetsch et al. (in press). clades of sect. Pogonanthum G.Don and sect. Rhododendron Taking into account the clades recovered in the three nuclear species. The Continental Asian species of Pseudovireya were gene phylogeny shown in Fig. 1, together with morphological sister to a clade representative of all the other vireya species data, we conclude that four clades should be given taxonomic and these two clades were in a clade with two other clades of rank. As there are close phylogenetic relationships between sect. Rhododendron species. The Sumatran species R. van- the vireya group of species and sections Pogonanthum and derbiltianum Merr. was included by Sleumer (1966) in subsect. Rhododendron (Hall et al. 2006, Goetsch et al. in press), it Pseudovireya but this species is considered by Argent et al. to is appropriate that the vireya group be classified within subg. belong in sect. Rhododendron (Argent 2006: 37, as sect. Mad- Rhododendron, as placed by Craven et al. (2008), but ranked denia). DNA sequence evidence is equivocal with respect to at sectional level as the vireyas nest within the subgenus. R. vanderbiltianum which appears to be placed near the Subsectional status is warranted for the four vireya clades borderline between sections Rhododendron and Schistanthe recovered for which the following epithets are applicable: (Goetsch et al. in press). To obtain a more clear assessment Discovireya, Euvireya, Malayovireya and Pseudovireya. The of the relationships of R. vanderbiltianum, this species should morphological features that define these four subsections are be included in any future comprehensive phylogenetic studies given in the key following the classification below. Goetsch et of sect. Rhododendron. Drawing on the findings of Hall et al. al. (in press) found that there was no support for recognition at (2006), Craven et al. (2008) proposed that the vireya species any rank for the following taxa recognised by Sleumer (1966) be accommodated in three sections, Discovireya (Sleumer) and Argent (2006): Albovireya, Phaeovireya, Siphonovireya and Solenovireya. It must be noted, however, that only two rep- 1 Australian National Herbarium, CSIRO Plant Industry, GPO Box 1600, resentatives of Siphonovireya, R. herzogii Warb. and R. inun- Canberra, ACT 2601, Australia; corresponding author e-mail: [email protected]. datum Sleumer, were included in the DNA sampling by Goetsch 2 Mairie de Lyon, Espaces verts, Jardin botanique, Herbier, 69205 Lyon et al. (in press) and that it is possible that R. inundatum is not a cedex 01, France. biologically distinct species. Rhododendron inundatum recently 3 Netherlands Centre for Biodiversity Naturalis (section NHN), Leiden Uni- has been rediscovered near its type locality in a mosaic of in- versity, P.O. Box 9514, 2300 RA Leiden, The Netherlands. 4 Department of Biology, Box 1330, University of Washington, Seattle WA trogressive hybrids with R. herzogii, R. macgregoriae F.Muell. 98195-1330, USA. and R. × psammogenes Sleumer, the last-named being a © 2011 Nationaal Herbarium Nederland You are free to share - to copy, distribute and transmit the work, under the following conditions: Attribution: You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). Non-commercial: You may not use this work for commercial purposes. No derivative works: You may not alter, transform, or build upon this work. For any reuse or distribution, you must make clear to others the license terms of this work, which can be found at http://creativecommons.org/licenses/by-nc-nd/3.0/legalcode. Any of the above conditions can be waived if you get permission from the copyright holder. Nothing in this license impairs or restricts the author’s moral rights. 154 Blumea – Volume 56 / 2, 2011 100 R. konori 88 R. superbum R. carringtoniae 100 95 R. inconspicuum R. yelliotii 100 R. viriosum 86 R. rarum R. gracilentum 100 99 R. inundatum 89 R. herzogii R. zoelleri 100 R. alborugosum R. radians 100 100 R. rugosum R. maxwellii Euvireya 77 R. citrinum 100 R. aequabile R. sumatranum 100 R. album 100 99 R. buxifolium R. suaveolens 100 R. pudorinum 86 R. rhodopus R. zollingeri 100 R. renschianum 100 100 R. javanicum 100 R. rarilepidotum 100 R. brookeanum R. crassifolium R. apoanum 90 R. fallacinum 100 Malayovireya 93 R. malayanum R. himantodes 100 R. kawakamii 100 R. rushforthii 96 100 R. asperulum Pseudovireya 96 R. emarginatum R. vaccinioides R. perakense 86 R. gaultheriifolium * 100 100 R. ericoides 100 R. quadrasianum Discovireya 100 100 R. retusum R. adinophyllum R. minus 100 100 R. hypoleucum Outgroups R. tomentosum R. santapaui 100 R. micranthum * R. ferrugineum Outgroups R. stamineum R. camtschaticum Fig. 1 Inferred phylogeny of Rhododendron sect. Schistanthe based upon RPB2-i, RPB2-d and RPC1 sequence data. The numbers indicate bootstrap sup- port. See text for discussion of the placement of R. perakense and R. santapaui. putative hybrid between R. herzogii and R. macgregoriae, i.e., cannot be maintained for the vireya group as a single, inclusive R. × inundatum appears to have resulted from a backcrossing taxon. Craven et al. (2010) discussed the issue and accepted between R. herzogii and R. × psammogenes (Danet, unpubl. sect. Schistanthe as the correct name for the section. The data). The respective classifications of Sleumer (1966), Argent name change arises because the prior, valid publication of five (2006) and Craven et al. (2008) for the vireya group of Rhodo- sections by Schlechter (1917), all of which have nomenclatural dendron are contrasted in Table 1 with the classification pro- priority over sect. Vireya, was not taken into account by sub- posed in this paper. sequent authors who worked on the taxonomy of the vireya Significant changes to plant names are never well received group. For clarity, and simplicity in referencing, in the text of and it is regretted that, under the International Code of Botani- this paper Schistanthe is used in lieu of Vireya when referring cal Nomenclature (McNeill et al. 2006), the name sect. Vireya to pre-2010 literature. L.A. Craven et al.: Vireya Rhododendrons 155 Table 1 Comparison of the classifications by Sleumer (1966), Argent (2006) and Craven et al. (2008) of Rhododendron sect. Schistanthe with that of Craven et al. (this paper). Sleumer 1966 Argent 2006 Craven et al. 2008 Craven et al. (this paper) sect. Vireya subgenus Vireya sect. Vireya sect. Schistanthe subsect. Albovireya sect. Albovireya sect. Vireya subsect. Euvireya sect. Schistanthe subsect. Euvireya subsect. Euvireya sect. Vireya (as Euvireya) sect. Vireya subsect. Euvireya sect. Schistanthe subsect. Euvireya subsect.