Coelogyne putaoensis (Orchidaceae), a new species from Myanmar

Abstract Coelogyne putaoensis, a new species of section Ocellatae from Putao, Kachin State, Myanmar, is described and illustrated. It is morphologically similar to C. taronensis and C. weixiensis, presumably its nearest relatives. An identification key and colour photographs are provided. A preliminary risk-of-extinction assessment according to the IUCN Red List categories and criteria is given for the new species.


Introduction
Coelogyne Lindl. (Lindley 1821) (Orchidaceae, Epidendroideae, Arethuseae) is a genus of about 200 species, distributed from South and Southeast Asia into the Pacific as far east as Fiji and Samoa (Clayton 2002, Chen et al. 2009, George and George 2011, Gravendeel 2005. Around 45 species of Coelogyne have been recorded from Myanmar (Kress et al. 2003;Kurzweil and Lwin 2014). During fieldwork in Putao, Kachin State, Northern Myanmar, in June 2016, the first authors discovered a new species of Coelogyne, which is described below. The new species belongs to Coelogyne section Ocellatae Pfitzer & Kraenzl. (Pfitzer and Kraenzl. 1907).

Material and methods
All measurements of the three species here discussed, i.e., Coelogyne putaoensis, C. taronensis Handel-Mazzetti and C. weixiensis X.H. Jin, were taken from dried herbarium specimens and field notes. In the description, length and width are represented as length × width. About twenty living plants and three dried specimens of the new species and 10 specimens each of C. taronensis and C. weixiensis, including types or photos of types of all taxa, were examined.

Taxonomic treatment
Coelogyne putaoensis X.H. Jin, L.A. Ye & Schuit., sp. nov. urn:lsid:ipni.org:names:77163812-1 Figures 1-3 Diagnosis. Coelogyne putaoensis is similar to C. taronensis and C. weixiensis, but can be distinguished by its solid yellowish brown sepals and petals, a brown lip with bright yellow markings, three keels extending from the base of the lip onto the mid-lobe, and lateral keels adorned with papillae.
Etymology. The new species is named after Putao, the northernmost town of Myanmar near which it was discovered in a vast area of unspoiled mountain forest. Distribution and habitat. Coelogyne putaoensis is a predominantly epiphytic species that grows on moss-covered branches and tree trunks, sometimes also on rocks, in humid, broad-leaved, evergreen, montane forest, from 2500 to 3100 m elevation. At present, C. putaoensis is only known from the type locality.

Conservation status. Least Concern (LC).
Coelogyne putaoensis was collected in the Hponkanrazi Wildlife Sanctuary, Putao, Northern Myanmar. Until now, only one population, consisting of ca. 200 individuals, has been discovered in the reserve (1044 square miles), which is a legally protected area under the management of the Myanmar Forest Department. As no threat currently affects the quality of its habitat and the number of mature individuals, the species is here assigned a preliminary status of Least Concern (LC) according to the guidelines for using the IUCN Red List Categories and Criteria (IUCN Standards and Petitions Subcommittee 2017).

Discussion
Coelogyne taronensis, C. weixiensis and C. putaoensis are similar, both in vegetative morphology and in the size and shape of the flowers, and all come from the same general region, northern Myanmar and adjacent parts of China. There can be little doubt that they are closely related. They are readily distinguished on the basis of their colour differences, as indicated in the key and photos. Coelogyne weixiensis ( Figure 4) and C. taronensis ( Figure 5) are especially similar morphologically. They are listed as synonyms by George and George (2011). At present, too little is known about the variability of C. taronensis to make any assessment with confidence. Both taxa appear to be rare and local (C. weixiensis: China, Yunnan, Bilou Snow Mountains near Weixi; C. taronensis: China, Yunnan, Taron (=Dulong) Valley). Coelogyne putaoensis differs from the two others not only in having almost solid brown flowers, but also in the papillose margins of the keels on the lip, and in the median keel extending onto the mid-lobe. Altitudinal range and habitat are comparable for the three species: C. putaoensis was collected at 2500-3100 m, C. taronensis at 2400-3500 m, and C. weixiensis at 2600-3000 m elevation (Jin 2005). All three occur as epiphytes in montane forest. At least two of the three species (C. taronensis and C. weixiensis) are of high conservation interest, and habitat protection seems urgently needed for these. As far as we can ascertain, only C. weixiensis is currently in cultivation, having recently received a Botanical Certificate of the Royal Horticultural Society in the UK (as C. taronensis).