Coelogyne magnifica (Orchidaceae), a new species from Putao, Kachin State, Myanmar, is described and illustrated. It belongs to Coelogyne section Ocellatae Pfitzer & Kraenzl. and it is morphologically similar to Coelogyne corymbosa and C. taronensis, but can be distinguished from these species by its larger flowers, lanceolate sepals and petals, a narrowly ovate lip, which has two bright yellow patches surrounded by shiny brownish red and two fimbriate or erose-lacerate lateral keels on the lip. The major differences between these species are outlined and discussed.

Kachin state, section Ocellatae, key, plant taxonomy, IUCN, Hponkan Razi

The genus Coelogyne Lindl. (Lindley 1821), which consists of approximately 200 species, is distributed from South India, through tropical Asia and the Malay Archipelago into the Pacific as far east as Fiji, with the main centres being in Borneo, Sumatra and the Himalayas (Gravendeel 2000, Clayton 2002, Gravendeel et al. 2001, 2005, Chen and Clayton 2009, George and George 2011). It belongs to the subfamily Epidendroideae, tribe Coelogyneae, subtribe Coelogyninae (Gravendeel et al. 2005). As currently circumscribed based on molecular phylogenetic evidence, Coelogyne is polyphyletic and composed of species belonging to two unrelated groups. It would thus be questionable whether to adopt a Coelogynes.s. generic delimitation or a Coelogynes.l. generic circumscription (Gravendeel 2000, Gravendeel et al. 2001). Although revisions of several sections of Coelogyne have been published in the last decade (Gravendeel and de Vogel 1999, Pelser et al. 2000), a comprehensive infrageneric delimitation combined with descriptions of morphological and molecular characters based on more extensive sampling within Coelogyne is needed (Gravendeel et al. 2000, Sierra et al. 2000).

Historically, the study of Coelogyne in Myanmar dates back to Hooker (1890), who reported three Coelogyne species and added one new species Coelogyne longibractata Hook. f.. Currently, 43 species of Coelogyne have been recorded in Myanmar (Kress et al. 2003), although in a recently published field guide to the orchids of Myanmar, only 33 Coelogyne species are described (Kurzweil and Lwin 2014). The most recently identified new species of Coelogyne was Coelogyne putaoensis X.H. Jin, L.A. Ye & Schuit. is from north Myanmar (Aung et al. 2017). Since the publication of Kress’s checklist (Kress et al. 2003), more than 10 new species and 40 new records of Orchidaceae species have been added to the flora of Myanmar from 2001 to the present (Yang and Tan, unpublished data).

During recent China–Myanmar joint field expeditions to survey plant diversity in north Myanmar in May 2016 and 2017, specimens of Coelogyne were found in Putao, Kachin State. On the basis of a detailed examination of the morphological and anatomical characters of this material and of presumed closely similar species (Clayton 2002, Kress et al. 2003, Chen and Clayton 2009, George and George 2011, Subedi 2011, Yonzone 2012a, 2012b, Li and Dao 2014, Gogoi et al. 2015, Aung et al. 2017), the conclusion was made that the specimens collected in Myanmar belong to a species new to science, which is herein described and illustrated.

Measurements and morphological character assessments of the putative new Coelogyne species were performed and described using specimens and fresh material observed in the field. These data were compared with those for the morphologically similar species C. corymbosa Lindl. and C. taronensis Hand.-Mazz. based on the descriptions of dried herbarium specimens deposited at Xishuangbanna Tropical Botanical Garden herbarium (HITBC), field notes (for C. corymbosa which has also been collected from north Myanmar) and literature descriptions (Chen and Clayton 2009, Subedi 2011, Li and Dao 2014). Protologues and images of type specimens were obtained from Tropicos (http://www.tropicos.org), JSTOR Global Plants (http://plants.jstor.org) and the International Plant Names Index (http://www. ipni.org).

According to monographic works (Clayton 2002, Chen and Clayton 2009, George and George 2011, Subedi 2011), Coelogyne magnifica obviously belongs to sect. Ocellatae Pfitzer & Kraenzl. (Pfitzer and Kraenzlin 1907), which is characterised by the white or pale coloured flowers with colourful eyelike blotches on the lateral lobes and lip. This section shows its centre of diversity in the Himalayas (Subedi 2011). Coelogyne magnifica is similar to both C. corymbosa and C. taronensis in terms of vegetative morphology and shape of the flowers, but differs mainly with respect to the characters of patches and keels on the lip. Morphologically, the new species is most similar to C. corymbosa, with both having white flowers, ovoid pseudobulbs sometimes and obovate-oblong leaf blades. These two species are also distributed in the same locality in north Myanmar. Nevertheless, the new species differs from C. corymbosa in having slightly smaller pseudobulbs, shorter leaf blades, a greater number of larger flowers, two bright yellow patches surrounded by shiny brownish red (vs. four yellow eye-like blotches) and two fimbriate or erose-lacerate lateral keels on the lip (vs. two–three keels, with margins wavy or crenulate) (Table 1). The tepals (perianth lobes, including sepals, petals and lip) of C. magnifica are lanceolate, 4.0–4.9 cm long (vs. mostly elliptic to ovate, 2.4–3.7 cm long in C. corymbosa). Although the other morphologically similar species, C. taronensis, is similar to the new species with respect to ovoid pseudobulbs and in flower size, the new species differs from C. taronensis with regards to its white flowers (vs. creamy yellow in C. taronensis) (Figure 2), smaller leaf blades (Table 1), patches (two bright yellow patches vs. four dark red patches) and keels (two keels vs. three keels) on the lip. The major differences between the species are outlined in Table 1.

The authors are grateful to Xiaohua Jin and another two anonymous reviewers and editors for their positive and constructive comments and suggestions for this manuscript. We are also grateful to the Forest Research Institute of Myanmar for permission to conduct this study in northern Myanmar and for their support and collaboration. We are grateful to Myint Zaw and Myint Kyaw for their exhaustive help in the field work. We thank Yunxi Zhu for the illustration and Xiangle Zeng for providing us a photo. This work was financially supported by a project of the Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences (Grant No.Y4ZK111B01).