Gastrochilus xizangensis (Aeridinae, Vandeae, Orchidaceae), a new species from Xizang, China Author Chen, Wen-Shuai 0000-0002-9555-7105 Tibet Plateau Institute of Biology, Lhasa, Xizang 850001, China. & 443996502 @ qq. com; https: // orcid. org / 0000 - 0002 - 9555 - 7105 443996502@qq.com Author Lei, Ming 0000-0002-0135-1828 Tibet Plateau Institute of Biology, Lhasa, Xizang 850001, China. & 13322590085 @ 163. com; https: // orcid. org / 0000 - 0002 - 0135 - 1828 Author Ma, Chong-Bo 0000-0001-5869-8649 State Key Laboratory of Systematic and Evolutionary Botany and Herbarium, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China & 1130059815 @ qq. com; https: // orcid. org / 0000 - 0001 - 5869 - 8649 1130059815@qq.com Author Jin, Xiao-Hua 0000-0002-9987-5602 State Key Laboratory of Systematic and Evolutionary Botany and Herbarium, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China & xiaohuajin @ ibcas. ac. cn; https: // orcid. org / 0000 - 0002 - 9987 - 5602 xiaohuajin@ibcas.ac.cn Author Wang, Xi-Long 0000-0001-6965-3710 Tibet Plateau Institute of Biology, Lhasa, Xizang 850001, China. & wangxilong @ hotmail. com; https: // orcid. org / 0000 - 0001 - 6965 - 3710 wangxilong@hotmail.com text Phytotaxa 2022 2022-09-28 566 2 219 226 http://dx.doi.org/10.11646/phytotaxa.566.2.6 journal article 10.11646/phytotaxa.566.2.6 823fad5b-d2e2-4d1c-9271-d2c78cd12a4f 1179-3163 7119203 Gastrochilus xizangensis W.S.Chen, M.Lei & X.L.Wang , sp. nov . ( Fig.1 and 2 ) ( ƱAEfiffiż ) Type : CHINA . Xizang Autonomous Region , Cuona county , on branch of tree, elevation 2300 m , 2021, W.S. Chen , M. Lei , X.L.Wang , 2021001 ( holotype XZ!, isotype, XZ!) FIGURE 1. Morphology of Gastrochilus xizangensis A. Flower front view, back view, side view. B. Sepals, Petals and Epichile. C. From both sides to middle are lateral sepals, petals and dorsal speal. D. Lips and Hypochile front view, back view. E. Column. F. Anther cap. G. Pollinaria. H. Leaf apex with single awn. I. Leaf apex with three short awns. J. Plants. K. central cushion thickened, thickest at the edges as a ridge. FIGURE 2. A. Plant habitat. B–C. Flower. FIGURE 3. Bayesian phylogenetic tree of Gastrochilus based on combined ITS and plastid DNA markers ( matK 、 rps19-rpl22 、 trnL-F 、 psbM- trnD and psbA-trnH ), including 37 taxa of Gastrochilus , the posterior probability values given above the branches. Epiphytic herbs. Stems clustered, pendulous, rarely branched; 3–10 cm long, rooting. Leaves distichous, twisted at bases, leathery, narrowly elliptic, 10–12 × 3–5 mm , apex acute and with three short awns or not, smooth surface with purplish red speckles. Inflorescence lateral, 5–30 mm long, subumbellate, 1-8 flowered; peduncle 2–5 mm long, with a sterile bract, 1–3 mm long; floral bracts deltoid, 1 × 1.5–2.0 mm, apex acute; ovary and pedicel 6–7 mm long, with purple-red stripes; flowers not open widely, 4.5–5 mm long, 3.6–4.6 mm wide, yellow-green with sparse purple-red speckles, with sparse short hairs. Sepals and petals subequal, elliptic-oblong, slightly concave, 2.3–2.7 × ca. 1.0 mm, glabrous, abaxially slightly ridged, purple stripes on the ridges, margin entire or minutely erose. Lip composed by a saccate hypochile and a flat epichile of 3–3.5 mm long; hypochile conical, ca. 2 mm long, ca. 1.5 mm in diam., apex obtuse to round; epichile oblong or reniform, ca. 1.5 mm × 2.2 mm , consisting of a central cushion and a marginal part; central cushion thickened and green with purple-red spots, thickest at the edges as a ridge, densely with short hairs along the ridges; marginal part membranous and white, sparsely short hairs, apices broadly obtuse; column short and stout, ca. 1.3 mm long, 0.5 mm wide, footless; rostellum forked at apex; anther cap pentagonal, ca. 0.8 × 0.8 mm , apex pointed and upturned; pollinarium ca. 1 mm long; pollinia 2, yellow, waxy, ellipsoid, on a slender stipe; stipe slender, ca. 0.7 mm long; viscidium elliptic. Distribution and habitat: —Known so far only from Cuona County, Southeast of Xizang Autonomous Region, as epiphytic plants on tree barks in a broad-leaved forest at elevation of 2300 m . Phenology: —Flowering in April. Etymology: —In reference to the type-locality of the new species. Conservation status: —There are two populations of the new species, which consists of no more than 50 individuals (clumps). According to the IUCN categories (2022), G. xizangensis should be treated as Data Deficient.