Gastrochilus tsii Q. Liu, D. P. Ye & X. H. Jin
Creators: name: Liu, Qiang
name: Wu, Xun-Feng
name: Zhou, Shi-Shun
name: Li, Jian-Wu
name: Jin, Xiao-Hua
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Asparagales
Orchidaceae
Gastrochilus
Gastrochilus tsii

description: Gastrochilus tsii Q. Liu, D.P. Ye & X.H. Jin, sp nov. (ằkfiffi±) (Figure 3–4)
Type:— CHINA. Yunnan Province: Zhenyuan County, Jiujia town, Qianjiazhai Village, Ailaoshan National Nature Reserve. Monsoon evergreen broad-leaved forest, 2300 m, epiphytic on tree trunks, 09 May 2016, Qiang Liu 354 (holotype: HITBC0056888!).
Morphologically, it is similar to G. distichus (Lindley 1858: 36) Kuntze (1891: 661) and G. pseudodistichus (King & Pantling 1896: 341) Schlechter (1913: 315) by having the pendulous and branched stem, but differs from G. distichus by having a sub-triangular epichile without conic calli at base—from G. pseudodistichus by having oblong-elliptic sepals, and sub-triangular epichile wider than hypochile.
Description:— Epiphytic herbs. Stem pendulous, 15–20 cm long, with 0.5–0.7 cm internodes, slender, often branched with tiny red-purple spots. Leaves alternate, distichous, ovate, 2.2–1.3 × 0.3–0.5 cm; apex acuminate and unequally 2-lobed with one awn. Inflorescences several, subumbellate, 3–4-flowered; peduncle 0.9–1.1 cm, slender, upper part enlarged, lower part with 2 sheaths; floral bracts ovate-lanceolate, 1.0– 1.2 mm; pedicel and ovary 0.3–0.4 cm. Flower yellow-green, sepals and petals with reddish brown spots. Dorsal sepal oblong-elliptic, concave, 3.2–3.8 × 2.0– 2.2 mm, apex acute. Lateral sepals similar to dorsal sepal, 3.2–4.2 × 2.0– 2.4 mm, apex acute; petals ovate, 3.0–3.2 × 1.5–1.6 mm, apex obtuse. Lip with an epichile and a saccate hypochile; epichile sub-triangular, 2.8–3.0 × 5.0– 5.5 mm, fleshy, adaxially glabrous, apex rounded; hypochile nearly cupular, mouth with lateral purple stripes, sac with reddish brown spots on the underside, 4.0– 4.5 mm tall, 4.0– 4.2 mm in diameter. Column stout with purple spots, ca. 1.2 mm; rostellum bilobed acuminate at the apex; pollinia 2, subglobose, ca. 0.3 mm in diameter; stipe elongate, ca. 0.7 mm; viscidium elliptic, thick and bilobed; anther cap galeate with a recurved–acuminate apex, 1.6 × 1.4mm. Capsules cylindrical, with 3 ridges, 2.0–2.2 × 0.7–0.8 cm.
Distribution and ecology:— The new species was found in Zhenyuan County, Dali Autonomous Prefecture, Yunnan Province, China, and Darjeeling state, India. Gastrochilus tsii grows on the tree trunks or rocks at altitudes from 2150 to 2300 m in Monsoon evergreen broad-leaved forest. Gastrochilus tsii was observed flowering from June to July in the wild.
Etymology:— The species epithet honors the late Prof. Tsi zhanhuo, (1936–2001), who devoted all his life to study Chinese orchids.
Taxonomic discussion:— After checking the specimens of Gastrochilus spp. kept at K, we found one specimen (voucher J.S. Gamble 8006) with drawing, collected by J.S. Gamble in 1879, from Darjeeling state, India (Figure 3G), identified as the G. distichus. It is easily distinguished from G. distichus by the illustrated flower characters. During our field expeditions in Yunnan province, we collected the fresh materials and the vegetative and floral characteristics are in congruity with the illustration of the Gamble specimen.
description: Published as part of Liu, Qiang, Wu, Xun-Feng, Zhou, Shi-Shun, Li, Jian-Wu & Jin, Xiao-Hua, 2023, New species and record of Gastrochilus (Orchidaceae, Aeridinae) from China and Laos, pp. 210-224 in Phytotaxa 585 (3) on pages 211-216, DOI: 10.11646/phytotaxa.585.3.3, http://zenodo.org/record/7690809