Gastrochilus tsii Q. Liu, D.P. Ye & X.H. Jin

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, Phytotaxa 585 (3), pp. 210-224 : 211-216

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.

Figures

FIGURE 3. Gastrochilus tsii Q. Liu, D.P.Ye & X.H. Jin, sp nov. A. Habitat (Photographed by Zhou-Dong Han). B. Flowering and fruiting plant. C–F. Flower variability. G. Pressed specimen withdrawing from Darjeeling state, India (voucher J.S. Gamble 8066). H. Sepals and petals. I. Front and lateral view of lip. J. Pollinarium. K. Fruit. L. Leaf. M. Anther cap.

FIGURE 4. Gastrochilus tsii (A).A-1: Plant;A-2: Inflorescence and flowers. G. distichus (B). B-1: Plant; B-2: Inflorescence and flowers. G. pseudodistichus (C). C-1: Plant; C-2: Illustration (cited from Orchids of the Sikkim-Himalaya, Plate 305); C-3: Inflorescence and flowers. G. wenshenensis (D). D-1: Plant; D-2: Inflorescence and flowers.