Gastrochilus labrosus Q. Liu & X.H. Jin, 2023

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 : 218-220

Gastrochilus labrosus Q. Liu & X.H. Jin , sp. nov. (ṾḆfiffi±) ( Figure 6 )

Type: — CHINA. Yunnan Province: Wenshan Zhuang-Miao Autonomous Prefecture, Malipo County, Xiajinchang Village , limestone forest, 1970 m, 16 July 2015, Qiang Liu 373 (holotype: HITBC0056903!) .

Morphologically, it is similar to Gastrochilus guangtungensis Z.H. Tsi (1996: 139) and G. minutiflorus Averyanov (1997: 145) by having the stout and pendent stem, but differs by having narrow epichile without central cushion and white membranous marginal wings.

Description:— Epiphytic plant with stout and pendent stem up to 12 cm long. Leaves lanceolate, falcate, densely purpleviolet spotted, 5.0–5.5 × 1.0– 1.2 cm, sessile with articulation at the base; apex acuminate with 1 awn. Inflorescence short, subumbellate, usually with 4-flowered, bracts small triangular. Flower yellow with white hypochile. Sepals and petals yellow with purplish spots, epichile of lip yellow with densely purplish spots, hypochile of lip white and margin with purple stripes. Dorsal and lateral sepals similar, obovate, 4.0–4.5 × 2.5–3.0 mm, apex obtuse. Petals narrow, ovate- lanceolate, 4.5–5.0 × 2.0– 2.2 mm, apex obtuse. Lip with an epichile and a saccate hypochile; epichile nearly suborbicular, 3.2–3.4 × 2.8–3.0 mm, significantly narrower than hypochile, adaxially glabrous, margin entire, apex obtuse and slightly denticulate; hypochile globose, with 5 ridges on the distal surface, 5.0– 5.5 mm tall, 4.2–4.5 mm in diameter. Column stout with purple spots, ca. 1.0 mm; rostellum bilobed with acuminated tip; pollinia 2, subglobose, ca. 0.3 mm in diamter; stipe elongate, ca. 1.0 mm; viscidium elliptic, thick and bilobed; anther cap galeate, apex narrowed into a beak. Capsules cylindrical, 3.2–3.5 × 1.4–1.6 mm.

Distribution and ecology:— The new species has only been found in Malipo County, Yunnan Province, China. It probably also occurs in Vietnam, since the type location is adjacent to the border between the two countries. Gastrochilus labrosus was seen on the tree trunks at altitudes from 1850 to 1970 m in the limestone broad-leaved forests. Gastrochilus labrosus was observed flowering from July to August in the wild.

Etymology— The specific epithet refers to the epichile is significantly narrower than hypochile of labellum.

Taxonomic discussion:— On the basis of morphological characteristic, the new species should be placed in sect. Gastrochilus ( Tsi 1996) . However, the phylogenetic study indicates that species in clade III characterized by having long (10–15 cm in length) and slender stems (4–5 mm in diameter), falcate leaves with purple spots, medium-sized flowers (dorsal sepal 5–7 mm in length) and a slightly papillate epichile ( Liu et al. 2019). Therefore, G. labrosus should be clustered into the clade III with its related species.

Figures

FIGURE 6. Gastrochilus labrosus Q. Liu & X.H. Jin, sp nov. A. Habitat. B. Plant with flowers and fruits.C. Inflorescence.D & L.Abaxial and adaxial leaf. E. Flower. F. Sepals and petals. G & H. Front and lateral view of labellum. I. Back view of lip. J. Pollinarium. K. Anther cap.