Gastrochilus lihengiae J.D.Ya, Ting Zhang & Z.D.Han, 2023

Ya, Ji-Dong, Wang, Wan-Ting, Liu, Yun-Long, Jiang, Hong, Han, Zhou-Dong, Zhang, Ting, Huang, Hua, Cai, Jie & Li, De-Zhu, 2023, Five new and noteworthy species of Epidendroideae (Orchidaceae) from southwestern China based on morphological and phylogenetic evidence, PhytoKeys 235, pp. 211-236 : 211

4. Gastrochilus lihengiae J.D.Ya, Ting Zhang & Z.D.Han sp. nov.

(纤细盆距兰 Xian Xi Pen Ju Lan) Figs 8 , 9

Diagnosis.

The floral morphology of Gastrochilus lihengiae is similar to G. distichus (Lindl.) O. Kuntze and G. prionophyllus H. Jiang, D. P.Ye & Q. Liu, but can be distinguished from the former by its narrower leaves, blades 0.25-0.35 cm wide (vs. 0.4-0.6 cm), and distinctly serrate leaf margins (vs. entire), with acuminate and mucronate apices (vs. apex acute bearing 2 or 3 awns). The lateral petals are narrowly oblong (vs. subobovate). The labellum with a hypochile, ca 7.0 mm (vs. 4.0 mm). The outside of the hypochile with three ridges (vs. glabrous), and from the latter by its falcate-lanceolate (vs. ovate) leaves with mucronate apices (vs. apex with 2 unequally awns), the lateral petals are narrowly oblong (vs. subobovate), the central cushion on the epichile of the labellum is not thickened (vs. thickened), while the outer surface of its hypochile has three ridges (vs. glabrous).

Type.

China. Yunnan Province, Nujiang Prefecture, Gongshan County, Cikai Township , 1935 m, in the montane moist evergreen broad-leaved forest, 24 Apr. 2020, J.-D. Ya et al. 22CS21828 (Holotype: KUN! isotype: KUN!)

Description.

Epiphytic herbs, stem pendulous, to 20 cm long, ca. 1.0-1.5 mm in diameter, slender, with 0.5-0.6 cm internodes, often branched with tiny red-purple spots. Leaves alternate, distichous, falcate-lanceolate, ca. 1.6-1.8 × 0.25-0.35 cm, the margin significantly serrate with an acuminate and mucronate apex. Inflorescences several, held opposite to nearly opposite the leaves, subumbellate, 1-3-flowered; peduncle 0.7-1.0 cm, slender, upper part enlarged, lower part with 2 cupular sheaths; floral bracts ovate, ca. 1.0 mm; pedicel and ovary 1.0-1.1 cm. Flowers yellow-green, with reddish brown spots. Dorsal sepal concave, oblong-ovate, ca. 4.0 × 2.0 mm, apex obtuse; lateral sepals concave, narrowly oblong, ca. 5.5 × 1.8 mm, apex obtuse; lateral petals narrowly oblong, 4.0 × 1.8 mm, apices subtruncate. Labellum subdivided into an epichile and a saccate hypochile; the epichile subovate triangular, ca. 5.0 × 2.5 mm, adaxially glabrous, with a central cushion and 2 conic calli near its base, the margin entire to irregularly denticulate, apex rounded; the hypochile subcupular, ca. 7.0 mm tall and ca. 5.2 mm in diam. outside with three ridges from the base of the column to its apex. Column stout, ca. 2.0 mm long, with rounded-auriculate wings at the base; anther cap narrowed into a beak towards its apex; the rostellum bilobed with an acuminate tip, and a horn-like awn arising from the center of each lobe; pollinarium ca 2.1 mm long; pollinia 2, yellow, 0.8 × 0.5 mm, almost hemispheric with a depression at the center; stipe elongate, obovate, ca.1.5 mm long; cellular viscidium elliptic, 1.0 × 0.5 mm. Capsules cylindrical, ca. 1.5 × 0.6 cm.

Phenology.

Flowering from March to April, while the fruits matured in March in the following year.

Etymology.

Named in honor of late Prof. Li Heng for her contributions to the orchid flora of Yunnan ( Guo et al. 2023).

Distribution and habitat.

At present, two populations of this new species were found in Gongshan County, Yunnan, China. It is epiphytic on tree trunks in the mixed evergreen broad-leaved forest or montane moist evergreen broad-leaved forest at an elevation of 1900-2100 m.

Additional specimens examined.

China. Yunnan Province, Nujiang Prefecture , Gongshan County, Dulongjiang Xiang, 2051 m, in the mixed evergreen broad-leaved forest, 4 Mar. 2023, Ting Zhang et al. 23CS24145 (paratypes, KUN!). G. distichus : India. Skimm, J.D. Hooker 206. (holotype: K000873754!). G. prionophyllus : China. Yunnan, Malipo County, Xia jinchang town, limestone forest, 1550-1650 m a.s.l., epiphytic on tree trunks or on rocks, 15 Mar. 2016, Qiang Liu 359 (holotype, HITBC!). G. fargesii : China. Sichuan, Tschen-keou-tin, P.G. Farges 1236 (type, K00083803! isotype, AMES00271835!) .

Figures

Figure 8. Gastrochilus lihengiae J. D. Ya, Ting Zhang & Z. D. Han, sp. nov. A flowering plant B fruiting plant; Stem C leaf D inflorescence E-I flower (different view) J adaxial sepals and petals K abaxial sepals and petals L column and lip M, N lip (rip cutting) O, P column Q pollinarium R anther cap. Photographed by J. - D. Ya & Z. - D. Han.

Figure 9. Gastrochilus lihengiae J. D. Ya, Ting Zhang & Z. D. Han, sp. nov. A plant B flower C sepals and petals D column and lip E epichile F pollinarium G anther cap H leaf. Drawn by Z. - D. Han.