Gastrochilus menglaensis Q. Liu, Jian W. Li & 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 : 211

Gastrochilus menglaensis Q. Liu, Jian W. Li & X.H. Jin , sp. nov. (ƦOififfi±) ( Figure 1–2 )

Type:— CHINA. Yunnan Province: Mengla County, Yiwu town. Mountain rainforest, 1000 m, 15 October 2010, Jian-Tao Yin 1874 (holotype: HITBC!) .

Morphologically, Gastrochilus menglaensis is similar to G. somae ( Hayata 1914: 93) Hayata (1915) and G. hainanensis Z.H. Tsi (1989: 21) , particularly in the same erect and stout stem, epichile of lip with a reverse T-shaped groove at its base. But the new species could be distinguished from latters by having membranous sepals and petals, spatulate petals and sepals and petals with markedly 1-ridge in the middle.

Description:— Epiphytic herbs. Stem erect, 1.5–2.0 cm long and 5.0 mm in diameter, with 4–5 leaves. Leaves nearly basal, distichous, blade falcate-oblong, 5.5–7.0 × 1.0– 1.2 cm, fleshy, apex obtuse and unequally 2-lobed. Inflorescences subumbellate, 5–6-flowered; peduncle straight, 5.0–6.0 mm, stout; floral bracts ovate, ca. 3.0 mm; pedicel and ovary 8.0–9.0 mm. Flowers with faint yellow and membranous sepals and petals, and white lip with purplish or yellow spots. Dorsal sepal, obovate- elliptic, 4.0–5.0 × 2.0– 2.2 mm, markedly 1-ridge in the middle, apex acuminate; lateral sepals similar to dorsal sepal slightly narrower; petals spatulate, 4.0–4.2 × 1.5–1.6 mm, markedly 1-ridge in the middle, apex acuminate. Lip with an epichile and a saccate hypochile; epichile subtriangular, 4.0–4.2 × 8.0–9.0 mm, thickly fleshy, glabrous, basal margin membranous and slightly erose, with a large central cushion, and a reverse T-shaped groove at its base, apex rounded, slightly recurved; hypochile subglobose, ca. 5.0 mm tall, 5.5–6.0 mm in diameter, white tinged with yellow at bottom and purplish blotches on margin, outside with 5 ridges. Column ca. 1.0 mm, stout; rostellum deeply 2–lobed; pollinia 2, ca. 1.0 mm in diameter; stipe elongate, ca. 1.5 mm; anther cap nearly subglobose, apex narrowed into a beak.

Distribution and ecology:— Until present, this new species is known only from Mengla County, Yunnan Province, China and Namta Province, Laos. Gastrochilus menglaensis grows on tree trunks at altitudes from 720 to 1100 m in tropical mountane rainforest. Gastrochilus menglaensis was observed flowering in October in the wild.

Etymology:— Referring to the type locality, Mengla County, Yunnan Province, China.

Additional specimens examined (paratype):— LAOS. Namta Province: Louang Namtha National Natural Reserve, Mountain rainforest, 720 m, 20 October 2019, Shi-Shun Zhou 15855 ( HITBC!) .

Taxonomic discussion:— On the basis of the stout (c.> 5 mm in diameter) stem, Gastrochilus menglaenensis can be placed in section Gastrochilus ( Tsi 1996) . However, the recently phylogenetic study shown that sect. Gastrochilus was well supported to divided into three clades, and G. somae was clustered into clade III 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). Actually, the new species and G. somae should cluster into clade I by having short (<2 cm in length) and stout (c. 6 mm in diameter) stems, leaves equally bilobed at the apex and large flowers (dorsal sepal> 8 mm in length) and a non-fimbriate, nonpapillate epichile ( Liu et al. 2019). Therefore, it still needs to establish the robust classification schemes to resolve the infrageneric relationships of Gastrochilus in the further phylogenetic study.

Figures

FIGURE 1. Gastrochilus menglaensis Q. Liu, Jian W. Li & X.H. Jin, sp. nov. A. Habitat (mountain rainforest); B & C. Plant. D. Inflorescence. E. Front view of lip. F. Flower. G. Back view of lip. H. Dorsal sepal, lateral sepal and petal. I. Pollinarium. J. Anther cap.

FIGURE 2. Illustation of plant and Inflorescence with flowers for Gastrochilus menglaensis (A), G. somae (B) and G. hainanensis (C).