Gastrochilus heminii M.Liao, B.Xu & Yue H.Cheng, 2022

Liao, Min, Cheng, Yue-Hong, Zhang, Jun-Yi, Feng, Yu, Liu, Gui-Ying, Ye, Ping, Jin, Sen-Long, Lin, Hong-Qiang & Xu, Bo, 2022, Gastrochilus heminii (Orchidaceae, Epidendroideae), a new species from Sichuan, China, based on molecular and morphological data, PhytoKeys 215, pp. 95-106 : 95

Gastrochilus heminii M.Liao, B.Xu & Yue H.Cheng sp. nov.

Figs 2A, B , 3

Type.

China. Sichuan: Wenchuan , coniferous and broadleaf mixed forest, on tree trunk, elev. ca. 2640 m, in flowering and fruiting, 15 March 2022, Min Liao & Yue-Hong Cheng ZJY143 (holotype CDBI!) .

Diagnosis.

Gastrochilus heminii is morphologically related to G. affinis and G. yei based on vegetative and floral characteristics such as similar habit, distichous and alternate leaves, epichile surface smooth and glabrous, sepals and petals with purplish-red patches. However, it can be differentiated from G. affinis on the basis of flower numbers (1-2 in the former vs. 1-4 in the latter), peduncle length (0.4-0.7 cm in the former vs. 1.5-2.0 cm in the latter) and an additional morphological characteristic: young leaves are densely covered with purple-red spots and old leaves have hardly any purple-red spots in the former (both have purple-red spots in the latter); the reniform epichile is rolled downwards, smooth and glabrous above, and central thickened purple-red mat with irregular folds in the former (subtriangular epichile curves upwards, with 2 thick, brown to purplish-brown median ridges from base to apex in the latter). It differs from G. yei by having reniform and lobed epichile (not lobed in the latter), apex of hypochile bilobed and splits into two conical protrusions (not bilobed in the latter), apex of the leaf with 1-2 lobules, lobes setaceous (apex of leaf with a tine in the latter).

Description.

Miniature trunk epiphyte. Roots vermiform, 2.0-7.0 cm long and ca. 1.5 mm thick. Stem pendulous, slender, purplish-red spots, 3.0-6.5 cm long and ca. 1.8 mm thick. Leaves alternate, distichous, narrowly oblong or falcate oblong, 0.9-2.3 × 0.3-0.5 cm, apex acute and with 1-2 lobules, lobes setaceous, young leaves with conspicuous purplish-red spots, old leaves with hardly any purplish-red spots. Raceme with 1 or 2 flowers; inflorescence stalk curved upward and thickened, 4.0-9.0 mm long, proximally covered with two sheaths; floral bracts ovate-lanceolate, 0.7-1.0 mm long, apex acute; pedicel and ovary connate, 4.0-5.5 mm long; flowers spreading, ca. 6.0 × 5.0 mm; sepals and petals heterochromatic on both surfaces, outside yellow-green with purplish-red spots, inside purplish-red with yellow-green margin; dorsal sepals and lateral sepals similar and equal in size, elliptic-oblong, ca. 2.4 × 1.5 mm, apex obtuse; petals narrowly oblong, ca. 2.6 × 1.3 mm, apex acute, base narrowed; epichile reniform, yellow-green with purplish-red spots, 4.2-6.5 × 2.0-3.0 mm, margin erose, smooth and glabrous above, central thickened purple-red mat with irregular folds; hypochile subconical, yellow-green with purple-red spots, 2-2.4 × 1.6-2 mm, dorsally compressed, slightly bent outward, the apex splits into two conical protrusions; column cylindrical, ca. 1.0 mm; anther cap subhemispheric, with two chambers, 0.7 × 0.4 mm, hanging from both ends of the stipe; pollinia 2, 0.4 × 0.3 mm, yellow, full and nearly spherical, with a depression in the center; stigma deeply sunken, inverted V-shaped, ca. 0.6 mm long, yellow, apically forked, forked in a subtriangular outline. Capsule shuttle-shaped with six ribs, green with sparse purplish-red spots, ca. 1.1 cm long, inflated to ca. 0.6 cm in the middle, persistent and growing for one year until maturity.

Additional specimens examined.

- China. Sichuan: Wenchuan , coniferous and broadleaf mixed forest, on tree trunk, elev. ca. 2640 m, 18 April 2022, Min Liao & Yue-Hong Cheng ZJY167 (CDBI) .

Distribution, habitat and phenology.

The new species is currently known only from Wenchuan County, Sichuan Province, Southwest China (Fig. 4 ). It is found epiphytic on the trunk of Tsuga chinensis (Franch.) Pritz. in a subalpine mixed coniferous forest at elevation ca. 2640 m. Gastrochilus heminii flowers from March to April.

Etymology.

Named in honor of Mr. He-Min Zhang, the advocate of the panda "Release to the Forest", one of the pioneers of panda research in China, renowned as the “father” of pandas, in recognition of his contribution to the conservation of flora and fauna in the region which was one of the earliest reserves dedicated to preserving the habitat of wild pandas. A Chinese name, he min peng ju lan (和民盆距兰), is suggested here.

Conservation status.

Three populations with a total of ca. 200 individuals of Gastrochilus heminii have been documented during our investigation. However, similar habitat of this new species is widespread in the Wolong Natural Reserve. Therefore, we assessed the conservation status of Gastrochilus heminii as DD (Data Deficient) according to the IUCN (2022).

Figures

Figure 2. Comparison of three taxa of Gastrochilus A, B Gastrochilus heminii C, D G. affinis E, F G. distichus G, H G. yei. [Images C, D cited from Jalal et al. 2020; image E reproduced from website (http: // www. orchidspecies. com / gastdistichus. htm); image F cited from Kumar et al. 2014, which was photographed by Xiao-Hua Jin; images G and H cited from Li et al. 2021].

Figure 3. Gastrochilus heminii A flowering plant B young leaves (B 1: front view; B 2: reverse view) C old leaves (C 1: front view; C 2: reverse view) D raceme and capsule (side view) E-I flowers (different views) J anatomy of flower (J 1: dorsal sepals; J 2 and J 3: lateral sepals; J 4 and J 5: petals; J 6: labellum) K hypochile (dorsal view) L stamens.

Figure 4. Distribution map of Gastrochilus heminii.