Gastrochilus obovatifolius C. Xiong, X. Y. Fu & S. R. Yi, 2025

Gastrochilus obovatifolius C. Xiong, X. Y. Fu & S. R. Yi sp. nov.

Figs 3 View Figure 3 , 4 View Figure 4

Diagnosis.

Gastrochilus obovatifolius is most similar to G. balangshanensis ., but differs by the longer stem (3–5 vs. 1.5–3.5 cm), obovate leaves (vs. nearly elliptic), and smaller sepals (ca. 5.0 × 3.0–4.0 vs. 5.6–6.4 × 4.8–5.2 mm) and hypochile (4.0–4.5 × 4.0–4.2 vs. 6.0–8.0 × 5.8–7.5 mm).

Type.

China • Chongqing: Chengkou County (城口县), Dong’an Town (东安镇), Lizishuping (栗子树坪), 31°42′N, 109°11′E, alt. ca. 1650 m, 30 March 2024, Si-Rong Yi et al. YSR 2703 (holotype IBK!, isotype CGMC!) GoogleMaps .

Description.

Epiphytic herbs, monopodial, pendent, with a short stem, 3.0–5.0 cm long, leafy. Roots vermiform, slender, 4.0–6.0 cm long and ca. 1 mm in diameter. Stems short, branched, green, glabrous, up to 5 cm long and ca. 2.0 mm in diameter, covered with sheathing leaf bases; sheaths with purplish-red spots; internodes 1.2–1.8 mm long. Leaves alternate, distichous, obovate, fleshy, 1.4–1.6 × 0.6–0.8 cm, margin entire, apex acute, obscurely serrate; young leaves yellow-green with a few purplish-red spots, mature leaves green with hardly any purplish-red spots. Inflorescences 1–2 racemes, usually arising from the axil of an upper leaf, 2.0– 2.5 cm long, 1–2 - flowered; peduncle 0.8–1.2 cm long; bracts 1.0–2.0 mm long. Flowers 1.2–1.4 × 1.0– 1.2 cm, yellow-green, with dark purple stripes on petals and sepals, raised abaxially along the midrib; pedicel and ovary yellowish-green with purple-red spots, 1.5–1.6 cm long. Dorsal sepal elliptic, concave, ca. 5.0 × 4.0 mm, apex obtuse; lateral sepals similar to dorsal sepal, slightly oblique, ca. 5.0 × 3.0 mm, apex obtuse; petals oblong, concave, ca. 6.0 × 3.0 mm, apex obtuse. Labellum epichile reniform, yellow-green with purplish-red spots, 1.0–1.2 × 0.6–0.8 cm, revolute, margin erose, smooth and glabrous above, median patch, thickened, with 2 low ridges, dark purple; hypochile sub-hemispherical, yellow-green, mouth with lateral purplish-red markings, sac with purplish-red spots on the underside, obtuse at the apex, 4.0– 4.5 mm tall, 4.0– 4.2 mm in diameter, dorsally compressed, slightly bent outward. Column stout, ca. 2.0 × 1.2 mm; rostellum bilobed; anther cap galeate with curved emarginate beak, ca. 1.0 × 1.2 mm; pollinia 2, ca. 0.8 × 0.6 mm, yellow, nearly spherical, entire, with a depression in the center; stipe elongate, ca. 1.2 mm long, viscidium yellow, elliptic, ca. 0.8 × 0.4 mm. Capsule not seen.

Phenology.

Flowering from March to April.

Etymology.

The specific epithet ‘ obovatifolius ’ refers to the highly distinctive obovate leaves. The suggested Chinese common name is “ dào luǎn yè pén jù lán (倒卵叶盆距兰) ”.

Distribution and ecology.

The new species has only been recorded in Chengkou County, northeast Chongqing Municipality, bordering Shaanxi Province, China (Fig. 6 View Figure 6 ). It grows as a trunk epiphyte on Quercus engleriana Seemen , in evergreen broad-leaved forest at an elevation of 1620–1650 m a. s. l. (Fig. 5 View Figure 5 ). Besides Q. engleriana , the most frequent co-occurring angiosperm species include Fargesia spathacea Franch. , Hepatica henryi (Oliv.) Steward , Pieris japonica (Thunb.) D. Don ex G. Don , Rhododendron adenopodum Franch. , and Zanthoxylum dimorphophyllum Hemsl.

Additional specimens examined (paratypes).

China • Chongqing: Chengkou County (城口县), Dong’an Town (东安镇), Dongjiachang (董家厂), 31°42′N, 109°12′E, alt. ca. 1620 m, 8 April 2024, Si-Rong Yi et al. YSR 2733 ( IBK!, CGMC!) GoogleMaps .