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

Gastrochilus obovatifolius C. Xiong, X. Y. Fu & S. R. Yi sp. nov. Figs 3, 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!). 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). 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). 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!).