Scientific name: Schoenorchis hangianae Aver. et N.V.DuyEnglish name: Vietnamese name: Nang lan hằngOther name:
Short-creeping epiphyte; stem simple or branching, creeping, to 18 cm long, 3–5 mm wide with internodes to 12 mm long; leaves distichous, narrowly ovate, fleshy, broadly crescent in cross section, 1–1.8 cm long, 5–10 mm wide, oblique bilobe at apex, finely pustulate-verruculose; inflorescence lateral, raceme, to 6 cm long, with few distant flowers; flowers 3–3.5 mm across, sepals, lip and spur white sometimes with purple tint; petals, column and anther cap yellow; median sepal broadly ovate, 1.8–2 mm long; lateral sepals oblique, semicircular, 2.5–3 mm long; petals oblong narrowly obovate, 1.6–2 mm long; lip spurred, 4–5 mm long, 3-lobed; side lobes rectangular, erect, 1.5–2 mm tall, median lobe narrowly ovate, 2.5–3 mm long, with large bilobulate callus at middle and thin up-curved lamellate apex, with bilobulate callus at the base of median lip lobe and large entire callus at the lip base, spur saccate, at right angle, (2–)2.5(–3) mm long, with incomplete longitudinal septum; column small, at front with 2 large, acute, protruding rostellum arms; anther cap in form of twin hemispheres, with large, S-curved beak; viscidium very large, boat-shaped, forward protruding, 1.4–1.6 mm long, 0.5–0.6 mm wide; pollinia 2, each half-split into 2 unequal hemi-obovoid portions.
Perennial short-creeping monopodial epiphytic herb. Stem simple or branching, rigid, creeping, often curved or flexuose, slightly laterally compressed, (3–)4–14(–18) cm long, 3–4.5(5) mm wide, with distichous leaves and wiry flexuose roots arising from internode opposite leaf axil, internodes (2–)3–12(–14) mm. Leaves narrowly ovate, straight, fleshy, succulent, indistinctly conduplicate, broadly crescent in cross section, (1–)1.2–1.6(–1.8) cm long, (5–)6–8(–10) mm wide, 1.5–2(–2.5) mm thick, blunt and oblique bilobe at apex, finely alveolate-verruculose, dark green, often with purple tint; leaf sheath of young leaves smooth to finely verruculose, light green with purple marks, old sheaths green-purple or purple-brown, transversally finely wrinkled. Inflorescence lateral, straight raceme, (2–)3–5(–6) cm long, arising from stem opposite leaf axil, scape and rachis dull purple; scape (1–)1.5–2.5(–3) cm long, with 1–3 small distant, ovate, sterile bracts; rachis (1–)1.5–5(–6) cm long, slightly zig-zag curved, with few lax, spirally arranged flowers distant on (3–)4–5(–6) mm. Floral bracts dark purple, minute, triangular, acute, 0.8–1.2 mm long and wide. Pedicel and ovary cylindric, 4–5 mm long, 0.5–0.8 mm in diam., dull purple to dark purple-violet, slightly broadening and curved toward the apex. Flowers broadly campanulate, 3–4(–5) mm across; sepals, lip and spur white, sometime tinged with purple; petals, column and anther cap yellow. Median sepal erect, broadly ovate, 1.8–2 mm long, 1.5–1.8 mm wide; lateral sepals reflexed, very oblique, semicircular, 2.5–3 mm long, 1.6–1.8(–2) mm wide. Petals oblong narrowly obovate, slightly reflexed, 1.6–2 mm long, 0.8–1 mm wide, undulate and finely erose dentate along margin. Lip spurred, 4–5 mm long and wide being flattened, 3-lobed; side lobes rectangular, erect, fleshy, 1.5–2 mm tall, 2.2–2.4 mm wide; median lobe narrowly ovate, 2.5–3 mm long, 0.8–1 mm wide, with large bilobulate callus at middle and thin up-curved lamellate apex finely erose or notched at apex; disk fleshy, with twin-tops bilobulate callus at the base of median lip lobe and large entire callus at the lip base at spur entrance; spur narrowly obovoid, saccate, slightly dorso-ventrally flattened, down curved at right angle, (2–)2.5(–3) mm long, 1.2–1.5 mm broad, at apex round and slightly notched, inside with incomplete short longitudinal septum. Column small, about 0.5 mm high and wide, at front with 2 large, acute, knife-shaped parallel, forward directed rostellum arms, 1–1.2 mm long, 0.3 mm wide at the base. Anther cap in form of twin hemispheres, finely papillose, 1–1.2 mm wide and 0.5–0.6 mm tall, with large, oblong triangular, scarious, S-curved beak 0.6–0.8 mm wide, 0.8–1 mm long. Stipe (tegula) simple, small, in form of flat, erect triangular plate, 0.2–0.3 mm long and wide; viscidium very large, concave at apex from below, boat-shaped, forward protruding, 1.4–1.6 mm long, 0.5–0.6 mm wide. Pollinia 2, each half-split into 2 unequal hemi-obovoid portions, 0.3–0.4 mm long. Fruits narrowly ellipsoid capsule 0.8–1.2 cm long, 3.5–4.5(–5) mm in diam., placed more or less horizontally on straight rigid stalk 2–3 mm long.
Etymology:—Species epithet refers to the name of Mrs. Nguyen Thi Thanh Hang, wife of the species discoverer, co-author of this paper — Dr. Nong Van Duy.
Ecology:—Creeping epiphyte; primary broad-leaved, evergreen, humid, submontane forests on granite. 1000 m a.s.l. Fl. May–July. Very rare. Estimated IUCN Red List status—CR.
Distribution:—Vietnam: Khanh Hoa (Khanh Vinh district). Endemic.
Notes:—Schoenorchis hangianae is obviously related to S. scolopendria