Scientific name: Phreatia formosana Rolfe in Hemsl.English name: Vietnamese name: Thủy điềm đài loanOther name: Phreatia evrardii Gagnep.;
Phreatia formosana Rolfe ex Hemsl. var. continentalis Aver.
Perennial epiphytic herb. Stem erect, not pseudobulbous, (0.5)1–1.5(2) cm tall, (2)3–5(7) mm in diam., covered by imbricate, sub-distichous leaf sheaths and their fibrous remnants. Leaves (4)6–8(10), sessile, with articulation, conduplicate, oblong, ligulate, (3)4.5–10(12) cm long, (5)7–10(12) mm wide, obtuse or obscurely hardly bilobed at apex. Inflorescence much longer than leaves, (7)8–16(18) cm tall, scape as long as, or shorter than rachis. Floral bracts pale yellowish-brown, scarious, narrowly triangular ovate, (1.5)2–3(3.5) mm long, tapering to acute apex. Pedicel and ovary 2.5–3 mm long, ovary narrowly ovoid, 0.6– 0.7 mm in diam. Flowers spirally arranged or slightly secund, placed close together, pure white, campanulate, (2)2.2–2.5(2.6) mm across. Sepals and petals, fleshy, broadly ovate, (1.2)1.4–1.5(1.6) mm long, lateral sepals slightly oblique and concave at the base. Lip (1)1.2– 1.3(1.4) mm long, (0.8)1–1.1(1.2) mm wide, distinctly divided into concave, almost hemispheric hypochile and broad transversely broadly lunate epichile, densely papillose at center, entire and round at apex, often slightly undulate along margin.
Varietal epithet refers its mainland distribution.
Habitat, phenology and conservation status
Epiphytic erect miniature herb. Primary broad-leaved evergreen forests on limestone, shale, granite and gneiss, commonly as branch epiphyte on mossy trees on mountain tops, very steep slopes or along humid canyons. 500–1400 m. Fl. March–August.
Estimated IUCN Red List status – DD.
Vietnam provinces: Ha Giang (Bac Me district), Kon Tum (Ngoc Linh Mountains; Kon Plong district), Lam Dong (Dalat City area) and Quang Binh (Minh Hoa district).