Scientific name: Phreatia densiflora English name: Vietnamese name: Thủy điềm hoa dàyOther name: Phreatia stenostigma Schltr., Phreatia myosurus (Rchb.f.) Lindl., Eria stachyurus Rchb.f., Eria myosurus Rchb.f., Dendrolirium densiflorum Blume;
Phreatia densiflora (Blume) Lindl. var. vietnamensis Aver.
Perennial epiphytic or occasionally lithophytic herb. Stem erect, not pseudobulbous, (0.5)1–2.5(3) cm tall, (4)5–10(12) mm in diam., covered by imbricate, distichous leaf sheaths and their fibrous remnants. Leaves (3)4–8(10), sessile, with articulation, conduplicate, oblong, ligulate, (4)6–15(18) cm long, (3)4–8(10) mm wide, with two large, unequal, rounded lobes. Inflorescence as long as leaves, shorter or little longer, (8)10–16(18) cm tall, scape as long as rachis. Floral bracts pale yellowish-brown, scarious, (2)2.5–4.5(5) mm long, with broad base, 0.5–1 mm wide, suddenly narrowing into acuminate to filiform apex. Pedicel and ovary 2.5–3(0.4) mm long, ovary narrowly ovoid, 0.5–0.6 mm in diam. Flowers spirally arranged or slightly secund, nectariferous, placed close together, pure white, widely opening, (2)2.2–2.4(2.5) mm across. Sepals and petals broadly ovate, 0.8–1 mm long, lateral sepals slightly oblique and concave at the base. Lip glabrous, sigmoid, 1–1.2(1.4) mm long, 0.7–1 mm wide, slightly longitudinally concave and narrowing to the base, blunt to obtuse, rarely obscurely 3-lobed at apex.
Varietal epithet refers country of its main distribution.
Habitat, phenology and conservation status
Epiphytic or occasionally lithophytic erect miniature herb. Primary broad-leaved and mixed evergreen shady forests on granite, gneiss and limestone, commonly on mossy substratum on mountain tops or along stream valleys. 500–1500 m. Fl. March–May.
Estimated IUCN Red List status – DD.
Vietnam provinces: Khanh Hoa (Hon Ba Mountains; Khanh Son district), Kon Tum (Kon Tum town area), Lam Dong (Lac Duong district) and Quang Binh (Minh Hoa district).