Polystachya vaginata Summerh.

An erect epiphytic or rarely lithophytic plant up to 50 cm. high.. Stems approximate, pseudobulbous, narrowly cylindric-conical, 1–3 cm. high, 5–10 mm. diameter, covered with a few acute scarious sheaths, 2–3-leaved above.. Leaves suberect, ligulate-linear, rounded and obscurely bilobed at apex, 5–25 cm. long, 3–8 mm. wide.. Inflorescence often very much longer than the leaves, simply racemose or several-branched, 7–48 cm. high; peduncle 5–23 cm. high, covered with flattened acute sheaths; rhachis bearing up to 7 secund branches, each to 2–5-flowered, bare rhachis densely pubescent; bracts lanceolate, acuminate, 3–7 mm. long.. Flowers erect-spreading, straw-coloured to light brown; pedicel and ovary 5–10 mm. long, densely pubescent.. Dorsal sepal slightly incurved, lanceolate or oblong-lanceolate, acute, 6.5–9.5 mm. long, 2–4.5 mm. wide; lateral sepals obliquely and narrowly triangular, acuminate, 8.5–11.5 mm. long, 5–5.5 mm. wide; mentum incurving, cylindric-conical, rotund, 3.5–4.5 mm. long; sepals all sparsely pubescent on outside.. Petals obliquely oblanceolate, acute, 6–8.5 mm. long, 1.5–2 mm. wide.. Lip recurved, shortly clawed, 3-lobed at or above the middle, 7.5–9.25 mm. long, 5.25–6 mm. wide; side lobes erect, rotund-triangular, clavate-hairy in front; mid-lobe recurved, ovate or broadly ovate, acuminate-apiculate, 2.5–4 mm. long, 3–3.25 mm. wide, margins undulate, densely clavate-hairy in centre.. Column porrect, semiterete, 2.5 mm. long.