墨脱柱兰Cylindrolobus motuoensis

Epiphytic herb. Roots terete, slender, pubescent, ca.0.8‒1.0 mm thick. Rhizome inconspicuous. Stem clustered, terete, slender, 4-leaved apically, covered by close-fitting sheaths, 13‒25 cm long, 3‒4 mm thick. Leaves lanceolate, acuminate, 4.5‒6.5 cm long, 0.8‒1.5 cm wide. Inflorescences axillary, glabrous, arising from the apical of the stem, 1.3 cm long, 2-flowered; peduncle 0.5 cm long; sterile bracts 1‒2, smaller. Flowers yellow, sepal externally reddish yellow, 7‒8mm long; floral bracts yellowish green with red brown edges, obovate, mucronate, concave, glabrous, 4 mm long, 2.5 mm wide; peduncle and ovary ca. 4‒6 mm long. Dorsal sepal lanceolate, obtuse, 3 veined, 6 mm long, 2 mm wide; lateral sepals falcate-ovate, obtuse, 3-veined, 5 mm long, 3.5 mm wide, base adnate to column foot form a subglobose and obtuse mentum; petals oblong-ovate, slightly oblique at base, obtuse, 1 veined, 5 mm long, 2 mm wide; labellum oblong in outline, 3-lobed, base hinged to the apex of the column foot, apex emarginate, ca.3.5 mm long, 1.5 mm wide; lateral lobes suberect, subovate, apex slightly introvert, disk with 2 reddish brown calli; mid-lobe sub-square, ca. 3.3 mm × 2 mm, lateral margins thickened and erect, with a central papillate keel, reddish brown, ca. 0.5 mm high; apex emarginate. Column semiterete, ca. 3.5 mm long, narrow winged at ventrally; rostellum triangle, 0.2 mm, a hook-like protrusion under the stigma; foot incurved, ca. 4 mm; cap subrotund, ca. 0.6 mm × 0.6 mm, papillate and protrude in front; pollinia 8, yellowish white, compressed subrotund from the lateral view, anterior 4 ca. 0.2 mm × 0.2mm × 0.1mm, posterior 4 smaller. Fl. April-May.