Plants slender or robust, up to 70(-100) cm tall. Rhizome short. Stem leafy throughout. Leaves spreading, ovate to ovate-lanceolate. Inflorescence normally densely many-flowered, up to 25-(35) cm long. Bracts lanceolate, lower exceeding flowers, the upper decreasing in size. Flowers from dark olive-green to yellowish-green, tinged ± intensively with red-purple. Sepals campanulate, ovate-lanceolate, up to 12 mm long; petals slightly shorter, ovate, paler green or pinkish. Labellum with cup-shaped hypochile, outside green, inside dark shining olive-brown, with nectar, 4-6 mm long and broad; epichile cordate, up to 5 mm long, the margin slightly crenulate-undulate, with 2 ± rugose bosses at base. Column short, 4-5 mm (including the anther). Ovary pedicelled, glabrous or with some hairs; ripe seed-capsule spreading.