Achasma Griffith; Diracodes Blume, nom. rej.; Geanthus Reinwardt (1828), not Rafinesque (1814) nor Philippi (1884); Nicolaia Horaninow, nom. cons.

Rhizomes creeping. Pseudostems robust. Leaves petiolate, lanceolate, large. Inflorescence arising from rhizomes, a spike or head with flowers arranged in 3 or 4 concentric circles on a flat receptacle, base surrounded by numerous sterile, involucral bracts; peduncle raised well above ground and long, or embedded in ground and short; bracts 1-flowered; bracteoles long tubular. Calyx tubular, membranous, split on 1 side, apex 3-toothed. Corolla tube equaling or longer than calyx; lobes 3, much shorter than tube. Lateral staminodes absent. Labellum tongue-shaped, ± 3-lobed, much longer than corolla lobes, base adnate to filament forming a distinct tube; central lobe colored, apex entire or 2-lobed; lateral lobes basally folded over stamen. Stamen shorter than labellum; free part of filament very short and rather broad; anther bent forward; connective appendage absent. Ovary 3-loculed; ovules numerous per locule. Capsule fleshy, indehiscent, smooth, longitudinally ridged, or with obtuse warts in rows.

About 70 species: China, India, Indonesia, Malaysia, Thailand; N Australia; three species (one endemic, one introduced) in China.