Description from Flora of China

Aplostellis Thouars; Bolborchis Zollinger & Moritzi; Cordyla Blume (1825), not Loureiro (1790); Roptrostemon Blume; Stellorkis Thouars.

Herbs, terrestrial. Tubers globose or ovoid, cormlike, fleshy, few to several noded, with a few short roots at nodes or rootless. Stem arising from apex of tuber and giving rise to an inflorescence and a leaf in succession, bearing 1 to several lateral, subterranean runners during leafing period. Runners producing new tubers at apex. Leaf solitary, usually emerging after anthesis, usually horizontal, cordate, orbicular, reniform, or elliptic, palmately veined, often plicate, membranous or fleshy, glabrous or pubescent, base cordate, apex acute, obtuse, or rounded, borne on an elongate, erect or prostrate petiole-like stalk. Inflorescence erect, terminal, slender or slightly stout, usually slightly fleshy, glabrous; peduncle with 1 to several tubular sheaths, elongating in fruit in 1-flowered species; rachis 1-, 2-, or several flowered; floral bracts usually small, lanceolate. Flowers erect or nodding, resupinate or not, medium-sized, opening widely or not; pedicel becoming erect and elongating in fruit in 1-flowered species. Sepals and petals similar, narrowly ovate or elliptic; lip 3-lobed or occasionally simple, base spurless or spurred, apex entire or fimbriate. Column elongate, clavate, slender, not winged; anther terminal, incumbent, usually ovoid, 2-locular; pollinia 2, cleft, granular-farinaceous, sectile; caudicle absent; viscidium reduced or prominent; rostellum broad, entire, sometimes absent; stigmatic surface shield-shaped to orbicular, lying below rostellum.

This is a taxonomically problematic genus that remains poorly understood, primarily because the solitary inflorescence and solitary leaf usually emerge and are present aboveground at different times in the growing season, frequently leading to incomplete herbarium collections and species circumscriptions. Some of the widespread taxa may represent species complexes and are in need of critical re-examination.