Plants 20-100 cm tall, with sessile tuberoids. Leaves cauline or crowded near base. Inflorescence with few white flowers, some very large. Perianth segments subequal. Labellum spurred, ± 3-lobed; side-lobes sometimes conspicuously developed and laciniate or entire or insignificant. Column stout and broad, 4-15 mm high. Anther with very broad connective; anther-cells diverging, slender, gradually narrowed into up to 5 mm long canals. Stigmata forming 2 diverging fleshy swellings, fused along their whole length with the margins of the stigmatic cavity. Rostellum flat, rather obscure.