(Plates 91-96; Fig. 672.1-672.4) Terrestrial, lithophytic, and epiphytic herbs. Roots terete or flattened. Stem leafy, concealed by overlapping persistent leaf-sheaths, rooting mostly at base. Leaves alternate, distichous, succulent, persistent or sometimes deciduous, oblong to broadly elliptic, sometimes marbled or suffused with purple or silver. Inflorescence axillary racemes or panicles, axillary, erect to pendent; peduncle terete; rachis terete or bilaterally compressed, rarely swollen relative to peduncle; floral bracts usually inconspicuous, persistent, succulent or papery. Flowers 1–30, resupinate, produced simultaneously or in succession, often long-lasting, sometimes fragrant, plain or variously spotted, marbled, or barred. Sepals and petals free, spreading, subsimilar to dimorphic, lateral sepals usually oblique and larger than dorsal sepal. Labellum trilobed, clawed, continuous with column foot or rarely hinged at base of a footless column (species formerly included in Hygrochilus), sometimes saccate-spurred or subsaccate, side lobes erect and subparallel, often callose, midlobe oblong-elliptic to obtrullate, rarely transverse, sometimes pubescent to villose, apex sometimes bearing a pair of tendril-like appendages (cirrhi), callus uni-, bi- or triseriate, longitudinal, rarely transverse; sac or spur, if present, without internal ornamentation. Column often subtended by a pair of fleshy, knee-like protrusions, without wings, usually with a column foot, usually dilated lateral to stigma; pollinia two or four, on a common spatulate stipe and viscidium; rostellum sometimes beaked. Ovary pedicel terete, shallowly six-sulcate.