Herbs, epiphytic or lithophytic, pendulous or erect. Pseudobulbs contiguous or well spaced on creeping rhizomes, ovoid to subcylindric, rarely connected to each other at both ends and stemlike or each connected at base by a short rhizome to middle part of another pseudobulb, apex 1- or 2-leaved. Leaves narrowly elliptic, ovate, or oblong, leathery, shortly petiolate. Inflorescence terminal, emerging from apex of pseudobulb, distichous, pendulous, slender, racemose, laxly or densely many flowered; rachis often slightly flexuose; floral bracts persistent or deciduous, distichous, large, concave. Flowers resupinate, often not opening widely, white, small, fleshy. Dorsal sepal concave or convex, broadly ovate to elliptic; lateral sepals ovate to ovate-oblong, concave or convex, often carinate. Petals ovate to linear, often smaller than sepals; lip sessile, with a saccate basal hypochile and subentire or 3- or 4-lobed; epichile deflexed; disk sometimes with thick veins or lamellae. Column short, upper part winged or hooded, foot absent; anther incumbent; pollinia 4, waxy, subequal in size, in 2 pairs, connected by inconspicuous caudicles to sticky material; rostellum rather large. Capsule relatively small, often ribbed.