Herbaceous, climbing vines. Stem terete, fleshy, several meters long,
with an aerial root and a leaf at each node. Leaves fleshy, shortly petiolate.
Racemes axillary, several to many flowered. Flowers resupinate, often large,
rarely minute. Sepals and petals similar, free, spreading. Lip often joined to
sides of column with its basal margin, sometimes almost to top of column,
trumpet-shaped, free part often dilated, spurless, sometimes 3-lobed, disk
often with hairy appendages adaxially. Column long, slender, slightly curved
near top; anther inserted pointing downward; pollinia 2 or 4,
granular-farinaceous, without caudicle or viscidium; rostellum often broad,
below anther. Fruit cylindric, fleshy, often indehiscent. Seeds with stout
testa, black, wingless.