Lateral sepals often oblanceolate and asymmetric at the base, usually longer than the dorsal sepal.
Leaves distichous, ligulate to oblanceolate, often falcate, unequally 2-lobed at the apex.
Column short; rostellum 3-lobed or bifid; pollinia 2, stipites 2; viscidia 2, rarely 1.
Petals usually smaller, triangular, often adnate to lateral sepals at the base.
Flowers small, white, green or yellow, with a relatively long pedicel.
Inflorescences axillary, racemose, few-to many-flowered.
Lip entire or 3-lobed, ecallose, spurred.
Bracts small, sheathing at the base.
Small, epiphytic, monopodial herbs.