Terrestrial or epiphytic herbs. Stems leafy, becoming thickened and pseudobulbose. Leaves distichous, plicate. Sepals free, equal, spreading. Petals similar to the sepals, sometimes broader. Lip entire or bilobed, adnate to the base of the column, with a conspicuous spur at the base; lateral lobes usually erect and enfolded over the column. Column erect, short; anther terminal, operculate, incumbent, imperfectly 2-celled; pollinia 4, ceraceous, often in pairs.