Perennial herbs with rhizomes, corms or bulbs. Leaves usually distichous, equitant, base sheathing. Inflorescence generally racemose or paniculate or reduced to 1-3 flowers, subtended by 1 or 2 bracts (spathe). Flowers actinomorphic or zygomorphic, bisexual. Perianth biseriate, petaloid, inner and outer tepals (or perigone segments) similar or different, free or united into a basal solid hypanthium, well developed or reduced. Outer segments are known as falls and the inner ones as standard. Stamens 3, opposite the outer tepals. Ovary inferior, mostly 3-locular, placentation axile; style usually trifid, frequently petaloid. Fruit a loculicidal capsule. Seeds globose to ellipsoid or pyriform, variable in shape, sometimes arillate.