Perennial herbs, roots with stalked or sessile tubers. Leaves radical, linear, flat, often withering early; leaf fibres from previous seasons often present. Inflorescence racemose or paniculate, scapose; flowers usually 1-9 per node, sometimes secund; pedicels spreading to nodding, usually articulate. Tepals free, rotate to reflexed, not twisting after flowering, pale blue, purple or white; outer tepals narrow, 3-5-veined; inner tepals elliptic to circular. Stamens 6; filaments hirsute; anthers introrse to latrorse, dehiscing by longitudinal slits. Ovules 1-5 per loculus; style simple. Fruit a capsule, sometimes enclosed by perianth; seeds globose to angular, black.