Tufted, glabrous herbaceous perennials. Roots tuberous, or fleshy-fibrous or fibrous with or without tubers. Leaves linear, ± radical. Inflorescence paniculate; axis simple or branched, bracteate; lower bracts leaf-like, upper minute. Flowers bisexual, actinomorphic, pedicellate, distinctly clustered. Perianth ± petaloid; segments 6, subequal, 3-nerved, shortly connate, spirally twisted after flowering, ultimately deciduous. Stamens 6; filaments ± slender, papillose, alternately long and short; anthers dehiscing introrsely by slits. Ovary superior, 3-locular; ovules 2 per locule; placentation axile; style filiform; stigma capitate, minute. Fruit a loculicidal capsule, ± 3-lobed, tardily dehiscent. Seed often 1 per locule, ±globose; aril papery; testa smooth, striate, or granulate and often tuberculate, black.