Perennial, or rarely annual,
marshy grass-like herbs, tufted, with
short rootstock, roots fibrous. Leaves radical, linear, sheathing.
Inflorescence terminal, globose to cylindric head or dense spike, on scape-like
peduncles, bracts spirally imbricate, persistent, lower empty, upper enclosing
solitary flower. Flowers bisexual, sligtly zygomorphic, white or yellow,
3-merous. Sepals 3, lateral 2 small, keeled, median cap-shaped, enveloping the
corolla. Petals 3, actinomorphic, base clawed, or connate, forming tube.
Stamens 3, opposite petals, staminodes present or absent, filaments
short, adnate to petals, anthers 2-loculed, dehiscing longitudinally. Ovary superior, ovules many, style filiform,
3-fid, stigma capitate. Fruit oblong capsule, 3-valved, loculicidal. Seeds
longitudinally ribbed, embryo small.