Aquatic or marsh perennials with + tuberous or rhizomatous stem, scapigerous, with mostly basal leaves only. Leaves rush-like, linear, fleshy, some-what terete, sheathing at the base of scapes. Inflorescence a scapigerous, bractless raceme; scapes leafless, jointless, many-flowered. Flowers small, 3-merous, her¬maphrodite. Perianth segments (perigonium) 6, ovate, concave, deciduous; the inner 3 inserted a little above. Stamens 6, almost sessile, inserted on the base of the segments; anthers ovate, didymous, attached under the middle of the back, opening by extrorse slits. Carpels 6, all fertile or alternate ones sterile, connate but separating at maturity in fruit from below, each locule 1-ovuled; style absent or inconspicuous, connate with short pencillate or plumose stigmas. Fruit of 6 or 3, almost free (often slightly connate at the tip) achenes or follicles, separating from the central axis, incompletely or completely, often with somewhat recurved tips, and at length dehiscent at the ventral angle, each 1-seeded; seed erect, with thin testa and straight embryo.