CYPERACEAE  

Perennial, submerged aquatics, rooted in mud. Culms up to 1 m long, nodose with internodes up to 250 mm long. Leaves cauline, eligulate; sheath conspicuous, adaxial apex truncate; blade 0. Inflorescence of compound-whorled branches, mostly sterile. Spikelets emergent, single, terminal on branches; glumes 2, +/- 10 mm long, attenuated, lower empty, upper fertile; floret bisexual. Perianth of 6-11 barbate bristles, longer than nutlet. Stamens 3. Style 2-branched. Nutlet ovate, long-beaked, +/- smooth.

Annuals, small, tufted. Culms with aerial nodes. Leaves basal and cauline, eligulate; sheath with adaxial apex truncate; blade linear, without a keeled midrib, profile thickly crescentiform. Inflorescence with spikelets of 2 kinds: partially subterranean among basal leaves, female; exposed spikelets bisexual, paniculate. Bisexualspikelets greenish, cymose, with 3-5, +/- 2-ranked or distichous glumes, mostly with 2 perfect florets associated with uppermost glumes; perianth of 3 segments, hairy at base, expanded in middle and usually terminated by (1)3 stiff bristles; stamens 3; style 3-branched. Nutlet obovate, 3-angled. Femalespikelets of 2-4, tightly sheathing, sterile, subterranean glumes and one tubular, fertile glume; perianth 0; style 3-branched. Nutlet +/- globular.

Perennials or annuals, tufted, long-stoloniferous or long-rhizomatous, sometimes tuberous. Culms erect, with aerial nodes, generally 3-angled; bases sometimes swollen. Leaves sheathing at base, ligulate or eligulate; sheath with adaxial apex n-shaped or truncate; blade narrow, with keeled midrib, profile V-shaped to flanged V-shaped, margins scabrid. Inflorescence panicled. Spikelets unisexual or bisexual; florets all unisexual; bisexual spikelets with one basal female floret and 1-few male florets above; unisexual female spikelet with single female floret at base and empty glumes above; unisexual male spikelets without female floret at base and often with more than one male floret. Perianth cupular or 0, upper margin frequently irregularly lobed or fimbriate, mostly shed with nutlet. Stamens (1)2 or 3; anthers often apiculate. Style not dilated at base, 3-branched. Nutlet white to black, ovoid, bony, smooth, hairy or warty, stipitate. x = 5, 7 (aneuploids).

Perennials, tufted or long-rhizomatous with uniseriate culms. Culms with basal nodes, terete to somewhat flattened. Leaves basal, eligulate; sheath with adaxial apex V-shaped; blade 0 to very short, without keeled midrib, profile elliptical. Inflorescence pseudolateral, capitate, of 10-60 sessile spikelets or with 1-6 stalked globose clusters of several sessile spikelets; basal bract erect, appearing as a continuation of culm. Spikelets bisexual (plants functionally dioecious in S. dioecus); glumes several, spirally arranged, emucronate or mucronate. Perianth 0. Stamens 3. Style base persistent; branches 3. Nutlet elliptic to obovate, 3-angled, minutely reticulate.

Perennials, tufted. Culms erect, with aerial nodes. Leaves basal and cauline, ligulate; sheath with adaxial apex truncate; blade linear, flat or setaceous, with or without keeled midrib, profile V-shaped. Inflorescence a reduced or large panicle. Spikelets unisexual or bisexual, florets unisexual; female floret subtended by, and partially or completely enclosed by, modified prophyll (perigynium) together with abaxial rachilla; rachilla sometimes vestigial, frequently carrying exserted male spikelet of 1-6 florets. Perianth 0. Stamens 1-3. Style 3-branched. Nutlet brown, ovate, oblong, elliptic or obovate, 3-angled to somewhat flattened, beaked, smooth.