Description

Key Characters:

Growth Form: Glabrous perennial herbs of wet or swampy habitats, with extensive starchy creeping rhizomes, often forming large dense colonies.

Stems: Stems erect, unbranched, terminating in an inflorescence.

Roots: Fibrous root system.

Leaves: Leaves simple. Alternate, distichous and erect. Blades linear, nearly all basal, blades flattened, usually spongy in texture, with longitudinal partitions connecting the upper and lower surfaces, and numerous cross partitions connecting the longitudinal ones. Margins entire. Veins parallel. Sheathing the stem. Stipules absent.

Flowers: Flowers numerous in dense, cylindrical, complex spikes, staminate spikes above pistillate ones, the spikes contiguous or separated, most of the flowers axillary to short bristle-like bracts. Flowers unisexual; Staminate flowers with modified perianth of 0–3(–8) slender capillary bristles or scales, stamens (1–)3(–8), filaments short, distinct or connate nearly throughout their length, anthers dithecal, with a broad connective prolonged beyond the pollen sacs; pistillate flowers sometimes sterile with an abortive ovary, these intermixed with fertile flowers, all with modified perianth of numerous slender, capillary bristles, these sometimes somewhat thickened apically, or narrow scales in 1–4 irregular whorls, some of the members occasionally connate into small groups and usually some of them adnate to lower part of gynophore. Calyx (sepals) absent. Corolla (petals) absent. Stamens 1–3 in staminate flowers, absent in pistillate flowers. Ovary superior, 1-carpellate, elevated on a gynophore that elongates in fruit to form a slender stipe; ovule 1, pendulous from near apex of carpel, apotropous or anatropous; style terminal, elongating and persistent in fruit; stigma linear to spatulate, dry.

Fruit: Fruit small; dry; tardily dehiscent; wind–dispersed. Seeds with a slender; cylindrical embryo surrounded by copious mealy endosperm and thin perisperm.

Ploidy:

Habitat: Aquatic.

Elevation Range: