Description

Key Characters:

Growth Form: Aquatic or terrestrial annual or perennial herbs, sometimes small shrubs, glabrous or pubescent with simple hairs.

Stems: Stems prostrate to ascending or erect, often rooting at the lower nodes.

Roots:

Leaves: Leaves simple. Opposite, alternate, or whorled. Blades diverse in shape and size. Margins entire, toothed, or deeply dissected. Petiolate or sessile. Stipules absent.

Flowers: Flowers in indeterminate or determinate spikes, racemes, or panicles, sometimes solitary and axillary, each flower often subtended by persistent or deciduous bracteoles. Flowers usually small, bisexual (perfect) or unisexual (and then plants monoecious or dioecious), actinomorphic. Calyx of (2–)4 sepals. Petals usually as many as sepals, deciduous with the stamens. Stamens as many or twice as many as sepals; anthers tetrathecal, opening by slits. Ovary inferior, (2–)4-celled; ovules 1–2 per cell, but only 1 maturing, anatropous, pendulous from apex; styles as many as sepals, rarely half as many, feathery.

Fruit: Fruit small; nutlike; usually ovoid; variously ornamented with wings; ribs; or tubercles; the sepals persistent on the fruit; erect or reflexed. Seeds 1–4; endosperm copious; fleshy and oily.

Ploidy:

Habitat:

Elevation Range: