Description

Key Characters:

Growth Form: Submerged, aquatic, rootless perennial herbs, without secondary growth.

Stems: Stems branched.

Roots:

Leaves: Leaves simple (highly dissected). Leaves in whorls of 3–12 per node. Blades dichotomously dissected into slender segments. Base sessile. Margins serrulate. Petioles absent. Stipules absent.

Flowers: Flowers minute and inconspicuous, axillary, staminate and pistillate flowers usually solitary at different nodes, often the staminate flowers above the pistillate ones. Flowers unisexual (and the plants monoecious); Hydrogamous (pollination under water). Calyx of 8–15 linear, bract-like segments, connate at base. Corolla (petals) absent. Stamens (5–)10–20(–27), distinct, spirally arranged on the flat receptacle, not clearly differentiated into filament and anther. Ovary superior, consisting of a single carpel tapering; ovule 1, pendulous, orthotropous; style terminal; stigma decurrent.

Fruit: Achenes. Seeds with thin seed coat; endosperm absent.

Ploidy:

Habitat:

Elevation Range: