Description

Key Characters:

Growth Form: Fronds free–floating on or just beneath water surface, solitary or cohering in colonies.

Stems: Stems flattened leaflike, usually greenish or purplish to reddish on lower surface, obovate to orbicular or greatly elongated.

Roots: Each plant with a single peltately attached root.

Leaves: Leaves absent. Alternate. Stipules absent.

Flowers: Flowers borne in a pouch, 2 staminate and 1 pistillate, enclosed in a membranous sheath in a marginal cleft of the frond, opening along the side or nearly closed. Flowers unisexual, 1(--2) per frond, surrounded by small utricular, membranous scale. Calyx absent. Corolla (petals) absent. Stamens 2, 4-locular. Ovary superior; ovules 1–3.

Fruit: Utricles unwinged. Seeds 1–6; usually ribbed and with minute transverse striations.

Ploidy: 2n = 20; 42; 44

Habitat:

Elevation Range: