Perennial rhizomatous herb of freshwater wetlands, with sympodial growth. Rhizome bearing tufts of leaves surrounded at the base by membranous tubular cataphylls that split during growth. Leaves linear, triangular to elliptic in transverse section, with inverted vascular bundles (with the xylem facing outwards). Scape leafless, with inverted vascular bundles. Inflorescence a bractless spike. Flowers (except in the inflorescence tip where the flower ground-plan is variable): tepals 2 in transversal-abaxial positions; stamens 6 in two trimerous whorls with sessile anthers (without filaments), anthers tetrasporangiate, dithecal; each of the anther thecae with a short thick apical appendage and a deep dorsal groove, dehiscing in the groove; carpels 4, in median and transversal positions; ovules orthotropous, the nucellus coenocytic. Fruits indehiscent, the carpels each with 2 recurved lateral wings and a short stylar beak.
Home