Pistia

Acaulescent, free-floating, stoloniferous, freshwater herb, with many feathery fibrous roots. Leaves forming a rosette, obovate to obdeltoid, broadest above, densely pilose, green, with several +/- parallel veins arising at base. Inflorescence small, hidden among leaf bases. Spathe convolute at base, apical part +/- erect, expanded, acute-acuminate, white. Spadix in three parts, lower pistillate and naked portions adnate to spathe, upper staminate portion free. Flowers without perianth segments. Male flowers 2-8, each consisting of 2 stamens forming a synandrium, encircled by a cupular annulus and beneath it a laterally attached semicircular lobe; anthers opening by short oblique slits. Female flower solitary; ovary unilocular, oblique; ovules many, orthotropous, on a basal placenta; style obliquely erect, stigma subspherical. Fruit a berry, globose to ellipsoid, with a thin pericarp, many-seeded. Seeds subovoid, truncate at both ends, hard, verrucose; with abundant endosperm. x= 14.