fresh water scapigerous herbs, stems short or elongated, stoloniferous. Leaves
radical or cauline, linear or lanceolate, prominently veined, sheathed at base.
Spathe sessile or pedunculate, tubular, 2-toothed. Flowers bisexual or unisexual. Male flowers :
several, sepals 3, linear, petals 3, longer, stamens 3-9, anthers narrow,
pistillodes 3. Female flowers : solitary, perianth as in male, staminodes
absent or minute. Ovary linear, beaked, styles 3, ovules numerous. Fruit a
capsule, enclosed in spathe. Seeds
smooth or with rows of elongated spines.