Pipewort Family. Bog or aquatic herbs, perennial or perhaps sometimes annual, with fibrous knotted or spongy roots, tufted grass-like basal leaves, and monoecious (androgynous) occasionally dioecious small flowers, in terminal solitary heads, on long slender scapes. Head of flowers involucrate by bracts, each flower borne in the axil of a scarious scale. Perianth of 2 series of segments, rarely of one series. Stamens in staminate flowers as many or twice as many as the sepals. Ovary 2-3-celled. Ovules 2 or 3. Fruit a 2-3-celled, 2-3-seeded capsule, loculicidally dehiscent. Seeds pendulous, orthotropous; endosperm farinaceous.

Nine genera and about 560 species, widely distributed in warm and tropical regions, a few extending into the temperate zones. The family is most abundantly represented in South America. Perianth of 2 series of segments; sepals and petals 2 or 3; stamens distinct; anthers 2-celled.

Stamens twice as many as the inner perianth-segments (petals).



Stamens as many as the inner perianth-segments.



Perianth simple, of 3 sepals; stamens 3, monadelphous below; anthers 1-celled.