Pontederiaceae
Herbs, annual or perennial, aquatic, rooted in mud or free-floating. Stems of 2 types, vegetative and flowering; vegetative stems indeterminate, bearing many leaves, glabrous; flowering stems determinate, usually emersed, bearing single leaf, spathe, and terminal inflorescence. Leaves of 2 types, sessile and petiolate; stipule marcescent, apex truncate, associated with petiolate leaves only; sessile leaves submersed or rarely emersed, forming basal rosette or alternate on elongate stem, blade linear to occasionally oblanceolate, base sheathing, margins entire; petiolate leaves floating or emersed, blade cordate, reniform, or ovate. Inflorescences paniculate, spicate, umbellate, or 1-flowered; spathes bractlike, folded or clasping, commonly with acute to caudate extension. Flowers sessile, 3-merous; perianth with tepals connate proximally, yellow, blue, mauve, or white, tube tubular or funnelform, limb 6-lobed; stamens 3 or 6, adnate to perianth; pistils 3-locular, 1 or 3 developing to maturity; placentation parietal or basal; ovules 1–many. Fruits capsular or utriculate. Seeds smooth or with longitudinal wings.
Distribution
{{#Distribution Maps: family
|Nearly worldwide;primarily of tropical and subtropical regions.
|
| }} Nearly worldwide, primarily of tropical and subtropical regions.
Discussion
Genera 6, species ca. 30 (4 genera, 11 species in the flora; 2 genera, 3 species introduced).
Selected References
Lower Taxa
Key
| 1 | Inflorescences commonly with more than 50 flowers; fruits utriculate, 1-seeded | Pontederia |
| 1 | Inflorescences with fewer than 30 flowers; fruits capsular, 10–200-seeded. | > 2 |
| 2 | Tepals connate only basally | Monochoria |
| 2 | Tepals connate 1/2 or more of their length. | > 3 |
| 3 | Petiolate leaf blade coriaceous; perianth limb lobes ovate, longer than 2 cm; stamens 6 | Eichhornia |
| 3 | Petiolate leaf blade membranous or absent; perianth limb lobes linear to oblanceolate, shorter than 2 cm; stamens 3 | Heteranthera |
