Pontederia vaginalis N. L. Burman, Fl. Indica 80. 1768; Boottia mairei H. Léveillé; Monochoria linearis (Hasskarl) Miquel; M. ovata Kunth; M. vaginalis var. pauciflora (Blume) Merrill; M. vaginalis var. plantaginea (Roxburgh) Solms; P. linearis Hasskarl; P. ovata Hooker & Arnott (1837), not Linnaeus (1753); P. pauciflora Blume; P. plantaginea Roxburgh.

Herbs aquatic. Stems erect or obliquely so. Radical leaves with broad sheath; petiole 3--50 cm; leaf blade narrowly cordate, broadly or narrowly ovate, or lanceolate, 2--21 × 0.8--10 cm, apex acute to acuminate. Flowering stems 12--35 cm. Inflorescences soon reflexed after anthesis, 3--8(--12)-flowered; peduncle 1--3 cm, base bracteate; bract lanceolate. Flowers pedicellate. Perianth segments purplish, ovate-lanceolate to oblong, 0.8--1.5 cm. Larger stamen: filament appendaged; anther 1.8--4 mm. Smaller stamens: filaments filiform; anthers 1.5--3 mm. Capsule ovoid to ellipsoid, 0.7--1 cm. Seeds ellipsoid, ca. 1 mm; wings 8--12. Fl. Aug--Sep, fr. Sep--Oct.

The stems and leaves are used as a vegetable.

Rice fields, ditches, ponds, swamps; near sea level to 1500 m. Throughout China [Bhutan, Cambodia, India, Indonesia, Japan, Korea, Laos, Malaysia, Myanmar, Nepal, Pakistan, Philippines, Russia (Siberia), Sri Lanka, Thailand, Vietnam; Africa, Australia].