Region: East Asia, southern China, India, Sri Lanka, Myanmar, Thailand, Cambodia, Laos, Vietnam, Malaysia, Indonesia.
Habitat: wet topical and subtropical; in ditches, pools, rice fields, marshy places, lowland; still or stagnant water in pools, lakes, ditches.
Use: flowers for red dye for the fingernails; organic water farming.
BotanyHerb; erect; many-branched; semi-aquatic, lower parts of the stem submerged; perennial; 1 meter tall.
Flowers: united petals.
Pollination: by insects.
Fruit: hairy.