English: swampweeds
Genus: ± 80 to 100 species.
Clades: Justiciinae.
Region: tropical and subtropical; introduced in United States.
Ecology: troublesome weeds in irrigation and drainage ditches, rice fields.
BotanyHerb; aquatic.
Leaves: homomorphic, simple and entire; or heteromorphic, pinnately divided basal leaves, with feather-like or linear segments, and undivided leaves higher on the stem.
Flowers: corolla white to purple, 5 equal lobes, or 2 lips with an erect, concave upper lip with two lobes, and a lower lip with 3 lobes; Stamens 4, 2 staminodal, lacking pollen, with filaments united into pairs by a membrane; inconspicuous nectar disc.
fruit: with 6 seeds