Herbs annual [perennial], ter­restrial, amphibious, or aquatic. Stems erect or decumbent, un­branched or branched. Leaves opposite, monomorphic; blade obovate to oblong or subspatulate [ovate, lanceolate, linear], 4–20 × 3–8 mm, base attenuate to obtuse, margins white-cartilaginous, especially prominent when dry. Inflorescences terminal or axillary racemes, short axillary spikes, or solitary flowers. Floral tube 1.5–2.5 × 1–1.5 mm; epicalyx segments absent; sepal margins cartilaginous; petals persistent, 4, pink, linear to narrowly ovate, less than 1/2 length of sepals; stamens inserted about mid level in floral tube; style slender; stigma capitate. Capsules ca. 2 × 1.5 mm, 2-valved. 2n = 32 (China, Japan).

Phenology: Flowering late spring–summer.
Habitat: Rice fields, irriga­tion ditches.
Elevation: 50–100 m.

Distribution

• Generated Map
• Legacy Map

Introduced; Calif., La., se Asia (to Japan), introduced also in Europe, Africa.

Discussion

Rotala indica probably was introduced into the flora area as a contaminant of imported rice seed stock. It frequently occurs in rice fields together with the native R. ramosior and/or Ammannia coccinea.

Selected References

None.

Lower Taxa

None.