Acmella repens aka Oppositeleaf Spotflower

Acmella repens is a perennial herb in the aster family, Asteraceae. Kew also records its form as a perennial or subshrub. Its native range spans the central and southeastern United States. It extends through Central America to Venezuela and Paraguay. The plant is also native to Cuba. Kew places it in a subtropical climate. Useful Tropical Plants lists Texas, Florida, and North Carolina within its range.

The stems lie low or trail across the ground. They form roots at their nodes, which can produce new plants. This gives the plant a creeping form rather than an upright one. The source gives its usual height as about 1.6 feet [0.5 metres]. It also lists a separate height of 1.3 feet [0.4 metres]. Some plants reach 3.9 feet [1.2 metres], above the usual size. These figures describe the plant, not a tested garden range. The evidence gives no mature spread or detailed leaf description.

This species grows in damp ground and places that flood. Its habitats include swamps and the edges of streams and lagoons. It also grows beside canals and in flooded fields. Records reach about 9,500 feet [2,900 metres] above sea level. It can occur as a weed in farmed land. That record does not establish that it is invasive. Its habitat points to a preference for moist to wet soil. The source gives no growing instructions, frost limits, or light needs. It lists seed as a means of propagation.

People gather wild plants for local medicinal use. Leaves and flower heads feature in traditional care for mouth pain. People use infusions as rinses for toothache and mouth wounds. They also chew the leaves and flowers for dental care. The plant contains spilanthol, a compound reported to have numbing effects. Other recorded uses include preparations for stomach pain and diarrhoea. These are reports of traditional use, not proof of treatment benefits.

Useful Tropical Plants records no known food uses or hazards. A lack of recorded hazards does not prove safety. Medicinal use also does not establish that the plant is edible. The supplied evidence gives no flower colour, bloom season, or fruit details. It names no pests or diseases and documents no landscape use.