Persicaria maculosa

An annual herb native from temperate Eurasia to Indochina and from Macaronesia to northern Africa, it belongs to the Polygonaceae family. It has become extensively naturalized beyond Eurasia and is now widespread in both hemispheres. It grows in moist disturbed ground, with erect or spreading stems that are often reddish. The narrow leaves usually bear a dark central blotch. A fringed, tubular sheath surrounds the stem at each leaf base. Dense, spike-like clusters contain small pink or occasionally white flowers. The fruits are shiny, brownish black nuts, either flattened or three-sided. Photographed in Colombia.