Brazilian Vervain

Verbena brasiliensis is an erect herb with serrate leaves and overlapping fruits. Its flowers are usually purplish in color. This plant exhibits a terminal inflorescence, with flowers grouped closely together. It grows as a forb, herb, or subshrub. The stems are roughly 1 meter tall and mostly glabrous below and scabrous-pubescent above. While the lower branches exhibit opposite arrangement, the upper branches grow in an irregular formation. The stem is mildly indented at the nodes. The leaves are membranaceous and have connate bases and have a mildly pubescent underside. The calyx of the flowers is about 3 mm long, five-lobed, and tubular. Nerves in the calyx extend beyond the lobes to form teeth. The posterior nerve is always shortest. The corolla is formed of fused petals that spread open at the end, and is just a little longer than the calyx. The flower possesses reproductive organs of both sexes. The ovary is superior and bicarpellary. The fruit is a schizocarp, a type of dry fruit that splits when mature. It is encased in the calyx, and released by the shortest posterior nerve of the calyx. The nutlets are triangular in cross section and are about 2 mm long each. Four nutlets are generally produced by each fruit, with two per each carpel. …

Verbena brasiliensis is currently found in many regions, including North America, Oceania, Africa, Asia, and Europe, where it is largely considered invasive. Verbena brasiliensis is native in South America, specifically, Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Paraguay, Peru, and Uruguay. There, it grows in dry conditions on agricultural fields and is considered a weed. In locations where it is invasive, it grows well in man-made areas or riverine environments. In the United States, it is found mostly in grasslands, rangelands, riparian zones, urban areas, and wetlands. The US states where the plant occurs include Oregon, California, Texas, Oklahoma, Missouri, Arkansas, Louisiana, Kentucky, Tennessee, Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina, Virginia, and Hawaii.

Verbena brasiliensis has been used as a garden and ornamental plant. It has been cultivated within and largely outside of its native range for aesthetic uses.