Verbena brasiliensis

Verbena brasiliensis, the Brazilian verbena or Brazilian vervain, is a flowering plant species from the vervain family (Verbenaceae). It is native to parts of South America, namely Brazil, but has spread its range in recent times and has occasionally become an invasive weed. It is an annual plant with purple flowers, and it has been introduced outside of its native range as an ornamental plant, and is now largely considered an invasive weed in these regions. In the past, several botanists have mistakenly applied the scientific name of the purpletop vervain, V. bonariensis, to this species. As a consequence, the common names "Brazilian verbena" and "Brazilian vervain" are sometimes erroneously applied to the purpletop vervain....read more on Wikipedia.