Angiosperms (Flowering Plants) • Earth.com

Brazilian verbena

(Verbena brasiliensis)

galery
en

Description

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. 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 reproduces sexually via seed production. Verbena brasiliensis is often confused with Verbena litoralis because they are found in similar habitats. However, their inflorescences are different enough to easily separate the species. Verbena brasiliensis has short and compact spikes in open cymes, whereas Verbena litoralis has longer spikes that are arranged in paniculate cymes.

Taxonomic tree:

Domain:
Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Order:Lamiales
Family:Verbenaceae
Genus:Verbena
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