Genus VitexL. | ||
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Vitex /ˈvaɪtɛks/ is a genus of flowering plants in the family Lamiaceae. It has about 250 species. Common names include "chastetree", traditionally referring to V. agnus-castus but often applied to other species as well.
Contents
Species of Vitex are native throughout the tropics and subtropics, with a few species in temperate Eurasia.
About 18 species are known in cultivation. Vitex agnus-castus and Vitex negundo are often grown in temperate climates. About six others are frequently grown in the tropics. Most of the cultivated species serve as ornamentals. Some provide valuable lumber. The flexible limbs of some species are used in basket weaving. Some of the aromatic species are used medicinally or to repel mosquitos.
The genus Vitex was named by Linnaeus in Species Plantarum in 1753. Vitex was the name used by Pliny the Elder for Vitex agnus-castus. It is derived from the Latin vieo, meaning to weave or to tie up, a reference to the use of Vitex agnus-castus in basketry.
Vitex is one of several genera that was transferred from Verbenaceae to Lamiaceae in the 1990s as a result of phylogenetic studies of DNA sequences. It is the largest genus in the subfamily Viticoideae of Lamiaceae. Taxon sampling in molecular phylogenetic studies has never been sufficient to test the monophyly of Viticoideae, but it is generally thought to be an unnatural group. The subfamily is probably diphyletic, with Premna, Gmelina, and Cornutia constituting one clade, and with Vitex, Petitia, Pseudocarpidium, and Teijsmanniodendron constituting the other.
Description
Vitex is a genus of shrubs and trees, from 1 to 35m tall. Some species have whitish bark that is characteristically furrowed. Leaves are opposite, usually compound. The fruit is a drupe.
Circumscription
In 2009, a molecular phylogenetic study showed that three small genera, Paravitex, Viticipremna, and Tsoongia are embedded in Vitex. These three genera were duly sunk into synonymy with Vitex.
It is possible that Pseudocarpidium, Petitia, and Teijsmanniodendron are nested within Vitex. Sampling in the 2009 study was not sufficient to determine the phylogenetic position of these genera. The relationships of Teijsmanniodendron to these genera was not discussed in a revision of Teijsmanniodendron in 2009.