Vitex is a genus of flowering plants in the sage family Lamiaceae. It has about 250 species.[1] [2] Common names include chaste tree or chastetree, traditionally referring to V. agnus-castus, but often applied to other species, as well.
Species of Vitex are native throughout the tropics and subtropics, with a few species in temperate Eurasia and one in New Zealand.[3] [4]
About 18 species are known in cultivation. V. agnus-castus and Vitex negundo are often grown in temperate climates.[5] About six others are frequently grown in the tropics.[6] Most of the cultivated species serve as ornamentals. Some provide valuable lumber. The flexible limbs of some species are used in basket weaving.[4] Some of the aromatic species are used medicinally[6] [7] or to repel mosquitos.[6]
The genus Vitex was named by Linnaeus in Species Plantarum in 1753.[8] Vitex was the name used by Pliny the Elder for V. agnus-castus. It is derived from the Latin vieo, meaning to weave or to tie up, a reference to the use of V. agnus-castus in basketry.[9]
As a result of phylogenetic studies of DNA sequences, Vitex is one of several genera that were transferred from the Verbenaceae to the Lamiaceae in the 1990s. It is the largest genus in the subfamily Viticoideae of Lamiaceae.[1] Taxon sampling in molecular phylogenetic studies has never been sufficient to test the monophyly of the Viticoideae, but it is generally thought to be an unnatural group.[10] The subfamily is probably diphyletic, with Premna, Gmelina, and Cornutia constituting one clade, and with Vitex, Petitia, Pseudocarpidium, and Teijsmanniodendron constituting the other.[11]
Vitex is a genus of shrubs and trees, from 1.0 to 35 m tall. Some species have whitish bark that is characteristically furrowed. Leaves are opposite, usually compound. The fruit is a drupe.[12]
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.[11]
Pseudocarpidium, Petitia, and Teijsmanniodendron possibly 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.[13]