Tradescantia

Tradescantia (/ˌtrædəˈskæntiə/[4]) is a genus of 75 species of herbaceous perennial wildflowers in the family Commelinaceae, native to the New World from southern Canada to northern Argentina, including the West Indies. Members of the genus are known by the common names wandering Jew and spiderwort.[5] Other names used for various species include spider-lily, cradle-lily, oyster-plant, and flowering inch plant. The common name wandering Jew is controversial for its anti-Semitic origin.[6]

Tradescantia grow 30–60 cm tall (1–2 ft), and are commonly found individually or in clumps in wooded areas and open fields. A number of species are nyctinastic. They were introduced into Europe as ornamental plants in the 17th century and are now grown in many parts of the world. Some species have become naturalized in regions of Europe, Asia, Africa, and Australia, and on some oceanic islands.[3]

The genus’s many species are of interest to cytogenetics because of evolutionary changes in the structure and number of their chromosomes.[7] They have also been used as bioindicators for the detection of environmental mutagens.[8] Some species have become pests to cultivated crops and considered invasive.

Tradescantia are herbaceous perennials and include both climbing and trailing species, reaching 30–60 centimetres (0.98–1.97 ft) in height. The leaves are long, thin and blade-like to lanceolate, from 3–45 cm long (1.2–17.7 in). The flowers can be white, pink, or purple, but are most commonly bright blue, with three petals and six yellow anthers (or rarely, four petals and eight yellow anthers). The sap is mucilaginous and clear.

A number of species are nyctinastic and have flowers that unfold in the morning and close when the sun shines on the flowers in the afternoon but can remain open on cloudy days until evening.

Phylogenetic studies suggest that Tradescantia can be subdivided into as many as twenty distinct sections, as given here and further circumscribed by Burns et al. (2011).[9]

Enlarging the sections from eight to twelve added six further species for a total of 68. Within section Tradescantia, he distinguished the American species (series Virginianae) from the three Mexican series (Tuberosae, Sillamontanae, and Orchidophyllae). “Type” as listed here indicates species typica. Numbering of sections refers to Hunt’s original (1980) system as a cross check to his index. The renumbered sections from 1986 are given in italics, e.g. (1)(5).[a][b]