Tradescantia

 ( Commelinaceae Genera ) 

A number of species have flowers that last for only a day, opening in the morning and closing by the evening.

Plants of the genus are called by many , varying by region and country. The name "inchplant" is thought to describe the plant's fast growth, or the fact that leaves are an inch apart on the stem. "Spiderwort" refers to the sap which dries into web-like threads when a stem is cut. The name "dayflower", shared with other members of the Commelinaceae family, refers to the flowers which open and close within a single day.

The controversial name "wandering Jew" originates from the Christian myth of the Wandering Jew, condemned to wander the earth for taunting Jesus on the way to his crucifixion.Anderson, George K. The Legend of the Wandering Jew. Providence: Brown University Press, 1965. xi, 489 p.; In recent years there have been efforts to stop using this and other potentially offensive common names, in favour of alternatives such as "wandering dude" or "wandering willie".

In Spanish, Tradescantia plants are sometimes referred to as flor de Santa Lucía (Saint Lucy's flower), in reference to the Saint's reputation as the patron saint of sight, and the use of the juice of the plant as eye drops to relieve congestion.

A recent study by Pellegrini (2017) proposed a new classification based on recent morphological research, dividing the genus into five subgenera. As of December 2023, The Royal Botanic Gardens, Kew recognises 86 species.

• Tradescantia petiolaris M.E.Jones

• Tradescantia × andersoniana W.Ludw. & Rohweder The name was published with no description, so is not a valid botanical name; the taxon is now treated as a cultivar group.
• Callisia navicularis (Ortgies) D.R.Hunt (as T. navicularis Ortgies)
• Callisia warszewicziana (Kunth & C.D.Bouché) D.R.Hunt (as T. warszewicziana Kunth & C.D.Bouché)
• Gibasis geniculata (Jacq.) Rohweder (as T. geniculata Jacq.)
• Gibasis karwinskyana (Schult. & Schult.f.) Rohweder (as T. karwinskyana Schult. & Schult.f.)
• Gibasis pellucida (M.Martens & Galeotti) D.R.Hunt (as T. pellucida M.Martens & Galeotti)
• Siderasis fuscata (Lodd. et al.) H.E.Moore (as T. fuscata Lodd. et al.)
• Tinantia anomala (Torr.) C.B.Clarke (as T. anomala Torr.)
• Tripogandra diuretica (Mart.) Handlos (as T. diuretica Mart.)
• Elasis hirsuta (Kunth) D.R.Hunt (as T. hirsuta)

The natural range of the genus as a whole spans nearly the entire length and width of mainland North America, from Canada through Mexico and Central America, and thrives in a great diversity of temperate and tropical habitats. It is frequently found in thinly wooded deciduous forests, plains, prairies, and healthy fields, often alongside other native wildflowers.

Most cold-hardy garden plants belong to the Andersoniana Group (often referred to with the invalid name Tradescantia × andersoniana). This is a group of interspecific hybrids developed from Tradescantia virginiana, T. ohiensis, and T. subaspera, which have overlapping ranges within continental North America. These plants are clump-forming herbaceous perennials, with individual cultivars mainly differing in flower colour.

A wide range of tender tropical species are cultivated as houseplants or outdoor annuals in temperate locations, including Tradescantia zebrina, T. fluminensis, T. spathacea, T. sillamontana, and T. pallida. They are typically grown for their foliage, and many have colourful variegated patterns of silver, purple, green, pink, and gold.

• T. (Andersoniana Group) 'Concord Grape'
• T. cerinthoides 'Nanouk'
• T. cerinthoides 'Variegata'
• T. fluminensis 'Aurea'
• T. fluminensis 'Quicksilver'
• T. pallida 'Purpurea'
• T. spathacea 'Rainbow'
• T. zebrina 'Purpusii'
• T. zebrina 'Quadricolor'

The International Society for Horticultural Science appointed Tradescantia Hub as an International Cultivar Registration Authority (ICRA) for Tradescantia in 2022. As an ICR authority, the Hub is responsible for recording and maintaining a checklist of the correct names for all cultivars in the genus.