Tradescantia fluminensis

river spiderwort

 

Tradescantia fluminensis

Vell. 1829

pronounced: trad-ess-KAN-tee-uh flew-min-EN-siss

(Commelinaceae — the wandering Jew family)

 

common names: river spiderwort, creeping Christian, wandering Jew

Tradescantia is named for John Tradescant, 17th century botanist and gardener; fluminensis is from the Latin flumen, a river.

This is a native of south-eastern Brazil, Argentina and Uruguay. It is now widely naturalized in much of the world, including Australia, where it is found in eastern Queensland, eastern NSW, Victoria, Tasmania and the south of Western Australia. It is a weed of forests, forest margins, urban bushland, open woodlands, riparian vegetation, roadsides, ditches, waste areas, disturbed sites and gardens. It prefers damp and shaded areas in temperate and sub-tropical regions, but will also flourish in more open habitats and tropical regions. It is one of several plants known by the common name of Wandering Jew.

It is a perennial herbaceous plant with trailing or creeping stems up to 4 m long. The stems are semi-succulent, branched, and produce adventitious roots at the nodes. It can form a very dense mat of vegetation.

The shiny leaves have dark green upper surfaces, with undersides that are often purplish. The leaves are alternate, and have sheathed bases around the creeping stems. The leaves themselves are also semi-succulent, and measure 3 – 6.5 cm in length by 1 – 3 cm in width. They may be broadly lanceolate, ovate, or oblong, with entire margins and acute apices. The leaf sheathes can be either pubescent or glabrous, while the leaf blades are glabrous or may occasionally have some cilia along their margins.

The flowers are borne in small clusters near the tips of the branches. Each cluster has 2 small leafy bracts at the base, and the individual flowers are borne on pedicels 1 – 1.5 cm long. They have 3 white petals (7 – 10 mm long) with acute apices, 3 greenish sepals, and 6 small yellow stamens.

The fruits are small capsules, with 3 chambers. Although black pitted seeds are produced in some countries, the species is not known to produce viable seeds in Australia, and reproduces vegetatively.

Fragments of the stems easily break off, and may be dispersed by water, vehicles, machinery, or in dumped garden waste. This is a significant environmental weed with serious invasive qualities. These result from a combination of attributes. Underneath forest tree cover, due to its remarkable shade tolerance, it can form a dense mat up to 30 cm deep, or even more. This smothers ground-level plants and prevents the natural regeneration of taller species, and, if left unchecked, can eventually lead to the destruction of native forests.

 

Photographed in Picnic Bay 2018
Page last updated 22nd April 2019