Thursday, 8 December 2016

MELBOURNE STREET TREES 176 - TAMARISK

The genus Tamarix (tamarisk, salt cedar) is composed of about 50–60 species of flowering plants in the family Tamaricaceae, native to drier areas of Eurasia and Africa. The generic name originated in Latin and may have referred to the Tamaris River in Hispania Tarraconensis (Spain).

They are evergreen or deciduous shrubs or trees growing to 1–18 m in height and forming dense thickets. The largest, Tamarix aphylla, is an evergreen tree that can grow to 18 m tall. They usually grow on saline soils, tolerating up to 15,000 ppm soluble salt and can also tolerate alkaline conditions. Tamarisks are characterised by slender branches and grey-green foliage. The bark of young branches is smooth and reddish brown. As the plants age, the bark becomes bluish-purple, ridged and furrowed. The leaves are scale-like, 1–2 mm long, and overlap each other along the stem. They are often encrusted with salt secretions. The pink to white flowers appear in dense masses on 5–10 cm long spikes at branch tips from March to September, though some species (e.g. T. aphylla) tend to flower during the winter.

Illustrated here is a hybrid of the species Tamarix chinensis.  Tamarix chinensis is a species of tamarisk known by the common names five-stamen tamarisk and Chinese tamarisk or saltcedar. It is native to China and Korea, and it is known in many other parts of the world as an introduced species and sometimes an invasive noxious weed. It easily inhabits moist habitat with saline soils. It may grow as a tree with a single trunk or as a shrub with several spreading erect branches reaching 6 metres or more in maximum height. It has been known to reach 12 metres.

It has reddish, brown, or black bark. The small, multibranched twigs are covered in small lance-shaped, scale-like leaves which are no more than about 3 mm long. The inflorescence is a dense raceme of flowers a few cm long. Each fragrant flower has five petals which are usually pink but range from white to red. This tamarisk can hybridise with Tamarix parvifloraT. ramosissima may be treated in synonymy or as a separate species.

It has become an aggressive invader of wildlands in the southwestern United States, where it was once planted as an ornamental plant. It reproduces vegetatively from its roots and also from its foliage if it happens to be covered by soil, as in sediment-rich flooding. It also reproduces by its seed, which are tiny and tufted with hairs, easily dispersing on the wind. Despite its reputation as a noxious weed, the tree can be useful for wood, in honey production, and as a nesting site for various birds. In its native habitat in China the plant forms thickets that act as useful barriers on the margins of waterways, including saline ocean shores.

This post is part of the Floral Friday Fotos meme.







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