For the identification of insects and other fauna and flora of South Africa.

Sunday, July 21, 2013

Coastal Silveroak (Brachylaena discolor)

Family Asteraceae
Description
Brachylaena discolor forms a dense, wide, spreading, single or multi-stemmed tree that branches low down to form an irregular v-shaped canopy. The trunk reaches 45 cm in diameter and is covered with light brown fibrous bark. The trunk is divided into several large branches that tend to grow upwards and then horizontally to form bows. In the garden this tree grows to a height of 4-10 m but can reach up to 27 m in a forest.

This fast growing evergreen has a silvery-blue appearance from a distance so that it stands out amongst other vegetation. The attractive and unusual foliage characterizes this tree. The leaves are simple, large (5-11 cm long x 1,3 cm wide), leathery and glossy dark green above and covered with a silvery-white felt of dense hairs below. The margin is distinctly toothed in young leaves and irregularly toothed in older leaves. The leaves are elliptic with rounded tip and narrow base and are spirally arranged towards the ends of branchlets and twigs. The movement of the wind through the tree exposes the lovely silver undersides of the leaves.

Masses of nectar rich creamy-white flowers are grouped in 7 to 50 flowered heads, and the heads are grouped together in large terminal panicles. These thistle-like flowers grow at the ends of branchlets. The male and female flowers are borne on separate trees. Flowering season is during winter-spring (July to September), and when in flower, the entire tree is covered in flowers. Being nectar rich they attract bees, birds and other insects that come to feed on the nectar or on the insects attracted by the nectar.

The seed is a small nutlet in a brown capsule that is tipped with yellowish, paintbrush-like hairs, and is ripe in summer (November to January).

Brachylaena discolor is a very decorative shrub or small to medium-sized tree, an excellent hedge plant and is particularly useful for stabilising dunes.

Distribution

Brachylaena discolor occurs in coastal woodland, bush and on the margins of evergreen forest from the Eastern Cape to Mozambique. It is also very common and easy to find in the dune forests of the coast, where it grow in groups, and in the low-lying, sand and scarp forests of the coast, along rivers and in woodland of the bushveld-savannah. Its natural inclination is to form a dense bushy shrub.

Medicinal and cultural uses

The wood of Brachylaena discolor is yellow, durable and very strong and is used in the manufacture of boats at it lasts well in water, as well as for fence posts, huts, axles, spokes, implement handles, knobkerries, and long straight branches used to construct roofs of huts. Suitable branches also make excellent fishing rods, and fire shades are also made from this wood. The wood is extensively used for carving purposes by Kenyans, where it is regarded as the best wood after African black ebony. The leaves are very bitter and unpalatable and are occasionally browsed by nyala, bushbuck, red and blue duiker. Both Africans and European settlers used the leaves for medicinal purposes to treat kidney conditions. The leaves were used by country folk to make remedy for diabetes. The Zulu people used an infusion of the roots as an enema to stop bleeding of the stomach and an infusion of the leaves as a tonic to treat intestinal parasites and for chest pain. The ashes of the tree were used by early settlers to provide the alkali needed in soap making. The roots and stems were used by Zulu diviners to communicate with their ancestors. Brachylaena discolor is an excellent bee tree and is popular with beekeepers as it makes good honey.