Leucosidea

Leucosidea sericea, commonly known as ouhout in Afrikaans, is an evergreen tree or large shrub that grows in the Afromontane regions of southern Africa. It is the sole species in the genus Leucosidea. The English name "oldwood" is simply a direct translation of the Afrikaans words "ouhout" or "oudehout", meaning the same thing. This name may reflect the fact that the wood burns slowly as if old and rotting, but the gnarled twisted trunks reinforce this impression.[1][2]

Oldwood
The inflorescence, a terminal spike with small yellowish-green flowers
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Rosales
Family: Rosaceae
Subfamily: Rosoideae
Tribe: Sanguisorbeae
Subtribe: Agrimoniinae
Genus: Leucosidea
Eckl. & Zeyh.
Species:
L. sericea
Binomial name
Leucosidea sericea
Foliage and flower bracts

The genus name Leucosidea is a form of the Greek word λευκός (leukos), meaning "shining white", although in botany the root is more often used less specifically to indicate something of a generally white or gray appearance.[3] The second or specific name sericea means "silky" and comes from σηρικός (serikos), which means both "silky" and "from the land of silk"; it refers to the silky hairs that cover the new buds and young leaves of the tree.[4]

Taxonomy

Leucosidea sericea is a member of the Rosaceae, also known as the rose family. Although this family is very large and economically important worldwide, it is poorly represented in Africa generally and in southern Africa in particular.

Description

The ouhout is often a straggly shrub or a dense, small, evergreen tree, which grows up to 7 metres tall to 5 metres wide. It is single or multi-stemmed and branches low down. The bark is rough, reddish brown in colour and flakes off to reveal a smooth light brown under-bark. The leaves are alternately arranged, compound and covered with silky, silver hairs. Each leaf possesses 3 to 4 pairs of leaflets. The veins on the leaves are deeply sunken on the upper surface and protrude on the lower surface. The leaves are a dark green colour above and a lighter green colour below. The margins of the leaflets are deeply serrated. When the leaves are crushed they have a strong herb-like smell.

The flowers are greenish-yellow in colour, star-shaped, and grow in spikes at the ends of young shoots in spring (August to September). The fruits are nut-like and about 3 mm in diameter (December to January).

The flowers and young shoots of this plant are browsed by cattle and goats in spring. The ouhout produces nectar which is probably utilised by bees and other insects.

Distribution and habitat

Leucosidea sericea can be found above an elevation of 1,000 metres (3,300 ft) in the highlands of South Africa (in the Eastern Cape, western KwaZulu-Natal, eastern Free State,the North West Province, Gauteng, Mpumalanga, and Limpopo), as well as in Lesotho and, rarely, in Swaziland and Zimbabwe. It forms dense thickets in abused areas and can, therefore, become a problem plant on farm lands. Its presence is an indication of overgrazing or poor veld management.

Uses

Apparently in mountainous areas where the ouhout occurs near streams it is an indication that they are suitable for being stocked with trout. Zulu people use a paste made from the crushed leaves of L. sericea for treating ophthalmia (an eye ailment). The tree is used by the local people as a charm to protect the inhabitants of homesteads.

It has been reported that the leaves of Leucosidea sericea are used medicinally by some indigenous South African people as a vermifuge and astringent.[5] A study showed that "the plant has antimicrobial activity against Staphylococcus aureus, Bacillus subtilis and Candida albicans."

Leucosidea sericea is usually found growing in dense thickets at altitudes above 1,000 metres. It can be found growing in open grassland, along river banks and on wooded, rocky ridges. It is usually found growing in damp conditions, on deep, sandy or clayey and often rocky soil.

The wood weighs 38 pounds per cubic foot (0.61 g/cm3), and is used mainly for fenceposts and fuel.

References
  1. Jacobson, Arthur Lee (June 2008). "Plant of the Month: South African Oldwood Leucosidea sericea Eckl. & Zeyh. ROSACEÆ; Rose Family". arthurleej.com. Retrieved 9 October 2019.
  2. K.C. Palgrave's (1977), Trees of South Africa
  3. "3022. Leukos". BibleSuite. Biblos. p. 3022. Retrieved December 29, 2012.
  4. "4596. Serikos". BibleSuite. Biblos. p. 4596. Retrieved December 29, 2012.
  5. "Isolation of an anthelmintic compound from Leucosidea sericea". South African Journal of Botany. 70 (4): 509–511. 2004.
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