General Info

The Tree may reach 8m high and 0,6m wide. Bark – reddish brown, to brown and smooth. The thin, ovate to elliptic Leaves are simple. Stipules fall early. Sweetly scented, white Flowers with 3-4 sepals and up to 13 whorled petals. Fruit is globose, up to 6cm wide with a hard woody shell.

Description

Tree

Oncoba spinosa.

RSA Tree No. 492.

Family: Salicaceae: (the willow family has recently been expanded and includes 55 genera and 1 000+ species. Trees may be deciduous or evergreen. Leaves are simple and they and bark often contain Salicin (a bitter alcoholic glucoside related to asprin, found in willow bark and leaves of some Salicaceae. It can function as an anti – inflammatory. It may cause a skin allergy). Flowers are genetically hermaphroditic, in catkins and usually lacking a normal perianth. A bract subtends each flower. There are 2-many Stamens. The superior Ovary has 2-4 carpels. The flowers are wind pollinated. Fruit is variable with many small wind dispersed seeds. Local genera include Dovyalis, Oncoba, Salix and Scolopia.

The Tree is about 6m high but may reach 8m. The trunk up to 0,6m wide. It can also be a shrub. Branches have conspicuous raised Lenticels (a usually raised corky oval or elongated area on the plant that allows the interchange of gases with the environment) and are glabrous (hairless). Slender, straight, sharp axillary Spines up to 5cm long spines may be present. The Bark is reddish brown in young branches and becomes light brown and smooth. It may be mottled.

Leaves

The Leaves are simple (have a single blade which may have incisions that are not deep enough to divide the blades into leaflets) and alternate. They are usually thin, ovate to elliptic and may reach 16 x 6cm but are usually about half this size. This tree is evergreen, unless there is a cold spell. Margins are boldly or finely toothed / scalloped or smooth. The Blade is coriaceous (with a leathery texture). Leaves are shiny and dark green above. Below they are lighter and duller. The Midrib protrudes on both sides. 4-8 pairs of Lateral veins and net veins are visible on both sides. The Apex tapers somewhat gradually. It may form a drip-tip. The Base is rounded to broadly tapering. Petioles (leaf stalk) are grooved along the top, hairless and up to 1cm long. Stipules (basal appendages of the petiole) are caducous (falling off early).

Flowers

The Flowers buds appear before or with the new leaves. They are round and develop singly from side shoots in leaf axils into impressive, sweetly scented, white flowers. They have a rose like appearance with a central mass of golden yellow stamens. These sweet-scented flowers occur singly on side shoots and are either axillary or terminal. Flowers are bisexual and actinomorphic (regular; symmetrical). The Calyx is pale green with 3-4 lobes which are imbricate (having regularly arranged, overlapping edges, as roof tiles). The Corolla has 7-13 imbricate white, whorled petals which may be wavy. The free Stamens are hypogynous (under the ovary). There is a single Pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma) and the superior Ovary is unilocular (containing a single chamber or cell). The Style is simple. Individual flowers are short-lived but the plant may bloom for 2-3 months. (Sep-Dec).

Fruit

Fruit is indehiscent and almost spherical – up to 6+cm in diameter or is slightly flattened at the apex and base. The fruit has a thin rind that is initially green. This turns yellowish to dark reddish brown. It is hard shelled, faintly ridged longitudinally with a persistent calyx at the base. There is a persistent Style and the Stigma causes a small point or mushroom-like growth at the end. The fruit contains a dry, mealy-like, sour, yellowish pulp. This pulp contains a number of hairless Seeds that are flattish and oval. When the seeds are dry inside they rattle when fruit is shaken. (Feb-Sep).

Distribution & Ecology

These trees are found in Northern KwaZulu-Natal, Limpopo, Mpumalanga, Northern Province, Swaziland, Botswana, Mozambique and northwards to Arabia. It grows on forested stream banks and dry, hot bushveld over a wide range of altitudes.

Ethnobotany

The fruit is edible but not very tasty but may be hollowed out to make snuffboxes. The Wood is light brown but insufficiently large to be of much use apart for use as inlays. The Seeds yield brownish yellow oil but it is difficult to extract. When the seeds are left to dry inside they can be used as children’s rattles. These are often attached to the ankles when dancing. This is an attractive garden tree which is quick growing from fresh seeds or cuttings but is frost sensitive. It grows between 0,5 and 1m per year.

References

Boon, R. 2010. Pooley’s Trees of eastern South Africa. Flora and Fauna Publications Trust, Durban.

Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of Southern Africa, edn 3. Struik, Cape Town.

Lawrence, G. H. M, 1951. Taxonomy of Vascular Plants, The Macmillan Company, New York. Tenth Printing 1965.

Palmer, E. & Pitman, N. 1972. Trees of southern Africa, Balkema, Amsterdam, Cape Town.

Schmidt, S. Lotter, M. & McCleland, W. 2002. Trees and Shrubs of Mpumalanga and the Kruger National Park.

van Wyk, B. & van Wyk, P. 1997 Field guide to Trees of Southern Africa, Struik, Cape Town.

 

http://redlist.sanbi.org/species.php?species=3656-2

http://www.plantzafrica.com/plantnop/voteplant.php

https://en.wikipedia.org/wiki/Oncoba_spinosa

http://tropical.theferns.info/viewtropical.php?id=Oncoba+spinosa

http://toptropicals.com/catalog/uid/Oncoba_spinosa.htm

http://posa.sanbi.org/flora/browse.php?src=SP