General Info

Tree to 8m high, 0,6m wide. Bark – brownish and smooth. Thin, ovate to elliptic Leaves are simple. Stipules fall early. White Flowers with 3-4 sepals + 13 whorled petals. Globose Fruit 6cm wide + hard woody shell.

Description

Oncoba spinosa.

RSA Tree No. 492.

Common names: Snuff-box Tree, Fried-egg-flower.

Family: Salicaceae: (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 the bark often contain Salicin (a bitter alcoholic glucoside related to aspirin). This glucoside can be used as an anti–inflammatory. However, it may cause a skin allergy). Flowers are genetically hermaphroditic, in catkins and usually lacking a normal perianth (a collective term for the calyx and corolla). 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.

Name derivation: Oncoba – from the Arabic name for the North African species. spinosa – spiny. O. spinosa is the only species of this genus in southern Africa.

Conservation Status: L C. (Least Concern). 2009 (Raimondo et al.).

Tree

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 that are up to 5cm long may be present. The Bark is reddish brown in young branches and becomes light brown and smooth. It may be mottled.

Leaves

This tree has alternate; shiny Leaves that are simple (have a single blade which may have incisions that are not deep enough to divide the blades into leaflets). They are usually thin, ovate to elliptic and may reach 16 x 6cm but are usually about half this size. This tree is usually 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 dark green above. Below they are lighter and duller. The Midrib protrudes on both sides. The 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 impressive, sweetly scented, white, bisexual Flowers appear before or with the new leaves. They are round and develop, singly from side shoots in leaf axils, into flowers. They have a rose like appearance with a central mass of golden yellow stamens. These flowers occur singly on side shoots and are either axillary or terminal. Flowers are actinomorphic (having symmetrically arranged perianth parts of similar size or shape that are divisible into 3 or more equal halves). The Calyx is pale green with 3-4 lobes that are imbricate (having regularly arranged, overlapping edges, as roof tiles). The Corolla has 7-13 imbricate white, whorled petals that may be wavy. The numerous free golden Stamens are hypogynous (under the ovary) and have linear anthers. 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) with many ovules. The Style is simple. Although individual flowers are short-lived, the plant may bloom for 2-3 months. (Sep-Dec).

Fruit

The distinctive indehiscent Fruit is and almost spherical or slightly flattened at the apex and base. Fruit diameter is 6+cm. 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. The persistent Style and the Stigma causes a small point or mushroom-like growth at the end. The fruit contains a dry, mealy-like, sour and yellowish pulp. This pulp contains a number of hairless Seeds that are flattish and oval. They have leafy cotyledons. When the seeds are dry inside, they rattle when fruit is shaken. (Feb-Sep).

Distribution & Ecology

These trees are locate 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 edible fruit is not very tasty. It 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