This small Tree has resinous branches and simple, entire Leaves. The small Flowers lack petals and are anemophilous. Fruit is a capsule with 2-3 membranous wings. Seeds are small, dark and shiny.
Dodonaea viscosa var. angustifolia, Ptelea viscosa, Dodonaea thunbergiana.
RSA Tree No. 437.
Common names: Sand-olive, Makkaree, Sandolien.
Family: Sapindaceae. (Soapberry family). This family has 135 genera and about 1 800 species. The alternate, usually compound Leaves often lack stipules (leaf stalk) and have a swollen base. The small, usually unisexual, Flowers may be regular or irregular. The Calyx has 4-5 lobes and, when present, the Corolla has 3-5 petals. There are between 5 and 24 Stamens, which have free Filaments and the Anthers have 2 pollen sacs. The superior Ovary may have up to 3 styles each ending in a simple stigma. There are 27 species in 14 genera in southern Africa. Local genera with trees include Allophylus, Atalaya, Dodonaea, Erythrophysa, Filicium, Hippobromus, Pappea, Smelophyllum and Stadmannia.
Name derivation: Dodonaea – after Rembert Dodoens (1517-1585); a botanist and professor of medicine at Leiden. His book “Histoire des Plantes” was translated and used as a reference book for more than 200 years. viscosa sticky – referring to the gummy leaves.
Conservation Status: L. C. Least Concern. (2009 Raimondo et al.).
This Tree is usually up to 5m high with low branches but may reach a height of 9m. It is often a multi-stemmed shrub. The Bark is grey and finely fissured. Small branches may be reddish or brown and longitudinal striated. Twigs (1-year-old current branch segments) are resinous and angular.
The hairless and variable Leaves on this evergreen plant are glossy, light olive green above and lighter below. They are simple (have a single blade which may have incisions that are not deep enough to divide the blade into leaflets) and the margins are entire (with a continuous margin, not in any way indented but may be hairy). Leaves may be wavy and are sticky and resinous. They are arranged alternatively or spirally and their shape is elliptic to oblanceolate and usually up to 10 x 2,7cm. In Dodonaea viscosa var. viscosa the leaves are much wider – up to 4,2cm wide. The Apex and Base are both narrowly tapering. The Midrib is clearly visible on both sides but less so towards the apex. The veins are more clearly visible below and are best seen when viewed against a strong light (photo 359). The Petiole (leaf stalk) is up to 6mm long and Stipules (basal appendages of the petiole) are absent. (Apr-Sep).
The small, stalked, greenish yellow Flowers appear in leaf axils or in branched terminal heads. They are either monoecious (having both male and female reproductive organs on the same plant), dioecious – the usual condition (having male and female parts on separate plants) or they may be bisexual. There are 4 Sepals. Petals are absent. This may be an anemophilous (wind pollination) adaptation. In the Male flowers there is a vestigial disc (a more or less fleshy or elevated development of the receptacle) present from which the 8 Stamens, with their free Filaments, arise. The anthers have 2-theca (2 pollen sacs) and are longer than the filaments. Here the ovary is rudimentary. In the Female flowers, the anthers are sterile or absent. The superior Ovary has 2 Ovules in each Locule. 3 Styles are present and the Stigma is simple. (Apr-Aug).
The 3-winged Fruit is a membranous Capsule (a dry fruit resulting from the maturing of a compound ovary, which usually opens at maturity by one or more lines of dehiscence). It is up to 15mm wide and contains 2-3 papery wings. The impressive fruit appears in large numbers and remains on the tree for a long time. Capsules only develop on female or bisexual plants. The papery Wings highlight the dispersion by wind. As they mature – which can take 11 months, they change from light green to pink and finally brown. The small, dark shiny Seeds are without endosperm (the starch and oil-containing tissue of many seeds; often referred to as the albumen).
Distribution & Ecology
These Tree are found from coastal dunes, woodland, disturbed areas, flat areas, within mountains, dry forest and in wide ranging rainfall areas. They are often found on rocky, wooded hill slopes. These plants are located in the Western Cape, Eastern Cape, Kwa-Zulu Natal, Northern Gauteng, Swaziland, Mpumalanga Namibia and Northwards into tropical Africa. They also occur in Australia and are widespread in South America. The plants are used to help stabilise sand. Viscum capensis is a bird dispersed Hemi-parasite which may grow on the stems.
The plant is used in local medicine and is easily grown from seeds or cuttings. Seeds should be soaked in hot water beforehand. It is a useful, hardy, fast growing, garden plant that is drought and fire resistant. It should be planted in direct sunlight. This will allow the red fruit colour to be emphasised. The Wood is very hard and may be used for walking sticks, axe handles etc. It is also used as fuel.
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.