Common names: (Afr) Boerboon, Boerboontjie, Dopperkehatenhout.(Eng) African Black Wattle, African Blackwood, Black Wattle
Family: Fabaceae or Leguminosae. (Pea, bean or legume family). After the Orchidaceae and the Asteraceae, the Fabaceae is the third largest Angiosperm (flowering plants) family with 700+ genera and close to 20 000 species. Local Tree genera on this website include Acacia (Vauchellia, Senegalia), Albizia, Bauhinia, Bolusanthus, Burkea, Calpurnia, Colophospermum, Cordyla, Cyclopia, Dichrostachys, Erythrina, Erythrophleum, Faidherbia, Indigofera, Mundulea, Peltophorum, Philenoptera, Piliostigma, Schotia and Xanthocercis.
The Fabaceae are recognisable by their fruit and by their pinnately compound Leaves. Leaves may also be simple and usually have stipules – some of which may be spinescent. Leaflets are usually entire. Flowers are bisexual and bracteate.
Regular flowers usually have 4-5 sepals and the same number of petals. Irregular flowers have 4-5 sepals and 5 or less petals. Stamens have anthers that have 2 pollen sacs and there are usually at least twice the number of stamens as petals – often 10. The superior Ovary has one locule that may contain 1 or more ovules. The Stigma and Style are simple. The single carpel develops into the Fruit, which is usually a pod. This pod dehisces on both sides and may break into segments. Seeds vary.
Name derivation: Peltophorum – shield shaped – referring to the stigma (green in the intro photo). africanum – from Africa. This is the only species of Peltophorum in South Africa. The fact that this plant lacks spines helps to distinguish it from the genera Senegalia and Vachellia.
Tree, Fruit and Leaves
There are no spines or thorns present on this Tree. It has a spreading untidy crown and is usually 5-10 but may reach 15m high. Branches often occur near the ground and may be crooked or forked close to the ground.
The Trunk is often multi-stemmed. The Bark on an older trunk can be grey to brown, rough and become longitudinal fissured.
Twigs (1-year-old current branch segments) have lenticels (usually raised corky oval or elongated area on the plant that allows the uncontrolled interchange of gases with the environment). Twigs are covered with rusty coloured hairs.
The flattish, drooping and indehiscent Fruit is a Pod, which is oblong to elliptic (oval in outline and widest near the middle).
The pods taper toward both the apex and base. A distinct wing is visible along both margins. The remains of the Calyx may be visible at the base of the fruit.
Each fruit is up to 10 x 2cm. It is thinly woody, slightly leathery and green to yellowish becoming red-brown. Fruit hangs down in clusters.
Seeds are brown and flattish, and about 11 x 7mm. Usually 1 or 2 compressed and slightly winged seeds develop in each fruit. (Dec-Jun).
This tree may be deciduous. The feathery, silvery grey Leaves are similar to those of “acacia”. They are bipinnate (compound: twice pinnate. The central axis or rachis has lateral “branches” not leaflets and the leaflets are on these “side branches”).
The furry Growing tip is often rusty brown and young Leaflets are folded lengthwise. The small leaflets are usually about 7 x 2mm. They are oblong and slightly spaces apart. Each is dull olive green above and paler green below. The Apex is rounded with a fine distinctive hair-like tip.
The Base is asymmetric and the Margins are entire (with a continuous margin, not in any way indented). The leaf Rachis is grooved on the upper surface. Rusty brown, velvety Hairs envelope the Petiole (leaf stalk) rachis (main axis bearing flowers or leaflets) and Leaflets. The distinctive feather shaped Stipules (basal appendages of the petiole) are small. They appear like tiny ferns but are caducous (an organ or part of which is easily detached and shed early).
Distribution & Ecology
These Trees are located in KwaZulu-Natal, Gauteng, Mpumalanga, Limpopo and North West. Beyond South Africa, they occur in Botswana, Namibia, Angola, Swaziland, Mozambique, Zimbabwe, Zambia, Tanzania, Kenya and DRC.
Major habitat: medium to low altitude: Grassland Savanna (is a rolling grassland scattered with shrubs and isolated trees, which can be found between a tropical rainforest and desert biome).
Trees also occur in Bushveld, deciduous Woodlands, on rocky outcrops, on riverbanks, on sandy soil and margins of vleis (shallow, small, seasonal lake or pond or marshy wetland). Larvae of the Butterfly Satyr Emperor (Charaxes ethalion) and of Van Son’s Emperor (Charaxes vansoni) feed on the Leaves. Game including giraffe, elephant, and kudu browse the leaves. Black rhino strip and consume the Bark.
After the start of the rainy season, plant-sucking nymphs of Spittlebugs (Ptyelus grossus) encase themselves in protective acrid foam froth and cause this and other trees to “rain”.
This would make a good avenue tree. The close grained, fairly hard and tough Wood has reddish heartwood. It is suitable for carving after seasoning. At one stage, it was one of the woods used in wagon making.
Seasoning is necessary to prevent borer attack. After seasoning, it can also be used for furniture and even for buckets. The wood is also used for fuel. It is a good garden and shade tree. The plant grows quite quickly from seed and is slightly resistant to dry times and, once established, to frost.
Roots are non-invasive. The Fruit is used for feeding goats and cattle. Food. Local people consume the large green spiny lava of the moth Gynanisa maia which feeds on the leaves. The Gum may be poisonous.
In some communities, the presence of this tree is believed to give the feeling of comfort and freshness. Some believe that planting the tree together with sown corn will attract rain. The tree has many medicinal uses.