General Info – summary

This magnificent frost sensitive evergreen & wide spreading Tree has a roundish canopy & may reach 18m+ high.  It usually has several combined trunks.  Imparipinnate Leaves have leaflets with entire margins & asymmetric bases.  Creamy-white, bisexual, zygomorphic & 5-merous Flowers are in axillary racemes and have superior ovaries & short styles.  Fruit is reddish brown and drupe-like with a single shiny black seed.

Description

Xanthocercis zambesiaca

Previous Names: Pseudocadia zambesiaca, Sophora zambesiaca.

SA Tree No. 241.

Common names:  (Afr) Hoenderspoor, Njalaboom.  (Eng) Nyala-tree, Nyala Tree.  (Setswana) Mhota, Moladi, Motlha.  (siSwati) Umhlwati.  (Tshivenda) Mutshato.  (Xitsonga) Nhlahu.

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 – even bilobed 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: Xanthocercis – Xantho: yellow, cercis: from the genus Cercis. (a non indigenous member of the Fabacee.  zambesiaca of the Zambezi region.

Conservation: National Status: L C (Least Concern).  Assessed: 2005 (W. Foden and L. Potter).

Tree

The roundish canopy on this impressive Tree (photo 431) helps it to reach up to 18m high and wide.  This tree may occasionally reach 30m high.  The much-fluted Trunk is stout and may initially contain the combination of several vertical Branches increasing the trunk “diameter” to about 2,4m.  Upper branches are slender and drooping.  Young twigs are pale yellowy brown, covered with short soft hair, and have a slightly zigzagging growth pattern.  Other branches are long and slender and tend to hang down – especially towards the ends.  Present on older branches are indistinct Lenticels (usually raised corky elongated areas on the plant that allows the uncontrolled interchange of gases with the environment).  The dark grey to brown, non-pealing Bark becomes fluted, rough and cracked into small pieces (photo 35).

Leaves

The Leaves on this evergreen tree tend to droop and are imparipinnate (pinnately compound leaf ending in a single leaflet – photos 36 & 37).  Here the Rachis (main leaf axis) is hairy (photo 38).  Each leaf has 3 to 7 pairs of nearly opposite or alternate Leaflets plus the largest terminal one, which is up to 5,5 x 2cm.  The oblong leaflet Blade is glossy and dark green above and much lighter below (photos 38 & 39) where the venation is clearly visible.  Here the lateral veins do not go directly to the margin.  The Margin is entire (with a continuous margin, not in any way indented).  The Apex is usually notched (photo 39) to rounded and the asymmetric (not equal to the opposite side) Base (photo 38) is rounded to broadly tapering.  The Midrib protrudes below and usually grooved above (photos 39 & 38).  The hairy Petiole (leaf stalk) is pulvinate (having a swelling at the base (photo 36).  The Petiolules (leaflet stalks) are short and hairy (photo 38).  Stipules (basal appendage of the petiole) are small.

Flowers

The mauve-white hanging sprays of pea-like Flowers are up to 10cm long.  They are rose scented and occur in terminal or axillary Racemes (a simple elongated inflorescence with stalked flowers that open in succession towards the apex).  Individual bisexual flowers are zygomorphic (irregular flower: when corolla is divisible into 2 equal halves in one plane only).  These flowers only have a slight resemblance to those of a sweet pea.  Bracts (a much-reduced specialised leaf, particularly the small scale like leaves in a flower cluster or associated with flowers) are present and are caducous (an organ or part which is easily detached and shed early).  The greyish velvety Calyx has a bell-shaped tube with short lobes.  The Corolla has 5 unequal white or creamy yellow Petals, which arise from the base of the calyx tube.  The upper hairy Vexillum or standard petal is outermost and only slightly larger than the other petals.  The remaining 4 petals are similar.  Unlike the pea-type flower, there are no joined keel petals.  The 10 Stamens arise with the petals.  Nine of them are joined and the tenth one, adjacent to the vexillum, is free.  The Anthers are oblong.  An annular Disc (a more or less fleshy or elevated development of the receptacle) is present.  There is a single Pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma) containing a superior Ovary on a short stalk.  The short Style ends in a lateral Stigma.  (Sep-Dec).

Fruit

Unlike most members of the Fabaceae, the stalked Fruit is not in a pod.  It is plumb-shaped, reddish brown and Drupe-like.  It resembles a berry (photo 40) and is up to 2,5 x 1,7cm.  Initially a flowery, fleshy pulp encloses the usually single Seed, which has a shiny-black Testa (seed coat – photo 42).  Photo 44 shows a cross section of the ripened fruit revealing the 2 white cotyledons (seed leaves; primary leaves of the embryo).  (Nov-Jun).

Distribution & Ecology

In South Africa, these Trees are located in Limpopo (between the Soutpansberg and the Limpopo River).  Attractive specimens are present at Chipise (close to Messina and the Zimbabwe border.  They also occur in Mpumalanga (Northern part of the Kruger National Park especially near Pafuri).  Insects are responsible for pollination.  This plant is a southern Africa endemic (restricted to a particular geographic location).  Beyond South Africa, the plant grows in Mozambique, Swaziland, Zimbabwe, Botswana and Zambia.  These trees are commonly found in hot areas along lowveld (land areas that lie at an elevation of between 150 and 600 metres and occur in parts of Kwazulu-Natal and Mpumalanga as well as Swaziland, northern Botswana and southern Zimbabwe.  Elephants, Giraffe and Nyala feed on the Leaves.  The Fruit attracts birds including Green Pigeons, Brown-headed parrots, Grey and Yellow-billed Hornbills and Brown-headed Parrots.  Baboons, monkeys, buck (especially the Nyala) and elephants feed on the fruit.  Bushbuck, impala and guineafowl consume fallen fruit – often dropped by the feeding birds.  The ripe young seedlings often grow below the parent plant.  In the hot summers, this is a sought-after tree for its impressive dense shade.  Seeds germinate easily.  Plants, including the slow growing seedlings are frost and drought sensitive.  They grow best in clay soils usually up to 75m from rivers.  They also are associated with termite mounds.

Ethnobotany

The Seeds are eaten fresh.  They may be buried for a few weeks before being made into porridge.  The seeds may also be dried and crushed into a coarse meal.  The dense white, fine textured Wood is hard and finishes with a smooth appearance.  The wood is used as fuel.  Sawdust is irritating to the eyes, nose and throat.  Crushed Leaves have an unpleasant smell.  In the right large environment, this tree provides good, dependable shade and is ideal for large gardens.

References

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

Burrows, J.E., Burrows, S.M., Lotter, M.C. & Schmidt, E. 2018. Trees and Shrubs Mozambique.  Publishing Print Matters (Pty) Ltd.  Noordhoek, Cape Town.

Foden, W. & Potter, L. 2005. Xanthocercis zambesiaca (Baker) Dumaz-le-Grand. National Assessment: Red List of South African Plants version. Accessed on 2024/04/14.

Ginn P.J. Mcilleron W.G. and Milstein P. le S, 1989. The Complete Book of Southern African Birds. 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. Jacana, Johannesburg.

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

 

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

http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=131230

http://tropical.theferns.info/viewtropical.php?id=Xanthocercis+zambesiaca

http://mozambiqueflora.com/speciesdata/species.php?species_id=131230

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

http://pza.sanbi.org/xanthocercis-zambesiaca