General Info

Tree may reach 18m+ high. Leaves are imparipinnate: terminal leaflet largest. The creamy-white, bisexual, zygomorphic Flowers in racemes. Fruit: reddish brown Drupe with a shiny black Seed.

Description

Tree

Xanthocercis zambesiaca, Pseudocadia zambesiaca, Sophora zambesiaca.

RSA Tree No. 241.

Common names: Nyala Tree, Nyala-tree.

Family: Fabaceae or Leguminosae are Angiosperms (flowering plants) and commonly referred to as the pea, bean or legume family. After the Orchidaceae and the Asteraceae, the Fabaceae is the third largest Angiosperm family with 700+ genera and close to 20 000 species. Local genera include Acacia (Vauchellia, Senegalia), Albizia, Bauhinia, Bolusanthus, Burkea, Colophospermum, Cyclopia, Erythrina, Erythrophleum, Indigofera, Philenoptera and Schotia. 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. The pod dehisces on both sides and may break into segments. Seeds vary.

Name derivation: Xanthocercis – Xantho: yellow, cercis: from the genus Cercis. zambesiaca of the Zambezi region.

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

This Tree with a roundish canopy is usually up to 18m and occasionally reaches 30m high. The Trunk is stout and may contain, at least initially, the combination of several vertical Branches. Branches are thinnish and tend to droop especially towards the ends. The Bark is dark grey to brown and rough. It becomes fluted, rough and cracked into small squares.

Leaves

The Leaves are imparipinnate (pinnately compound leaf ending in a single leaflet) and tend to droop. There are 3-7 pairs of nearly opposite Leaflets plus the largest terminal one. Each is up to 5,5 x 2cm. The Blade of the leaflets is glossy and dark green above and much lighter below where the venation is clearly visible. The Margin is entire (with a continuous margin, not in any way indented but may be hairy) and the Rachis (main leaf axis) is hairy. The Apex is notched to rounded. The Base is rounded to broadly tapering. The Midrib protrudes below and is usually grooved above and slightly swollen at the base. The Petiole (leaf stalk) is hairy and the Petiolules (leaflet stalks) are short and hairy. Stipules (basal appendage of the petiole) are small.

Flowers

The creamy white hanging sprays of Flowers are in axillary racemes (a simple elongated inflorescence with stalked flowers that open in succession towards the apex) which are up to 10cm long. Individual flowers are bisexual, zygomorphic (irregular flower: when corolla is divisible into 2 equal halves in one plane only) and scented like a rose. These flowers have only a slight resemblance to those of a sweet-pea. Caducous (an organ or part which is easily detached and shed early) bracts are present. The greyish velvety Calyx has a bell-shaped tube with short lobes. The Corolla has 5 unequal white or creamy yellow unequal Petals, which arise from the base of the calyx tube. The upper Vexillum or standard petal is outermost, hairy and slightly larger than the rest. The remaining 4 petals are similar. Unlike the pea-type flower, there are no joined keel petals. The 10 Stamens arise with the petals. 9 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

The Fruit is unusual for this family. It is plumb-shaped, reddish brown Drupe (a fleshy, 1-seeded indehiscent fruit with the seed enclosed in a stony endocarp; stone fruit e.g. peach), which resembles a berry. It is up to 2,5 x 1,7cm. (Nov-Jun). A flowery, fleshy pulp encloses the Seed, which has a shiny-black Testa (seed coat).

Distribution & Ecology

These Trees are located in Limpopo (between Soutpansberg and the Limpopo River) and Mpumalanga (Northern part of the Kruger National Park especially near Pafuri), Mozambique, Swaziland, Zimbabwe, Botswana and Zambia. Commonly found along watercourses, flood plains and termite mounds at low altitudes and in hot areas. Elephants, Giraffe and Nyala feed on the Leaves. The Fruit is consumed by elephant, buck – especially the Nyala, baboons and monkeys. This is a sought-after tree for its shade in the hot summers.

Ethnobotany

The Fruit is edible and can be eaten raw or crushed to make porridge. It can also be dried and crushed into a coarse meal. The Wood is white, dense, hard and finishes with a smooth appearance. Sawdust is irritating to the eyes, nose and throat. The wood used as fuel. Propagation. Seeds germinate easily and young seedlings are often found around the parent plant. They are rather slow growing and are frost sensitive. Crushed Leaves have an unpleasant smell.

References

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=235-1

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