Tree to 20m high. Lacks spines. Bipinnate Leaves: 18cm long, leaflets large. Small, bisexual actinomorphic whitish Flowers. Stamens exserted. Style long. Fruit: a flat pod with wind dispersed Seeds.
Albizia versicolor, Albizia mossambicensis.
SA Tree No. 158.
Common names: Large-leafed False-thorn, Large-leafed Albizia, Poison Pod Albizia, Grootblaar-valsdoring, Umvanghaas.
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 genera include Acacia (Vauchellia, Senegalia), Albizia, Bauhinia, Bolusanthus, Burkea, Calpurnia, Colophospermum, Cyclopia, Erythrina, Erythrophleum, Faidherbia, 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: Albizia – named after F. del Albizzi who introduced the plant into Italy in about 1749. versicolor – variety of colours of spring leaves. In the RSA there are 11 indigenous species in the genus Albizia.
Conservation Status: L C. (Least Concern). 2009 (Raimondo et al.).
Unlike the “Acacia” Trees, the species of Albizia all lack spines. This is a medium to large tree may reach 20m high. It has a cylindrical trunk with a diameter up to 1,5m. The Crown is rounded to spreading. The tree is usually single or somewhat multi-stemmed. The Bark is grey-brown, very rough and corky. Branchlets are hairy.
The Leaves are bipinnate (compound: twice pinnate. The central axis or rachis has lateral “branches” not leaflets and the leaflets are on these “side branches”) and have coloured hairs. Young leaves are a pinkish red (photo 596). Mature leaves are large – up to 25cm long. There are up to 5 pairs of pinnae which support up to 6 pairs of large leaflets. The large: up to 6 x 4,5cm and leathery Leaflets are broadly hairy on both sides. They are elliptic to ovate. The largest leaflets occur near the apex. The Apex is rounded or shortly pointed. The broadly tapered Base is not narrowed. The yellow Midrib and veins are clearly visible below. Leaflet Margins are Entire (with a continuous margin, not in any way indented but may be hairy). The hairy Petiole (leaf stalk) is up to 7,5cm long and has a gland near its base. It is grooved on the upper surface. Petiolules (stalk of leaflet) are present. Stipules (basal appendages of the petioles) are present on new leaves. Stipels (secondary stipules situated at the base of a leaflet of a compound leaf) are absent. (Oct-Dec). In autumn, the leaves turn yellow.
On this deciduous tree, the Flowers appear with the new leaves. They are bisexual and actinomorphic (regular, symmetrical. The perianth, the calyx and corolla, are divisible into 3 or more identical sectors). Flower stalks are up to 6cm long and the inflorescence is half-spherical. The Perianth (a collective term for the calyx and corolla) is biseriate (calyx and corolla are in two distinct whorls). The Calyx is up to 8mm long, has 5 lobes and is gamosepalous (a calyx whose sepals at least partly united). The Corolla has 5 white Petals with a funnel-shaped base. The initially white flowers turn a pinkish yellow. The numerous Stamens are united at the base. Thereafter the long Filaments – up to 7cm, are exserted (sticking out; projecting beyond). They are creamy white and help to give the flower its colour. The Anthers are peltate (shield-shaped) and the Theca (pollen sacs) open outwards. There is a single Pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma). The Ovary is stalk-less or nearly so and superior (one that is free from the calyx or perianth). There is a single filiform (thread or filament like) Style which is longer than the anthers. The Style ends in a single Stigma. (Sep-Dec).
The thin, flat and wide Fruit is a dehiscent Pod that is up to 22 x 5cm. It is glossy, reddish brown when mature and usually contains up to 6 seeds. The margins may be thickened. Seeds have a filiform (thread or filament like) Funicle (the stalk by which the ovule is attached to the ovary wall or placenta). Seeds are wind dispersed. (Dec-Mar).
Distribution & Ecology
This is a common lowveld tree – usually below 1 500m. It occurs in mixed woodland in KwaZulu-Natal, Mpumalanga e.g. Pretoriuskop and Punda Maria, Limpopo, Swaziland, Mozambique, Namibia, Angola and up into central Africa. It usually occurs close to water and on mountain slopes. The Brown-headed Parrot eats the Seeds. Elephant and antelope e.g. Kudu browse the Leaves. The Nectar attracts honeybees. Nitrogen-fixing bacteria help the tree and increase soil fertility.
The good quality Wood is similar to Kiaat (Pterocarpus angolensis). It has a good grain and may have a purplish brown or black heartwood. The sapwood is white. Once dry, the wood is stable. Sawdust can cause sneezing. Wood is used for carving, furniture, drum and mortar making. The wood is also used as fuel and for charcoal manufacture. Seeds and pods – especially when young are crimson coloured, and are toxic to stock. Strong winds blow these young Pods from the trees. They contain methylpyridoxine, which is also found in Ginkgo biloba. It causes a disease called albiziosis, which can be fatal. This is a serious problem. It can be treated with high doses of pyridoxine hydrochloride (a vitamin B6). Old pods are less toxic. Soap can be made from powdered root bark and leaves. Tanning material, which, contains about 5% tannins and fibre is extractable from the bark. The tree is assumed by some to be an indicator of underground water. This is a good ornamental shade tree and the roots are not invasive. Trees grow up to 80cm per year and do best in well-drained soils. Because of the toxic pods, it is best to avoid planting in areas where grazing may occur. About 8 000 seeds have a mass of 1kg.
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