The Tree is usually up to 20m high. Paired spines – 1 straight & 1 curved. The shiny, simple Leaves have 3 clear veins at the base. 5-merous Flowers bisexual, actinomorphic. Fruit a drupe + an elliptic Seed.
RSA No. 447.
Common names: Buffalo thorn, Blinkblaar-wag-‘n-bietjie, Buffelsdoring, Bogwood, Wait-a-bit.
Family: Rhamnaceae. This family of trees and shrubs contains about 58 genera and 900 species. In the RSA, there are 9 genera and 203 species. Genera include Berchemia, Noltea, Rhamnus and Ziziphus. Leaves are simple, usually alternate and stipules are present – if only for a short time. Flowers are actinomorphic (regular and symmetric) and a prominent hypanthium (the cup-like receptacle derived usually from the fusion of floral envelopes and androecium, and on which are seemly borne calyx, corolla and stamens) is present. Sepals and Petals are free and in 4’s or 5’s. The Calyx is tubular and sepals do not overlap. The free petals arise from the calyx tube or from the outer margin of the disc. The 4-5 Stamens arise with, and opposite to, the petals. Anthers have up to 2 pollen sacs and pollen is released through longitudinal slits. The Ovary is usually superior. Fruit is a drupe or capsule and may be partly enclosed by a persistent calyx.
Name derivation: Ziziphus – from the Arabic name for a member of this genus. mucronata – pointed: possibly refers to the sharp thorns or leaf apices. There are 6 species in the genus Ziziphus in southern Africa.
Conservation Status: LC (least concern). 2009 (Raimondo et al.).
The Tree is up to 20m (usually half this size) in height and may have a crooked trunk. Bark may be greenish with clearly visible lenticels (a usually raised corky oval or elongated area on the plant that allows the uncontrolled interchange of gases with the environment) or reddish brown, smooth and often spinescent. Branches are drooping and often zigzagging and may be hairy when young. The bark becomes dark grey, fissured with age – forming small, almost rectangular pieces, and may peel off in strips. The under bark is reddish. Trees are spinescent and spines occur in pairs: one straight (up to 2cm) the other curved sharply backwards. These spines are strong and sharp and more commonly seen in younger stems and are less numerous in forest species.
The Leaves are shiny green above and slightly less so below. They are simple (have a single blade which may have incisions that are not deep enough to divide the blade into leaflets), and entire (with a continuous margin, not in any way indented but may be hairy) or serrate. The leaf arrangement is alternate. The tree is evergreen in coastal areas, where it grows larger, but deciduous in areas subjected to cold winters. Leaves may be hairy. They tend to drupe slightly and are ovate to broadly ovate or widely lance shaped (up to 9 x 6cm). Woolly hairs may be present below. The Apex is broadly to sharply tapering and often mucronate (with a hair-like tip). The Base is markedly asymmetric, tapering on one side and lobed on the other (photo 139). Leaves have 3 conspicuous veins arising from the base. Other, less conspicuous veins may also be visible on the under surface. The Margin is often finely serrated – less so along the lower third and it is often wavy. The Petiole (leaf stalk) is grooved above and up to 2cm long with short, soft hairs. Stipules (basal appendages of the petiole) are distinctive and situated at the nodes on either side of the leaves.
The small yellowish green Flowers are bisexual and actinomorphic (regular, symmetrical. The Perianth – the calyx and corolla are divisible into 3 or more identical sectors or mirror images). Young un-open hairy buds are pentagonal shaped. The small flowers are up to 5mm in diameter and arranged in tight axillary cymes (broad, more or less flat-topped, determinate flower cluster, with central flowers opening first). The Calyx has 5 relatively large Sepals that are keeled within. The Corolla has 5 spatulate (shaped like a spatula with a broad rounded end) Petals that are shorter and a lot thinner than the sepals. A relatively large, flat yellow or cream disc (a more or less fleshy or elevated development of the receptacle) is present which adheres to the calyx tube. 5 Stamens are inserted outside this disc. They become reflexed (photo 898). There is a single Pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma). Immersed in the disc is a superior Ovary. From here, more than one Style arises and each ends in a Stigma that has minute nipple-like projection on the surface. (Oct-Apr).
The Fruit is an almost spherical Drupe (a fleshy, 1-seeded indehiscent fruit with the seed enclosed in a stony endocarp; stone fruit e.g. peach) up to 2cm in diameter. The stony endocarp is very hard and surprisingly wide. I used a saw to cut through the one in photo 910. The fruit is shiny red or reddish-brown and leathery. Large numbers may fall to the ground. It has a thin layer of rather dry sweetish meal-like pulp surrounding a usually solitary elliptic (oval in outline, rest flattish but slightly raised in the centre) Seed. The fruit may remain on the tree until the next green leaves appear (Feb-Aug).
Distribution & Ecology
This Tree is located in a wide range of habitats – especially in summer rainfall areas. The tree is low temperature and drought tolerant and is a relatively common tree in the RSA: especially in the bushveld but excluding the South-Western Cape. The tree is also located in Namibia, Mozambique, Botswana, Swaziland, Lesotho, Ethiopia and Arabia. The tree is susceptible to invasion by Mistletoe (an obligate hemi-parasite that gains moisture and nutrients from the host plant). This hemi-parasite is more visible in winter when its greenish branches become visible on a leafless tree. Rats store Fruit as winter food. Many birds and animals – including giraffe, also eat the fruit. Butterflies including the blue-eyed Pierrot (Zintha hintza), the black pie or dark pied Pierrot (Tuxentius melaena) and the dotted blue (Tarucus sybaris) have larvae which feed on this Tree. The flowers often produce a lot of Nectar. This attracts beetles, wasps, bees, flies and birds.
The presence of these Trees may be an indicator of underground water. Seeds germinate without difficulty. The Spines are extremely vicious – hence the common name “buffalo thorn or wag-‘n-bietjie (wait a while)”. Trees are grown as a natural boundary. Leaves can provide useful fodder and are edible. When cooked they taste like spinach. The pale-yellow Wood has a pale brown centre, a twisted grain and is inclined to warp. It is fine-grained and relatively dense and contains tanning matter, which has peptide alkaloids with anti-fungal properties present. It used for woodworking. The wood makes a good fuel. From the Flowers, an excellent honey develops. The Fruit is edible, but not very tasty by western standards, but consumed by vast numbers of indigenous people – fresh or dried. It is also used to make porridge. If the fruit is roasted and ground, a substitute for coffee can be generated. Another possible use of the fruit is beer making. Studies have shown that Z. mucronate has cyclopeptide alkaloids that have antibacterial properties. This has led to proposed conservation strategies to sustain and maintain the tree, which may become as popular as Z. jujuba and Z. mauritiana, which are utilised especially in China and India as medicinal plants.
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. Page 666
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.