This dioecious, single stemmed Tree may reach 6m high. Pinnately compound Leaves to 3m long Leaflets at leaf base reduced to prickles. The oblong female Cones may reach 45 x 11cm and release scarlet Seeds up to 3,5 x 2cm.
Common names: Natal Cycad, Prickly Giant-cycad, Giant Cycad.
Family: Zamiaceae. This is a family of perennial cycads has 8 genera and about 200 species. They are only superficially palm or fern like. The cycad tap Root is soon replaced by lateral roots, which become woody. Cycads have coralloid roots that contain symbiotic cyanobacteria (blue-green algae) that fix atmospheric nitrogen in association with root tissue and produce important amino acids for the plant. Stems are cylindrical and southern African species do not have persistent leaf bases. All are evergreen with pinnately compound Leaves. The Leaflets have parallel (or nearly so) veins.
Name derivation: Encephalartos – within-head-bread: referring to the starchy bread that can be made from the pith of the inner trunk. natalensis – from Natal province – now Kwa-Zulu Natal. The African plants in the genus Encephalartos include about 66 species. There are about 30 species in southern Africa. The genus Encephalartos includes some of the most primitive living Gymnosperms.
The genus Encephalartos includes some of the most primitive living Gymnosperms. Unlike other members of the family Zamiaceae, species in the genus Encephalartos have leaflets that lack a central Midrib (vein). Diamond shaped leaf scars remain on the trunk. The hard prickly leaflets do not bend easily. The sunken leaf veins are parallel or almost so. Stomata (structure utilising 2 guard cells, which unlike lenticels can control the gaseous exchange) are present on the lower surface and may occur above. All species are dioecious with male and female Cones on separate plants. These cones develop in the centre of the leaf whorls. At maturity, the Seeds are released when the Female cones disintegrate. All species produce poisonous glycosides (cycasins). The African plants in the genus Encephalartos include about 66 species and there are about 30 species are in southern Africa.
Conservation Status: Near Threatened. Assessment Date: 2009.10.31 (J. S. Donaldson). Illegal harvesting and use in the traditional medicine trade have had an effect.
The Stem may be branched from the base and the Tree is up to 4-6m high. When branched, the main stem may recline. The trunk may be up to 40cm wide.
Cycads are unique Gymnosperms with compound Leaves. Leaves are pinnately compound (leaflets arranged along either side of leaf rachis – a central stalk) and palm-like. These evergreen trees have glossy-green leaves that are up to 3m in length with a Rachis (in this case an axis bearing leaflets) that may twist close towards the end of the leaf. The Leaflets near the centre of the leaf are the largest and are broad – up to 23 x 5cm. They are usually untoothed but may have up to 5 prickles on one or both sides. Towards the base of the leaf, the leaflets are reduced in size to prickles. Where the new leaves arise, the crown is woolly and gold coloured – becoming more so when new cones are produced.
The trees are Dioecious (having male and female cones on separate plants) and 2-3 orangish-yellow cones may occur together on both male and female cones. Male Cones are cylindrical, velvety and usually about 45 x 11cm in size. Pollen is shed from April to June. These cones are initially covered with brown hair. Female Cones are more or less oblong and larger – about 55 x 25cm. The mature female cones break up exposing and releasing the up to 500 Seeds. The scarlet seeds are up to 3,5 x 2cm.
Gymnosperms have unenclosed or naked seeds. They have no flowers or fruit and the seeds are often contained in cones. In the Angiosperms (flowering plants), the seeds are enclosed in an ovary. In the Gymnosperms, there are 2 modes of fertilization. In all the Cycads (including Encephalartos) and the single extant (not extinct) species of Ginkgo (Ginkgo biloba), the male cones produce motile sperms. The remaining members of the Gymnosperms all have non-motile sperm with no flagella and are moved along with a Pollen tube to the egg.
Distribution & Ecology
These Trees may occur from Vryheid in the Eastern Cape to Tabankulu, which is NNW of Port St Johns in KwaZulu-Natal. This tree is only found in inland areas. Trees can be seen in the gorge below the Howick Falls (KwaNogqaza). They are found in krantzes (encircling or overhanging wall of rock) and rocky valleys in the region of 1 200m altitude. The trees are frost hardy. The Leopard Magpie moth (Zerenopsis lepida) can severely damage the leaves of this and many other cycads. The Bats, baboons, monkeys and trumpeter hornbills eat the outer part of the Fruit. The leftover poisonous Seeds are thus dispersed.
This Tree is relatively quick growing. Plant young trees in a rocky, somewhat shady, area. The Seeds are poisonous and should be handled with gloves.
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.
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.
van Wyk, B. & van Wyk, P. 1997 Field guide to Trees of Southern Africa, Struik, Cape Town.