Dioecious Tree is up to 4m high. Pinnately compound Leaves are up to 2m long and leaflets have prickles on both sides. Leaflets at the leaf base are reduced to prickles. Up to 2 male and 3 female Cones present. Seeds are glossy red.
RSA Tree No. 14.8.
Common names: Piet Retief Cycad, Piet Retief broodboom.
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. lebomboensis – grows in the Lebombo Mountains (from Hluhluwe in KwaZulu-Natal in the south, through Mpumalanga and to Punda Maria in the Limpopo Province in the north. Part of the mountains are also occur in Mozambique and Swaziland).
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. Their sunken leaf veins are parallel or almost so. Stomata (structure utilising 2 guard cells that, unlike lenticels, can control the gaseous exchange between the plant and the surrounding atmosphere) 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 occur in southern Africa.
Conservation Status: E N. (Endangered). Assessment Date: 2009.10.31 (J.S. Donaldson). The population trend is decreasing. This is caused by illegal collection and for its use in traditional medicine. Depending on who identifies the plant, the status of some plants could be critically endangered.
This Tree may reach 4m high and the Trunk is usually vertical or reclining. It is unbranched and up to 30cm in diameter. Small and large leaf bases, due to climatic changes, may result in patchwork patterns. Like annual rings, these remains may help provide a history of climate fluctuations. The trunk has a large pith. The tree may sucker from the base, producing up to 8 stems. The crown may become quite woolly at coning time.
Cycads are unique Gymnosperms with pinnately compound Leaves (leaflets arranged along either side of the leaf rachis, the central stalk, like a feather). Leaves form a dense crown at the end of the trunk. Leaves are stiff, straight or slightly recurved near the end. They are up to 2m x 27cm. Young leaves are hairy but mature leaves are hairless and may remain on the trees for more than a year. The closely spaced Leaflets have parallel veins and overlap downwards. Individual leaflets are sickle-shaped. They are glossy, mid to dark green above and lighter below. Each leaflet measure up to 17 x 2cm. They usually have up to 4 prickles on both Margins. Leaflets near the leaf bases, are reduced to spines. The Petiole (leaf stalk) contains spines for its entire length.
Like most gymnosperms, the cycads produce cones not colourful flowers. The tree is Dioecious (having male and female cones on separate plants) and the sex of the tree is difficult to determine until the cones appear. Up to 3 bright yellow or slightly pink Female Cones grow together and each up to 45 x 30cm. Each egg-shaped cone bares 2 naked ovules on the upper surface of each scale. There are usually 1 or 2 Male Cones on short stalks. They are thin, narrowly cylindrical and yellowish-green. Each cone is up to 45 x 14cm. Pollen is contained in dense packets on the lower surface of the cone scales. The visible upper surface of scales on the male cone is raised and slightly flat. The shiny, scarlet Seeds are smooth, glossy red and about 4 x 2,2cm. The tree is insect pollinated and monkeys and baboons disperse seeds.
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 grow on rocky slopes and cliffs e.g. Lebombo mountains in Mpumalanga (running through Piet Retief). Many of these cycads originally classified as E. lebomboensis are now regarded by as E. senticosus. The differences are dependant of the number, size and form of the cones. Encephalartos lebomboensis are also found in northern KwaZulu-Natal (Paulpietersburg), Swaziland and Mozambique. The tree is resistant to fire and drought.
These tree may be becoming extinct in the wild. They grow in full sunlight in a misty environment with hot wet summers. The size of remaining leaf bases has been used to determine historical rainfall – much like annual rings on some trees. Trees are semi-hardy to frost and are a popular plant in households. They can be grown from suckers or seeds and have the ability to transplant readily. They require good drainage and do best on a slope.
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.
Schmidt, S. Lotter, M. & McCleland, W. 2002. Trees and Shrubs of Mpumalanga and the Kruger National Park.