This dioecious Tree is up to 4m high and may sucker from the base. Leaves pinnately compound, lowermost leaflets reduced to prickles. 1-5 mature female Cones are yellow.
Encephalartos dyerianus, Encephalartos graniticolus.
RSA Tree No. 14.2
Common names: Lillie’s Cycad; Lillie-se-broodboom.
Family: Zamiaceae. This is a family of perennial cycads with 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.
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 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: Critically endangered. Assessment Date: 2009/10/31. This is due to illegal collecting. These plants are for sale in the USA.
Description. This cycad Trunk may reach to 4m high and has a diameter of up to 60cm. It may sucker from the base. This cycad is woody with almost palm-like trees.
All Cycads are unique Gymnosperms with pinnately compound Leaves (leaflets arranged along either side of the leaf rachis or central stalk like a feather) and are moderately keeled. Here the leaves are relatively straight and up to 1,7m long. The leaf apex may be slightly twisted or recurved. Leaf bases remaining on the tree after the leaves have fallen. Leaves are slightly persistent – lasting longer than 1 year. The Rachis (main axis bearing flowers or leaflets) is slightly stiff. The straight Petiole (leaf stalk) has up to 6 prickles. The non-overlapping Leaflets are bluish green or silver and almost concolorous (uniform colour). They turn slightly yellow. Each leaflet is up to 24 x 2cm. The median leaflets are the largest. The opposite leaflets are arranged at about 110° on the rachis. The lowest leaflets are reduced to prickles. Parallel Veins are clearly visible and Stomata (structure utilising 2 guard cells, which, unlike lenticels, can control the gaseous exchange between the plant and the surrounding atmosphere) occur on both surfaces. The Margin is either entire (with a continuous margin, not in any way indented but may be hairy) or with up to 3 small spines. The base of Petiole (stalk of a leaf) has a prominent collar.
This tree is dioecious (having male and female cones on separate plants). The initially bluish green Cones turn yellow at maturity. They are borne on distinct stalks over 6cm long. 4-7 yellow Male cones develop. There are up to 5 yellow Female cones which are and have naked ovules. The oblong Seeds are up to 4,5 x 3cm.
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 living species of Ginkgo (Ginkgo biloba), the male cones produce motile sperms. Whereas, the remaining members of the Gymnosperms all have sperm with no flagella and are moved along with a pollen tube to the egg.
Distribution & Ecology
These Cycads are located on open grassland and shrub land on the slopes of low granite (Granite – an igneous rock that develops underground when silica rich molten rock cools) koppies in Limpopo at an altitude of approximately 700m. It coexists with mopane trees (Colophospermum mopane). They also occur in part of the Kruger National Park. Birds, monkeys and baboons disperse the Seeds. They consume the outer covering and the seeds are discarded/dispersed.
This tree is slow growing. Both male and female trees are necessary for seed production. In coastal and inland areas, this species prefers to be in full sun, but can tolerate some shade. For desert areas, this species should be placed in partial sun or filtered light. Plant in a well-drained position and avoid excessive moisture.
Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of Southern Africa, edn 3. Struik, Cape Town.