This endangered Cycad is up to 3,5m high. Leaves are pinnately compound. Dioecious Cones: Female cones are up to 60 x 16cm. The fleshy Testa (seed coat) is yellow.
Encephalartos kisambo, E. voiensis.
RSA Tree No. n/a: Not found in the RSA.
Common name: Voi cycad.
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. kisambo – from the local Taita language (within Kenya). 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. 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. Endangered. 2003. According to http://www.iucnredlist.org/details/41906/0. These trees are only found in 4 locations and may become Critically Endangered in the near future. This cycad is threatened by over collection, habitat loss and are removed when other trees are collected for charcoal production.
Description. This Tree may reach 3,5m high but is usually smaller, especially in the open. The trunk, which tends to taper towards the end, may have a diameter slightly in excess of 0,5m. It also develops a large taproot. Swollen leaf bases are present that are not grooved. The leaves leave scars when they fall.
Cycads are unique Gymnosperms with pinnately compound (leaflets arranged along either side of the leaf rachis, central stalk, like a feather.) Leaves. Leaves are pungent, long and upright reaching 3,5m in length. They are semi-glossy and pinnately compound (leaflets arranged along either side of leaf rachis – a central stalk), have a gradually narrowing base and are oblong with a rounded apex. Leaflets are lanceolate, coriaceous and up to 35cm long and are more widely spaced when the tree grown in shady places.
Cones are produced on this dioecious (having male and female parts on separate plants) tree. Up to 6 yellow Male cones are often produced annually. They may reach 60cm in length and up to 11cm in diameter. Female cones take about 12 months to develop and may only appear every other year. They may reach 60cm long and 16cm in diameter. The fleshy Testa (seed coat) is yellow.
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 extanct (not extinct) species of Ginkgo (Ginkgo biloba), the male cones produce motile sperms. Whereas, 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
This Cycad is located in Kenya and Tanzania and is found in misty rain forests or in dried mountainside up to an elevation of between 800 and 1 800m. In its natural area, it may be home to a number of epiphytic plants, including Orchids. Compared to the cycad norm, this plant is relatively fast growing.
These plants should be planted in light shade, preferably out of a frost environment. Suckering is infrequent. The Seeds may be poisonous.