Eastern Cape giant cycad (Encephalartos altensteinii)
| Also known as: | Hottentot bread tree |
|---|
| Kingdom | Plantae |
|---|---|
| Phylum | Tracheophyta |
| Class | Cycadopsida |
| Order | Cycadales |
| Family | Zamiaceae |
| Genus | Encephalartos (1) |
| Size | Max height: 4-5 m (2) |
Classified as Vulnerable (VU) on the IUCN Red List (1) and listed on Appendix I of CITES (3).
In a conservatory at Kew Royal Botanic Gardens lives one of world’s oldest pot plants, an Eastern Cape giant cycad collected in South Africa in the early 1770s (4). This popular ornamental species has a tall, stout stem, topped with a dense, upright crown of bright-green palm-like leaves up to 2.5 metres in length (2). Although woody in appearance, the stem is mostly comprised of soft, pithy storage tissue protected by a solid layer of old leaf bases (5) (6). Initially, the single stem is erect, but over time it usually begins to recline at an angle, and may sucker from the base to form a clump of multiple stems (2) (5). The sexes are borne on separate plants, as indicated at reproductive maturity by the presence of two to five male or female cones on each stem (5) (6). The large, yellowish green female cones are egg-shaped, almost resembling a pineapple, while the similarly coloured, but smaller, male cones are cylindrical (2) (5).
The Eastern Cape giant cycad is widely distributed in the Eastern Cape and south-western KwaZulu-Natal, South Africa (1).
Found near the coast in habitat ranging from open shrubland on steep rocky slopes to closed evergreen forest in valleys (1).
Cycads are long-lived, slow-growing plants that bear their reproductive organs in cones on separate plants, with male cycads bearing cones that contain pollen, and female cycads producing cones that contain ovules that later become seeds (4) (5) (6). There is no way of determining the sex of a cycad until it begins to produce its first cone (6). For a long time cycads were thought, like cone-producing conifers, to be entirely wind pollinated (7). However, studies now suggest that the vast majority, if not all cycads, are actually pollinated by insects or more specifically weevils (5) (6) (7). To attract pollinators, male and female cones produce powerful odours, usually in the early morning or evening (6). Travelling between the sexes, the weevils pollinate the plants by inadvertently transferring pollen from the male cones to the receptive ovules of the female cones (6) (8).
The seeds produced by cycads are large and have a fleshy outer coat, but are relatively short-lived and vulnerable to desiccation (5). The fleshy red seeds of the Eastern Cape giant cycad are known to attract the Knysna turaco and trumpeter hornbill (9). Consuming the seeds, the birds digest the outer coat but subsequently regurgitate the unpalatable seed. If the seeds are discarded in a hospitable environment, there is a relatively good chance they will germinate and grow into a mature plant (5) (9).
Although land clearance has claimed hundreds of Eastern Cape giant cycads, and numerous plants have been taken from the wild to sustain nurseries, this species remains common throughout its range (6).
There are no specific conservation measures in place for the Eastern Cape giant cycad, but it is listed on Appendix I of CITES, which permits trade only under exceptional circumstances (3).
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact: arkive@wildscreen.org.uk
- Germinate: the beginning of growth, usually following a period of dormancy and in response to favourable conditions. For example, the sprouting of a seedling from a seed.
- Ovules: a structure within the female reproductive organs of plants that contains eggs and when fertilized by pollen, develops into seeds
- Pollinate: to transfer pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.
- Pollinators: animals that in the act of visiting a plant’s flowers transfer pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant
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IUCN Red List (December, 2008)
http://www.iucnredlist.org/ - Royal Botanic Gardens Kew. (2009) Pers. comm.
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CITES (December, 2008)
http://www.cites.org -
Royal Botanic Gardens, Kew (March, 2009)
http://www.kew.org/plants/cycads/index.html -
The Cycad Pages (November, 2008)
http://plantnet.rbgsyd.nsw.gov.au/PlantNet/cycad/index.html - Whitelock, L.M. (2002) The Cycads. Timber Press, Portland, Oregon.
- Jolivet, P. (2005) Cycads and beetles: recent views on pollination. The Cycad Newsletter, 28: 3 - 7.
- Donaldson, J.S. (1997) Is there a floral parasite mutualism in cycad pollination? The pollination biology of Encephalartos villosus (Zamiaceae). American Journal of Botany, 84: 1398 - 1406.
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PlantZAfrica (March, 2009)
http://www.plantzafrica.com/plantefg/encephalten.htm