Bushman’s River cycad (Encephalartos trispinosus)

A small, clumped species, the Bushman’s River cycad typically branches from the base, with mature plants developing as many as four to six stems ^{(2) (4) (5)}. Despite their woody appearance, like all cycads, the stems are mainly comprised of soft, pithy storage tissue protected by a hard layer of old leaf bases ^{(2) (6)}. The greenish-grey to blue leaves are numerous and spreading, with the tips curving backwards and downwards. The specific name of the Bushman’s River cycad, trispinosus, derives from the Latin words for ‘three’ and ‘spiny’, and refers to the leaflets, which typically consist of three lobes with a spine at each point ^{(2) (4)}. Mature female plants produce a solitary, bright-yellow, egg-shaped cone on each stem, while the cones of male plants are more cigar-shaped and occasionally grow two to a stem ^{(2) (4) (6)}.

Size

Height: up to 1 m ⁽²⁾

Cycads are long-lived, slow growing plants that always occur as individual male or female plants ^{(2) (6)}. There is no way of determining the sex of a cycad until it begins to produce its first cone ⁽²⁾. 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 ^{(2) (6) (7)}. To attract pollinators, male and female cones produce powerful odours, usually in the early morning or evening ⁽²⁾. 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 ^{(2) (8)}.

The seeds produced by cycads are large and have a fleshy outer coat, but are relatively short-lived and vulnerable to desiccation. The fleshy outer layer is desirable to a range of animals such as birds, rodents and bats, depending on the species of cycad and region it occupies. However, with any luck the unpalatable seed is discarded some distance away from the parent plant in a hospitable environment in which to germinate ⁽⁶⁾.

Endemic to South Africa, where it occurs in the valleys of the Bushman’s River and the Great Fish River in the Eastern Cape ^{(1) (4)}.

Grows on rocky slopes and ridges in arid, low, succulent shrubland ⁽¹⁾

Classified as Vulnerable (VU) on the IUCN Red List ⁽¹⁾ and listed on Appendix I of CITES ⁽³⁾.

Like many South African cycads, the Bushman’s River cycad is declining due to over-collection and habitat loss ⁽⁹⁾.

There are not known to be any specific conservation measures in place for the Bushman’s River cycad, but it is listed on Appendix I of CITES, which permits trade only under exceptional circumstances ⁽³⁾.

For further information on the conservation of cycads in South Africa see:

• The Cycad Society of South Africa:
  www.cycadsociety.org
• South African National Biodiversity Institute:
  www.sanbi.org
• IUCN/SSC Cycad Specialist Group:
  www.cycadsg.org

Endemic

A species or taxonomic group that is only found in one particular country or geographic area.

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

1. IUCN Red List (October, 2009)
   http://www.iucnredlist.org/
2. Whitelock, L.M. (2002) The Cycads. Timber Press, Portland, Oregon.
3. CITES (October, 2009)
   http://www.cites.org
4. PlantZAfrica (October, 2009)
   http://www.plantzafrica.com/plantefg/encepharenarius.htm
5. Palm and Cycad Societies of Australia (PACSOA) (October, 2009)
   http://www.pacsoa.org.au/cycads/Encephalartos/trispinosus.html
6. The Cycad Pages (October, 2009)
   http://plantnet.rbgsyd.nsw.gov.au/PlantNet/cycad/index.html
7. Jolivet, P. (2005) Cycads and beetles: recent views on pollination. The Cycad Newsletter, 28: 3 - 7.
8. 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.
9. Donaldson, J.S. (2003) Cycads, status survey and conservation action plan. IUCN/SSC-Cycad Specialist Group. IUCN, Gland, Switzerland.