Cycad (Encephalartos hirsutus)

Description

Cycad fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Cycad description

Described as a new species in 1996, Encephalartos hirsutus is a Critically Endangered cycad from South Africa ^{(1) (2)}. The stems usually lie along the ground and terminate in a dense crown of rigid, glaucous leaves that become greyish with age. The emergent leaves are covered in dense hairs, which weather away at a much slower rate than in other cycads, hence the specific epithet hirsutus, which means "hairy” ^{(2) (4)}. Although woody in appearance, like all cycads, the stems are mostly comprised of soft, pithy storage tissue protected by a solid layer of old leaf bases ^{(4) (5)}. The reproductive organs of cycads take the form of cones, similar in appearance to those of a conifer ⁽⁶⁾, with the male and female cones being borne on separate plants ⁽⁴⁾. Male plants of E. hirsutus are known to produce up to five cones per stem, while female plants have been observed with just one to three cones on each stem ⁽²⁾. The cones are waxy bluish-green in colour, but while the female cones are distinctly egg-shaped, the male cones are relatively narrow ^(2) (5).

Size

Trunk length: up to 4.2 m ⁽²⁾

Trunk diameter: 35 - 40 cm ⁽²⁾

Cycad biology

Cycads are long-lived, slow growing plants that always occur as individual male or female plants ^{(4) (5)}. There is no way of determining the sex of a cycad until it begins to produce its first cone ⁽⁴⁾. 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 ^{(4) (5) (7)}. To attract pollinators, male and female cones produce powerful odours, usually in the early morning or evening ⁽⁴⁾. 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 ^{(4) (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 ⁽⁵⁾.

Cycad range

This recently described species is presently only known from three widely scattered localities in the Northern Province of South Africa ⁽²⁾.

Cycad habitat

Encephalartos hirsutus grows on southeast facing quartzite slopes amongst semi-deciduous mixed scrub ⁽²⁾.

Cycad status

Classified as Critically Endangered (CR) on the IUCN Red List ⁽¹⁾ and listed on Appendix I of CITES ⁽³⁾.

Cycad threats

Over the past few decades, many South African cycads have become increasingly scarce in the wild, with many species now facing the very real threat of extinction. Various factors account for their decline, but the main threats include illegal harvesting for horticulture, food and medicine, habitat loss, and the spread of alien vegetation ⁽⁹⁾. Although the threats to E. hirsutus are not well understood, with a population of less than 300 individuals, restricted to an extremely small range, this species is in significant danger of becoming extinct in the near future ^{(1) (9)}.

Cycad conservation

There are not known to be any specific conservation measures in place for this Critically Endangered species, but like all South African cycads, E. hirsutus is partially protected by its listing on Appendix I of CITES, which permits trade only under exceptional circumstances ⁽³⁾.

Find out more

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

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

Authentication

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

Glossary

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.

References

1. IUCN Red List (February, 2010)
   http://www.iucnredlist.org/
2. The Cycad Society of South Africa (February, 2010)
   http://www.cycadsociety.org/hirsutus/hirsutus.html#habitat
3. CITES (February, 2010)
   http://www.cites.org/
4. Whitelock, L.M. (2002) The Cycads. Timber Press, Portland, Oregon.
5. The Cycad Pages (February, 2010)
   http://plantnet.rbgsyd.nsw.gov.au/PlantNet/cycad/index.html
6. Royal Botanic Gardens, Kew (February, 2010)
   http://www.kew.org/plants/cycads/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.