Turk's head cactus (Melocactus intortus)

Description

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Turk's head cactus fact file

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

Turk's head cactus description

The Turk’s head cactus (Melocactus intortus) is an unusual and bizarre-looking succulent plant, characterised by its large, spherical green stem from which a bristly cylindrical cap, called a cephalium, develops ^{(2) (5) (6)}. The rounded, pale green stem is the photosynthetic body, produced when the plant is young ^{(6) (7)}. Up to 20 large, broad ribs run up the length of the stem, and it is covered in stout, yellow-brown spines which may measure up to 7 centimetres ^{(2) (5) (6)}. Often there is a distinct central spine which is surrounded by radial spines, resembling an asterisk ⁽⁶⁾.

The cephalium is produced when the Turk’s head cactus reaches maturity, and continues to grow until the plant dies. It is a dense mass of areoles, made up of white wool and soft brown or reddish bristles ^{(2) (5) (6)}. The small, generally pinkish flowers form on top of the cephalium. The conspicuous fruits of the Turk’s head cactus are broad and club-shaped, and are usually red or pink ^{(2) (5) (6)}.  

The Turks Islands in the Caribbean take their name from the Turk’s head cactus, which is widespread throughout the islands. The name of the plant itself comes from its spiny red cap, which is thought to resemble a fez (a short, cylindrical red hat) ^{(5) (8)}.

Size

Height: up to 1 m ⁽²⁾

Diameter: 15 - 40 cm ⁽²⁾

Turk's head cactus biology

Very little specific information is available on the biology of the Turk’s head cactus.

In general, cacti have evolved to cope with hot, arid environments. The thick, succulent stems have a large volume to store food and water, and are usually covered in a thick, waxy layer which helps to prevent water loss ⁽¹⁰⁾. The spines present on most cacti are essentially modified leaves, which grow from a unique, specialised structure called an areole. The areole is a sunken cushion of tissue which has two buds (growing points), with spines developing on one, and flowers and fruit on the other ^{(10) (11) (12)}.

The spines of cacti protect the plant from grazing animals, and light-coloured or woolly spines reflect the sunlight, preventing damage from the sun’s radiation. Water also accumulates on the spines of cacti during the night or when it rains, and is then directed down the stem to the roots. The spines of different cactus species vary widely in their shape and size, and may even be hooked, curved or barbed ^{(10) (11)}. Some cacti may be spineless ^{(10) (12)}. The roots of cacti are generally shallow and widespread, allowing them to exploit temporary water sources at the surface. Many species have taproots that go deep into the soil, anchoring the plant and enabling it to obtain additional water and nutrients ⁽¹⁰⁾.

Turk's head cactus range

The Turk’s head cactus occurs throughout the Caribbean, including the Antilles, Puerto Rico and the U.S. Virgin Islands, the Bahamas and the Turks and Caicos Islands, and Antigua and Barbuda ^{(2) (4) (5) (9)}.

Turk's head cactus habitat

The Turk’s head cactus appears to grow in wide variety of habitats throughout its range, although none have been specifically described.

Turk's head cactus status

The Turk’s head cactus has yet to be assessed by the IUCN. It is listed on Appendix II of CITES ⁽³⁾ and is considered Endangered (EN) on the Red List of Vascular Plants of Antigua and Barbuda ⁽⁴⁾.

Turk's head cactus threats

The Turk’s head cactus has been heavily collected from the wild, particularly in Puerto Rico, St. Eustatius and Grenada ⁽⁹⁾.

Turk's head cactus conservation

The Turk’s head cactus is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that all trade in this species requires careful monitoring ⁽³⁾. It is included on Annex III of the Protocol on Specially Protected Areas and Wildlife (SPAW), which regulates the exploitation of this cactus as a harvestable species according to management plans. The Turk’s head cactus is also among a number of species that are proposed for inclusion on a schedule of protected species in Antigua and Barbuda legislation ⁽⁴⁾.

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Find out more

Find out more about cactus conservation:

• Oldfield, S. (1997) Cactus and Succulent Plants - Status Survey and Conservation Action Plan. IUCN/SSC Cactus and Succulent Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK. Available at:
  http://data.iucn.org/dbtw-wpd/edocs/1997-041.pdf

 Find out more about plant conservation:

• Royal Botanic Gardens, Kew:
  http://www.kew.org/

 Find out more about conservation in the Turks and Caicos Islands and other UK Overseas Territories:

• UK Overseas Territories Conservation Forum:
  http://www.ukotcf.org/

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Glossary

Areole

In cacti, the felted or woolly, cushion-like structures from which spines grow, flowers develop and new stems arise.

Photosynthetic

Capable of photosynthesis, a metabolic process characteristic of plants in which carbon dioxide is broken down, using energy from sunlight absorbed by the green pigment chlorophyll. Organic compounds are made and oxygen is given off as a by-product.

References

1. UNEP-WCMC (February, 2011)
   http://www.unep-wcmc.org/
2. Anderson, E.F. (2001) The Cactus Family. Timber Press, Portland, Oregon and Cambridge, UK.
3. CITES (February, 2011)
   http://www.cites.org/
4. Pratt, C. and Lindsay, K. (2008). Red List of vascular plants of Antigua and Barbuda. Environmental Awareness Group of Antigua & Barbuda, 4:1-24.
5. Britton, N.L. and Rose, J.N. (1963) The Cactaceae. Dover Publications, New York.
6. Cacti Guide - Melocactus (February, 2011)
   http://cactiguide.com/cactus/?genus=Melocactus
7. Mauseth Research: Cacti - Melocactus intortus (February, 2011)
   http://www.sbs.utexas.edu/mauseth/researchoncacti/large%20photo%20Melo%20intortus%20ceph.htm
8. Royal Botanic Gardens, Kew: UK Overseas Territories Programme (February, 2011)
   http://www.kew.org/science/ukots/Pages/tci2ai.htm
9. Oldfield, S. (1997) Cactus and Succulent Plants - Status Survey and Conservation Action Plan. IUCN/SSC Cactus and Succulent Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK. Available at:
   http://data.iucn.org/dbtw-wpd/edocs/1997-041.pdf
10. Dalhousie Collection of Cacti and other Succulents: Biology of Cacti (February, 2011)
    http://cactus.biology.dal.ca/biology.html
11. Cactus and Succulent Society of New Zealand (February, 2011)
    http://www.cssnz.org/
12. Heywood, V.H. (1978) Flowering Plants of the World. Oxford University Press, Oxford.