Cycad (Cycas clivicola)

Species information

Facts

Kingdom	Plantae
Phylum	Tracheophyta
Class	Cycadopsida
Order	Cycadales
Family	Cycadaceae
Genus	Cycas (1)
Size	Height: up to 8 m (2) Leaf length: 70 – 165 cm (2) Pollen cone length: 25 – 50 cm (2)

Status

This cycad is classified as Near Threatened (NT) on the IUCN Red List 2004 (1) and is listed on Appendix II of CITES (3).

Description

Cycads have large, divided leaves and resemble palms and tree ferns superficially. This cycad species has a tall, narrow trunk with very long, slightly glossy leaves varying in colour with age from grey-green when young to bright green once mature. The large pollen cones vary from yellow through green to brown. There are two subspecies of this cycad that differ in appearance. Cycas clivicola clivicola has a smooth, grey trunk and relatively small pollen cones, whereas Cycas clivicola lutea has a smooth, yellow trunk and larger pollen cones (2).

Range

Found in Malaysia and southern Thailand (4).

Habitat

As indicated by the Latin name of this species, ‘clivicola', it is a cliff-dweller. It grows in the crevices of limestone outcrops, in full sun (2).

Biology

Cycads are dioecious, with separate male and female individuals. Large seeds with a fleshy coating and a hard centre are produced on the leaves. These are dispersed to nearby soil by birds, rodents and fruit bats, where they must germinate quickly to survive. If conditions are not suitable for germination, the seeds cannot lie dormant, and so will perish. Cycads are long-lived, slow-growing, and have a low reproductive rate. Their roots contain cyanobacteria that exist in a symbiotic relationship with the plant, and provide it with further nutrients by converting (fixing) atmospheric nitrogen into a usable form. The roots are also retractable for protection against drought and fire (2).

Threats

In some areas this cycad species is threatened by over-collection, but in general it is widespread and abundant (2).

Conservation

Cycad conservation is important to many sectors. They are an important group in horticulture, as well as being an ancient plant taxon. They contribute to the health and fertility of soil through their relationship with nitrogen fixing bacteria, and they are of interest to the pharmaceutical industry due to unique compounds contained within them (2). There is no targeted conservation action for this species.

Further Information

For further information on cycads see the Palm and Cycad Societies of Australia website:
http://www.pacsoa.org.au/cycads/Cycas/clivicola.html

Authentication

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Glossary

Cyanobacteria: A group of bacteria that are able to photosynthesise and contain the pigment chlorophyll. They used to be known as ‘blue-green algae'. They are thought to have been the first organisms to produce oxygen; fossil cyanobacteria have been found in 3000 million year old rocks. As they are responsible for the oxygen in the atmosphere they have played an essential role in influencing the course of evolution on this planet.
Dioecious: Male and female flowers are borne on separate plants.
Subspecies: A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
Symbiotic relationship: Relationship in which two organisms form a close association, the term is now usually used only for associations that benefit both organisms (a mutualism).