Microcycas
Genus of cycads in the family Zamiaceae
title: "Microcycas" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["zamiaceae", "endemic-flora-of-cuba", "trees-of-cuba", "monotypic-gymnosperm-genera", "critically-endangered-flora-of-north-america", "plants-described-in-1868"] description: "Genus of cycads in the family Zamiaceae" topic_path: "general/zamiaceae" source: "https://en.wikipedia.org/wiki/Microcycas" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Genus of cycads in the family Zamiaceae ::
| status = CR | status_system = IUCN3.1 | status_ref = | status2 = CITES_A1 | status2_system = CITES | status2_ref = | image = Microcycas calocoma01.jpg | display_parents = 3 | grandparent_authority = D.W.Stev. | genus = Microcycas | parent_authority = A.DC. | species = calocoma | authority = (Miq.) A.DC., 1868 | synonyms_ref = | synonyms = Zamia calocoma Miq.
Microcycas is a genus of cycads in the family Zamiaceae containing only one species, Microcycas calocoma, endemic to a small area in western Cuba in Pinar del Río Province. It is estimated that there are 50-249 mature individuals left in the wild.
Description
The plant grows up to 10 m tall with an upright, sometimes branching trunk that grows to 30–60 cm in diameter. The leaves are dark green and 0.6–1.2 m long. One unique character is that the leaves appear to be truncated near the apex because the middle and distal leaflets have similar lengths. The petioles are 8–10 cm long and lack spines; the rachises also lack spines. leaflets are light to dark green, lanceolate, articulate at the base, and leathery with an entire margin. Middle leaflets are 15–25 cm long by 0.8–1 cm wide. Male cones are cylindrical, 25–30 cm long and 5–8 cm in diameter, yellow-brown, and hairy. Seed cones are broadly cylindrical, 50–90 cm long and 13–16 cm in diameter, yellow-brown, and hairy. The sporophylls have two round apical projections. The elliptical seeds are pink or red in color, 3.5–4 cm long and 2–2.5 cm in diameter. File:Microcycas calocoma 0zz.jpg|Plant File:Microcycas calocoma 3zz.jpg|Leaves File:Microcycas calocoma 4zz.jpg|Trunk File:Microcycas MaleDehiscentCone.jpg|Cone File:Microcycas calocoma 5zz.jpg|Trunk
Distribution
In its native range, Microcycas calocoma grows in small groups of 10–50 plants in montane forests at 85–250 m elevation. It also grows on the slopes of gullies and in open grassland and scrub at 50 m altitude. Soil types range from alkaline loam developed on limestone to acidic clays containing silica. In many of these groups of plants, however, the sex ratio is very unbalanced, resulting in a low output of seedlings. Humans have negatively impacted the species through forestry operations, clearing of land, and pesticide use. Because of the plant's graceful and ornamental appearance, harvesting of plants and seeds by growers has also seriously affected M. calocoma. Many populations are now protected in reserves.
Mutualism
The beetles Pharaxonotha esperanzae is in an obligatory mutualistic relationship with Microcycas calocoma, living and breeding in male cones and consuming pollen and cone tissues while serving as pollinating vectors by transferring pollen to female cones.
Conservation
The species is critically endangered, with a world population of only about 600 plants. It is listed under CITES Appendix I which prohibits international trade in specimens of this species except when the purpose of the import is not commercial, for instance for scientific research.
Although Microcycas calocomas round crown and shiny drooping leaves make it a very ornamental plant, cultivation is limited due to the lack of growing material. Locals have used the plant's toxic roots as a rat poison.
Threats
Habitat destruction and fragmentation have a moderate impact on the plants, along with the issue of over-collecting them from their natural environment. There is also a potential concern about reproductive failure due to the extinction of pollinators, although further verification is required to confirm this.
References
- Jones, David L. Cycads of the World: Ancient Plants in Today's Landscape. Washington, D.C.: Smithsonian Institution Press, 2002. .
- Microcycas calocoma in The Cycad Pages
References
- "Appendices {{!}} CITES".
- [http://apps.kew.org/wcsp/synonomy.do?name_id=379228 Kew World Checklist of Selected Plant Families]
- "Redlist article about Microcycas".
- (September 2005). "A new species of ''Pharaxonotha'' (Coleoptera: Erotylidae), probable pollinator of the endangered Cuban cycad, ''Microcycas calocoma'' (Zamiaceae)". Insecta Mundi.
- Donaldson, J.S. 2003. [http://www.iucnredlist.org/search/details.php/42107/summ ''Microcycas calocoma'' in the IUCN Red List of Threatened Species]. Downloaded on November 2006.
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