Gymnosperms

Abstract

Gymnosperms are a diverse group of plants with the common characteristic of having a ‘naked’, or unprotected, seed. (This contrasts with the other major seed‐bearing plant group, the angiosperms, whose seeds are enclosed in layers of tissue during development.) Historically common, today only approximately 1000 species exist worldwide. Four broad divisions (cycads, ginkgos, conifers and gnetophytes) are generally recognised. Gymnosperms are found in a wide variety of habitats, throughout most of the world. Many are trees: conifers are mostly evergreen trees with needle‐ or scale‐like leaves; cycads are palm‐like trees; ginkgos are deciduous, broad‐leaved trees and gnetophytes are mostly woody climbers (vines) or shrubs. The conifers are the most significant group of timber‐producing trees, and provide the majority of solid wood products worldwide. The economies of many countries depend on ‘softwood’ lumber derived from conifers.

Key Concepts:

  • Gymnosperms are plants with a ‘naked’, or unprotected, seed.

  • Gymnosperms live in a variety of habitats worldwide.

  • There are approximately 1000 species of gymnosperms alive today, in four broad divisions: cycads, ginkgos, conifers and gnetophytes.

  • Many gymnosperms are trees, and some are economically important as a source of timber and pulp.

  • Most gymnosperms are evergreen, woody perennials.

Keywords: conifers; cycads; ginkgo ; gnetophytes; gymnosperm

Figure 1.

Douglas fir (Pseudotsuga menziesii) – a majestic conifer of the Pacific coast of North America.

Figure 2.

Queen sago (Cycas circinalis). Reproduced from http://commons.wikimedia.org/wiki/File:Cycas_circinalis03.jpg.

Figure 3.

Maidenhair tree (G. biloba). Reproduced from http://upload.wikimedia.org/wikipedia/commons/1/1d/Ginkgo_Stamm.jpg.

Figure 4.

Welwitschia (W. mirabilis). Reproduced from http://upload.wikimedia.org/wikipedia/commons/3/3b/Welwitschia_mirabilis_S%26J7.jpg.

Figure 5.

Coast redwood (Sequoia sempervirens). Reproduced from http://upload.wikimedia.org/wikipedia/commons/d/d1/Corkskrewtree.jpg.

Figure 6.

Comparison of gymnosperm (Picea glauca) and angiosperm (rose family) flower and fruit morphology.

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Reference

Christenhusz MJM , Reveal JL , Farjon A et al. (2011) A new classification and linear sequence of extant gymnosperms. Phytotaxa 19: 55–70.

Further Reading

Beck CB (ed.) (1988) Origin and Evolution of Gymnosperms. New York: Columbia University Press.

Bond WJ (1989) The tortoise and the hare: ecology of angiosperm dominance and gymnosperm persistence. Biological Journal of the Linnean Society 36: 227–249.

Earle CJ (2013) The Gymnosperm Database. http://www.conifers.org

Enright NJ and Hill RS (eds) (1995) Ecology of the Southern Conifers. Washington, DC: Smithsonian Institution Press.

Farjon A (2010) A Handbook of the World's Conifers. Leiden/Boston: E.J. Brill.

Richardson DM (ed.) (1998) Ecology and Biogeography of Pinus. Cambridge: Cambridge University Press.

Royal Botanic Gardens and University of California (2013) Introduction to the Cycads. http://www.ucmp.berkeley.edu/seedplants/cycadophyta/cycads.html

Whitelock LM (2002) The Cycads. Portland, OR: Timber Press.

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How to Cite close
MacKinnon, Andy(Sep 2013) Gymnosperms. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0003680.pub2]