Gymnosperm

Gymnosperms are a group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes. The term "gymnosperm" comes from the Greek composite word γυμνόσπερμος (γυμνός, 'naked' and σπέρμα, 'seed'), as the ovules and subsequent seeds are not enclosed in a protective structure (carpels or fruit), but are borne naked, typically on cone scales.

Classification

The gymnosperms are divided into four divisions:

• Cycadophyta (cycads)
• Ginkgophyta (ginkgo)
• Pinophyta (conifers)
• Gnetophyta (gnetophytes)

Characteristics

Gymnosperms are characterized by the following features:

• They are vascular plants with roots, stems, and leaves.
• They produce seeds that are not enclosed within an ovary or fruit.
• They have a life cycle that involves alternation of generations.
• Most gymnosperms are evergreen, retaining their leaves throughout the year.

Reproduction

Gymnosperms reproduce by means of an exposed seed that develops from a fertilized ovule. Unlike angiosperms, gymnosperms do not produce flowers or fruit, and their seeds are often formed in cones.

Economic Importance

Gymnosperms have economic importance. Conifers, for example, are used for timber, and the ginkgo tree is used in traditional medicine.

See Also

• Angiosperms
• Seed
• Plant reproduction
• Conifers
• Cycads
• Ginkgo
• Gnetophytes

References

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Gymnosperm

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  Gymnospermae
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  Encephalartos sclavoi reproductive cone
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  Zamia integrifolia
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  Gymnosperm life cycle