Cycadophyta

Cycadophyta is a division of seed plants that includes a single extant family, Cycadaceae, and several extinct families. The group is unique among seed plants in having motile sperm.

Description

Cycads are gymnosperms (naked seeded), with large compound leaves and a stout trunk. They are frequently confused with and mistaken for palms or ferns, but are related to neither, belonging to the division Cycadophyta. They typically have a stout and woody (ligneous) trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves.

Taxonomy

The living cycads are often regarded as a relict group, being the sole survivors of a large and diverse group that was much more abundant and diverse in the Mesozoic era. All the cycads are tropical or subtropical and each species has a very small range, often being confined to a small part of an island or a mainland area.

Distribution and habitat

Cycads are found across much of the subtropical and tropical parts of the world. They are found in South and Central America (where the greatest diversity occurs), Mexico, the Antilles, southeastern United States, Australia, Melanesia, Micronesia, Japan, China, Southeast Asia, India, Sri Lanka, Madagascar, and southern and tropical Africa, where at least 65 species occur.

Uses

Some plants in the Cycadophyta division are used for food, ornamental plants, and in traditional medicine.

Conservation

Many cycads are on the verge of extinction in the wild due to habitat destruction and over-collecting for use in horticulture. Several species are legally protected from all collecting without a permit.

See also

• Cycadaceae
• Gymnosperms
• Mesozoic era
• Horticulture

References

Cycadophyta Resources
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