Gymnosperm

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Gymnosperm (Latin gymn-, “naked”; Greek sperma, “seed”), is a common name for any seed-bearing vascular plant without flowers. There are several types: the cycad, ginkgo, conifer, yew, and gnetophyte. Gymnosperms are woody plants, either shrubs, trees, or, rarely, vines (some gnetophytes). They differ from the other phylum of seed plants, the flowering plants (see Angiosperm), in that the seeds are not enclosed in carpels but rather are borne upon seed scales arranged in cones. The gymnosperms are the most ancient seed plants; they appear to have arisen from fern ancestors in the Devonian Period. Cycads retain the most primitive characters of the extant seed plants. Gnetophytes are considered from morphological and molecular evidence to share a common ancestry with the flowering plants. Living gymnosperms are distributed worldwide, with a majority, particularly the conifers, in temperate and subarctic regions. Cycads and gnetophytes are mainly tropical to subtropical. There are about 70 genera with 600 species of living gymnosperms, far less than many families of flowering plants.

Scientific classification: Gymnosperms are contained in four phyla: Cycadophyta, Ginkgophyta, Pinophyta, and Gnetophyta.


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