Gymnosperms - 2 dictionary results
gym·no·sperm
 (jĭm'nə-spûrm') Pronunciation Key
n. A plant, such as a cycad or conifer, whose seeds are not enclosed within an ovary. [From New Latin Gymnospermae, class name, from Greek gumnospermos : gumnos, naked; see nogw- in Indo-European roots + sperma, seed; see sperm1.] gym'no·sper'mous adj., gym'no·sper'my n. |
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2006 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Copyright © 2006 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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| gymnosperm
(jĭm'nə-spûrm') Pronunciation Key
Any of a group of seed-bearing plants whose ovules are not enclosed in an ovary, but are exposed on the surface of sporophylls or similar structures. Each ovule may contain several eggs, all of which may be fertilized and start to develop in a process known as polyembryony. In most seeds, however, only a single embryo survives. The reproductive structures of many gymnosperms are arranged in cones. The gymnosperms do not form a distinct monophyletic grouping, but simply include all the seed-bearing plants that are not angiosperms. In addition to several extinct groups, there are four very diverse living gymnosperm phyla: the conifers, the cycads, the ginkgo (surviving in a single species), and the gnetophytes. Compare angiosperm. See more at seed-bearing plant.
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The American Heritage® Science Dictionary
Copyright © 2002 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Copyright © 2002 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source
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