Where are seeds of jymnosperm form
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"Gymnosperms" include all seed plants other than the angiosperms, or flowering plants. The absence of an enclosing structure is believed to be primitive, thus the first seed plants were "gymnosperms." The seeds of "gymnosperms" are borne exposed in open structures, such as cones or leaves. The derivation of the word "gymnosperm" means naked seeds and is from the Greek words
gymno meaning naked or bare and sperm meaning seed. Fossil records indicate "gymnosperms" originated in the Paleozoic Era, during the middle Devonian Period about 390 million years ago, and reached their greatest diversity during the Mesozoic Era, between 60 to 225 million years ago. Although the "gymnosperms" were at one time treated as one closely allied group, many modern workers recognize several major groups, which include the commonly known conifers, cycads, and ginkgos, and the lesser known gnetopsids group, extinct progymnosperms, and extinct seed ferns.
gymno meaning naked or bare and sperm meaning seed. Fossil records indicate "gymnosperms" originated in the Paleozoic Era, during the middle Devonian Period about 390 million years ago, and reached their greatest diversity during the Mesozoic Era, between 60 to 225 million years ago. Although the "gymnosperms" were at one time treated as one closely allied group, many modern workers recognize several major groups, which include the commonly known conifers, cycads, and ginkgos, and the lesser known gnetopsids group, extinct progymnosperms, and extinct seed ferns.
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"Gymnosperms" are a diverse and paraphyletic group of seed plants, and can be characterized by the following features: exposed seeds formed in cones, pollination occurring by pollen landing directly on the ovules, generally one fertilization event in the ovules, and tracheids as the water-conducting cells (xylem)
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