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Gymnosperms- Chapter 18
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Naked versus Enclosed Seed Plants Gymnosperms –Gymno- gr. naked. –Sperma- gr. seed. Angiosperms –Angeion- gr. vessel. –Sperma- gr. seed.
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Extant Gymnosperms Match the common name on the right to the phylum on the left. –1) Cycadophyta a. ginkgo –2) Ginkgophytab. conifers –3) Coniferophyta c. cycads –4) Gnetophyta d. gnetophytes
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Cycadophyta Cycas- gr. palm. Tracheids, but no vessel elements. Sperm present, multiflagellated. Palmlike leaves. Pollen tube does not fuse with the egg cell. Ovulate (megasporangiate) & microsporangiate cones simple & on separate plants. 11 genera & 140 species. Examples- Cycas & Zamia. Zamia
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Cycas
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Ginkgophyta Yin- ch. silver, hing- ch. apricot. Tracheids, but no vessel elements. Sperm present, multiflagellated. Fan-shaped leaves. Pollen tube does not fuse with the egg cell. Ovulate & microsporangiate cones on separate plants; fleshy-coated seeds. 1 genus & 1 species. Examples- Gingko biloba= maidenhair tree.
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Coniferophyta Con- gr. cone, fer- L. bear. Tracheids, but no vessel elements. Sperm not motile. Needlelike or scalelike leaves. Pollen tube fuses with egg cell. Ovulate & microsporangiate cones on same plant; ovulate cones compound. 70 genera & 630 species. Examples- Pinus, Picea, Juniperus, Abies, Cupressus.
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True or False. These winglike structures are female pollen grains.-------------------------->
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Pinus- pine (Pinaceae).
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Metasequoia- Dawn redwood.
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Wollemia nobilis- Wollemi pine.
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Gnetophyta Gneto- Malay gnenom. Tracheids and vessel elements. Sperm not motile. Scalelike, leaflike, broad and leathery leaves. Pollen tube fuses with egg cell. Ovulate & microsporangiate cones compound & mostly borne on separate plants. 3 genera & 70 species. Examples- Gnetum, Ephedra, Welwitschia.
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Gnetum
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Ephedra
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Welwitschia
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