☀☀✌✌❄❄☀☀❤gymnosperm ncert with full detail✴✴✴✴✴✴
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Gymnosperms are a group of plants which produce seeds that are not contained within an ovary or fruit. The seeds are open to the air and are directlyfertilized by pollination.
“Gymnosperm”, from the Greek, gymnos, “naked” and sperma, “seed”, develop their seeds on the surface of scales and leaves, which often grow to form cone or stalk shapes, contrasting in characteristics from theangiosperms, flowering plants which enclose their seeds within an ovary.
The gymnosperms consist of the conifers, the cycads, the gnetophytes and the sole extant species of theGynkgophyta division, the Gingko biloba.
“Gymnosperm”, from the Greek, gymnos, “naked” and sperma, “seed”, develop their seeds on the surface of scales and leaves, which often grow to form cone or stalk shapes, contrasting in characteristics from theangiosperms, flowering plants which enclose their seeds within an ovary.
The gymnosperms consist of the conifers, the cycads, the gnetophytes and the sole extant species of theGynkgophyta division, the Gingko biloba.
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The gymnosperms are a group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes. The term "gymnosperm" comes from the Greek composite word γυμνόσπερμος (γυμνός gymnos, "naked" and σπέρμα sperma, "seed"), meaning "naked seeds". The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds stands in contrast to the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in Yew, Torreya, Ginkgo.[1]
Gymnospermae
Temporal range: Carboniferous - Present
PreЄЄOSDCPTJKPgN
Various gymnosperms.
Scientific classification
Kingdom:
Plantae
Subkingdom:
Embryophyta
(unranked):
Gymnospermae (paraphyletic)
Divisions
Pinophyta (or Coniferophyta) - Conifers
Ginkgophyta - Ginkgo
Cycadophyta - Cycads
Gnetophyta - Gnetum, Ephedra, Welwitschia
Encephalartos sclavoi cone, about 30 cm long
The gymnosperms and angiosperms together compose the spermatophytes or seed plants. The gymnosperms are divided into six phyla. Organisms that belong to the Cycadophyta, Ginkgophyta, Gnetophyta, and Pinophyta (also known as Coniferophyta) phyla are still in existence while those in the Pteridospermales and Cordaitales phyla are now extinct.[2]
By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes (Gnetum, Ephedra and Welwitschia), and Ginkgo biloba (a single living species).
Roots in some genera have fungal association with roots in the form of mycorrhiza (Pinus), while in some others (Cycas) small specialised roots called coralloid roots are associated with nitrogen-fixing cyanobacteria.
For the most recent classification on extant gymnosperms see Christenhusz et al. (2011).[6] There are 12 families, 83 known genera with a total of ca 1080 known species (Christenhusz & Byng 2016 [7]).
Subclass Cycadidae
Order Cycadales
Family Cycadaceae: Cycas
Family Zamiaceae: Dioon, Bowenia, Macrozamia, Lepidozamia, Encephalartos, Stangeria, Ceratozamia, Microcycas, Zamia.
Subclass Ginkgoidae
Order Ginkgoales
Family Ginkgoaceae: Ginkgo
Subclass Gnetidae
Order Welwitschiales
Family Welwitschiaceae: Welwitschia
Order Gnetales
Family Gnetaceae: Gnetum
Order Ephedrales
Family Ephedraceae: Ephedra
Subclass Pinidae
Order Pinales
Family Pinaceae: Cedrus, Pinus, Cathaya, Picea, Pseudotsuga, Larix, Pseudolarix, Tsuga, Nothotsuga, Keteleeria, Abies
Order Araucariales
Family Araucariaceae: Araucaria, Wollemia, Agathis
Family Podocarpaceae: Phyllocladus, Lepidothamnus, Prumnopitys, Sundacarpus, Halocarpus, Parasitaxus, Lagarostrobos, Manoao, Saxegothaea, Microcachrys, Pherosphaera, Acmopyle, Dacrycarpus, Dacrydium, Falcatifolium, Retrophyllum, Nageia, Afrocarpus, Podocarpus
Order Cupressales
Family Sciadopityaceae: Sciadopitys
Family Cupressaceae: Cunninghamia, Taiwania, Athrotaxis, Metasequoia, Sequoia, Sequoiadendron, Cryptomeria, Glyptostrobus, Taxodium, Papuacedrus, Austrocedrus, Libocedrus, Pilgerodendron, Widdringtonia, Diselma, Fitzroya, Callitris (incl. Actinostrobus and Neocallitropsis), Thujopsis, Thuja, Fokienia, Chamaecyparis, Callitropsis, Cupressus, Juniperus, Xanthocyparis, Calocedrus, Tetraclinis, Platycladus, Microbiota
Family Taxaceae: Austrotaxus, Pseudotaxus, Taxus, Cephalotaxus, Amentotaxus, Torreya.
Gymnospermae
Temporal range: Carboniferous - Present
PreЄЄOSDCPTJKPgN
Various gymnosperms.
Scientific classification
Kingdom:
Plantae
Subkingdom:
Embryophyta
(unranked):
Gymnospermae (paraphyletic)
Divisions
Pinophyta (or Coniferophyta) - Conifers
Ginkgophyta - Ginkgo
Cycadophyta - Cycads
Gnetophyta - Gnetum, Ephedra, Welwitschia
Encephalartos sclavoi cone, about 30 cm long
The gymnosperms and angiosperms together compose the spermatophytes or seed plants. The gymnosperms are divided into six phyla. Organisms that belong to the Cycadophyta, Ginkgophyta, Gnetophyta, and Pinophyta (also known as Coniferophyta) phyla are still in existence while those in the Pteridospermales and Cordaitales phyla are now extinct.[2]
By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes (Gnetum, Ephedra and Welwitschia), and Ginkgo biloba (a single living species).
Roots in some genera have fungal association with roots in the form of mycorrhiza (Pinus), while in some others (Cycas) small specialised roots called coralloid roots are associated with nitrogen-fixing cyanobacteria.
For the most recent classification on extant gymnosperms see Christenhusz et al. (2011).[6] There are 12 families, 83 known genera with a total of ca 1080 known species (Christenhusz & Byng 2016 [7]).
Subclass Cycadidae
Order Cycadales
Family Cycadaceae: Cycas
Family Zamiaceae: Dioon, Bowenia, Macrozamia, Lepidozamia, Encephalartos, Stangeria, Ceratozamia, Microcycas, Zamia.
Subclass Ginkgoidae
Order Ginkgoales
Family Ginkgoaceae: Ginkgo
Subclass Gnetidae
Order Welwitschiales
Family Welwitschiaceae: Welwitschia
Order Gnetales
Family Gnetaceae: Gnetum
Order Ephedrales
Family Ephedraceae: Ephedra
Subclass Pinidae
Order Pinales
Family Pinaceae: Cedrus, Pinus, Cathaya, Picea, Pseudotsuga, Larix, Pseudolarix, Tsuga, Nothotsuga, Keteleeria, Abies
Order Araucariales
Family Araucariaceae: Araucaria, Wollemia, Agathis
Family Podocarpaceae: Phyllocladus, Lepidothamnus, Prumnopitys, Sundacarpus, Halocarpus, Parasitaxus, Lagarostrobos, Manoao, Saxegothaea, Microcachrys, Pherosphaera, Acmopyle, Dacrycarpus, Dacrydium, Falcatifolium, Retrophyllum, Nageia, Afrocarpus, Podocarpus
Order Cupressales
Family Sciadopityaceae: Sciadopitys
Family Cupressaceae: Cunninghamia, Taiwania, Athrotaxis, Metasequoia, Sequoia, Sequoiadendron, Cryptomeria, Glyptostrobus, Taxodium, Papuacedrus, Austrocedrus, Libocedrus, Pilgerodendron, Widdringtonia, Diselma, Fitzroya, Callitris (incl. Actinostrobus and Neocallitropsis), Thujopsis, Thuja, Fokienia, Chamaecyparis, Callitropsis, Cupressus, Juniperus, Xanthocyparis, Calocedrus, Tetraclinis, Platycladus, Microbiota
Family Taxaceae: Austrotaxus, Pseudotaxus, Taxus, Cephalotaxus, Amentotaxus, Torreya.
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