Seed fern Gang (pteridospermopsida) The original extinct gymnosperms. May have originated in the former gymnosperms, beginning now in the Late Devonian, Carboniferous, Permian heyday, Mesozoic gradually decline, extinct in the Cretaceous. Plant seed ferns are generally small, most of the students are leaning or climbing this type. Also part of the upright tree fern-like, unbranched, up to 10 meters, or erect stout small tree. The vast majority of seed fern plants like ferns with large fern leaf (mostly pinnate) and pulse sequence, the difference is in the type of reproductive fern leaf length seeds and pollen sacs, often the main two fern leaf petiole bifurcations, cuticle thick leaf surface. Anatomy of stems and roots of ferns Gang is both traits and traits with gymnosperms, a native of columns, column or really where the body of the column. There marrow stem pith often large, thick cortex and secondary vascular tissue thin, sparse wood type secondary xylem anatomy and 苏铁纲 their most similar, never found before in the seeds, had named as cycad Cycas fern or fern (cycadofilices). Minority class secondary xylem dense wood type. Anthers and ovules of diverse forms. Ovule integument with distinct. Structure and seed ovule 苏铁纲 similar to this program so far found only two cases of seeds with embryo preservation and the vast majority of the female gametophyte archegonial and therefore, the so-called seed is actually mostly unfertilized ovules. Classification of seed ferns have different views can be used as an outline of gymnosperms doors are also independent of a door. Gang seed ferns including nine projects: ① fern wrinkle eye, appeared in the Carboniferous; ② wood pulp project, appeared in the Carboniferous-Permian; ③ America seed head, appeared in the Late Carboniferous; ④ aloe fern seed mesh mesh or America , appeared in the Late Devonian to Early Carboniferous; ⑤ open eyes, appeared in the Triassic to Cretaceous; ⑥ pocket-shaped seed head, Triassic; ⑦ shield seed head, Triassic; ⑧ mesh tongue fern , appeared in the Permian to Triassic; ⑨ Gigantopteris head, appeared in the Early Permian to early Triassic. Except for a few ancient seed fern found that "seed" (ovules), most of the fern leaf type according pinnules (leaflets) shape, venation and rachis branches form of the name is documented in various forms, such as Wedge fern, fern veins, seat extension fern, fern teeth, abnormal fern, Gigantopteris so on. While some forms are as wedge in the seed ferns and fern ferns can have this leaf type, but included in this form of the species name is an objective reality, they have distribution in a certain period in history law can be used to divide, stratigraphic determine its age. Amon in gymnosperms an ancient and primitive classes. Stems secondary xylem. The shape of the leaves and ferns are similar, but on the raw seeds. Flourished in the Carboniferous and Permian, a few are to survive in the Triassic and Jurassic.
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Seed fern is one of the most primitive seed plants, ferns is between one group and cycads between. Modern Sutie Gang plant is clearly the most primitive group of modern gymnosperms. Seed ferns are terrestrial plant taxa among the earliest successful one, and the seed fern forests dominated late in the Paleozoic popularity throughout the world. Tongue fern genus is the case during the Permian Gondwana continent in the most common trees. To the Triassic, the importance of seed ferns ecologically began to decline, today gymnosperms then began to spread, until the end of the Cretaceous, flowering plants began to spread of. Seed ferns in the Carboniferous and Permian periods, in the northern hemisphere had a very prosperous after the proposed cycads evolved (Cycadeoideinae) (the inner cycads Benettitinae) and was Di harsh plant (Cordaitinae). Intends cycads may be directly derived from wood pulp (Medullosa) seed fern class 苏铁纲 existing plants as well as plants and wood pulp proposed cycads have a lot in common, it may be their descendants. Ginkgo plants and conifers plants, no doubt also have harsh Di descendants of plants. Gnetum plants in the modern gymnosperms are special and isolated group, according to the characteristics of cones, are considered descendants of degradation is likely to be strong and specialization of the proposed cycad plants. Plant seed ferns are generally small, most of the students are leaning or climbing this type. Also part of the upright tree fern-like, unbranched, up to 10 meters, or erect stout small tree. The vast majority of seed fern plants like ferns with large fern leaf (mostly pinnate) and pulse sequence, the difference is in the type of reproductive fern leaf length seeds and pollen sacs, often the main two fern leaf petiole bifurcations, cuticle thick leaf surface. Anatomy of stems and roots of ferns Gang is both traits and traits with gymnosperms, a native of columns, column or really where the body of the column. There marrow stem pith often large, thick cortex and secondary vascular tissue thin, sparse wood type secondary xylem anatomy and 苏铁纲 their most similar, never found before in the seeds, had named as cycad Cycas fern or fern (Cycadofilices). Minority class secondary xylem dense wood type. Anthers and ovules of diverse forms. Ovule integument with distinct. Structure and seed ovule 苏铁纲 similar to this program so far found only two cases of seeds with embryo preservation and the vast majority of the female gametophyte archegonial and therefore, the so-called seed is actually mostly unfertilized ovules. Classification of seed ferns have different views can be used as an outline of gymnosperms doors are also independent of a door. Gang seed ferns including nine projects: ① fern wrinkle eye, appeared in the Carboniferous; ② wood pulp project, appeared in the Carboniferous-Permian; ③ America seed head, appeared in the Late Carboniferous; ④ aloe fern seed mesh mesh or America , appeared in the Late Devonian to Early Carboniferous; ⑤ open eyes, appeared in the Triassic to Cretaceous; ⑥ pocket-shaped seed head, Triassic; ⑦ shield seed head, Triassic; ⑧ mesh tongue fern , appeared in the Permian to Triassic; ⑨ Gigantopteris head, appeared in the Early Permian to early Triassic. Except for a few ancient seed fern found that "seed" (ovules), most of the fern leaf type according pinnules (leaflets) shape, venation and rachis branches form of the name is documented in various forms, such as Wedge fern, fern veins, seat extension fern, fern teeth, abnormal fern, Gigantopteris so on. While some forms are as wedge in the seed ferns and fern ferns can have this leaf type, but included in this form of the species name is an objective reality, they have distribution in a certain period in history law can be used to divide, stratigraphic determine its age. Amon in gymnosperms an ancient and primitive classes. Stems secondary xylem. The shape of the leaves and ferns are similar, but on the raw seeds. Flourished in the Carboniferous and Permian, a few are to survive in the Triassic and Jurassic.