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The gymnosperms (/ ˈ dʒ ɪ m n ə ˌ s p ɜːr m z,-n oʊ-/ ⓘ nə-spurmz, -noh-; lit. ' revealed seeds ') are a group of woody, perennial seed-producing plants, typically lacking the protective outer covering which surrounds the seeds in flowering plants, that include conifers, cycads, Ginkgo, and gnetophytes, forming the clade Gymnospermae [2] The term gymnosperm comes from the ...
Cross section of ovule in gymnosperms and angiosperms. Gymnosperm pollen is produced in microsporangia borne on the scales of the male cone or microstrobilus.In most species, the plants are wind-pollinated, and the pollen grains of conifers have air bladders that provide buoyancy in air currents.
Plant reproductive morphology is the study of the physical form and structure (the morphology) of those parts of plants directly or indirectly concerned with sexual reproduction. Among all living organisms, flowers , which are the reproductive structures of angiosperms , are the most varied physically and show a correspondingly great diversity ...
Plant anatomy or phytotomy is the general term for the study of the internal structure of plants. Originally, it included plant morphology , the description of the physical form and external structure of plants, but since the mid-20th century, plant anatomy has been considered a separate field referring only to internal plant structure.
Gymnosperms are divided into 12 families of trees, shrubs and woody vines. [5] Sequoiadendron giganteum, the giant redwood, is the largest tree in the world, and Sequoia sempervirens, the coastal redwood, is the tallest. [6] Ginkgo trees tolerate urban pollutants well, and are often planted in and near cities. [7]
The stem anatomy of ferns is more complicated than that of dicots because fern stems often have one or more leaf gaps in cross section. A leaf gap is where the vascular tissue branches off to a frond. In cross section, the vascular tissue does not form a complete cylinder where a leaf gap occurs.
Gnetophyta (/ n ɛ ˈ t ɒ f ɪ t ə, ˈ n ɛ t oʊ f aɪ t ə /) is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales), grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three relict genera: Gnetum (family Gnetaceae), Welwitschia (family Welwitschiaceae), and Ephedra (family ...
Ginkgoales are a gymnosperm order containing only one extant species: Ginkgo biloba, the ginkgo tree. [1] The order has a long fossil record extending back to the Early Permian around 300 million years ago from fossils found worldwide. The order was a common component of Permian and Triassic flora before the super dominance of conifers.