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The term "gymnosperm" is often used in paleobotany to refer to (the paraphyletic group of) all non-angiosperm seed plants. In that case, to specify the modern monophyletic group of gymnosperms, the term Acrogymnospermae is sometimes used. The gymnosperms and angiosperms together constitute the spermatophytes or seed plants.
Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta ( / pɪˈnɒfɪtə, ˈpaɪnoʊfaɪtə / ), also known as Coniferophyta ( / ˌkɒnɪfəˈrɒfɪtə, - oʊfaɪtə /) or Coniferae. The division contains a single extant class, Pinopsida.
Microphylls and megaphylls. In plant anatomy and evolution a microphyll (or lycophyll) is a type of plant leaf with one single, unbranched leaf vein. [1] Plants with microphyll leaves occur early in the fossil record, and few such plants exist today. In the classical concept of a microphyll, the leaf vein emerges from the protostele without ...
Euphyllophyte. The euphyllophytes are a clade of plants within the tracheophytes (the vascular plants). The group may be treated as an unranked clade, [1] a division under the name Euphyllophyta [2] or a subdivision under the name Euphyllophytina. [3] The euphyllophytes are characterized by the possession of true leaves ("megaphylls"), and ...
A cotyledon ( / ˌkɒtɪˈliːdən /; from Latin cotyledon; [1] from κοτυληδών (kotulēdṓn) "a cavity, small cup, any cup-shaped hollow", [2] gen. κοτυληδόνος ( kotulēdónos ), from κοτύλη ( kotýlē) 'cup, bowl') is a "seed leaf" - a significant part of the embryo within the seed of a plant, and is formally defined ...
Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae within the Gnetophyta. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms, they possess vessel elements in the xylem. Some species have been proposed to have been the first plants to be insect- pollinated as their fossils occur in association ...
Welwitschia is a monotypic genus (that is, a genus that contains a single recognised species) of gymnosperm, the sole described species being the distinctive Welwitschia mirabilis, endemic to the Namib desert within Namibia and Angola. Welwitschia is the only living genus of the family Welwitschiaceae and order Welwitschiales in the division ...
Gymnosperms are divided into 12 families of trees, shrubs and woody vines. Sequoiadendron giganteum, the giant redwood, is the largest tree in the world, and Sequoia sempervirens, the coastal redwood, is the tallest. Ginkgo trees tolerate urban pollutants well, and are often planted in and near cities.