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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 ...
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]
Conifers are the largest and economically most important component group of gymnosperms, but nevertheless they comprise only one of the four groups. The division Pinophyta consists of just one class, Pinopsida, which includes both living and fossil taxa. Subdivision of the living conifers into two or more orders has been proposed from time to time.
The extant spermatophytes form five divisions, the first four of which are classified as gymnosperms, plants that have unenclosed, "naked seeds": [1]: 172 Cycadophyta, the cycads, a subtropical and tropical group of plants, Ginkgophyta, which includes a single living species of tree in the genus Ginkgo,
At issue is whether the Gnetophyta are the sister group of angiosperms, or whether they are sister to, or nested within, other extant gymnosperms. Numerous fossil gymnosperm clades once existed that are morphologically at least as distinctive as the four living gymnosperm groups, such as Bennettitales, Caytonia and the glossopterids. When these ...
Gymnosperms form a group of four subclasses among the spermatophytes (seed bearing plants). In turn, the seed plants together with the monilophyte fern subclasses make up the tracheophytes (vascular plants), part of the class Equisetopsida (embryophytes or land plants), as opposed to the green algae .
The term gymnosperm was, from then-on, applied to seed plants with naked ovules, and the term angiosperm to seed plants with enclosed ovules. However, for many years after Brown's discovery, the primary division of the seed plants was seen as between monocots and dicots, with gymnosperms as a small subset of the dicots. [4]
Living order of Lycophytes and ferns are taken from Christenhusz et al. 2011b [2] and Pteridophyte Phylogeny Group. [3] Living orders of Gymnosperms are added from Christenhusz et al. 2011a [4] while extinct orders are from Anderson, Anderson & Cleal 2007. [5]