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The gymnosperms (/ ˈ dʒ ɪ m n ə ˌ s p ɜːr m z,-n oʊ-/ ⓘ JIM-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 ...
The gymnosperms consist of five orders of seed plants: Cupressales, Cycadales, Ginkgoales, Gnetales and Pinales. [a] They developed more than 350 million years ago, long before flowering plants, according to the fossil record. The name comes from the Greek for "naked seed"; the egg cells are not protected by ovaries, as in flowering plants. [4]
This neurotoxin may enter a human food chain as the cycad seeds may be eaten directly as a source of flour by humans or by wild or feral animals such as bats, and humans may eat these animals. It is hypothesized that this is a source of some neurological diseases in humans.
Wind and animal dispersals are two major mechanisms involved in the dispersal of conifer seeds. Wind-born seed dispersal involves two processes, namely; local neighborhood dispersal and long-distance dispersal. Long-distance dispersal distances range from 11.9–33.7 kilometres (7.4–20.9 mi) from the source. [26]
The family Ephedraceae, of which Ephedra is the only extant genus, are gymnosperms, and generally shrubs, sometimes clambering vines, and rarely, small trees. Members of the genus frequently spread by the use of rhizomes. [3] The stems are green and photosynthetic. [4]
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 ...
Pages in category "Gymnosperms" The following 4 pages are in this category, out of 4 total. This list may not reflect recent changes. 0–9. Gymnosperm; A ...
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.