Search results
Results from the WOW.Com Content Network
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 ...
Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (/ p ɪ ˈ n ɒ f ɪ t ə, ˈ p aɪ n oʊ f aɪ t ə /), also known as Coniferophyta (/ ˌ k ɒ n ɪ f ə ˈ r ɒ f ɪ t ə,-oʊ f aɪ t ə /) or Coniferae. The division contains a single extant class, Pinopsida.
The name comes from the Greek for "naked seed"; the egg cells are not protected by ovaries, as in flowering plants. [4] 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]
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 ...
A conifer cone, or in formal botanical usage a strobilus, pl.: strobili, is a seed-bearing organ on gymnosperm plants, especially in conifers and cycads. They are usually woody and variously conic, cylindrical, ovoid, to globular, and have scales and bracts arranged around a central axis, but can be fleshy and berry -like.
Among the seed plants, the gymnosperms are a sister group to the subclass Magnoliidae (angiosperms or flowering plants). There are about 1000 extant gymnosperm species, distributed over about 12 families and 83 genera. Many of these genera are monotypic (41%), and another 27% are oligotypic (2–5 species). [27]
Cordaites is a genus of extinct gymnosperms, related to or actually representing the earliest conifers. These trees grew up to 100 feet (30 m) tall and stood in dry areas as well as wetlands. Brackish water mussels and crustacea are found frequently between the roots of these trees.
The female seed cones are solitary. Their peduncles may have small scale leaves. The cones consist of several sterile cone scales and one fertile cone scale with just one seed producing ovule. The sterile scales wither as the cone matures, unlike in the closely related genus Podocarpus where the scales fuse to form a fleshy receptacle. A part ...