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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 ...
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]
A seed plant or spermatophyte (lit. ' seed plant '; from Ancient Greek σπέρματος (spérmatos) ' seed ' and φυτόν (phytón) ' plant '), also known as a phanerogam (taxon Phanerogamae) or a phaenogam (taxon Phaenogamae), is any plant that produces seeds.
Since the evolution of the first seeded plants ~370 million years ago, [1] the largest change in seed size was found to be at the divergence of gymnosperms and angiosperms ~325 million years ago, but overall, the divergence of seed size appears to take place relatively consistently through evolutionary time. [2]
Evolution of the angiosperms according to the Angiosperm Phylogeny Group (2013). The Angiosperm Phylogeny Group (APG) is an informal international group of systematic botanists who collaborate to establish a consensus on the taxonomy of flowering plants (angiosperms) that reflects new knowledge about plant relationships discovered through phylogenetic studies.
The first semblance of Malpighiales as now known came from a phylogeny of seed plants published in 1993 and based upon DNA sequences of the gene rbcL. [26] This study recovered a group of rosids unlike any group found in any previous system of plant classification .
Pteridospermatophyta, also called "pteridosperms" or "seed ferns" are a polyphyletic [1] grouping of extinct seed-producing plants. The earliest fossil evidence for plants of this type are the lyginopterids of late Devonian age. [ 2 ]
The Caytoniales (Figs. 1-2) are an extinct order of seed plants known from fossils collected throughout the Mesozoic Era, around 2] [3] [4] They are regarded as seed ferns because they are seed-bearing plants with fern-like leaves. [4]