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Just as with bryophytes and spermatophytes (seed plants), the life cycle of pteridophytes involves alternation of generations. This means that a diploid generation (the sporophyte, which produces spores) is followed by a haploid generation (the gametophyte or prothallus, which produces gametes). Pteridophytes differ from bryophytes in that the ...
Bryophytes (/ ˈ b r aɪ. ə ˌ f aɪ t s /) [2] are a group of land plants (embryophytes), sometimes treated as a taxonomic division, that contains three groups of non-vascular land plants: the liverworts, hornworts, and mosses (Bryophyta sensu lato). [3]
1. A space between the threads of a net, e.g. that part of a leaf surface defined by each of the elements of a vein network; as with cacti, the area between the veinlets of a leaf. 2. A structure on the stem node of a cactus, morphologically a specialised branch; the region of a cactus upon which spine s, glochid s, and flowers are borne. aril
During the Silurian and Devonian periods (around ), plants evolved which possessed true vascular tissue, including cells with walls strengthened by lignin . Some extinct early plants appear to be between the grade of organization of bryophytes and that of true vascular plants (eutracheophytes).
The gametophyte is the most commonly known phase of the plant. Bryophytes are typically small plants that grow in moist locations and like ferns, have motile sperm which swim to the ovule using flagella and therefore need water to facilitate sexual reproduction. Bryophytes show considerable variation in their reproductive structures, and a ...
By contrast, mosses and other bryophytes have only a single set of chromosomes and so are haploid (i.e. each chromosome exists in a unique copy within the cell). There is a period in the moss life cycle when they do have a double set of paired chromosomes, but this happens only during the sporophyte stage.
In the same period total trade between the two countries was worth 294 billion pounds, making the United States Britain's biggest trading partner as a single country, although the European Union ...
Older morphological studies believed in a close relationship between the gnetophytes and the angiosperms, [6] in particular based on vessel elements. However, molecular studies (and some more recent morphological [ 7 ] [ 8 ] and fossil [ 9 ] papers) have generally shown a clade of gymnosperms , with the gnetophytes in or near the conifers.