Search results
Results from the WOW.Com Content Network
A sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls (whether they are microphylls or megaphylls) bear either megasporangia and thus are called megasporophylls , or microsporangia and are called microsporophylls .
In flowering plants, the gametophytes are very reduced in size, and are represented by the germinated pollen and the embryo sac The sporophyte produces spores (hence the name) by meiosis , a process also known as "reduction division" that reduces the number of chromosomes in each spore mother cell by half.
A strobilus (pl.: strobili) is a structure present on many land plant species consisting of sporangia-bearing structures densely aggregated along a stem.Strobili are often called cones, but some botanists restrict the use of the term cone to the woody seed strobili of conifers.
Flowering plants contain microsporangia in the anthers of stamens (typically four microsporangia per anther) and megasporangia inside ovules inside ovaries. In all seed plants, spores are produced by meiosis and develop into gametophytes while still inside the sporangium. The microspores become microgametophytes (pollen).
The male cones are solitary, ovoid, 30 cm long and 7.5 cm broad, with an apical spine and rhomboid sporophyll face. The species is unusual in that it contains a layer of fleshy material between the sarcotesta and the sclerotesta that is thought to aid the seed by providing it with a source of water. As cycad seeds have no dormancy, this would ...
Right: the dry brown stalk, yellow: two seeds, left: the strongly hairy, flat part of the sporophyll. The method of pollination for Dioon plants, whether by wind or animals, has not yet been conclusively determined. The characteristics of the pollen, such as being light, dry, and present in large quantities, suggest wind pollination, which ...
Plants that are homosporous produce spores of the same size and type. Heterosporous plants, such as seed plants , spikemosses , quillworts , and ferns of the order Salviniales produce spores of two different sizes: the larger spore (megaspore) in effect functioning as a "female" spore and the smaller (microspore) functioning as a "male".
In Selaginella, each microphyll and sporophyll has a small scale-like outgrowth called a ligule at the base of the upper surface. [5]: 7 The plants are heterosporous with spores of two different size classes, known as megaspores and microspores. [6]