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Prothallus of the tree fern Dicksonia antarctica (note new moss plants for scale) Spore-bearing plants , like all plants, go through a life-cycle of alternation of generations . The fully grown sporophyte , what is commonly referred to as the fern , produces genetically unique spores in the sori by meiosis .
Diagram showing the alternation of generations between a diploid sporophyte (bottom) and a haploid gametophyte (top) Alternation of generations (also known as metagenesis or heterogenesis) [1] is the predominant type of life cycle in plants and algae.
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 sporophyte is branched and generally much larger and more conspicuous, and from seed plants in that both generations are ...
In most ferns, for example, in the leptosporangiate fern Dryopteris, the gametophyte is a photosynthetic free living autotrophic organism called a prothallus that produces gametes and maintains the sporophyte during its early multicellular development.
The prothallus bears spherical antheridia (s.g. antheridium) which produce antherozoids (male gametophytes) and archegonia (s.g. archegonium) which release a single oosphere. The antherozoid swims up the archegonium and fertilize the oosphere, resulting in a zygote, which will grow into a separate sporophyte, while the gametophyte shortly ...
Land plants evolved from a group of freshwater green algae, perhaps as early as 850 mya, [3] but algae-like plants might have evolved as early as 1 billion years ago. [2] The closest living relatives of land plants are the charophytes, specifically Charales; if modern Charales are similar to the distant ancestors they share with land plants, this means that the land plants evolved from a ...
From ancient history to the modern day, the clitoris has been discredited, dismissed and deleted -- and women's pleasure has often been left out of the conversation entirely. Now, an underground art movement led by artist Sophia Wallace is emerging across the globe to challenge the lies, question the myths and rewrite the rules around sex and the female body.
Closeup (10X magnification) of fibrous white prothallus. Verseghya thysanophora is pale yellow to greenish in colour, sometimes with blue or grey tones in shaded areas. It has a thin, leprose and sometimes patchy appearance. A visible, white and fibrous prothallus is often present with hyphae arranged in distinct radiating strands.