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Cryptostoma
Cryptostomata (singular: cryptostoma) are structures found in some types of brown algae. The anatomical structures are found in some species of ''Fucus'', but not in ''Pelvetia canaliculata''. They are conceptacle Conceptacles are specialized cavities of marine and freshwater algae that contain the reproductive organs. They are situated in the receptacle and open by a small ostiole.Boney, A.D. (1969). ''A Biology of Marine Algae''. Hutchinson Educational L ...s, sterile cavities, producing only hairs. They are found on the lamina of ''Fucus serratus''. Colourless tufts of hairs can be seen issuing from them. They are also sometimes referred to by the German name of Fasergrübchen. References {{reflist Algal anatomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelvetia Canaliculata
''Pelvetia canaliculata'', the channelled wrack, is a very common brown alga (Phaeophyceae) found on the rocks of the upper shores of Europe. It is the only species remaining in the monotypic genus ''Pelvetia''. In 1999, the other members of this genus were reclassified as ''Silvetia'' due to differences of oogonium structure and of nucleic acid sequences of the rDNA. Description ''Pelvetia'' grows to a maximum length of in dense tufts, the fronds being deeply channeled on one side: the channels and a mucus layer help prevent the seaweed drying (desiccation) when the tide is out. It is irregularly dichotomously branched with terminal receptacles, and is dark brown in color. Each branch is of uniform width and without a midrib. The receptacles are forked at the tips. It is distinguished from other large brown algae by the channels along the frond. It has no mid-rib, no air-vesicles and no cryptostomata. It forms the uppermost zone of algae on the shore growing at or above high- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fucus
''Fucus'' is a genus of brown algae found in the intertidal zones of rocky seashores almost throughout the world. Description and life cycle The thallus is perennial with an irregular or disc-shaped holdfast or with haptera. The erect portion of the thallus is dichotomous or subpinnately branched, flattened and with a distinct midrib. Gas-filled pneumatocysts (air-vesicles) are present in pairs in some species, one on either side of the midrib. The erect portion of the thallus bears cryptostomata and caecostomata (sterile surface cavities). The base of the thallus is stipe-like due to abrasion of the tissue lateral to the midrib and it is attached to the rock by a holdfast. The gametangia develop in conceptacles embedded in receptacles in the apices of the final branches. They may be monoecious or dioecious. These algae have a relatively simple life cycle and produce only one type of thallus which grows to a maximum size of 2 m. Fertile cavities, the conceptacles, conta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conceptacle
Conceptacles are specialized cavities of marine and freshwater algae that contain the reproductive organs. They are situated in the receptacle and open by a small ostiole.Boney, A.D. (1969). ''A Biology of Marine Algae''. Hutchinson Educational Ltd, London Conceptacles are present in Corallinaceae,Irvine, L.M. and Chamberlain, Y.M. (1994). ''Seaweeds of the British Isles''. Volume 1, Part 2B. Natural History Museum, London. and Hildenbrandiales, as well as the brown Fucales. In the Fucales there is no haploid phase in the reproductive cycle and therefore no alternation of generations.Fritsch, F.E. (1945). ''The Structure and Reproduction of the Algae''. Vol 2. Cambridge University Press, Cambridge The thallus is a sporophyte.Smith, G.M. (1938). ''Cryptogamic Botany. Algae and Fungi''. Second edition, Volume ''1'', McGraw-Hill Bok Company, Inc. The diploid plants produce male (antheridia) and female (oogonia) gametangia by meiosis. The gametes are released into the surrounding wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Algae
Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. They are dominant on rocky shores throughout cooler areas of the world. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. For instance, ''Macrocystis'', a kelp of the order Laminariales, may reach in length and forms prominent underwater kelp forests. Kelp forests like these contain a high level of biodiversity. Another example is ''Sargassum'', which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Some members of the class, such as kelps, are used by humans as food. Between 1,500 and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
