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Polysiphonia Fucoides
''Polysiphoides fucoides'' (Hudson) Greville (''Vertebrata fucoides'')Bunker, F.StP.D., Brodie, Juliet, A., Maggs, C.A. and Bunker, A.R. 2017. ''Seaweeds of Britain and Ireland.'' Second Edition. Wild Nature Press, Plymouth, UK. is a common marine algaHardy, F.G. and Guiry, M.D. 2003 ''A Check-list and Atlas of the Seaweeds of Britain and Ireland.'' The British Phycological Society. in the Division Rhodophyta. Description ''Polysiphonia fucoides'' is a relatively small seaweed. It grows as branched, cylindrical tufts reaching 30 cm or more in length. The branches are themselves densely branched, the main branch usually distinct. It is attached by matted branches which produce rhizoids. The branches are composed of a central axes of cells surrounded by 11 to 21 pericentral cells all of the same length. Cortication is generally absent but may be formed on the major branches near the holdfast, with the cells growing down in grooves between the pericentral cells.Maggs, C.A. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alga
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as ''Chlorella,'' ''Prototheca'' and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to in length. Most are aquatic and autotrophic (they generate food internally) and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the ''Charophyta'', a division of green algae which includes, for example, ''Spirogyra'' and stoneworts. No definition of algae is generally accepted. One definition is that algae "have chlorophyll ''a'' as their primary photosynthetic pigment and lack a sterile covering of cells around t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhodophyta
Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority of species (6,793) are found in the Florideophyceae (class), and mostly consist of multicellular, marine algae, including many notable seaweeds. Red algae are abundant in marine habitats but relatively rare in freshwaters. Approximately 5% of red algae species occur in freshwater environments, with greater concentrations found in warmer areas. Except for two coastal cave dwelling species in the asexual class Cyanidiophyceae, there are no terrestrial species, which may be due to an evolutionary bottleneck in which the last common ancestor lost about 25% of its core genes and much of its evolutionary plasticity. The red algae form a distinct group characterized by having eukaryotic cells without flagella and centrioles, chloroplasts tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhizoids
Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be unicellular or multicellular. Evolutionary development Plants originated in aquatic environments and gradually migrated to land during their long course of evolution. In water or near it, plants could absorb water from their surroundings, with no need for any special absorbing organ or tissue. Additionally, in the primitive states of plant development, tissue differentiation and division of labor was minimal, thus specialized water absorbing tissue was not required. The development of specialized tissues to absorb water efficiently and anchor themselves to the ground enabled the spread of plants to the land. Description Rhizoids absorb water mainly by capillary action, in which water moves up between threads of rhizoids and not through ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cortication
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.Introduction to Lichens – An Alliance between Kingdoms . University of California Museum of Paleontology. Lichens have properties different from those of their component organisms. They come in many colors, sizes, and forms and are sometimes plant-like, but are not s. They may have tiny, leafless branches (); flat leaf-like structures ( |
Holdfast (biology)
A holdfast is a root-like structure that anchors aquatic sessile organisms, such as seaweed, other sessile algae, stalked crinoids, benthic cnidarians, and sponges, to the substrate. Holdfasts vary in shape and form depending on both the species and the substrate type. The holdfasts of organisms that live in muddy substrates often have complex tangles of root-like growths. These projections are called haptera and similar structures of the same name are found on lichens. The holdfasts of organisms that live in sandy substrates are bulb-like and very flexible, such as those of sea pens, thus permitting the organism to pull the entire body into the substrate when the holdfast is contracted. The holdfasts of organisms that live on smooth surfaces (such as the surface of a boulder) have flattened bases which adhere to the surface. The organism derives no nutrition from this intimate contact with the substrate, as the process of liberating nutrients from the substrate requires ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corticate
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Dioecious
Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is biparental reproduction. Dioecy has costs, since only about half the population directly produces offspring. It is one method for excluding self-fertilization and promoting allogamy (outcrossing), and thus tends to reduce the expression of recessive deleterious mutations present in a population. Plants have several other methods of preventing self-fertilization including, for example, dichogamy, herkogamy, and self-incompatibility. Dioecy is a dimorphic sexual system, alongside gynodioecy and androdioecy. In zoology In zoology, dioecious species may be opposed to hermaphroditic species, meaning that an individual is either male or female, in which case the synonym gonochory is more often used. Most animal species are dioecious (gon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cystocarp
A cystocarp is the fruiting structure produced in the red algae after fertilization, especially such a structure having a special protective envelope (as in ''Polysiphonia)''. The structure from which carpospore A carpospore is a diploid spore produced by red algae. After fertilization, the alga's carpogonium subdivides into carpospores, and generally the largest type of spore (larger than bispores, which are larger again than tetraspores Tetraspores are ...s are released.Maggs, C.A. and Hommersand, M.H. 1993. ''Seaweeds of the British Isles Volume 1 Rhodophyta Part 3A Ceramiales.'' The Natural History Museum, London References {{reflist Algal anatomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is dominated by a maritime climate with narrow temperature differences between seasons. The 60% smaller island of Ireland is to the west—these islands, along with over 1,000 smaller surrounding islands and named substantial rocks, form the British Isles archipelago. Connected to mainland Europe until 9,000 years ago by a landbridge now known as Doggerland, Great Britain has been inhabited by modern humans for around 30,000 years. In 2011, it had a population of about , making it the world's third-most-populous island after Java in Indonesia and Honshu in Japan. The term "Great Britain" is often used to refer to England, Scotland and Wales, including their component adjoining islands. Great Britain and Northern Ireland now constitute the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ireland
Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Great Britain and Ireland), North Channel, the Irish Sea, and St George's Channel. Ireland is the List of islands of the British Isles, second-largest island of the British Isles, the List of European islands by area, third-largest in Europe, and the List of islands by area, twentieth-largest on Earth. Geopolitically, Ireland is divided between the Republic of Ireland (officially Names of the Irish state, named Ireland), which covers five-sixths of the island, and Northern Ireland, which is part of the United Kingdom. As of 2022, the Irish population analysis, population of the entire island is just over 7 million, with 5.1 million living in the Republic of Ireland and 1.9 million in Northern Ireland, ranking it the List of European islan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isle Of Man
) , anthem = "O Land of Our Birth" , image = Isle of Man by Sentinel-2.jpg , image_map = Europe-Isle_of_Man.svg , mapsize = , map_alt = Location of the Isle of Man in Europe , map_caption = Location of the Isle of Man (green) in Europe (dark grey) , subdivision_type = Sovereign state , subdivision_name = United Kingdom , established_title = Norse control , established_date = 9th century , established_title2 = Scottish control , established_date2 = 2 July 1266 , established_title3 = English control , established_date3 = 1399 , established_title4 = Revested into British Crown , established_date4 = 10 May 1765 , official_languages = , capital = Douglas , coordinates = , demonym = Manx; Manxman (plural, Manxmen); Manxwoman (plural, Manxwomen) , ethnic_groups = , ethnic_groups_year = 2021 , ethnic_groups_ref = Official census statistics provided by Statistics Isle of Man, Isle of Man Government: * * , religion = , religion_year = 2021 , relig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channel Islands
The Channel Islands ( nrf, Îles d'la Manche; french: îles Anglo-Normandes or ''îles de la Manche'') are an archipelago in the English Channel, off the French coast of Normandy. They include two Crown Dependencies: the Bailiwick of Jersey, which is the largest of the islands; and the Bailiwick of Guernsey, consisting of Guernsey, Alderney, Sark, Herm and some smaller islands. They are considered the remnants of the Duchy of Normandy and, although they are not part of the United Kingdom, the UK is responsible for the defence and international relations of the islands. The Crown dependencies are not members of the Commonwealth of Nations, nor have they ever been in the European Union. They have a total population of about , and the bailiwicks' capitals, Saint Helier and Saint Peter Port, have populations of 33,500 and 18,207, respectively. "Channel Islands" is a geographical term, not a political unit. The two bailiwicks have been administered separately since the late ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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