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Conceptacles
Conceptacles are specialized cavities of marine and freshwater algae that contain the reproductive organs. They are situated in the Receptacle (botany), receptacle and open by a small ostiole.Boney, A.D. (1969). ''A Biology of Marine Algae''. Hutchinson Educational Ltd, London Conceptacles are present in Coralline algae, Corallinaceae,Irvine, L.M. and Chamberlain, Y.M. (1994). ''Seaweeds of the British Isles''. Volume 1, Part 2B. Natural History Museum, London, Natural History Museum, London. and Hildenbrandiales, as well as the brown alga, brown Fucales. In the Fucales there is no Ploidy#Haploid and monoploid, 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 (tissue), thallus is a sporophyte.Smith, G.M. (1938). ''Cryptogamic Botany. Algae and Fungi''. Second edition, Volume ''1'', McGraw-Hill Bok Company, Inc. The Ploidy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hildenbrandiales
Hildenbrandiales is an order of crustose forms red alga which bear conceptacles and produce secondary pit-connections. They reproduce by vegetative gemma (botany), gemmae as well as tetrasporangia, which are produced inside the conceptacles. The way in which the tetraspores are produced is unusual enough to justify the formation of this distinct order. Some members of the order are known from freshwater rivers as well . Systematics Hildenbradiales are difficult to discriminate on morphological grounds; tetrasporangia morphology is the only vaguely reliable character, but molecular techniques have indicated a monophyletic ''Apophlaea'' within a paraphyletic ''Hildenbrandia'', with many ''Hildenbrandia'' species being recognized as non-monophyletic. References Florideophyceae Red algae orders {{Rhodophyta-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hildenbrandiaceae
Hildenbrandiales is an order of crustose forms red alga which bear conceptacles and produce secondary pit-connections. They reproduce by vegetative gemmae as well as tetrasporangia, which are produced inside the conceptacles. The way in which the tetraspore Tetraspores are red algae spores produced by the tetrasporophytic (diploid) phase in the life history of algae in the Rhodophyta as a result of meiosis.Jones, W.E. Revised and reprinted 1964. A Key to the genera of the British seaweeds.''Field Stu ...s are produced is unusual enough to justify the formation of this distinct order. Some members of the order are known from freshwater rivers as well . Systematics Hildenbradiales are difficult to discriminate on morphological grounds; tetrasporangia morphology is the only vaguely reliable character, but molecular techniques have indicated a monophyletic '' Apophlaea'' within a paraphyletic '' Hildenbrandia'', with many ''Hildenbrandia'' species being recognized as non-monop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fucus Conceptacle
''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 conceptacle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Alga
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bossiella
''Bossiella'' is a genus of coralline algae with 5 recognised species. It reproduces via conceptacles; individual thalli only produce conceptacles of a single sex. Species The valid species currently considered to belong to this genus are: *'' Bossiella californica'' *'' Bossiella chiloensis'' *'' Bossiella compressa'' *'' Bossiella orbigniana'' *'' Bossiella plumosa'' References * External linksImagesof ''Bossiella'' at Algaebase AlgaeBase is a global species database of information on all groups of algae, both marine and freshwater, as well as sea-grass. History AlgaeBase began in March 1996, founded by Michael Guiry. Text was copied from this source, which is avail ... Corallinaceae Red algae genera {{Rhodophyta-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygote
A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism. In multicellular organisms, the zygote is the earliest developmental stage. In humans and most other anisogamous organisms, a zygote is formed when an egg cell and sperm cell come together to create a new unique organism. In single-celled organisms, the zygote can divide asexually by mitosis to produce identical offspring. German zoologists Oscar and Richard Hertwig made some of the first discoveries on animal zygote formation in the late 19th century. Humans In human fertilization, a released ovum (a haploid secondary oocyte with replicate chromosome copies) and a haploid sperm cell ( male gamete) combine to form a single diploid cell called the zygote. Once the single sperm fuses with the oocyte, the latter completes the division of the se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prototaxites
''Prototaxites'' is a genus of terrestrial fossil fungi dating from the Middle Ordovician until the Late Devonian periods, approximately . ''Prototaxites'' formed small to large trunk-like structures up to wide, reaching in length, made up of interwoven tubes around in diameter, making it by far the largest land-dwelling organism of its time. Whilst traditionally very difficult to assign to an extant group of organisms, current opinion suggests a fungal placement for the genus. Its exact relationship with extant fungus lineages is uncertain. It was almost certainly a perennial organism that grew over multiple years. Several ecologies have been proposed, including that it was saprotrophic like many modern fungi, or that it was a lichenised autotroph. Morphology left, upDawson's 1888 reconstruction of a conifer-like ''Prototaxites'' With a diameter of up to , and a height reaching , ''Prototaxites'' fossils are remnants of by far the largest organism discovered from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproductive Initials
Reproductive initials are filaments below the cuticle surface of algae and fungi which give rise to the bulbs of spore-producing cells (in fungi, conidiophores A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to ...). References Algal anatomy {{Alga-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cortex (botany)
In botany, a cortex is an outer layer of a stem or root in a vascular plant, lying below the epidermis but outside of the vascular bundles. The cortex is composed mostly of large thin-walled parenchyma cells of the ground tissue system and shows little to no structural differentiation. The outer cortical cells often acquire irregularly thickened cell walls, and are called collenchyma cells. Plants Stems and branches In the three dimensional structure of herbaceous stems, the epidermis, cortex and vascular cambium form concentric cylinders around the inner cylindrical core of pith. Some of the outer cortical cells may contain chloroplasts, giving them a green color. They can therefore produce simple carbohydrates through photosynthesis. In woody plants, the cortex is located between the periderm (bark) and the vascular tissue ( phloem, in particular). It is responsible for the transportation of materials into the central cylinder of the root through diffusion and may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medulla
Medulla or Medullary may refer to: Science * Medulla oblongata, a part of the brain stem * Renal medulla, a part of the kidney * Adrenal medulla, a part of the adrenal gland * Medulla of ovary, a stroma in the center of the ovary * Medulla of the thymus, a part of the lobes of the thymus * Medulla of lymph node * Medulla (hair), the innermost layer of the hair shaft * Medulla, a part of the optic lobe of arthropods * Medulla (lichenology), a layer of the internal structure of a lichen * Pith, or medulla, a tissue in the stems of vascular plants Other uses * ''Medúlla'', a 2004 album by Björk * Medulla, Florida, a place in the U.S. * Las Médulas, a gold mining site in León, Spain See also * *Medullary cavity, the central cavity of bone shafts * Medullary ray (other) * ''Medulla Grammatice ''Medulla Grammatice'' or ''Medulla Grammaticae'' ("the Marrow of Grammar") is a collection of fifteenth century Latin–Middle English glossaries in the British Museum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perithallus
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