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Desmarestiales
Desmarestiales is an order in the brown algae (Phaeophyceae). Members of this order have terete or ligulate (flat) pinnately branched thalli attached by discoid holdfasts. They have a sporophytic thallus usually aggregated to form a pseudo-parenchyma.Pound F.E. 1962 “The Biology of the Algae” Edward Arnold Ltd. The order gets its name from the genus '' Desmarestia'', which is named after the French zoologist Anselme Gaëtan Desmarest (1784–1838).Genaust, Helmut (1976). ''Etymologisches Wörterbuch der botanischen Pflanzennamen'' As the general name of the class suggests, their pigment A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...ation is brown. References Further reading External links AlgaeBase Brown algae orders {{Phaeophyceae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Algae
Brown algae (: alga) are a large group of multicellular algae comprising the class (biology), class Phaeophyceae. They include many seaweeds located in colder waters of the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. 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 that 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. Some members of the class, such as kelps, are used by humans as food. Between 1,500 and 2,000 species of brown algae are known worldwide. Some species, such as ''Ascophyllum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmarestiaceae
Desmarestiaceae is a family of brown algae, one of two families in the order Desmarestiales.Guiry, M. D. & G. M. Guiry. 2013Desmarestiales.AlgaeBase. National University of Ireland, Galway. Accessed 04 June 2013. The family gets its name from the genus '' Desmarestia'', which is named after the French zoologist Anselme Gaëtan Desmarest (1784-1838). There are three genera in this family. Two are monotypic, '' Himantothallus'' (species name '' Himantothallus grandifolius'') and '' Phaeurus'' (species name '' Phaeurus antarcticus''). These are both endemic to Antarctica. The third genus, '' Desmarestia'', has 30Guiry, M. D. & G. M. Guiry. 2013''Desmarestia''.AlgaeBase. National University of Ireland, Galway. Accessed 04 June 2013. to 40 species. Most species have narrow, localized ranges, but some ''Desmarestia'', such as '' D. ligulata'' and '' D. viridis'', have disjunct but global distributions. It is thought that the family began its evolution in the Southern Hemisphere and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anselme Gaëtan Desmarest
Anselme Gaëtan Desmarest (6 March 1784 – 4 June 1838) was a French Zoology, zoologist and author. He was the son of Nicolas Desmarest and the father of Eugène Anselme Sébastien Léon Desmarest. Career Desmarest was a disciple of Georges Cuvier and Alexandre Brongniart, and in 1815, he succeeded Pierre André Latreille to the professorship of zoology at the '. He was elected to the American Philosophical Society in 1819 and to the Académie Nationale de Médecine in 1820. Publications Desmarest published ' (1805), ' (1825), ' (1820), and ' (1816–30, with André Marie Constant Duméril). His ''Mammalogie'' was significant as it contained a comprehensive list of all mammals known at the time, including living forms and extinct forms known only from fossils. Desmarest was one of the first scientists to routinely apply both genus and species names to animals. Prior to his time, it was common practice to give only a genus name to a new animal. Legacy The common name, Desmarest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmarestia Aculeata
''Desmarestia aculeata'' is a species of brown algae found worldwide. Its common names include color changer, Desmarest's flattened weed, and sea sorrel, though the last name can refer to other species of ''Desmarestia ''Desmarestia'' is a genus of brown algae found worldwide. It is also called acid weed, acid kelp, acidweed, ', sea sorrel, (), ', mermaid's hair, landlady's wig, or '. However, 'sea sorrel' can also specifically refer to ''Desmarestia virid ...''. Photos File:Desmarestia_aculeata_19880601a.jpg, Collected and pressed sample 1988 Desmarestia_aculeata_Helgoland.JPG, Collected and pressed sample 1985 FMIB_53673_Algues_brunes%2C_Pheophycees.jpeg, Aquatic Botany 1906 Artist rendition Desmarestia aculeata - figure 13a/b Icones_of_Japanese_algae_(9935942666).jpg, Icones of Japanese algae v.4 1907-1942 Desmarestia aculeata figures 5 - 9 British_sea-weeds_-_drawn_from_Professor_Harvey's_"Phycologia_Britannica"_(1872)_(20410048932).jpg, British seaweeds Artist rendi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk (mathematics)
In geometry, a disk (Spelling of disc, also spelled disc) is the region in a plane (geometry), plane bounded by a circle. A disk is said to be ''closed'' if it contains the circle that constitutes its boundary, and ''open'' if it does not. For a radius r, an open disk is usually denoted as D_r, and a closed disk is \overline. However in the field of topology the closed disk is usually denoted as D^2, while the open disk is \operatorname D^2. Formulas In Cartesian coordinates, the ''open disk'' with center (a, b) and radius ''R'' is given by the formula D = \, while the ''closed disk'' with the same center and radius is given by \overline = \. The area (geometry), area of a closed or open disk of radius ''R'' is π''R''2 (see area of a disk). Properties The disk has circular symmetry. The open disk and the closed disk are not topologically equivalent (that is, they are not homeomorphism, homeomorphic), as they have different topological properties from each other. For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmarestia
''Desmarestia'' is a genus of brown algae found worldwide. It is also called acid weed, acid kelp, acidweed, ', sea sorrel, (), ', mermaid's hair, landlady's wig, or '. However, 'sea sorrel' can also specifically refer to ''Desmarestia viridis''. Members of this genus can be either annual or perennial. Annual members of this genus store sulfuric acid in intracellular vacuoles. When exposed to air they release the acid, thereby destroying themselves and nearby seaweeds in the process. They are found in shallow intertidal zones. Ingesting sulfuric acid can cause severe digestive disturbances. but since sulfuric acid tastes extremely sour, members of the genus are unlikely to be eaten in harmful quantities. The genus was named in honor of Anselme Gaëtan Desmarest. Species AlgaeBase lists 32 currently accepted species within the genus ''Desmarestia'', not including variations and subspecies. * '' Desmarestia aculeata'' ( L.) J.V.Lamouroux - Type specimen for the genus * '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. Phylogeneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudo-parenchyma
This glossary of mycology is a list of definitions of terms and concepts relevant to mycology, the study of fungi. Terms in common with other fields, if repeated here, generally focus on their mycology-specific meaning. Related terms can be found in glossary of biology and glossary of botany, among others. List of Latin and Greek words commonly used in systematic names and Botanical Latin may also be relevant, although some prefixes and suffixes very common in mycology are repeated here for clarity. A B C D E F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sporophyte
A sporophyte () is one of the two alternation of generations, alternating multicellular organism, multicellular phases in the biological life cycle, life cycles of plants and algae. It is a diploid multicellular organism which produces asexual Spore, spores. This stage Alternation of generations, alternates with a multicellular haploid gametophyte phase. Life cycle The sporophyte develops from the zygote produced when a haploid egg cell is fertilized by a haploid sperm and each sporophyte cell therefore has a double set of chromosomes, one set from each parent. All Embryophyta, land plants, and most multicellular algae, have life cycles in which a multicellular diploid sporophyte phase alternates with a multicellular haploid gametophyte phase. In the Spermatophyte, seed plants, the largest groups of which are the gymnosperms (bare seeds) and angiosperms (fruiting plants), the sporophyte phase is more prominent than the gametophyte, and is the familiar green plant with its roots, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...s. 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 liv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinnation
Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and in patterns of erosion or stream beds. The term derives from the Latin word ''pinna'' meaning "feather", "wing", or " fin". A similar concept is "pectination", which is a comb-like arrangement of parts (arising from one side of an axis only). Pinnation is commonly referred to in contrast to "palmation", in which the parts or structures radiate out from a common point. The terms "pinnation" and "pennation" are cognate, and although they are sometimes used distinctly, there is no consistent difference in the meaning or usage of the two words.Jackson, Benjamin, Daydon; ''A Glossary of Botanic Terms with their Derivation and Accent''. Gerald Duckworth & Co. London, 4th ed 1928. Plants Botanically, pinnation is an arrangement of discrete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thallus
Thallus (: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. A thallus usually names the entire body of a multicellular non-moving organism in which there is no organization of the tissues into organs. Many of these organisms were previously known as the thallophytes, a polyphyletic group of distantly related organisms. An organism or structure resembling a thallus is called thalloid, thalloidal, thalliform, thalline, or thallose. Even though thalli do not have organized and distinct parts ( leaves, roots, and stems) as do the vascular plants, they may have analogous structures that resemble their vascular "equivalents". The analogous structures have similar function or macroscopic structure, but different microscopic structure; for example, no thallus has vascular tissue. In exceptional cases such as the Lemnoideae, where th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
