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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 sporphytic 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 colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compou ...ation is brown. References Further reading External links AlgaeBase Brown algae orders {{Phaeophyceae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 sporphytic 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 colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compou ...ation is brown. References Further reading External links AlgaeBase Brown algae orders {{Phaeophyceae-stub ... [...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.Peters, A. F., et al. (1997)Phylogeny and historical ecology of the Desmarestiaceae (Phaeophyceae) support a Southern Hemisphere origin.''J Phycol'' 33 294-309. 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 '' ... [...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 a ... [...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 father of Eugène Anselme Sébastien Léon Desmarest. 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. Desmarest published ' (1805), ' (1825), ' (1820) and ' (1816–30, with André Marie Constant Duméril). The brown algae ''Desmarestia'' is named in honour of Desmarest, as well as the family (Desmarestiaceae) — and in turn, the order (Desmarestiales) — of which the genus is the type species#In botany, type species. References French zoologists French taxonomists 1784 births 1838 deaths French carcinologists French mammalogists French ornithologists 18th-century French zoologists 19th-century French ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmarestia
''Desmarestia'' is a genus of brown algae found worldwide. It is also called acid weed, 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 problems. 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 * '' Desmarestia a ... [...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, acidweed, ', sea sorrel, (), ', mermaid's hair, landlady's wig, or '. However, 'sea sorrel' can also specifically refer to '' Desmarestia viridis''. Mem ...''. 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 sea-weeds Artist rend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Order (biology)
Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. An immediately higher rank, superorder, is sometimes added directly above order, with suborder directly beneath order. An order can also be defined as a group of related families. What does and does not belong to each order is determined by a taxonomist, as is whether a particular order should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognized only rarely. The name of an order is usually written with a capital letter. For some groups of organisms, their orders may fol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terete
Terete is a term in botany used to describe a cross section that is circular, or like a distorted circle, with a single surface wrapping around it.Lichen Vocabulary, Lichens of North America Information, Sylvia and Stephen Sharnoff/ref> This is usually contrasted with cross-sections that are flattened, with a distinct upper surface that is different from the lower surface. The cross-section of a branch in a tree is somewhat round, so the branch is terete. The cross section of a normal leaf has an upper surface, and a lower surface, so the leaf is not terete. However, the fleshy leaves of succulents are sometimes terete. Fruticose lichens are terete, with a roughly circular cross section and a single wrap-around skin-like surface called the cortex, compared to foliose lichen Foliose lichen is one of the morphological classes of lichens, which are complex organisms that arise from the symbiotic relationship between fungi and a photosynthetic partner, typically algae. This p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligule
A ligule (from "strap", variant of ''lingula'', from ''lingua'' "tongue") is a thin outgrowth at the junction of leaf and leafstalk of many grasses (Poaceae) and sedges. A ligule is also a strap-shaped extension of the corolla, such as that of a ray floret in plants in the daisy family Asteraceae. Poaceae and Cyperaceae The ligule is part of the leaf that is found at the junction of the blade and sheath of the leaf. It may take several forms, but it is commonly some form of translucent membrane or a fringe of hairs. The membranous ligule can be very short 1–2 mm ( Kentucky bluegrass, ''Poa pratensis'') to very long 10–20 mm ( Johnson grass, ''Sorghum halepense''), it can also be smooth on the edge or very ragged. Some grasses do not have a ligule, for example barnyardgrass ('' Echinochloa crus-galli''). A ligule can also be defined as a membrane-like tissue or row of delicate hairs typically found in grasses at the junction of the leaf sheath and blade. ... [...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; Published by Gerald Duckworth & Co. London, 4th ed 1928 Plants Botanically, pinnation is an arrangement of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Albert Setchell
William Albert Setchell (April 15, 1864 – April 5, 1943) was an American botanist and marine phycologist who taught at the University of California, Berkeley, where he headed the Botany Department. Among his publications are the ''Phycotheca Boreali-Americana'', a multi-volume specimen collection of dried algae, and the ''Algae of Northwestern America'', a reference work. Education Setchell was born in Norwich, Connecticut, to George Case Setchell and Mary Ann (Davis) Setchell. Setchell showed an early interest in natural history that was furthered during his years at the Norwich Free Academy. He went to Yale University as an undergraduate and to Harvard University for graduate work, where he studied with William Gilson Farlow, a specialist in cryptogams. He did his thesis work on the anatomy and morphology of kelps. Career After completing his PhD in 1890, Setchell took a post at the Sheffield Scientific School of Yale University as an assistant in biology. He rose to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk (mathematics)
In geometry, a disk (also spelled disc). is the region in a 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'' of center (a, b) and radius ''R'' is given by the formula :D=\ while the ''closed disk'' of the same center and radius is given by :\overline=\. The 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 homeomorphic), as they have different topological properties from each other. For instance, every closed disk is compact whereas every open disk is not compac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
