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Desmidiaceae
The Desmidiaceae are one of four family (biology), families of Charophyta, charophyte green algae in the order (biology), order Desmidiales (desmids).See the National Center for Biotechnology Information, NCBI]webpage on Desmidiaceae Data extracted from the Desmids in the family Desmidiaceae consist of single-celled (sometimes filamentous or colonial), microscopic green algae. Because they are highly symmetrical, attractive, and come in a diversity of forms, they are popular subjects for microscopy, microscopists, both amateur and professional. Within the desmids (Desmidiales), Desmidiaceae contains tens of genera and thousands of species, making it by far the largest family. Desmidiaceae includes some of the largest and most complex desmid genera, such as ''Micrasterias'', ''Cosmarium'', ''Staurastrum'', and ''Euastrum''. Description Desmids are single-celled (sometimes filamentous or colonial) algae, which are generally constricted in the middle, having two identical halves c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrasterias
''Micrasterias'' is a Cell (biology), unicellular green alga of the order Desmidiales. Its species vary in size reaching up to hundreds of microns. ''Micrasterias'' displays a bilateral symmetry, with two mirror image semi-cells joined by a narrow isthmus containing the nucleus of the organism. This dual semi-cell structure is unique to the group of green algae to which ''Micrasterias'' belongs. Each semi-cell contains a single large chloroplast, the site of photosynthesis for ''Micrasterias''. Chloroplasts within Micrasterias contain chlorophyll a and chlorophyll b and the enzymes required for photosynthesis. The sugar created is used to provide energy for the organism or, if not used, taken up by many small round pyrenoids which are embedded in the chloroplast. They convert the sugar to a starch for storage. ''Micrasterias'' can produce both asexually and sexually. Asexual reproduction occurs via mitosis. When this occurs the genetic material of ''Micrasterias'' is duplicated a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmarium
''Cosmarium'' is a large genus of desmids (Desmidiaceae), a group of green algae closely related to the land plants (Embryophyta). Members of this genus are microscopic and found in freshwater habitats around the world. The name ''Cosmarium'' comes from the Greek word κοσμάριον - ''kosmarion'', meaning a small ornament. Description ''Cosmarium'', with few exceptions, consists of single cells and is thus microscopic. Cells are constricted in the middle, giving them a bilobed appearance;Guiry, M.D., John, D.M., Rindi, F. and McCarthy, Y.K. 2007. ''New Survey of Clare Island Volume 6: The Freshwater and Terrestrial Algae.'' Royal Irish Academy. the two halves are called semicells. Cells come in a variety of different shapes. The cell wall may be smooth or ornamented with spines, granules, scrobiculations (pits), or pores. Cells are generally flattened. Cells usually have one or two chloroplasts filling the cell; each chloroplast contains pyrenoids, typically one or two. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinotaenium
''Actinotaenium'' is a genus of green algae, specifically of the Desmidiaceae. It is a freshwater genus, typically found in the benthos of acidic, oligotrophic lakes or ''Sphagnum'' bogs. It has a cosmopolitan distribution. ''Actinotaenium'' consists of solitary cells with two halves, called semicells; cells have a central constriction called an isthmus where the two semicells are joined. Cells are globose, ovoid, cylindrical or pyramidal when viewed from the side, but circular when viewed from the poles. The cell walls are covered in ornamentation such as fine pores, punctae or scrobiculae (pits); the distribution of ornamentation varies by species. Each semicell has a single chloroplast, which is stellate in cross-section and often with complex lobes. Asexual reproduction occurs by vegetative cell division, similar to that of ''Cosmarium''. Sexual reproduction is by conjugation, with zygotes forming between cells. Mature zygospores are quadrate, or globose with smooth walls, pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmidiales
Desmidiales, commonly called the desmids (''Gr.'' ''desmos'', bond or chain), are an order in the Charophyta, a division of green algae in which the land plants ( Embryophyta) emerged. Desmids consist of single-celled (sometimes filamentous or colonial) microscopic green algae. Because desmids are highly symmetrical, attractive, and come in a diversity of forms, they are popular subjects for microscopists, both amateur and professional. The desmids belong to the class Zygnematophyceae. Although they are sometimes grouped together as a single family Desmidiaceae, most classifications recognize three to five families, usually within their own order, Desmidiales. The Desmidiales comprise around 40 genera and 5,000 to 6,000Brook, Alan J., 1981. ''The Biology of Desmids'', page 1. (Berkeley: University of California Press). species, found mostly but not exclusively in fresh water. In general, desmids prefer acidic waters (pH between 4.8 and 7.0), so many species may be found in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmocladium
''Cosmocladium'' is a genus of freshwater green algae, specifically of the Desmidiaceae. Currently there are 7 accepted species, though there are 11 described. The holotype is '' Cosmocladium pulchellum'' Brébisson described in 1856. ''Cosmocladium'' is a colonial organism, consisting of usually up to 16 cells. Colonies may be free-floating or attached to filamentous algae. The cells are typically quite small, consisting of two identical halves called semicells, and are constricted at the isthmus where the semicells are joined. Cells are connected to each other by thin strands (bundles of microfibrils) secreted by special pores near isthmus, forming a branched network. Semicells are ellipsoid or elongate-oval in apical view, with one chloroplast per semicell each containing a central pyrenoid. The cell wall is smooth. A single nucleus is found in the center of each cell. Asexual reproduction occurs by binary cellular division, similar to that of most other desmids, or by fragment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Staurastrum
''Staurastrum'' is a large genus of desmids (Desmidiaceae), a group of green algae closely related to the land plants (Embryophyta). Members of this genus are microscopic and found in freshwater habitats around the world. The name ''Staurastrum'' comes from the Greek roots ''stauron'', meaning "cross", and ''astron'', meaning "star". Description ''Staurastrum'' consists of singular cells with two identical halves, called semicells; in most species, the cell is deeply constricted at the middle, making the division between semicells clear. When viewed from the polar axis, they are biradiate (with two planes of symmetry) or pluriradiate (with more than two planes of symmetry). Biradiate individuals have long, arm-shaped extensions (termed "processes") attached to the main body of the semicells. Pluriradiate individuals may lack these processes. The cell wall is either smooth, or covered with granules or spines. In each semicell there is a chloroplast, usually located axially, with ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euastrum
''Euastrum'' is a genus of green algae of the Desmidiaceae family.See the National Center for Biotechnology Information, NCBIbr>webpage on Euastrum Data extracted from the It lives in acidic waters. Description It is made of two, symmetrical semicells. They are usually longer than wide and are wavy and lobed. On the ends of the semicells, there is a notch. The cell wall A cell wall is a structural layer that surrounds some Cell type, cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, ... may have "protuberances;" however, they are hard to see. References External links * AlgaTerra databaseIndex Nominum Genericorum Desmidiaceae Charophyta genera {{green algae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmidium
''Desmidium'' is a genus of green algae,See the NCBIbr>webpage on Desmidium Data extracted from the the type genus of the family Desmidiaceae. It has a cosmopolitan distribution in acidic, oligotrophic freshwater lakes and bogs. The genus name of ''Desmidium'' is derived from the Greek word 'desmos' (= ribbon, chain or bond). ''Desmidium'' consists of cells with two halves, called semicells; the cells are attached to each other at their ends, forming filaments. The cells can be longer or shorter than wide, with a median constriction (called an isthmus) where the two semicells join; the isthmus distinct or indistinct. Cells are oval or three- to five-angled in apical view; the apex of each cell is either flat or has a narrow process at each angle; cells are attached to each other by the entire apical surface or by the apical processes. The angles may be offset on each semicell, creating a helical pattern along the filament. Cell walls are smooth and covered with pores. Each semi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bambusina
''Bambusina'' is a genus of freshwater green algae in the family Desmidiaceae. ''Bambusina'' is a cosmopolitan genus, typically associated with Acid, acidic and oligotrophic waters. Species of this genus, particularly ''B. borreri'', have been reported in all continents except Antarctica. Description ''Bambusina'' consists of barrel-shaped cells joined end-to-end to form filaments. The cells are elongate (wider than long) and have a shallow median constriction (isthmus) where the two halves (semicells) meet. Cells are biradiate, omniradiate or rarely triradiate in cross section. The cell wall has longitudinal rows of pores, and may sometimes have a row of pointed spines. Each semicell has a single chloroplast which is stellate in cross section, with a central pyrenoid. A nucleus is located in the isthmus. Reproduction Asexual reproduction is via transverse cell division. During cell division, a folded, plicate cell wall is deposited between along the plane of division. In thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
