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Blunt-leaved Pondweed
''Potamogeton obtusifolius'', known as blunt-leaved pondweed, is an aquatic plant in the genus ''Potamogeton''. It grows mainly in mesotrophic to eutrophic lakes, ponds and ditches, rarely in brackish water. It occurs primarily in Central Europe, the British Isles, Fennoscandia and eastern North America. Description Blunt-leaved pondweed grows annually from turions and seed, producing branching plants with slender, flattened stems that have well-developed nodal glands (these appear as two raised bumps on the stem where the leaf attaches). The submerged leaves are long, rather grass-like, sessile, translucent leaves that are 48–85 (rarely up to 100) mm long and 1.5–3.55 mm wide and pale green, often with a very marked reddish or brownish tinge and a pink tinge along the midrib. There are 1–2 lateral veins either side of the midrib. As the name suggests, the leaf tips are rather blunt, though close inspection usually reveals a narrow point at the tip. The stipules ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franz Carl Mertens
Franz Carl Mertens (3 April 1764 – 19 June 1831) was a German botanist who was a native of Bielefeld. He specialized in the field of phycology. Mertens studied theology and languages at the University of Halle, and after graduation taught classes at Bremen Polytechnic College. In his spare time he studied botany, and through a mutual friend met German botanist Albrecht Wilhelm Roth (1757–1834). With Roth, he took scientific expeditions throughout Europe, including Scandinavia. From these trips, Mertens described a number of species of algae. He also performed illustrative work on Volume 3 of Roth's ''Catalecta botanica''. With Erlangen professor Wilhelm Daniel Joseph Koch (1771–1849), he published the third edition of Johann Christoph Röhling's ''Deutschlands flora'', a five volume treatise on German flora. With Friedrich Heinrich Wilhelm Frölich and Johannes Nicolaus von Suhr he issued the exsiccata-like series ''Hydrophytorum tam indigenorum quam exoticorum collect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stipule
In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole (botany), petiole). They are primarily found among dicots and rare among monocots. Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many species they may be inconspicuous —or sometimes entirely absent, and the leaf is then termed ''exstipulate''. At the other end of the scale are species like ''Artocarpus elasticus'' where the stipules can be up to eight inches (twenty cm) in length. (In some older botanical writing, the term "stipule" was used more generally to refer to any small leaves or leaf-parts, notably prophylls.) The word ''stipule'' was coined by Carl Linnaeus, Linnaeus''Concise English Dictionary'' Wordsworth Editions Ltd. 1994, from Latin ''stipula'', straw, stalk. Types of stipules General characteristics The position of stipules on a plant varies widely from species to species, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potamogeton
''Potamogeton'' is a genus of aquatic, mostly freshwater, plants of the family Potamogetonaceae. Most are known by the common name pondweed, although many unrelated plants may be called pondweed, such as Canadian pondweed (''Elodea canadensis''). The genus name means "river neighbor", originating from the Greek ''potamos'' (river) and ''geiton'' (neighbor). Morphology ''Potamogeton'' species range from large (stems of 6 m or more) to very small (less than 10 cm). Height is strongly influenced by environmental conditions, particularly water depth. All species are technically perennial, but some species disintegrate in autumn to a large number of asexually produced resting buds called turions, which serve both as a means of overwintering and dispersal. Turions may be borne on the rhizome, on the stem, or on stolons from the rhizome. Most species, however, persist by perennial creeping rhizomes. In some cases the turions are the only means to differentiate species. The l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chironomid
Chironomidae , commonly known as non-biting midges or chironomids , are a family of Nematoceran flies with a global distribution. They are closely related to the families Ceratopogonidae, Simuliidae, and Thaumaleidae. Although many chironomid species superficially resemble mosquitoes, they can be distinguished by the absence of wing scales and elongated mouthparts characteristic of the Culicidae (true mosquitoes). The name Chironomidae stems from the Ancient Greek word ''kheironómos'', "a pantomimist". Common names and biodiversity This is a large taxon of insects. Some estimates of the species numbers suggest well over 10,000 world-wide. Males are easily recognized by their plumose antennae. Adults are known by a variety of vague and inconsistent common names, largely by confusion with other insects. For example, chironomids are known as "lake flies" in parts of Canada and Lake Winnebago, Wisconsin, but "bay flies" in the areas near the bay of Green Bay, Wisconsin. They ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heilongjiang Province
Heilongjiang is a province in northeast China. It is the northernmost and easternmost province of the country and contains China's northernmost point (in Mohe City along the Amur) and easternmost point (at the confluence of the Amur and Ussuri rivers). The province is bordered by Jilin to the south and Inner Mongolia to the west. It also shares a border with Russia ( Amur Oblast, Jewish Autonomous Oblast, Khabarovsk Krai, Primorsky Krai and Zabaykalsky Krai) to the north and east. The capital and the largest city of the province is Harbin. Among Chinese provincial-level administrative divisions, Heilongjiang is the sixth-largest by total area, the 20th-most populous, and the second-poorest by GDP per capita after only Gansu province. The province takes its name from the Amur river which marks the border between the People's Republic of China and Russia. Heilongjiang has significant agricultural production, and raw materials, such as timber, oil, and coal. Etymology Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potamogeton Compressus
''Potamogeton compressus'' is a species of aquatic plant known by the common names grass-wrack pondweed, flatstem pondweed and eel-grass pondweed. Description ''Potamogeton compressus'' produces a strongly flattened, robust, branching stem up to 90 cm in maximum length. It grows annually from turions and seed, producing bushy plants branching near the surface with long, rather grass-like leaves that are 85–240 mm long and 3–6 mm wide and olive-green or dark green, sometimes with a reddish tinge near the surface. Each leaf has two veins either side of the midrib and is bluntly pointed. The leaves have a rather opaque appearance compared to the transparent leaves of most pondweeds due to the presence of fibres called sclerenchymatous strands. There are no rhizomes or floating leaves. The inflorescences are up to 6 mm long with 4–6 flowers with a short peduncle (5–20 mm long, occasionally more). The fruits are 3.1–4 x 2.1–3 mm. Grass-wrack ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potamogeton Pusillus
''Potamogeton pusillus'' is a species of aquatic plant known by the common names small pondweed, lesser pondweed or least pondweed. It occurs in standing and slow-flowing freshwater habitats throughout the Northern Hemisphere. Description Lesser pondweed is a superficially grasslike herb producing a very slender, branching, somewhat compressed stem, usually less than 70 cm but occasionally up to one metre in length. Nodal glands, if present, are generally poorly developed. The leaves are narrow and linear, translucent, mid or olive green, usually 20–50 mm long × 0.8–1.4 mm wide, but rarely up to 100 mm long and 1.9 mm wide. The midrib often lacks lacunae (transparent areas either side of the midrib) either side of it, and if present, lacunae are restricted to the lower half of the leaf. There are no floating leaves. The stipules are tubular when young, but tend to split with age. Turions are produced, often in large quantities. In early autumn the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potamogeton Berchtoldii
''Potamogeton berchtoldii'', common name small pondweed, is an aquatic plant. Description Small pondweed is a fine-leaved pondweeds with a bushy habit. It lacks a perennial rhizome and the plants die back in winter into a large number of resting buds known as turions. The stems are very slender and do not usually exceed 60 cm. The leaves are flat, usually 25–50 mm long, and less than 2 mm wide, usually with a broad band of lacunae along each side of the midrib and coloured pale green, olive green or brownish green. The open stipules and shining nodal glands can be important characters in identification. Small pondweed is similar to several other ''Potamogeton'' species, especially ''P. pusillus'', and use of a good key such as Preston (1995) is strongly recommended. It could also be confused with ''P. trichoides'' and ''P. obtusifolius''. Taxonomy Small pondweed was first named by the German botanist Franz Xaver Fieber in 1838. It is named after the 19th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sessile (botany)
In botany, sessility (meaning "sitting", in the sense of "resting on the surface") is a characteristic of plant organs such as flowers or leaves that have no stalk. Plant parts can also be described as subsessile, that is, not completely sessile. A sessile flower is one that lacks a pedicel (flower stalk). A flower that is not sessile is pedicellate. For example, the genus ''Trillium'' is partitioned into multiple subgenera, the sessile-flowered trilliums ( ''Trillium'' subgen. ''Sessilia'') and the pedicellate-flowered trilliums. The term "sessility" is also used in mycology to describe a fungal fruit body that is attached to or seated directly on the surface of the substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ..., lacking a supporting stipe or pedicel. Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm Daniel Joseph Koch
Wilhelm Daniel Joseph Koch (5 March 1771 – 14 November 1849) was a German physician and botanist from Kusel, which at various points in his life was under the Holy Roman Empire, part of France and then part of the Kingdom of Bavaria. Education Koch studied medicine at the Universities of University of Jena, Jena and University of Marburg, Marburg, and afterwards was a ''City physician, Stadtphysicus'' (state physician) in Trarbach. He then took the same position at Kaiserslautern in 1798, which would come under French control and then move to Bavarian control as did his home city. In 1824 he became a professor of medicine and botany at the University of Erlangen, where he stayed for the remainder of his life. At Erlangen, he was also director of the botanical gardens. In 1833, he was elected a foreign member of the Royal Swedish Academy of Sciences. Death Koch died in Erlangen. Notable works Among his better written efforts was a synopsis on German and Swiss flora titled ''Sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turion (botany)
A turion (from Latin turio meaning "shoot") is a type of bud that is capable of growing into a complete plant. A turion may be an underground bud. Many members of the genus '' Epilobium'' are known to produce turions at or below ground level. Some aquatic plant species produce overwintering turions, especially in the genera '' Potamogeton'', '' Myriophyllum'', '' Aldrovanda'' and '' Utricularia''. These plants produce turions in response to unfavourable conditions such as decreasing day-length or reducing temperature. They are derived from modified shoot apices and are often rich in starch and sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecul ...s enabling them to act as storage organs. Although they are hardy ( frost resistant), it is probable that their principal adap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brackish
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root '' brak''. Certain human activities can produce brackish water, in particular civil engineering projects such as dikes and the flooding of coastal marshland to produce brackish water pools for freshwater prawn farming. Brackish water is also the primary waste product of the salinity gradient power process. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it can be damaging to the environment (see article on shrimp farms). Technically, brackish water contains between 0.5 and 30 grams of salt per litre—more often expressed as 0.5 to 30 parts per thousand (‰), which is a spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
