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Posidonia
''Posidonia'' is a genus of flowering plants. It contains nine species of marine plants ("seagrass"), found in the seas of the Mediterranean and around the south coast of Australia. The APG system (1998) and APG II system (2003) accept this genus as constituting the sole genus in the family Posidoniaceae, which it places in the order Alismatales, in the clade monocots. The AP-Website concludes that the three families Cymodoceaceae, Posidoniaceae and Ruppiaceae form a monophyletic group. Earlier systems classified this genus in the family Potamogetonaceae or in the family Posidoniaceae but belonging to order Zosterales. ''Posidonia oceanica'' has nitrogen fixation capabilities via symbiosis and other species may as well. Species This is a list of species that are contained by the genus: *'' Posidonia angustifolia'' Cambridge and Kuo *'' Posidonia australis'' Hook.f. South coast of Australia. *'' Posidonia coriacea'' Cambridge and Kuo *'' Posidonia denhartogii'' Kuo and C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posidonia Oceanica
''Posidonia oceanica'', commonly known as Neptune grass or Mediterranean tapeweed, is a seagrass species that is endemic to the Mediterranean Sea. It forms large underwater meadows that are an important part of the ecosystem. The fruit is free floating and known in Italy as "the olive of the sea" (''l'oliva di mare''). Balls of fibrous material from its foliage, known as ''egagropili'' or ''Neptune balls'', wash up to nearby shorelines. ''Posidonia'' has a very high carbon absorption capacity, being able to soak up 15 times more carbon dioxide every year than a similar sized piece of the Amazon rainforest. Morphology ''Posidonia oceanica'' has roots (which mainly serve to anchor the plant to the substrate), rhizome and tapeform leaves. The rhizomes, up to 1 cm thick, grow both horizontally (plagiotropic rhizomes), and vertically (orthotropic rhizomes). The former, thanks to the presence at the bottom of lignited roots up to 15 cm long, anchor the plant to the subs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seagrass
Seagrasses are the only flowering plants which grow in marine (ocean), marine environments. There are about 60 species of fully marine seagrasses which belong to four Family (biology), families (Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae), all in the order Alismatales (in the clade of monocotyledons). Seagrasses evolved from terrestrial plants which recolonised the ocean 70 to 100 million years ago. The name ''seagrass'' stems from the many species with long and narrow Leaf, leaves, which grow by rhizome extension and often spread across large "Seagrass meadow, meadows" resembling grassland; many species superficially resemble terrestrial grasses of the family Poaceae. Like all autotrophic plants, seagrasses photosynthesize, in the submerged photic zone, and most occur in shallow and sheltered coastal waters anchored in sand or mud bottoms. Most species undergo submarine pollination and complete their life cycle underwater. While it was previously believed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posidonia Australis
''Posidonia australis'', also known as fibre-ball weed or ribbon weed, is a species of seagrass that occurs in the southern waters of Australia. It forms large meadows important to environmental conservation. Balls of decomposing detritus from the foliage are found along nearby shore-lines. In 2022, a single stand in Shark Bay was reported by scientists to not only be the largest plant in the world, but the largest organism by square size. Description ''Posidonia australis'' is a flowering plant occurring in dense meadows, or along channels, in white sand. It is found at depths from . Subsurface rhizomes and roots provide stability in the sands it occupies. Erect rhizomes and leaves reduce the accumulation of silt. The leaves are ribbon-like and wide. They are bright green, perhaps becoming browned with age. The terminus of the leaf is rounded or absent through damage. They are arranged in groups with older leaves on the outside, longer and differing in form from the younger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posidonia Coriacea
''Posidonia coriacea'' is a species of seagrass that occurs in the southern waters of Australia. Description A species of ''Posidonia''. A perennial rhizomatous herb that appears as stands in marine habitat. This species is found at depths from 1 to 30 metres on white sands, in areas subject to intense wave action. The leaf blades are 2.5 to 7 millimetres wide, and 1.25 metres long. Two or three leaves, with large bases, appear from each shoot. They are leathery and thickened convexly on the upper and lower surfaces. Between 7 and 11 veins appear on each leaf. The leaf sheath breaks into strips, rather than the fibrous detritus of similar species. The flowering period is primarily during the months of August and September. Distribution ''Posidonia coriacea'' is recorded at Shark Bay, Western Australia, around coasts of Southwest Australia, and across the Bight to South Australia. Taxonomy This species is contained by the ''Posidoniaceae'' family, one of eight occurring in sou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruppiaceae
''Ruppia'', also known as the widgeonweeds, ditch grasses or widgeon grass, is the only extant genus in the family Ruppiaceae, with 11 known species. These are aquatic plants widespread over much of the world. The genus name honours Heinrich Bernhard Rupp, a German botanist (1688–1719). They are widespread outside of frigid zones and the tropics. Description The leaf is simple and not rhizomatous. They can be annual (commonly) or perennial (rarely); stem growth is conspicuously sympodial, but sometimes is not. These species are adapted to be in brackish water (and salt marshes). The leaves are small or medium-sized. Their disposition can be alternate, opposite, or whorled (usually alternate except when subtending an inflorescence). Even, lamina keep entire and are setaceous or linear. The leaf just shows one vein without cross-venules. Stomata are not present. The mesophyll leaks calcium oxalate crystals. The minor leaf veins do not present phloem transfer cells and leaks ves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cymodoceaceae
Cymodoceaceae is a family of flowering plants, sometimes known as the "manatee-grass family", which includes only marine species. The 2016 APG IV does recognize Cymodoceaceae and places it in the order Alismatales, in the clade monocots. The family includes five genera, totaling 17 species occurring in tropical seas and oceans (so-called seagrasses). According to thAP-Websiteit is doubtful if the family Ruppiaceae is distinct enough to be kept apart. The inclusion of the sole genus ''Ruppia'' in Ruppiaceae in Cymodoceaceae is being considered. The plants in the three families Cymodoceaceae, Posidoniaceae and Ruppiaceae form a monophyletic group. Its fossil record shows that Cymodoceaceae was established in its current Indo-West Pacific distribution by the early Eocene and perhaps even during the late Paleocene. Fossils of ''Thalassodendron auriculalopris'' den Hartog and ''Cymodocea floridana'' den Hartog (both extant) were also found in west-central Florida and date ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potamogetonaceae
The Potamogetonaceae, commonly referred to as the pondweed family, is an aquatic family of monocotyledonous flowering plants. The roughly 110 known species are divided over five genera. The largest genus in the family by far is '' Potamogeton'', which contains about 100 species. The family has a subcosmopolitan distribution, and is considered to be one of the most important angiosperm groups in the aquatic environment because of its use as food and habitat for aquatic animals.Haynes, R. R. 1975. A revision of North American ''Potamogeton'' subsection Pusilli (Potamogetonaceae). Rhodora 76: 564--64 Taxonomy The Potamogetonaceae are currently placed in the early diverging monocot order Alismatales by the Angiosperm Phylogeny Group. Their concept of the family includes the plants sometimes treated in the separate family Zannichelliaceae, but excludes the genus '' Ruppia''. So circumscribed, the family currently consists of five genera totalling about 120 species of perennial aqua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alismatales
The Alismatales (alismatids) are an order of flowering plants including about 4,500 species. Plants assigned to this order are mostly tropical or aquatic. Some grow in fresh water, some in marine habitats. Perhaps the most important food crop in the order is the taro plant, ''Colocasia esculenta''. Description The Alismatales comprise herbaceous flowering plants of often aquatic and marshy habitats, and the only monocots known to have green embryos other than the Amaryllidaceae. They also include the only marine angiosperms growing completely submerged, the seagrasses. The flowers are usually arranged in inflorescences, and the mature seeds lack endosperm. Both marine and freshwater forms include those with staminate flowers that detach from the parent plant and float to the surface. There they can pollinate carpellate flowers floating on the surface via long pedicels. In others, pollination occurs underwater, where pollen may form elongated strands, increasing chance of suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Fixation
Nitrogen fixation is a chemical process by which molecular dinitrogen () is converted into ammonia (). It occurs both biologically and abiological nitrogen fixation, abiologically in chemical industry, chemical industries. Biological nitrogen fixation or ''diazotrophy'' is catalyzed by enzymes called nitrogenases. These enzyme complexes are encoded by the Nif gene, ''Nif'' genes (or ''Nif'' homologs) and contain iron, often with a second metal (usually molybdenum, but sometimes vanadium). Some nitrogen-fixing bacteria have symbiotic relationships with plants, especially legumes, mosses and aquatic ferns such as ''Azolla''. Looser non-symbiotic relationships between diazotrophs and plants are often referred to as associative, as seen in nitrogen fixation on rice roots. Nitrogen fixation occurs between some termites and fungus, fungi. It occurs naturally in the air by means of NOx, NOx production by lightning. Fixed nitrogen is essential to life on Earth. Organic compounds such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
