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Isoetes
''Isoetes'', commonly known as the quillworts, is a genus of lycopod. It is the only living genus in the family Isoetaceae and order Isoetales. , there were about 200 recognized species, with a cosmopolitan distribution mostly in aquatic habitats but with the individual species often scarce to rare. Species virtually identical to modern quillworts have existed since the Jurassic epoch, though the timing of the origin of modern ''Isoetes'' is subject to considerable uncertainty. The name of the genus may also be spelled ''Isoëtes''. The diaeresis (two dots over the e) indicates that the o and the e are to be pronounced in two distinct syllables. Including this in print is optional; either spelling (''Isoetes'' or ''Isoëtes'') is correct. Description Quillworts are mostly aquatic or semi-aquatic in clear ponds and slow-moving streams, though several (e.g. '' I. butleri'', '' I. histrix'' and '' I. nuttallii'') grow on wet ground that dries out in the summer. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoetes Taiwanensis
''Isoetes taiwanensis'' is a species of plant in the family Isoetaceae. It is endemic to Taiwan, and the only species of quillwort there. ''Isoetes taiwanensis'' can now only be found in Menghuan Pond in Yangmingshan National Park. Description ''Isoetes taiwanensis'' is an aquatic plants. The leaves are short and slender, about 5 to 25 centimeters long, with a single vein and containing four air canals. The plant has a corm divided into three to four segments. The roots grow in the muddy bottom of the water. The sporangia grow on the inner side of the leaf base and are differentiated by size. The larger sporangia are ovoid, appearing grayish-white when moist but turning white when dry. The smaller sporangia are gray and oval-shaped. In Taiwan, it grows submersed in shallow ponds for most of the year. During the winter, which is the high water period, ''Isoetes taiwanensis'' can be a submerged plant. In the dry season of summer, it becomes an emergent plant. However, the moist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crassulacean Acid Metabolism
Crassulacean acid metabolism, also known as CAM photosynthesis, is a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions that allows a plant to photosynthesize during the day, but only exchange gases at night. In a plant using full CAM, the stomata in the leaves remain shut during the day to reduce evapotranspiration, but they open at night to collect carbon dioxide () and allow it to diffuse into the mesophyll cells. The is stored as four-carbon malic acid in vacuoles at night, and then in the daytime, the malate is transported to chloroplasts where it is converted back to , which is then used during photosynthesis. The pre-collected is concentrated around the enzyme RuBisCO, increasing photosynthetic efficiency. This mechanism of acid metabolism was first discovered in plants of the family Crassulaceae. Historical background Observations relating to CAM were first made by de Saussure in 1804 in his ''Recherches Chimiques sur la Végétat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoetes Tegetiformans
''Isoetes tegetiformans'', commonly known as mat-forming quillwort or mat-forming Merlin's grass, is an aquatic lycophyte endemic to the U.S. state of Georgia. It grows exclusively in shallow, temporary pools on granite outcrops, often with only 2 cm of soil. Only 7 populations are known to exist, and three of these have been destroyed since the plant's discovery in 1976. The remaining populations are threatened with habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ... due to quarrying, though the species is protected under the U.S. Endangered Species Act. New leaves quickly sprout after fall and winter rains, but during the dry summer months these typically shrivel. References External links Profile at USDA Plants Profile for ''Isoetes tegetiformans'' [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoetes Nuttallii
''Isoetes nuttallii'', or Nuttall's quillwort, is a species of quillwort, a type of lycopod. It is native to shallow waters and other wet habitats of western North America from British Columbia to California. It produces up to 60 pointed, cylindrical, green to gray-green leaves, each 7 to 17 centimeters long. The velum completely covers the spherical sporangia A sporangium (from Late Latin, ; : sporangia) is an enclosure in which spores are formed. It can be composed of a unicellular organism, single cell or can be multicellular organism, multicellular. Virtually all plants, fungus, fungi, and many ot ..., which are 5 millimeters long and 1.5 millimeters wide. The ligule is small and triangular. The megaspores are 400 to 500 micrometers in diameter. The microspores, which are spiny and covered in tubercles, are 28 to 31 micrometers long. References External linksJepson Manual Treatment [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoetales
Isoetales, sometimes also written Isoëtales, is an order of plants in the class Lycopodiopsida. There are about 140-150 living species, all of which are classified in the genus '' Isoetes'' (quillworts), with a cosmopolitan distribution, but often scarce to rare. Living species are mostly aquatic or semi-aquatic, and are found in clear ponds and slowly moving streams. Each leaf is slender and broadens downward to a swollen base up to 5 mm wide where the leaves attach in clusters to a bulb-like, underground corm characteristic of most quillworts. This swollen base also contains male and female sporangia, protected by a thin, transparent covering ( velum), which is used diagnostically to help identify quillwort species. Quillwort species are very difficult to distinguish by general appearance. The best way to identify them is by examining the megaspores under a microscope. '' Isoetes'' are the only living pteridophytes capable of secondary growth. Fossils Some authors i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoetes Butleri
''Isoetes butleri'', commonly known as limestone quillwort, is a species of plant in the quillwort family, a member of the lycophyte The lycophytes, when broadly circumscribed, are a group of vascular plants that include the clubmosses. They are sometimes placed in a division Lycopodiophyta or Lycophyta or in a subdivision Lycopodiophytina. They are one of the oldest lineag ...s. It is native to the eastern United States, where it is scattered and local. It is found almost exclusively on seasonally wet alkaline soils. Common habitats include rocky prairies and glades, most often over limestone. This species is inconspicuous and easily overlooked, due to its superficial similarity to a vegetative grass or sedge. The leaves of ''Isoetes butleri'' die back at the end of spring, when its habitat becomes hot and dry. It is then reduced to a below ground corm. References {{Taxonbar, from=Q17023023 butleri Flora of the Southeastern United States Flora without expected TNC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoetes Histrix
''Isoetes histrix'', the land quillwort, is an aquatic pteridophyte native to the Mediterranean region, northwestern Africa, and the coasts of western Europe northwest to Cornwall. It occurs mainly in temporarily wet habitats, otherwise called vernal pools. The leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ... are 3–8 cm long, and summer-deciduous. It differs from '' Isoetes durieui'' by its large black scales between the leaves, though these are not always present, and a surface of megaspores with tubercles, whereas ''I. durieui'' has a network of ridges. References External linksFlora Europaea: ''Isoetes histrix'' histrix Flora of England Flora of Malta Grasses of Lebanon {{Lycophyte-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoetaceae
Isoetaceae is a family including living quillworts ('' Isoetes'') and comparable extinct herbaceous lycopsids ('' Tomiostrobus''). References External links * * Lycophytes Plant families {{Lycophyte-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycopodiopsida
Lycopodiopsida is a class of vascular plants also known as lycopsids, lycopods, or lycophytes. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching stems bearing simple leaves called microphylls and reproduce by means of spores borne in sporangia on the sides of the stems at the bases of the leaves. Although living species are small, during the Carboniferous, extinct tree-like forms ( Lepidodendrales) formed huge forests that dominated the landscape and contributed to coal deposits. The nomenclature and classification of plants with microphylls varies substantially among authors. A consensus classification for extant (living) species was produced in 2016 by the Pteridophyte Phylogeny Group (PPG I), which places them all in the class Lycopodiopsida, which includes the classes Isoetopsida and Selaginellopsida used in other systems. (See Table 2.) Alternative classification systems have used ranks from di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
