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Pellaea Glabella
''Pellaea glabella'' is a fern with the common name smooth cliffbrake. It was once regarded as a reduced form or variety of ''Pellaea atropurpurea''. ''P. glabella'' is known to exist in two cryptic species, one diploid and one tetraploid. The diploid reproduces sexually, while the tetraploid is normally apogamous. It is now known that the tetraploid form of the species is one of the parents of the original hybrid ''P.'' × ''atropurpurea'' that became the apogamous species. Range and Habitat ''P. glabella'' ranges widely in the United States and much of Canada, excluding the northernmost regions and Alaska. ''P. glabella'' is epipetric, normally growing on well-weathered limestone, usually in cracks with little or no soil. It can also be found on sandstone and basalt, probably in places where calcium is locally concentrated. It favors more exposed sites than ''P. atropurpurea''. Description This species has sessile or nearly sessile pinnae. Sori are formed on the u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mett
Mett is a preparation of minced (ground) raw pork seasoned with salt and black pepper that is popular in Germany and Poland. It is frequently spread on halves of a bread roll, with raw onion optionally on top. Since the 1950s Mett has also been offered as a buffet dish decoratively formed into the shape of a hedgehog, with raw onion "spines". German law forbids mett being sold with a fat content exceeding 35%. Description The name is derived from Low German ''mett'' for "chopped pork meat without bacon", or Old Saxon ''meti'' for "food". It is also known as Hackepeter (Northern Germany, Eastern Germany, Bavaria and Berlin). It consists of minced pork meat, normally seasoned with salt and black pepper, regionally also with garlic or caraway, and eaten raw. It is also permitted to add chopped onion, in which case and it is known as ''Zwiebelmett'' (onion Mett). Legally, German Mett is not allowed to contain more than 35% fat. Unless pre-packaged, the German ''Lebensmittelhygiene-V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Friedrich Adalbert Maximilian Kuhn
Friedrich Adalbert Maximilian Kuhn (3 December 1842 – 13 September 1894) was a German botanist, who specialized in the field of pteridology. He went by the name "Max," and his name was often written "Maximilian Friedrich Adalbert Kuhn." He studied natural sciences at Berlin, where his influences included Alexander Braun. While still a student, he took part in a botanical trip to the Carpathians under the direction of Paul Friedrich August Ascherson Paul Friedrich August Ascherson (June 4, 1834 – March 6, 1913) was a German botanist. His author citation is ''Asch.'', although ''Aschers.'' has been used in the past. Ascherson was born in Berlin in 1834 as the son of health counsellor. In 1 .... From 1870 onward, he taught classes at the ''Konigstadtische Realschule'' (later gymnasium) in Berlin. In 1889 he received the title of professor. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pellaea Atropurpurea
''Pellaea atropurpurea'', commonly known as purple-stem cliffbrake or just purple cliffbrake, is a fern native to North and Central America. ''Brake'' is an old word for fern, related to the word ''bracken''. Like many other members of the Pteridaceae, it is a rock plant, needing a calcareous substrate. ''P. atropurpurea'' is an apogamous autotriploid, with ''3n=87'' (actual base number, ''n=29''), and is one of the historical parents of the hybrid species complex, '' Pellaea glabella''. Apogamy, or the ability to reproduce non-sexually, is common among rock ferns in the Pteridaceae. Characteristics This fern produces clumps of widely arching fronds. The stipe and rachis of the blade are purple, while the blade itself has a blue-gray tinge to it. The upper pinnae are long, narrow, and undivided, while the lower ones are divided into 3–15 pinnules. The pinnae are, for the most part, opposite. Fertile fronds are longer and more heavily divided. They produce sori, which lack ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diploid
Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively, in each homologous chromosome pair, which chromosomes naturally exist as. Somatic cells, tissues, and individual organisms can be described according to the number of sets of chromosomes present (the "ploidy level"): monoploid (1 set), diploid (2 sets), triploid (3 sets), tetraploid (4 sets), pentaploid (5 sets), hexaploid (6 sets), heptaploid or septaploid (7 sets), etc. The generic term polyploid is often used to describe cells with three or more chromosome sets. Virtually all sexually reproducing organisms are made up of somatic cells that are diploid or greater, but ploidy level may vary widely between different organisms, between different tissues within the same organism, and at different stages in an organism's life cycle. Half ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetraploid
Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains one or more chromosomes and comes from each of two parents, resulting in pairs of homologous chromosomes between sets. However, some organisms are polyploid. Polyploidy is especially common in plants. Most eukaryotes have diploid somatic cells, but produce haploid gametes (eggs and sperm) by meiosis. A monoploid has only one set of chromosomes, and the term is usually only applied to cells or organisms that are normally diploid. Males of bees and other Hymenoptera, for example, are monoploid. Unlike animals, plants and multicellular algae have life cycles with two alternating multicellular generations. The gametophyte generation is haploid, and produces gametes by mitosis, the sporophyte generation is diploid and produces spores by meio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apogamy
In botany, apomixis is asexual reproduction without fertilization. Its etymology is Greek for "away from" + "mixing". This definition notably does not mention meiosis. Thus "normal asexual reproduction" of plants, such as propagation from cuttings or leaves, has never been considered to be apomixis, but replacement of the seed by a plantlet or replacement of the flower by bulbils were categorized as types of apomixis. Apomictically produced offspring are genetically identical to the parent plant. Some authors included all forms of asexual reproduction within apomixis, but that generalization of the term has since died out. In flowering plants, the term "apomixis" is commonly used in a restricted sense to mean agamospermy, i.e., clonal reproduction through seeds. Although agamospermy could theoretically occur in gymnosperms, it appears to be absent in that group. Apogamy is a related term that has had various meanings over time. In plants with independent gametophytes (notably ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for limes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferns Of The United States
A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except the lycopods, and differ from mosses and other bryophytes by being vascular, i.e., having specialized tissues that conduct water and nutrients and in having life cycles in which the branched sporophyte is the dominant phase. Ferns have complex leaves called megaphylls, that are more complex than the microphylls of clubmosses. Most ferns are leptosporangiate ferns. They produce coiled fiddleheads that uncoil and expand into fronds. The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the Polypodiopsida, comprising both the leptosporangiate (Polypodiidae) and eusporangiate ferns, the latter group including horsetails, whisk ferns, marattioid ferns, and ophioglossoid ferns. Ferns ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flora Of The Southwestern United States
Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous) native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms ''gut flora'' or '' skin flora''. Etymology The word "flora" comes from the Latin name of Flora, the goddess of plants, flowers, and fertility in Roman mythology. The technical term "flora" is then derived from a metonymy of this goddess at the end of the sixteenth century. It was first used in poetry to denote the natural vegetation of an area, but soon also assumed the meaning of a work cataloguing such vegetation. Moreover, "Flora" was used to refer to the flowers of an artificial garden in the seventeenth century. The distinction between vegetation (the general appearance of a community) and flora (the taxonomic composition of a community) was first made by Jules Thurmann (1849). Prior to this, the two terms were used indiscriminately.Thurmann, J. (1849). ''Essai de Phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flora Of The Eastern United States
Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous) native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms ''gut flora'' or '' skin flora''. Etymology The word "flora" comes from the Latin name of Flora, the goddess of plants, flowers, and fertility in Roman mythology. The technical term "flora" is then derived from a metonymy of this goddess at the end of the sixteenth century. It was first used in poetry to denote the natural vegetation of an area, but soon also assumed the meaning of a work cataloguing such vegetation. Moreover, "Flora" was used to refer to the flowers of an artificial garden in the seventeenth century. The distinction between vegetation (the general appearance of a community) and flora (the taxonomic composition of a community) was first made by Jules Thurmann (1849). Prior to this, the two terms were used indiscriminately.Thurmann, J. (1849). ''Essai de Phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flora Of The Great Lakes Region (North America)
Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous) native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms '' gut flora'' or '' skin flora''. Etymology The word "flora" comes from the Latin name of Flora, the goddess of plants, flowers, and fertility in Roman mythology. The technical term "flora" is then derived from a metonymy of this goddess at the end of the sixteenth century. It was first used in poetry to denote the natural vegetation of an area, but soon also assumed the meaning of a work cataloguing such vegetation. Moreover, "Flora" was used to refer to the flowers of an artificial garden in the seventeenth century. The distinction between vegetation (the general appearance of a community) and flora (the taxonomic composition of a community) was first made by Jules Thurmann (1849). Prior to this, the two terms were used indiscriminately.Thurmann, J. (1849). ''Essai de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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