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Sequoioideae
Sequoioideae, popularly known as redwoods, is a subfamily of coniferous trees within the family Cupressaceae. It includes the largest and tallest trees in the world. Description The three redwood subfamily genera are '' Sequoia'' from coastal California and Oregon, '' Sequoiadendron'' from California's Sierra Nevada, and ''Metasequoia'' in China. The redwood species contains the largest and tallest trees in the world. These trees can live for thousands of years. Threats include logging, fire suppression, climate change, illegal marijuana cultivation, and burl poaching. Only two of the genera, ''Sequoia'' and ''Sequoiadendron'', are known for massive trees. Trees of ''Metasequoia'', from the single living species '' Metasequoia glyptostroboides'', are much smaller. Taxonomy and evolution Multiple studies of both morphological and molecular characters have strongly supported the assertion that the Sequoioideae are monophyletic. Most modern phylogenies place ''Sequoia'' as s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cupressaceae
Cupressaceae is a conifer family, the cypress family, with worldwide distribution. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdioecious or (rarely) dioecious trees and shrubs up to tall. The bark of mature trees is commonly orange- to red- brown and of stringy texture, often flaking or peeling in vertical strips, but smooth, scaly or hard and square-cracked in some species. Description The leaves are arranged either spirally, in decussate pairs (opposite pairs, each pair at 90° to the previous pair) or in decussate whorls of three or four, depending on the genus. On young plants, the leaves are needle-like, becoming small and scale-like on mature plants of many genera; some genera and species retain needle-like leaves throughout their lives. Old leaves are mostly not shed individually, but in small sprays of foliage ( cladoptosis); exceptions are leaves on the sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequoiadendron Giganteum
''Sequoiadendron giganteum'' (giant sequoia; also known as giant redwood, Sierra redwood, Sierran redwood, California big tree, Wellingtonia or simply big treea nickname also used by John Muir) is the sole living species in the genus '' Sequoiadendron'', and one of three species of coniferous trees known as redwoods, classified in the family Cupressaceae in the subfamily Sequoioideae, together with ''Sequoia sempervirens'' (coast redwood) and '' Metasequoia glyptostroboides'' (dawn redwood). Giant sequoia specimens are the most massive trees on Earth. The common use of the name ''sequoia'' usually refers to ''Sequoiadendron giganteum'', which occurs naturally only in groves on the western slopes of the Sierra Nevada mountain range of California. The giant sequoia is listed as an endangered species by the IUCN, with fewer than 80,000 trees remaining. Since its last assessment as an endangered species in 2011, it was estimated that another 13–19% of the population (or 9,761–13 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metasequoia
''Metasequoia'', or dawn redwoods, is a genus of fast-growing deciduous trees, one of three species of conifers known as redwoods. The living species ''Metasequoia glyptostroboides'' is native to Lichuan county in Hubei province, China. Although the shortest of the redwoods, it grows to at least in height. Local villagers refer to the original tree from which most others derive as ''Shuǐshān'' (水杉）, or "water fir", which is part of a local shrine. Since its rediscovery in 1944, the dawn redwood has become a popular ornamental, with examples found in various parks in a variety of countries. Together with ''Sequoia sempervirens'' (coast redwood) and ''Sequoiadendron giganteum'' (giant sequoia) of California, ''Metasequoia'' is classified in the Cupressaceae subfamily Sequoioideae. ''M. glyptostroboides'' is the only living species in its genus, but three fossil species are known. Sequoioideae and several other genera have been transferred from the former family Ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metasequoia Glyptostroboides
''Metasequoia glyptostroboides'', the dawn redwood, is a fast-growing, endangered deciduous conifer. It is the sole living species of the genus ''Metasequoia'', one of three genera in the subfamily Sequoioideae of the family Cupressaceae. It now survives only in wet lower slopes and montane river and stream valleys in the border region of Hubei and Hunan provinces and Chongqing municipality in south-central China, notably in Lichuan county in Hubei. Although the shortest of the redwoods, it can grow to in height. In 1941, the genus ''Metasequoia'' was reported by paleobotanist Shigeru Miki as a widely distributed extinct genus based on fossils, before attracting considerable attention a few years later when small populations were found alive in central China. It is a particularly well-known example of a living fossil species. The tree faces considerable risks of extinction in its wild range due to deforestation, however it has been planted extensively in arboreta worldwide, whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequoia Sempervirens
''Sequoia sempervirens'' ()''Sunset Western Garden Book,'' 1995:606–607 is the sole living species of the genus '' Sequoia'' in the cypress family Cupressaceae (formerly treated in Taxodiaceae). Common names include coast redwood, coastal redwood, and California redwood. It is an evergreen, long-lived, monoecious tree living 1,200–2,200 years or more. This species includes the tallest living trees on Earth, reaching up to in height (without the roots) and up to in diameter at breast height. These trees are also among the oldest living things on Earth. Before commercial logging and clearing began by the 1850s, this massive tree occurred naturally in an estimated along much of coastal California (excluding southern California where rainfall is not sufficient) and the southwestern corner of coastal Oregon within the United States. The name sequoia sometimes refers to the subfamily Sequoioideae, which includes ''S. sempervirens'' along with '' Sequoiadendron'' ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequoia (genus)
''Sequoia'' is a genus of redwood coniferous trees in the subfamily Sequoioideae of the family Cupressaceae. The only extant species of the genus is '' Sequoia sempervirens'' in the Northern California coastal forests ecoregion of Northern California and Southwestern Oregon in the United States. The two other genera in the subfamily Sequoioideae, '' Sequoiadendron'' and ''Metasequoia'', are closely related to ''Sequoia''. It includes the tallest trees, as well as the heaviest, in the world. Several extinct species have been named from fossils, including '' Sequoia affinis ''(Western North America), '' Sequoia chinensis'' (no valid reference, identification uncertain) of China, '' Sequoia langsdorfii'' (reclassified as Metasequoia), '' Sequoia dakotensis'' (reclassified as Metasequoia) of South Dakota (Maastrichtian), and ''Sequoia magnifica'' ( petrified wood from the Yellowstone National Park area). Etymology The name ''Sequoia'' was first published as a genus name by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinophyta
Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extant conifers are perennial woody plants with secondary growth. The great majority are trees, though a few are shrubs. Examples include cedars, Douglas-firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews.Campbell, Reece, "Phylum Coniferophyta". Biology. 7th. 2005. Print. P. 595 As of 1998, the division Pinophyta was estimated to contain eight families, 68 genera, and 629 living species. Although the total number of species is relatively small, conifers are ecologically important. They are the dominant plants over large areas of land, most notably the taiga of the Northern Hemisphere, but also in similar cool climates in mountains further south. Boreal conifers have many wintertime ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Athrotaxis
''Athrotaxis'' is a genus of two to three species (depending on taxonomic opinion) of conifers in the cypress family, Cupressaceae. The genus is endemic to western Tasmania, where they grow in high altitude temperate rainforests.Farjon, A. (2005). ''Monograph of Cupressaceae and Sciadopitys''. Royal Botanic Gardens, Kew. Australian Plant Names Index''Athrotaxis''/ref> They are medium-sized evergreen trees, reaching 10–30 m (rarely 40 m) tall and 1-1.5 m trunk diameter. The leaves are scale-like, 3–14 mm long, are borne spirally on the shoots. The cones are globose to oval, 1–3 cm diameter, with 15-35 scales, each scale with 3-6 seeds; they are mature in 7–9 months after pollination, when they open to release the seeds. The male (pollen) cones are small, and shed their pollen in early spring. They are very susceptible to bush fires, and have declined markedly in abundance due to accidental and deliberate fires since the European colonisation of Tasmania. Tax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Gene
A nuclear gene is a gene whose physical DNA nucleotide sequence is located in the cell nucleus of a eukaryote. The term is used to distinguish nuclear genes from genes found in mitochondria or chloroplasts. The vast majority of genes in eukaryotes are nuclear. Endosymbiotic theory Mitochondria and plastids evolved from free-living prokaryotes into current cytoplasmic organelles through endosymbiotic evolution. Mitochondria are thought to be necessary for eukaryotic life to exist. They are known as the cell's powerhouses because they provide the majority of the energy or ATP required by the cell. The mitochondrial genome (mtDNA) is replicated separately from the host genome. Human mtDNA codes for 13 proteins, most of which are involved in oxidative phosphorylation (OXPHOS). The nuclear genome encodes the remaining mitochondrial proteins, which are then transported into the mitochondria. The genomes of these organelles have become far smaller than those of their free-living predece ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexaploid
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 spore ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferns
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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyploidy
Polyploidy is a condition in which the biological cell, cells of an organism have more than one pair of (Homologous chromosome, homologous) chromosomes. Most species whose cells have Cell nucleus, 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 Ploidy, 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 Biological life cycle, life cycles with two alternation of generations, alternating multicellular generations. The gametophyte generation is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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