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Polytrichum Hyperboreum
''Polytrichum hyperboreum'' (commonly referred to as Arctic haircap moss"Polytrichum hyperboreum Arctic Haircap Moss".(2022) ''NatureServe Explorer''. Accessed 04-05-2022. https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.126034/Polytrichum_hyperboreum) is a species of moss belonging to the genus ''Polytrichum'', commonly found throughout arctic regions of the world."Polytrichum hyperboreum in Flora of North America" (2008). Published on the Internehttp://efloras.org ccessed 05 April 2022' Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250065138 Members of this dioecious species readily produces sporophytes with their sporophytic structure, consisting of a foot, seta, capsule, and a hairy calyptra, similar to other ''Polytrichum'' species. ''Polytrichum hyperboreum'' is distinguishable by certain unique features of there gametophytic structure that sets them apart from other gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polytrichum
''Polytrichum'' is a genus of mosses — commonly called haircap moss or hair moss — which contains approximately 70 species that cover a cosmopolitan distribution. The genus ''Polytrichum'' has a number of closely related sporophytic characters. The scientific name is derived from the Ancient Greek words ''polys'', meaning "many", and ''thrix'', meaning "hair". This name was used in ancient times to refer to plants with fine, hairlike parts, including mosses, but this application specifically refers to the hairy calyptras found on young sporophytes. A similar naming related to hair appears in Old Norse, ''haddr silfjar'', "hair of Sif", goddess from Norse Mythology, wife of the god Thor. There are two major sections of ''Polytrichum'' species. The first — section ''Polytrichum'' — has narrow, toothed, and relatively erect leaf margins. The other — section ''Juniperifolia'' — has broad, entire, and sharply inflexed leaf margins that enclose the lamellae on the upper lea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dioicy
Dioicy () is a sexual system where archegonia and antheridia are produced on separate gametophytes. It is one of the two main sexual systems in bryophytes. Both dioicous () and monoicous gametophytes produce gametes in gametangia by mitosis rather than meiosis, so that sperm and eggs are genetically identical with their parent gametophyte. Description Dioicy promotes outcrossing. Sexual dimorphism is commonly found in dioicous species. However, according to Bernard Goffinet sexual dimorphism is rare in dioicous moss species. Dioicy is correlated with reduced sporophyte production, due to spatial separation of male and female colonies, scarcity or absence of males. The term dioecy is meaningless for bryophytes because it refers to the sexuality of sporophytes. Nonetheless dioecy and dioicy are comparable in many respects. Etymology The words dioicous and di(o)ecious are derived from οἶκος or οἰκία and δι- (di-), twice, double. (''(o)e'' is the Latin way ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sporophyte
A sporophyte () is the diploid multicellular stage in the life cycle of a plant or alga which produces asexual spores. This stage alternates with a multicellular haploid gametophyte phase. Life cycle The sporophyte develops from the zygote produced when a haploid egg cell is fertilized by a haploid sperm and each sporophyte cell therefore has a double set of chromosomes, one set from each parent. All land plants, and most multicellular algae, have life cycles in which a multicellular diploid sporophyte phase alternates with a multicellular haploid gametophyte phase. In the seed plants, the largest groups of which are the gymnosperms and flowering plants (angiosperms), the sporophyte phase is more prominent than the gametophyte, and is the familiar green plant with its roots, stem, leaves and cones or flowers. In flowering plants the gametophytes are very reduced in size, and are represented by the germinated pollen and the embryo sac. The sporophyte produces spores (hence t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gametophyte
A gametophyte () is one of the two alternation of generations, alternating multicellular organism, multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the Sexual reproduction of plants, sexual phase in the life cycle of plants and algae. It develops sex organs that produce gametes, haploid sex cells that participate in fertilization to form a diploid zygote which has a double set of chromosomes. Cell division of the zygote results in a new diploid multicellular organism, the second stage in the life cycle known as the sporophyte. The sporophyte can produce haploid spores by meiosis that on germination produce a new generation of gametophytes. Algae In some multicellular green algae (''Ulva lactuca'' is one example), red algae and brown algae, sporophytes and gametophytes may be externally indistinguishable (isomorphic). In ''Ulva (genus), Ulv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tundra
In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless mountain tract". There are three regions and associated types of tundra: Arctic tundra, alpine tundra, and Antarctic tundra. Tundra vegetation is composed of dwarf shrubs, sedges, grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline. The tundra soil is rich in nitrogen and phosphorus. The soil also contains large amounts of biomass and decomposed biomass that has been stored as methane and carbon dioxide in the permafrost, making the tundra soil a carbon sink. As global warming heats the ecosystem and causes soil thawing, the permafrost carbon cycle accelerates and releases much of these soil-contained g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polytrichum Commune
''Polytrichum commune'' (also known as common haircap, great golden maidenhair, great goldilocks, common haircap moss, or common hair moss) is a species of moss found in many regions with high humidity and rainfall. The species can be exceptionally tall for a moss with stems often exceeding though rarely reaching , but it is most commonly found at shorter lengths of . It is widely distributed throughout temperate and boreal latitudes in the Northern Hemisphere and also found in Mexico, several Pacific Islands including New Zealand, and also in Australia. It typically grows in bogs, wet heathland and along forest streams. Description ''Polytrichum commune'' is a medium to large moss. It is dark green in colour, but becomes brownish with age. The stems can occur in either loose or quite dense tufts, often forming extensive colonies. The stems are most typically found at lengths of 5 to 10 cm, but can be as short as 2 cm or as long as 70 cm. They range in stiffness f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distal
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabularies for subdisciplines of anatom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossary Of Leaf Morphology
The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular or irregular, may be smooth or bearing hair, bristles or spines. For more terms describing other aspects of leaves besides their overall morphology see the leaf article. The terms listed here all are supported by technical and professional usage, but they cannot be represented as mandatory or undebatable; readers must use their judgement. Authors often use terms arbitrarily, or coin them to taste, possibly in ignorance of established terms, and it is not always clear whether because of ignorance, or personal preference, or because usages change with time or context, or because of variation between specimens, even specimens from the same plant. For example, whether to call leaves on the same tree "acuminate", "lanceolate", or "linear" could ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
