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Mountain Avens
''Dryas octopetala'', the mountain avens, eightpetal mountain-avens, white dryas or white dryad, is an Arctic–alpine flowering plant in the family Rosaceae. It is a small prostrate evergreen subshrub forming large colonies. The specific epithet ''octopetala'' derives from Greek ''octo'' 'eight' and ''petalon'' ' petal', referring to the eight petals of the flower, an unusual number in the Rosaceae, where five is the normal number. However, flowers with up to 16 petals also occur naturally. As a floral emblem, it is the official territorial flower of the Northwest Territories and the national flower of Iceland. Description The stems are woody, tortuous, with short, horizontal rooting branches. The leaves are glabrous above, densely white-tomentose beneath. The flowers are produced on stalks long, and have eight creamy white petals – hence the specific epithet ''octopetala''. The style is persistent on the fruit with white feathery hairs, functioning as a wind-dispersal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern Taxonomy (biology), taxonomy". Many of his writings were in Latin; his name is rendered in Latin as and, after his 1761 ennoblement, as . Linnaeus was born in Råshult, the countryside of Småland, in southern Sweden. He received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and also published the first edition of his ' in the Netherlands. He then returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Botanical Name
A botanical name is a formal scientific name conforming to the ''International Code of Nomenclature for algae, fungi, and plants'' (ICN) and, if it concerns a plant cultigen, the additional cultivar or Group epithets must conform to the ''International Code of Nomenclature for Cultivated Plants'' (ICNCP). The code of nomenclature covers "all organisms traditionally treated as algae, fungi, or plants, whether fossil or non-fossil, including blue-green algae (Cyanobacteria), chytrids, oomycetes, slime moulds and photosynthetic protists with their taxonomically related non-photosynthetic groups (but excluding Microsporidia)." The purpose of a formal name is to have a single name that is accepted and used worldwide for a particular plant or plant group. For example, the botanical name ''Bellis perennis'' denotes a plant species which is native to most of the countries of Europe and the Middle East, where it has accumulated various names in many languages. Later, the plant was introduc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock Garden
A rock garden, also known as a rockery and formerly as a rockwork, is a garden, or more often a part of a garden, with a landscaping framework of rocks, stones, and gravel, with planting appropriate to this setting. Usually these are small Alpine plants that need relatively little soil or water. Western rock gardens are often divided into alpine gardens, scree gardens on looser, smaller stones, and other rock gardens. Some rock gardens are planted around natural outcrops of rock, perhaps with some artificial landscaping, but most are entirely artificial, with both rocks and plants brought in. Some are designed and built to look like natural outcrops of bedrock. Stones are aligned to suggest a bedding plane, and plants are often used to conceal the joints between said stones. This type of rockery was popular in Victorian times and usually created by professional landscape architects. The same approach is sometimes used in commercial or modern-campus landscaping but can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundcover
Groundcover or ground cover is any plant that grows over an area of ground. Groundcover provides protection of the topsoil from erosion and drought. In an ecosystem, the ground cover forms the layer of vegetation below the shrub layer known as the herbaceous layer. The most widespread ground covers are grasses of various types. In ecology, groundcover is a difficult subject to address because it is known by several different names and is classified in several different ways. The term groundcover could also be referring to “the herbaceous layer,” “regenerative layer", “ground flora” or even "step over." In agriculture, ground cover refers to anything that lies on top of the soil and protects it from erosion and inhibits weeds. It can be anything from a low layer of grasses to a plastic material. The term ''ground cover'' can also specifically refer to landscaping fabric which is like a breathable tarp that allows water and gas exchange. In gardening jargon, however, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperateness
In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout the year and more distinct seasonal changes compared to tropical climates, where such variations are often small and usually only have precipitation changes. In temperate climates, not only do latitudinal positions influence temperature changes, but sea currents, prevailing wind direction, continentality (how large a landmass is) and altitude also shape temperate climates. The Köppen climate classification defines a climate as "temperate" C, when the mean temperature is above but below in the coldest month to account for the persistency of frost. However, other climate classifications set the minimum at . Zones and climates The north temperate zone extends from the Tropic of Cancer (approximately 23.5° north latitude) to the Arct ... [...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-containe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forest
A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' Food and Agriculture Organization (FAO) defines a forest as, "Land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover of more than 10 percent, or trees able to reach these thresholds ''in situ''. It does not include land that is predominantly under agricultural or urban use." Using this definition, '' Global Forest Resources Assessment 2020'' (FRA 2020) found that forests covered , or approximately 31 percent of the world's land area in 2020. Forests are the predominant terrestrial ecosystem of Earth, and are found around the globe. More than half of the world's forests are found in only five countries (Brazil, Canada, China, Russia, and the United States). The largest share of forests (45 percent) are in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Hemisphere
The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's North Pole. Owing to Earth's axial tilt of 23.439281°, winter in the Northern Hemisphere lasts from the December solstice (typically December 21 UTC) to the March equinox (typically March 20 UTC), while summer lasts from the June solstice through to the September equinox (typically on 23 September UTC). The dates vary each year due to the difference between the calendar year and the astronomical year. Within the Northern Hemisphere, oceanic currents can change the weather patterns that affect many factors within the north coast. Such events include El Niño–Southern Oscillation. Trade winds blow from east to west just above the equator. The winds pull surface water with them, creating currents, which flow westward due to the Corio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollen
Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophytes during the process of their movement from the stamens to the pistil of flowering plants, or from the male cone to the female cone of gymnosperms. If pollen lands on a compatible pistil or female cone, it germinates, producing a pollen tube that transfers the sperm to the ovule containing the female gametophyte. Individual pollen grains are small enough to require magnification to see detail. The study of pollen is called palynology and is highly useful in paleoecology, paleontology, archaeology, and forensics. Pollen in plants is used for transferring haploid male genetic material from the anther of a single flower to the stigma of another in cross-pollination. In a case of self-pollination, this process takes place from the an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stadial
Stadials and interstadials are phases dividing the Quaternary period, or the last 2.6 million years. Stadials are periods of colder climate while interstadials are periods of warmer climate. Each Quaternary climate phase is associated with a Marine Isotope Stage (MIS) number, which describe alternation between warmer and cooler temperatures as measured by oxygen isotope data. Stadials have even MIS numbers and interstadials odd MIS numbers. The current Holocene interstadial is MIS 1 and the Last glacial maximum stadial is MIS 2. Marine Isotope Stages are sometimes further subdivided into stadials and interstadials by minor climate fluctuations within the overall stadial or interstadial regime, which are indicated by letters. The odd-numbered interstadial MIS 5, also known as the Sangamonian interglacial, contains two periods of relative cooling, and so is subdivided into three interstadials (5a, 5c, 5e) and two stadials (5b, 5d). A stadial isotope stage like MIS 6 would be su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oldest Dryas
The Oldest Dryas is a biostratigraphic subdivision layer corresponding to a relatively abrupt climatic cooling event, or stadial, which occurred during the last glacial retreat. The time period to which the layer corresponds is poorly defined and varies between regions, but it is generally dated as starting at 18.5–17 thousand years ( ka) before present (BP) and ending 15–14 ka BP. As with the Younger and Older ''Dryas'' events, the stratigraphic layer is marked by abundance of the pollen and other remains of ''Dryas octopetala'', an indicator species that colonizes arctic-alpine regions. In the Alps, the Oldest Dryas corresponds to the Gschnitz stadial of the Würm glaciation. The term was originally defined specifically for terrestrial records in the region of Scandinavia, but has come to be used both for ice core stratigraphy in areas across the world, and to refer to the time period itself and its associated temporary reversal of the glacial retreat. Flora Durin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Older Dryas
The Older Dryas was a stadial (cold) period between the Bølling and Allerød interstadials (warmer phases), about 14,000 years Before Present, towards the end of the Pleistocene. Its date is not well defined, with estimates varying by 400 years, but its duration is agreed to have been around 200 years. The gradual warming since the Last Glacial Maximum (27,000 to 24,000 years BP) has been interrupted by two cold spells: the Older Dryas and the Younger Dryas (c. 12,900–11,650 BP). In northern Scotland, the glaciers were thicker and deeper during the Older Dryas than the succeeding Younger Dryas, and there is no evidence of human occupation of Britain. In Northwestern Europe there was also an earlier Oldest Dryas (18.5–17 ka BP 15–14 ka BP). The Dryas are named after an indicator genus, the Arctic and Alpine plant Dryas, the remains of which are found in higher concentrations in deposits from colder periods. The Older Dryas was a variable cold, dry Blytt–Sernander ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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