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Marcescence
Marcescence is the withering and persistence of plant organs that normally are shed, and is a term most commonly applied to plant leaves. The underlying physiological mechanism is that trees transfer water and sap from the roots to the leaves through their vascular cells, but in some trees as autumn begins, the veins carrying the sap slowly close until a layer of cells called the abscission layer completely closes off the vein allowing the tree to rid itself of the leaf. Leaf marcescence is most often seen on juvenile plants and may disappear as the tree matures. It also may not affect the entire tree; sometimes leaves persist only on scattered branches. Marcescence is most obvious in deciduous trees that retain leaves through the winter. Trees that exhibit marcescence are known as "everciduous". Several trees normally have marcescent leaves such as oak (''Quercus''), beech (''Fagus'') and hornbeam (''Carpinus''), or marcescent stipules as in some but not all species of willows ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marasmius
''Marasmius'' is a genus of mushroom-forming fungi in the family Marasmiaceae. It contains about 500 species of agarics, of which a few, such as '' Marasmius oreades'', are edible. However, most members of this genus are small, unimpressive brown mushrooms. Their humble appearance contributes to their not being readily distinguishable to non-specialists, and they are therefore seldom collected by mushroom hunters. Several of the species are known to grow in the characteristic fairy ring pattern. The author of the genus was Elias Magnus Fries, who in 1838 classified white-spored agarics having a tough central stipe in this taxon if they were marcescent, i.e. they could dry out but later revive when moistened. For Fries, marcescence — by contrast with the " putrescent" (decomposing) nature of most mushrooms — was an important character for classification, which he used to separate this group from genus '' Collybia'' (which has now been split into many newer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deciduous
In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, after flowering; and to the shedding of ripe fruit. The antonym of ''deciduous'' in the botanical sense is evergreen. Generally, the term "deciduous" means "the dropping of a part that is no longer needed or useful" and the "falling away after its purpose is finished". In plants, it is the result of natural processes. "Deciduous" has a similar meaning when referring to animal parts, such as deciduous antlers in deer, deciduous teeth (baby teeth) in some mammals (including humans); or decidua, the uterine lining that sheds off after birth. Botany In botany and horticulture, deciduous plants, including trees, shrubs and herbaceous perennials, are those that lose all of their leaves for part of the year. This process is called a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salix
Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions. Most species are known as willow, but some narrow-leaved shrub species are called osier, and some broader-leaved species are referred to as sallow (from Old English ''sealh'', related to the Latin word ''salix'', willow). Some willows (particularly arctic and alpine species) are low-growing or creeping shrubs; for example, the dwarf willow (''Salix herbacea'') rarely exceeds in height, though it spreads widely across the ground. Description Willows all have abundant watery bark sap, which is heavily charged with salicylic acid, soft, usually pliant, tough wood, slender branches, and large, fibrous, often stoloniferous roots. The roots are remarkable for their toughness, size, and tenacity to live ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pin Oak
''Quercus palustris'', the pin oak or swamp Spanish oak, is a tree in the red oak section (''Quercus'' sect. ''Lobatae'') of the genus ''Quercus''. Pin oak is one of the most commonly used landscaping oaks in its native range due to its ease of transplant, relatively fast growth, and pollution tolerance. Description Pin oak is a medium-sized deciduous tree growing to tall, with a trunk up to in diameter. It has an spread. A 10-year-old tree grown in full sun will be about tall. Young trees have a straight, columnar trunk with smooth bark and a pyramidal canopy. By the time the tree is 40 years old, it develops more rough bark with a loose, spreading canopy. This canopy is considered one of the most distinctive features of the pin oak: the upper branches point upwards, the middle branches are at right angles to the trunk, and the lower branches droop downwards. The leaves are long and broad, lobed, with five or seven lobes. Each lobe has five to seven bristle-tipped tee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Litter
Plant litter (also leaf litter, tree litter, soil litter, litterfall or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that have fallen to the ground. This detritus or dead organic material and its constituent nutrients are added to the top layer of soil, commonly known as the litter layer or O horizon ("O" for "organic"). Litter is an important factor in ecosystem dynamics, as it is indicative of ecological productivity and may be useful in predicting regional nutrient cycling and soil fertility. Characteristics and variability Litterfall is characterized as fresh, undecomposed, and easily recognizable (by species and type) plant debris. This can be anything from leaves, cones, needles, twigs, bark, seeds/nuts, logs, or reproductive organs (e.g. the stamen of flowering plants). Items larger than 2 cm diameter are referred to as coarse litter, while anything smaller is referred to as fine litter or litter. The type of litterfall i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photodegradation
Photodegradation is the alteration of materials by light. Commonly, the term is used loosely to refer to the combined action of sunlight and air, which cause oxidation and hydrolysis. Often photodegradation is intentionally avoided, since it destroys paintings and other artifacts. It is, however, partly responsible for remineralization of biomass and is used intentionally in some disinfection technologies. Photodegradation does not apply to how materials may be aged or degraded via infrared light or heat, but does include degradation in all of the ultraviolet light wavebands. Applications Foodstuffs The protection of food from photodegradation is very important. Some nutrients, for example, are affected by degradation when exposed to sunlight. In the case of beer, UV radiation causes a process that entails the degradation of hop bitter compounds to 3-methyl-2-buten-1-thiol and therefore changes the taste. As amber-colored glass has the ability to absorb UV radiation, beer bottles ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Growth Form
Plant life-form schemes constitute a way of classifying plants alternatively to the ordinary species-genus-family scientific classification. In colloquial speech, plants may be classified as trees, shrubs, herbs (forbs and graminoids), etc. The scientific use of life-form schemes emphasizes plant function in the ecosystem and that the same function or "adaptedness" to the environment may be achieved in a number of ways, i.e. plant species that are closely related phylogenetically may have widely different life-form, for example '' Adoxa'' and ''Sambucus'' are from the same family, but the former is a small herbaceous plant and the latter is a shrub or tree. Conversely, unrelated species may share a life-form through convergent evolution. While taxonomic classification is concerned with the production of natural classifications (being natural understood either in philosophical basis for pre-evolutionary thinking, or phylogenetically as non-polyphyletic), plant life form classific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Espeletia
''Espeletia'', commonly known as 'frailejones' ("big monks"), is a genus of perennial subshrubs, in the family Asteraceae. The genus, which is native mainly to Colombia, Venezuela and Ecuador, was first formally described in 1808. The genus was named after the viceroy of New Granada, José Manuel de Ezpeleta. The plants live at high altitude in páramo ecosystems. The trunk is thick, with succulent hairy leaves disposed in a dense spiral pattern. Marcescent leaves help protect the plants from cold. The flowers are usually yellow, similar to daisies. Some members of the genus exhibit a caulirosulate growth habit. The frailejón plant is endangered due to destruction of the páramo for agricultural purposes, especially potato crops. This activity continues, despite the Colombian government declaring it illegal. Since about 2010 the plants have also come under attack by beetle larvae, a moth and a fungus, some new to science but suspected to be related to climate change which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andes
The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S latitude), and has an average height of about . The Andes extend from north to south through seven South American countries: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile, and Argentina. Along their length, the Andes are split into several ranges, separated by intermediate depressions. The Andes are the location of several high plateaus—some of which host major cities such as Quito, Bogotá, Cali, Arequipa, Medellín, Bucaramanga, Sucre, Mérida, El Alto and La Paz. The Altiplano plateau is the world's second-highest after the Tibetan plateau. These ranges are in turn grouped into three major divisions based on climate: the Tropical Andes, the Dry Andes, and the Wet Andes. The Andes Mountains are the highest mountain ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moose
The moose (in North America) or elk (in Eurasia) (''Alces alces'') is a member of the New World deer subfamily and is the only species in the genus ''Alces''. It is the largest and heaviest extant species in the deer family. Most adult male moose have distinctive broad, palmate ("open-hand shaped") antlers; most other members of the deer family have antlers with a dendritic ("twig-like") configuration. Moose typically inhabit boreal forests and temperate broadleaf and mixed forests of the Northern Hemisphere in temperate to subarctic climates. Hunting and other human activities have caused a reduction in the size of the moose's range over time. It has been reintroduced to some of its former habitats. Currently, most moose occur in Canada, Alaska, New England (with Maine having the most of the lower 48 states), New York State, Fennoscandia, the Baltic states, Poland, Kazakhstan, and Russia. Its diet consists of both terrestrial and aquatic vegetation. Predators of moos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dypsis
''Dypsis'' is a genus of flowering plants in the family Arecaceae. They are slender, evergreen palms with yellow flowers carried in panicles amongst the pinnate leaves. Many ''Dypsis'' species have aerial branching (above the main trunk), a rare growth habit among palms. Some have marcescent leaves that remain attached after death and trap litter for nutrients. Etymology The etymology is obscure but may be related to the Greek ' ‘I dive’ or ' ‘diver’. The species are native to Tanzania, Madagascar, and various islands in the Indian Ocean (Mauritius Mauritius ( ; french: Maurice, link=no ; mfe, label=Mauritian Creole, Moris ), officially the Republic of Mauritius, is an island nation in the Indian Ocean about off the southeast coast of the African continent, east of Madagascar. It incl ... and Comoros). A few are naturalized in other regions, especially in the Caribbean. Selected species References Arecaceae genera Trees of Africa Taxonomy art ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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