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Gymnostoma
''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high elevations having temperate climates, in forests in the region of the western Pacific Ocean and Malesia. In New Caledonia, published botanical science describes eight species found growing naturally, which botanists have not found anywhere else (endemics). Other species are native to Borneo, Sumatra, Maluku, and New Guinea, and one endemic species each in Fiji and the Wet Tropics of Queensland, Australia. The genus was first scientifically described by Lawrie A. S. Johnson in 1980. Many of the ''Gymnostoma'' species combinations of names ( binomials) were described by him in 1982. , a global total of eighteen species have been found and described. The majority of the species grow in rainforests, in the habitats of open, sunny, long-term gaps, from river bank (riparian) si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casuarinaceae
The Casuarinaceae are a family of dicotyledonous flowering plants placed in the order Fagales, consisting of four genera and 91 species of trees and shrubs native to eastern Africa, Australia, Southeast Asia, Malesia, Papuasia, and the Pacific Islands. At one time, all species were placed in the genus '' Casuarina''. Lawrence Alexander Sidney Johnson separated out many of those species and renamed them into the new genera of '' Gymnostoma'' in 1980 and 1982, '' Allocasuarina'' in 1982, and ''Ceuthostoma'' in 1988, with some additional formal descriptions of new species in each other genus. At the time, it was somewhat controversial. The monophyly of these genera was later supported in a 2003 phylogenetic study of the family. In the Wettstein system, this family was the only one placed in the order Verticillatae. Likewise, in the Engler, Cronquist, and Kubitzki systems, the Casuarinaceae were the only family placed in the order Casuarinales. Members of this family are charac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Massif
A massif () is a principal mountain mass, such as a compact portion of a mountain range, containing one or more summits (e.g. France's Massif Central). In mountaineering literature, ''massif'' is frequently used to denote the main mass of an individual mountain. As a purely scientific term in geology, however, a "massif" is separately and more specifically defined as a section of a planet's crust (geology), crust that is demarcated by geologic fault, faults or lithospheric flexure, flexures. In the plate tectonics, movement of the crust, a massif tends to retain its internal structure while being displaced as a whole. A massif is a smaller structural unit than a tectonic plate and is considered the fourth-largest driving force in geomorphology. The word "massif" originates from French (in which the word also means "massive"), where it is used to refer to a large mountain mass or compact group of connected mountains forming an independent portion of a range. The Cydonia (regi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maquis Shrubland
220px, Low maquis in Corsica 220px, High ''macchia'' in Sardinia ( , , ) or ( , ; often in Italian; , ; ; ; ) is a savanna-like shrubland biome in the Mediterranean region, typically consisting of densely growing evergreen shrubs. Maquis is characterized by plants of the family Lamiaceae, genera '' Laurus'' and '' Myrtus'', and species '' Olea europaea'', '' Ceratonia siliqua'', and '' Ficus carica''. It is similar to garrigue Garrigue or garigue ( ), also known as phrygana ( , n. pl.), is a type of low scrubland ecoregion and plant community in the Mediterranean forests, woodlands, and scrub biome. It is found on limestone soils in southern France and around the .... See also * Mining maquis * Maquis (other) * Mediterranean forests, woodlands, and scrub References External links * * * {{DEFAULTSORT:Maquis Shrubland * Ecoregions of Europe Ecoregions of Metropolitan France Environment of the Mediterranean Mediterranean forests, woodlands, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serpentine Soil
Serpentine soil is an uncommon soil type produced by weathered ultramafic rock such as peridotite and its metamorphic derivatives such as serpentinite. More precisely, serpentine soil contains minerals of the serpentine subgroup, especially antigorite, lizardite, and chrysotile or white asbestos, all of which are commonly found in ultramafic rocks. The term "serpentine" is commonly used to refer to both the soil type and the mineral group which forms its parent materials. Serpentine soils exhibit distinct chemical and physical properties and are generally regarded as poor soils for agriculture. The soil is often reddish, brown, or gray in color due to its high iron and low organic content. Geologically, areas with serpentine bedrock are characteristically steep, rocky, and vulnerable to erosion, which causes many serpentine soils to be rather shallow. The shallow soils and sparse vegetation lead to elevated soil temperatures and dry conditions. Due to their ultramafic origin, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inceptisol
Inceptisols are a soil order in USDA soil taxonomy. They form quickly through alteration of parent material. They are more developed than Entisols. They have no accumulation of clays, iron oxide, aluminium oxide or organic matter. They have an ochric or umbric horizon and a cambic subsurface horizon. In the World Reference Base for Soil Resources (WRB), most Inceptisols are Cambisols or Umbrisols. Some may be Nitisols. Many Aquepts belong to Gleysols and Stagnosols. Suborders * Aquepts – with a water table close to the surface *Anthrepts In the USDA soil taxonomy, Anthrepts is a term for soil with evidence of human habitation and farming. See also *Anthrosols in the World Soil Classification. *Inceptisols of which anthrepts are a suborder of. References {{reflist Types of so ... – with a plaggen or anthropic epipedon, a sign of intense and prolonged human activity * Gelepts – in very cold climates * Cryepts – in cold climates * Udepts – in humid clima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultramafic
Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are usually composed of greater than 90% mafic minerals (dark colored, high magnesium and iron content). Earth's mantle is composed of ultramafic rocks. Ultrabasic is a more inclusive term that includes igneous rocks with low silica content that may not be extremely enriched in Fe and Mg, such as carbonatites and ultrapotassic igneous rocks. Intrusive ultramafic rocks Intrusive ultramafic rocks are often found in large, layered ultramafic intrusions where differentiated rock types often occur in layers. Such cumulate rock types do not represent the chemistry of the magma from which they crystallized. The ultramafic intrusives include the dunites, peridotites and pyroxenites. Other rare varieties include troctolite which has a greater pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base Saturation
Cation-exchange capacity (CEC) is a measure of how many cations can be retained on soil particle surfaces. Negative charges on the surfaces of soil particles bind positively-charged atoms or molecules (cations), but allow these to exchange with other positively charged particles in the surrounding soil water. This is one of the ways that solid materials in soil alter the chemistry of the soil. CEC affects many aspects of soil chemistry, and is used as a measure of soil fertility, as it indicates the capacity of the soil to retain several nutrients (e.g. K+, NH4+, Ca2+) in plant-available form. It also indicates the capacity to retain pollutant cations (e.g. Pb2+). Definition and principles Cation-exchange capacity is defined as the amount of positive charge that can be exchanged per mass of soil, usually measured in cmolc/kg. Some texts use the older, equivalent units me/100g or meq/100g. CEC is measured in moles of electric charge, so a cation-exchange capacity of 10 cmolc/kg co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laterite
Laterite is a soil type rich in iron and aluminium and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content. They develop by intensive and prolonged weathering of the underlying parent rock, usually when there are conditions of high temperatures and heavy rainfall with alternate wet and dry periods. The process of formation is called laterization. Tropical weathering is a prolonged process of chemical weathering which produces a wide variety in the thickness, grade, chemistry and ore mineralogy of the resulting soils. The majority of the land area containing laterites is between the tropics of Cancer and Capricorn. Laterite has commonly been referred to as a soil type as well as being a rock type. This, and further variation in the modes of conceptualizing about laterite (e.g. also as a complete weathering profile or theory about weathering), has led to calls for the term to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allotropes Of Iron
At atmospheric pressure, three allotropic forms of iron exist, depending on temperature: alpha iron (α-Fe, ferrite), gamma iron (γ-Fe, austenite), and delta iron (δ-Fe, similar to alpha iron). At very high pressure, a fourth form exists, epsilon iron (ε-Fe, hexaferrum). Some controversial experimental evidence suggests the existence of a fifth high-pressure form that is stable at very high pressures and temperatures. The phases of iron at atmospheric pressure are important because of the differences in solubility of carbon, forming different types of steel. The high-pressure phases of iron are important as models for the solid parts of planetary cores. The inner core of the Earth is generally assumed to consist essentially of a crystalline iron-nickel alloy with ε structure. The outer core surrounding the solid inner core is believed to be composed of liquid iron mixed with nickel and trace amounts of lighter elements. Standard pressure allotropes Alpha iron (α-Fe) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
