|
Ambrosia Deltoidea
''Ambrosia deltoidea'' is a North American species of flowering plant in the family Asteraceae known by the common names triangle bur ragweed, triangle bursage, and triangleleaf bursage. Distribution The plant is native to the Sonoran Desert region of North America, where it can be found in Baja California, Baja California Sur, and Sonora in Mexico, with its distribution extending north into Arizona in the United States.Marshall, K. Anna. 1994''Ambrosia deltoidea''.In: Fire Effects Information System, nline U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. This shrub grows in desert habitat, such as desert grasslands and shrublands. It is a dominant or codominant species, and one of the most abundant plants,Bowers, J. E. (2002)Regeneration of triangle-leaf bursage (''Ambrosia deltoidea'': Asteraceae): Germination behavior and persistent seed bank.''The Southwestern Naturalist'' 47(3) 449-53. in the Arizona Upland Su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torr
The torr (symbol: Torr) is a unit of pressure based on an absolute scale, defined as exactly of a standard atmosphere (). Thus one torr is exactly (≈ ). Historically, one torr was intended to be the same as one "millimeter of mercury", but subsequent redefinitions of the two units made them slightly different (by less than ). The torr is not part of the International System of Units (SI). It is often combined with the metric prefix milli to name one millitorr (mTorr) or 0.001 Torr. The unit was named after Evangelista Torricelli, an Italian physicist and mathematician who discovered the principle of the barometer in 1644. Nomenclature and common errors The unit name ''torr'' is written in lower case, while its symbol ("Torr") is always written with upper-case initial; including in combinations with prefixes and other unit symbols, as in "mTorr" (millitorr) or "Torr⋅L/s" (torr-litres per second). The symbol (uppercase) should be used with prefix symbols (thus, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercidium
''Parkinsonia'' , also ''Cercidium'' , is a genus of flowering plants in the pea family, Fabaceae. It contains about 12 species that are native to semi-desert regions of Africa and the Americas. The name of the genus honors English apothecary and botanist John Parkinson (1567–1650). They are large shrubs or small trees growing to tall, dry season deciduous, with sparse, open, thorny crowns and green bark. The leaves are pinnate, sometimes bipinnate, with numerous small leaflets; they are only borne for a relatively short time after rains, with much of the photosynthesis carried out by the green twigs and branches. The flowers are symmetrical or nearly so, with five yellow or white petals. The fruit is a pod containing several seeds. Most American species are known by the common name of palo verde or paloverde, from the Spanish words meaning "green pole" or "green stick". This name is derived from its characteristic green trunk. The palo verde (not species-specific) is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gynoecium
Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' and is typically surrounded by the pollen-producing reproductive organs, the stamens, collectively called the androecium. The gynoecium is often referred to as the "female" portion of the flower, although rather than directly producing female gametes (i.e. egg cells), the gynoecium produces megaspores, each of which develops into a female gametophyte which then produces egg cells. The term gynoecium is also used by botanists to refer to a cluster of archegonia and any associated modified leaves or stems present on a gametophyte shoot in mosses, liverworts, and hornworts. The corresponding terms for the male parts of those plants are clusters of antheridia within the androecium. Flowers that bear a gynoecium but no stamens are called ''pi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Head (botany)
A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, composite flowers, or capitula, which are special types of inflorescences in which anything from a small cluster to hundreds or sometimes thousands of flowers are grouped together to form a single flower-like structure. Pseudanthia take various forms. The real flowers (the florets) are generally small and often greatly reduced, but the pseudanthium itself can sometimes be quite large (as in the heads of some varieties of sunflower). Pseudanthia are characteristic of the daisy and sunflower family (Asteraceae), whose flowers are differentiated into ray flowers and disk flowers, unique to this family. The disk flowers in the center of the pseudanthium are actinomorphic and the corolla is fused into a tube. Flowers on the periphery are zygomorp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stamen
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament and an anther which contains ''sporangium, microsporangia''. Most commonly anthers are two-lobed and are attached to the filament either at the base or in the middle area of the anther. The sterile tissue between the lobes is called the connective, an extension of the filament containing conducting strands. It can be seen as an extension on the dorsal side of the anther. A pollen grain develops from a microspore in the microsporangium and contains the male gametophyte. The stamens in a flower are collectively called the androecium. The androecium can consist of as few as one-half stamen (i.e. a single locule) as in ''Canna (plant), Canna'' species or as many as 3,482 stamens which have been counted in the saguaro (''Carnegiea gigantea'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed on the axis of a plant. The modifications can involve the length and the nature of the internodes and the phyllotaxis, as well as variations in the proportions, compressions, swellings, adnations, connations and reduction of main and secondary axes. One can also define an inflorescence as the reproductive portion of a plant that bears a cluster of flowers in a specific pattern. The stem holding the whole inflorescence is called a peduncle. The major axis (incorrectly referred to as the main stem) above the peduncle bearing the flowers or secondary branches is called the rachis. The stalk of each flower in the inflorescence is called a pedicel. A flower that is not part of an inflorescence is called a solitary flower and its stalk is al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adventitious Root
Important structures in plant development are buds, shoots, roots, leaves, and flowers; plants produce these tissues and structures throughout their life from meristems located at the tips of organs, or between mature tissues. Thus, a living plant always has embryonic tissues. By contrast, an animal embryo will very early produce all of the body parts that it will ever have in its life. When the animal is born (or hatches from its egg), it has all its body parts and from that point will only grow larger and more mature. However, both plants and animals pass through a phylotypic stage that evolved independently and that causes a developmental constraint limiting morphological diversification. According to plant physiologist A. Carl Leopold, the properties of organization seen in a plant are emergent properties which are more than the sum of the individual parts. "The assembly of these tissues and functions into an integrated multicellular organism yields not only the characteristic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taproot
A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproot is a storage organ so well developed that it has been cultivated as a vegetable. The taproot system contrasts with the adventitious or fibrous root system of plants with many branched roots, but many plants that grow a taproot during germination go on to develop branching root structures, although some that rely on the main root for storage may retain the dominant taproot for centuries, for example ''Welwitschia''.Taproot also store nutrition. Plants with taproots are often vegetables. Description Dicots, one of the two divisions of flowering plants (angiosperms), start with a taproot, which is one main root forming from the enlarging radicle of the seed. The tap root can be persistent throughout the life of the plant but is most oft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shrub
A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple stems and shorter height, less than tall. Small shrubs, less than 2 m (6.6 ft) tall are sometimes termed as subshrubs. Many botanical groups have species that are shrubs, and others that are trees and herbaceous plants instead. Some definitions state that a shrub is less than and a tree is over 6 m. Others use as the cut-off point for classification. Many species of tree may not reach this mature height because of hostile less than ideal growing conditions, and resemble a shrub-sized plant. However, such species have the potential to grow taller under the ideal growing conditions for that plant. In terms of longevity, most shrubs fit in a class between perennials and trees; some may only last about five y ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overgrazing
Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature reserves. It can also be caused by immobile, travel restricted populations of native or non-native wild animals. Overgrazing reduces the usefulness, productivity, and biodiversity of the land and is one cause of desertification and erosion. Overgrazing is also seen as a cause of the spread of invasive species of non-native plants and of weeds. Degrading land, emissions from animal agriculture and reducing the biomass in a ecosystem contribute directly to climate change. Overgrazing can be reversed or prevented by removing grazers in order to give plants time to recover between grazing events. Successful planned grazing strategies have been support in the American bison of the Great Plains, or migratory Wildebeests of the African savann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opuntia
''Opuntia'', commonly called prickly pear or pear cactus, is a genus of flowering plants in the cactus family Cactaceae. Prickly pears are also known as ''tuna'' (fruit), ''sabra'', ''nopal'' (paddle, plural ''nopales'') from the Nahuatl word for the pads, or nostle, from the Nahuatl word for the fruit; or paddle cactus. The genus is named for the Ancient Greek city of Opus, where, according to Theophrastus, an edible plant grew and could be propagated by rooting its leaves. The most common culinary species is the Indian fig opuntia (''O. ficus-indica''). Description ''O. ficus-indica'' is a large, trunk-forming, segmented cactus that may grow to with a crown of over in diameter and a trunk diameter of . Cladodes (large pads) are green to blue-green, bearing few spines up to or may be spineless. Prickly pears typically grow with flat, rounded cladodes (also called platyclades) containing large, smooth, fixed spines and small, hairlike prickles called glochids that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jatropha
''Jatropha'' is a genus of flowering plants in the spurge family, Euphorbiaceae. The name is derived from the Greek words ἰατρός (''iatros''), meaning "physician", and τροφή (''trophe''), meaning "nutrition", hence the common name physic nut. Another common name is nettlespurge. It contains approximately 170 species of succulent plants, shrubs and trees (some are deciduous, like ''Jatropha curcas''). Most of these are native to the Americas, with 66 species found in the Old World. Plants produce separate male and female flowers. As with many members of the family Euphorbiaceae, ''Jatropha'' contains compounds that are highly toxic. ''Jatropha'' species have traditionally been used in basketmaking, tanning and dye production. In the 2000s, one species, ''Jatropha curcas'', generated interest as an oil crop for biodiesel production and also medicinal importance when used as lamp oil; native Mexicans in the Veracruz area developed by selective breeding a ''Jatropha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
