Misplaced Pages

Weed: Difference between revisions

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
Browse history interactively← Previous editNext edit →Content deleted Content addedVisualWikitext
Revision as of 02:06, 27 April 2010 view sourceBeeblebrox (talk | contribs)Autopatrolled, Administrators112,458 editsm Reverted 1 edit by 76.70.125.97 identified as vandalism to last revision by Beeblebrox. (TW)← Previous edit Revision as of 03:08, 27 April 2010 view source 70.149.101.74 (talk)No edit summaryTag: blankingNext edit →
Line 1: Line 1:
how jesus came up with religion
{{pp-vandalism|small=yes}}
weed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is good
{{pp-move-indef}}
{{About|plants specifically called weeds}}
{{See also|Invasive species}}
{{TOCright}}

] is a common weed all over the world, especially in Europe, Asia and the Americas.]]
A '''weed''' in a general sense is a ] that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-made settings such as ]s, ]s or ] areas, but also in parks, woods and other natural areas. More specifically, the term is often used to describe ] or nonnative plants that grow and reproduce aggressively.<ref>{{cite book | isbn = 0-7167-1031-5 | last = Janick | first = Jules | title = Horticultural Science | location = San Francisco | publisher = W.H. Freeman | year = 1979 | page = 308 | edition = 3rd}}</ref> Generally, a weed is a plant in an undesired place.

Weeds may be unwanted for a number of reasons: they might be unsightly, or crowd out or restrict light to more desirable plants or use limited ]s from the ]. They can harbor and spread plant ]s that infect and degrade the quality of ] or ] plants. Some weeds are a nuisance because they have thorns or prickles, some have chemicals that cause skin irritation or are hazardous if eaten, or have parts that come off and attach to fur or clothes.

The term ''weed'' in its general sense is a subjective one, without any classification value, since a "weed" is not a weed when growing where it belongs or is wanted. Indeed, a number of "weeds" have been used in gardens or other cultivated-plant settings. An example is the ], '']'', which was a common field weed exported from ] along with ], but now sometimes grown as a garden plant.<ref>{{cite web | url = http://davesgarden.com/pf/go/1341/ | work = PlantFiles | title = Detailed information on Corn Cockle (Agrostemma githago) | accessdate = February 15, 2009}}</ref>

Professor ] of ] defines weeds as plants that create environmental conditions in which it cannot reproduce. He takes the example of pine trees that crowd out sunlight such that its own offspring cannot grow. Weeds continue to exist, because the environment is continually being disturbed to create open conditions for new generations, such as forest fires and human activity.<ref>A speech given on the radio program ''Big Ideas'', (5/11/2003): "A weed is literally a plant... which comes into a disturbed habitat, which then changes the nature of the soil, the shading, and everything, and the moisture, ectcetera, in such a way that it cannot reproduce itself in that habitat."</ref>

==Distribution==
], a ] native to southern Europe and the Middle East that is an invasive weed in parts of ].]]
Weedy plants generally share similar ]s that give them advantages and allow them to proliferate in disturbed environments whose soil or natural vegetative cover has been damaged. Naturally occurring disturbed environments include ]s and other windswept areas with shifting soils, ] flood plains, ]s and ]s, and areas that are often burned. Since human agricultural practices often mimic these natural environments where weedy species have evolved, weeds have adapted to grow and proliferate in human-disturbed areas such as agricultural fields, lawns, roadsides, and construction sites. The weedy nature of these species often gives them an advantage over more desirable crop species because they often grow quickly and ] quickly, have seeds that persist in the ] for many years, or have short lifespans with multiple generations in the same growing season. Perennial weeds often have underground stems that spread out under the soil surface or, like ground ivy ('']''), have creeping stems that root and spread out over the ground.<ref>{{cite web | url = http://employees.csbsju.edu/ssaupe/biol327/Lecture/Plant_Foraging_case_study.pdf | title = Plant Foraging: Two Case Studies | first = Stephen G. | last = Saupe | accessdate = February 15, 2009}}</ref>

Some plants become dominant when introduced into new environments because they are freed from specialist consumers; in what is sometimes called the “natural enemies hypothesis,” plants freed from these specialist consumers may increase their competitive ability. In locations were predation and mutual competitive relationships no longer exist, some plants are able to increase allocation of resources into growth or reproduction. The weediness of some species that are introduced into new environments can be caused by the introduction of new chemicals; sometimes called the "novel weapons hypothesis," these introduced ]ic chemicals, which indigenous plants are not yet adapted to, may limit the growth of established plants or the germination and growth of seeds and seedlings.<ref name=Willis2007>{{Cite book| title = The History of Allelopathy| url = http://www.google.com/books?id=C-nPBYjDAjYC&pg=PA3&| year = 2007| author = Willis, Rick J.| journal = Springer| page = 8| isbn = 140204092X| accessdate = 2009-08-17}}</ref><ref>{{cite web|url=http://plantecology.dbs.umt.edu/Full%20text%20papers%20and%20abstracts/2004%20papers/Callaway&Ridenour2004NOVEL.pdf |title=Callaway.qxd |format=PDF |date= |accessdate=2010-03-20}}</ref>

== Relation to humans ==
As long as humans have cultivated plants, weeds have been a problem. Weeds have even been mentioned in religious and literature texts like the following quotes from ] and a ] ]:

<blockquote>"Cursed is the ground because of you; through painful toil you will eat of it all the days of your life. It will produce thorns and thistles for you, and you will eat the plants of the field. By the sweat of your brow you will eat your food until you return to the ground,"<ref>Genesis 3:17-19 New International Version</ref></blockquote>

<blockquote>"To thy fair flower add the rank smell of weeds: But why thy odour matcheth not thy show, The soil is this, that thou dost common grow."<ref>{{cite book | authorlink = William Shakespeare | first = William | last = Shakespeare | url = http://www.infoplease.com/t/lit/shakespeare-sonnets/69.html | title = Those parts of thee that the world's eye doth view | publisher = ] | accessdate = February 15, 2009}}</ref></blockquote>

]

Weed seeds are often collected and transported with crops after the harvesting of ]s. Many weed species have moved out of their natural geographic locations and have spread around the world with humans. (See ].) Not all weeds have the same ability to damage crops and horticultural plants or cause harm to animals. Some have been classified as ]s by governmental authorities because if left unchecked, they often dominate the environment where crop plants are to be grown or cause harm to ]. They are often foreign species mistakenly or accidentally imported into a region where there are few natural controls to limit their population and spread. Many weeds have ideal locations for growth and reproduction because of the large areas of open soil created by the conversion of land to field agriculture. Farming practices that produce unvegetated soils part of the year and human distribution of food crops mixed with seeds of weeds from other parts of the world have facilitated the colonization of vast new areas for many weedy species; humans are the vector of transport and the producer of disturbed environments, thus many weedy species have an ideal association with humans.

A number of weeds, such as the ] '']'', are edible, and their leaves and roots may be used for ] or ]. ] is common weed over much of the world, and is sometimes used to make ] and other medicine in ]. These so-called "]s" may have other beneficial effects, such as drawing away the attacks of crop-destroying ]s, but often are breeding grounds for insects and pathogens that attack other plants. Dandelions are one of several species which break up ] in overly cultivated fields, helping crops grow deeper root systems. Some modern species of domesticated ] actually originated as weeds in cultivated fields and have been bred by people into garden plants for their flowers or foliage.

==Examples==
*'']''
*] - perennial, spreading by runners, rhizomes and seeds.
*]
*] – perennial, spreads by seeds that persist in the soil for many years
*] – biennial
*] - annual, biennial, or perennial<ref>On lawns and elsewhere, some people consider clover a weed, and some do not, as it has some beneficial effects.</ref>
*] – perennial, fast-spreading plants with long creeping stems
*] – perennial, wind-spread, fast-growing, and drought-tolerant
*] – perennial
*]
*] – perennial
*] – perennial, with underground stems
*]<ref>{{cite web | url = http://plants.usda.gov/java/profile?symbol=CASA3 | title = PLANTS Profile for Cannabis sativa (marijuana) | publisher = ] | work = ] | accessdate = February 15, 2009}}</ref><ref name=By1997>{{Cite book | editor-first = Mary Lynn | editor-last = Mathre | year = 1997 | title = Cannabis in medical practice: a legal, historical and pharmacological overview of the therapeutic use of Marijuana | page = 208 | url = http://books.google.com/books?id=1AWGDhIOvk0C&pg=PA208&dq=Cannabis+is+a++weedy+species&lr=&ei=lvI9SdTZEJ-qyATrzfTcCw&client=firefox-a | isbn = 9780786403615 | publisher = McFarland | location = Jefferson, NC | accessdate = February 15, 2009}}</ref>
*] – annual or biennial
*] – perennial
*] – annual
*] – annual
*] - perennial
*] – woody perennial
*] – biennial
*] – perennial
The five plants designated "injurious weeds" under UK law are:<ref>{{cite web | url = http://www.defra.gov.uk/rds/weeds-act.htm | DEFRA UK, | title = Weeds Act 1959 | archiveurl = http://web.archive.org/web/20070926235042/http://www.defra.gov.uk/rds/weeds-act.htm | archivedate = 2007-09-26 | publisher = ] (Defra), UK | accessdate = February 15, 2009}}</ref>
* ]
* ]
* ]
* ]
* ]

==See also==
<div style="column-count:2;-moz-column-count:2;-webkit-column-count:2">
*]
*]
*]
*]
*]
*]
*]
*]
*]
*]
</div>

==References==
{{reflist|2}}

==External links==
{{commonscat|Weeds (plants)}}
*
*

]
]
]

]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]

Revision as of 03:08, 27 April 2010

how jesus came up with religion 

weed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is goodweed is good