Ageratina adenophora

Taxobox
name = "Ageratina adenophora"


regnum = Plantae
divisio = Magnoliophyta
classis = Magnoliopsida
ordo = Asterales
familia = Asteraceae
tribus = Eupatorieae
genus = "Ageratina"
species = "A. adenophora"
binomial = "Ageratina adenophora"
binomial_authority = (Spreng.) King & H.Rob.
synonyms ="Eupatorium adenophorum"
"Eupatorium glandulosum"

"Ageratina adenophora" (syn. "Eupatorium adenophorum") is a species of flowering plant in the daisy family known by many common names, including eupatory, sticky snakeroot, crofton weed, and Mexican devil.

Description

"Ageratina adenophora" is a perennial herbaceous shrub which may grow to 1 or 2 m (3–7 ft) high. It has opposite trowel-shaped serrated leaves that are 6–10 cm (2.4–4 in) long by 3–6 cm (1.4–2.4 in) in width. The small compound flowers occur in late spring and summer, and are found in clusters at the end of branches. Each flowerhead is up to 0.5 cm in diameter and creamy white in colour. They are followed by a small brown seed with a white feathery 'parachute'.

Distribution and habitat

It is native to Mexico, but it is known in many other parts of the world as an introduced species and often a noxious weed. It has caused great economic loss in agriculture in southwestern China, and is threatening the native biodiversity there. It was first inadvertently introduced to Yunnan around 1940, and its rapid spread is due in part to its allelopathic competition with other plant species.Baruah, N. C.; Sarma, J. C.; Sarma, S.; Sharma, R. P. Seed germination and growth inhibitory cadinenes from "Eupatorium adenophorum" Spreng. "J. Chem. Ecol." 1994, 20, 1885–1892.] It also a weed in Australia, where it was introduced to Sydney in 1904. It has spread along the coastline of New South Wales and southern Queensland.cite book |title=Winning the war of Weeds: The Essential Gardener's Guide to Weed Identification and Control |last=Wolff |first=Mark A. |year=1999 |publisher=Kangaroo Press |location=Kenthurst, NSW |isbn=0-86417-993-6|pages=p. 17] It is rated a "Class 4 Noxious Weed" under the NSW Noxious Weeds Act of 1993.

"Ageratina adenophora" has also spread in Hawaii and the mainland USA, where it is recognised as a weed in ten states of the South and Southwest.cite web |url=http://plants.usda.gov/java/profile?symbol=AGAD2 |title=Plants Profile &mndash; "Ageratina adenophora" (Spreng.) King & H. Rob. sticky snakeroot |accessdate=2008-09-20 |work=USDA website|publisher=U. S> Government, Department of Agriculture |date=2008]

Elsewhere it is an invasive species in many tropical and subtropical countries, including northeastern India, Sri Lanka, Nigeria, Southeast Asia, the Pacific Islands, the Canary Islands, and South Africa.

The plant can spread vegetatively, that is the stems can sprout roots and grow upon contact with earth. The seed is also carried by the wind or water and colonises disturbed areas, such as fields and areas near human habitation, readily. Seed may also be transported on animals and in soil.

Biochemistry

The plant contains many types of terpenes, alkaloids, and phenols such as flavonoids, phenylpropanoids, and coumarins. Cadinene sesquiterpenes play a role in the plant's allelopathy. [Yang, G. Q.; Wan, F. H.; Liu, W. X.; Zhang, X. W. Physiological effects of allelochemicals from leachates of "Ageratina adenophora" Spreng. on rice seedlings. "Allelopathy J." 2006, 18, 237–246.]

It is also poisonous to horses; in as little as eight weeks of consuming it, they may develop respiratory symptoms of breathlessness, known as "blowing disease", from the blowing horses may exhibit,cite web |url=http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=2&surveynumber=182 |title="Ageratina adenophora" |accessdate=2008-09-20 |work=University of California website |publisher=University of California] and may collapse from respiratory failure. Even in non-fatal cases, lung damage may be irreversible. [cite web |url= http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0010/155962/crofton-weed.pdf |title=Agfacts — Crofton Weed |accessdate=2008-09-20 |work=NSW Agriculture |publisher=NSW Government, department of Agriculture|year=2003|author=Trounce, Bob]

References

reflist

External links

* [http://plants.usda.gov/java/profile?symbol=AGAD2 USDA Plants Profile]
* [http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?316409 GRIN Species Profile]
* [http://calphotos.berkeley.edu/cgi/img_query?query_src=photos_index&where-taxon=Ageratina+adenophora Photo gallery]