Chromolaena odorata

Chromolaena odorata
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Genus: Chromolaena
Species: C. odorata
Binomial name
Chromolaena odorata
(L.) King & H.E. Robins.
Synonyms[1]
Flower in Kerala
Indian Cabbage White (Pieris canidia) on C. odorata at Samsing in Darjeeling district of West Bengal, India.

Chromolaena odorata is a tropical and subtropical species of flowering shrub in the sunflower family. It is native to North America, from Florida and Texas to Mexico and the Caribbean,[2] and has been introduced to South America, tropical Asia, west Africa, and parts of Australia.[3][4][5] Common names include Siam weed, Christmas bush, devil weed, camfhur grass, common floss flower and triffid.[6]

Description

Chromolaena odorata is a rapidly growing perennial herb. It is a multi-stemmed shrub to 2.5 m (100 inches) tall in open areas. It has soft stems but the base of the shrub is woody. In shady areas it becomes etiolated and behaves as a creeper, growing on other vegetation. It can then become up to 10 m (33 feet) tall. The plant is hairy and glandular and the leaves give off a pungent, aromatic odour when crushed. The leaves are opposite, triangular to elliptical with serrated edges. Leaves are 4–10 cm long by 1–5 cm wide (up to 4 x 2 inches). Leaf petioles are 1–4 cm long. The white to pale pink tubular flowers are in panicles of 10 to 35 flowers that form at the ends of branches. The seeds are achenes and are somewhat hairy. They are mostly spread by the wind, but can also cling to fur, clothes and machinery, enabling long distance dispersal. Seed production is about 80000 to 90000 per plant. Seeds need light to germinate. The plant can regenerate from the roots. In favorable conditions the plant can grow more than 3 cm per day.[7]

Classification

It was earlier taxonomically classified under the genus Eupatorium, but is now considered more closely related to other genera in the tribe Eupatorieae.[8]

Uses

It is sometimes grown as a medicinal and ornamental plant. It is used as a traditional medicine in Indonesia, Thailand, Malaysia and parts of Africa including Nigeria. The young leaves are crushed, and the resulting liquid can be used to treat skin wounds. In traditional medicine of Thailand the plant is used for the treatment of wounds, rashes, diabetes, and as insect repellent. It has antifungal and antibacterial property.

The phytoprostane compound chromomoric acid C-I has been identified from Chromolaena odorata as a strong inducer of the activity of the transcription factor NFE2L2 (Nrf2), a master regulator of a range of genes with defensive, anti-inflammatory, and detoxifying functions.[9] A recent review indicates that the ethno-pharmacological, funcigicidal, nematicidal importance of the plant and its use as a fallow species and as a soil fertility improvement plant in the slash and burn rotation system of agriculture has contributed to its continued use and spread in Nigeria.[10]

Invasive species

A sign in Kloof encouraging the elimination of Chromolaena odorata, colloquially known as Triffids

Chromolaena odorata is considered an invasive weed of field crops and natural environments in its introduced range.[11] It has been reported to be the most problematic invasive species within protected rainforests in Africa.[12] In Western Africa it prevents regeneration of tree species in areas of shifting cultivation. It affects species diversity in southern Africa. The plant's flammability affects forest edges.[13] In Sri Lanka it is a major weed in disturbed areas and coconut plantations.[6]

Control

Biological control with a defoliating artiid was attempted in the 1970s.[14]

In the Ashanti region of Ghana Pareuchaetes pseudoinsulata was introduced to some effect in a pilot study in the Ashanti region.[15]

A renewed call for coordinated biological control effort in Nigeria was made in 2014, to attempt to bring the plant back into an ecological equilibrium.[10]

In Australia a systematic eradication programme with herbicide has been initiated.[16]

History of introduction

In the nineteenth century Chromolaena odorata escaped from the botanical gardens at Dacca (India), Java (Indonesia) and Peradeniya (Sri Lanka). In Western Africa the plant was accidentally introduced with forestry seeds. It was introduced as an ornamental in Southern Africa, and was introduced to Ivory Coast in 1952 to control Imperata grasses. It was first found in Queensland, Australia in 1994 and was perhaps introduced with foreign pasture seeds.[17]

Toxicity

Chromolaena odorata contains carcinogenic pyrrolizidine alkaloids.[18] It is toxic to cattle.[6] It can also cause allergic reactions.[19]

See also

References

  1. ↑ The Plant List, Chromolaena odorata (L.) R.M.King & H.Rob.
  2. ↑ "Chromolaena odorata". Flora of North America.
  3. ↑ Flora of China, 飞机草 fei ji cao Chromolaena odorata (Linnaeus) R. M. King & H. Robinson
  4. ↑ Tropicos, Chromolaena odorata (L.) R.M. King & H. Rob.
  5. ↑ Atlas of Living Australia
  6. 1 2 3 Lalith Gunasekera, Invasive Plants: A guide to the identification of the most invasive plants of Sri Lanka, Colombo 2009, p. 116–117.
  7. ↑ Lalith Gunasekera, Invasive Plants: A guide to the identification of the most invasive plants of Sri Lanka, Colombo 2009, p. 116–117. ”Siam weed or chromolaena (Chromolaena odorata)” Weed Management Guide at http://www.environment.gov.au/biodiversity/invasive/weeds/publications/guidelines/alert/pubs/c-odorata.pdf and Pierre Binggeli ”Chromolaena odorata (L.) King & Robinson (Asteraceae)”, 1997, at http://pages.bangor.ac.uk/~afs101/iwpt/web-sp4.htm
  8. ↑ GJ Schmidt, EE Schilling (May 2000). "Phylogeny and Biogeography of Eupatorium (Asteraceae: Eupatorieae) Based on Nuclear ITS Sequence". American Journal of Botany (Botanical Society of America) 87 (5): 716–726. doi:10.2307/2656858. JSTOR 2656858. PMID 10811796.
  9. ↑ Heiss EH, Tran TV, Zimmermann K, Schwaiger S, Vouk C, Mayerhofer B, Malainer C, Atanasov AG, Stuppner H, Dirsch VM. Identification of Chromomoric Acid C-I as an Nrf2 Activator in Chromolaena odorata. J Nat Prod. 2014 Jan 29. PubMed PMID 24476568.
  10. 1 2 Uyi OO, Ekhator F, Ikuenobe CE, Borokini TI, Aigbokhan EI, Egbon IN, Adebayo AR, Igbinosa IB, Okeke CO, Igbinosa EO, Omokhua GA. 2014. Chromolaena odorata invasion in Nigeria: A case for coordinated biological control Management of Biological Invasions (2014) 5(4): 377–393.
  11. ↑ "Siam weed or chromolaena (Chromolaena odorata)" Weed Management Guide at http://www.environment.gov.au/biodiversity/invasive/weeds/publications/guidelines/alert/pubs/c-odorata.pdf and Pierre Binggeli ”Chromolaena odorata (L.) King & Robinson (Asteraceae)”, 1997, at http://pages.bangor.ac.uk/~afs101/iwpt/web-sp4.htm
  12. ↑ TT Struhsaker, PJ Struhsaker, KS Siex (May 2005). "Conserving Africa’s rain forests: problems in protected areas and possible solutions" (PDF). Biological Conservation 123 (1): 45–54. doi:10.1016/j.biocon.2004.10.007. ISSN 0006-3207.
  13. ↑ Pierre Binggeli ”Chromolaena odorata (L.) King & Robinson (Asteraceae)”, 1997, at http://pages.bangor.ac.uk/~afs101/iwpt/web-sp4.htm
  14. ↑ Gunasekera, L. (2009). Invasive Plants: A guide to the identification of the most invasive plants in Sri Lanka. Colombo. 116-117
  15. ↑ http://www.ehs.cdu.edu.au/chromolaena/proceedings/fourth/tim.htm
  16. ↑ Pierre Binggeli ”Chromolaena odorata (L.) King & Robinson (Asteraceae)”, 1997, at http://pages.bangor.ac.uk/~afs101/iwpt/web-sp4.htm ”Siam weed or chromolaena (Chromolaena odorata)” Weed Management Guide at http://www.environment.gov.au/biodiversity/invasive/weeds/publications/guidelines/alert/pubs/c-odorata.pdf
  17. ↑ Pierre Binggeli ”Chromolaena odorata (L.) King & Robinson (Asteraceae)”, 1997, at http://pages.bangor.ac.uk/~afs101/iwpt/web-sp4.htm
  18. ↑ Fu, P.P., Yang, Y.C., Xia, Q., Chou, M.C., Cui, Y.Y., Lin G., "Pyrrolizidine alkaloids-tumorigenic components in Chinese herbal medicines and dietary supplements", Journal of Food and Drug Analysis, Vol. 10, No. 4, 2002, pp. 198-211
  19. ↑ ”Siam weed or chromolaena (Chromolaena odorata)” Weed Management Guide at http://www.environment.gov.au/biodiversity/invasive/weeds/publications/guidelines/alert/pubs/c-odorata.pdf

Further reading

External links

Media related to Chromolaena odorata at Wikimedia Commons Data related to Chromolaena odorata at Wikispecies

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