''Chromolaena odorata'' is a tropical and subtropical species of

flowering A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

shrub in the family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

. It is native to the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

, from

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

and

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

in the United States south through Mexico and the Caribbean to South America. It has been introduced to tropical Asia, West Africa, and parts of Australia. Common names include Siam weed, Christmas bush, jack in the box, devil weed, Communist Pacha (കമ്മ്യൂണിസ്റ്റ് പച്ച) in

Malayalam Malayalam (; , ) is a Dravidian languages, Dravidian language spoken in the Indian state of Kerala and the union territories of Lakshadweep and Puducherry (union territory), Puducherry (Mahé district) by the Malayali people. It is one of 2 ...

, common floss flower, rompe saragüey (in

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...

), Abani di egwu or Nsiibilibe (

Igbo language Igbo ( , ; Igbo: ''Ásụ̀sụ́ Ìgbò'' ) is the principal native language cluster of the Igbo people, a meta-ethnicity from Southeastern Nigeria. The number of Igboid languages depends on how one classifies a language versus a dialect, so ...

), ewé Akíntọ́lá ( Yorùbá) and

triffid The triffid is a fictional tall, mobile, carnivorous plant species, created by John Wyndham in his 1951 novel ''The Day of the Triffids'', which has since been adapted for film and television. The word "triffid" has become a common reference ...

.Lalith Gunasekera, ''Invasive Plants: A guide to the identification of the most invasive plants of Sri Lanka'', Colombo 2009, p. 116–117.

Description

''Chromolaena odorata'' is a rapidly growing perennial herb. It is a multi-stemmed shrub which grows up 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 In animals, a gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). Structure De ...

and the leaves give off a pungent, aromatic odour when crushed. The leaves are opposite, triangular to elliptical with

serrated Serration is a saw-like appearance or a row of sharp or tooth-like projections. A serrated cutting edge has many small points of contact with the material being cut. By having less contact area than a smooth blade or other edge, the applied p ...

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 A panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a panicle are o ...

of 10 to 35 flowers that form at the ends of branches. The seeds are

achenes An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not op ...

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 80,000 to 90,000 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.

Classification

It was earlier taxonomically classified under the genus ''

Eupatorium ''Eupatorium'' is a genus of flowering plants in the family Asteraceae, containing from 36 to 60 species depending on the classification system. Most are herbaceous perennials growing to tall. A few are shrubs. The genus is native to temperat ...

'', but is now considered more closely related to other genera in the tribe

Eupatorieae Eupatorieae is a tribe of over 2000D.J.N.Hind & H.E.Robinson. 2007. Tribe Eupatorieae In: ''The Families and Genera of Vascular Plants'' vol.VIII. (Joachim W.Kadereit & Charles Jeffrey, volume editors. Klaus Kubitzky, general editor). Springer-Ve ...

Uses

Chromolaena odorata seeds vijayan rajapuram

A recent review indicates that the ethno-pharmacological, fungicidal, 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.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

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Invasive species

''Chromolaena odorata'' is considered an invasive species, invasive weed of field crops and natural environments in its introduced range. It has been reported to be the most problematic invasive species within protected rainforests in

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

. 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. In Sri Lanka it is a major weed in disturbed areas and coconut plantations.

Control

Biological control with a defoliating Arctiid moth was attempted in the 1970s. A pilot study in the Ashanti region of Ghana introduced the moth '' Pareuchaetes pseudoinsulata'' to some effect. 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. In Australia a systematic eradication programme with herbicide has been initiated. The gall forming tephritid fly '' Cecidochares connexa'' was introduced into Guam from Indonesia in 1998 and is widespread across the island. Chromolaena odorata forms galls around the fly larvae that become a nutrient sink that diverts energy away from plant growth to provide nutritive tissue along the walls of the larval chamber. Between 1 and 7 larvae can be found in each gall.

History of introduction

In the nineteenth century ''Chromolaena odorata'' escaped from the botanical gardens at

Dacca Dhaka ( or ; bn, ঢাকা, Ḍhākā, ), formerly known as Dacca, is the capital and largest city of Bangladesh, as well as the world's largest Bengali-speaking city. It is the eighth largest and sixth most densely populated city ...

(India), Java (Indonesia) and

Peradeniya Peradeniya ( si, පේරාදෙණිය, translit=Pēradeniya; ta, பேராதனை, translit=Pērātaṉai) is a suburb of the city of Kandy Kandy ( si, මහනුවර ''Mahanuwara'', ; ta, கண்டி Kandy, ) is a m ...

(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 ''Imperata'' is a small but widespread genus of tropical and subtropical grasses, commonly known as satintails. Satintail grass species are perennial rhizomatous herbs with solid, erect stems and silky inflorescences. The best known species is ...

grasses. It was first found in Queensland, Australia in 1994 and was perhaps introduced with foreign pasture seeds. It is locally called ''Communist Pacha'' in the southern Indian state of

Kerala Kerala ( ; ) is a state on the Malabar Coast of India. It was formed on 1 November 1956, following the passage of the States Reorganisation Act, by combining Malayalam-speaking regions of the erstwhile regions of Cochin, Malabar, South ...

as the plant was introduced there in the 1950s, the era when the

communists Communism (from Latin la, communis, lit=common, universal, label=none) is a far-left sociopolitical, philosophical, and economic ideology and current within the socialist movement whose goal is the establishment of a communist society, a s ...

formed a government. Chromolaena odorata, also known as “devil weed,” was found on the east side of the Big Island (Hawai'i) earlier in 2021, the Hawaii Tribune-Herald reported on September 28, 2021.

Toxicity

''Chromolaena odorata'' contains

carcinogenic A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive subs ...

pyrrolizidine alkaloids.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. 198-21

It is toxic to cattle. It can also cause allergic reactions. Recent research has shown the plant is larvicidal against all major mosquito vectors.

References

External links

* *
Queensland Government Factsheet
* {{Taxonbar, from=Q2583146 odorata Medicinal plants of Central America Flora of the Caribbean Flora of Texas Flora of Florida Flora of Mexico Flora of South America Plants described in 1759 Invasive plant species in Sri Lanka Medicinal plants of North America Flora without expected TNC conservation status