''Eupatorium macrocephalum'' Less. aka pompom weed, is a cosmopolitan perennial plant belonging to the family of

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

and regarded as an invasive weed in some countries. It is native to the southern

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

and was introduced to

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

. It is classed as a principal weed in

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. In South Africa it has been cultivated as an ornamental, is often found on roadsides, and has become of concern for its invading of undisturbed climax grassland and wetlands since the 1960s. It is closely related to Siam weed, and is one of some 268 species in the genus. This species is

rhizomatous In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

with erect stems to 1.3 m tall, and has stem and leaves covered in rough, bristly hairs. It forms dense rosettes of leaves at ground level, suppressing the germination and growth of other species, at the same time producing

allelochemical Allelopathy is a biological phenomenon by which an organism produces one or more biochemicals that influence the germination, growth, survival, and reproduction of other organisms. These biochemicals are known as allelochemicals and can have ben ...

s which adversely affect the growth of neighbouring plants. The plant dies back annually to its root crown, and survives veldfires over the winter period. Its leaves are light green in colour, lanceolate-elliptic in shape, and measure 8 cm x 2 cm. Leaf margins are serrate, the teeth becoming smaller away from the stalk. Flower heads are surrounded by lanceolate, purplish bracts some 8 mm in length. Flowers are large, pink and showy, and exceed the bracts by 6–8 mm. Mature achenes are black and 5 mm long with a pappus of simple bristles. Moths of the genus '' Adaina'' and in particular '' Adaina microdactyla'' (Hübner), have been investigated as possible biological control agents. Species in the genus include flower borers, leaf feeders and also species that induce stem galls which provide food and accommodation for larvae and pupae. Research at Cedara College of Agriculture has found a rust fungus, ''Puccinia eupatorii'', which invades the seeds and kills the whole plant, including the roots. This rust fungus is specific to ''E. macrocephalum'' and would therefore be ideal as a biological control. Other potential insect agents include a stem-galling thrips, '' Liothrips'' sp., and the moth ''

Cochylis campuloclinium ''Cochylis campuloclinium'' is a species of moth of the family Tortricidae. It is found in Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the L ...

''. Material from this species has been analysed, resulting in the identification of six

triterpene Triterpenes are a class of terpenes composed of six isoprene units with the molecular formula C30H48; they may also be thought of as consisting of three terpene units. Animals, plants and fungi all produce triterpenes, including squalene, the pre ...

s, one

diterpene Diterpenes are a class of terpenes composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being a primary ...

glycoside In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. ...

ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...

, six

steroid A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes t ...

s, one

flavonoid Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

known as cirsilol, and six

cinnamic acid Cinnamic acid is an organic compound with the formula phenyl, C6H5-CH=CH-Carboxylic acid, COOH. It is a white crystalline compound that is slightly soluble in water, and freely soluble in many organic solvents. Classified as an unsaturated carboxy ...

s derivatives. The name ''Eupatorium macrocephalum'' was first published in January 1830 by

Christian Friedrich Lessing Christian Friedrich Lessing (10 August 1809 – 13 March 1862) was a German botanist who was a native of Groß Wartenberg, Niederschlesien. He was a brother to painter Carl Friedrich Lessing (1808–1880), and a grandnephew of poet Gotthold Ephr ...

in Linnaea 5(1): 136–137. 1830. ''"Eupatorium"'' was first used by

Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

to honour 'Eupator Dionysius' aka

Mithridates Mithridates or Mithradates (Old Persian 𐎷𐎡𐎰𐎼𐎭𐎠𐎫 ''Miθradāta'') is the Hellenistic period, Hellenistic form of an Iranian languages, Iranian theophoric name, meaning "given by Mithra". Its Modern Persian form is Mehrdad. It ...

, an ancient ruler of

Anatolia Anatolia (), also known as Asia Minor, is a peninsula in West Asia that makes up the majority of the land area of Turkey. It is the westernmost protrusion of Asia and is geographically bounded by the Mediterranean Sea to the south, the Aegean ...

, while 'macrocephalum' means 'large-headed' and refers to the inflorescence.

Synonyms

*''Campuloclinium macrocephalum var. strigosum'' DC. *''Chromolaena pratensis'' Gardner *''Eupatorium albertinae'' Ant.Molina *''Eupatorium denudatum'' Chodat *''Eupatorium donianum'' Hook. & Arn. *''Eupatorium macrocephalum var. angustifolium'' Baker *''Eupatorium macrocephalum var. stigmatosum'' (Chodat) Hassl. *''Eupatorium macrocephalum var. strigosum'' (DC.) Baker *''Eupatorium stigmatosum'' Chodat llegitimate *''Eupatorium stigmatosum var. subcalvatum'' Chodat *''Eupatorium stigmatosum var. violaceum'' Chodat Eupatorium macrocephalum02.jpg, Eupatorium macrocephalum01.jpg, Eupatorium macrocephalum04.jpg, Eupatorium macrocephalum05.jpg,

References

External links

How to control the weed

Campuloclinium macrocephalum
{{DEFAULTSORT:macrocephalum, Eupatorium Eupatorium