The genus Arctium Linnaeus

Remark The words or terms in red (actually dark orange) in the text are defined in a glossary.


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The genus Arctium has discoid flower heads, and globular involucres. The flowers, usually purple, are followed by roundish many-seeded burs. The involucral bracts. (phyllaries) are attenuate to long, stiff, with hooked tips. The seeds have a pappus. The leaves are large and coarse. The Arctium species flower from July through October. The genus belongs to the Asteraceae family.

Arctium is a biennial native in temperate Europe and Asia and is an introduced and mostly weedy plant in North America. Its taxonomy is still evolving. A large number of species have been placed in genus Arctium at one time or another, but most of them are now classified in the related genus Cousinia. The precise limits between the two genera are hard to define. Up to four species and two hybrids are usually recognized in Québec:

Plants of the Arctium genus are sometimes confused with plants of the Xanthium genus, due to some similarity in the fruits, and Rheum genus (the genus of Rhubarb) due to some similarity in the leaves, but they are in fact quite easy to differentiate from one another with the minimum of attention.

The two species, simple enough to recognize and agreed upon by most taxonomists are Arctium lappa and Arctium minus, the only two that will be dealt with in theses pages. Both species are similar in appearance and were introduced from Eurasia. It is a biennial weed that can grow up to 2 meters tall. The roots of Arctium lappa are widely used for herbal medicinal purposes such as blood cleansing, urinary tract infections, skin ulcers and arthritic conditions and first year roots known as Gobo are eaten as a vegetable in Japan. This invasive species can also taint milk if animals have grazed large quantities. Arctium seeds have also been problematic for livestock because of the hooked seeds. They become entangled in animal hair for several weeks before drying out and falling off. The hooked seeds are able to disperse quite readily. It is largely found in disturbed soils along roadsides, streambanks, creeks, farms and grassland areas.

Name

The genus name is said to come from the Greek αρκτοσ (arktos), meaning bear in reference to the shaggy burrs.

Remarks

Arctium has been used in folk remedies for various ailments. It may have hypoglycemic activity and therefore have potential as a medicine for diabetes. The Meskwaki Indians used Arctium lappa root as an aid in childbirth, and 17th Century Europeans used it as a putative remedy for venereal disease.

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