Cirsium arvense (Linnaeus) Scopoli

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


sep_18_04.gthmb can't be loaded. Cirsium arvense is a persistent perennial that grows vigorously, forming dense colonies and spreading by roots growing horizontally that give rise to aerial shoots. Plants generally grow one to four feet tall, but on occasion may grow more than six feet tall and branch freely. Stems are smooth, mostly without spiny wings, green and glabrous. Flower heads are numerous, small, and almost spineless. Flowers are purplish lavender or, less commonly, white.

Cirsium arvense is native to southeastern Europe and the eastern Mediterranean area. It has spread to most temperate parts of the world and is considered an important weed in thirty-seven countries. It is particularly troublesome in cooler areas of North America, extending from coast to coast in both Canada and the United States. It was introduced into North America in the seventeenth century by French settlers as a contaminant in crop seed. It occurs in nearly every upland herbaceous community within its range, and is a particular threat in grassland communities and riparian habitats.

Numerous variants of Cirsium arvense have been named based upon such features as pubescence, extent of leaf division, and spininess. Although extreme variants can be strikingly different, they are connected by such a web of intermediates that there seems to be little value in according any of them formal taxonomic recognition.

Cirsium arvense belongs to the Asteraceae family. It has a chromosome number (n2) of 34.

Name

In Greek κιρσιον (kirsion) is the name of a Thistle that was used to heal varicose veins, and κιρσοσ (kirsos) means varicose vein, kirsion being then the (bygone) remedy of kirsos. As for Thistle it is the common vernacular of most Cirsium species (and of some Carduus species too).

In Latin arvum means land that can be ploughed, field and arvus means that can be ploughed; the derived arvense epithet applies quite well to the species that is found in fields and crop land.

Common names

Some of the vernacular names of Cirsium arvense are: Canada Thistle, California Thistle, Creeping Thistle, Corn Thistle, Cursed Thistle, Green Thistle, Hard Thistle, Small-flowered Thistle, Way Thistle, Perennial Thistle and Field Thistle.

Synonyms

Cirsium arvense has also been known as:

Identification

draw.jpg can't be loaded. Cirsium arvense could be confused with various Carduus species, and with Cirsium vulgare, but Cirsium arvense is the only Cirsium and the only Thistle species with male (only with stamens) with female (only with anthers) flowers on separate plants, male and female flowers that can be readily distinguished, the later by the absence of pollen.

Furthermore, the stems of Cirsium arvense are spineless unlike Cirsium vulgare and Carduus nutans.

Description

Cirsium arvense is a 1 to 4 ft (30 to 120 cm) tall plant with green foliage. It forms an extensive underground root system that sends up numerous erect stems each spring.

Stems

Leaves

Flower heads

Fruits

Habitat

Cirsium arvense grows on a variety of soil types. It grows on all but waterlogged, poorly aerated soils, including clay, clay loam, silt loam, sandy loam, sandy clay, sand dunes, gravel, limestone, and chalk, but not peat. It does well on deep, well aerated, moist loam soils, but is known to grow in dry habitats and on sandy soils. It may also grow on stream banks, in meadows, and even in wet ditches, but it will not survive in saturated soil. It is intolerant of shade, requiring good light conditions for aggressive growth.

Distribution

map_na.jpg can't be loaded. Native to southeastern Europe, the eastern Mediterranean, and possibly northern Europe, western Asia, and northern Africa, Cirsium arvense has now a near global distribution between 37 and 58 to 59 degrees North in the northern hemisphere, and at latitudes greater than 37 degrees South in the southern hemisphere, exclusive of Antarctica. It occurs throughout Europe, northern Africa, western and central Asia, northern India, Japan, China, northern North America, South Africa, New Zealand, Tasmania, and southeastern Australia. The map show the USA States and Canadian provinces and territories provinces where the plant can be found.

Notes

Cirsium arvense infests many habitats such as cultivated fields, roadsides, pastures and rangeland, railway embankments, and lawns. In the US, it is a major pest in streamside grasslands from the Pacific Northwest eastward to the plains. It also invades moist prairies. Once established, it spreads rapidly by horizontal roots, up to several meters per year. The extensive horizontal root system assures long-term persistence and spread by vegetative means. A segment of root as small as 1/8 to 3/8 inch (3 to 6 mm) in length and 1/16 inch (1 mm) in diameter is able to propagate a new plant and is easily spread with plant material or by equipment. Sheep and cattle graze on Cirsium arvense when the plants are young and tender, helping to deplete the root reserves.

American Indians purportedly used an infusion of Cirsium arvense roots for mouth diseases. The Chippewa considered it to be a tonic, diuretic and astringent. Young shoots and roots, used in the same ways as asparagus, and were eaten in Russia and by Native Americans. The nectar of the flowers is also said to make good honey. The plant has been used by native people in the northeastern United States in remedies for worms and poison-ivy (Toxicodendron radicans) and was used to make a mouthwash for children, a treatment for tuberculosis, and a tonic for gastrointestinal ailments.

Gallery

The photos of the gallery were taken either with one of the following: The title in the window shows the date when the picture was taken, i.e. jan_30_06... would mean that the photo was taken on the 30th of January, the 06 is for the 6th picture taken that day.

The month, day and picture number might be followed by a letter:

Click on the thumbnails to get larger view. The original photos are usually in TIFF format, the photos shown are generally in JPEG format, usually of dimensions one half (surface one quarter) for loading time reduction.

Plants, stems

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Leaves

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Flower heads

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