marsh thistle USDA PLANTS Symbol: CIPA6
U.S. Nativity: Exotic
Habit: Forbs/Herbs
Cirsium palustre (L.) Scop.

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Taxonomic Rank: Magnoliopsida: Asterales: Asteraceae

Appearance
Cirsium palustre is an herbaceous biennial that can grow from 4-5 ft. (1.25-1.5 m) tall. The glabrate stem is winged and armed with spines that result from its decurrent leaf bases. Much of the plant is covered in long, sticky hairs.
Foliage
The leaves are spiny and pinnatifid. They are linear-oblong in shape and have tufts of hairs on the lower surface. The lower leaves are 6-8 in. (15-20 cm) long.
Flowers
This plant usually has many purple flower heads borne on short peduncles that do not reach more than 0.4 in. (1 cm) in length. The ovoid involucre is 0.4-0.75 in. (1-2 cm) across. The bracts are not spine-tipped. The flowers appear in June and July.
Fruit
The mature pappus is white and 0.4 in. (1 cm) in length or less. The small, straw-colored achenes are 0.1 in. (3 mm) long.
Ecological Threat
Cirsium palustre grows best in moist acidic soils. It can be found in any disturbed areas as long as its moisture requirements are met. It is common on roadsides and in wet ditches. It is also somewhat shade tolerant, and therefore can be found in moist woods. A combination of wind dispersal and intermediated shade tolerance makes Cirsium palustre a threat to moist, minimally managed habitats.

Identification, Biology, Control and Management Resources

Selected Images from Invasive.orgView All Images at Invasive.org


Flower(s);
Rob Routledge, Sault College, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Rob Routledge, Sault College, Bugwood.org
Additional Resolutions & Image Usage

Stem(s); mid-stem showing "Internodes (especially upper ones) with continuous or intermittent spiny wings their full length?" (quote source: Michigan Flora)
Rob Routledge, Sault College, Bugwood.org
Additional Resolutions & Image Usage

Stem(s); mid-stem showing "Internodes (especially upper ones) with continuous or intermittent spiny wings their full length?" (quote source: Michigan Flora) ?
Rob Routledge, Sault College, Bugwood.org
Additional Resolutions & Image Usage

Foliage;
Caleb Slemmons, National Ecological Observatory Network, Bugwood.org
Additional Resolutions & Image Usage

Stem(s);
Caleb Slemmons, National Ecological Observatory Network, Bugwood.org
Additional Resolutions & Image Usage

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org
 


State List
This map identifies those states that list this species on their invasive species list or law.


Invasive Listing Sources:
Pacific Northwest Exotic Pest Plant Council, 1998