Cirsium palustre (L.) Scop.
marsh thistle
Asteraceae (Aster family)

Introduction to Vascular Plants


© Virginia Skilton     (Photo ID #8861)


E-Flora BC Static Map

Distribution of Cirsium palustre
Click here to view the full interactive map and legend

Species Information

Biennial herb from a fibrous root; stems erect, slender, ribbed, simple or sometimes with ascending branches above, strongly spiny-winged from the winged leaf bases, 0.3-2.0 m tall.
Basal and lower stem leaves narrowly elliptic; middle stem leaves and reduced upper ones lanceolate, pinnately cut to about 1/2 the width of the leaf, the segments narrow, spine-tipped, the bases winged, nearly glabrous to lightly soft-hairy above, lightly to densely long-hairy below.
Heads discoid, several to many, in small, compact clusters terminating the stem or at the ends of branches; involucres egg-shaped to cylindric, 1-1.5 cm tall; involucral bracts sparsely to densely cobwebby, outer ones egg-shaped to lanceolate, often purple-tipped, sticky, usually tapering to a thick, often curved, abruptly sharp-pointed 0.5-1 mm long spine, inner ones progressively longer, unarmed, flat-tipped, pointed; disk flowers purple, 10-12 mm long.
Achenes 2.5-3.5 mm long, straw-coloured; pappus tawny, 9-10 mm long.

SourceThe Illustrated Flora of British Columbia


If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.


Ecological Framework for Cirsium palustre

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres)
916 698 1104
Slope Gradient (%)
10 0 23

Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]

192 40 260
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
4 3 5
Modal Nutrient Regime
# of field plots
 species was recorded in:
Modal BEC Zone Class

All BEC Zones (# of stations/zone) species was recorded in

ESSF(3), ICH(4), SBS(1)

Habitat and Range

Moist meadows and forest openings in the lowland zone; infrequent throughout BC south of 55degreeN; introduced from Europe.

SourceThe Illustrated Flora of British Columbia

Taxonomic Notes

The Invasive Plant Council of British Columbia lists this species as one of BC's most unwanted species. Visit their web site.