E-Flora BC: Electronic Atlas of the Flora of British Columbia

Cirsium undulatum (Nutt.) Spreng.
wavy-leaved thistle (wavyleaf thistle)
Asteraceae (Aster family)

Introduction to Vascular Plants

© Bryan Kelly-McArthur  Email the photographer   (Photo ID #64062)

E-Flora BC Static Map
Distribution of Cirsium undulatum
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Species Information

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Biennial or short-lived perennial herb from a taproot; stems erect, slender, woody, white- to grey-woolly, simple or few branched, 0.3-1.2 m tall.
Basal leaves nearly entire or pinnately lobed, 3.0-7.0 cm long, both surfaces grey-woolly; lower stem leaves oblanceolate or linear-elliptic, tapering to the base, up to 40 cm long and 10 cm wide, lobed to 2/3 the width of the blade, marginally spiny with strong, yellow spines 1-5 mm, densely grey-woolly below, thinly woolly above; the uppermost leaves reduced, lanceolate, less deeply lobed, clasping.
Heads discoid, solitary, terminating the stem or the few branches; involucres bell-shaped or near globose, 2-3 cm tall; involucral bracts graduated, the outer ones strongly glandular, egg-shaped to narrowly egg-shaped, with a strong, yellow, diverging 2-5 mm long spine, inner ones unarmed, the tips often crisped and minutely fringed with small hairs, or tattered, spreading or recurved above the middle, slightly if at all glandular; disk flowers purple to pinkish-purple, rarely white, 20-30 mm long, the tubes 12-21 mm long, the lobes 6-8 mm long.
Achenes 4-8 mm long, brown; pappus white, 2-3 cm long, shorter than the corollas by 5-10 mm.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Dry open grasslands, shrublands and open forests in the steppe and montane zones; common in SC and SE BC; E to MB and S to NM and AZ.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Cirsium undulatum

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) 335 904 2224
Slope Gradient (%) 0 32 78
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
30 195 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 2 7
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: BG(57), ESSF(12), IDF(25), MS(10), PP(22)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References