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

Distribution of Cirsium undulatum
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Species Information

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Illustration Source: The Illustrated Flora of British Columbia

General:
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.

Leaves:
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.

Flowers:
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.

Fruits:
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

Key to the Species and Taxonomic Notes

TAXONOMIC KEY TO CIRSIUM

1. Heads small; involucres 1-2 (rarely 2.5) cm tall; plants introduced.

2. Stems distinctly spiny-winged; plants with perfect flowers C. palustre
2. Stems not conspicuously spiny-winged; plants partly of male and female flowers........ C. arvense

1. Heads large; involucres more than 2 cm tall; plants native (except C. vulgare).

3. Leaves bristly-spiny above, stems distinctly spiny-winged............ C. vulgare
3. Leaves cobwebby to loosely woolly-hairy, woolly or nearly glabrous above, stems not spiny-winged.

4. Pappus of mature seeds exceeding the corollas by 1-10 mm.............. C. foliosum
4. Pappus of mature seeds shorter than the corollas.

5. Heads large; involucres 3-5 cm tall........... C. drummondii
5. Heads small; involucres less than 3 cm tall.

6. Outer involucral bracts more than 2 mm wide at base, slightly if at all hairy and if so, then mainly marginal.

7. Outer involucral bracts strongly glandular; lowermost leaves deeply pinnately lobed more than 1/2 the width of the blade.............. C. undulatum
7. Outer involucral bracts without glands; lowermost leaves shallowly pinnately lobed to 1/2 or less the width of the blade............... C. scariosum

6. Outer involucral bracts less than 2 mm wide at base, densely cobwebby.

8. Corollas white or creamy-white, rarely pinkish; involucral bracts greenish............. C. hookerianum
8. Corollas purplish-red to purplish-pink; outer involucral bracts purplish.

9. Styles exceeding the corollas by at least 3 mm; achenes 5-6.5 mm long; leaves usually lobed more than 1/2 the width of the blade.............. C. edule
9. Styles nearly equal to or exceeding the corollas by only 1.5 mm; achenes 4-4.5 mm long; leaves usually lobed less than 1/2 the width of the blade................. C. brevistylum

Source: 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

Ecology

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
Site Information	Minimum	Average	Maximum
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 Class	C
Number of field plots species was recorded in:	137
Modal BEC Zone Class	BG
All BEC Zones (# of stations/zone) species was recorded in:	BG(57), ESSF(12), IDF(25), MS(10), PP(22)
Source: Klinkenberg 2020

Climate

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.

Status Information

Origin Status	Provincial Status	BC List (Red Blue List)	COSEWIC
Native	S5	Yellow	Not Listed

BC Ministry of Environment: BC Species and Ecosystems Explorer, the authoritative source for conservation information in British Columbia.

Taxonomic and Nomenclatural Links

Flora North America treatment for Asteraceae
Flora North America treatment for Cirsium undulatum
Genetic information (NCBI Taxonomy Database)
International Plant Names Index
Taxonomic Information from the World Flora Online
Integrated Taxonomic Information System

Additional Range and Status Information Links

Burke Museum of Natural History (Washington State records)
CalFlora
Consortium of Pacific Northwest Herbaria records
Jepson Interchange
NatureServe Explorer
USDA

Additional Photo Sources

Images From CalPhoto
UT Austin's Native Plant Database
Google Image Search
Flickr Image Search

General References

Google Scholar Search
Family References
General Botanical References for BC

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2020. E-Flora BC: Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2024-05-06 12:24:06 PM ]

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