wavy-leaved thistle (wavyleaf thistle)
Asteraceae (Aster family)
Introduction to Vascular Plants
Species Information
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.
Illustration
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.
Illustration Source: The Illustrated Flora of British Columbia
Ecology
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 |
||
|
Avg |
Min |
Max |
|
| Elevation
(metres) |
904 | 335 | 2224 |
| Slope
Gradient (%) |
32 | 0 | 78 |
|
Aspect (degrees) |
195 | 30 | 360 |
| Soil
Moisture Regime (SMR) [0 - very xeric; 4 - mesic; 8 - hydric] |
2 | 0 | 7 |
| Modal
Nutrient Regime
Class |
C | ||
| #
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 2013
|
|||
Habitat and 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.Status Information
Taxonomic Keys
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 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
4. Pappus of mature seeds exceeding the corollas by 1-10 mm.............. C. foliosum
5. Heads large; involucres 3-5 cm tall........... C. drummondii 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 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
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 Source: Illustrated Flora of British Columbia |