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

Cirsium hookerianum Nutt.
Hooker's thistle (white thistle)
Asteraceae (Aster family)

Introduction to Vascular Plants

© Virginia Skilton  Email the photographer   (Photo ID #26239)

E-Flora BC Static Map
Distribution of Cirsium hookerianum
Click here to view the full interactive map and legend
Details about map content are available here
Click on the map dots to view record details.

Species Information

Click on the image below to view an expanded illustration for this species.



General:
Biennial or short-lived perennial herb from a taproot; stems erect, thick, fleshy, ribbed, soft, sparsely long-hairy to short, curly-haired, 0.2-2.0 m tall.
Leaves:
Mainly basal, these narrowly oblanceolate, nearly entire or pinnately lobed to 1/2 the width of the blade, the segments triangular-lanceolate; stem leaves elliptic-oblong, clasping, up to 30 cm long and 3 cm wide, usually shallowly lobed, margins with a few, weak spines up to 5 mm long, lightly hairy above, densely woolly below.
Flowers:
Heads discoid, 1-6, in a terminal cluster; involucres short-bell-shaped, 2-3 cm tall; involucral bracts densely woolly, linear-lanceolate to lanceolate, not much graduated, middle and outer ones tapering to a slender 3-5 mm, yellow spine, inner ones abruptly sharp-pointed, unarmed, sometimes twisted at the tip; disk flowers white to creamy white, rarely pinkish, 20-26 mm long.
Fruits:
Achenes 5-6.5 mm long, brown with lighter parallel lines; pappus light yellow, 15-20 mm long, shorter than the corollas by 3-5 mm.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Moist to mesic roadsides, meadows and forest openings in the steppe and montane zones; frequent in S BC east of the Coast-Cascade Mountains; E to AB and S to ID, NW MT and WA.

Source: The Illustrated Flora of British Columbia

Ecology

Ecological Framework for Cirsium hookerianum

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

Minimum

Average

Maximum

Elevation (metres) 500 1640 2563
Slope Gradient (%) 0 41 100
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
29 160 350
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 2 6
Modal Nutrient Regime
Class
C
Number of field plots
 species was recorded in:
121
Modal BEC Zone Class
ESSF
All BEC Zones (# of stations/zone) species was recorded in: AT(10), BG(20), ESSF(70), ICH(2), IDF(14), MS(3)

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.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References