Achillea millefolium var. occidentalis L.
Asteraceae (Aster family)

Introduction to Vascular Plants

Photograph

© Dave Purdy     (Photo ID #83926)


Map

E-Flora BC Static Map

Distribution of Achillea millefolium var. occidentalis
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Species Information

General:
Perennial, aromatic herb, usually rhizomatous; stems erect, slender, 10-100 cm tall.
Leaves:
Fernlike, alternate, stalked below and unstalked above, pinnately dissected, the divisions again dissected.
Flowers:
Heads numerous, in a short, flat or round-topped cluster; involucral bracts dry, overlapping in several series, often dark-margined; ray flowers usually 3-8, 2-3.5 mm long, white to sometimes pink or reddish; disk flowers 15-40, cream colored.
Fruits:
Achenes glabrous, flattened, 1-2 mm long; pappus lacking.
Notes:
Taxonomically, one of our most complex species. Tyrl (1980) presented a sound case for recognizing only a single variable species. I, however, have recognized four, broad ecogeographical forms (sensu Nobs 1960) at the varietal level since these forms are ecologically significant in BC.

1. Leaves grey, long-hairy to woolly; plants usually in and east of the Coast-Cascade Mountains.

2. Involucral bract margins light brown to black; stems usually less than 30 cm tall; plants of the subalpine and alpine zones................. var. alpicola (Rydb.) Garrett

2. Involucral bract margins light brown to straw-coloured; stems usually more than 30 cm tall; plants of the montane and steppe zones........................ var. lanulosa (Nutt.) Piper in Piper & Beattie

1. Leaves usually green, moderately long-hairy; plants of coastal regions.

3. Involucral bract margins dark brown to black; stems 10-40 cm tall........................ var. borealis (Bong.) Farwell

3. Involucral bract margins hyaline to light straw-coloured; stems 30-100 cm tall.................. var. pacifica (Rydb.) G.N. Jones

SourceThe Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
White
Blooming Period:
Late Spring
Fruit/Seed characteristics:
Colour: Brown
Present from Summer to Fall
Source:  The USDA

Habitat and Range

Mesic to dry coastal bluffs, meadows, grasslands, rocky slopes and open forests in all vegetation zones; common throughout BC; N to AK, YT and NT, E to NF and S to FL, TX, CA, and MX. Description

SourceThe Illustrated Flora of British Columbia