Page author: David Giblin
Jacobaea vulgaris
tansy ragwort
WTU specimens
Other herbaria

Distribution: Widely distributed on both sides of the Cascades in Washington; British Columbia south to California, east to Idaho and Montana; eastern North America.

Habitat: A weed of pastures, roadsides, forest edges, and other disturbed areas.

Flowers: June-September

Origin: Introduced

Conservation Status: Not of concern

Description:
General:

Biennial or short-lived perennial from a taproot; stems solitary or several, erect, simple up to the inflorescence, 2-10 dm. tall.

Leaves:

Evenly distributed along the stem, only slightly reduced upward, mostly 2-3 times pinnatifid, 4-20 cm. long and 2-6 cm. wide, the lower petiolate and often deciduous, the upper becoming sessile toward to top of the stem.

Flowers:

Heads rather numerous in a short, broad inflorescence, the disk usually 7-10 mm. wide; involucre about 4 mm. high, its bracts about 13, over 1 mm. wide, dark-tipped; rays about 13, 4-10 mm. long.

Identification Notes:

The upright stem covered with large, twice-divided leaves will usually identify this species; the 13 involucre bracts and 13 ray flowers can be helpful.

Accepted Name:
Jacobaea vulgaris Gaertn.

Synonyms & Misapplications:
Senecio jacobaea L. [FNA20, HC]
Additional Resources:

PNW Herbaria: Specimen records of Jacobaea vulgaris in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Jacobaea vulgaris checklist entry.

E-Flora BC: Jacobaea vulgaris atlas page.

CalPhotos: Jacobaea vulgaris photos.

USDA Plants: Jacobaea vulgaris information.

47 photographs:
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