Page authors: Don Knoke, David Giblin
Conyza bonariensis
South American conyza

Distribution: Occurring west of the Cascades crest in lowland western Washington; Washington to California, eastward in the southern U.S. to the Atlantic Coast.

Habitat: Roadsides, fields, wastelots, and disturbed open areas at low elevations.

Flowers: June-August

Origin: Introduced from South America

Growth Duration: Annual

Conservation Status: Not of concern

Pollination: Bees, flies, beetles, wasps


Somewhat hairy, branched annual, 2-10 dm. tall.


Leaves numerous, hairy, dark green, narrow, up to 10 cm. long and 2 cm. wide, often slightly wrinkled or distorted.


Heads numerous in an open inflorescence, borne on the ends of branches; involucre 6-8 mm. high and 1 cm. wide, short-hairy, its bracts narrow and tapering; flowers white, disk flowers 10-20, ray flowers minute and shorter than the pappus.


Achene about one-half the length of the capillary pappus.

Accepted Name:
Conyza bonariensis (L.) Cronquist
Publication: Bull. Torrey Bot. Club. 70: 632. 1943.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Conyza bonariensis in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Conyza bonariensis checklist entry.

OregonFlora: Conyza bonariensis information.

E-Flora BC: Conyza bonariensis atlas page.

CalPhotos: Conyza bonariensis photos.

USDA Plants: Conyza bonariensis information.

3 photographs:
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