Vascular Plants - Asteraceae - Tripleurospermum:
Tripleurospermum inodorum
Page Authors: Don Knoke, David Giblin
scentless false mayweed 
Blooms: June-September
Habit: herb
Duration: annual
Origin: Introduced from Europe
Distribution: Occurring in scattered locations throughout Washington; widely distributed throughout northern 2/3 of North America.
Habitat: Noxious weed in fields and waste ground in eastern Washington
Species Description:

General: Glabrous annual, biennial or occasionally perennial, nearly scentless herb, 1-6 dm. tall.
Leaves: Leaves 2-8 cm. long, bipinnatifid, the ultimate segments mostly elongate, linear or liner-filiform.
Flowers: Heads several or numerous, the disk 8-15 mm. wide; involucral bracts dry, in 2 series, the margins translucent; rays 12-25, white, 6-13 mm. long; disk flowers yellow, 5-toothed; receptacle hemispheric, naked; pappus a short crown.
Fruits: Achenes roughened, with 2 marginal and 1 ventral thickened ribs.
Accepted Name:
Tripleurospermum inodorum (L.) Sch. Bip.
Synonyms:
Chamomilla maritima (L.) K. Koch
Matricaria maritima L. ssp. inodora (L.) Clapham
Matricaria perforata Mérat
Tripleurospermum maritimum (L.) W. D. J. Koch ssp. inodorum (L.) Applequist
Tripleurospermum perforatum (Mérat) M. Lainz

Treated in Flora of the PNW as:
Matricaria maritima
Additional Resources:

PNW Herbaria Specimens: View list of Tripleurospermum inodorum specimens in the Consortium of Pacific Northwest Herbaria database.

WTU Herbarium Specimens: View list of Tripleurospermum inodorum specimens in the WTU Herbarium database.

Washington Flora Checklist: Tripleurospermum inodorum treatment.

E-Flora BC: Tripleurospermum inodorum atlas page.

CalPhotos: Tripleurospermum inodorum images.

USDA Plants Database: Tripleurospermum inodorum.
Additional photographs of Tripleurospermum inodorum:
(click on a thumbnail to view larger photo)

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Craig Althen, 2010

Craig Althen, 2010

Craig Althen, 2010

Craig Althen, 2010

Craig Althen, 2010

Craig Althen, 2010

Craig Althen, 2010
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Washington Native Plant Society
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