Page authors: Ben Legler, David Giblin
Asperugo procumbens
catchweed, madwort
Close up showing the strongly flattened and toothed calyx.

Distribution: Occurring east of the Cascades crest in Washington; Alaska to California, east to the Great Plains, also in eastern North America.

Habitat: Roadsides, fields, irrigation ditches, and other disturbed open areas where moist.

Flowers: May-July

Origin: Introduced from Eurasia

Growth Duration: Annual

Conservation Status: Not of concern

Pollination: Bees, flies


Annual herb with weak scrambling stems bearing minute backwards pointing prickles.


Simple, spoon-shaped, lightly hairy.


Small, blue to violet ,with 5 lobes at tip.


4 tiny nutlets.

Identification Notes:

The strongly toothed calyx that encloses the fruits like a clam shell is distinctive; look also for the small blue flowers and backward pointing prickles on the stems.

Accepted Name:
Asperugo procumbens L.
Publication: Sp. Pl. 1: 138. 1753.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Asperugo procumbens in the Consortium of Pacific Northwest Herbaria database

WA Flora Checklist: Asperugo procumbens checklist entry

OregonFlora: Asperugo procumbens information

E-Flora BC: Asperugo procumbens atlas page

CalPhotos: Asperugo procumbens photos

33 photographs:
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