Ontario Weeds: Stinking mayweed

Table of Contents

1. Name
2. Other Names
3. Family
4. General Description
   • Photos and Pictures
5. Stems and Roots
6. Flowers and Fruit
7. Habitat
8. Similar Species
9. Related Links

Name: Stinking mayweed, Anthemis cotula L.,

Other Names: camomille des chiens, Dogfennel, Stinking chamomille, camomille puante, camomille maroute

Family: Composite or Aster Family (Compositae) 

General Description: Annual, reproducing only by seed.

Photos and Pictures

Stinking mayweed. A. Base of plant. B. Flowering stem.

Stems & Roots: Stems usually erect, but low and bushy-branched, 10-60cm (4-24in.) high, usually hairless in the lower part but finely hairy just below the flower heads; leaves very finely dissected, soft, alternate (1 per node), numerous, or sparse where plants are crowded.

Flowers & Fruit: Flower heads daisy-like, 15-30mm (3/5-1¼in.) across; ray florets white, spreading; disk florets yellow; seeds grayish to brownish, longer than wide, surface rough with lengthwise rows of tiny bumps. All parts of the plant, when crushed, have an offensively disagreeable odour resembling evaporating urine, hence the common name. Flowers from June to late summer.

Habitat: Stinking mayweed occurs throughout Ontario in waste places, along roadsides, around dwellings and farmyards and, occasionally, in cultivated fields.

Similar Species: It is distinguished by its offensive odour, its finely dissected leaves, and its finely hairy stems below the white and yellow flower heads.

Related Links

... on general Weed topics
... on weed identification, order OMAFRA Publication 505: Ontario Weeds
... on weed control, order OMAFRA Publication 75: Guide To Weed Control

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