Weed Seed: Cerastium spp. (Chickweed)
Secondary Noxious, Class 4 and Noxious, Class 5 in the Canadian Weed Seeds Order, 2016 under the Seeds Act.
Canadian: The genus includes 18 species found in Canada, distributed across all provinces and territories (Brouillet et al. 2016Footnote 1). Of these, 13 are native to at least some provinces and the other 5 are introduced (Brouillet et al. 2016Footnote 1).
Worldwide: The genus contains about 100 species, originating mainly from north temperate regions of Eurasia and North America and widely introduced around the world (FNA 1993+Footnote 2, Mabberley 2008Footnote 3, USDA-ARS 2016Footnote 4).
Duration of life cycle
Annual or perennial
Seed or fruit type
- Seeds of Cerastium spp. are smaller than commonly encountered Caryophyllaceae genera such as Silene spp. and Stellaria spp.
- Seed size within weedy Cerastium spp. ranges from 0.8 - 1.3 mm
- Seed of Cerastium spp. ovate to wedge-shaped seed; compressed
- Seed of Cerastium spp. is dull and tuberculate; tubercles long with indistinct stellate bases
- Seed reddish-brown
- Hilum is in an open notch at narrow end of seed
Habitat and Crop Association
Cultivated fields, old fields, pastures, rangelands, meadows, gardens, lawns, turf, ditches, roadsides and disturbed areas (Frankton and Muligan 1993Footnote 5, Royer and Dickinson 1999Footnote 6, Darbyshire 2003Footnote 7). In Canada, not a significant problem in cultivated fields where they do not survive tillage, but can become problematic in overgrazed pastures (Royer and Dickinson 1999Footnote 6).
The two most commonly encountered species in Canada are field chickweed (Cerastium arvense) and mouse-eared chickweed (Cerastium fontanum subsp. vulgare). Field chickweed appears to be both native and introduced in North America, while mouse-eared chickweed is native to Eurasia (Darbyshire 2003Footnote 7).
Field chickweed is problematic in overgrazed rangeland and pastures (Royer and Dickinson 1999Footnote 6). Mouse-eared chickweed can be found in cultivated fields (Darbyshire 2003Footnote 7), and the seed may remain viable for up to 68 years (DiTomaso and Healy 2007Footnote 8).
Cerastium spp. seeds have a combination of features that distinguishes them in the Caryophyllaceae:
- Small size
- Opaque reddish-brown colour
- Hilum in an open notch
Common chickweed (Stellaria media)
- Common chickweed seed is reddish-brown colour with a long-tuberculate surface as Cerastium spp.
- Common chickweed seed is slightly larger (length: 1.0 - 1.3 mm) than commonly encountered Cerastium spp. such as C. arvense and C. fontanum subsp. vulgare.
- Common chickweed seeds are rounded with a closed hilum notch, and are translucent reddish-brown.
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