Family
Rubiaceae
Common Name
Warty bedstraw
Regulation
Secondary Noxious, Class 3 in the Canadian Weed Seeds Order, 2016 under the Seeds Act.
Distribution
Canadian: Not present in Canada (Brouillet et al. 2016Footnote 1).
Worldwide: Native to southern Europe and the Mediterranean (Tutin et al. 1976Footnote 2, Hanf 1983Footnote 3). Naturalized in central Europe (Tutin et al. 1976Footnote 2) and in North America, it has been introduced in Michigan (USDA-NRCS 2016Footnote 4).
Duration of life cycle
Annual
Seed or fruit type
Schizocarp, divided into 2 fruits
Identification features
Size
- Fruit diameter: 2.0 - 3.0 mm
Shape
- Fruit is spherical, slightly compressed dorsiventrally
Surface Texture
- Fruit surface is densely covered with tubercles
Colour
- Fruit is pale green to straw yellow
Other Features
- Hilum is located on the ventral side, and is marked by a small knot of tissue
Habitat and Crop Association
Cultivated fields, in scrub and degraded grassland (Hanf 1983Footnote 3).
General Information
Warty bedstraw seed has been introduced into Britain as a contaminant in imported caged bird food (Hanson and Mason 1985Footnote 5). Historically, it was recorded to occur rarely in corn fields (Lindley 1835Footnote 6).
Similar species
Cleavers (Galium aparine)
- Cleavers are a similar size, a similar globose shape and bristles with an inflated base that appear similar to the rough surface of warty bedstraw.
- Cleavers have tubercles that are white and translucent rather than the opaque yellowish tubercles of warty bedstraw. The hilum area is a deep hole rather than the tissue knot of warty bedstraw.
Photos
Similar species
