Weed Seed: Galium spurium (False cleavers)

Family

Rubiaceae

Common Name

False cleavers

Regulation

Secondary Noxious, Class 3 in the Canadian Weed Seeds Order, 2016 under the Seeds Act.

Distribution

Canadian: Occurs in AB, BC, MB, ON, QC and SK (Malik and Vanden Born 1988^Footnote 1).

Worldwide: Native to northern Africa, Europe and temperate Asia and naturalized elsewhere (USDA-ARS 2016^Footnote 2).

Duration of Life Cycle

Annual

Seed or Fruit Type

Schizocarp, divided into 2 fruits

Identification Features

Size

Fruit diameter: 1.0 - 2.5 mm

Shape

Fruit globose to oval with a highly visible hole on the ventral side

Surface Texture

The surface is covered in hooked bristles with non-tuberculate bases, fruits occasionally smooth

Colour

Fruit grey-brown with white bristles

Other Features

The hole on the ventral side of the fruit is typically a transverse oval

Habitat and Crop Association

Cultivated fields, forage seed crops, field borders, prairies, gardens, coastal areas, dry open woods, roadsides and waste grounds (Malik and Vanden Born 1988^Footnote 1, Darbyshire 2003^Footnote 3).

General Information

This species thrives in relatively dry and sunny habitats and is intolerant of shade; however, it is very rare on dry prairies that receive little rainfall. Seed dispersal occurs when contaminated straw and manure as well as used animal bedding is spread onto fields. Contaminated harvesting equipment may also disperse seeds along farm roads (Malik and Vanden Born 1988^Footnote 1).

Similar Species

Cleavers (Galium aparine)

Cleavers' fruits have similar globose shape with a hole on the ventral side, grey-brown colour and white bristles.
Cleavers' fruits (diameter: 1.6 - 4.0 mm) tend to be larger than false cleavers, the bristles have tuberculate bases, and the ventral hole tends to be round and deep.