Weed Seed: Linaria vulgaris (Common toadflax/Butter-and-eggs)

Family

Plantaginaceae

Common Name

Yellow toadflax

Regulation

Primary Noxious, Class 2 in the Canadian Weed Seeds Order, 2016 under the Seeds Act.

Distribution

Canadian: Occurs across Canada except in NU (Brouillet et al. 2016^Footnote 1).

Worldwide: Native to Europe and temperate Asia (USDA-ARS 2016^Footnote 2) and introduced in North America, Chile, South Africa, Australia and New Zealand (CABI 2016^Footnote 3).

Duration of life cycle

Perennial

Seed or fruit type

Seed

Identification features

Size

• Seed length: 1.7 - 2.5 mm
• Seed width: 1.5 - 2.3 mm

Shape

• Seed round to oval with a wing around the outside; flattened

Surface Texture

• The centre of the seed is covered with tubercles

Colour

• Seed black with bronze highlights

Other Features

• A thin wing surrounds the seed, 0.3 - 1.0 mm wide, minutely reticulated

Habitat and Crop Association

Cultivated fields, old fields, pastures, rangelands, shores, roadsides and disturbed areas (Saner et al. 1995^Footnote 4, Darbyshire 2003^Footnote 5). In Canada, it is a problem in pastures and crops such as wheat, barley, oats, canola and peas (Saner et al. 1995^Footnote 4, CABI 2016^Footnote 3).

General Information

Yellow toadflax was once grown as an ornamental, dye and medicinal plant (Saner et al. 1995^Footnote 4). This species first appeared in Ontario and Quebec at the end of the 19th century and moved into the Prairie Provinces after 1920, through contaminated alfalfa seed and as a garden plant (Saner et al. 1995^Footnote 4). Yellow toadflax is a prolific seed producer and reproduces from both seed and clonal propagation (Saner et al. 1995^Footnote 4).

Similar species

Melancholy toadflax (Linaria tristis)

• This species has rounded, flattened seeds that are a similar size and colour to yellow toadflax.
• Melancholy toadflax may be smooth or have a few tubercles like yellow toadflax, but only on one side of the seed.

Photos

Similar species