Weed Seed: Silene latifolia subsp. alba (White cockle)

Family

Caryophyllaceae

Synonym

Silene pratensis

Common Name

White cockle

Regulation

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

Distribution

Canadian: Occurs in AB, BC, MB, NB, NL, NS, ON, PE, QC and SK (Brouillet et al. 2016^Footnote 1).

Worldwide: Native to northern Africa, parts of temperate Asia and Europe (USDA-ARS 2016^Footnote 2). Naturalized in other parts of temperate Asia, Australia, New Zealand, North America and southern South America (USDA-ARS 2016^Footnote 2). Abundant in the northern United States, particularly east of the Dakotas, infesting 30% of the legume acreage in some areas (McNeill 1977^Footnote 3).

Duration of life cycle

Biennial to short-lived perennial

Seed or fruit type

Seed

Identification features

Size

Seed length: 1.3 - 1.5 mm
Seed width: 1.0 - 1.3 mm

Shape

Seed inflated D-shaped, with the hilum in the middle of the flat edge

Surface Texture

Surface is densely covered with randomly arranged tubercles

Colour

Greyish-brown to bluish-grey
Immature seeds are reddish

Other Features

A prominent collar extends one-half to two-thirds around the hilum, forming a distinctive 'open mouth'

Habitat and Crop Association

Cultivated fields (especially legume forage crops and small grains), gardens, pastures, orchards, fencerows, old fields, railway lines, roadsides and disturbed areas (McNeill 1977^Footnote 3, Darbyshire 2003^Footnote 4).

General Information

White cockle prefers full sun and rich, well-drained soils (McNeill 1977^Footnote 3). This species reproduces mainly by seed, producing up to 24,000 seeds per plant, but can also propagate from root fragments (McNeill 1977^Footnote 3).

Similar species

Night-flowering catchfly (Silene noctiflora)

Seed has similar D- shape, size and randomly arranged tubercles as white cockle.
White cockle seed is usually covered in a whitish bloom, has an 'open mouth' hilum, with a round, inflated shape. Night-flowering catchfly seed may have a yellowish bloom, or is reddish. The hilum is bordered by two small pads and the seed does not appear inflated.

Bladder campion (Silene vulgaris)

Similar shape and size as white cockle.
White cockle seed is usually covered in a whitish bloom, has an 'open mouth' hilum, with randomly arranged tubercles and an inflated shape. Bladder campion seed is usually greyish. The hilum is bordered by two large pads, with surface tubercles in rows and is an angular shape.