Family
Asteraceae
Common Name
British yellowhead
Regulation
Prohibited Noxious, Class 1 in the Canadian Weed Seeds Order, 2016, 2016 under the Seeds Act. All imported and domestic seed must be free of Prohibited Noxious weed seeds.
Distribution
Canadian: Occurs in ON and QC (Brouillet et al. 2016Footnote 1).
Worldwide: Native to Europe and temperate Asia. Introduced to Canada and the United States (NY, DC). May be an occasional escape rather than truly established in North America (eFloras 2016Footnote 2).
Duration of life cycle
Perennial
Seed or fruit type
Achene
Identification features
Size
- Achene length: 1.0 - 1.5 mm
- Achene width: 0.2 - 0.5 mm
- Pappus length: 4.0 - 6.0 mm
Shape
- Achene is oblong with flat ends
Surface Texture
- Surface of achene has several longitudinal ribs, is rough and covered with thin white hairs
Colour
- Achene is medium brown
Other Features
- Pappus hairs are barbed, appear to be persistent.
- Thin, distinctive ring of white tissue at the base of the achene.
Habitat and Crop Association
Wet places (e.g., streambanks, ditches, marshes, wet woods and grasslands), nurseries, roadsides and waste places (FNA 1993+Footnote 3, CABI 2016Footnote 4). Its roots and rhizomes are known to contaminate Hosta spp. root systems (CABI 2016Footnote 4).
General Information
Introductions of British yellowhead into Canada and the eastern United States started in approximately the 1920s and have mostly occurred through the nursery trade. Populations either did not persist or are small and contained (Lehtonen and Schall 2000Footnote 5).
In the Netherlands, where this species is known to be associated with Hosta spp., it has been subject to aggressive control since 2000 (Lehtonen and Schall 2000Footnote 5).
Similar species
Common groundsel (Senecio vulgaris)
- Similar size, oblong shape, hairs on surface as British yellowhead.
- The surface hairs of common groundsel are short and thick; the hairs of British yellowhead are longer and thin. Common groundsel does not have a white ring of tissue at the base of the achene.
Photos
Similar species
