Weed Seed: Elymus repens (Quackgrass)
Primary Noxious, Class 2 in the Canadian Weed Seeds Order, 2016 under the Seeds Act.
Canadian: Occurs in every province and territory (Brouillet et al. 2016Footnote 1).
Worldwide: Exact native range obscure; however, likely native to northern Africa, Europe, temperate Asia, northern India and Pakistan. Introduced in other parts of Africa, North America, Argentina, Chile, Australia and New Zealand (USDA-ARS 2016Footnote 2). Occurs throughout the United States, except for some regions in the southeast (Kartesz 2011Footnote 3).
Duration of life cycle
Seed or fruit type
- Floret length: 5.0 - 10.0 mm
- Floret width: 1.0 - 1.5 mm
- Floret elongate, concave on palea side, lemma may have a short awn
- Floret surface is smooth with a shiny bump at the base of the lemma
- Floret straw-colour
- The rachilla has parallel sides, with a U-shaped sinus at its base. The palea teeth are short and thick
- No hairs on the callus at the base of the lemma
Habitat and Crop Association
Cultivated fields, pastures, old fields, cattle yards, river flats, roadsides, railway lines, and other disturbed areas (Darbyshire 2003Footnote 4, CABI 2016Footnote 5). A weed of all cultivated crops (Royer and Dickinson 1999Footnote 6).
Quackgrass seed production is relatively low, from 25-400 per stem (Timling 2000Footnote 7). Seed can remain viable in the soil for up to 5 years (Timling 2000Footnote 7). Quackgrass also reproduces rapidly by rhizomes, which can be spread in soil (CABI 2016Footnote 5).
Western wheatgrass (Pascopyrum smithii)
- The two species are similar in size, elongate shape and straw colour.
- Western wheatgrass florets have a transverse groove at the base of the lemma, two lines of hairs on the callus and mixed long and short teeth on the palea. The rachilla is wedge-shaped and arises from a V-shaped sinus. The lemma and palea may be covered in a whitish bloom.
Slender wheatgrass (Elymus trachycaulus)
- The two species are similar in size and elongate shape, although slender wheatgrass appears narrower than quackgrass.
- Slender wheatgrass florets tend to be paler, purple-tinged and with a slight twist. The callus has a line of hairs at the base of the lemma. Palea teeth are fine and close together, and the rachilla is covered in long hairs.
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