Weed Seed: Lepidium draba subsp. draba (Heart-pod hoary cress)
Heart-pod hoary cress
Primary Noxious, Class 2 in the Canadian Weed Seeds Order, 2016 under the Seeds Act.
Canadian: Occurs in AB, BC, MB, ON, SK and rare in NS, QC (Francis and Warwick 2008Footnote 1).
Worldwide: Native to northern Africa, central and eastern Europe and temperate Asia. Introduced in North America, South Africa, Australia, New Zealand, Argentina, Chile, and beyond its native range in Europe (USDA-ARS 2016Footnote 2). Found throughout the United States but particularly invasive in the western states (Francis and Warwick 2008Footnote 1).
Duration of life cycle
Seed or fruit type
- Seed length: 2.0 - 2.5 mm
- Seed width: 1.5 mm
- Seed thickness: 1.0 mm
- Seed oval, compressed, the hilum area is flattened
- Seed roughened with faint reticulation
- Seed reddish-brown
- The pods are heart-shaped, 2.5 - 6.0 mm long and 4.0 - 6.0 mm wide, usually hairy
- Seed is ovate in cross section, usually with a furrow between the radicle and cotyledons.
Habitat and Crop Association
Cultivated fields, old fields, gardens, parks, woodlots, orchards, pastures, rangelands, meadows, riparian areas, roadsides, railway lines and disturbed areas (Darbyshire 2003Footnote 3, Francis and Warwick 2008Footnote 1, CABI 2016Footnote 4).
A weed of corn, cereals, potatoes, sugarbeet, sunflower, tobacco, vegetables, alfalfa and vineyards in Europe and a common weed of barley and oats in Canada (CABI 2016Footnote 4).
Heart-pod hoary cress was probably introduced into North America in the 19th century as an ornamental or garden plant (Francis and Warwick 2008Footnote 1).
Globe-pod hoary cress (Lepidium appelianum)
- Globe-pod hoary cress seeds are a similar size, rough surface and oval shape as heart-pod hoary cress.
- Globe-pod hoary cress seeds are a lighter colour and oval-shaped in cross-section with no constrictions like heart-pod hoary cress.
Lens-pod hoary cress (Lepidium chalepense)
- Lens-pod hoary cress seeds are a similar size, roughened surface and oval shape as heart-pod hoary cress.
- Lens-pod hoary cress seeds are a lighter colour with no surface reticulation like heart-pod hoary cress.
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