Bentham, Cat. Pl. Pyrénées. 95. 1826.
(caudex branched); hirsute.
branched from base, erect to ascending, often decumbent basally, unbranched or branched (few) distally, 1-5 dm.
rosulate; petiole 1-6.2 cm; blade oblanceolate or oblong-elliptic, 1-4.5 cm × 4-14 mm, margins entire, repand, or denticulate.
sessile; blade oblong to deltate-lanceolate, 1-3.5 cm × 3-8 mm, base sagittate or auriculate, margins dentate to denticulate.
much-elongated in fruit; rachis hirsute, trichomes spreading, straight.
horizontal, straight or slightly recurved, (terete), 2.8-5 × 0.3-0.4 mm, hirsute.
sepals oblong, 1.6-2.2 × 0.6-1.1 mm; petals white, spatulate, 1.8-2.8 × 0.8-1.4 mm, claw 1-2 mm; stamens 6; filaments 1.8-2.6 mm, (glabrous); anthers 0.4-0.5 mm.
broadly oblong to ovate, 4-5.5 × 3.5-4 mm, (curved adaxially), apically broadly winged, apical notch 0.2-0.3 mm deep; valves thin, often not papillate, not veined; style (0.6-)1-1.5 mm, well-exserted beyond apical notch.
(dark brown), ovoid, 1.8-2.2 × 1-1.2 mm.
Flowering May-Jun. Gravel mounds, roadsides, abandoned fields, waste grounds, disturbed sites, gardens, hillsides; 0-300 m; introduced; B.C., Nfld. and Labr. (Nfld.); Calif., Colo., Maine, Mass., N.Y., Oreg., Pa., Wash; Europe.
The records from Maine and Massachusetts are based on old collections, and it is not known if
has become established as part of the weedy flora of those states.