Annual or biennial herb with a long taproot 10 - 40 cm tall Leaves: alternate, pinnately divided, short-stalked, 4 - 5 cm long, to 2 cm wide, oblong. Leaf segments opposite, linear-elliptic to linear-oblong, tips pointed, sometimes bearing a few teeth along the margins. There is a foul odor when the leaves are crushed. Flowers: in a loose, 1 - 4 cm long branched cluster (raceme), which is borne opposite a stem leaf. Sepals four, oval. Petals four, white to greenish, tiny, barely exceeding sepals. Stamens six, sometimes two. Fruit: a short, round pod, tightly clustered, occurring in pairs, 1.7 - 3 mm long, flattened, coarsely wrinkled, notched at top and bottom, without a wing. Stems: multiple from base, decumbent or ascending, rounded, branching from a central point, sometimes thinly hairy.
Similar species: No information at this time.
Flowering: late June to mid-August
Habitat and ecology: Introduced from Europe. Rare in the Chicago Region. This weed has been found growing in a flowerbed, a vacant lot, the edge of a lawn, and in a shaded nursery area.
Occurence in the Chicago region: non-native
Etymology: Coronopus comes from the Greek word korone, meaning crown, and pous, meaning foot, which refers to the cleft leaves. Didymus means "in pairs."
Foetid annual or biennial, thinly hairy, much-branched, spreading or ascending, 1-4 dm; lvs oblong, 1-3 cm (including the short petiole), pinnatifid, the segments entire or with a few deep teeth; racemes rather loose, 1-3 cm, the mature pedicels slender, 2 mm; fr didymous, distended over the seeds, coarsely wrinkled on the surface, 1.7-3 mm, cordate at base, evidently notched at summit, the style and stigma included in the notch; 2n=32. Native of S. Amer., established as a weed throughout our range and elsewhere, especially southward. Summer. (Carara d.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.