Northern Marsh Yellowcress

Foodplant / feeds on
larva of Ceutorhynchus querceti feeds on Rorippa islandica sens.str.

Sometimes thread-like basal nodal roots also develope.

Annual or biennial herb, (10-) 20-70 cm tall, erect, branched, glabrous or slightly hairy below with simple hairs. Lower and middle leaves lyrate-pinnatifid,3-5-jugate, stalked, 5-15 cm long, 1-3 cm broad; terminal lobe subovate, sinuate-toothed; upper leaves deeply toothed to pinnatifid, 1.5-5 cm long, 5-20 mm broad. Racemes 20-30-flowered, up to 20 cm long in fruit. Flowers c. 2 mm across, pale yellow; pedicels up to 10 mm long (about as long as the fruit) in fruit, spreading. Sepals c. 2 mm long. Petals about as long as the sepals, 0.5 mm broad. Siliquae oblong-ellipsoid, 5-10 mm long, 2-3 mm broad, glabrous; style usually c. 1 mm long; seeds many, crowded, c. 0.5 mm in diam., pale brown.

Distribution: Europe and Temperate Asia; widely introduced.

Fl. Per.: April-July.