General:
Annual herb from a slender taproot; stems erect, 15-60 cm tall, simple below, freely branched above, hairy to nearly glabrous.

Leaves:
Basal leaves egg-shaped, pinnately cut or merely toothed, 2-15 cm long, 0.5-5 cm wide, usually lacking at anthesis; stem leaves gradually reduced upwards, entire or rarely toothed.

Flowers:
Racemes numerous, elongate, many-flowered; flower stalks spreading, 2-6 mm long, round in cross section to somewhat flattened, glabrous to finely short-hairy; petals white, 1-3 mm long, conspicuous, as long as or slightly longer than the sepals; sepals about 1 mm long, glabrous or slightly soft-hairy.

Fruits:
Silicles, orbicular to nearly round, 2.5-4 mm long, scarcely margined, shallowly notched (to 0.2 mm), usually glabrous; beaks short, well included within the notch.

Source:  The Illustrated Flora of British Columbia