M. officinalis: annual or biennial; stem erect, 2-3 feet high; leaflets serrate, truncate, narrowly ovate; stipules setaceous, entire; flowers in lax lateral racemes, yellow; corolla twice as long as the calyx, the wings keel and standard equal; pods ovate-acute, hairy. - Waste places. Fl. June to September.
M. alba: stem erect, 3-4 feet high; leaflets obovate, the upper ones oblong, serrate, obtuse; stipules awl-shaped, entire; flowers white, in lax racemes; corolla twice as long as the calyx, the wings and keel equal, shorter than the standard; pods ovate-obtuse, glabrous. - Sandy and gravelly places. Fl. July to September.