V. sativa: annual or biennial; leaves pinnate, tendrilled; flowers axillary, sessile, solitary or in pairs, large reddish-purple; calyx gibbous at the base on one side; seeds smooth. - There are several forms. - Cornfields and cultivated ground. Fl. May, June.
V. lathyroides: annual or biennial; leaves pinnate, ten-drilled; flowers axillary, sessile, solitary, smaller than in V. sativa, purple; calyx equal at the base; seeds granulated. - Dry pastures and roadsides. Fl. April, May.