This perennial is widely established across northern North America, but rare to absent in southeastern states. Although often considered alien, there may have been native plants in the northeast (Cr). It has been reported from a few western counties (CARL, GRAV, HICK, etc.) by Mohlenbrock et al. (1966) and perhaps others (CASE, FAYE); see Gray (1864), BA, Gm and M. However, verified colls. have not been located. V. cracca has often been confused with villosa and dasycarpa, but differs as follows (F, Isely 1990): calyx ca. 2.5-4 mm long (versus 5-6 mm), the upper side of gradually rounded, not gibbous (versus gibbous or saccate); lower calyx teeth lance-attentuate (versus linear-aciculate); upper calyx teeth short and broad (versus lanceolate); corollas mostly 9-13 mm long (versus 12-16 mm), with L/W ca. 3-3.5 (versus 4-6); expanded portion of standard as long as narrowed portion (versus less than half as long); perennial (versus annual or biennial).