Ascending perennial 3-8 dm; stipules lance-ovate, their tips free beyond the level of adnation to the petiole; lfls oval to elliptic, broadly rounded to retuse at the summit; heads numerous, globose, on peduncles 2-8 cm; fls 7-10 mm, distinctly pedicellate; cal glabrous, the nerves leading to the obtuse sinuses faint or obsolete; cal-lobes linear-subulate, not very unequal, 1.7-2.5 mm, slightly exceeding the tube; cor white and pink, turning brown after anthesis, the standard obovate-oblong, 2 mm longer than the obtuse wings; 2n=16. Native of Eurasia, escaped from cult. throughout temperate N. Amer., commoner northward. Summer.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.