Shrub or half-shrub 1-3 m; stipules slender but persistent; lfls elliptic or lance-elliptic, 1-4 cm, glabrous above, paler and strigose beneath; fls showy, purple, 12-17 mm, borne in numerous lax, axillary racemes; cal-lobes slender, long-pointed, evidently longer than the tube, the 2 upper connate most of their length; 2n=22. Native of China and Japan, rarely escaped from cult. in our range. Sept., Oct.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.