Spreading-hairy perennial, the stems with creeping base and assurgent tips and branches, 0.5-2.5 dm; lvs all opposite, elliptic or elliptic-obovate, narrowed to a ±petiolar base, 1.5-5 נ0.6-3 cm, 1.5-3 times as long as wide, rather finely serrate, the larger ones with mostly 12-20 teeth per side; racemes axillary, pedunculate, spiciform, the pedicels 1-2 mm, surpassed by the small, alternate bracts; cor light blue, sometimes with darker lines, 4-8 mm wide; fr 4 mm, broadly triangular-subcordate, shallowly retuse; style 2.5-4.5 mm; seeds 6-12 per locule, 1 mm; 2n=18, 32-36. Dry fields and upland woods; native of Europe, now well established throughout our range. Apr.-July.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.