Stems woody at base, freely branched, 2-4 dm, glabrous; lvs subsessile, ovate or deltoid-ovate, 2-4 cm, acute, glabrous, commonly with a few teeth; axillary cymes 3-9-fld, usually shorter than the subtending lf, mingled with linear bracts 1 mm; terminal cymes larger, more loosely branched; cal glabrous, 3 mm; cor rose-purple to white, 6-8 mm. Dry or rocky woods; s. N.Y. and Pa. to Ind., Ill., and Mo., s. to S.C. and Okla. Aug.-Oct.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.