Restricted almost entirely to sandy, gravelly or rocky soils on the dry banks or rocky bluffs along streams and about lakes. Where it is found it is usually frequent to common and may be found in suitable habitats along streams for miles and may be absent in intervening habitats.
Stems erect, usually several, 4-8 dm, glandular- puberulent in the infl, glabrous or often villous below; cauline lvs lanceolate to oblong, 5-12 cm, toothed or subentire, rounded or truncate at base; cal at anthesis 4-7 mm, at maturity more than half as long as the fr; cor 2-3 cm, the tube very slender, not widened distally, pale violet outside, pale-hairy inside but lacking purple lines, the mouth ±closed by the arched base of the lower lip, the lobes white. Dry woods and fields; Que. and Me. to Mich. and Wis., s. to Va. and Ky. May-July.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.