Cal 10-13-nerved, often 2-lipped, the lobes shorter than the tube; cor ±distinctly bilabiate, the upper lip entire or merely emarginate, the lower 3-lobed; stamens 4, commonly exsert, straight and divergent, the pollen-sacs parallel; rhizomatous herbs with linear to ovate lvs and small fls in crowded or head-like cymes terminating the stem and branches or also sessile in the axils of the upper lvs; cor purple to white, the lower lip commonly purple-spotted. Fl in mid- and late summer. (Koellia) 20, N. Amer. Spp. 4-6 confluent.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.