Sep 5, distinct or nearly so, elongate, unequal in width; cor tubular-campanulate, distinctly irregular, the lobes of the upper lip united to beyond the middle, the tube villous within on the upper side; stamens 4; stigmas 2; fr narrowly ovoid, septicidal; perennial herbs with opposite, serrate lvs and small fls, the long pedicels solitary from the axils, each 2-bracteolate at base. 15, New World.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.