Cal campanulate, somewhat irregular, the lobes longer than the tube, the 2 lower shorter and broader than the 3 upper; cor bilabiate, the tube conspicuously gibbous on the upper side near the base, the lower lip deflexed, its median lobe shorter than the lateral ones, folded longitudinally into a pouch enclosing the 4 stamens, the upper lip erect, 2-lobed, bearing a double ridge at its base or at the sinus; pollen-sacs divaricate; fifth stamen vestigial; style elongate; stigma capitate or slightly 2-lobed; fr septicidal, the valves cleft at the tip; seeds few, convex on one side; annuals or winter-annuals, the cauline lvs opposite, the uppermost often whorled; fls often bicolored, in whorls of 2-8 from a few upper nodes. 17, temp. N. Amer., espec. Calif.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.