Cal regular, the cupulate tube shorter than the 5 narrow lobes; cor slightly irregular, the tube short and broad, the lips widely spreading or the upper arched, the lobes of the upper lip partly united, those of the lower free to the tube; stamens 4, equal; filaments short, inserted in the cor-tube, hairy at base; anthers stout, linear- oblong, opening by short (in our sp.) terminal clefts; style about equaling the stamens; stigma minute; fr ovoid, loculicidal; herbs with opposite lvs and yellow fls, often marked with purple. 20, Mexico and se. U.S.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
