Cal herbaceous, deeply 5-parted; cor tubular or trumpet-shaped, ±distinctly bilabiate, the tube much longer than the lobes; fertile stamens 4, about as long as the tube, the pollen-sacs divaricate; sterile stamen about as long as the fertile ones, usually yellow-bearded toward the tip; style elongate; stigma capitate; fr septicidal; ours (biennial or) perennial herbs, the erect stems arising from a rosette of petioled basal lvs, the cauline lvs oblong to lanceolate or ovate, sessile and often clasping, the upper progressively reduced; fls white to blue-violet or red-violet (red in some extralimital spp.), in terminal paniculiform or racemiform infls. Our spp. all with highly variable lvs, much alike from sp. to sp. 280, mainly N. Amer.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.