Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Genus Description - Cor irregular, inverted so that the 3-lobed morphological upper lip is on the lower (abaxial) side; cor-tube split (between the 2 lobes of the visually upper lip) to below the middle, commonly nearly to the base, often fenestrate on the sides near the base as well; filaments and anthers connate, the lower 2 anthers shorter than the others and bearded at the tip; ovary 2-locular, with axile placentation; style growing up through the anther-tube and pushing out the pollen; stigma 2- lobed; capsule opening at or near the top; ours fibrous-rooted, mostly single-stemmed herbs with the fls in terminal, bracteate racemes, rarely in the uppermost axils. Most of our spp. perennate by short offsets, a few by rhizomes; L. inflata appears to be annual. 300, widespread.