Cal nearly regular, cleft to near the base into linear or lanceolate lobes; cor 2-lipped, the upper lip concave, entire or emarginate, the lower spreading or deflexed, 3-lobed; stamens 2; pollen-sacs separate, one terminal, transverse or oblique, the other lateral; fr clavate or cylindric, the fertile part elevated on a long stipe-like base; seeds normally 2 per locule, orbicular; ours perennial herbs with narrow, sessile or subsessile, entire lvs and long-peduncled axillary spikes, the fls small, white to violet, each subtended by 3 minute triangular bracts at the base of the cal. 300, warm regions.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.