Smaller-lvd and more slender than no. 1 [Dracocephalum parviflorum Nutt.], with the bracts of the narrower and less compact infl entire or nearly so; cal 6-8 mm, the tube obviously longer than the teeth; 2n=20. Native of Eurasia, occasionally intr. in our range. June-Aug.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.