A similarly large-fld sp. of the southern plains and Ozarkian region, with glandular-hairy infl and cor, narrower bracteal lvs, and often toothed foliage lvs, scarcely reaches our range as a native, but occasionally escapes from cult.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.