Much like P. verticillatum var. verticillatum, but the lvs softer and less veiny, and the cal-teeth longer and sharper, 1-1.5 mm; invol bracts lanceolate, acuminate to aristate; 2n=78-80. Dry upland woods; s. N.H. to Ga., w. to Ill. (P. leptodon)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
