Plants 6-15 dm, single-stemmed from a crown or short caudex, puberulent in the infl, the herbage otherwise glabrous except that the lvs are gland-dotted; lvs opposite, sessile or subsessile, lanceolate, usually broadly rounded at the base, serrate, acuminate or long-acute, mostly 7-18 נ1.5-5 cm, 2.5-7 times as long as wide, the venation strictly pinnate; invol 4.5-6.5 mm, its bract imbricate, broadly rounded to merely obtuse, villous-puberulent and usually also atomiferous-glandular; fls 5(6), white; 2n=20, 30. Woods, especially in sandy, acid soils; s. N.H. to se. Minn., s. to Ga. and Ark. Aug., Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.