Iva xanthifolia Nutt.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Coarse annual weed 0.5–2 m; stem simple and glabrous below, viscid-villous in the infl; lvs chiefly opposite (only some of the upper alternate), long-petiolate, ovate, often very broadly so, coarsely and often doubly serrate, trinerved or triplinerved, 5–20 × 2.5–15 cm, strigose- scaberulous above, paler and often finely sericeous beneath; infl large, paniculiform, the numerous heads subsessile, not subtended by bracts; invol 1.5–3 mm, its 5 subherbaceous bracts somewhat larger than the 5 more membranous receptacular bracts (like an inner invol) that partly enfold the glabrous or distally hispidulous achenes; cor of the pistillate fls less than 0.5 mm, or obsolete; 2n=36. Bottomlands and moist waste places; Wis. to B.C., s. to Tex. and N.M., and occasionally intr. eastward. Aug.–Oct. (Cyclachaena x.)