Perennial from coarse, running, rhizome-like roots, erect, usually simple-stemmed, 1-3 m, puberulent in the infl, often otherwise glabrous or nearly so; lvs alternate, numerous and crowded, lanceolate or lance-linear, to 1.5(-2) dm, sessile or subsessile; racemes terminal, elongate; fls many, pink-purple (white); pet 1-2 cm, short-clawed; hypanthium not prolonged beyond the ovary; style basally hairy; stigma deeply 4-cleft; fr 3-8 cm; 2n=36, 72, 108. Many habitats, especially moist soils rich in humus, often abundant after fires; circumboreal, s. to N.J., O., n. Ill., Nebr., and N.M. June-Sept. (Chamaenerion a.; C. spicatum) Ours represent the tetraploid var. canescens A. W. Wood, in contrast to the more northern, diploid var. angustifolium.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.