Stout, rhizomatous perennial, 1-3 m, stems terete, becoming striate-ridged; lvs broadly ovate, 8-15 נ5-12 cm, abruptly acuminate, broadly truncate at base, the basal angles prominent; racemes numerous from the upper axils, often branched, forming a series of panicles 8-15 cm; fls functionally unisexual, the plants dioecious, perianth white or greenish-white; outer tep narrowly winged along the midrib; styles 3; achenes trigonous, 3 mm, invested by the enlarged perianth, the outer tep broadly winged; 2n=44, 88. Native of Japan, escaped from cult. and well established in our range. (Pleuropterus zuccarinii; Reynoutria japonica)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.