Polygonum hydropiperoides Michx. Polygonum hydropiperoides Michx., Fl. Bor.-Amer. 1: 239. 1803 sec. Castillejos-Cruz & Solano 2008=Polygonum barbatum Walter, Fl. Carol.: 131. 1788 syn. sec. ???=Polygonum mite Pers., Syn. Pl. 1: 440. 1805, nom. illeg. syn. sec. ???