The first record of this Japanese perennial in North America was a coll. from MART in 1981 (Medley et al. 1985). During the subsequent two decades, it invaded riparian woods along the Big Sandy Rv. and central Ohio Rv. in Ky., W.Va., Ohio and Ind. (Abbott et al. 2004; K, W). More recently, it has been reported from Ill., Mo., Tenn., Ala. and Ga. (K, SE; Seaton 2019). This species is well established in parts of s. Ind. (M. Homoya, pers. comm.), and it has probably been overlooked in many areas of Ky. near the Ohio Rv. and on lowlands elsewhere. At the Boone County Cliffs Nature Preserve, Achyranthes has even spread locally onto uplands along some trails. A. japonica is similar to Iresine rhizomatosa in vegetative form, but it lacks stolons and its leaves are usually less broad-based and less long-acuminate. Plants in North America may all be referred to the relatively glabrous var. hachijoensis Honda. Plants from the area where first discovered in MART have relatively high variability in gross morphology, as compared to downstream populations (Neal 2018). The species is subject to locally intense browsing by deer, but it remains unclear if management with herbivory can be used to reduce it (Seaton 2019). Leaves appear to be edible for humans, at least when cooked; other species in the genus have had much medicinal and nutritional use (e.g. Saraf & Samant 2013). The potential for competitive exclusion by natives such as Laportea and Ageratina also needs to be investigated. Little is known about the dispersal of this species, but it is likely to spread by water, on mammalian fur, on bird feathers and within guts of diverse vertebrates (Janzen 1984, Green et al. 2016, Schwartz et al. 2016a)..