This is widespread on damp soils across eastern North America. No variants are generally recognized (Woods 2005; w), but more northern populations are mostly triploid (2n = 33 versus 22). In Ky. it is generally rare to absent in largely agricultural landscapes on relatively fertile soils, which might be attributed to past disturbances rather than direct influence of the soil. It was used extensively for food by native people, and it is now cultivated in Japen and South Korea, but there is no clear evidence of prehistoric cultivation; see C. W. Cowan in Ford (1985). The oval or globose rhizomatous tubers are 2-10 cm wide, produced in a monoliform chain of 4-10 (Woods 2005). They have a protein content of ca 16.5% (dry weight), but the amino acid balance is suboptimal and there are protease inhibitors that should be denatured by cooking (Brown et al. 2014; and citations).