This tetraploid (2n = 40) is concentrated in midwestern and mid-Atlantic regions (Owenby 1944; F). It is the only Polygonatum known in Mo. (Y). It occurs on relatively mesic fertile sites, more often on floodplains than typical diploid biflorum. Although prospering locally in somewhat disturbed habitats, such as low-maintenance roadsides through woodland, plants are generally rare in agricultural landscapes, perhaps due to past grazing and rooting by livestock; see also Howe & Bratton (1976). Despite several differences in average dimensions (F, W), this taxon may often be indistinct from typical biflorum (Cr, FNA 26, W). Variety status has often been preferred, but further research is still needed to clarify phylogeny and nomenclature (Floden 2017; and pers. comm.). P. commutatum differs from typical biflorum in its greater average size, ca. 20-90 cm in height (versus usually 6-20 cm). Leaves are subpetiolar, clasping to sheathing at base (versus virtually sessile, not clasping), 3.5-13 cm wide (versus 1.2-6 cm), the larger ones with ca. 110-220 nerves (versus 50-120) and more corrugated. Peduncles have 2-10 flowers (versus 1-5); the perianth is typically 17-20 mm long (versus 7-15 mm), with 5-6.5 mm lobes (versus 3-4 mm).