This perennial is known mostly from relatively base-rich soils in or near the southern Cumberland Plateau of Ky., Tenn., Ga. and Ala. Plants in the Piedmont of N.C. and Va. are disjunct or adventive (W). In Ky. plants are generally found on low wooded slopes, especially along trails or roads. The disjunct record from CHRI (TENN, WIS) is attributed to mislabelling of H. Iltis et al. #23298, 25 Apr 1965; see also Hexastylis ruthiii. E. mercurialina is close to E. ipecacuanhae L. of the south Atlantic Coastal Plain, which was erroneously reported from Ky. by McFarland (1942).