This is concentrated on strongly acid soils in Appalachian regions, but with outlying populations west to the Ozarks. In Ky. it only occurs in the Cumberland Mts. plus some extension west to the Cliff Section of MCRE and WHIT. There is almost no overlap in range with stipulata. G. trifoliata tends to occur in less xeric sites than stipulata, but both species are concentrated in thin woods and edges. Both species have had traditional human use as powerful laxatives and emetics (Stanhope 1856, Manchey 1933); however, there appears to have been no modern research into the relevant chemistry. Controversy over the generic name has been resolved (W).