From Flora of Indiana (1940) by Charles C. Deam

An infrequent plant but usually frequent to common where it is found. It generally occurs in open, springy places, although in some of the southern counties in the Illinoian area it is found in hard, white clay soil in low, flat, beech and sweet gum woods, where it is usually common. Wherry divides the species into two varieties as follows: Nodes few (about 7-15) and often remote; upper leaves tending to become broadly lanceolate and cordate; blooming chiefly in early summer = P. maculata var. odorata (Sweet) Wherry. Nodes numerous (about 15-30), and often crowded; upper leaves tending to become linear- or oblong-lanceolate; blooming chiefly in late summer = P. maculata var. pyramidalis (Smith) Wherry. The first variety is the northern form and extends southward in Indiana to Jennings County. The second variety is the southern form of the species and extends northward in Indiana to Jackson and Wayne Counties.