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

Eupatorium perfoliatum f. truncatum] is a form with at least the upper leaves separate, truncate or rounded at the base. A few of my specimens belong to this form. This form was [also] found by Edna Banta in Jefferson County in 1933. It was found in hard, white, moist, clay soil in a flat beech woods on the Schumann farm about 3 mi. northeast of Hanover.