Stem. - Twining and climbing, nearly smooth. Leaves. - Opposite, somewhat triangular-heart-shaped, pointed, toothed at the base. Flower-heads. - Dull white or flesh-color, composed of four tubular flowers; clustered, resembling boneset.

In late summer one often finds the thickets which line the slow streams nearly covered with the dull white flowers of the climbing hemp-weed. At first sight the likeness to the boneset is so marked that the two plants are often confused, but a second glance discovers the climbing stems and triangular leaves which clearly distinguish this genus.