P. minor: leaves stalked, broadly ovate or orbicular, entire or slightly crenated, with a minute tooth or gland in each notch; peduncle erect, 4-8 inches high, leafless; flowers drooping, white or pinkish, in a short, loose raceme, the petals ovate or orbicular, free, concave closing over the stamens. - Woods and moist shady places. Fl. July.
P. rotundifolia is a somewhat larger plant, with larger and whiter flowers, chiefly distinguished by having a long protruding much curved style.
P. media is intermediate in size, and is distinguished by having a long protruding nearly straight style.
Both the latter plants are found in woods and moist shady places, but are more rare than P. minor.