P. palustris: annual; stems glabrous, erect, or in dry situations decumbent at the base, much branched, one foot, or in water two feet high; leaves pinnate, with short ovate deeply cut segments, the floral ones twice pinnate; flowers almost sessile in the axils, deep purple-red, the calyx broad, with two broad, short, irregularly cut or jagged lobes, and the upper lip of the corolla with two minute teeth below its middle. - Red Rattle. - Wet meadows and watery ditches. Fl. June, July.
P. sylvatica: steins prostrate or spreading, branching, seldom above six inches long; leaves pinnate, with deeply cut, small segments; flowers sessile in the upper axils, pink-red, the calyx broadly oblong, with five unequal teeth, the upper lip of the corolla with one minute tooth on each side, under the point. - Moist heathy pastures and meadows. Fl. June, July.