Leaf blades 3-nerved from bases, 20-43 × 13-35 mm, broadest near bases, bases broadly subtruncate to broadly cuneate, margins crenate. 2n = 20, 30. Flowering Jul-Aug. Moist, low ground, roadsides, margins of ponds, sandy soils; 10-200+ m; Ala., Ark., Del., Fla., Ga., Ind., Ky., La., Md., Mass., Miss., N.J., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Va., W.Va. Variety rotundifolium includes both sexual diploids and apomictic polyploids, which are morphologically not distinguishable. The sexual diploids are somewhat more restricted geographically, occurring in a band across northern Florida and southern Georgia.