Leaves are opposite, simple, ovate, 1/2 to 3-1/2 inches long and 1/4 to 1-inch wide, margins coarsely toothed, hairy on both sides with slender leaf stalks. Lowest leaves are usually alternate.
Stem is erect, spreading or curved stem, branches, 8 to 30 inches tall, hairy, with a milky sap.
Flowers are tiny and indistinct flat-top clusters at the terminal end of stems and branches. Fruiting capsule is smooth, seeds are dark brown, gray, or black.
Root is fibrous from a taproot.
Propagation is by seed.