Herbaceous perennial; stems mostly single and unbranched, glabrous, slender, 4-10(12) dm tall; leaves opposite, lanceolate to ovate, acute, obtuse to cordate at base, coarsely and unevenly laciniate-serrate, thin, glabrous except sparsely glandular pubescent along main veins, blades to 5-7 cm long, 2-3.5 cm wide, petiole about 1/2 length of leaf blade; inflorescence a loose, few-branched, terminal panicle; peduncles and pedicels glandular pubescent; flowers not showy, short-tubular, bilabiate, dull red to greenish-brown, 7-12 mm long; fertile stamens 4, fifth stamen represented by a small orbicular scale on the lower corolla lip; stigma capitate; fruit a somewhat woody, narrowly ovoid, septicidal capsule, 8-11 mm long; seeds numerous, small, rugose. Flowers July and August.