Lycopus virginicus is a perennial herb, 20-80 cm tall, stems 4-sided, from slender underground stems (stolons), stems square with blunt angles, freely branched, usually finely hairy.
Leaves opposite, 5-12 cm long, 2-5 cm wide, egg- to lance-shaped, tip pointed, margin coarsely toothed to slightly below middle of blade, margin near base untoothed, concave, extending down short stalk as narrow wings, surface dark green or purplish, long-hairy.
Flowers white, corolla 4-lobed, upper lobe often notched, petal lobes almost regular, ca 1 mm long, calyx 0.1 cm long, stamens about as long as corolla; flowers embedded in small bracts, in tight axillary clusters; blooms and fruits July-Oct.
Fruit dry, 4 nutlets, 0.2 cm long, 0.1 cm wide, longer than persistent calyx, wedge-shaped, one side flat, other side rounded, top symmetric.
Wetland status: OBL.
Frequency in NYC: Infrequent.
Habitat: Emergent marshes, swamp forests, pond edges, wet soil, pH 5-5.3, tolerant of shade, intolerant of salt.
Notes: Toxic (Cowperthwaite 2003), but has been used as a medicinal (Fern, K. 2004).