General: Perennial herb from strong rhizomes; stems erect, simple or branched, solitary, smooth except for a few stinging hairs and bristles, 100-300 cm tall.
Leaves: Basal leaves lacking; stem leaves narrowly lanceolate to widely egg-shaped, opposite, the blades 7-15 cm long, coarsely toothed, stalked; stipules 5-15 mm long.
Flowers: Inflorescence of male or female flowers in a 1-7 cm axillary panicle on the same or different plants; corollas lacking; sepals 4, 1-2 mm long; female flowers usually uppermost.
Fruits: Achenes, egg-shaped, flattened, 1.0-1.5 mm long.
Notes: The native taxon is best recognized as a single, highly variable subspecies (Bassett et al. 1974, Boufford 1997).
Moist to mesic streamsides, deciduous woodlands, thickets, avalanche tracks, and alluvial floodplains in the lowland and steppe to lower subalpine zones; ssp. gracilis - common throughout BC; ssp. dioica - rare in SW BC (lower Fraser Valley); ssp. gracilis - N to AK, YT and NT, E to NF and S to ME, NH, NY, PA, NC, MS, LA, TX, NM, AZ, CA, and MX; S America, ssp. dioica - introduced from Europe.
