Boehmeria cylindrica is a perennial herb, 40-100 cm tall, nettle-like but unarmed, stem erect, unbranched, opaque, smooth.
Leaves opposite, stalk elongate, blade egg-shaped, base rounded, tip long-pointed, veins palmate at base, margin coarsely toothed.
Flowers greenish, tiny, no petals, sexes on separate plants (dioecious), in dense, rounded clusters along axis of slender, axillary flower spikes; blooming July- Aug.
Fruit dry, 1-seeded (achenes), in pairs, surrounded by old calyx, forming wings; fruiting Aug.-Oct.
Wetland status: FACW+.
Frequency in NYC: Frequent.
Habitat: Wet to moist shady areas, swamp forests, flood plains, edges, stream corridors, soil pH 5.1-7.0.
Notes: Host to larvae of the mourning cloak butterfly, Nymphalis antiopa, (Nymphalidae); question mark butterfly, Polygonia interrogationis and the comma butterfly, P. comma (Nymphalidae), (Tallamy 2003; Pyle 1981).