Arctium lappa is a coarse biennial herb, 1.5 –3 m tall in flower, from a large, fleshy taproot.
Leaves alternate, stalk of lower leaves solid; rosette leaves very large, to 50 cm long, 30 cm wide, base lobed, stem leaves becoming progressively smaller upwards.
Flowers purple, tubular, in heads 3-4 cm wide, round, bracts of head consisting of many layers of hooked spines; heads on stalk 3-10 cm long; inflorescence sticky-hairy, mostly longer than leaves; blooming Aug.-Oct.
Fruit dry, heads of hooked spines disintegrating into individual fruits that stick to fur or clothes when disturbed, seed 0.7 cm.
Wetland status: UPL.
Frequency in NYC: Very infrequent.
Habitat: Roadside weed, often on calcareous soil.