Arctium lappa great burdock Asteraceae ARLA*; Q (DeCandido 2001); K, p; R (DeCandido 2001);

  

Arctium lappa.en.wikipedia.org

Arctium lappa.en.wikipedia.org

Arctium lappa is a coarse biennial herb, 1.5 –3 m tall in flower, from a large, fleshy taproot. 

Arctium lappa (greater burdock) solid leaf petiole. © David Fenwick 2017. 10-07-06. APHOTOFLORA. aphotoflora.com

Arctium lappa (greater burdock) solid leaf petiole. © David Fenwick 2017. 10-07-06. APHOTOFLORA. aphotoflora.com (Accessed 9/2017).

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. 

Arctium lappa flower heads. By Glen Mittelhauser. Copyright © 2017 Glen Mittelhauser. New England Wild Flower Society. gobotany.newenglandwild.org

Arctium lappa flower heads. By Glen Mittelhauser. Copyright © 2017 Glen Mittelhauser. New England Wild Flower Society. gobotany.newenglandwild.org (Accessed 9/2017).

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. 

Origin: Eurasia. 

Habitat: Roadside weed, often on calcareous soil.