Macleaya cordata is a perennial herb to 2.5 m tall, aggressively colonial from fleshy rhizomes, stems stout, waxy-pale, sap yellow-orange.
Leaves alternate, stalks long, blade to ca 20 cm long, 24 cm wide, palmately veined, densely wooly white below, dark green above, deeply round-lobed and toothed.
Flowers greenish-white, small, no petals; petals replaced by numerous stamens; wind pollinated (Ronse De Craene 2003); inflorescence large, branched from a central axis, (Bailey and Bailey 1976).
Fruit dry, a capsule with 4-6 black, round seeds with small white-yellow appendages (arils, possible ant dispersed); found in fruit Oct.
Wetland status: UPL.
Frequency in NYC: Very infrequent.
Habitat: Garden escapee found in coal slag fill.
Notes: Contains the toxic alkaloid sanguinarine which is reputed to have antimicrobial properties (Fern, K. 2004; Wikipedia contributors 2006).