Cirsium horridulum is a biennial herb, 0.2-1.5 m tall, stems stout, webby-hairy when young, often unbranched.
Leaves alternate, very spiny, pinnately divided, margin very spiny, usually broad, base clasping stem, first year rosette leaves hairy above, wooly-hairy below.
Flowers pale yellowish or purple, all tubular, base of flower head 3-5 cm long, outer bracts pinnate-spiny and spine-tipped; blooms May-Aug.
Fruit dry 1-seeded achene 0.4-0.6 cm.
Wetland status: FACU-.
Frequency in NYC: Very infrequent.
Habitat: Open habitats, often sandy soil, along brackish or freshwater marshes or creeks.
Notes: Attractive to many insects as larval or adult food or as pollinators (Gann et al. 2007).