About Cirsium pumilum (Nutt.) Spreng.
Cirsium pumilum, commonly called pasture thistle, is a North American plant species belonging to the tribe Cardueae in the plant family Asteraceae. This species is native to the northeastern and north-central United States, and also to the Canadian province of Ontario. Cirsium pumilum is a biennial or perennial herb that grows up to 100 cm (40 inches) tall. It blooms once during its lifetime before dying. Its leaf blades can reach up to 30 cm (12 inches) in length, and bear spines ranging from slender to stout in size. Plants of this species usually produce a small number of sweetly scented flower heads. The flower heads contain pink, purple, or white disc florets, and do not produce any ray florets. Two varieties of this species are recognized: Cirsium pumilum var. hillii (Canby) B. Boivin, which occurs in the Great Lakes region and the upper Mississippi Valley; and Cirsium pumilum var. pumilum, which occurs in the northeastern and east-central United States, ranging from Maine to South Carolina and extending west to Ohio.
