Onopordum acanthium subsp. acanthium

Scotch thistle, Scotch Thistle

Family: Asteraceae · Type: perennial · Not Native

Conservation status: Cal-IPC Yes

Scotch thistle is a naturalized perennial herb found in northwestern California, the Cascade Range, Sierra Nevada, San Joaquin Valley, central western California, southwestern California, and the Modoc Plateau in disturbed sites at elevations below 1,600 meters. Flowering from May to August, this plant produces purple or white flowers in heads with linear phyllaries bearing delicate spines up to 5 millimeters long. Growing up to 3 meters tall with a canescent-tomentose (soft, woolly) appearance, the plant develops robust stems covered in a grayish-white felt-like indumentum. Its large leaves extend 1 to 5 meters long, deeply dentate with 8 to 10 pairs of widely triangular lobes, creating an impressive and imposing silhouette. The fruit is 4 to 5 millimeters long with a distinctive pink to reddish pappus measuring 7 to 9 millimeters.

Habitat: Disturbed sites

Bloom period: May-Aug

Elevation: < 1600 m

Bioregions: NW, CaR, SN, SnJV, CW, SW, MP

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.