Centaurea solstitialis

Yellow star-thistle, Yellow Star-Thistle

Family: Asteraceae · Type: annual · Not Native

Conservation status: Cal-IPC Yes

Yellow star-thistle is a naturalized annual found in California's coastal foothills, Mediterranean province, and western Mojave Desert in disturbed grasslands, roadsides, and woodlands at elevations below 1,300 meters. Flowering from May to October, this invasive plant produces distinctive yellow flowers in spiny, straw-colored heads with central spines 10 to 25 millimeters long. Growing 1 to 10 decimeters tall with a rounded, bushy form, the plant has gray-tomentose stems that are winged and branched throughout. Its lower leaves are deeply lobed or dissected, often withering by flowering time, while upper leaves are linear and long-decurrent with bristly undersides. The fruit is small, 2 to 3 millimeters long, with dark brown outer seeds and fine white pappus bristles.

Habitat: Invasive, roadsides, disturbed grassland or woodland

Bloom period: May-Oct

Elevation: < 1300 m

Bioregions: CA-FP, MP, w DMoj

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