Cirsium praeteriens

Lost thistle, Lost Thistle

Family: Asteraceae · Type: perennial · Native

Conservation status: CNPS 1A

Lost thistle is a rare (CNPS 1A) California native perennial herb found in southern San Francisco Bay Area in Santa Clara County at elevations below 100 meters, though presumed extinct with unknown specific habitat. Flowering from June to July, this plant produces white flowers in large heads 3 to 4 centimeters wide, with distinctive hemispheric involucres. Growing with stout, erect stems that are loosely fine-cobwebby and soft-jointed-hairy, it reaches over one meter tall. Its leaves are elliptic to oblanceolate, deeply divided with narrow, rigidly spreading lobes ending in sharp 5 to 15 millimeter spines, with upper leaves clasping the stem. The plant's phyllaries feature narrowly lanceolate outer segments with spreading spine tips, creating a complex and intricate floral structure.

Habitat: Presumed extinct; habitat unknown

Bloom period: Jun-Jul

Elevation: < 100 m

Bioregions: s SnFrB (Palo Alto, Santa Clara Co.).

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