Cirsium fontinale var. fontinale

Fountain thistle, Crystal Springs Fountain Thistle

Family: Asteraceae · Type: perennial · Native

Conservation status: CNPS 1B.1 · Endangered

Fountain thistle is a rare (CNPS 1B.1) California native perennial found in the southwestern San Francisco Bay Area at Crystal Springs Reservoir in San Mateo County, growing in serpentine seeps and streams at elevations of 120 to 150 meters. Flowering from May to August, this plant produces purple-red flowers in nodding heads with spiny, reddish phyllaries up to 20 millimeters long. Growing up to 1.3 meters tall with somewhat reddened stems, it develops an intricate structure with thinly cobwebby leaves covered in velvety hairs. Its leaves are characterized by soft, almost velvet-like surfaces with subtle cobwebby textures that help distinguish this delicate thistle. The fruit is small, measuring 4 to 5 millimeters long, with a distinctive style tip extending 3 to 4 millimeters.

Habitat: Serpentine seeps and streams

Bloom period: May-Aug

Elevation: 120-150 m

Bioregions: sw SnFrB (Crystal Springs Reservoir, San Mateo Co.).

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