Cirsium douglasii var. breweri
Brewer's swamp thistle
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Family: Asteraceae · Type: Herb · Native
Cirsium douglasii var. breweri (Brewer's swamp thistle) is a native California herb in the Asteraceae family, recognized by shorter stature, shallowly lobed cauline leaves, and smaller spines vs var. douglasii.
Brewer's swamp thistle is a California native perennial found in the Klamath Ranges, northern Coast Ranges, Cascade Range, northern Sierra Nevada, and Modoc Plateau in wet habitats, occasionally on serpentine soils, at elevations of 1,000 to 2,200 meters. Flowering from June to September, this thistle produces purple flowers in heads 2 to 3 centimeters wide with prominent spiny bracts. Growing with robust stems up to 2.5 meters tall, it forms dense clusters in marshy or damp meadow environments. Its cauline leaves are only shallowly lobed, with small spines less than 7 millimeters long, giving the plant a somewhat soft appearance despite its thistle characteristics. The plant's ability to thrive in wet and occasionally serpentine environments makes it a distinctive component of northern California's wetland ecosystems.
Identification and appearance
Key characters: 30 sympatric species; shorter stature, shallowly lobed cauline leaves, and smaller spines vs var. douglasii
Habitat and range
Habitat: Wet places, occasionally on serpentine
Elevation: 1000-2200 m
California counties: Humboldt, Butte, Lake, Lassen, Modoc, Nevada, Shasta, Siskiyou, Sonoma, Trinity, Mendocino, Tehama, Glenn, Plumas, Colusa, Napa, San Benito
Outside California: southern Oregon
Bloom period
Cirsium douglasii var. breweri blooms Jun-Sep.
How to tell it apart
vs Carduus: Cirsium has fluffy, feathery seed tufts; Carduus has rough bristles or no pappus and continuous spiny wings down the stem.; vs Silybum: Cirsium leaves are plain green; Silybum has bright white marbling along the leaf veins.; vs Sonchus: Cirsium has thistle-type flowers with spine-tipped bracts; Sonchus has dandelion-like flowers and milky sap.; vs Cynara: Cirsium heads are 1-6 cm across; Cynara heads are massive (4-15 cm, tennis ball sized) with fleshy bases.; vs Centaurea: Cirsium has linear bracts without appendages; Centaurea bracts have fringed or comb-like tips.
Frequently asked questions
Is Cirsium douglasii var. breweri native to California?
Yes. Cirsium douglasii var. breweri is native to California (recorded as native).
When does Cirsium douglasii var. breweri bloom?
Cirsium douglasii var. breweri blooms Jun-Sep.
Where in California does Cirsium douglasii var. breweri grow?
Cirsium douglasii var. breweri occurs in Humboldt, Butte, Lake, Lassen, Modoc, Nevada, Shasta, Siskiyou and other counties, at elevations of 1000-2200 m.
What plant family does Cirsium douglasii var. breweri belong to?
Cirsium douglasii var. breweri is in the Asteraceae family, genus Cirsium.
What habitat does Cirsium douglasii var. breweri grow in?
Cirsium douglasii var. breweri grows in Wet places, occasionally on serpentine.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.