Cirsium brevistylum
Clustered thistle
(c) Garth Harwood, some rights reserved (CC BY), uploaded by Garth Harwood · licence
Family: Asteraceae · Type: Herb · Native
Cirsium brevistylum (Clustered thistle) is a native California herb in the Asteraceae family, recognized by sessile heads with knob-tipped corolla lobes and equal phyllaries are key.
Clustered thistle is a California native perennial herb found in northwestern, central western, southern coastal, and northern Channel Islands bioregions in moist places at elevations below 500 meters. Flowering from March to August, this plant produces white to purple flowers in heads 2.5 to 3.5 centimeters wide, with needle-like phyllary tips and a loosely cobwebby appearance. Growing 30 to 350 centimeters tall with a single generally branched stem that is jointed-hairy and sometimes cobwebby, particularly near the flower heads. Its leaves are gray-tomentose underneath, with proximal leaves 15 to 25 centimeters long, shallowly lobed and dentate, featuring spines 3 to 7 millimeters long. The fruit is 3 to 4.5 millimeters long with a pappus 10 to 22 millimeters in length.
Identification and appearance
Key characters: 35 sympatric species; sessile heads with knob-tipped corolla lobes and equal phyllaries are key
Habitat and range
Habitat: Moist places
Elevation: < 500 m
Outside California: to British Columbia, Montana
Bloom period
Cirsium brevistylum blooms Mar-Aug.
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 brevistylum native to California?
Yes. Cirsium brevistylum is native to California (recorded as native).
When does Cirsium brevistylum bloom?
Cirsium brevistylum blooms Mar-Aug.
What plant family does Cirsium brevistylum belong to?
Cirsium brevistylum is in the Asteraceae family, genus Cirsium.
What habitat does Cirsium brevistylum grow in?
Cirsium brevistylum grows in Moist places.
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.