Cirsium ciliolatum
Ashland thistle
(c) Corey Brooke, some rights reserved (CC BY) · licence
Family: Asteraceae · Type: Herb · Native
Conservation status: CNPS 2B.1
Cirsium ciliolatum (Ashland thistle) is a native California herb in the Asteraceae family, recognized by northern Klamath range, white-tomentose herbage, and nearly spineless basal leaves.
Ashland thistle is a rare (CNPS 2B.1) California native perennial found in northern Klamath Ranges in grassy areas and open woodland at elevations around 800 meters. Flowering from June to July, this plant produces dull white to lavender flowers in heads 1.5 to 3 centimeters wide, arranged in small flat-topped clusters. Growing 60 to 200 centimeters tall with mostly simple stems that are covered in white cobwebby or dense tomentose hairs, it develops ascending branches. Its leaves vary from entire to deeply lobed, with proximal leaves wing-petioled and upper leaves gradually reduced, appearing green on top and whitish underneath with spines 1 to 6 millimeters long. The fruit is 3.5 to 7 millimeters long with a pappus 15 to 20 millimeters in length.
Identification and appearance
Key characters: 17 sympatric species; northern Klamath range, white-tomentose herbage, and nearly spineless basal leaves
Habitat and range
Habitat: Grassy areas, open woodland
Elevation: +- 800 m.
Outside California: southern Oregon
Bloom period
Cirsium ciliolatum blooms Jun-Jul.
Conservation status
CNPS 2B.1
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 ciliolatum native to California?
Yes. Cirsium ciliolatum is native to California (recorded as native).
When does Cirsium ciliolatum bloom?
Cirsium ciliolatum blooms Jun-Jul.
What plant family does Cirsium ciliolatum belong to?
Cirsium ciliolatum is in the Asteraceae family, genus Cirsium.
Is Cirsium ciliolatum rare or endangered?
Cirsium ciliolatum carries California Rare Plant Rank 2B.1, state rank S1.
What habitat does Cirsium ciliolatum grow in?
Cirsium ciliolatum grows in Grassy areas, open woodland.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos · CDFW CNDDB
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.