Cirsium sp.
Thistle, Thistle
(c) Jacek Pietruszewski, some rights reserved (CC BY), uploaded by Jacek Pietruszewski · licence
Family: Asteraceae · Type: Perennial · Variable; species dependent
Cirsium sp. (Thistle) is a non-native California perennial in the Asteraceae family.
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 sp. native to California?
No. Cirsium sp. is not native to California (recorded as variable; species dependent).
What plant family does Cirsium sp. belong to?
Cirsium sp. is in the Asteraceae family, genus Cirsium.
Related species
Other California species in the same genus, family, or bioregion.
- Cirsium undulatum — Wavyleaf thistle
- Cirsium vulgare — Bull thistle
- Cirsium andersonii — Anderson's thistle
- Cirsium andrewsii — Franciscan thistle
- Cirsium arizonicum — Arizona thistle
- Cirsium arizonicum var. arizonicum — Arizona thistle
- Cleomella arborea var. globosa — Bladderpod
- Constancea nevinii — Nevin's woolly sunflower
Sources: Jepson eFlora · CalPhotos
Last updated 2026-04-14
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.