Silybum sp.
Milk thistle, Milk Thistle
Family: Asteraceae · Type: Annual · Not Native
Silybum sp. (Milk thistle) is a non-native California annual in the Asteraceae family.
How to tell it apart
vs Carduus: Silybum has white-marbled leaves and smooth stems; Carduus lacks white marbling and has continuous spiny wings down stems.; vs Cirsium: Silybum leaves have bright white vein marbling; Cirsium leaves are plain green without white markings.; vs Centaurea: Silybum has large glossy leaves with white marbling; Centaurea has smaller, non-glossy leaves without white veins.; vs Cynara: Silybum has white-marbled leaves and heads on long stalks; Cynara lacks marbling and has massive short-stalked heads.; vs Sonchus: Silybum has spiny thistle heads; Sonchus has dandelion-like yellow flowers and hollow stems with milky sap.
Frequently asked questions
Is Silybum sp. native to California?
No. Silybum sp. is not native to California (recorded as not native).
What plant family does Silybum sp. belong to?
Silybum sp. is in the Asteraceae family, genus Silybum.
Related species
Other California species in the same genus, family, or bioregion.
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.