Carthamus leucocaulos
Whitestem distaff thistle
(c) Eleftherios Katsillis, some rights reserved (CC BY) · licence
Family: Asteraceae · Type: Herb · Not Native
Carthamus leucocaulos (Whitestem distaff thistle) is a non-native California herb in the Asteraceae family, recognized by but extirpated; key features are shiny white stems and pale purple flowers.
Whitestem distaff thistle is a naturalized annual found in southern North Coast Ranges grasslands, apparently extirpated and occurring at elevations below 200 meters. Flowering from July to September, this plant produces pale purple flowers in heads 10 to 13 millimeters wide with prominently spiny phyllary tips. Growing 30 to 100 centimeters tall with generally shiny white stems that become nearly hairless, the plant develops a distinctive appearance. Its cauline leaves are deeply lobed and very spiny, creating a formidable texture along the stem. The fruit is small, brown, and 3 to 5 millimeters long with a pappus 5 to 7 millimeters in length.
Identification and appearance
Key characters: 3 sympatric species but extirpated; key features are shiny white stems and pale purple flowers
Habitat and range
Habitat: Grassland
Elevation: < 200 m
Outside California: native to Mediterranean
Bloom period
Carthamus leucocaulos blooms Jul-Sep.
How to tell it apart
vs Centaurea: Carthamus has spine-tipped leaf lobes and yellow to orange flowers; Centaurea has spine-tipped bracts but purple to pink flowers.; vs Cirsium: Carthamus has four-angled seeds with scale-like pappus; Cirsium has rounded seeds with feathery bristle pappus.; vs Carduus: Carthamus has yellow to orange flowers; Carduus has purple to pink flowers with feathery pappus bristles.; vs Scolymus: Carthamus has many-flowered heads with outer spiny bracts; Scolymus has large yellow ray flowers with spiny-winged stems.; vs Silybum: Carthamus has spine-tipped leaf lobes; Silybum has spine-edged leaves with distinctive white marbling or veining.
Frequently asked questions
Is Carthamus leucocaulos native to California?
No. Carthamus leucocaulos is not native to California (recorded as not native).
When does Carthamus leucocaulos bloom?
Carthamus leucocaulos blooms Jul-Sep.
What plant family does Carthamus leucocaulos belong to?
Carthamus leucocaulos is in the Asteraceae family, genus Carthamus.
What habitat does Carthamus leucocaulos grow in?
Carthamus leucocaulos grows in Grassland.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · 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.