Cirsium ochrocentrum var. ochrocentrum
Yellowspine thistle
(c) Michelle W. （鍾偉瑋）, some rights reserved (CC BY) · licence
Family: Asteraceae · Type: Perennial · Not Native
Cirsium ochrocentrum var. ochrocentrum (Yellowspine thistle) is a non-native California perennial in the Asteraceae family, recognized by runner roots, resinous phyllaries, and yellow spines diagnostic.
Yellowspine thistle is a naturalized perennial herb found in northern Channel Islands, Western Transverse Ranges, Peninsular Ranges, and Mojave Province in disturbed areas and fields at elevations below 1,700 meters. Flowering from April to July, this plant produces white to pale lavender or pink flowers in heads 2.5 to 4.5 centimeters wide, with distinctive spiny involucres. Growing with erect stems 25 to 100 centimeters tall, covered in white woolly tomentose, the plant develops from runner roots with generally simple lower stems and few branches toward the top. Its leaves are deeply lobed with rigidly spreading segments, featuring prominent spines 3 to 15 millimeters long, with proximal leaves up to 25 centimeters long and elliptic to oblanceolate in shape. The fruit is 6 to 9 millimeters long with a pappus 20 to 30 millimeters in length.
Identification and appearance
Key characters: 20 sympatric species; runner roots, resinous phyllaries, and yellow spines diagnostic
Habitat and range
Habitat: Disturbed areas, fields
Elevation: < 1700 m
Outside California: native to central United States
Bloom period
Cirsium ochrocentrum var. ochrocentrum blooms Apr-Jul.
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 ochrocentrum var. ochrocentrum native to California?
No. Cirsium ochrocentrum var. ochrocentrum is not native to California (recorded as not native).
When does Cirsium ochrocentrum var. ochrocentrum bloom?
Cirsium ochrocentrum var. ochrocentrum blooms Apr-Jul.
What plant family does Cirsium ochrocentrum var. ochrocentrum belong to?
Cirsium ochrocentrum var. ochrocentrum is in the Asteraceae family, genus Cirsium.
What habitat does Cirsium ochrocentrum var. ochrocentrum grow in?
Cirsium ochrocentrum var. ochrocentrum grows in Disturbed areas, fields.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.