Urospermum picroides
Bristly tail seed
(c) Elizabete Marchante, some rights reserved (CC BY), uploaded by Elizabete Marchante · licence
Family: Asteraceae · Type: Herb · Not Native
Urospermum picroides (Bristly tail seed) is a non-native California herb in the Asteraceae family, recognized by European introduction, only Urospermum species naturalized in California.
Bristly tail seed is a naturalized perennial found in northern Sierra Nevada foothills, northern Central Coast, San Francisco Bay Area, southern California, and southern Transverse Ranges in disturbed places at elevations below 400 meters. Flowering from April to July, this plant produces yellow flowers in heads 1.3 to 2.2 centimeters long with widely lanceolate phyllaries. Growing with stems 10 to 40 centimeters tall, covered in long hairs and slender spine-like bristles, it has an erect and somewhat branching habit. Its lower leaves taper to the base while upper leaves are sessile and clasping, with toothed or lobed blades showing variation along the stem. The fruit is 11 to 14 millimeters long with a beak longer than its body.
Identification and appearance
Key characters: European introduction, only Urospermum species naturalized in California
Habitat and range
Habitat: Uncommon. Disturbed places
Elevation: < 400 m
Outside California: native to Europe
Bloom period
Urospermum picroides blooms Apr-Jul.
How to tell it apart
vs Sonchus: Urospermum has wide basally-fused bracts; Sonchus has multiple rows of overlapping narrow bracts; vs Taraxacum: Urospermum has leafy stems; dandelion has only basal leaves with leafless flower stalks; vs Helminthotheca: Urospermum has one series of fused bracts; Helminthotheca has two distinct free bract series; vs Hypochaeris: Urospermum has leaves along flowering stems; Hypochaeris has leafless or nearly leafless stems; vs Carduus: Urospermum has strap-shaped ray flowers only; Carduus has tubular disk flowers and spiny bracts
Frequently asked questions
Is Urospermum picroides native to California?
No. Urospermum picroides is not native to California (recorded as not native).
When does Urospermum picroides bloom?
Urospermum picroides blooms Apr-Jul.
What plant family does Urospermum picroides belong to?
Urospermum picroides is in the Asteraceae family, genus Urospermum.
What habitat does Urospermum picroides grow in?
Urospermum picroides grows in Uncommon. Disturbed places.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · 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.