Calflora, a 501c3 non-profit
Distribution by County   1504    
Carduus pycnocephalus  L.
Italian thistle
Carduus pycnocephalus is an annual herb that is not native to California.
Cal-IPC rating: moderate
Record Count by County

Alameda: 365 Los Angeles: 618 San Benito: 197 Sonoma: 404
Amador: 29 Madera: 103 San Bernardino: 47 Stanislaus: 41
Butte: 66 Marin: 1122 San Diego: 884 Sutter: 16
Calaveras: 88 Mariposa: 750 San Francisco: 208 Tehama: 19
Colusa: 24 Mendocino: 70 San Joaquin: 365 Trinity: 22
Contra Costa: 375 Merced: 37 San Luis Obispo: 131 Tulare: 611
Del Norte: 1 Monterey: 275 San Mateo: 741 Tuolumne: 1004
El Dorado: 70 Napa: 68 Santa Barbara: 151 Ventura: 238
Fresno: 99 Nevada: 78 Santa Clara: 851 Yolo: 47
Glenn: 12 Orange: 1181 Santa Cruz: 331 Yuba: 105
Humboldt: 35 Placer: 39 Shasta: 18
Kern: 145 Riverside: 57 Siskiyou: 7
Lake: 25 Sacramento: 422 Solano: 102

Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria. [web application]. 2025. Berkeley, California: The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 01/31/2025).