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Taxon  Report  
Onopordum acanthium  L.
Scotch cottonthistle
Onopordum acanthium is a perennial herb that is not native to California.
Cal-IPC rating: high
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Observation Search
~2332 records in California
redone or more occurrences
within a 7.5-minute quadrangle
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Bloom Period
Subspecies and Varieties:
Genus: Onopordum
Family: Asteraceae  
Category: angiosperm  
PLANTS group:Dicot
Jepson eFlora section: eudicot

Name Status:
Accepted by PLANTS

Information about  Onopordum acanthium from other sources
USDA PLANTS Profile (ONAC)

Photos on Calflora

Photos on CalPhotos

Google Images

Photos on iNaturalist

[Cal-IPC] Invasive: Onopordum acanthium (Scotch thistle) is a biennial or short-lived perennial (family Asteraceae) which is primarily found in the northeastern regions of California. Severe infestations can form tall, dense, impenetrable stands, especially in fertile soils. Onopordum acanthium reproduces only by seeds, which can germinate year round, and it is drought resistant. Infestations can reduce forage and impede movement for livestock and wildlife. Cal-IPC Rating: High (contributed by Mary Ann Machi)

[Wikipedia] Europe & Western Asia native: Onopordum acanthium (cotton thistle, Scotch (or Scottish) thistle) is a flowering plant in the family Asteraceae. It is native to Europe and Western Asia from the Iberian Peninsula east to Kazakhstan, and north to central Scandinavia, and widely naturalised elsewhere,[1][2][3] with especially large populations present in the United States and Australia. It is a vigorous biennial plant with coarse, spiny leaves and conspicuous spiny-winged stems (contributed by Mary Ann Machi)


Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals. [web application]. 2024. Berkeley, California: The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 05/25/2024).