SafePlants

Cirsium quercetorum - Alameda County Thistle

Cirsium quercetorum, commonly known as Alameda County thistle or Brownie thistle, is a species of thistle native to coastal California.

Considerations for Pets

• Thistles, in general, are known to have spines or prickles, which could pose a physical hazard to pets.

Taxonomy and Nomenclature

• Scientific Name: Cirsium quercetorum (A. Gray) Jeps.
• Common Names: Alameda County Thistle, Brownie Thistle
• Family: Asteraceae
• Synonyms: Cirsium quercetorum var. mendocinum

Distribution and Habitat

• Cirsium quercetorum is endemic to coastal California.
• Specific locations mentioned include Alameda County, Marin County (Point Reyes National Seashore), and coastal areas.
• It thrives in dry sites.

Morphological Characteristics and Growth Habits

• It is a forb/herb, meaning it's a non-woody plant that isn't a grass.
• It can be biennial or perennial.
• It typically grows to a size of 70-90cm.
• Thistles are known for their effusive flower heads, usually purple, rose or pink.

Ecological Role

• Cirsium vulgare (bull thistle, common thistle, or spear thistle) is listed as a noxious species. The text suggests the importance of weed management in Alameda County.
• The text mentions Artichoke thistle thrives on rangeland and can form an a wild, hard-to-control thistle form.

Interactions with Other Organisms

• The Mylitta Crescent (Phyciodes mylitta) caterpillar has been observed on thistles.

Further Information

• Dave's Garden: A community for sharing gardening tips and ideas.
• Discover Life: Provides information about the biology, natural history, ecology, identification, and distribution of Cirsium quercetorum.
• Garden Guides: Provides information on plant identification, uses, and gardening.