SafePlants

Thistle Overview

This page provides information about various thistles, drawing from mentions across different contexts, including botanical surveys, weed management initiatives in Wyoming, and even local businesses named "The Thistle."

Considerations for Pets and Children

• Several species of thistle possess sharp spines or prickles, presenting a potential hazard.
• The text mentions "arachnoid-tomentose" stems, suggesting a hairy or woolly texture that might be irritating to some individuals.

Scientific and Common Names

• Scientific Name: Hyoscyamus niger L. is mentioned (Black Henbane), but the text primarily focuses on thistles belonging to the Cirsium and Carduus genera.
• Common Names: Thistle, Canada Thistle, Bull Thistle, Common Thistle, Spear Thistle, Musk Thistle, Scotch Thistle, Plumeless Thistle, Wyoming Thistle, Ownbey's Thistle, St. Barnaby's Thistle.

Taxonomy and Nomenclature

• Family: Asteraceae (specifically mentioned for Cirsium ownbeyi)
• Synonyms and Alternative Names:
  • Carduus acanthoides L. (Plumeless Thistle)
  • Cirsium arvense (L.) Scop. (Canadian Thistle)

Distribution and Habitat

• The primary geographical focus is Wyoming, USA, with mentions of specific locations like Cody and Uinta County.
• Canada Thistle, despite its name, is native to Europe and Western Asia and has been introduced in the 1600s. It's found in every county in Wyoming.
• Milk Thistle, originally from Europe, now grows in the United States.

Ecological Role

• Several thistles are classified as noxious weeds, including Canada Thistle, Musk Thistle, Scotch Thistle, and Plumeless Thistle.
• Russian Thistle is described as an invasive plant that often becomes a "tumbling tumbleweed."
• The text mentions a grasshopper that plays a beneficial role when inhabiting patches of Russian thistle.

Morphological Characteristics

• Thistles are described as taprooted perennials with erect or ascending stems.
• Some stems are "arachnoid-tomentose," meaning they have a cobweb-like, hairy covering.
• Wyoming Thistle is identified by bracts collectively less than 0.8 inches high, lacking rhizomes, and leaves white.

Interactions with Other Organisms

• The text references studies conducted to evaluate the effect of foliar phosphorus levels on the acceptance of host plants by thistle-feeding insects.
• A grasshopper plays a beneficial role when populations inhabit patches of kochia, Russian thistle.

Resources and Further Information

• Wyoming Weed Watchlist Field Guide
• Wyoming Department of Agriculture
• Wyoming Natural Diversity Database
• USWildflowers Database State List for Wyoming
• US Fish & Wildlife
• Discover Life (for information on Cirsium pulcherrimum)
• Wyoming Agricultural Experiment Station Bulletin 912
• Weeds of the West. Jackson, WY: Univ. Wyoming and Western Society of Weed Science.

Quirky Facts

• "The Thistle" is the name of a store in Cody, Wyoming, specializing in unique gifts.
• "The Thistle & Shamrock" is one of NPR’s longest-running and most popular music offerings.
• In 1895 Russian Thistle found the scorn of not only Wyoming, but many of the Midwestern states.