Plants — part used: flower heads

6 plants whose part used is “flower heads”, each linking to its source.

• Bull thistle Cirsium vulgare
• Canada thistle Cirsium arvense
• Field thistle Cirsium discolor
• Nodding thistle Carduus nutans
• Plumeless thistle Carduus acanthoides
• Swamp thistle Cirsium muticum