[Members of the Sunflower Family with
Discoid Flower Heads East of the Cascade Mountains of Oregon and Washington]
Cottonthistles East of the Cascade Mountains of Oregon and Washington
The Genus Onopordum
Scotch Thistle: Onopordum acanthium
Cottonthistle, Cotton Thistle, Scotch Cottonthistle, Scotch Thistle, Scots Thistle: Onopordum acanthium (Synonym: Onopordum acanthium ssp. acanthium) -
Bull Cottonthistle, Taurian Thistle: Onopordum tauricum -
Paul Slichter