Corn Sow Thistle, Field Sowthistle, Field Sow Thistle, Field Sow-thistle, Perennial Sow Thistle: Sonchus arvensis var. arvensis (Synonym: Sonchus arvensis var. shumovichii) -
Prickly Sow Thistle, Prickly Sow-thistle, Spiny Sowthistle, Spiny Sow-thistle, Spiny-leaf Sow-thistle: Sonchus asper (Synonyms: Sonchus asper ssp. asper, Sonchus asper ssp. glaucescens, Sonchus nymanii, Sonchus oleraceus var. asper) -
Annual Sow Thistle, Common Sowthistle, Common Sow Thistle, Common Sow-thistle: Sonchus oleraceus -