Butterweeds, Groundsels and Ragworts: The Genus Packera west of the Cascade Mountains
Butterweeds, Groundsels and Ragworts with discoid flower heads (lacking ray flowers)
Silver Ragwort: Jacobaea maritima - Introduced to Puget sound bluffs from the Mediterranean.
Stinking Willie, Tansy Ragwort: Jacobaea vulgaris (Synonym: Senecio jacobaea) -
Dwarf Mountain Groundsel, Dwarf Mountain Ragwort: Senecio fremontii var. fremontii -
Stout Meadow Groundsel, Sweet Marsh Butterweed: Senecio hydrophiloides (Synonyms: Senecio foetidus, Senecio foetidus var. foetidus, Senecio foetidus var. hydrophiloides, Senecio oreganus) - Rays few in number. Flower heads may appear rayless.
Alkali Marsh Butterweed, Alkali Marsh Ragwort, Water Groundsel, Water Ragwort: Senecio hydrophilus (Synonym: Senecio hydrophilus var. pacifica) - Rays few in number. Flower heads may appear rayless.
Columbia Ragwort, Lambstongue, Lambstongue Groundsel, Lambs-tongue Groundsel, One-stemmed Butterweed, Tall Western Groundsel: Senecio integerrimus var. exaltatus (Synonyms: Senecio integerrimus var. vaseyi, Senecio vaseyi) -
Bigheaded Groundsel: Senecio integerrimus var. major -
Western Groundsel, White Western Groundsel: Senecio integerrimus var. ochroleucus (Synonym: Senecio exaltatus ssp. ochraceus) -
Black-tipped Groundsel, Small Blacktip Ragwort: Senecio lugens (Synonym: Senecio integerrimus var. lugens) -
Olympic Mountain Ragwort: Senecio neowebsteri -
Wood Groundsel, Woodland Groundsel, Woodland Ragwort: Senecio sylvaticus -
Arrowleaf Groundsel, Arrowleaf Ragwort: Senecio triangularis (Synonyms: Senecio gibbonsii, Senecio triangularis var. angustifolius, Senecio triangularis var. triangularis) -
Sticky Groundsel, Sticky Ragwort: Senecio viscosus -