ragwort

noun

any of various composite plants of the genus Senecio, as S. jacobaea, of the Old World, having yellow flowers and irregularly lobed leaves, or S. aureus (golden ragwort), of North America, also having yellow flowers.

noun

any of several plants of the genus Senecio, esp S. jacobaea of Europe, that have yellow daisy-like flowers: family Asteraceae (composites)See also groundsel (def. 1)

mid-15c., from ragged, in reference to the appearance of the leaves, + wort.