butterweed

[ buht-er-weed ]
/ ˈbʌt ərˌwid /

noun

any wild plant having conspicuously yellow flowers or leaves.
the horseweed.
a ragwort (Senecio jacobaea) or groundsel (S. vulgaris), both having yellow ray flowers.

Origin of butterweed

First recorded in 1885–90; butter + weed1