The term 'Yellow Wildflower' can be broken down into two crossword solutions: BUTTERCUP (9 letters) and PRIMROSE (8 letters). Buttercups are a genus of flowering plants in the family Ranunculaceae, with bright yellow flowers that have five petals. Primroses are a genus of flowering plants in the family Primulaceae, with yellow flowers that have five petals. Both of these wildflowers are popularly found in gardens and meadows throughout Europe and North America.