Which flowering plant is related to edible vegetables, Petunias or Rudbeckia?
Petunia: Petunia is genus of 35 species of flowering plants of South American origin, closely related to tobacco, cape gooseberries, tomatoes, deadly nightshades, potatoes and chili peppers in the same family, Solanaceae. Rudbeckia:  The species are commonly called coneflowers and black-eyed-susans; all are native to North America and many species are cultivated in gardens for their showy yellow or gold flower heads.
Petunia