Petunia Part is a term used to describe the four parts of a petunia flower. The first part is the SEPAL, which is a green leaf-like structure that protects the flower bud before it blooms. The second part is the PETAL, which is the colorful and fragrant part of the flower that attracts pollinators. The third part is the STALK, which is the STEM that supports the flower. The fourth part is the STEM, which is the main body of the flower that connects the other parts.