When looking through the 59 "Petunia" images at Acclaim Images.com this A Petunia Flower. was a favorite.
All of their pictures are hand picked, availiable in a number of formats, and you can even get custom prints and posters.

Description:
A Petunia Flower.
Stock Photograph: A Petunia flower.

Some related terms for more images:
floral,  purple,  pink,  botanical,  flower,  nature,  vertical,  horticulture,  beauty,  soft,  close up,  petunia,  bloom,  selective focus,  delicate,  plant,  steven james haggard,  grow,