Although online this painting is attributed to Georgia O'Keeffe, I have my doubts that it was actually painted by her. Compare to another image with the same name at http://curiator.com/art/georgia-okeeffe/black-and-purple-petunias-1. Compared to that image, this one looks pretty amateurish. Until I can find evidence that it was or was not painted by O'Keeffe I will leave it here.