You must be thinking of Georgia O'Keefe (b.1887) whose flower paintings have a definite sexual quality. She studied at the Chicago Art Institute, the Art Student's League (with William Merritt Chase), the University of Virginia and Columbia. Her first one-woman show was at Gallery 291 in NYC which was run by the photographer Alfred Stieglitz whom she later married. Following his death in the late 1940's she moved to New Mexico where she created her best known works of flowers, skulls and landscapes.