Georgia O'Keeffe is known for painting flowers that became emblems of female sexual liberation (and acting as a muse for her photographer husband, Alfred Stieglitz), but a 130-plus-piece show that just opened at the Whitney Museum establishes her as an innovator in abstract art. Outside of her landscapes, still lifes, and renderings of animal bones, she developed motifs (like swirls and wave forms) for rigorous and exuberant abstract work, inspired, but not limited, by the natural world. The following fifteen pieces include paintings that will surprise even some of her most devoted fans, and several of the charcoal drawings that convinced Stieglitz of her greatness. One of the many photographs he took of her closes out our slideshow.

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