Sunflower

Sunflowers were a plant species unique to Earth. (AUDIO: Caerdroia)

Amy Pond gave many sunflowers to Vincent van Gogh as a gift for saving her from the Krafayis. (TV: Vincent and the Doctor)

Face-Painter once painted a sunflower on the Second Doctor's face. (PROSE: Face-Painter)

The Tenth Doctor once reprogrammed a want conduit to only work when the user thought about sunflowers and ball bearings. (PROSE: The Slitheen Excursion)