eyespot

noun4

1. •
   An eye-like marking on the tail of a peacock or the wing of a butterfly.
2. •
   Any of various primitive light-sensitive organs or regions in many diverse organisms.

   • The eyespot is a complex sandwich of membranes with rows of granules that contain around 200 different proteins, including the same rhodopsins found in the retina of our own eye. — 2011
3. •
   A coloured spot in a motile gamete or spore, which is sensitive to light.
4. •
   Any of a group of fungal infections of grasses that are characterized by oval spots; strawbreaker.