Purple leaves

Why are plant leaves green? Well for the most part. There are obviously some exceptions, such as those above.
Leaves look green because they absorb red and blue light, leaving green to be reflected. Now if they absorbed all the light, including green, they would have more energy to play with. The suns output peaks in the yellow, so they're missing out in several ways. A black leaf would be most efficient.

Even the leaves above that reflect less light don't do much with the extra they absorb. Those with dark or black leaves have a absorbing layer mostly to stop harmful rays from messing with the leaf internals. They don't derive any extra efficiency in photosynthesis from it.

They're missing a trick, and no one quite knows why!