Sun where you find it

I was at an herb workshop this weekend and someone asked whether there was any medicinal value in buttercups.  The answer was no, but I take issue with that answer.  I think just looking at the near blinding brightness of their petals has healing power similar to the sun.  Especially during gray springs such as this one.

I remember in elementary school we used to play some kind of game that involved twirling a buttercup under our chins.  I can't remember why, but part of the reason was to see the way the bright yellow was reflected on our skin. 

 I can't think of a brighter flower, like a little light box.