Slightly off topic, but here is a list of things I have seen my omnivorous dogs eat or try to eat:
Dandelion flowers, little white daisy-like flowers that grow in the lawn here, pansies, grass -- any kind they see, I think, poison oak buds (I discourage this) rhododendron stems (I discourage this), fern fiddleheads, blackberries, salal berries, carrots, apples, lettuce, deer shit, mud -- the boy eats a lot of mud.
I offered them doug fir buds, but they declined.

Disclaimer: I do feed them the best mass produced dog food I can currently afford to, so especially the mud makes me think there is some mineral missing in it. They are puppy mill survivors, were adults when rescued. I think that has left them open to ANY food possibilities.