Which mushrooms are poisonous to dogs?

I have lawn mushrooms in my yard. I've never seem them there before, but it has been rainy the last few days and my yard does have a habit of flooding. Anyway my dog ate one, and rather than risk anything we brought her to the vet to get her stomach pumped. the Vet was not sure whether or not they are poisonous. My dog wants to run all over my fenced in yard but we're afraid of letting her off the leash because we don't want her to eat one. Anyone have any advice? Thank you.