Beer--I am wondering if what you call field mushroom is what I call meadow mushroom--Agaricus campestris? It is one of my favorites. However, I always do a spore print first since it so closely resembles several deadly poison amanitas that are common where I live and share the same fruiting season.

Re: puffballs--our rule of thumb--slice it cleanly down the middle. If there are no rudimentary gills, and if it is solid snowy white, it is safe. In our area we have to be particularly careful to distinquish between "gem-studded puffballs" and "earthstars." My husband and son love puffballs, but to me, their taste is cloyingly rich. I can eat a few--then I'm done with them.

Janie