identify these mushrooms

My yard is exploding with mushrooms.  Mostly of the same type....


In my lawn/pasture


In my flower beds

These pictures show the various stages of the same mushroom. 
Does anyone know the type and can we eat them?

Thanks,

~Jami

From your photos they look very like St George mushrooms BUT be very careful they could also be the deadly Death Cap (Amanita phalloides) or any of hundreds of white species of mushroom

You should show them to an expert who will show you how to do a spore test to find out what they are and whether or not they're edible.

Amanita
http://en.wikipedia.org/wiki/Amanita_phalloides

St Georges
http://www.celtnet.org.uk/recipes/ancient/wild-food-entry.php?term=St%20Georges%20Mushroom

http://www.rogersmushrooms.com/gallery/DisplayBlock~bid~5697.asp

Thank you so much for the reply and links - great info.

I see what you mean about how they can be confused.

~Jami

that's biodiversity in your yard!
You are right, it is very very important to seek advice before eating any kind of mushroom, Amanita palloides for example can kill you.
I am not an expert, but please allow me to guess. Your two photos give only impressions, incomplete information for identification, so the best is only to make big guesses from which you may start your research : the white ones beside the flower pothmost probably are from the family Agaricaceae; the brown behind probably are from the family Russulaceae; the white ones on your pasture probably are also from the family Agaricaceae, perhaps Agaricus campestris (also) because they have sprouted from your lawn.
Happy mushrooming!

I wouldn't go out eating any of those without a 100% positive identification.  If you are really interested in finding out, one step that will help immensely with identification is taking a spore print.  This can be done by cutting off a cap and leaving it face down on a piece of paper and covered for half a day or more with a glass to keep the cap from dehydrating (though you probably want to put a corner of the glass on a towel or something to avoid the cap molding).  The spores will all fall from the gills onto the paper and their color is often a key identifying feature for mushrooms.