Saw this today as I was working in the garden and figured I would share. After looking at some photos online, I think it is Agaricus Compestris. Let me know what you think in the comments.
I also submitted a picture to Project Noah, using their iPhone app, to see what people there have to say.
It could be, but very hard to tell just from one picture. The Agaricus’ are difficult to tell apart even if you have one in front of you while you are keying them out. They can also look deceptively like Amanitas, some of which are deadly. The best way to identify a mushroom is not by looking at pictures on line but using a dichotomous key. Two books with excellent keys are Mushrooms of Northeastern North America by Bessette, Bessette, and Fischer, and Mushrooms Demystified by David Arora. There are also a few good websites (Tom Volk’s page and Mycoweb among them listed on my mushroom production page at http://www.beginningfarmers.org/mushroom-production/. Just be careful, and don’t eat anything unless your 100% sure. There are a couple of really good wild Agarius, but I don’t get too excited about Agaricus simply because they are one of the few species you can buy in the store (as button mushrooms or portabella). Happy hunting!
Oh, no, I wouldn’t forage for mushrooms for myself. I enjoy life waaaaaay too much. (LAUGH)
I actually don’t like to eat them, so that makes it easier. I just noticed these popping up in the garden and figured I would share. I found a wonder fungo key online, but it seems that because these are just starting to grow, I couldn’t tell much about the underside. That said, it at least got me to the agaricus genus and then I used the images to narrow things down from there.