Hello,

It is difficult to tell for sure without seeing a sample or specimen, because there are many characteristics that contribute to mushroom identification, and some of those characters are microscopic. This one probably has gills on the underside. From the picture, it looks like an Armillaria species, may or may not have a ring on the stalk and is present where the trunk of a tree had been. It may cause a heart rot or root rot of trees.  They tend to grow in clusters like this at the base or remains of trees such as oak and maple.  I recommend that you never eat anything you collect in the wild unless you have it identified in person by an expert. You could take a sample to your local Cooperative Extension or University office. Here is a web site from a colleague: http://www.mushroomexpert.com/.
Mushrooms are 90% water and you can rake over the lightly to break them up and the will dissipate. They may come up again in response to rains.

Thank you for contacting Cooperative Extension.

Nancy