|Megacollybia rodmani and Pluteus cervinus|
Size might seem to be a difference from the photo above, but the described sizes of these two mushrooms completely overlap; I happened to pick an unusually long stemmed M. rodmani, and a very average P. cervinus. So size isn't the distinguishing feature.
Perhaps the key field feature is the attachment of the gills.
At home, they can be separated with a spore print. M. rodmani has a white spore print, while P. cervinus has a pinkish-brown spore print.
Are there other mushrooms these two could be confused with. Certainly! Especially if they are not growing directly on a rotten log, but on buried wood. M. rodmani, could be confused with species of Tricholoma or Collybia, while P. cervinus could be confused with species of Entoloma (and for both, many more I imagine).
Both are edible, but I've never tried either one. But honestly, I'm not 110 % certain of my identification, maybe 95 - 99% certain. But I'm pretty cautious, and I really don't need to eat mushrooms to thoroughly enjoy finding, observing, and identifying them (I really enjoy bird watching too, and I hardly ever eat any warblers, etc).