Mystery Mushrooms in Back Yard

Some photos of polyspore mushrooms growing in our backyard in a spot where we had a large pine tree removed and the stump ground. I took a stab at identifying the mushroom from photos I found online but while it looks a bit like meripilius giganteus it clearly isn't one.



Whatever it is it's quite large. Several of the fruiting bodies are more than a foot across.



The main thing that convinces me that this is not meripilius giganteus is that several sources have said that giganteus (which of all the photos I found on line it most resembles) makes a white spore print, while my mushrooms sit in a dusty pool of red-brown cinnamon-colored spores.



Here's a closeup of some grass that has been covered with the obviously not-at-all white spores.



I started to clear away the grass to get a better photo but was fascinated to find that the musrooms had grown around the grass instead of pushing it aside. Here is a stem of grass growing through the middle of the mushroom.



When these mushrooms first emerge they look rather like an over-cooked fried egg -- a white, plate-shaped cap with a egg-yolk-yellow center and a brownish rim around the edges. As they mature the center color darkens and spreads and the single plate-shape grows quite large. Once it gets about 10 inches in diameter other plates start to grow on top but they lay quite flat (compared to other photos I have seen of similar mushrooms). The younger growths have a bit of a spiral shape and are rather pretty, I think.



Here's a shot from another angle with Jaxon getting into the photo.



One last photo from yet another angle. As I mentioned above, the area where the mushrooms are growing is the spot where we had a large (24" diameter) pine tree removed (after watching similar trees squashing houses in our neighborhood like bugs during wind storms.) The mushrooms are obviously growing on the decomposing roots of the tree and, I think that the part of the mushroom that shows above ground is a small part of a larger, mostly underground organism.



I am fairly sure that several of my friends developed an interest in mushrooms during their wild college days. If you are one of them and you remember anything about mushrooms -- or, for that matter, much about college -- and you have any notion of what sort of mushroom I have here, do let me know.