I found these under some dead bark at the base of an old dead fallen oak tree. They were in a tight cluster and were bright yellow. The pictures don't do them justice, though, because it was getting dark when the photos were taken. The spore print is rusty orange, the gills are attached to the stem, and they stain blueish green. The gills are a slightly lighter yellow or even pale yellow, compared to the cap. They smell pleasant, but also as if the would taste bitter if eaten. If I could get any assistance in identifying these, it would be greatly appreciated.