I found this mushroom at a local park growing on a tree. As you can see in the photo, there were lots growing together. This mushroom has gills, and its cap is convex. The cap had a light brown colour with some dark spots at the center. The cap margin is even and its surface is smooth. The gills are adnate, the stem appears central, flexuous and longitudinally striated. I think this mushroom belongs to Hypholoma based on its gill shape, cap features, and ability to grow on trees.
