This delicate looking little lovely is commonly called the'Black-footed Marasmius'. It is plentiful these wet weeks of summer, growing on twigs (as in the photo above) as well as on leaf-litter. Notice the white umbrella-like pleated cap, its white gills, and the faintly hairy black stipe. Like other species of Marasmius, these mushrooms are tough! They can appear to shrivel to nothing in dry weather, but give them a bit of rain and they are revived!