Take one of these shrooms cut the stem off. Lay half of the cap gills down on a piece of white paper and black construction paper... Your shrooms appear to be Honey Fungus. We need to take a look at the stem to see if there is a ring around the stem under the cap... Honey Fungus will transpose a white spore print on the black test paper... If brown appears on the white side of the paper it sure isn't honey fungus.. Now I don't want you to eat these things but I have a feeling it's Honey Fungus.. Also are they on wood.. See there are many variables you have to look at before you can determind if they are Honey Fungus.. HF grows on wood.
If it is honey fungus your Holly Tree is doomed...It's probably going to die sometime out into the future years.. Honey Fungus the shroom is edible but the other parts of this shroom under the ground kills trees..