Nope. They're something else.

the usual caveat with shroom ID is that its really hard to ID on pix alone ... e.g. there are too many look alikes .... so if you are looking for things to eat.. you should find a local expert or shroom hunting club .... if you are just searching for ID ... for the sake of knowledge ... close enough .... btw ... i wouldnt argue with either of those who appear to have offered the same ID ... so in this case .... who rah .... ken

If you read long enough about Armillaria just about the only things that really are resistant are turf grass and yews. With magnolias being a classic target genus - look at just about any book about growing them and Armillaria attacks are always discussed. With the worst, most textbook example I have seen in person of sheets of bark falling off a trunk to reveal honey fungus beneath being a magnolia tree. Grinding of infested stumps has been recommended, as though it is thought fragmenting the remains of the previous host would somehow louse things up for the fungus. Otherwise one can actually watch for rhizomorphs on subsequent plantings and pull them off. This keeps their trunks from being killed anyway - there actually seems to be a thing where the fungus is trying to topple infested trees in order to make their trunks more accessible. Consistent with this when I had the entire top of a big-leaf magnolia die suddenly one recent year, looked at it afterward to see a clearly recognizable honey fungus attack it had only gone mere inches up the trunk.

its decomposing your mulch ... regardless of what it is ... shrooms are fungus.. arent they .... lol ... since they dont have roots.. they really dont compete for water with the other plants ... so nothing need be done ... i tend to think of them.. as a free garden gift of ma nature.. and enjoy them for such.. rather than think i need to eradicate them ... i only eat purchased mushrooms.. so i have no opinion on all that ... ken