These little mushrooms popped up in one of our treebeds earlier this week, and will likely be gone in the next week or so, after they’ve finished releasing their windblown spores. But their web of mycelium will remain underground, where they help to break down dead plant matter, exchanging water and nutrients with plant roots in vast networks of underground fibers extending under the sidewalk.
I don’t know enough about mushrooms to be sure, but I believe these are examples of “Shaggy Parasol” a type of mushroom known as chlorophyllum, and I’m glad I caught sight of them during their brief visit aboveground.