As I've pointed out before, you don't have to go all the way to Mt. Tam to find the wonders of nature. While talking through Golden Gate Park I stumbled upon a field of Fluted Black Helvella mushrooms. These oddly shaped fungi (at first I thought they were dirt clods) have what is often called a saddle-shaped cap (although it usually looks more crumpled) and a stalk that looks like pulled taffy. They are distant relatives of the prized Morel mushrooms.
I have seen these mushrooms in the park before and on Mt. Tamalpais, but I had never seen 50 of them in a group like this, most likely all part of one large set of mycelium, exchanging nutrients with a nearby tree.