You know, I said a little while ago that I should make a special website or other media project that collects all the mushrooms commonly found in human-impacted and human created ecosystems. Something like http://urbanmushrooms.com/
which, as it turns out, already exists. It's not perfect (found some obsolete synonyms in use there) but it is exactly what I was thinking of doing. Not that I can't do the same thing in my own style, but I thought you should know it's there.
So, speaking of which, here is a mushroom found only indoors--at least in temperate zones. This is a tropical species, Leucocoprinus birnbaumii
which has found its way into the highly fragmented yet consistent ecosystem of greenhouses and house plants. This fruiting appeared in one of the planters in the Tropical Forest exhibit at Franklin Park Zoo (in a place not visible to the public nor accessible by the animals, in the giant anteater exhibit). A zookeeper friend (perhaps one seen here earlier, pointing her lips at a beetle grub) brought it to my attention, as I am becoming known as "the mushroom guy" around work.
As luck would have it, I had seen photos of the mushroom online the week before--a gardener found it in his potted pepper plant and was posting it concerned that it would harm his peppers or transfers poisons to them. (By the way, the answer is no to both. Mushrooms coming from the soil near a plant are almost always beneficial or neutral to the plant--parasites usually grow directly from the visible plant tissue. Poisonous mushrooms don't imbue their neighbors with poisonous essence--if anything, they are more likely to remove poisons from the nearby soil.)
This fascinating adaptation to the great indoors is paralleled by many small tropical animal species as well as tropical microbes. There are studies being done as we speak comparing the indoor wildlife of households in different parts of the world. I look forward to seeing the results of these studies--what do we all share, what's unique to one place or another. This mushroom is one of only two mushrooms I am aware of that is primarily found indoors, at least through much of its range.
A freshly emerged Leucocoprinus
button. Common names for this mushroom boil down to some combination of "yellow," "potted plant," and "parasol."
This mushroom is dainty and beautiful, and resembles mushrooms in the Coprinus
group, most of which are edible. This species is not
edible to humans, causing some gastric distress. Its edibility to anteaters is not known to be, but fortunately they were growing out of his reach.