280 days of Urbpandemonium #21
Firstly, cottonmanifesto took this picture. I saw and and was delighted, went to the compost heap myself and shot about a dozen pictures. Finally after disgusting myself with my collection of substandard photos, I decided to ask permission to use this one.
Cap and stem mushrooms aren't common in the New England springtime. It's only the heat of decomposition and the quick life-cycle of this fungus that allow these to thrive now. Many mushroom species emerge from a fungal mycelium that has been growing for months or even years. Coprinoid mushrooms are different, coming from a mycelium that grows quickly through an ephemeral food supply--dung, wet straw, compost, etc.
These are most likely Coprinopsis, one of the genera that was split from the formerly monolithic and easy-to-study Coprinus mushrooms. The mushrooms in these groups turn into a inky mush in order to spread their spores. Despite having that in common, several of these groups turned out not to be closely related to one another, requiring the shuffling of taxonomic names and the coining of the word "coprinoid" to refer to them all.
The scurfy scales on the tops of these mushrooms tempt me to identify them as Coprinopsis lagopus, the rabbit's foot inky. However that would be rash--microscopic examination of the spores would be a better way to try to speciate these.