Spinellus on a Mycena - Hawk Mountain, PA, Mushroom walk with Lee Schisler, Jr. (Sep 9, 2006)

Paraphrased from other sources on the web:

This Mycena has Spinellus growing on it. Spinellus is a member of the bread mold family, however, it doesn't grow on bread, it prefers mushrooms, and it prefers the Mycena.

The Spinellus grows inside the cap of the Mycena until it decides it's ready to 'grow'. Spinellus is a terrific parasite as it lets it's host (the Mycena) age and release it's spores before it kills it and turns the poor mushroom into a wet messy puddle. This is a smart thing to do as Spinellus surely wants to insure having more hosts next year to grow on.

Spinellus is characterized by it's long stalks (sporangiophores). At the end of the sporangiophores are tiny little balls (sporangia) that contain the spores of the Spinellus. In the picture you can see the fine 'hairs' (sporangiophores) and the little sporangia at the ends that look like little black dots.

If you'd like to try growing your own Spinellus and you don't happen to have a Mycena handy, you might want to take a peach and set it outside in September. Spinellus loves a ripe, juicy peach.