Mica Caps

Welcome back to Mushroom Monday, your weekly look at some of PEI’s fascinating fungi. Little brown mushrooms can be tricky to identify, but today’s species has features that help it stand out: meet Mica Caps (Coprinellus micaceus).

Mica Caps are part of the Inky Cap group of mushrooms, just like the Shaggy Manes (Coprinus comatus) I’ve posted about before. Although these two species share a similar approach to spore dispersal, they’re not closely related. As we’ve seen in this series, mushrooms are often grouped by physical similarities rather than taxonomy.

Like most other Inky Caps, Mica Caps dissolve into black goo as they mature (inset photo). Called deliquescence, this process is part of the mushroom’s reproductive strategy: that goo is full of spores that help the fungus spread. This inky habit is shared by dozens of species of mushrooms, and so it alone isn’t enough to identify Mica Caps.  

When they first appear, Mica Caps are oval- or bell-shaped, with tan-coloured caps that are often darker towards the centre (main photo). Those caps have fine grooves running from the margins almost to the centre, and – if you look closely – you may see the tiny, shiny (mica-like) granules that give this mushroom its common name (main photo), though these can be washed away by rain and so aren’t always present. Under the cap, Mica Caps have delicate, hollow white stems; gills are light at first but quickly darken through brown to black.

Mica Caps are among the most frequently-recorded fungi in North America and have been found in every Canadian province and territory (except Nunuvut) and every US State, as well as Central and South America, Europe, Asia, Africa, and Australia. Here on PEI, they can commonly be found growing in large, crowed groups around tree stumps or on buried wood.

Mica Caps are edible, but so small and fragile that I haven’t bothered foraging them. Younger Mica Caps are better, but you can eat them up to and including the black goo stage if you wish. Despite rumours to the contrary, Mica Caps are not psychedelic, nor do they cause illness if consumed with alcohol.

As a final note, DNA analysis has found that what we call Coprinellus micaceus is actually three separate species in North America. Two of these may be present on PEI, although only one has been confirmed to date. DNA analysis is reshaping what we know about fungi, their species, and how they are related to each other.

These lovely and delicate fungi are saprobes, decomposing wood and serving as part of nature’s clean-up crew. Although they can appear in spring and summer when conditions are right, fall is the best time to find them on PEI Untamed!