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Fall ’shrooms: Troops of tiny fungi

Updated: Jan 23, 2022

The first week of autumn last year (2021) felt like the autumn days of my youth in Virginia — crisp and dry, before climate change stretched out the summer. But after that brief cool snap, temps rose again into the 70s and even low 80s through the first two weeks of October.

The mild weather, along with rainy stretches, brought out more and more fungi on Briar Ridge. While some were familiar to me from my 'shrooming in Old Hollow, a few were new, including a troop of tiny ones. Before we get further, I should mention a rabbit hole I went down in writing about this group of lilliputian mushrooms, less than an inch tall, and the correct collective term for them.

A cluster, a troop, or just gregarious mushrooms?

Scientific terminology can be arcane and, in some cases, squishy (my technical term), depending on the source. And the constant evolution of taxonomy as more technical tools become available, such identification through DNA, can be both illuminating and confusing. While I have several good glossaries of most scientific terms used by mycologists, some less-formal jargon that appears in various sources I check when doing my research is not included.

Not a mycologist or 'shroomer, just a big fan of the appearance of fungi and their role in the web of life, my tendency has been to call mushrooms that grow in proximity to each other a "colony," like some plants and animals. Knowing the arcane nature of mycology, I started thinking that perhaps that was not the right term and went searching on the internet to find a collective noun that is more commonly used in this field.

I found few sources that addressed this, and none of my usual, well-vetted websites and printed references seemed inclined to use specific terms for groups of mushrooms. I finally stumbled onto "troop" in several sources, which gave me a keyword, which then led me to "cluster." The few sources that tried to explain the use of these terms said that "troop" applied to a group of mushroomsthe fruiting bodies (reproductive organs of fungi)that grew closely together but not as closely as a "cluster," which applied to those that grow so close together that they appear to be coming out of the same spot on the ground.

Both terms are to be distinguished from "gregarious," which applies to a species that grows a bit further spread out than a cluster or troop. Of course, these terms are relative, but I try to embrace the jargon of science in my own writing where appropriate, while also doing my best to explain any such terms. It doesn't help in this case that two of the terms for groups are nouns, while "gregarious" is an adjective, but I digress (further).

Tiny soldiers?

So back to the troop of tiny mushrooms I found. Mushrooms often change color as they age, and that was the case with these. Most of the mushrooms were white when I discovered them, in September. I took a few quick shots with my phone to help with ID, thinking I'd come back with my camera and macro lens later.

Unfortunately, the troop disappeared before I returned, but another popped up in the same spot during a rainy stretch a few weeks later. They were in a vulnerable spot, at the edge of the driveway, so I went out to get more photos before they disappeared again.

Examining the troop to choose a specimen, I noticed most were starting to turn gray, with the orange-brown dot in the center of the cap's top showing more clearly. I picked a nice specimen and checked the stalk and underside of the cap, both of which are important in mushroom ID but hard to examine while the mushroom is still growing in the ground, especially with such Lilliputian species. I also took shots of the specimen from several perspectives, including the underside of its cap, while the mushroom was still fresh.

From the top, the little mushroom looked like an inkcap (also known as inky cap), in the genus Coprinus. Inkcaps earned their name through turning black as they age, before they turn into slime and disappear. The genus is in a large group of mushrooms that have gills — thin, papery structures that hang vertically under the cap and produce the fungus' spores (like seeds of a plant). The gills on these little mushrooms were gray to begin with, but the cap was also turning gray, which made its pleats stand out. In visiting the troop, over time I found that, although the mushrooms' gills were a bit dark, none of the mushrooms turned black before they died.

Checking in William C. Roody’s Mushrooms of West Virginia and the Central Appalachians for Coprinus species, I found that one inkcap that does not turn black, prosaically named Non-inky Cap Coprinus (Coprinus disseminatus). The more common, and I think more endearing, name they go by is Little Helmets. The fact that the gills were not appreciably darker than the rest of the cap helped with the ID.

A Little Helmet, standing a whopping three quarters of an inch tall

While I was pretty confident of the ID at this point, I was still wondering about Roody's description of where it grows: on the decaying roots of broad-leaved trees, “especially on or around stumps.” But he adds that they also grow in grassy places “where there is buried remains of old stumps and root systems.”

While mushrooms of terrestrial fungi are what we see above ground, the main body of many fungi lives underground and can cover much more area than the fruiting bodies do. So while many mushrooms seem to thrive is what appears to be mostly earth, below that earth can be the rotting roots or remains of trees. Although this troop was growing in the lawn, it was near an old (nonnative) Blue Spruce tree, which is a conifer. However, the surrounding area is dominated by broad-leafed hardwoods, with a network of roots of current and past hardwoods probably lying just under the lawn.

On October 11, after a stretch of mild, rainy days, I found another small troop of these sweet little mushrooms, and some other fungus species. It was along a forest path my dog and I travel most days. I had noticed other fungi growing on the path, as I've seen frequently on or at the edge of forest paths.

Little Helmets turn gray as they age

While I've often thought it strange that mushrooms would prefer a well-trod path to areas deeper in the forest, where there is more rotting detritus to feed on. But maybe host roots lie below the packed earth, and the paths may offer other benefits. Like us, many animals regularly follow paths they or other species have made through forests because it’s easier than bushwhacking. A lot of these animals like to territorially mark a trail with scat — some choosing a high point (such as a rock or leaf pile) to anoint. Other species just travel these paths so frequently that it's just happenstance that they leave behind such signs of their passing. Those extra doses of fertilizer, along with increased light on forest paths, may make paths more conducive for some fungi to flourish.

To be, or not to be ... a puffball?

On my regular mushroom hunts, I also found a cluster of another small species, albeit a bit heftier than the Little Helmets — about 2 inches across. It looked like a puffball and was not too far from one of the troops of tinier Little Helmets. I kept an eye on the little cluster to see if the mushrooms' form changed as they grew, but they suddenly disappeared.

Fortunately, I had taken a few photos to help with ID. In researching the mystery species, I was surprised to learn it was not a puffball but rather a bolete, Scleroderma citrinum, commonly known as Common Earthball, Common Earth Ball, or Pigskin Poison Puffball. Also in the area was a huge (several inches across), misshapen mushroom I’ve yet to ID, or perhaps a fungivore fungus on top of a mushroom, consuming the latter (it happens).

While these mushrooms resemble puffballs, they are actually boletes, Common Earthballs

While these fungal blooms were soon gone, another tiny, globular one popped up. It also looked like a puffball, but checked Roody's guide to be sure and to get the species name. This mushroom was a puffball, commonly known as Spiny Puffball (Lycoperdon americanum). A similar species, Gem-studded Puffball (Lycoperdon perlatum) also has spines, but its spore case is smooth after the soft "spines" fall away, while the Spiny Puffball's spines leave pits or net-like scars when they fall away, according to Roody. The Spiny also darkens with age, as the ones in question did, while the Gem-studded stays white.

This Spiny Puffball, usually round, appears to be damaged
An old Spiny Puffball that has lost its spines

One of the things I don't like about winter is that it spells the end of the bloom season for most mushrooms, but spring will come, bringing another combination of blooms with it.



Adventures in Nature

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