In early-October, I went on a guided mushroom hike with the Peterborough Field Naturalists in Mark S. Burnham Provincial Park, a mixed old-growth forest of hemlock/cedar and maple/beech.

There, my attention was drawn by a thriving culture of Little Brown Mushrooms (LBMs) scattered on a log.

Deadly Little Brown Mushroom: Deadly Galerina marginata

It was just another pretty brown saprobic mushroom growing out of a rotting cedar log in a bed of moss. The mushroom was unassuming but rather beautiful, forming attractive clusters in a mix of moss and porous decaying wood. Their caps were convex to flat and rufous brown at the centre then fading to honey yellow towards the edge. The gills were cream-coloured and furrowed. I noticed that the stems (stipe) were streaked and sported a pale collar or annulus—remnants of the partial veil. Many were bent like the trunks of black locust in a thick forest. At the base of several mushroom stipes, I spotted a white cloud of fungal mycelium, spreading out into the moss.

I only realized after checking my field guide that this ordinary brown mushroom is one of the most deadly on the planet. This little brown mushroom turned out to be Galerina marginata, also known as Funeral Bell in the UK.  First Nature tells us that Galerina marginata contains the same deadly poisonous toxins that occur in Amanita phaloides, the Death Cap (an unassuming white mushroom) and Destroying Angels (Amanita virosa complex). In a nutshell, the α-amanitin toxin binds to and disables an enzyme responsible for making new proteins. Without the enzyme, cells can’t function, resulting in severe liver derangement and culminating in hemorrhagic liver necrosis. Without prompt treatment, the victim will experience rapid organ failure, coma, and death. Thirty grams or half a cap of Galerina (one bite) is enough to kill a human with onset of symptoms within six to 24 hours.

Galerina marginata is a saprobic fungus, which likes well-decayed conifer stumps and broadleaf tree logs. It is best seen in autumn and is found all across the northern hemisphere’s temperate zone (including Europe, Asia, and North America). According to First Nature Galerina means ‘like a helmet’ and marginata means bordered, referring to the generally paler marginal area of the cap compared with the centre.

The hygrophanous cap is initially hemispherical then becomes broadly convex or almost flat shaped. The cap, which can be 1-7 cm in diameter, is rufous brown in the centre, fading to honey yellow towards the edge. Margins may be faintly striate. Gills are close, adnate, pale cream-fawn to ochraceous honey-coloured and turn slightly rusty as they mature. The stem, 2-7mm n diameter and 2-7 cm tall, are often curved. Buff at the apex and browner towards the base, they are longidunally fibrillose below the pale ring or collar.

Good friend and naturalist Merridy Cox is fond of telling people that for every edible mushroom there is an evil twin. In this case the evil twin posed by Galerina marginata has its edible twin in the popular edible mushroom, Kuehneropmyces mutabilis (Wood Tuft or Brown Stew Fungus). The Wood Tuft is a close relative and has a similar size and colour range but a pale cap centre and darker rim. Mycologist Timothy J. Baroni cautions mushroom foragers that Galerina marginata can also be mistaken for the edible Honey Mushroom (Armillaria spp.) which occur in similar habitats, have a vaguely similar brownish colouration, but are larger, produce white spores, and have black stiff hairs on the cap.

Little Brown Mushrooms (LBMs) often go unnoticed because they are hard to spot and are usually too small to consider worth eating. The “Deadly Galerina” is therefore usually not dangerous on its own. Fungus Fact Friday contend that “the real danger from this mushroom comes when it is accidentally collected along with a group of edible mushrooms.” Velvet Foot Mushroom (Flammulina velutipes), Brick Caps (Hypholoma sublateritium), and Magic Mushrooms (Psilocybe spp.) are most commonly confused with G. marginata. All of these can be found on decaying wood and may occur together on the same substrate.

Fungus Fact Friday suggests “you should never eat any little brown mushrooms growing on wood.” Period. I agree. Not worth the risk.

Medicinal Late Fall Oyster Mushroom: Panellus serotinus

Several weeks later, in late October, I was walking in the little riparian forest by the river close to my house. It was shortly after a rain during a blustery day typical of late fall and I spotted a new crop of mushrooms on the dead silver maple by the shore. Typically grouped in clusters of five or so, the caps of this planoconvex mushroom evolved over two days from yellowish-olive green to brownish and grey-purple and after eight days into a gorgeous mauve-purple. When wet, the caps were slimy, which ForestFloorNarrative conjectures may help it in frost tolerance and/or to deter invertebrates. The gills were light yellowish tan adnate to a widening yellowish stem that tapered toward the bottom. Ultimate Mushroom calls the stem a “lateral pseudostem.” Where the gills met the stem, I noticed pores and a dark brownish band. I thought that this beautiful mushroom looked like an oyster mushroom.

That trait helped me identify it. But this saprophytic fungus isn’t actually an oyster mushroom. Even though it’s called Late Fall Oyster Mushroom, it’s not from the oyster family (Pleurotaceae); it belongs to the Mycenaceae family.

Highly regarded in Japan as a delicious edible mushroom (called mukitake), Panellus serotinus also contains some very cool medicinal properties. ForestFloorNarrative shares scientific evidence of liver-health enhancing properties. Some websites have suggested that this mushroom is potentially carcinogenic; however, these claims have been proven false. In fact, the Late Fall Oyster Mushroom has been shown to contain bio-active compounds including beta glucans, sterols, and terpinoids that demonstrate anti-tumour, anti-oxidant and anti-carcinogenic properties.

According to Ultimate Mushroom, Panellus serotinus grows mostly as clusters on hardwood logs, especially sugar maple, beech, and oak. I found my crop on the deadwood of a silver maple snag metres from the river shoreline. As its nickname tells us, this mushroom typically fruits in late fall and winter. It is quite common and widely distributed in North America.

References:

Barron, George. 2014. “Mushrooms of Ontario and Eastern Canada.” Partners Publishing, Edmonton, AB. 336pp.

Baroni, Timothy J. 2017. “Mushrooms of the Northeasern United States and Eastern Canada.” Timber Press, Inc., Portland, Oregon. 598pp.