Earlier this year, myself and collaborators published an article in the journal Mycologia entitled “Not all bad: Gyromitrin has a limited distribution in the false morels as determined by a new ultra high-performance liquid chromatography method” (Dirks et al. 2023), the findings of which are summarized here.

​Gyromitrin is a mycotoxin found in some false morels, also known as lorchels (mushrooms in the genus Gyromitra), and is highly toxic. However, methods exist to process toxic lorchels (particularly Gyromitra esculenta) to rid the mushrooms of most of their gyromitrin, allowing them to be eaten without acute illness. People rave about the taste of these mushrooms.

In North America, Gyromitra brunnea, Gyromitra caroliniana, Gyromitra korfii, and Gyromitra montana are commonly consumed without special preparation, but not without controversy. Some anecdotally regard these species to be free of gyromitrin and safe to consume after thorough cooking. Others caution against eating any lorchels for fear that they may contain gyromitrin. Before our publication, no systematic study had been conducted to evaluate the distribution of gyromitrin in lorchels or the lorchel family broadly (Discinaceae).

​For more information on the chemistry of gyromitrin and a review of the relevant literature, please see the introduction in our paper, a PDF of which is available for free here.

We developed a new gyromitrin test. Our initial analyses were entirely qualitative (whether gyromitrin was present or absent), but later we developed a “standard curve” for quantitative analysis. Most samples in our paper were evaluated just for presence or absence of gyromitrin, but some were quantified. We sampled over 60 specimens (both mushrooms and mycelial cultures) from across Discinaceae, which besides Gyromitra includes truffles in the genus Hydnotrya and cup-shaped fungi in the genus Discina. Most samples came from North America. This study was largely conducted during the first two years of the Covid pandemic and our access to specimens from other parts of the world and funding was limited.

Three important caveats need to be mentioned:

1. We went for taxonomic breadth rather than depth since this paper is the foundation for evolutionary studies. These taxa of interst only had one or two specimens tested: Gyromitra americanigigas (1), Gyromitra brunnea (2), Gyromitra caroliniana (1), Gyromitra korfii (1), and Gyromitra montana (1). Gyromitra americanigigas was recently described from Northeastern North America and is morphologically indistinguishable from Gyromitra korfii and Gyromitra montana (Miller et al. 2022). No doubt it is misidentified as G. korfii and consumed as well.
2. Our test’s detection threshold for gyromitrin is 2 mg/kg dried fungal tissue. Specimens with less gyromitrin than this would show up as negative with our test. 
3. Some data presented below are from tests conducted after our study was published.

Gyromitrin was readily detected (around 100-3,000 mg/kg dried tissue) in all tested specimens of the Gyromitra esculenta group, which consists of the following species:

• Gyromitra antarctica – South American species
• Gyromitra esculenta – European species
• Gyromitra splendida – primary species in Western North America, also present in Eastern North America and Europe
• Gyromitra venenata – primary species in Eastern North America, also present in Western North America; also present in Europe and Asia although its relative abundance compared to other species is unknown

Surprisingly, gyromitrin could be detected in very old mushrooms, including a specimen of Gyromitra venenata from the 1800s. 

Gyromitrin was also found in all tested specimens of a yellow cup fungus called Gyromitra leucoxantha, as well as a closely related, undescribed species from the Pacific Northwest (around 50-100 mg/kg dried tissue).

Gyromitrin was not detected in any other group.

​According to our phylogenetic tree, the distribution of gyromitrin could be a product of horizontal gene transfer.

Specimens that tested negative in our study might actually contain gyromitrin at low levels. A European study from 1980 tested three specimens of Gyromitra gigas (closely related to G. americanigigas, G. korfii, and G. montana) and found gyromitrin at concentrations of 1.0 and 14.7 mg/kg dried tissue in two specimens (for comparison, our threshold is 2 mg/kg); the third had undetectable levels at their threshold of 0.5 mg/kg, if it was present at all (Viernstein et al. 1980). A clinical toxicology conference abstract reported that Gyromitra caroliniana contained “minute” amounts of gyromitrin, but the data were never published and cannot be evaluted (Liang et al. 1998).

​As the Gyromitra gigas data show, intraspecific variation in secondary metabolite production is a known phenomenon, meaning even if gyromitrin was absent from one specimen of a given species it could be present in another of that same species. 

Regarding the edibility of lorchels:

• The first thing to keep in mind is that gyromitrin is dangerous. Yes, methods exist to eat gyromitrin-containing lorchels without getting acutely sick, as is common in Scandinavia. If you decide to eat gyromitrin-containing lorchels you must be very careful. Personally, I'm not going to attempt to eat any Gyromitra esculenta group mushroom. 
• In my opinion, the best evidence for the edibilty of species like Gyromitra americanigigas, Gyromitra brunnea, Gyromitra caroliniana, Gyromitra korfii, and Gyromitra montana is the number of people who consume them without getting sick. They are presumably cooking them thoroughly and this is highly recommended for a safer (and tastier!) meal. There is no evidence of extraordinary poisoning from these mushrooms (most edible mushrooms, from chicken of the woods to morels to shiitake, have some reports of people getting sick due to misidentification, putrescent mushrooms, allergic responses, or perhaps unknown secondary metabolites). 
• For these five widely consumed species, we cannot definitively say that they do not produce gyromitrin, but rather there is no (strong) evidence that they produce gyromitrin (but see Liang et al. 1998). Given that Gyromitra gigas produces gyromitrin, I would bet that other Gyromitra gigas group species produce gyromitrin at low levels. We are going to test more specimens with heightened sensitivity.  
• The question that a prospective lorchel consumer must ask themself is, therefore, are they comfortable consuming species that might contain small amounts of gyromitrin? An answer either way is OK! Some things to consider: As a volatile substance, gyromitrin can be cooked away. Is it ever completely cooked away? Probably not. As a carcinogen and genotoxic substance, how much gyromitrin is too much gyromitrin? We don't know. Some studies suggest gyromitrin poisoning could be a factor in the development of neurodegenerative diseases (Lagrange et al. 2021). I expect as long as you don't get a large dose of gyromitrin you will be OK (I mean, not everyone in Finland who's eating well cooked Gyromitra esculenta group mushrooms has neurodegenerative disease?). But this is emerging research and is difficult to study. For the five species mentioned above that likely contain little to no gyromitrin, they might just deserve a California Proposition 65 carcinogen warning, a label that everything seems to have and nobody seems to care much about. 
• You must always positively identify the mushrooms you are consuming. "Gyromitra brunnea" is poisonous if you are actually eating Gyromitra venenata that you misidentified and have not prepared properly.
• I guess the usual disclamers should be said – be safe, these thoughts are my opinions and I'm not responsible for your decisions, and I wish you well. 

Lagrange, E., Vernoux, J. P. P., Reis, J., Palmer, V., Camu, W., & Spencer, P. S. S. (2021). An amyotrophic lateral sclerosis hot spot in the French Alps associated with genotoxic fungi. Journal of the Neurological Sciences, 427(June), 1–8.

Liang, Y.-H., Eisenga, B. H., Trestrail, J. T. I., & Kuslikis, B. (1998). Gyromitra mushroom species and their monomethylhydrazine content. Platform Session 1: Part 2, Journal of Toxicology: Clinical Toxicology, 36(5), 527. 

Miller, A. N., Dirks, A. C., Filippova, N., Popov, E., & Methven, A. S. (2022). Studies in Gyromitra II: Cryptic speciation in the Gyromitra gigas species complex; rediscovery of G. ussuriensis and G. americanigigas sp. nov. Mycological Progress, 21(81), 1–13.

Viernstein, H., Jurenitsch, J., & Kubelka, W. (1980). Vergleich des giftgehaltes der lorchelarten Gyromitra gigas, Gyromitra fastigiata und Gyromitra esculenta. Ernahrung/Nutrition, 4(9), 392–395.

The 2022 mushroom season is here! Yet again, I ask for your assistance in collecting lorchels and related mushrooms (Discina, Gyromitra, and Hydnotrya) to help determine the distribution, genetics, and evolution of gyromitrin. ​Gyromitrin is a mycotoxin produced most infamously by Gyromitra esculenta, a deadly poisonous mushroom that is consumed as a delicacy in Finland (after being properly prepared to remove most of the gyromitrin). We actually have no idea which genes make gyromitrin, how gyromitrin biosynthesis evolved in lorchels, or for that matter which species produce gyromitrin. I’m attempting to answer these questions for my PhD research! If you'd like to read more about the project, you can find a longer description in the research section of my website.

If you were able and willing, I’d greatly appreciate donations of any and all fungal specimens in the family Discinaceae (Gyromitra, Discina, and Hydnotrya). If you would like to donate any that you find for this project, a few things need to happen for the specimen to be usable:

For each specimen I receive I will attempt to sequence the ITS and LSU rDNA barcodes. I will share these data with you as well as my sequence-based identification. Some specimens may be selected for gyromitirn analysis, culturing, or whole genome sequencing. 

​Something important to note: your specimens are received as donations. Unfortunately I do not have access to fund to reimburse you for time or expenses related to your donation, including shipping costs, and the specimens cannot be returned to you. Rather, they will be accessioned at the University of Michigan fungarium for long-term safekeeping and storage. Make sure to make a “split” (keep a portion of the mushrooms for yourself) if you are interested in holding onto it for personal study. For this project I have been working with some fungarium specimens that are over 100 years old. Your donated specimens will live on as research subjects long in the future, perhaps for centuries to come.

Thank you for sharing your time, energy, and knowledge in the form of mushrooms donations. Your specimens have been invaluable so far and I am greatly appreciative of all your help!

The process by which a mushroom earns the badge of "edibility" is mysterious and fascinating to me, a product of time and place and culture. Ischnoderma resinosum, or the velvet polypore, is one that is generally regarded as inedible, and not for bad reason – the mature sporocarps are tough tough. But there seems to be a growing recognition that the young polypores are indeed edible, and not half bad at that. I myself was surprised when I first learned about somebody eating these, a Russian mushroom hunter in Madison, Wisconsin. Not only did he eat the velvet polypore, but he claimed it was his very favorite mushroom of all. I first sampled Ischnoderma resinosum with my older sibling in Toronto. After explaining to them that this mushroom was safe to eat because a knowledgeable Russian said so, and enjoying the meal with no health repurcussions, they now send me pictures excited to have found the "Russian polypore" again – a good example of the randomness and obscurity of the birthing of some common names.

MycoBank Taxonomy: Fungi, Dikarya, Basidiomycota, Agaricomycotina, Agaricomycetes, Phallomycetidae, Gomphales, Gomphaceae, Gomphus

Now and again, a supportive fan of the 1001 Mushroom Project will offer up some of their mushrooms for me to eat and blog about. Because I want to go through the whole process myself (finding, identifying, preparing, and eating a new species), I almost always decline their generous donations, But when a mushroom hunter shared with me photos of these gorgeous lilac "chanterelles", Gomphus ludovicianus, and asked if I'd like them for eating – they'd collected them before but weren't a big fan, or eating any mushroom for that matter – how could I say no? 

ACTION ITEM: Sign a petition in support of students who want to change the name of the Entomological Society of America's annual competition, the Linnaean Games, and read their open letter to the ESA board on why it is necessary to do so. The text below offers further encouragment and background information, which is certainly relevant to mycologists as well.

Carl Linnaeus is one of many white historical figures whose legacy has been warped over time to hide away problematic aspects. We learn about Linnaeus at a very early age as the inventor of Latin binomials, a system of naming living organisms that is now highly encoded and regulated process for all life forms, including fungi. But what we don't learn about in school is his deeply racist beliefs of white supremacy, which were preserved in his scientific writings as an ordination of human races and ascription of pejorative moral and behavioral qualities to non-white people. It's awful stuff. As Linnaeus is the father of taxonomy, he is equally the father of scientific racism. 

MycoBank Taxonomy: Fungi, Dikarya, Basidiomycota, Agaricomycotina, Agaricomycetes, Polyporales, Polyporaceae, Polyporus

This magnificent and exceptionally delicious mushroom is universally regarded as rare. While mushroom hunters may never see Polyporus umbellatus, if you do find it, you will be able to come back year after year to the same location for a new harvest. P. umbellatus grows from the ground as a parasite and saprobe of the roots of hardwood trees. It appears from May to October (spring and fall, but typically not summer) across North America, growing as a fractal rosette of umbrella-shaped fronds. For some people, the mushroom has less appeal than what is going on in the soil. Over many years perhaps, P. umbellatus forms a large subterranean mass called a sclerotioum. Sclerotia are hard resting structures capable of longterm dormancy for survival in drought and cold. Some sclerotia are small like seeds and others are as big as basketballs. In the case of P. umbellatus, the sclerotia can be enormous, more than a foot in diameter, with a solid, corky interior and black rind. In traditional Chinese medicine, the sclerotium of P. umbellatus goes by the name Zhu Ling and is taken for a number of purposes, in particular as a diuretic (to stimulate urination).

MycoBank Taxonomy: Fungi, Dikarya, Basidiomycota, Agaricomycotina, Agaricomycetes, Polyporales, Fomitopsidaceae, Laetiporus 

Laetiporus sulphureus is a magnificent mushroom, easily identifiable by its bright yellow pore surface and overlapping, shelf-like growth on the standing or fallen trunks of hardwoods. It might just be my all-time favorite mushroom. The young mushrooms check all the boxes of a great wild edible: 

• Easy to identify (no poisonous lookalikes, beginner-friendly)
• Impressive appearance
• Fantastic taste, versatile, and wonderful texture (like chicken, lobster, or crab)
• Often found in large to enormous quantities
• Typically easy to clean
• Reappears in the same spot year after year 
• Money maker

That's right, if you find a mega flush, there will likely be more chicken than you can eat yourself and others will be eager to buy it from you. In Ann Arbor, chicken of the woods fetches about $16 a pound. The flush documented here, which I found when the mushrooms were just starting to bubble out of a large downed trunk, yielded about 50 pounds of tender chicken over the span of a week. 

MycoBank Taxonomy: Fungi, Dikarya, Basidiomycota, Agaricomycotina, Agaricomycetes, Polyporales, Polyporaceae, Noefavolus

Mushrooms referred to as the hexagonal-pored polypore, or Neofavolus alveolaris, are common and widespread across eastern North America in the spring. They can persist through the summer, fall, and even into the winter, becoming hardened and bleached over time. Despite the common name, the pores are rarely perfectly hexagonal, instead usually vaguely and irregularly polygonal. Regardless, the hairy/scaly orange cap and large, elongated pores make this mushroom easily recognizable – that is, if we actually knew what we were identifying. Neofavolus alveolaris represents a number of cryptic species, which may not be all that suprising given that name has been applied to similar mushrooms occurring in temperate and boreal areas across the entire Northern Hemisphere (Sotome et al. 2013).

Mycobank Taxonomy: Fungi, Dikarya, Basidiomycota, Agaricomycotina, Agaricomycetes, Agaricomycetidae, Agaricales, Psathyrellaceae, Coprinellus

Coprinellus truncorum (or more commonly referred to as C. micaceus - more about that later) is an inky cap, which means before you know it, the mushroom will enzymatically digest itself in a soppy process called deliquescence. Inky caps are really the milquetoasts of the mushroom world, turning into complete mush soon after fruiting. Deliquescence is much more than feebleness, though. It is a process of spore dispersal that has evolved independently in multiple lineages of mushrooms. Deliquescence starts at the edge of the cap and moves towards the stem. Meanwhile, the spores mature in the same pattern, but one step ahead of the destructive enzymes. As a result, mature spores are always at the edge of the dissolving cap - a perfect position to catch air currents for dispersal. If you are interested in learning more about inky caps and their taxonomy, check out Michael Kuo's page on the topic.

Mycobank Taxonomy: Fungi, Dikarya, Basidiomycota, Agaricomycotina, Agaricomycetes, Agaricales, Mycenaceae, Sarcomyxa

I bemoan the appearance of this beautiful mushroom. The colors of the cap are wildly variable, ranging from ochre to olive-brown to steely blue-grey. It's subtended by a cute stumpy stem that is sometimes freckled. The gills are close and have an orangey-yellow color. So why does it bring me sadness? I divide my year in half: six exuberant months of mushrooms and six horrid ones of frigid temperatures, denuded vegetation, and dormant fungi. True to its name, the late fall oyster signifies the end of the mushroom season and the beginning of the long winter hibernation. In the Great Lakes region, you can find Sarcomyxa serotina growing from hardwood logs in late October and November. And, sorry to say it, there won't really be any edible mushrooms popping up again until the end of May. 

Mycobank Taxonomy: Fungi, Dikarya, Basidiomycota, Agaricomycotina, Agaricomycetes, Agaricales, Agaricaceae, Lycoperdon

Mycobank Taxonomy: Fungi, Dikarya, Basidiomycota, Agaricomycotina, Agaricomycetes, Agaricales, Pluteaceae, Pluteus

Some fungi are "rare" simply because they are obscure and nobody besides myconerds looks for them. P. aurantiorugosis, on the other hand, is a gorgeous, photogenic mushroom. Despite the fact it stands out, it is seldom documented, and thus can be regarded as truly rare. For example, Michael Kuo from mushroomexpert.com has only found it once in 20 years of mushroom hunting.

I am continuously surprised by the forest behind my house. It's a cruddy place - buckthorn, honeysuckle, and box elder run the woods; trash is scattered about or heaped into dumpy piles; and invasive fungal pathogens are devastating the hardwood trees. Yet, it is full of treasures. In addition to the truffle I recently found, it is also where I discovered this mushroom. The scarlet-red fruiting bodies were growing off the end of a fallen, decorticated trunk. I puzzled over them for a long time. They were so distinct yet they didn't fit any description in my head. Once I noticed the free, pinkish gills, I knew it was a Pluteus species and identification was only a quick Google search away. To my surprise, this was the first documented encounter of P. aurantiorugosis in Michigan since the 1970s!

Mycobank Taxonomy: Fungi, Dikarya, Basidiomycota, Agaricomycotina, Agaricomycetes, Agaricales, Agaricaceae, Calvatia

Mycobank Taxonomy: Fungi, Dikarya, Ascomycota, Pezizomycotina, Pezizomycetes, Pezizales, Tuberaceae, Tuber

To celebrate the accomplishment of the binary version of this project (1001 = 9), I endeavored into the exquisitely funky world of truffles. While some people make the distinction between “true truffles” (Tuber spp.) and “false truffles” (everything else that grows underground), I’ll refer to them all as truffles. Recently, I learned that truffles are all around us. There are actually over 40 Tuber species native to North America (Guevara et al. 2013 listed 38, and more have been described since) and if you consider underground fungi in other genera, there might be hundreds of species present in the United States!