Pleuroflammula tuberculosa: A Mushroom Mystery Solved
There is a story behind every mushroom. Pleuroflammula tuberculosa just needed a couple of centuries to complete one.
By Ann Simpson
Once upon a time there was a mushroom that didn’t seem to exist, even though there were those that had claimed to have seen it. Then there were those that did see it, but insisted it was something else. The history of a mushroom can occasionally be as fascinating as finding the actual specimen, especially with one that needed almost 250 years to finally receive its due recognition.
The species was first described by the famous German mycologist and botanist Jacob Christian Schäffer in 1774 when he named it ‘Agaricus tuberculosus’ and although it was cited under this name in a work published in 1800, it was really only the beginning of an era of uncertainty surrounding the question of what this mushroom should be called.
Over the next 230 years this same little mushroom was written about several times, and always as something else:
Agaricus curvipes Pers., Syn. meth. fung. (Göttingen) 2: 312 (1801)
Agaricus tuberculosus Schaeff., Fung. bavar. palat. nasc. (Ratisbonae) 4: 34 (1774)
Agaricus vitellinus Batsch, Elench. fung. (Halle): 83 (1783)
Dryophila curvipes (Pers.) Quél., Enchir. fung. (Paris): 68 (1886)
Dryophila tuberculosa (Schaeff.) Quél., Enchir. fung. (Paris): 68 (1886)
Gymnopus curvipes (Pers.) Zawadzki, Enum. plant. Galic. Bucow. (Breslau): 162 (1835)
Hypodendrum tuberculosum (Schaeff.) Overh., N. Amer. Fl. (New York) 10(5): 280 (1932)
Pholiota curvipes (Pers.) Quél., Mém. Soc. Émul. Montbéliard, Sér. 2 5: 250 (1872)
Pholiota muricata var. curvipes (Pers.) P. Kumm., Führ. Pilzk. (Zerbst): 83 (1871)
Pholiota tuberculosa (Schaeff.) P. Kumm., Führ. Pilzk. (Zerbst): 83 (1871)
Pholiota tuberculosa var. curvipes (Pers.) P. Roux, Guy García & Chapon, in Roux, Mille et Un Champignons: 13 (2006)
(Source: Names Index, Species Fungorum)
The 2006 study should have cemented our little mushroom firmly in the Pholiota genus (Family Strophariaceae), though there still did not appear to be a consensus on what this mushroom was actually called – there are several different trails in the research that reference this to being either Pholiota curvipes, Pholiota tuberculosa, and Pholiota tuberculosa var. curvipes. Even today, if you are planning to search for identifying specifics on Pleuroflammula tuberculosa, your best approach is still to look it up under one of these inactive Pholiota species (Pholiota tuberculosa seems to be the preferred name used in later years).
One might be wondering, just how did we learn about Pleuroflammula, and how does our mushroom fit into this seemingly ever-changing taxonomic mix? It started in 1946 with a study by Rolf Singer, who was researching species within the Crepidotus genus (Family Crepidotaceae), and he proposed a new genus called Pleuroflammula containing seven distinct species that he believed should not belong in Crepidotus due to the presence of a veil – a thin membrane that can cover the cap and stem of very young mushrooms. Singer conducted additional studies on his new genus though his research appears to be limited to macroscopic features, and that seems to have prevented our mushroom from being part of his proposed genus at the time.
A more detailed study of Pleuroflammula by Egon Horak was published in 1978, this one containing microscopic findings and proposing three additional species, bringing the total to ten. Most of the species examined were collected in the Southern Hemisphere (only two from North America), and while Horak believed that Pleuroflammula could be more widespread, our mushroom was still not included amongst these.
Then, in another study published by Horak in 1986, our little mushroom got his attention. This study was not focused on Pleuroflammula, but rather on disputed species within other genera, and one of these was Pholiota tuberculosa, which Horak transferred to the Pleuroflammula genus based on macroscopic and microscopic features. Horak is now credited with the name of our mushroom, though it would take another 35 years for his conclusion to be accepted as more than a synonym for Pholiota tuberculosa.
There was a revival of the conversation in the decade after the 2006 study, mainly on message boards and forums related to mushroom observations. Our mushroom was being found by these observers and some were definitely not satisfied with the taxon placement in Pholiota, even including one or two references to the previously proposed genus of Pleuroflammula.
Finally, in a study published in 2020, closure for our mushroom arrived. A specimen labeled as Pholiota curvipes (aka P. tuberculosa) was included in a detailed phylogenetic study conducted of mushrooms collected during the 1960’s for placement in the Pholiota genus, and one of the findings of this study was that the DNA characteristics of this specimen were distinct enough to formally establish the genus of Pleuroflammula. Our mushroom was transferred to this new genus and assigned the name originally proposed by Horak – Pleuroflammula tuberculosa.
So, let’s meet our little mushroom that was the source of all this conjecture and debate. I have been fortunate to find it quite a few times here, both before and after its taxon swap. It can be found during late summer and early fall in temperate zones throughout North America, Europe, and even parts of Asia. Pleuroflammula tuberculosa is saprophytic, meaning it will be found growing on a dead or decaying host, which in this case would be a hardwood, and aspen is one of its preferences. It reportedly can also be found on hardwood debris or sawdust, though my sightings of it have only been on complete or partial logs of fallen aspen trees.
It is on the smaller side, usually 2 to 5 cm in size, and at first glance one might suspect some type of Strophariaceae genus, given its general colouring and veil remnants. When young, it can be a bright yellow, later becoming more ferruginous (rust coloured). The stem is yellow, often with a fibrillose zone near the apex where pieces of the veil still adhere. The cap surface is covered in slight scales, and the cap edges appear uneven with several hanging remnants of the veil.
The gills are somewhat close, adnate with subgills, and are bright yellow when young, later becoming more rust coloured in maturity. One of the more interesting features is the distinctive gill edges, and these are a prominent key for identification. The edges will be smoother when young, but quickly develop crenulated sections, eventually becoming fully crenulated (a term also used in botany to describe leaf margins that are finely scalloped, or notched). The spore colour is cinnamon, which contributes to the later rusty appearance of the gill surface.
So, if you are out and about, be on the lookout for this fascinating species. It is more widespread than originally believed, and if you have the good fortune to come across one, take a moment and think about the long journey this little mushroom has completed, and how it finally became the mushroom we currently know today as Pleuroflammula tuberculosa.
So as through a glass, and darkly
The age long strife I see
Where I fought in many guises,
Many names, but always me.
George S. Patton, “Through a Glass, Darkly” (1922)
Publisher’s note: All photos courtesy of Ann Simpson.
“Pleuroflammula tuberculosa: A Mushroom Mystery Solved” ©2025. Ann Simpson and The Renaissance Garden Guy
Ann Simpson is a regular contributor to The Renaissance Garden Guy. She resides in Bridge Lake, British Columbia, where she remains in constant pursuit of her mycological quarry. Click here to follow Ann Simpson on X (Twitter), and find her on Bluesky at Ann in Bridge Lake at Bluesky.
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Fantastic story! So much to be learned from nature…
Great photography!
Thank you for sharing this gem of knowledge 🍄🌸
Thank you for reading the article, Roxxy, and thank you for commenting. I completely agree. The natural world is filled with remarkable stories. Ann’s expertise, knowledge, and research skills allow her to uncover those stories in truly entertaining and informative fashion. Her passion for her work is very evident, and it’s wonderful that she shares that passion right here in The RGG. Thanks once again, Roxxy!
Amazing story over many years. It ends up where it began. Fascinating.
Agreed, Rick. This particular mushroom’s story truly makes for great reading. Ann’s research in uncovering its twisting trail of taxonomy and nomenclature is beyond commendable, and her fieldwork and photography really bring this fascinating little mushroom and its rich and mysterious history to vibrant life. Thank you so much, Rick, for reading Ann’s article and for commenting. It’s much appreciated.
Very interesting article that reminded me that there is more to be learned about the natural world every day. Ann’s articles bring to light the complexities of the mushroom world in an enjoyable, educational, and easy to understand format. I really enjoy reading them, and I look forward to her next piece.
I’m with you there, Kevin. Ann’s research skills are peerless, her photography is breathtaking, and her writing is so enjoyable and informative. It’s impossible to come away from an Ann Simpson article without at least a few additional IQ points! Thanks for reading and commenting, Kevin!
Awesome article on mushrooms. Thank you for publishing this.
It’s a pleasure to publish great articles like this one in The RGG, Annie. Ann’s an amazing writer, and an incredibly thorough researcher and talented photographer. I’m entirely honored to feature her work here. Thank you so much for reading the article, Annie, and for commenting here!
Very interesting article. It reminds readers that there is so much to learn about the natural world and its mysteries and wonders.
Thanks for reading the article, Kevin. I agree with you. Ann’s research uncovered an amazing natural history lesson – I loved reading her article. And thanks for commenting here, Kevin. It’s much appreciated.
Thank you, Ann.
Long live the mushroom!
Hear, hear! Great comment, Lane!
Thanks so much, Lane – I fully endorse that statement!
Always great to see your photos and learn so many details of these fascinating mushrooms, Ann! And there’s poetry to boot!
I’m taking the liberty of buttin’ in, Lisa… I completely agree. Ann’s work is always as beautiful as it is fascinating. And the poetry… just wonderful!
Thanks so much, Lisa! I really appreciate hearing that you enjoyed it, and I’m grateful to John for allowing me the opportunity to share my love of fungi with his readers. I had a lot of fun putting together this little piece of mushroom history.