© Buck McAdoo

Back to Main Menu

Danny’s DNA Discoveries – Porotheleaceae of the PNW (Marasmiineae)
by Danny Miller

Click here for my Pictorial Key to Clitocybula, Gerronema, Megacollybia and other misc. white spored wood inhabitors.


This family (including, perhaps, the Cyphellaceae) used to be called the Hydropoid fungi. Inside this family, Megacollybia is paraphyletic inside Gerronema so some revisions to those genera may be made (see the discussion below).

Although most genera are gilled, Porotheleum itself also contains a poroid/cupulate crust.

Although an ITS tree might show these genera intermingling with the Cyphellaceae, an LSU tree in a 2022 study shows the two families as separate. They are at least close sister families to each other, and I don't think we've heard the final word on if they should be kept separate or combined into one big family.

abundant common uncommon rare - colour codes match my Pictorial Key and are my opinions and probably reflect my bias of living in W WA. Rare species may be locally common in certain places at certain times.

Summary of Interesting Results

Here are some of the newest, most interesting results of the study:

  • tbd

Hydropus, Leucoinocybe and Porotheleum

Hydropus 'marginellus PNW01' - our only known local species is a brown "Mycena" growing on wood with brown marginate gill edges and weakly amyloid spores. Smith observed that a watery liquid may exude when it is cut. The genus is separated from Mycena by its different cap cuticle structure (for instance, erect or spherical elements). Lucky, no local Mycenas look exactly like it (none have specifically brown marginate gill edges). Our local species is 4% different from the couple of EU sequences we have so perhaps ours is in need of a new name.

Leucoinocybe PNW01 - like Hydropus, these are very much like Mycena, with amyloid spores, but perhaps a different cap cuticle. Our local species, only found once in WA and once in OR, had blue tones like Mycena amicta in the WA collection, but presumably doesn't have the peelable cap cuticle and has distant decurrent gills instead of close adnexed gills.

Mycopan was split from Hydropus for M. scabripes and M. pseudotenax, and Mycena quinialtensis belongs in Mycopan as well. They are genetically different than Hydropus and Leucoinocybe but otherwise very difficult to distinguish.


Hydropus 'marginellus PNW01' © Yi-Min Wang (2 images),     Leucoinocybe PNW01 © Yi-Min Wang (3 images)


Porotheleum PNW01 - a cool omphalinoid with a darkening stem and an opaque, fibrillose cap. It is remarkable how the same genus can have this gilled mushroom and a crust.

Porotheleum PNW02 - another omphalinoid with a darkening stem and sometimes a translucent cap (but sometimes a cap much like PNW01), on roots of red cedar and maybe madrone. I don't yet know how to reliably separate it from PNW01.

Porotheleum fibriatum EU - a cool poroid/cupulate crust. It has been sequenced from the EU and ENA, but we need local sequences to confirm that our species is the real thing too.


Porotheleum PNW01 © Yi-Min Wang,     P. PNW02 © Matthew Koons (2 images),     unsequenced Porotheleum cf fimbriatum (from CA) © Christian Schwarz

Gerronema, Megacollybia and Clitocybula

Work still needs to be done to sort these out. See below.


Clitocybula familia NY - a tightly clustered greyish-tan small wood inhabiting species. Amyloid spores. One WA sequence matches a few east coast sequences including one Antonin used in his study of the family.

Clitocybula cf abundans NY - more solitary (only somewhat clustered) with a depressed, radially streaked greyish cap. Attempts to sequence local collections failed so far, and there are no east coast sequences either. We need local and eastern collections to see if this is our species.

Clitocybula 'lacerata PNW01' - very similar with larger spores. We have the neotype sequence and that study showed that Europe has 3 cryptic species, each with variable appearance and spores, at least 4% in ITS apart from each other. Our WNA species is close to those three, but clearly distinct, and may also be cryptic, recognizable only by geographic area. It has been collected and sequenced from CA and WA. One of the other cryptic EU species had collections that resembled C. abundans.

Clitocybula familia © NAMA and the Field Museum of Natural History,     C. cf. abundans © Danny Miller,     C. 'lacerata PNW01' © Debbie Klein (from CA) and Connor Dooley (from WA)


Clitocybula oculata OR - described as greyish-brown with a sooty disc, furfuraceous all over and short decurrent gills. But what is it? It is only known from one collection in Oregon  in 1911. The spore size is unique, but we should sequence it to find out if it is indeed placed in the correct genus, especially considering the unanswered questions that follow.


Gerronema atrialbum WA - blackish cap and stem contrasting with white gills. A large, very thin-fleshed mushroom with strongly decurrent gills, found on buried wood or debris. We have a half dozen WA sequences that definitely represent this species.

Formerly placed in Clitocybula because of its amyloid spores, but genetics moved it to Gerronema, supposedly with inamyloid spores. But that may not be the final word, since Gerronema may not monophyletic; Trogia and Megacollybia seem to live inside it. Nothing further can be determined until the type species of Gerronema, G. melanomphax from Argentina is sequenced to find out where the true Gerronema are in that complex. Then, perhaps, Gerronema will be split or Megacollybia will be moved to Gerronema. See below.

Gerronema atrialbum © Yi-Min Wang


Megacollybia fallax ID - a larger grey-brown wood inhabitor with a radially streaky cap that may split, gill edges that might get eroded in age, and white rhizomorphs at the stem base. Inamyloid spores and these rhizomorphs should separate it from Clitocybula. We have the type sequence. Even though the EU species Megacollybia platyphylla EU was reported here, one study did not find it anywhere on the west coast. If you think you find a different species of Megacollybia here, save it.

This genus, along with Trogia, might live inside Gerronema and therefore might not merit its own genus as currently understood. Although a 2019 2-gene study showed that Megacollybia was in fact distinct, but didn't use many species, and further research shows it is not. Stay tuned.

unsequenced Megacollybia fallax © Andrew Parker


Back to Main Menu