© Fred Rhoades

Back to Main Menu

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

Click here for my Pictorial Key to the Collybioids, where most Omphalotaceae are found.


This is one of the largest families in the Marasmiineae sub-order, containing many species of collybioid stature (and sometimes marasmioid stature). Usually, a white spored mushroom with a tough, cartilaginous stem is somewhere in this sub-order (not necessarily here) but many species could not be properly placed until DNA came along. There is a vast "white spored multitude" of species, as they say in Mushrooms of the Redwood Coast, and it can be very difficult to identify a mushroom even to sub-order never mind family never mind genus. This is definitely a case of "learn the species to learn the genera" as often, nothing much unites them.

Given that Campanella from the Marasmiaceae appears to be closer to this family than the family it is currently placed in, and the fact that there is not much genetic distance between the two families, the Omphalotaceae may not deserve their own family and it may be best to think of the Omphalotaceae as part of the Marasmiaceae, the family that contains most other mushrooms of marasmioid stature.

These have not been well studied in the PNW, and we keep seeing species we don't recognize, so I knew we would find surprising new species when we starting sequencing them. They are called collybioid because all mushrooms of that stature used to be called Collybia. Then we found out that the group was very artificial and those mushrooms were split, and it turned out that the first and true Collybias were atypically small and actually part of Clitocybe in the Tricholomataceae, so many collybioid mushrooms were moved to Gymnopus. Then DNA discovered that some Gymnopus were inside Marasmiellus, and some former Marasmiellus didn't belong there. Finally, it was discovered that Marasmiellus was a word that shouldn't be used, since Collybiopsis is an older synonym for that genus. There is no good way to tell Gymnopus and Collybiopsis apart without DNA, so I am treating them in one section.

All three garlic mushroom clades are in this family. You can identify your garlic-like sub-order Marasmiineae mushrooms this way:

  • Gymnopus are usually ~5cm across collybioids, except for 'Micromphale' arbuticola, which is a ~1cm marasmioid on the special habitat of madrone bark. They have repent cap cuticle hyphae.
  • Paragymnopus are small ~1cm marasmioids with repent cap cuticle hyphae whose odor is different, said to be more like rotting cabbage but somewhat garlicky.
  • Mycetinis are small ~1cm marasmioids with a spherical cap cuticle like Marasmius. This is why we used to think they were in Marasmius and their nickname is still the "garlic Marasmius".

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

Gymnopus and Collybiopsis (Marasmiellus) - click to expand

The main genera for many collybioid mushrooms (white spores, slender stature and never that large, possible tough stem, attached gills that aren't usually decurrent). Some marasmioid mushrooms are found here too (even smaller size, distant gills, dark stem bottoms). Some of the collybioids smell of garlic and will be confused with Mycetinis and Paragymnopus, below, which are smaller marasmioids. Uniting these two genera (and making them hard to tell apart) is the fact that although they have typical repent, filamentous hyphae in the cap cuticle (and not spherical cells) the hyphae are often knobby or branched with interesting outgrowths. There is no good way to tell the two genera apart, although it seems to me more Collybiopsis species have pubescent stems and more Gymnopus have bald stems.

Species mentioned: Gymnopus dryophilus, aquosus, alpinus, junquilleus, subsulphureus, ocior, earleae, vernus, erythropus, spongiosus, fuscopurpureus, alkalivirens, brassicolens, dysodes, barbipes, impudicus, polyphyllus, putillus, fusipes, contrarius, quinaultii, striatipes. Marasmius androsaceus. Collybiopsis peronata, confluens, confluens subsp. campanulatus, bakerensis, luxurians, subpruinosus, villosipes, eneficola, hasanskyensis, californica, pluvius, vaillantii. Marasmiellus papillatus, filopes. Microomphale arbuticola.
Species no longer found in Marasmiellus: M. candidus (see Marasmiaceae)

Mycetinis - click to expand

Garlic odors - smaller marasmioid mushrooms than the garlic Gymnopi, and with two-toned black bottomed stems. Similar to Paragymnopus which have rotten cabbage odors, but Mycetinis has spherical cap cuticle cells and perhaps stems thicker than 1mm.

Species mentioned: Mycetinis scorodonius, scorodonius forma diminutivus, allaceus, salalis, copelandii, applanatipes

Paragymnopus - click to expand

May have a rotten cabbage odor, and stems <1mm thick, but recent studies are showing that they also may not, making their identification more difficult than we thought. They are small, brownish capped marasmioid mushrooms with tri-coloured stems that are black on the bottom. When strongly odiferous, they are most similar to Mycetinis, but those have odors more consistenly described as garlic instead of rotten cabbage, although the odors are similar. Mycetinis can easily be differentiated microscopically by a spherical cap cuticle. The small Collybiopsis like C. californica may have thicker stems <1mm thick. Gymnopus androsaceus (with a blackish wiry stem) and Pseudomarasmius pallidocephalus (with a pale brown cap) are both easily confused with those Paragymnopus that lack the strong odor.

Species mentioned: Paragymnopus perforans, perforans subsp. transatlanticus, ponderosae, pinophilus, sublaccatus, sequoiae, Gymnopus bulliformis, fragillior, glabrosipes

Rhodocollybia, Connopus, Pseudomarasmius, etc. - click to expand

Connopus aff. acervatus (bagleyensis n.p.) is a very tightly clustered burgundy collybioid.

Pseudomarasmius pallidocephalus is a small, pale capped marasmioid with a dark stem that is fairly thin (<1mm thick) but not as wiry as Gymnopus androsaceus. Easily mistaken for small Collybiopsis like C. californica (which might have a thicker stem) and the somewhat darker capped Paragymnopus.

Rhodocollybia are larger and fleshier, with fleshy (not tough) stems that may be long and rooting. The spore print is somewhat coloured. The gill edges are often serrated. Rhodocollybia may need to be split, with at least 'Rhodocollybia' subsulcatipes possibly needing a new genus. 'Gymnopus' striatipes also needs a new genus. The only species guaranteed to stay in Rhodocollybia are the Rhodocollybia maculata group of species. The others clade with that type species with weak support at best.

Species mentioned: Rhodocollybia butyracea, butyracea forma asema, prolixa, badiialba, olivaceogrisea, maculata, oregonensis, unakensis, extuberans, subsulcatipes, Gymnopus striatipes, Collybia cylindrospora

Omphalotus and Lentinula

Not typically found in the PNW, but here for completion.

Omphalotus olivascens CA - the glow in the dark poisonous jack-o-lantern, perhaps found in southern OR.

Lentinula aff. edodes - shiitake, often cultivated here and might escape. Worldwide sequences vary by up to 6%, so I don't know if it's a complex of species or not.


Back to Main Menu