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Danny’s DNA Discoveries – Crepidotus and Simocybe of the PNW
by Danny Miller

Click here for my Pictorial Key to Crepidotus and Simocybe


These two related genera have warm brown spores (not cold dark brown spores) and are found attached to pieces of wood - but that's where the similarity ends. One is a small brown spored oyster mushroom and the other is a obscure, generic LBM.

Crepidotus - being almost always completely stemless makes this genus fairly easy to recognize in the PNW, although in other areas of the world they can have completely normal stems and be very difficult to place in this genus. The caps are almost always whitish or brownish, and usually not hygrophanous. The spores are almost always warty. Most easily confused with the gilled bolete Tapinella panuoides, which has odd gills that either fork, crimp (wiggle) or intervein and possibly start to look like pores near the point of attachment.

Simocybe - true LBMs - small, brown (often olive-brown?), central-stemmed mushrooms (usually cap <2.5 cm) with an overall pruinose (powdery) look and white mycelium at the base of the stem. Usually hygrophanous. Smooth spores. They were never studied in the west, and never reported from the PNW until Key Council members started reporting them around 2010, so very little is known about them so far. Similar genera: Simocybe are typically smaller than Pholiota but easily confused with Galerina and Tubaria. Melanotus (now in Deconica) usually has colder, darker coloured spores and an eccentric stem and is more often found on textiles.

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:

  • reports of Crepidotus mollis actually seem to represent the distinct species Crepidotus calolepis as well as an unnamed species.
  • one of our common species may be the little known Crepidotus occidentalis - Crepidotus were well studied microscopically back in 1965 and we have a microscopic key to morphologic species, but we have little genetic information about most of them and need a modern study to figure out which are unique species and which are synonyms.
  • Simocybe serrulata is our first Simocybe in the PNW confirmed by DNA.



Simocybe serrulata NY (=Simocybe sumptuosa UK) - the only Simocybe confirmed by DNA from the PNW. It may have serrulate (or at least frayed) gill edges. We have more than a dozen matching sequences from back east that are within 1% of each other and ours (a little more variation than the usual 0.5%) that match the unpublished type. Sequences of Simocybe sumptuosa, including the type, also match. That species lacks the serrulate gill edges and is a newer synonym. This species may or may not have serrulate gill edges.

Simocybe serrulata © Yi-Min Wang (2 images)


Simocybe centunculus EU - has shorter spores (6-7.5 x 4-5u versus 7-10 x 4-5.5u). One WA sequence matches one EU sequence, so this may represent the real species.

Simocybe 'haustellaris PNW01' - may have an eccentric stem and has wider spores (8-10 x 5.5-7u versus 7-10 x 4-5.5u). So far we have found a collection matching one possible concept of this EU species, but not matching another. Simocybe rubi EU is probably a newer synonym of the EU species.

Simocybe 'haustellaris CA01' - seems more likely to have barely any stem at all and almost resemble Crepidotus. This is the other possible concept. They are not sister species. It has now been found in ID. We need to figure out which is the real thing, but it may be this one.

Simocybe PNW02 - one WA collection and a few CA collections.

Simocybe PNW03 - one ID collection, 5% different in ITS from S. centunculus.


Simocybe centunculus © Matthew Koons,     S. 'haustellaris PNW01' © Matthew Koons,     S. 'haustellaris CA01' © Ed Barge

Simocybe PNW02 © Harte Singer (from CA) and Danny Miller,     S. PNW03 © Ed Barge



Crepidotaceae PNW04 -This cup fungus appears to be in the Crepidotaceae. It resembles Calyptella.

Crepidotaceae PNW04 © Matthew Koons


DISTINCTIVE SPECIES (hairy species and/or clampless)

Crepidotus calolepis EU (C. mollis misapplied) (=Crepidotus ochraceus OR) - with a gelatinous, peelable cap cuticle. No clamp connections and often with lots of brown hairs on the cap (most other species have a smooth cap). We have been erroneously calling this Crepidotus mollis for years. The error happened because Hesler and Smith placed more emphasis on microscopic differences than macroscopic ones, and they considered Crepidotus mollis (smooth to almost smooth-capped) and Crepidotus mollis var. calolepis (with many brown hairs) to be the same thing, as they were microscopically very similar, even though they looked very different. Since the hairy capped C. calolepis used to be a variety of C. mollis, they used the name C. mollis for both of them. So that's how our PNW collections of C. calolepis started being erroneously called C. mollis. It is now widely accepted that the two species are different and the genetics bears that out as they are quite distinct, and our DNA matches C. calolepis and not C. mollis. Ironically, if you use North American guidebooks, which usually repeat H&S' error, our mushroom will key out incorrectly to C. mollis, but if you use a European guidebook (which you're not supposed to do) where they acknowledge both species, you would key out to the correct species.

Crepidotus ochraceus OR was described from a single collection, differing by having a smooth cap instead of a hairy one. The type sequence is the same as C. calolepis, so it was an aberrant collection. This is a cautionary tale against describing a species from a single collection.

Crepidotus fraxinicola NY - with subtler (or no) hairs, but still with a peelable cap cuticle, differing by a lack of incrustations on the brown hyphae of the cap surface. East coast type area sequences differ from PNW sequences from 4-6 bp. There is no known way to differentiate east coast from local collections yet, but it is possible that our collections need a new name.

Crepidotus sububer ID - like C. calolepis but with the gelatin extending a bit deeper into the cap. We'll need a type sequence or other collections to sequence to find out if this is really a distinct species.

Crepidotus mollis var. cystidiosus WA - like C. calolepis but with pleurocystidia. We'll need a type sequence or other collections to sequence to find out if this deserves recognition as a distinct variety or species. If so, it will need a new name.

Crepidotus calolepis © Yi-Min Wang,     C. fraxinicola © Buck McAdoo


Crepidotus crocophyllus OH - our other distinctly hairy brown species, lacking a gelatinous cap cuticle, this is the most colourful species we have, with yellow-orange cap and young gills. It has round spores. If the colours have faded, it can still be recognized by a bright orange KOH reaction. East coast sequences all differ from each other by 5 bp or so (a little less than 1%), and our two local sequences differ from each other by 1%, so there's some genetic variation in this species, but for now I'm assuming it's all one species.

Crepidotus crocophyllus © Richard Morrison


Crepidotus 'epibryus PNW01'  - somewhat easy to recognize with a paler brown spore deposit than the other species, and a usually small (<2 cm) white cap that is usually rounder than other species' caps. The spores are often somewhat spindle shaped (fatter in the middle) or pip shaped (pointy on one end but round on the other like an apple seed). Clampless. Our two BC sequences that match each other are nothing like EU sequences claiming to be C. epibryus. C. herbarum NY and C. pubescens EU are similar species reported from the PNW, but some think they are both the same as C. epibryus. A second species could be here, because Hesler and Smith reported collections with a different spore size and shape that they called C. pubescens, so even though most folks now think their concept of C. pubescens is the same as C. epibryus, I would like collections with both spore sizes to verify how many species we have.

Crepidotus CA01 - this lookalike is actually a close relative of C. epibryus.

Crepidotus subverrucisporus var. megalosporus CO (=Crepidotus hamulatus MI?) -two EU sequences with this name suggest that C. subverrucisporus is related to the real C. epibryus, but not C. 'epibryus PNW01'. The species has often been mistaken for C. epibryus, as it is also a small, round, white capped species. Two WA sequenced collections that are in this part of the tree are small and round and have the very large spores of var. megalosporus. These sequences also match well with the type sequence of C. hamulatus.

Smith described C. hamulatus MI from a single collection.. He said it was distinct from C. subverrucisporus based on the fact that it was not white when young. His single collection could have been old and pigmented. There's no way he knew that it wasn't white when young. In our two collections, one is young and white, one is older and brown. They are exactly the same sequence in ITS1, and differ by 2 characters in ITS, one near the end. This shows the same genetic species probably can be white or brown at different stages, taking away Smith's sole reason for considering C. hamulatus a separate species. The size of C. hamulatus' spores are in between those of var. subverrucisporus and var. megalosporus. Also, both var. roseifolius and var. megalosporus have pink gills, but differ in spore size. None of the characters of gill colour, spore size, or cap colour seem to be informative by themselves, but intergrade. I think it's reasonable to assume C. hamulatus is a newer synonym of something in the C. subverrucisporus complex. If our local varieties turn out to need to be raised to species level from C. subverrucisporus, then we could use the name C. hamulatus. We still won't know that even after the types of our local varieties are sequenced, without an EU type sequence of the type variety.

Crepidotus subverrucisporus var. subverrucisporus EU/var. roseifolius MI - Both the EU type variety and a MI variety roseifolius are reported from OR. They should still be looked for. They have smaller spores than var. megalosporus, but one has pinkish gills. As discussed above, they may all be the same thing.

unsequenced Crepidotus 'epibryus PNW01' © Christian Schwarz,     C. CA01 © Daniel Morton,     C. subverrucisporus var. megalosporus © Yi-Min Wang (2 images)


Crepidotus cf versutus NY - dry, white hairy cap (white hairs), no clamp connections and large elliptical spores (7-11u long). Hesler and Smith never found this species in the PNW, but others have since reported it in BC, WA and ID. It's distinctive, so if it's here and not that rare, how did H&S miss it? We need sequences to see if this is really what people are finding, but we don't yet have any ITS sequences of this east coast species to compare to (but some LSU sequences suggest it is related to C. epibryus).


ROUND SPORED SPECIES WITH CLAMPS (C. crocophyllus has been discussed above)

Crepidotus applanatus var. applanatus EU - white cap, round spores <= 5u, with thinner individual gills than C. malachius?

Crepidotus applanataus var. globiger EU - similar, but with round spores >5u. All our collections have intermediate sized spores, 5-5.5u in diameter. They all have the same ITS. I doubt that this variety has distinct ITS from the type variety, and it doesn't seem that it is a real distinct variety.

Crepidotus stipitatus MI - we found a collection of Crepidotus applanatus once with a tiny, stubby stem near Mt. Rainier in WA. It sequenced the same as C. applanatus. But as it had a tiny stem, it looked like it might be C. stipitatus, one of the only species described with any sort of a stem. However, since C. applanatus can have a "short, white plug" for a stem, and C. stipitatus is described with a stem only 2-3 mm long, and as under the scope they look pretty much the same, either C. stipitatus is not a distinct species or if it is, it is not found in the PNW.

Crepidotus malachius var. trichifer WA - white cap, round spores > 5u with thicker individual gills than C. applanatus? Originally called var. trichiferus. Crepidotus malachius is an old Fries species, which usually are from Europe, but this was one of the exceptions that may have been based on a New England description. We only have EU sequences, not ENA sequences, but I am assuming they represent the real thing. C. malachius var. trichifer varies microscopically from the type variety and was described from WA, but we need collections and sequences to see if it is the same as the type variety, deserves its status as a distinct variety, or should be a separate species. Preliminary sequence data suggests it is a distinct species, not a variety of C. malachius.

Crepidotus subsphaerosporus EU (=variabilis var. subsphaerosporus, =cesatii var. subsphaerosporus) - reported from WA and ID, this is another white capped roundish spored species, perhaps not as perfectly round spored as the others, although the round spored species don't appear to clade together, so that may not have much genetic meaning. We don't have any sequences of this at all, although we do have EU sequences of the type varieties of C. variabilis and C. cesatii, which do not have round spores, and therefore probably are not the same as this variety, even though some have synonymized them.

Crepidotus applanatus © Danny Miller,     with a short stem © NAMA and the Field Museum of Natural History


Crepidotus contortus WA - brownish cap (not white like the above), round punctate spores, narrow gills, contorted cheilocystidia. No sequences from anywhere yet, we need collections.

Crepidotus pallidobrunneus MI - also a brownish cap, round punctate spores , broad gills, "normal" cheilocystidia, reported by H&S from OR. No sequences from anywhere yet, we need collections.


ELLIPTICAL SPORED SPECIES WITH CLAMPS (C. epibryus has been addressed above)

Crepidotus cf lundellii EU - we have many EU sequences, but no local sequences to compare to yet to make sure ours is the same thing. It is reported very often in the PNW and said to be quite common, so it's suspicious that I haven't run across it yet. It has smooth, elliptical spores, or at least warts that are smaller and harder to find than other species.

Crepidotus amygdalosporus EU - similar, with warty, elliptical spores, it was formerly considered a separate species, but is now considered a synonym of Crepidotus lundellii because the former may actual have warts, they may just be harder to find. We don't have any sequences from anywhere, though, to confirm the synonymy.

Crepidotus circinatus WA - three WA and 1 OR sequence match an isotype sequence of Crepidotus circinatus, which has slightly roughened spores 6-8x4.5-6u. Crepidotus spore ornamentation is very hard to see, requiring a high quality oil immersion lens, so whether or not spores have some kind of ornamentation is not consistently reported.

Crepidotus ellipsoideus MI (+ID) - we have the type sequence and it is close to C. circinatus. It was invalidly published as there was no accompanying illustration so it may have to be redescribed.

Crepidotus variabilis var. trichocystis MI - Smith described this from MI and ID, with smaller slightly roughened spores, and we have a sequence of one of his original ID collections. It is >6% different than EU sequences of the type variety, so perhaps it will need its own species name someday, especially if other species are discovered in between them (but I don't know of any so far). It is also reported from BC. We have one sequenced collection from CA, but they are very immature, small, white fruitbodies.

Crepidotus PNW02 - we still need to figure out which non-round spored species this keys out to, but interestingly, it's ITS DNA is not within 15% of any other species we've sequenced so far.

Crepidotus PNW03 - this seems to be in the same section as PNW02, separate from the others. Our collections are small and white and circular, but the spores are too dark to be C. epibryus.

Crepidotus fimbriatus ID/Crepidotus lanuginosus ID - separated among other things by the unreliable character of whether or not the cap is white at first when young, and a few subtle microscopic differences. We now have type sequences, and they are very close together and probably synonyms. We have a photo of a collection that keyed out to this from perhaps CA, but that wasn't sequenced.

Crepidotus obscurus MI/fusisporus MI +WA (+var. simplex MI +OR) - we have the type sequence of C. fusisporus var. simplex, plus non-local varieties var. rameus and var. anomalus, but not the type variety sequence. They match each other and the holotype sequence of the older species Crepidotus obscurus MI within a couple bp.

Crepidotus circinatus © Fred Rhoades (2 images),     C. PNW02 © Yi-Min Wang (2 images)

Crepidotus PNW03 © Vail Paterson,     C. obscurus/fusisporus © Sandra Ruffner


Locally described - these species, all differentiated only microscopically, do not have round spores (nor any gelatin in the cap cuticle, nor any coloured hairs on the cap). They must exist here, as they were described either locally or using material from the PNW as supporting collections. However, we know nothing about them. We need type sequences, or new collections that key out to them to start to figure out what they are, and which of them are duplicates of each other or something else.

Crepidotus cinnamomeus ID

Crepidotus lagenicystis WA

Crepidotus occidentalis WA - very similar to C. circinatus, but smooth spored.

Crepidotus payettensis ID

Crepidotus pseudoflammeus WA

Crepidotus rainierensis WA - the type has the same sequence as the types of C. brunnescens, C. avellaneus, C. obfuscens, and C. campylus. All 5 are from 1965. No recent photographed sequenced collections.

Crepidotus regularis MI +WA, OR, ID - we have the MI type sequence, but need local sequences.

Crepidotus stratosus ID - loosely interwoven cap cuticle hyphae on top of tightly interwoven hyphae (unique in the genus in the PNW), long cheilocystidia and large spores.

Crepidotus submollis WA +OR,BC

Crepidotus villosus MI +WA,ID

Crepidotus vulgaris MI +WA


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