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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 (usually not hygrophanous). The caps are almost always whitish or brownish. 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.

Click here to download the FASTA data of all my DNA sequences

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 - the only Simocybe confirmed by DNA from the PNW. It has serrulate 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%). A couple sequences of Simocybe sumptuosa, said to be almost identical except for a lack of serrulate gill edges (and considered a synonym by some), fall within the same clade and are difficult but not impossible to distinguish by ITS DNA. Assuming these sequences are correctly labeled, it remains to be seen if the species will be considered the same or separated by gill serration.

Simocybe serrulata © Yi-Min Wang


The following species have been also been reported or rumoured, at least once, from the PNW, but we don't have any sequences yet to give an accurate picture. Collect all of them that you can find.

Simocybe centunculus EU

Simocybe rubi EU (=haustellaris?)

Simocybe sumptuosa UK - as noted above, some say this is a synonym of Simocybe serrulata. We need local sequences of collections without gill serration to study.

Simocybe cf centunculus © Danny Miller,     Simocybe cf haustellaris and cf sumptuosa © A and O Ceska



Crepidotus calolepis EU ('mollis') - easily recognized by 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 EU 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 accepted by everyone 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 a North American guidebook, 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. Hesler and Smith described Crepidotus sububer ID as having gelatin extending a bit deeper into the cap, but we'll need a type sequence or other collections to sequence to find out if it's really a distinct species, or one of the below mentioned species, or what. Crepidotus mollis var. cystidiosus WA was described locally as the only species to have pleurocystidia, so we will need to sequence it to see if it is indeed genetically different.

Crepidotus aff mollis - a couple of WA sequences, presumably with sparser brown hairs (or maybe even none, but always with a peelable cap like C. calolepis), are a different species. We'll need more collections to figure out how to tell them apart for sure, as the scales can wash off C. calolepis. The sequences don't quite match either Crepidotus mollis nor the similar Crepidotus fraxinicola NY (said to differ by not having incrustations on the cap hairs, and its status as a unique species seems to be born out genetically as some east coast sequences are unique). C. fraxinicola was reported from the PNW, so we should keep looking for it. One possible identity of C. aff mollis is Crepidotus ochraceus OR, said to have a total lack of brown pigment in any hairs on the cap, and as it was described locally, it definitely occurs here, but we need sequences to see if it is a synonym of something older, and if it is this species or something different.

Crepidotus calolepis and aff. mollis © NAMA and the Field Museum of Natural History, Buck McAdoo


Crepidotus crocophyllus OH - our other distinctly hairy species, this is the most colourful species we have, with yellow-orange cap and young gills, the cap covered in brown hairs. 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.

Crepidotus crocophyllus © Richard Morrison


Crepidotus cf epibryus EU - 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). Our one purported BC sequence is not the same as a few European or other American sequences, but I don't have a lot of confidence in any of the IDs, so I'm not drawing any conclusions yet. The real C. epibryus is said to have clamp connections. I don't know if the locally photographed sequenced collections do.

Similar clampless species with spindle/pip shaped spores have also been described and reported from the PNW, including Crepidotus herbarum NY and Crepidotus pubescens EU. (which some say should now be called Crepidotus bresadolae and others say is the same as C. epibryus. However, others say C. pubescens is the same as C. versutus, below, so the picture is still quite confusing). We need more collections from here and around the world to see if we have more than one genetic species here, or if not, what the proper name is for the one we do have, as we don't have any sequences anywhere yet of C. herbarum, C. pubescens or C. bresadolae. The importance of clamp connections to species also needs investigating.

Crepidotus cf epibryus © Christian Schwarz


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). Although the spore size appears to be way off, some have suggested Crepidotus pubescens is a synonym of this and not Crepidotus epibryus, so that has to be worked out.



Crepidotus 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. We have ITS DNA from WA of this variety, and ITS DNA of collections of unknown variety, but I need collections of the type variety to see if there is a distinct ITS difference between varieties or not.

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, the situation is confusing. I have my doubts that our collection was anything other than C. applanatus. There are no sequences of C. stipitatus ever made for us to know what that species is genetically, so once we get them, we'll have to see if the ITS region is the same as C. applanatus or not. Until then, I am assuming C. stipitatus 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.

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, round spores, narrow gills, contorted cheilocystidia. No sequences from anywhere yet, we need collections.

Crepidotus pallidobrunneus MI - brownish cap, round 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, but it is reported very often in the PNW and said to be quite common, so I'm eager to get collections and check them out. 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 - two WA and 1 OR sequence match an isotype sequence of Crepidotus circinatus, which has large slightly roughened spores. 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 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.

Crepidotus sp. 148 - 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 circinatus (as occidentalis) © Fred Rhoades,     C. sp. 148 © Yi-Min Wang


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 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 ellipsoideus MI (+ID) - invalidly published as there was no accompanying illustration, so if it is a real, distinct species, it may have to be redescribed.

Crepidotus fimbriatus ID - we have a photo of a collection that keyed out to this from perhaps CA, but no DNA.

Crepidotus fusisporus MI +WA (+var. simplex MI +OR)

Crepidotus lagenicystis WA

Crepidotus lanuginosus ID

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

Crepidotus payettensis ID

Crepidotus pseudoflammeus WA

Crepidotus rainierensis WA

Crepidotus regularis MI +WA, OR, ID

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 subverrucisporus EU +OR (+ var. roseifolius MI + OR) - one collection from BC keyed out to the type variety, but no DNA yet.

Crepidotus villosus MI +WA,ID

Crepidotus vulgaris MI +WA


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