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Danny’s DNA Discoveries – Tricholoma of the PNW
by Danny Miller

Click here for my Pictorial Key to Tricholoma


Medium to large mushrooms (2.5-15+cm, but even the small ones are rather stocky). White spores and usually notched gills. Non-hygrophanous opaque cap that is sometimes scaly. Found on the ground. Dry or viscid cap, partial veil or not. (Mushrooms <5cm with a scaly/shaggy stem, or >5cm with a shaggy stem may be on the Lepiota page).

Thanks to a recent paper by Steve Trudell et. al, they are well studied in the PNW. We don't have names for everything yet, but we have a lot of data.

Click here to download the Trudell et. al. Tricholoma paper

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
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A veil or ring is unusual, and will be noted, if present, in the heading. The differentiating characters will be the presence of a veil, a viscid vs. dry cap, the odor/taste, and whether or not the cap texture is best characterized as scaly or streaky or neither.


Soapy Trich - Trudell clade 2

Tricholoma 'saponaceum' EU group - this group of very variable species has a lot of lookalikes, so the best thing to do when identifying a Tricholoma is to first consider if you have something in the T. saponaceum group before proceeding. The dry caps are usually grey (strongly resembling T. 'virgatum', nigrum etc.), but may be yellow, yellow-green or sometimes even brown, like so many others. The odor and taste is usually "soapy" and the very, very bottom of the stems (dig it all up carefully) usually have a splash of pink.  We do not appear to have the EU species, if everybody's best guess as to what the real sequences are is correct, but we have 5 sister species:

Tricholoma 'saponaceum PNW01' - sequenced once on Vancouver Island BC. I do not have a photograph.

Tricholoma 'saponaceum PNW02' -sequenced a half dozen times.

Tricholoma 'saponaceum CA01' - sequenced twice in BC and once in OR. Also in CA.

Tricholoma 'saponaceum PNW04' - sequenced once in eastern WA.

Tricholoma 'saponaceum PNW05' - while the others so far seem to be grey to dark grey capped, this one was pale olive-yellow-brown capped. The stem and gill edges stained red-brown in age quite clearly. It was sequenced from WA, NBC and a couple times in CO.

One species may have a scaly stem, keep an eye out for that one.

Tricholoma subluridum OR - described in vague terms from OR from a single collection of a white mushroom with black on the disc. Usually when you find one mushroom that looks different, and never see it again, it's because that mushroom was atypical. Later microscopic studies suggested it might be one of the members of the T. saponaceum complex. Without a type sequence, we'll never know, and we'll have to continue ignoring it.

Tricholoma 'saponaceum PNW02' © Danny Miller,     T. 'saponaceum CA01' © NAMA and the Field Museum of Natural History,     T. 'saponaceum PNW04' © Andrew Parker

Tricholoma 'saponaceum PNW05' © Kendra Dedinsky (3 images)


Matsutake -veiled, white with brown, matsutake odor, not truly viscid - clade 6

Tricholoma murrillianum OR - our Matsutake, formerly called Tricholoma magnivelare, but that is a distinct east coast species. Make sure you know how to tell it apart from the deadly lookalike, Amanita smithiana.

Tricholoma anatolicum Turkey - inside a soil sample from pine roots in the Oregon Dunes NRA they found a sequence of the Turkish Matsutake, so perhaps it is to be looked for here. Here's more information. It supposedly only grows with lebanese cedar (Cedrus libani), though, whereas the original T. matsutake, differing by 1%, grows with pine. What does this mean? The Turkish Matsutake supposedly has a more cedar-like odor, the gills don't spot brown in age and has slightly more elliptic spores?

Tricholoma dulciolens EU - long mistakenly called Tricholoma caligatum, this species has darker brown colours and a slight bitter taste. Way back in 1989 they discovered a lookalike of T. caligatum in Europe, T. ducliolens, but in the 30 years since nobody over here thought to check if our T. caligatum might be that instead. It took DNA sequencing to find out.

Tricholoma murrillianum © Steve Trudell,     T. dulciolens © Danny Miller


Veiled, orange-brown to brown, farinaceous, not truly viscid - clade 3a-I

Tricholoma focale EU (=T. zelleri WA) - well developed veil, bright orange colours. Very farinaceous. The type sequence of T. zelleri matches T. focale's type sequence and they are now officially synonyms.

Tricholoma badicephalum OR - also strongly veiled, lacking orange (pale to dark brown) formerly in Armillaria, this is the similar species we had mistakenly been calling Tricholoma robustum EU. The type sequence failed, so a new type was designated.

Tricholoma focale © NAMA and the Field Museum of Natural History,     T. badicephalum © Danny Miller (darker brown version)


Veiled, strong cucumber odor, dry caps, spring - clade 14

Tricholoma vernaticum CA - a quite large, spring fruiter with a veil, a white or brown cap, and an especially cucumber-like farinaceous odor.  A few OR sequences match the CA type fairly well.

probable Tricholoma vernaticum © Andrew Parker


Bright orange-brown, no veil but a well marked ring zone above a scaly stem. Viscid, farinaceous - clade 3a-I

Tricholoma aurantium EU - strong orange scales below a well defined "ring zone" make it look like it once had a veil. Very farinaceous. Our sequences are 2 bp and 2 indels different from EU sequences, but no differences have been noted yet so I assume it's the same species.

probable Tricholoma aurantium © Michael Beug


Sweet odor, dry white caps, maybe turning yellow - clade 8

Tricholoma 'stiparophyllum AK01' - a slender all white Tricholoma said to have an unpleasant sickly-sweet odor. Our 1 WA and 1 AK collections may be a sister species to the EU species, averaging 4 bp and 7 indels different from more than a hundred EU sequences.

Tricholoma farinaceum WA is a slender, strongly farinaceous white mushroom described from Seattle, but nobody knows what it is (the current thinking is it's probably not even a Tricholoma, but I had to talk about it somewhere so I'm talking about it now). Multiple attempts to sequence the type failed to find out. Its description says it has round spores but a re-studying of the type showed that they are actually 4-6 x 2-3.5u. Murrill has described species with round spores before (like T. dryophilum) that turned out to have elliptic spores.

Tricholoma lutescens WA - being newly described as our local species long mistakenly called T. sulphurescens. It is of typical Tricholoma stature, not slender, mostly white but turning yellow where handled or in age and smells like coconut.

Tricholoma 'stiparophyllum AK01'  © Buck McAdoo,     Tricholoma lutescens © Andrew Parker


Coal tar odor, dry white-yellow caps - clade 7

Tricholoma platyphyllum WA (=T. inamoenum EU?) - usually white but may be pale yellow. T. inamoenum and T. platyphyllum can barely be told apart by ITS. Only 2 bp distinguish them, but both have sequences that can vary by 2 bp, just not the same bp that distinguish them. A maximum likelihood tree making algorithm says there's a better than even chance that they are 2 distinct clades. That still doesn't mean they are distinct species, but the other differences are slight. Perhaps T. inamoenum is associated with spruce only and T. platyphullum may or may not grow with spruce. For now, we are using our own local name, T. platyphyllum, for PNW collections. T. inamoenum has for sure been found in boreal areas like northern BC and Alaska, but not yet further south. The east coast Tricholoma silvaticum NY is an older name, and if it and T. platyphullum are the same, that name should be used. We need east coast sequences to find out. However, T. inamoenum is the oldest name of all, so if they are the same, that name should be used.

Tricholoma 'bryogenum PNW16' - dull yellow all over like T. platyphyllum can be, or  perhaps bright yellow with a tan cap like T. 'sulphureum PNW06'. The EU Tricholoma bryogenum is a sister species with a dull yellow cap, with white basal mycelium and associated with spruce. We don't know how to tell PNW16 apart from pale yellow collections of T. platyphyllum.

Tricholoma odorum DC - another yellow species (fading to buff) reported from the PNW, but we don't know what it really is. Perhaps one of the unnamed species in this group will turn out to have this name. If not, we have to figure out what it really is and if it does occur in the PNW.

Tricholoma 'sulphureum PNW06' - brown cap, but bright yellow elsewhere, mistakenly called Tricholoma bufonium EU in the past. Nobody knows what the real Tricholoma sulphureum is in Europe, but this is a sister species to possibility number 3. In the EU there doesn't seem to be genetic significance in whether or not the cap is yellow or brown.

We still need sequences of local collections that are bright yellow everywhere to find out what they are. Perhaps, like in the EU, cap colour is not important, and they will turn out to be PNW06, but perhaps not.

Tricholoma platyphyllum © Buck McAdoo,     T. 'bryogenum PNW16' © Jonathan Frank and Steve Trudell,     T. 'sulphureum PNW06' © Noah Siegel


Celery odor, dry cap - clade 5

Tricholoma apium EU - unique celery odor, but also a particular shade of pale brown cap. although local sequences differ by about 5 bp and 1 indel from EU sequences, no ecological or morphological differences have been found and for now the new paper is considering our species to be the same.

Tricholoma apium © Eric Chandler


Dry grey or yellow (possibly umbonate) caps (with radial streaks more typical than scales), acrid taste (odor not strongly farinaceous) - clade 1a-I

Tricholoma subacutum NY (=T. argenteum MI, =T. virgatum var. vinaceum ID) - dry, streaky grey cap (perhaps with some scales, which would make it harder to recognize) and bitter and peppery taste (its most reliable trait) - not quite like Russula, but like "being pricked by tiny needles at tip of tongue". With conifers.

It has long been called Tricholoma virgatum EU, which only differs by 2-3 bp and 2 indels in ITS1 only (ITS2 is identical), but since we have a name for North American collections, we're using it. Since all NA collections sequence almost exactly the same, it is thought that all the NA names represent the same thing, with T. subacutum being the oldest name. This is a perfect example of wondering whether or not two things are the same species or not, and this comes up a lot in Tricholoma. There's not a lot of genetic difference between T. virgatum and T. subacutum/argenteum, ITS2 doesn't even differ at all, but the differences between continents are clear. This means they separated a long time ago and have mutated independently without the populations interbreeding. But mutated enough to be considered a different species? Mycologists disagree. Some compared them and decided no - and T. subacutum was declared a synonym of T. virgatum. But later, Ovrebo took another look and decided that over here the mushroom was usually a little paler, or the cap a little less pointy, maybe with fewer streaks, and decided the species were probably different. (One local photo shows some scales and not a lot of streaking, so I believe this to be true). So what's the answer? The answer is T. subacutum is definitely a good name for our species, but depending on your point of view, T. virgatum might also be a good name and maybe even a better name since it's older. I'll tell you one thing: if our local mushroom didn't already have its own name, the genetic and morphological differences would probably have been too slight for the Trudell et. al. paper to give it its own name (they described new species only when the genetic differences were clearer). But because it already has its own name, and previous mycologists like Ovrebo saw differences between them before DNA studies came along, for now, it gets to keep its own name. Tricholoma acre (acris) MA is a similar hardwood species rumoured to be here but almost certainly not.

Tricholoma aestuans EU - this species shares the same usually dry cap and bitter/peppery taste of T. subacutum (virgatum) and is closely related to it. It has yellow to yellow-green tones in the cap and gills (along with the grey streaks like T. subacutum) and little odor. It was not known from the PNW until sequenced once from OR, 3 bp different from the type sequence. This may have been overlooked before because it looks much like the much more common T. atrofibrillosum, below, which is viscid and has a farinaceous smell and taste.

Tricholoma subacutum © NAMA and the Field Museum of Natural History,     probable T. aestuans © Noah Siegel


Dry grey or yellowish caps (with radial streaks more typical than scales), farinaceous - clade 10

Tricholoma nigrum OR - dry, grey cap like T. subacutum (but not as pointy or streaky?) and strongly farinaceous instead of bitter/acrid. We now have the type sequence, and it is way more common than previously thought. It had usually been identified as T. virgatum (subacutum) without noting the difference in taste. Does this species spot yellow? Keep reading, and also see clades 1c and 12.

Tricholoma cf luteomaculosum MI - a similar grey mushroom, but with cap and gills that might spot yellow. The paper provides reliable sequences from CA. Shanks says it is found in the PNW too, but we need genetic proof. Many local collections called this turned out to be T. nigrum instead, so does that species also spot yellow? Not necessarily, they might not have known about T. nigrum and made assumptions. We need to sequence dry capped collections that spot yellow (note that the viscid T. portentosum group does).

Tricholoma arvernense EU - dry yellow to yellow-brown cap, white gills but some yellowing near the edge of the gills is usually observed. Weakly farinaceous. Not viscid like the T. equestre group. Some OR and ID sequences are within 1-3 bp of reliable EU sequences.

Tricholoma davisiae ME - dry, yellow to yellow-green (pointier?) cap. Usually whitish elsewhere. BC, WA and ID sequences match a Quebec sequence of this east coast species quite well.

Tricholoma nigrum © Sandy Patton,     T. arvernense and T. davisiae © NAMA and the Field Museum of Natural History


similar, pointier cap? - clade 1c

Tricholoma megalophaeum CA - being newly described with coastal spruce from WA and CA, this dry, streaky, pointy capped somewhat farinaceous grey mushroom with yellow tones resembles T. nigrum (and the different tasting T. 'virgatum' and others) so much that it wasn't discovered until sequenced. You'll have to keep this in mind if you're near coastal spruce. It is a sister species to the paler Tricholoma guldeniae EU of Europe. Also see clade 12.

Tricholoma megalophaeum © Noah Siegel


Viscid grey, farinaceous? - clade 1a-II

Tricholoma portentosum EU complex (incl. T. griseoviolaceum CA) - smooth, viscid grey cap. Yellow tones are sometimes found on the fruitbody.

The type sequences of T. portentosum and T. griseoviolaceum are 3 bp, 2 indels and 1 ambiguous location from each other, but ITS does not separate sequences of the two cleanly into two groups. Some sequences in the complex are as much as 8bp different from others in ITS. I am considering this a possible complex of species that additional genes will be needed to sort out (ITS alone can't do it), as there are sometimes distinct differences between collections (and the descriptions of the two above named species) that seem to indicate more than one species could be in this complex.

Also see clade 12 below for some rare lookalikes that are pale grey and only thinly viscid at most.

Tricholoma portentosum complex members © Daniel Winkler, and NAMA and the Field Museum of Natural History (2 images)


Viscid, yellowish cap and gills, farinaceous - clade 1b

Tricholoma equestre EU group - that species (also called Tricholoma flavovirens EU) isn't found here (which is probably good news since this popular edible has killed people in Europe) but the following related lookalikes are. They have yellow everywhere (including the gills), a viscid cap and a slight farinaceous odor (not an odd coal tar odor). See elsewhere for a dry cap.

Tricholoma 'ulvinenii PNW07' EU - this may be our conifer species. There are 2 competing sequences in the EU for T. ulvinenii, and we have 7 sequences from OR, 6 from BC and 1 from CA that match Clausen's first sequence within 5 bp or so and his second sequence within 8 bp or so. So perhaps T. ulvinenii is one of our species. If not, it needs a new name.

Tricholoma frondosae EU - this may be our common hardwood species (the collections with tree data are from mixed woods). In the EU it may get grey scales in age, but that hasn't been observed here. There are also 2 competing sequences in the EU for T. frondosae, and Clausen says this one is "almost certainly" the real one. Our 3 sequences from WA, 2 from OR and bunch from AK are within 3-4 bp. So perhaps T. frondosae. If not, it needs a new name.

Tricholoma yatesii CA - an oak species from CA, now found once under oak in WA. Ours matches a sequence from the type area in CA that seems to be this species.

Tricholoma PNW08 (TR048) - this is a sister species to the other possible T. frondosae sequence of Europe (the one not "almost certain" to be the right one). It was sequenced once from WA (conifers) and a similar sequence was found in AZ (mixed woods). It definitely needs a name.


There has been one vague report of Tricholoma joachimii from this clade in the PNW (as well as Tricholoma fumosoluteum from an unknown clade) but this study failed to turn them up so their existence is doubtful.

Tricholoma 'ulvinenii PNW07' © Steve Trudell,     Tricholoma frondosae © NAMA and the Field Museum of Natural History,     T. yatesii © Michael Beug


Viscid yellow to yellow-brown cap, white elsewhere, farinaceous - clade 1b

Tricholoma 'intermedium PNW17' - similar viscid cap and farinaceous odor, but the gills are white. Only the cap and probably the stem have yellow but can also be brownish. We don't have NY type area sequences, but a collection from EWA and interior BC look like it and could represent sequences of this species. We need east coast DNA to confirm, but this is one guess as to what T. intermedium is. The local species Tricholoma leucophyllum ID is said to be a newer synonym but see below.

Tricholoma 'leucophyllum PNW18' - one Vancouver Island BC sequence of this was named T. leucophyllum. That is supposedly a synonym of T. intermedium, but given that we have at least 2 undescribed species in this group, we should see if that Idaho name can be used for one of them, maybe even this one. Our photo shows it has a more decorated stem than T. 'intermedium PNW17'.

Tricholoma PNW09a/b/c - three OR sequences appear to be three separate sister species (one sequence may be dirty, so maybe there are only 2 species), but with only 1 sequence of each, I hesitate to say that any of these are legit species until we find more collections. They were all identified as T. flavovirens, so maybe they had yellow gills and looked like members of the T. equestre group, above.

Tricholoma 'intermedium PNW17' © Andrew Parker,     T. 'leucophyllum PNW18' © Danny Miller and Steve Trudell et. al,     T. PNW09b #2 © Jonathan Frank


Viscid yellow cap with black streaks - clade 1a-III

Tricholoma atrofibrillosum AK - being newly described as our local species that has been long mistakenly called T. sejunctum EU (with paler fibrils and with deciduous trees and found only in Europe) or T. subsejunctum (almost identical to our species but found only on the east coast). Black radiating fibrils over a viscid yellow cap (the yellow sometimes well hidden by the black fibrils). Also farinaceous.

Tricholoma subluteum NY - a close relative with one vague report of it possibly being in the PNW. We have reliable ENA sequences now, and that DNA has never been found here, so it probably isn't here.

Tricholoma atrofibrillosum © Eric Chandler


Dry brown caps, slightly farinaceous? - clade 3b

The stem apex is usually white in this clade, but often coloured below.

Tricholoma 'imbricatum PNW10' - cap not scaly. Conifers. Slightly farinceous. Our common local species is definitely different enough in ITS to be considered a sister species to this EU species that needs a new name.

Tricholoma aurantio-olivaceum WA- Odorless? A related, locally described slender species usually with a more orange tinge to the cap and rusty orange fibrils on the stalk. The cap may be conical and the gills can stain brown.

Tricholoma vaccinum EU - cap usually scaly and stem usually hollow. Conifers. Slightly farinaceous. Many of our sequences do match EU sequences quite well. A couple of AK sequences are about 1% different, and one WA sequence is 1% different from both, so this seems to be a species with somewhat variable ITS. The Tricholoma study found them to probably be conspecific.

Tricholoma 'psammopus PNW11' - very similar, dark brown cap and stem contrasting with bright white gills and a scaly stem (like a dry capped Tricholoma 'stans PNW12' below in clade 3a-II). Two Oregon sequences differ from EU sequences by 2 and 4 bp but perhaps a few more at the end of ITS as well. All the EU sequences cluster closer together than that so ours do stand out a bit. It appears that is enough to make ours a distinct species as the actual EU species is not that dark, but paler and more brightly coloured (orange-brown) with a white stem apex. Unknown from the PNW until the sequences showed up. In the EU it seems to prefer larch, but probably not here, as the one time trees were noted they were Douglas fir.

Also see clade 12.

Tricholoma 'imbricatum PNW10' © Steve Trudell,     T. aurantio-olivaceum © Andrew Parker

Tricholoma vaccinum © Andrew Parker and Yi-Min Wang,     T. 'psammopus PNW11' © Steve Trudell and Tony Trofymow    


Brown, no partial veils. Viscid and farinaceous - clade 3a-II

Tricholoma ammophilum - being newly described as our abundant paler capped hardwood species from sandy habitats near cottonwood. The gills stain red-brown in age and the stem starts out white but turns the colour of the cap in age. It has long mistakenly called Tricholoma populinum.

Tricholoma fulvum EU (=T. nictitans EU, =T. transmutans NY) - our abundant conifer species with yellow tones in the gills or flesh, long mistakenly called Tricholoma pessundatum, with many sequences from all over the PNW matching many EU sequences quite well, differing by at most 2 indels and no base pairs. No morphological or ecological differences have been found, so I think we have this species, even though the new paper has not made that call, perhaps because the tiny DNA differences are consistent. But they're really, really, tiny. The study suggests that Tricholoma transmutans NY may be a synonym. That is supposed to be abundant back east but no collections there sequence differently than T. fulvum.

Tricholoma albobrunneum EU (=Tricholoma muricatum CA?) - a pine conifer species, without yellow tones, from CA but extending into OR, difficult to tell apart from T. fulvum. The type sequence of T. muricatum is only 1 bp and 1 indel different from many EU sequences of the older T. albobrunneum. Two OR sequences are are 2-4 bp different from both, so since all the western NA sequences don't clade together, but are mixed in with both T. muricatum and T. albobrunneum sequences, I tend to believe they are synonymous, although the new paper did not formally synonymize them. It is possible that ITS can't differentiate them, but other genes will. One OR sequence is 6-7 bp different and represents the furthest sequence from the others, but there's only one of them.

Tricholoma subannulatum CA - this CA oak species with a reddish-brown cap was sequenced under WA and OR and BC oak too. We don't have a type, but the paper found sequences they thought were reliable.

Tricholoma dryophilum CA - a microscopically different CA oak species rumoured from the PNW and to be looked for, although so far reports of it have turned out to be T. subannulatum. Reliable CA sequences are only 2 bp and 2 indels from the type sequence of the older Tricholoma stans in Europe, but the differences are consistent, so it is not being considered a synonym yet. Also, T. stans has a scaly stem, but T. dryophilum does not.

Tricholoma 'stans PNW12' - with a somewhat scaly stem, this sister species has shown up in BC a few times and once in WA. I don't know the tree association, this needs to be investigated. It has a positive UV reaction, unlike T. fulvum.

Tricholoma ustale EU - probably does not occur in the PNW. There were only a few rumours, but it has so many lookalikes and now we have reliable EU DNA and nothing from here matches it yet.

Also see clade 12.

Tricholoma ammophilum © Yi-Min Wang (2 images),     T. fulvum © NAMA and the Field Museum of Natural History,     T. subannulatum and T. 'stans PNW12' © Danny Miller


Clade 12 - (currently difficult to ID) thinly viscid, grey or brown caps, farinaceous

Tricholoma mutabile CA - hard to recognize. It is said to be like T. portentosum but paler grey on the cap or grey-brown and only with yellow areas in age. It is probably only thinly viscid when wet because it  has also been mistaken for dry capped species like T. nigrum. We have WA and OR sequences matching the CA type.

Tricholoma 'mutabile PNW19' - one OR sequence is in between Tricholoma mutabile CA and Tricholoma josserandii EU, about 3-4 bp and 2-4 indels from each. We need to see if we can find it again.

Tricholoma marquettense AL - one WA sequence matches something they think represents T. marquettense from Alabama. It is very closely related to T. mutabile and is described almost identically.

Tricholoma subumbrinum WA - yellow-brown disc with a paler rim, white elsewhere but gills staining brown. Long forgotten because nothing was known about it, we now have the WA type sequence and BC and OR sequences match it. It is thinly viscid and has likely been mistaken for similar dry and viscid Tricholomas like T. imbricatum and T. pessundatum.

Tricholoma mutabile © Fred Rhoades and Danny Miller,     T. subumbrinum © Ann Goddard


Clade 4 - viscid, pale pinkish-tan and stocky, odorless

Tricholoma japonicum JP - a viscid, very pale pinkish tan, stocky Tricholoma, probably with conifers. Two WA sequences were found in the recent study that match closely to what they think is the real thing.

Tricholoma manzanitae CA - very similar, but with madrone. A CA species that may be found as far north as Oregon.

Tricholoma japonicum © Noah Siegel


Very black scales (not just grey) on cap and maybe stem - clade 11

There are 2 reported species: Tricholoma atrosquamosum EU with few stem scales and Tricholoma squarrulosum EUwith many stem scales. Some consider the latter to be a variety of the former, but the recent paper seems to settle that they are not varieties of each other, but quite different. But nothing else is settled. We don't yet seem to have either EU species here.

 Tricholoma 'olivaceotinctum PNW13' - based on one eastern WA sequence, our species with a very scaly stem may be a sister species to the EU T. olivaceotinctum, which is a conifer version of the hardwood T. squarrulosum with a greenish tint to the cap sometimes. The real Tricholoma olivaceotinctum is found in northern BC and Alaska, but so far, not here.

Tricholoma 'atrosquamosum PNW14' - our species without many stem scales may be a sister species of T. atrosquamosum, if one OR environmental sequence is to be believed, but it probably shouldn't be. One California sequence that may not have had many stem scales was a sister species to T. squarrulosum, not T. atrosquamosum, which was unexpected. We need PNW collections without many stem scales to find out which is our species - we don't know yet. It's also possible people have found Tricholoma atroviolaceum with the purple tones faded away and thought it was this. Tricholoma orirubens EU (eventually staining red in places) was reported once in the PNW in 1946, as something resembling T. terreum. It actually is a relative of T. atrosquamosum. We have EU DNA, and nothing here matches it so far, so that rumour is probably not true.

unsequenced possible Tricholoma 'atrosquamosum PNW14' (no stem scales) © Ben Woo,      T. 'olivaceotinctum PNW13' (with stem scales) © Dean Lyons (from CA)


Purple black scaly cap - clade 13

Tricholoma atroviolaceum OR - we have the type sequence, and WA and ID sequences that match it. This looks very much like Tricholoma atrosquamosum but with purple tints in the cap when fresh and supposedly more greyish gills. It needs to be investigated if reports of the latter are sometimes this species.

Tricholoma atroviolaceum © Noah Siegel


Grey (or brownish-grey) and scaly, large - clade 9

Tricholoma venenatoides OR - being newly described as our species long mistakenly called Tricholoma venenatum MI and Tricholoma pardinum EU. Our species is only 3 bp different than T. pardinum so it's not clear to me that it deserved its own species (it is much further from T. venenatum). This species is being described with scales more towards a tan colour (what we used to call T. venenatum). The new paper leaves open that a second species with grey scales may deserve its own name (what we used to call T. pardinum) and shows those sequences cluster separately, but that doesn't seem to be the case. Tan and grey specimens sequence identically in ITS, so I have no idea why their tree shows them separate and until a multi-gene study can be done to see if the tan and grey scaled versions are different in other genes, I am calling all of them T. venenatoides and I'm not convinced they shouldn't all be called T. pardinum. The grey version is more common here than the tan version. Tricholoma huronense was also reported from the PNW but the new paper believes that species is poorly understood and is either different than anything found in the PNW or at least not unique. This needs to be proven.

Tricholoma venenatoides © Danny Miller


Grey and fibrillose, partial veil (may be hard to notice), medium sized, may be found in spring - clade 17a

Tricholoma cf cingulatum EU - sometimes almost white, this one has the most obvious partial veil, often leaving a ring on the stem. It grows under willow. Farinaceous. We have lots of EU sequences, but no local sequences to find out if ours is the same or a sister species. It's distinctive, sometimes having a ring, so the reports of it are probably true.

Tricholoma argyraceum EU - with a faint cortina-like veil. The gills (and stem) may spot yellow in this species and the next. Farinaceous. It's said to be umbonate in the EU but doesn't seem to be here. In California this is called "Stanford Gray" and is found under live oak in the spring, but the DNA was also found in EWA with mixed conifers. The WA sequence is only 3 bp and 1 ambiguous location different than the Swedish type, so it may be the real species. It's very similar to the next species, so we may have two that have both been going falsely under the name T. scalpturatum.

Tricholoma 'scalpturatum PNW15' - very, very similar. We have many sequences from Europe, but BC sequences and soil sample sequences from OR are quite different, so our species needs a new name. We need more collections to find out how to tell this apart from T. agryraceum.

Tricholoma 'terreum IN01' (=terreum EU var. cystidiosum CA?) - has a very weak partial veil that is often overlooked or not always present. That means the differentiating characters from T. argyraceum/cf scalpturatum can be subtle (less farinaceous and never spotting yellow), and it differs from T. moseri below by being a tad larger and usually restricted to the fall. We have the EU type sequence of Tricholoma terreum. Local collections from WA and OR are a somewhat sister species, but closer to the type of Tricholoma bonii EU. Perhaps this is the California described Tricholoma terreum var. cystidiosum CA (although it would need to be promoted to species). It is now accepted that Tricholoma myomyces EU is a synonym of T. terreum, (the former name was used when they noticed the cortina and the latter when they didn't).

possible Tricholoma cingulatum © Ben Woo,     T. argyraceum © Steve Trudell,     T. 'scalpturatum PNW15' © Marty Kranabetter

unsequenced Tricholoma 'terreum IN01' cf. var. cystidiosum © Andrew Parker,     T. 'terreum IN01' cf. var. cystidiosum © Anne Polyakov and Cady Adair


Grey and fibrillose, lacking veil, small, almost odorless, may be found in spring - clade 17b

Tricholoma moseri MX complex (=T. triste EU?) - see T. cf terreum above for veil-less collections that are very similar but not quite as small. T. moseri has no veil and is usually our smallest Tricholoma, yet still fleshy. Commonly found in spring but the DNA from winter and fall collections is in the same clade.

Local sequences are often very close to the Mexican type sequence of Tricholoma moseri (averaging 3 bp), but also very close to the German type sequence of Tricholoma triste (averaging 2 bp and 2 indels further away), which is a far older name if they are the same. A multi-gene study may be needed to figure this out, since collections from all over BC, WA and OR show differences to each other and to the above 2 named species. There may be more than one species hiding here. For now, the recent paper uses the name T. moseri for our collections even though it's not the oldest name, since it is the most local name (Mexico vs. Europe) and since many local sequences are closest to that type.

Tricholoma spp. OR KT800 group - five sequences from OR are 5-10% different than anything else and each other. That is suspicious. So is the fact that that their genbank accession numbers are similar; perhaps something went wrong in this batch of sequences and they are dirty. We'll have to wait and see if these sequences ever show up again before assuming they represent new species. I don't think they do.


Tricholoma moseri (triste complex) © Jonathan Frank


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