Inocybaceae

© Andrew Parker

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

Click here for my Pictorial Key to Inocybe s.l.

Introduction

Recognized by a usually tattered appearance, sometimes called "fibre heads". I mention unusual groups of mushrooms (like Psathyrella) that have a cellular cap cuticle, composed of spherical cells that can break up in any direction. In contrast, Inocybe is the poster child for the typical kind of mushroom cap. Made up of long fibrous material, the caps will usually only split radially from the centre out to the edge of the cap. The smooth capped species are hard to recognize, but the typical Inocybe cap is dry, fibrillose or scaly, not hygrophanous and often umbonate. There is often a small bulb at the base of the stem, and the stem apex may be pruinose - these are important characters to note when trying to identify one. They are mycorrhizal, and can also be recognized by their odor, usually an unpleasant spermatic smell. They also usually have a cortinate veil like Cortinarius, and are actually very easily confused with some Telamonias, which usually lack scales on the cap, lack the spermatic odor and never have a bulb. Most Inocybes are suspected to be poisonous, containing muscarine, and due to their being ubiquitous near almost every forested area, they are responsible for many of the accidental mushroom poisonings by children and pets. Inocybe spores may take a while to mature, leaving the gills white for a long time, so it is hard to tell that they are brown spored until they are old. This is a good reason to always consider other possible spore colours unless you have proven what the spore colour is by taking a print. Very difficult to tell apart, Inocybe is one of those genera that most identifiers cannot usually get to species. Only a few species are colourful, and the rest are usually just shades of brown.

However, there are very interesting things to see under a microscope. Some Inocybes have cystidia, sterile cells on the gills, that are shaped like bowling pins with bad haircuts, called "metuloids". Some of those have very distinctive warty or nodulose spores. The ones without the interesting cystidia represent the oldest evolutionary lineages in the family, but interestingly enough, the warty spored species are not a related group; warty spores seem to have evolved back and forth a few times in Inocybe, something I can't explain.

Inocybe metuloids © Danny Miller and nodulose spores © A and O Ceska

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

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Inosperma, Mallocybe and Pseudosperma - click to expand
The few species without metuloids represent older lineages and have been split into their own genera, which is unfortunate, because that makes those individual genera very difficult to recognize. I think I would have preferred considering them all to be Inocybe, but then other mushrooms around the world that don't seem quite so Inocybe-like would have to be called Inocybe as well, and those people might have objected. Fortunately, as a group they are easy to recognize under a scope - no metuloids. For a key to the individual genera and much more information, see Brandon's paper.
Species mentioned: Inocybe calamistrata, hirsuta, mucidiolens, maculata, lanatodisca, neobrunnescens var. leucothelota, fibrillosa, subdecurrens, dulcamara, terrigena, delecta, leucoblema, breviterincarnata, flavella, holoxantha, niveivelata, obsoleta, occidentalis, rimosa, sororia, spuria

Inosperma
Inosperma calamistratum group - recognized by being distinctly scaly all over, brown but with blue-green spots on the stem base and sometimes turning red where handled. I think a study showed that this genus contains neither Psilocybin (the bluing is unrelated) nor the poison muscarine unlike most in Inocbye s.s. The odor is raw fish, pine resin or green corn, not the usual spermatic odor.
Inosperma aff. calamistratum - Brandon has Inocybe calamistratum both in the EU where it was described and here in North America, but our local sequence are more than 2% different from the sequence that he and Kropp have said is an actual sequence (there are many competing concepts in UNITE as there are many lookalikes). Perhaps the real thing is somewhere in North America, but apparently not here, and I think ours needs a new name.
Inosperma cf. calamistratum #1 - Not only that, but we have a second unnamed species, much more distantly related, that is in need of a name.
Inosperma maximum (=Inocybe hirsuta var. maxima) WA - more robust, more red staining and fewer blue areas.
Inosperma mucidiolens NS (=Inocybe calamistrata var. mucidiolens) - when described, it was verified to occur in WA too (I think we have an isotype?) One WA sequence is 3 bp and 2 indels different from the Nova Scotia type sequence, but it is officially the same species. It supposedly has a more moldy or green corn odor, whereas the others are more raw fish and pine resin.

Inosperma aff. calamistratum © Luca Hickey

Inosperma maculatum EU - a nondescript dark brown mushroom with a scaly cap, an umbo (possibly covered with bits of white veil material) and a little stem bulb. It has a complex odor. While many Inocybe are close to this description, this is the only one without metuloids. We have an official sequence from Kropp from the EU, and reports from the PNW, but no local DNA yet to prove it. We need local sequences to prove it's here. Reports may be the following unnamed species instead.
Inosperma aff neobrunnescens var. leucothelota NS - we have a couple Seattle sequences that were identified as this species, but do not match the NS type sequence. It may need its own name. It should also be investigated if reports of I. maculatum are actually this closely related species. We need more local sequences to see how common this is.
Inosperma lanatodiscum MI - similar, but a slightly different shade of brown and with a different complex odor. We have a MA sequence that Kropp says is close enough to the type area of MI to represent the real thing. One dirty WA sequence is a pretty good match once cleaned up, but we could use more sequences.

Inosperma maculatum/lanatodiscum group © Danny Miller

Mallocybe
Mallocybe fibrillosa 1888 NY/subdecurrens 1889 NY? (Mallocybe 'dulcamara' EU) (=Mallocybe delecta EU?) - a wooly orange-brown species. Brandon's east coast sequences of these two east coast species are practically the same, different by a couple bp and a few ambiguous locations, so they may be synonymous, with M. fibrillosa being slightly older. However, he hypothesizes that the Mallocybe delecta EU may be the same, and is even older, but we have no sequences of that yet to prove it. This is the species we have been calling Mallocybe dulcamara EU in the PNW, and some EU sequences of M. dulcamara do match ours, but Brandon says those collections are misidentified and the real M. dulcamara in Europe will likely be shown to be something different.
Mallocybe cf terrigena #1 - similar, perhaps with a scalier stem and a ring zone? this is not the EU species (our sequences don't match Brandon's EU sequences), and it's not too closely related either, so I won't call it "aff. terrigena". But that's what five collections from BC were labeled as. It probably needs a name.
Mallocybe cf terrigena #2 - Pemberton BC and Alaska have sequences of an additional species resembling M. terrigena, but not that.
Mallocybe cf leucoblema EU -pale cap with a brown disc. we have Brandon's official EU sequences, but no local sequences yet to prove that's what we have here. We need local collections.
Mallocybe aff. malenconii EU - we have many sequences from the EU of this, and a SE BC sequence that is a almost 2% different and probably represents a sister species. (Alberta appears to have its own unique sister species too). M. malenconii is described as another pale capped species with crowded gills, but I don't know if our sister species will look the same.
Mallocybe sp. Drew 060305 WA - one WA sequence is quite different from all the others. I have no idea yet what it looks like.
Mallocybe sp. Table Mountain WA - another WA sequence is on the same long, unique branch as the previous species. I have no idea what it looks like either.

Mallocybe fibrillosum/subdecurrens © Buck McAdoo, M. cf leucoblema © Andrew Parker

Pseudosperma
Pseudosperma sororia group - straw coloured, large, umbonate and quite tattered. May smell spermatic or like green corn. Kropp did a big study in Utah of this subgenus of Inocybe (now genus Pseudosperma) and found that instead of the 1 species in this group we thought we had, we actually have at least 9 lookalike species. Oh boy. Kropps' paper provides a key to many of the species in this genus.
Pseudosperma sororium MI - we have WA and ID sequences, but we need east coast sequences to prove we have the real thing.
Pseudosperma rimosum EU - reported often from the PNW, but no local DNA matches Kropp's EU DNA yet, so it may not be here. This was the only commonly known species in the genus for a long time, so all our species have long gone incorrectly by this name.
Pseudosperma breviterincarnatum UT - pink young gills. Kropp provided 6 sequences from WA that match his UT type sequence.
Pseudosperma cf flavellum EU - perhaps a brighter yellow cap. Kropp reported it From Idaho but did not provide the sequence, so we still need sequence proof that it is here. He did provide an official EU sequence to compare to, which disagrees with the sequence of most genbank collections labeled this. This should be sorted out.
Pseudosperma aff flavellum - we do have a Victoria BC sequence that clades close to the various concepts of P. flavellum, but doesn't match any of them. This could be what Kropp found in Idaho, or, if he found the real thing, this could be an additional species.
Pseudosperma holoxanthum WA - also rather bright like P. flavellum. we have a NS paratype sequence but it would be nice to get local sequences of this local species.
Pseudosperma niveivelatum UT - white cap. we have the UT type sequence and 2 matching WA sequences.
Pseudosperma aff. obsoletum EU - pinkish- or brownish-grey cap (most others are yellow-brown). UT and WA sequences are a few % different than Kropp's EU sequences, so we appear to have an unnamed sister species.
Pseudosperma occidentale UT - the one lacking a distinct umbo. A WA sequence matches the UT type sequence.
Pseudosperma bulbosissimum EU - one old WA sequence matches Brandon's EU sequences.
Pseudosperma sp. 1 WA - one Washington collection has a unique sequence and likely represents an undescribed species. I cannot tell it apart from P. sororium.
Pseudosperma sp. 2 OR - one Oregon collection has a unique sequence and likely represents an undescribed species. I cannot tell it apart from P. sororium.

Pseudosperma sororium, sp.1 and sp. 2 © NAMA and the Field Museum of Natural History

Inocybe - smooth spores - click to expand

These species have metuloids. They also have smooth spores but that is not genetically important - the smooth spored and nodulose spored species are mixed in together, meaning, surprisingly enough, that nodulose spores appear to have evolved multiple times, something I can't quite explain. Chances are you're going to need a scope to identify your Inocybe anyway, so I don't feel too bad about making you use a scope to know which section to expand (something I usually try to avoid).

Species mentioned:

Inocybe - nodulose spores - click to expand
These species have metuloids. They also have nodulose spores.

Species mentioned:

Here we go

Inocybe sp. © me

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