Danny’s DNA Discoveries – Melanoleuca of the PNW
Melanoleuca may best be recognized by often having an elegant
Amanita/Pluteus-like stature (they are in fact in the Pluteaceae
but never developed their free gills nor pink spores) - they usually have a
wide flat cap, close to crowded gills and a narrow straight stem.
The gill attachment is never reliably the same, so unfortunately, they might be
notched, adnate or slightly decurrent (the latter of which would make them
easily confused with clitocyboid mushrooms). The caps are not usually viscid
but perhaps slightly greasy or hygrophanous. There is no partial veil.
They only come in boring shades of white, grey or brown. Even knowing all
that, they are still often hard to recognize until you get used to that elegant
Melanoleuca gestalt. Normally they are 5-10cm, except for the larger,
stockier ones, which do not quite have the elegant Melanoleuca "look" and
are easily confused with Lyophyllum,
another tricky genus.
Melaoleuca spores and some species' cystidia © First Nature and Lucas Large
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:
Melanoleuca (without stinging cystidia) - click to expand
Species mentioned: Pluteus cervinus, exilis, primus, orestes, parilis n.p., pouzarianus, atromarginatus, laricinus, salicinus, petasatus, magnus, leucoborealis, brunneidiscus, washingtonensis, heterocystis, pellitus, nothopellitus, hongoi
'Acystidic' species previously reported from the PNW before DNA: Melanoleuca melaleuca EU, Melanoleuca stridula EU and Melanoleuca angelesiana WA (a local species that some thought might be the same as the older Melanoleuca graminicola EU).
What we now know:
Melanoleuca cf melaleuca EU - we should probably all stop using the name M. melaleuca, even though it's the one species name most people have heard of. It was the first Melanoleuca to be described back in 1801, but rather vaguely, so nobody knows what it is. People can't even agree on if it has the stinging cystidia or not. Popular opinion seems to be swaying towards thinking it doesn't, so it would belong in this section, but there are about a half dozen genetic species in the EU going by this name, all within 4% of each other in ITS. So we kind of know what it might be (at least we have a group of species that it might be part of), but the odds are the genetic species in the group found in the PNW is not going to turn out to be the real thing, unless the entire group is determined to be one species (which is doubtful because some species in the group are already named something else, like Melanoleuca graminicola). We have a neotype sequence from Italy of Melanoleuca stridula, and our local species does not appear to be that after all. This species is usually recognized by a dark grey cap and a modest size.
Melanoleuca angelesiana WA - described from WA, this is our dark grey capped spring snowmelt species. Some authors have wondered if we needed our own name for this, as it might just be the same as the EU species Melanoleuca graminicola, but we have a few EU sequences purporting to be that, and they are different. So the proper name for our dark spring species is M. angelesiana, not M. graminicola. The sequence we have from OR that matches the type very well is unusually stocky. I'd like to see additional sequences of the normal, slender version.
Melanoleuca aff. angelesiana - a couple of OR sequences from Jan. and Feb. are different by 6 bp and 3 long missing chunks in ITS, so they might need their own name.
Melanoleuca sp. iNat43029235 - a single collection from the WA/ID border had a unique sequence about 2.5% different than anything else. All we have is this photo, the fact that it doesn't have the stinging cystidia, and the spores measure about 6-7(8) x 5-6(7)u.
Melanoleuca "Hebeloma oregonense" - when we tried to sequence the type of Hebeloma oregonense from OR, it turned out to be a Melanoleuca sequence. There was obviously some kind of mixup, but if the Melanoleuca that was accidently sequenced was something picked in Oregon, that means we have an additional species in this section, because it was a unique sequence. If the sequence didn't come from something in the PNW, then forget everything I said about it.
Melanoleuca cf 'microspora' MT - an illegal name that needs to be changed, because when this was described from Montana in 1977 (reportedly also found in Idaho and Alaska), there already was a Melanoleuca microspora from 1914, which was something formerly thought to be a Tricholoma discovered in 1887. Well, they were also wrong about it being a Melanoleuca and it was eventually renamed in 1973 to Cystolepiota microspora, and even though that older mushroom is not a Melanoleuca, since it was once thought to be, they shouldn't have reused that name for the 1977 Montana Melanoleuca. Melanoleuca used to be a catch-all genus for some unknown mushrooms, so a lot of non-Melanoleucas used to at one point have a Melanoleuca name. Many still do and haven't been corrected yet. We have no type sequence or recent local collections, so we need to figure out what this is and if it is a duplicate of one of the above mentioned species (it might be). It is recognized by having no stinging cystidia and having slightly shorter and rounder spores than the other species.
Melanoleuca cf melaleuca © Danny Miller, M. angelesiana (stocky version) © Dick Bishop, M. aff angelesiana © Jonathan Frank, M. sp. iNat43029235 © Andrew Parker
Melanoleuca (with stinging cystidia) - click to expand
Species mentioned: Melanoleuca verrucipes, cognata, evenosa, strictipes, eccentrica, exscissa, brevipes, griseobrunnea, humilis, communis, polioleuca, friesii
Melanoleuca verrucipes EU - easily recognized by being all white with black scabers on the stem (as in Leccinum). This was seemingly introduced to our area only in the last 20 years or so, and confused us at first when it started popping up.
Melanoleuca verrucipes © Richard Morrison
Melanoleuca cognata EU - this somewhat stocky species can be quite variable in habitat and colour, and some suspect there might be a group of species. It is probably best recognized by creamy yellow spores and therefore gills in age (instead of the usual white). Most EU sequences agree on what the real species is, and one BC and one WA sequence match those, so we do appear to have the real thing.
Melanoleuca cf strictipes (evenosa) EU - we used to call this Melanoleuca evenosa, but Vizzini synonymized that with the older Melanoleuca strictipes and nobody seems to disagree. We have no recent collections to sequence, but it has usually been reported across the PNW at high elevations under conifers in spring. We need new collections to sequence to verify what these reports really are.
Melanoleuca aff strictipes/cf cognata - these two OR collections looked a bit superficially like Melanoleuca cognata (somewhat stocky) but sequenced next to Melanoleuca strictipes (evenosa). More study is needed; perhaps this unnamed species represents local reports of M. evenosa (strictipes), or perhaps we have both this and the real thing.
Melanoleuca eccentrica WA - Smith described this in 1944 as a small, nauseating Melanoleuca with an off-centre stem and no cystidia, but it turns out he may have found an atypical specimen, because the type sequences matches well with three recent WA collections that are large with a central stem, and although difficult to find, there were cystidia (although they lacked the encrustations that made them look "stinging"). Ours also were pleasant smelling and tasting, not nauseating, and two of them had a creamy yellow spore print like Melanoleuca cognata. That explains why it had never been reported since. So this needs more study and the literature needs updating to reflect the actual description of the mushroom. It makes me wonder if the type collection that was sequenced really was the same specimen Smith described so differently. It can be recognized by its large (but not stocky) yellow-tan cap yet slender yellow-tan stem. It is found in forests, but often there seems to be grass nearby.
One collection differs from the ITS1 only type sequence by 5 bp and 1 indel in ITS1, but only differs by a single bp in ITS2 from sequences that match ITS1 of the type sequence very closely. It differs subtly microscopically from the type as well. It should be investigated if there is one or more species here in the complex.
Melanoleuca cognata © Buck McAdoo, M. aff strictipes/cf cognata © Josh Powell and Jonathan Frank, M. aff eccentrica © Richard Morrison
Melanoleuca exscissa EU - when I first discovered this, I thought it was the lookalike Melanoleuca brevipes, but sequencing showed what it really was, and it has since been found and sequenced in WA three additional times. It is a small, dull brown, spring and fall grass species with especially short stinging cystidia. This species has a rather pale stem and stem flesh.
Melanoleuca griseobrunnea Korea - similar to Melanoleuca exscissa (and related to it) this Korean species is known from sandy roadsides and grass, and ours is the first report outside of Korea (found in OR in grass). It is also a slender grey-brown capped species (here yellow brown) with especially short stinging cystidia but it has a darker stem and stem flesh than M. exscissa.
Melanoleuca exscissa © Danny Miller, M. griseobrunnea © Bruce Newhouse
Melanoleuca cf humilis EU - we have a type sequence, but although this has been reported from the PNW infrequently, we don't have any local sequences or recent collections to verify these reports. We'll need more local collections to find out if it's really here, or what the reports actually represent. It is a small, short stemmed Melanoleuca that is rather vaguely described and hard to recognize, so that casts doubt on its occurrence here.
Melanoleuca aff. communis MX/aff. polioleuca EU/aff. friesii EU - this recent discovery from WA and ID sequences within 2% of many sequences from Mexico labeled M. communis, and EU sequences labeled M. polioleuca and M. friesii. It is a modest drab grey to dark grey Melanoleuca (resembling M. cf melaleuca and M. angelesiana, except this species has the stinging cystidia) about which not much more is known. It may need its own name.
Melanoleuca aff communis/polioleuca/friesii © Danny Miller
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