Melanoleuca

Melanoleuca (without stinging cystidia) - click to expand

Species mentioned: Melanoleuca melaleuca, angelesiana, graminicola, stridula, microspora. Hebeloma oregonense.

'Acystidic' species previously reported from the PNW before DNA: Melanoleuca melaleuca EU (a dubious name that should be abandoned), Melanoleuca stridula EU (never found here so far) and Melanoleuca angelesiana WA (a common local species that some thought might be the same as the older Melanoleuca graminicola EU but it isn't).

So what is actually found here?

Melanoleuca angelesiana WA - a spring snowmelt species described from WA with a dark grey cap. 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. One sequence we have from OR that matches the type very well is unusually stocky, but it is typically more slender.

Melanoleuca 'angelesiana PNW03' - a couple of winter southern OR sequences from Jan. and Feb. were different by 6 bp and 3 long missing chunks in ITS. Then a match was found much further north on San Juan Island WA in March. This species seems to have a more consistently darker disc and paler rim when fresh, although M. angelesiana is described as sometimes being that way too.

Melanoleuca angelesiana (typical) © Yi-Min Wang, M. angelesiana (stocky version) © Dick Bishop, M. 'angelesiana PNW03' © Jonathan Frank

Melanoleuca 'melaleuca PNW01' - fall species with a dark grey cap and modest size. We should probably all stop using the name M. melaleuca, not just in the PNW, 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 probably should not call any of our species M. melaleuca, nor Melanoleuca stridula (which has been done) as that neotype sequence from Italy does not match any local DNA yet. Whatever this is, we have sequences from western WA and ID.

Melanoleuca 'melaleuca PNW02' - a collection from the WA/ID border and a CA collection have a unique sequence about 2.5% different than anything else. One was stocky and caramel coloured but the other was more slender and darker brown, so all we know is that it doesn't have the stinging cystidia, and the spores measure about 6-7(8) x 5-6(7)u.

Melanoleuca 'melaleuca PNW01' © Danny Miller, M. 'melaleuca PNW02' © Andrew Parker and Alan Rockefeller

Melanoleuca CA03 - 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 that showed us another Melanoleuca existed in the PNW. We have now finally found and photographed it again, from WA and CA. The stem is somewhat orange-brown.

Melanoleuca brachyspora EU - one ID collection turned up this surprise, matching the holotype sequence, not before known from the PNW. Officially, it recognized by a cylindrical stem, white flesh in the stem base, and a caulohymenium.

Melanoleuca CA03 © Kendra Dedinsky (2 images), M. brachyspora © Ed Barge

Melanoleuca '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 (with stinging cystidia) - click to expand

Species mentioned: Melanoleuca verrucipes, cognata, evenosa, strictipes, eccentrica, exscissa, brevipes, griseobrunnea, humilis, communis, subcinereiforma, subcinereiformis, 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). However, PNW04 below seems to have off-white gills too. 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 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 'strictipes PNW04' - these two OR collections looked a bit superficially like Melanoleuca cognata (somewhat stocky and with off-white gills) but sequenced next to Melanoleuca strictipes. More study is needed; perhaps this unnamed species represents local reports of M. evenosa, or perhaps we have both this and M. strictipes in the PNW.

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. 'strictipes PNW04' © 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 spring and fall grass species with especially short stinging cystidia. This species has a rather pale stem and stem flesh, and a darker disc, but otherwise quite variable.

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 grey-brown capped species (here yellow brown) with especially short stinging cystidia but it has a darker stem and stem flesh than M. exscissa, and is probably more reliably slender, without a dark disc.

Melanoleuca 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 subcinereiformis OR ('subcineriforma') - since Melanoleuca requires a feminine ending, the correct epithet for the species is Melanoleuca subcinereiformis, although you still might see M. subcineriforma. This recent re-discovery from WA and ID matches the recently sequenced type collection from Oregon. It is a modest drab grey to dark grey Melanoleuca (resembling M. cf melaleuca and M. angelesiana, except this species has the stinging cystidia) but not much more is known. The type was sequenced as part of a recent Tricholoma study, as it was thought by some that it might be a Tricholoma instead, but no, it is indeed a Melanoleuca.

Melanoleuca polioleuca EU (=M. friesii EU) - another "melaleuca-like" species except for having the stinging cystidia. Microscopically, you can tell you have one of these 2 species, but I'm not sure yet how to tell them apart. One ID collection has a sequence that matches the EU epitype. I hear the epitype sequence of M. friesii matches too, making that a newer synonym. I have a sequence I believe matches the epitype (from the same collections) and it indeed seems to be the same species.