Clitopilus s.l.

© Steve Trudell

Danny’s DNA Discoveries – Clitopilus s.l. of the PNW
by Danny Miller

Click here for my Pictorial Key to the Entolomataceae

Introduction

These genera do not have as strongly angled spores as the rest of the Entoloma family, or the angles are only visible from certain aspects, which makes the angles harder to see under a scope. Sometimes the spore print colour is barely pink at all. Combined, these features can make these species hard to place in the Entolomataceae family (pink angled spores with attached gills). Even Entoloma lumpers do not call these species by the name Entoloma proper. There is little controversy about the names I use on this page. Either you call them all species of Clitopilus (which few people are doing) or you split them into these 5 genera. I do not understand why the Europeans are willing to split these few mushrooms into 5 tiny genera, but they are not willing to split Entoloma like I do, so thousands of species are in the Entoloma genus.

Clitopilus - pink spored oyster mushrooms will either be in this genus, or if the spores are more strongly and obviously angled, in Claudopus. Clitopilus also contains non-oysters. In this genus, the spores that happen to be in polar view (where you are looking at the top or bottom of the spore) will appear angular from ridges along their longitudes. The spores that are laying on their sides may appear smooth without a high quality, powerful lens or electron microscope.

Rhodocybe - the spores in polar view may appear angular from prominent pustules, but not entire longitudinal ridges. This difference may be hard to see without an electron microscope. These species have no clamps.

Rhodophana - similar to Rhodocybe, but with clamps. In the PNW, they are bright orange and strongly farinaceous.

Clitopilopsis - the pustules are more obscure, making the spores often appear smooth even in polar view without a high quality, powerful lens or electron microscope. Spore walls are thickened.

Clitocella - similar to Clitopilopsis, but thin spore walls. None are known from the PNW yet, but it is known from northern California.

Rhodocybe nuciolens spore print © Yi-Min Wang. This pale colour and the subtlety of the angles on the spores makes these species hard to identify.

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:

so far Clitopilus prunulus and something close to C. baronii, C. hobsonii, and C. kamaka have been sequenced from the PNW.

We have 4 species in the Rhodophana nitellina complex.

We have additional possibly undescribed species of Rhodocybe of all colours (orange, grey and brown) besides the known R. nuciolens, R. caelata and R. aureicystidiata, respectively.

Clitopilus - click to expand
In the PNW, this genus contains a white clitocyboid species and little white oysters (easily confused with Entoloma s.l. oysters in the genus Claudopus , which are grey or brown and have more strongly angled spores).
Species mentioned: Clitopilus prunulus, cystidiatus, hobsonii, baronii.

Clitopilus prunulus EU - this white to pale grey clitocyboid, with strongly decurrent gills, nicknamed the sweetbread mushroom for its strong farinaceous odor. Most sequences of it seem to be incorrectly labeled Clitopilus cystidiatus, with rare cystidia instead of none, so I used to think that might be the name of our species. But now we have an epitype sequence from Austria, the type area of C. prunulus, that matches our sequences, so that should be the proper name of our species. It is the older of the names as well.
Clitopilus 'baronii PNW01' - a little white oyster found on a decaying polypore. It is 7 bp different in ITS from the EU type sequence, and might need its own name.
Clitopilus 'hobsonii CA02' - almost identical to C. baronii, but growing on wood. Our one OR sequence differs in ITS1 by 1% from the UK type sequence, but almost matches in ITS2.
Clitopilus 'kamaka PNW02' - this little white oyster species, 3% different in ITS than the NZ species C. kamaka, has very few rudimentary gills, unlike any other known PNW pink spored oyster.

Clitocybe prunulus © Buck McAdoo, C. 'baronii PNW01' © Lauren Ré, C. 'hobsonii CA02' © iNaturalist user fungi_fanatic, C. 'kamaka PNW02' © Connor Dooley

Rhodocybe - click to expand
Brown, grey or orange mushrooms of collybioid or omphalinoid stature. See also Clitopilopsis for a somewhat farinaceous grey, slender, long stemmed choice and Rhodphana for a strongly farinaceous bright orange choice. Species in this genus are not going to be easy to differentiate.

Species mentioned: Rhodocybe nuciolens, hondensis, aureicystidiata, dubia, caelata, tugrulii.

Rhodocybe nuciolens WA - pinkish cinnamon to orangish with a somewhat fragrant or nutty odor. Rhodophana are brighter orange with a strong farinaceous odor. We have 4 WA and OR collections, and it is also found in CA under redwoods. They have an additional species under CA redwoods, R. hondensis, that is smaller and more thin fleshed with a darker cap and paler stem, but it is not known from further north yet. We do not have ITS DNA for R. hondensis.

Rhodocybe PNW01 - we don't have a great photo of it yet, but it appears to be an orange-brown species. It was found once in WA and once in OR, and is in a somewhat sister relationship to R. nuciolens.

Rhodocybe nuciolens © Richard Morrison and Jacob Kalichman,     R. PNW01 © Buck McAdoo

Rhodocybe 'caelata PNW02' - this little grey species found once in grass in a prairie in WA (it is not as slender nor with as long a stem as Clitopilopsis) appears to be a species complex in Europe, with this species of ours matching one of the possible concepts.

Rhodocybe 'caelata PNW03' - this little grey species found a few times in a conifer forest in WA and once in ID seems to be distinct from all of the EU complex members. It is 8% different in ITS from PNW02, for instance.

Rhodocybe 'tugrulii PNW04' - this single WA collection of another little grey species is 4 bp, 1 indel and 3 ambiguous locations different from the Turkish type sequence of R. tugrulii, so it may be distinct.

Rhodocybe CA01 - one WA sequence matches a bunch of CA sequences. This grey species is close to Rhodocybe griseonigrella EU.

Rhodocybe 'caelata PNW02' © Sarah Hamman,     R. 'caelata PNW03' © Jacob Kalichman (2 images),     R. 'tugrulii PNW04' © Buck McAdoo

Rhodocybe CA01 © Matthew Koons

Rhodocybe aureicystidiata WA - a brown species mostly adnate gills with a dark brown cap, and dark brown stem that may stain reddish where bruised. This native species has been sequenced 4 times from WA so far.

Rhodocybe 'dubia PNW05' - a similar brown species with a whitish bloom and slightly decurrent gills, sequenced 4 times from WA. One microscopic workup seemed to match R. dubia, but we don't have sequences of that EU species to know if this is true or not.

Rhodocybe PNW06 - found twice in WA, this brown species had a stem that is longer and more slender than the others.

Rhodocybe aureicystidiata © Yi-Min Wang and Matthew Koons,     R. 'dubia PNW05' © Jacob Kalichman (2 images)

Rhodocybe PNW06 © Jacob Kalichman (2 images)

California has additional species, not found yet in the PNW.

Rhodophana - click to expand
Strongly farinaceous bright orange collybioids, probably more brightly coloured and more strongly farinaceous than similar Rhodocybe. All our species seem at least slightly umbonate.
Species mentioned: Rhodophana nitellina.

Rhodophana 'nitellina PNW01' - we don't have type area EU sequences of R. nitellina yet, but AK, AZ and MX sequences all differ significantly so this seems to be a species complex and I don't think any of our species are the real thing. I also don't yet know how to tell our genetic species apart. #1 was found twice in WA.
Rhodophana 'nitellina PNW02 - seemingly the most common of our species. #2 was found 4 times in WA.
Rhodophana 'nitellina PNW03' - found once so far at Breitenbush, OR.
Rhodophana 'nitellina PNW04' - found once in WA so far. It doesn't match any other sequence yet, worldwide.
Rhodophana 'nitellina PNW05' - found once in WA so far. It has close matches (but still maybe distinct) in MX and AZ.
Rhodophana 'nitellina PNW06' one ID collection is delicate and dull coloured by comparison.

Rhodophana 'nitellina PNW01' © Yi-Min Wang, R. 'nitellina PNW02' © Yi-Min Wang and Steve Trudell, R. 'nitellina PNW03' © Christian Schwarz

Rhodophana 'nitellina PNW04' © Yi-Min Wang, R. 'nitellina PNW05' © Lauren Ré, R. 'nitellina PNW06' © Ed Barge

Clitopilopsis - click to expand
One slender grey mushroom that may have a long stem, may be convex capped or slightly umbilicate and may have slightly decurrent gills. Perhaps somewhat farinaceous. More collections are needed to learn to differentiate it macroscopically from the several grey Rhodocybe with thinner spore walls.
Species mentioned: Clitopilopsis hirneola.

Clitopilopsis PNW01 - EU type area sequences of Clitopilopsis hirneola EU can differ by at least 5 bp, with one outlying sequence being significantly different, and our single WA sequence so far differs by between 3 and 8 bp and 5 amiguous locations from them. Either there is variability in ITS or this is a species complex so for now this is getting a species code.
Clitopilopsis PNW02 - closer to the real thing than PNW01, this is different enough to possibly be a unique species, at <1% different in ITS than PNW01. It is between 4 and 12 bp from various possibilities for the real thing.

Clitopilopsis PNW01 © NAMA and the Field Museum of Natural History, C. PNW02 © Yi-Min Wang (2 images)

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