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Danny’s DNA Discoveries – Russula

by Danny Miller


Clade Russula “core” - White Spored Members

The gills of older specimens of these species will stay very white, without developing much of a yellow tint at all. Most species are together in a clade, but a few white spored species live in the cream spored clade (R. stuntzi, R. parapallens, R. aff. viscida). These three won't necessarily have pure white spores, but could have a little tint to them.


Russula emetica

This white spored, poppy red or yellow capped hot conifer species has been quite controversial. Over the years, many people have thought that this, the oldest of all Russulas, described in 1774, was also one of our most common Russulas. But then everybody started thinking about it too hard and second guessing themselves and then our Russula was thought to be Russula silvicola or Russula bicolor instead. Well, the jury is in, as there is a surprising consensus on what the real R. emetica is, and that’s what we have. Russula bicolor turns out to be something unrelated in the “crown” clade so how that got to be the leading candidate is beyond me, except that it too can be red and yellow (bi-colorous).

Russula emetica got its name because it was rumoured to induce vomiting (it could be used an an emetic) because of its hot, acrid taste. But as early as 1881, Charles MacIlvaine debunked that myth by feeding it “in quantity” to 20 of his friends (they were willing participants, don’t worry) and having America’s most famous mycologist at the time, Charles Peck, verify its identity for him. I know people who have eaten it recently as well. Perhaps those people before 1881 were just spice wimps. But don’t eat it all the same, it’s not good.

Almost 2/3 of the specimens seem to have some poppy red colouration. About 1/3 of them seem to be completely yellow. This species is sometimes found attached to rotten wood, unusual for a Russula. While many of our specimens share the exact same ITS2 DNA as many from Europe, one specimen from BC has slightly different DNA than most others (2 differences and 2 indels in ITS2) so I’ll be keeping a close eye to see if those differences are real and if they mean anything. Other very similar species are discussed below.

R. emetica © Ben Woo


Russula hydrophila/griseascens/montana

This almost identical looking Russula (formerly considered a mere variety of R. emetica but now known to be significantly genetically different that it can’t be just a variety) can sometimes be just as common as R. emetica. But it’s yellow almost 2/3 of the time and has some red in it only 1/3 of the time (or so). You have to distinguish them microscopically, although this species is more likely to grey in the stem in age. As for its name, all three names may point to the same species. The oldest name is R. hydrophila so that may end up being the official name, but it is only a wide spread assumption for now that it and R. griseascens are the same species (no genetic evidence). Some people still generally refer to it as R. griseascens in the EU, and we’ve been referring to it by the name R. montana (described from Colorado) here in the PNW lately. Trusted samples of both species have the exact same ITS DNA, and both names can be traced back to 1975, so, if R. hydrophila is not the valid name, somebody will have to investigate which came first. In order to not get too controversial, let’s go with the flow for now and continue calling it R. montana. Our local specimens are within 1 difference in ITS1 of the Colorado type. Its presence here was not known until Anna’s DNA study of Ben’s collections. It is probably a conifer species.

R. montana © Ben Woo


Russula spp. Woo 24 & Woo 24a (cf crenulata, aff betularum, aff nana)

Russula crenulata is described from Oregon and I don’t know for sure what it is, but there are two rare genetic species, somewhat separated from each other (not sister species), found here that might fit the description, assuming it’s not the same as one of the other species listed here. Woo 24 was found with spruce and Garry oak and maybe other conifers, in both pink and yellow forms. Woo 24a was found with Garry oak with a yellow form. R. crenulata is described as always yellow with serrated gill edges but it is unknown if that is really a good character to differentiate the species. At least one specimen each of Woo 24 and Woo 24a may have been found with serrated gill edges, and on that basis alone I am hypothesizing that R. crenulata may be one of these two species. Clearly, further studies will need to be done. There is unfortunately no good way of recognizing these species yet. It has not yet been tasted enough to know how consistently acrid it is. Russula cremoricolor is almost identical, without the serrated gill edges, but so far only found in California, mostly under tanoak and not yet this far north.  R. raoultii is another yellow capped species that was said to be found here (but appears not to be).

That all being said, there are only 4-5 ITS differences between Woo 24 and R. betularum (always near birch in Europe) and R. nana (usually near willow in Europe), two relatives of R. emetica. That is not a lot of DNA difference, but since R. nana and R. betularum are considered distinct, and have the same slight amount of ITS difference, I’m not going to state that our species is the same as either of those two. As you can see, sometimes 4 differences in ITS is assumed to be the same and sometimes different species, there’s no hard and fast rule. Mycologists have made species separate with anywhere between 0 and 10 differences in ITS based on other factors. On the cream spored Core clade page, under R. salishensis, you’ll see we did it with only 2 differences.

I use “cf” to mean “compare with”, implying that they look similar, but saying nothing about whether or not they are actually genetically related. I use “aff” (affinity) to mean genetically closely related to.

R. sp. Woo 24 (cf crenulata, aff betularum, aff nana) © Marty Kranabetter and Ben Woo

R. sp. 24a (cf crenulata) © A and O Ceska


Russula parapallens

Confusing the matter even further is that Ben’s study found another new, similar Russula that had been hiding out undiscovered. It too can be either bright red or yellow, but it will often have a splotch of dark colouration in the center of the cap. The spores and gills may seem off-white, not pure white. It may also taste mild, while R. emetica and montana are pretty consistently acrid. It is not quite as common as the those two species, but it’s still pretty common. It gets its (new) name from the fact that it is one of the species where sometimes the red colour fades to a paler yellow colour.

R. parapallens © Ben Woo


Russula phoenicea

Russula fragilis does not occur in the PNW, as commonly thought, but we do have two of our own common species. R. phoenicea is very common, found with douglas fir, and it usually starts out purplish but fades considerably in age and will often have some green or olive tones. It is sometimes hot, but not consistently, complicating its identification unless you note the white spores. On those occasions where it was mild tasting, it was often mistaken for R. lilacea (see my story in the heading for the Crown clade Russula zelleri grouip). We gave it a pretty name because we thought it was a pretty mushroom.

R. phoenicea © Ben Woo


Russula hypofragilis

Our second species mistaken for R. fragilis is found with true fir instead of douglas fir, and so is not quite as common. It is usually purple (fading in age) but without the green or olive tones. It may also be mild tasting. It seemed to me to be not quite as small and fragile as the European R. fragilis, so that’s how it got its name. Reports of R. atropurpurea being found here are so far false and likely refer to this species.

R. hypofragilis © Ben Woo


Russula stuntzii

This similar Russula is usually grey, but often with lavender tones. Russula phoenicea and hypofragilis have the purple tones, but not the grey. It’s not as closely related to the core white spored group, and the spores may be off-white. The taste is occasionally mild and it is usually a Doug fir/hemlock species. It was described from Washington in 1979 by Darryl Grund to honour his professor, UW mycologist Daniel Stuntz, in whose memory the foundation that paid for sequencing Ben’s Russulas was created.

R. stuntzii © Steve Trudell


Russula ‘laccata’

We also have some rare, not well understood whitish spored hot Russulas in this clade. One rare European Russula, R. laccata, not proven to exist here before the study, is found under willow and has a darker wine-red cap (not poppy red like the similar R. parapallens) that fades in places to creamy yellow. It has only been found (or at least recognized) once at Whistler and once near Victoria, BC. With no or maybe 1 ITS2 difference and 2 ITS1 differences, for now I’m going to assume that ours is the same species as R. laccata from Europe. The next closely related species is probably R. atrorubens, with 3 ITS2 and 2 ITS1 differences from European laccata, not a lot of differences, yet that is accepted as a distinct species.

R. laccata © Ben Woo


Russula sp. Woo 29 (aff viscida)

Another rare Russula is Russula aff viscida, a similar wine-red capped mushroom (perhaps with paler areas) with mostly white spores and only slightly acrid taste, best recognized by a stem that browns considerably in age. There are two possibilities for what DNA represents the true European R. viscida, and our species is not the one most commonly found there, so I am assuming that ours is a sister species in need of a new name (aff meaning affinity to, ie. closely related). Even if the other less common possibility turns out to be the “real” R. viscida, ours has 2 ITS2 differences and maybe 1 indel from that species, so it could still conceivably be in need of a new name. It is not known to have been photographed fresh here.

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