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Danny’s DNA Discoveries – Russula

by Danny Miller

 

Clade Russula “crown” - Other Russulas

 

Russula graminea

This European Russula is fairly closely related to the R. zelleri group, described on the "zelleri group" page. It is green or greenish-yellow, so it could be mistaken for R. aeruginea and possibly others. Four Alaskan collections, however, only have some green, usually on the disc, with the rest of the cap being purple (the most common colour of other R. zelleri group members). It was not known from the PNW until Anna’s study of Ben’s collections. Our DNA is basically an exact match to R. graminea in Europe, with the exception of some confusion about how long a string of identical letters might be in a couple of places. This likely represents not being able to reliably tell the length of the string, not actual differences. Everybody probably mistook it for R. aeruginea and never looked at it too closely, but it is just as common (or not uncommon) as R. aeruginea is. It is known as a spruce species in Europe, but here it can also be found with our common conifers like Doug fir and hemlock. In Alaska, it was always found in a spruce-hemlock forest. The hot tasting yellow-green European Russula urens/cuprea that has been reported as being commonly found here has no evidence of actually existing in the PNW. R. graminea was once recorded as hot tasting, so this is probably the basis of those reports. If you find a hot green Russula with dark yellow spores, save it so we can double check.

R. graminea © Ben Woo

 

Russula sp. Woo 48

These next two species are also somewhat related to R. zelleri, but not closely enough to look like it nor necessarily share many of its properties. R. sp. Woo 48 was found once in Shelton near Olympia, WA near unspecified conifers. It had some purple in the center but the rest was pale to medium brown or had faded to brown. We don’t know what its usual colour scheme would be and if it can mimic the other purple species or not. For now, I can't say anything about how to recognize it.

R. sp. Woo 48 © Ben Woo

 

Russula sp. Woo 49

A sister species to sp. Woo 48, it was found once near Satus Pass in S. Central WA near pine and Garry oak, it was entirely cream coloured with little pigment. Also found near Santa Cruz, CA, where it was reported as red and yellow, and near Sly Park CA. It is not known what its usual colour scheme is. Very little is known yet about how to recognize either of these species.

R. sp. Woo 49 © Ben Woo

 

Russula sierrensis

It turns out one of our not uncommon local Russulas is an almost perfect genetic match to the California species R. sierrensis. It can be found all over the PNW (from the Idaho interior to the Washington Cascades to the Oregon coast) under conifers (either Doug Fir or spruce seem to always be present, although in California it’s reported with oak and pine). The reason we never noticed it north of the California border before is that this study showed it doesn’t often look like it did when it was first found, it’s a much more variable-looking species than ever thought, so it was never recognized. Unfortunately, I have no good means of identifying it yet, but this species should be studied in more detail since it is not uncommon (Ben found it 14 times). It’s supposed to be a mild tasting purple-red Russula with a pale yellow spore print, but the spore print can often be dark yellow and the colour can be almost anything. Oh look upon the many faces of Russula sierrensis and despair. It’s possible one of these specimens could have gotten mixed up and not be this mushroom, but not all of them. Any Russula not confidently identified as something else (and that might be most of them) should be microscopically examined carefully for a match to this species, with separate spore warts that rarely connect and pileocystidia (special cells in the cap cuticle not always present in other species). It would be really helpful to get a reliable description of this species. As previously stated, it is somewhat related to R. vinosa, although this species does not stain.

The many faces of R. sierrensis © Ben Woo

 

Russula sp. Woo 64 (aff velenovskyi)

This rare mushroom, related to R. sierrensis and others in the R. vinosa group, does not stain and was only found once under an introduced birch tree in Seattle. It is about 5 bp different in ITS2 (~0.7%) than the European species and may represent a unique species. In Europe, it has been found with other kinds of trees as well including conifers. It has a peachy-orange cap and creamy yellow spores that are not as dark as most of the others. It kind of resembles R. vinososordida but does not stain.

 

R. sp. Woo 64 (aff velenovskyi) © Ben Woo

 

Russula nitida

This is a European birch species with a purple-brown cap and a flushed stem. Our single collection had neither of those properties, but it was found in a Seattle park with birch as one of the many types of nearby trees. Little is known about how to recognize it over here.

 

Russula benwooii

I have saved one of my favourites for last. Normally, when we discover a new species in the PNW, all we are really doing is admitting that our species isn’t really the same as the European mushroom whose name we’ve been using for it, but that enough differences were found to justify separating it out and giving it a different name. That’s not the case here. Arguably the most interesting result to come out of Ben’s study was that one very, very common Russula, found at least 60 times (second only to how often R. mordax was found) was something completely different than expected. This Russula was large, and kind of looked like R. xerampelina and R. vinosa, and was always mistaken for one of those two. Did it smell like shrimp or turn green in FeSO4? No, and anybody spending just a few seconds to try those things during the hundreds of times it has been collected would have noticed it was not a shrimp Russula like they thought. But when you’re finding them by the hundreds, who has time to test every one? You just start assuming you’re looking at yet another one. Anybody who thought it was R. vinosa could have dispelled that myth quickly by scratching it and noting that it did not change colour, but sometimes it has a faint grey tinge to the stem and if you don’t look too closely, you could imagine it was probably a greying reaction happening, and not bother to spend any more time on it.

Thus this Russula, not closely related to any known Russula that was ever rumoured to exist in the PNW, went unnoticed for decades. I’m just as guilty as everyone else for not looking closely at it but dismissing it as one of the two other unrelated species. It may be closely related and is similar to R. paludosa from Europe, but nobody ever suspected that mushroom might be here. As soon as I heard of this cool discovery from Anna’s study of Ben’s collection, I advocated for naming it after him, which finally happened in late 2017. It is a large Russula, easily reaching 10cm. The cap colours can of course be variable, but are often brownish-tan maybe with areas of olive and darker spots of red or purple. The stem may be purple flushed (like R. xerampelina) perhaps with a faint greyish tint (as if it is greying like R. vinosa), both also large species, which it has traditionally been mistaken for. In one Alaskan collection, the purple flush on the stem was significant.

Russula benwooii © Ben Woo

R. viridofusca (in the xerampelina group of shrimp Russulas) on the left, with the stem turning green in FeSO4.

R. vinosa in the middle, with the stem turning grey where scratched.

R. benwooii on the right, with the stem not changing colour when scratched and turning the ordinary rust colour of iron in FeSO4 instead of green.

Photos © Danny Miller

 

Unsolved Russula mysteries

If you are thinking that we should pay close attention to other Russula species described by Burlingham in 1936, you’re right. There are others, whose identities are not yet understood. R. placita (a hot purple Russula), R. murina (slowly slightly hot olive-grey Russula) and R. inconstans (slowly slightly hot Russula with a red margin and yellow-brown center). Also there is R. maxima (a large, mild, purple Russula with a rose coloured stem) described by her in 1915. Very little is known about these species except they are likely somewhere in this “crown clade” and microscopically, do not match any known species enough to suggest what they might be. Absent sequences of the types and further study, they will remain a mystery.

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