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Danny’s DNA Discoveries – Lactarius
by Danny Miller
Piperites clade - Other Lactarius
First, a few small species (~5cm caps with stems <1cm thick) that somewhat resemble the Russularia, but not as orange.
Lactarius glyciosmus group
Small, grey to lilac-grey, not uncommon European birch species that smells strongly of coconut! There are 2 sets of sequences, 6bp apart, both found on both continents. One is found in Sweden (the type area) and interior BC so far. The second is found in Italy, Alaska, northern BC and WA.
Lactarius glyciosmus group © Steve Trudell
This small, common, dark brownish-grey capped and stemmed conifer mushroom described from Oregon has beautifully contrasting white gills, making for a lovely colour combination. It is extremely slippery all over. Its relatives, like L. kauffmanii below, are stockier and might be recognized by having a slight stem stickiness.
Lactarius pseudomucidus © Kit Scates Barnhart
This dull brown to olive-brown capped species is probably a Russularia based on microscopy, but we don't have its DNA yet. It might not be recognized as a Russularia because it often is lacking the orange tones that characterize the candy cap relatives. It is not uncommonly found under alder, described from Washington. It has a mild taste.
Lactarius occidentalis © Michael Beug
Lactarius lepidotus is a rare, similar Piperites drab little grey-brown mushroom found only at Mt. Rainier under alder so far. It has a scaly cap. We need collections to analyze. Mushrooms that look like this from France have been photographed and/or sequenced, but nothing local yet.
Lactarius alpinus var mitis, discussed in the Russularia, may not be in the Russularia but perhaps here in the Piperites.
The rest of the species are stockier, with caps up to 10cm or so and stems often >1cm thick
This common European conifer species is a member of Russularia but can get so large you might not look for it in that group of usually small mushrooms. It is a brick reddish colour, but most importantly is exceedingly hot tasting and might be identified on that basis alone, if you're brave enough to try it.
Lactarius rufus © Steve Trudell
Lactarius hysginus - be on the lookout for this rare, reddish brown capped Lactarius from Europe, probably in the Piperites, reported to occur here but with no proof. There is a L. hysginus var americanus from California also reported to occur in the PNW but I have no idea if it represents the same mushroom, a distinct variety, or should be its own species. We need sampling.
Lactarius 'necator' - my favourite beautifully ugly toadstool, dingy dark greenish with orange or other colours mixed in. The colouration is unmistakable. It is a relatively common European mushroom that grows with birch. There may be more than one related species and it isn't clear that ours is the actual L. necator, but there's a good chance it is. This species has also gone by the name Lactarius turpis.
Lactarius olivaceoumbrinus - almost identical looking local west coast conifer species described from Mt. Rainier, WA. As well as being found with different trees, its milk may slowly stain green! It may also be common, but since they're so hard to tell apart, I don't know which is more common.
Lactarius sordidus - a third similar, rare conifer species, also not necessarily closely related, from the east coast rumoured from Idaho, but we have no DNA confirmation yet of what this species actually is. It is more yellow-green.
Lactarius necator and olivaceoumbrinus © Steve Trudell, L. sordidus © R. Lebeuf
Lactarius pubescens var betulae
It is not uncommonly found under birch, with a pale cap with hints of pinkish-orange and a bearded margin (but not with a scrobiculate stem).
This eastern North American variety differs from the European L. pubescens by milk that might slowly stain yellow, but there is no obvious genetic difference between our countries. DNA within Europe varies by a couple of base pairs, and our local material varies a couple of base pairs from that, so there seems to be no geographical pattern. It may be proper to just call our mushroom L. pubescens, unless it can be determined that some other characters separate the specimens that stain yellow. (Local collections may or may not exhibit this character).
Lactarius pubescens © Danny Miller
Lactarius torminosus var nordmanensis
The rare Eureopean species L. torminosus has a bit more pigment (darker pinkish-orange) and some zonation on the cap. But otherwise it is a similar bearded species found under birch and sometimes other hardwoods. DNA so far has been found in the BC north and interior. It is reported from Idaho.
The rare L. torminosus var nordmanensis, described from Idaho, differes from the European L. torminosus by milk that might slowly stain yellow, but there is again little genetic difference between the continents (and < 0.5% difference between them all) so our mushroom may properly be called L. torminosus.
There is, however, a sequence from near Victoria, BC that is unique and could represent a new or different variety or species. We need more collections and a type sequence for var nordmanensis to know the answer.
Lactarius torminosus © Debbie Viess
An orange, zoned cap that is bearded, with a scrobiculate stem. It is a rare southern species described from CA and also found in southern OR. DNA from Oregon is 3bp and 3 indels different than DNA from California, plus DNA of a sister species was found in Oregon, so we need to investigate if this is a species complex.
Lactarius subvillosus © Christian Schwarz
Lactarius olympianus (zonarioides)
This orange, zoned capped species is not bearded and has a white stem. It is a more common conifer species throughout the PNW. Our local species, L. olympianus, described in 1979 from the Washington Olympic coast, appears to have DNA identical to the 1953 European species L. zonarioides, so that older name would take precedence. When describing L. olympianus, Hesler & Smith realized that it was possibly the same mushroom as L. zonarioides, but there was some confusion as to what mushroom L. zonarioides refers to, so to be on the safe side, they gave it a new name anyway. If the confusion is ever resolved, it may turn out that a more proper name is L. zonarioides.
Lactarius olympianus © Andrew Parker
This mushrooms is related to the quickly yellow staining milk species, although its milk only stains slowly. It is a yellowish capped species that may or may not be zoned that is not bearded and the stem is slightly scrobiculate. It can be confused with L. olympianus above if the cap is especially orangish and the scrobiculation is not pronounced. It can more easily be confused with L. scrobiculatus and L. resimus (when somewhat bearded and scrobiculate), as demonstrated by the fact that sequences of L. resimus have been called L. alnicola and sequences of L. alnicola have been called L. scrobiculatus, but those species' milk turns yellow much faster. Although named after alder (alnicola means "alder loving"), it can be found with both hardwood and conifer trees. It is pretty rare, mostly restricted to the eastern and southern parts of the PNW (the type is from Idaho).
I think I have DNA of this species from Idaho, but I'm not sure, so more samples would be appreciated. We also have local DNA of up to three additional unnamed species in the L. resimus/alnicola/scrobiculatus clade, that need to be studied more to see if we have more species in this group.
Lactarius alnicola © Noah Siegel
Not much is known about this rare Idaho species found with spruce, fir with alder and aspen present. It is apparently sticky capped, pale olive-buff with coarse hairs around the margin that darken in age, very acrid, the milk stains the gills dark and the white stem with ochre spots stains dark yellow-brown on handling.
This is a rare, northern, grey, European birch species with milk that turns grey and stains the gills grey. Formerly only reported in the west from CO and ID, but the DNA keeps turning up in BC. We need a photo of a verified specimen.
probable Lactarius vietus © Buck McAdoo
Large, pale species
This is a large (~15cm) white Lactarius with pink gills, that resembles Russula brevipes and Hygrophorus saxatillis unless you notice the latex. It is uncommon and found with cottonwood, aspen and willow. North American DNA is about 1% different than European DNA (6bp), so it may be that our species gets a new name in the future.
Lactarius 'controversus' © Ben Woo
A similar conifer large, whitish Lactarius with perhaps a slightly bearded margin, no stem strobiculation and without the pink gills. It could be confused with L. alnicola but that species has a somewhat strobiculate stem and latex that may slowly stain the gills yellow, while this species may stain them brown.
We have the type sequence from Washington, but no colour photos of confirmed collections, so we need more collections to understand how to recognize it.
possible Lactarius pseudodeceptivus? © Michael Beug
Lactarius argillaceifolius var megacarpus
Another large Lactarius, this one very large (may be 20cm or more). It is rare, only found in southern OR and CA under oak. It has a purple-grey cap and the gills stain brown (no beard, no scrobiculation). We need DNA of this variety, and as there is no consensus of what the real L. argillaceifolius var argillaceofolis is from the east coast, our specimens do likely represent a true distinct variety if not species.
Lactarius argillaceifolius var megacarpus © Danny Miller
Grey species with viscid stems - most need collections and so far don't have DNA records
Our most common grey capped conifer species with a viscid stem, larger than L. pseudomucidus, stem paler than cap, described from Idaho. It is unknown if L. kauffmanii var sitchensis from Oregon, growing under spruce with creamy yellow spores instead of white spores, is distinct or not.
Lactarius kauffmanii © Steve Trudell
L. mucidus - similar to L. kauffmanii, but smaller, perhaps with a pale cap margin, the milk staining the gills yellow or green. Two east coast varieties have been reported from the PNW and need confirmation by DNA. It is expected that all of these species will be genetically closely related.
L. caespitosus - also in the L. kauffmanii species group, described from Wyoming, with a buff spore print. We do not have DNA of this yet either.
L. glutigriseus - another group member described from Alaksa under hemlock, with the middle of the stem coloured but the top and bottom pale, also without DNA yet.
All are rare. We have DNA of a couple local, related species in this group without names, but since we don't have official sequences of these species, we don't know how to match them up.
Also with viscid stems, although not always obviously so
A rare, conifer cinnamon orange capped mushroom with a cinnamon tinged stem. No zoning. This is an eastern North American species and DNA from interior BC matches DNA from Quebec with 3bp substitutions, so it's reasonable to assume we may have the real species here. We need a photo of a proven collection.
probable Lactarius affinis © Ben Woo
Very closely related, but maybe darker in youth. Rare. DNA exactly matching European DNA was found in northern BC and the species has been reported from ID and WA. Conifers. We need a photo of a proven collection.
We may have found DNA of a third species in this group in the BC interior, mistaken for L. kauffmanii, so more collections are needed.
probable Lactarius trivialis © Andrew Parker
L. flexuosus - rare, greyish brown cap with lilac tones, zoned especially near the margin, and with a tinge of colour in the gills (best seen in the second photo). The stem may not be viscid. With birch and cottonwood. It was not known from the PNW until recent DNA studies which found sequences of it in Washington that differ by only 1 bp and 1 indel. L. pseudoflexuosus, from back east, appears to have similar DNA (an additional 3 bp differences) but our species is a better match for the DNA of L. flexuosus. It looks suspicously like the next species.
Lactarius flexuosus © Buck McAdoo, NAMA and the Field Museum of Natural History
L. circellatus var borealis - also rare, described from Idaho near conifers and birch, this species perhaps has stronger lilac tints. No DNA yet, so we need some to compare with the previous species.
probable Lactarius circellatus var borealis in California © Christian Schwarz
There are isolated, unconfirmed sequences of local DNA of unknown or undescribed species, so we probably don't know the whole picture yet.
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