Observation 219692: Leccinum variicolor Watling

When: 2015-10-18

Collection location: Union, Connecticut, USA [Click for map]

Who: Robert(the 3 foragers) (the3foragers)

Specimen available

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Quote of the language on red staining context and macrochemical reactions.
By: Scott Pavelle (Scott Pavelle)
2017-05-17 12:47:54 CDT (-0400)


A pinkish, sometimes reddish, discoloration of the context is considered to be a diagnostic character for species within subsections Scabra and Leccinum. Smith & Thiers (1971)made a distinction in theirkeys between species in subsection Leccinum that show a pinkish discoloration before turning blackish (like L. aurantiacum sensu Smith & Thiers) and those that do not show a pinkish discoloration, but only a blackish discoloration (like L. insigne>). We found that this pinkish discoloration was often lacking in species that were supposed to have it according to literature and found that usually the European species can be recognized by other, more stable characters. Watling(1970) and Lannoy & Estades (1995) considered the intensity of the pinkish discoloration a distinctive character to distinguish L. scabrum and related species. Leccinum scabrum is supposed to display no or only a slightly pinkish discoloration,while species like L. roseofractum are supposed to show a rapid reddish discoloration.We found samples identified as L.scabrum and L.roseofractum in one clade and could not find any phylogenetic signal that these were two distinct species. Moreover,we found that the intensity of the pinkish discoloration of the context of the accessions in this clade is a gradual one and can therefore not be used as a diagnostic character of any of these species.

A bluish discoloration is present in most species of subsections Leccinum, Fumosa and Scabra, except in L. scabrum and L. rotundifoliae. This blue discoloration is usually found in the cortex of the stipe base and/or in the basal mycelium, though in some species like L. variicolor, it is found in the cortex of the lower half of the stipe. The colour is usually blue (K. & W.23A7) or greenish blue (24A5,25A5). In L. variicolor the greenish blue discoloration usually changes to yellow in dried fruit-bodies, a phenomenon rarely observed in other species of subsection Scabra.The absence of the bluish discoloration is diagnostic for L. scabrum and L. rotundifoliae. However,the bluish discoloration is not always clearly observable and should therefore be used with caution.

Other colour changes of the context, such as yellow and red discolorations in the stipe base and an olivaceous discoloration in the apex of the stipe are variable within species. In particular the olivaceous discoloration in the apex of the stipe seems to be associated either with a wet growing habitat or continuous wet weather. For this reason they are considered of very limited diagnostic value.


Lannoy & Estades (1995) considered the reaction of the context with FeS04 and
Formol to be of importance for the identification of certain species groups.When FeS04 crystals are rubbed against the context of (preferably) the apex of the stipe, a greenIsh grey to blackish discoloration may appear. Formol, when applied to the context, sometimes induces a pinkish to reddish discoloration of the context. The usefulness of FeS04 as a reagent for the identification of species in subsection Scabra has been tested. It was often found to be very gradual, and difficult to assess whether the discoloration was greyish green or greyish. Moreover, there seems to be a relation between age and humidity of the fruit-body and the intensity of the reaction with either formaldehyde or FeS04. Therefore these macrochemical reactions have not been used in the present work.

By: Debbie Viess (amanitarita)
2017-05-17 11:38:16 CDT (-0400)
By: Robert(the 3 foragers) (the3foragers)
2017-05-17 10:21:37 CDT (-0400)

In my Experience snellii is a much smaller mushroom than variicolor for one.
But I think we could differentiate with the mycorrhizal relation. I have to go out and take a closer look in the growing area and observe better. Oh by the way I have a good pH meter.
Debbie can you give us the link where did you find Machiel Noordeloos paper?

By: I. G. Safonov (IGSafonov)
2017-05-17 00:31:52 CDT (-0400)

Maybe the way to separate snellii and variicolor in the field is not by morphology but by mycorrhizal association and ecology/soil chemistry, as den Bakker & Noordeloos suggest. After all, scaber stalks are mycorrhizal specialists, so there’s got to be an observable difference in the habitat between the two in light of the fact they are not closely related. If someone can reliably prove (via DNA) that snellii grows only in alkaline soils and variicolor only in acidic soils in the USA, eventually we can do the ID without peering through a microscope and spending $ on sequencing. Gotta buy one of those soil pH meters.
Robert, what are the habitat and ecology like for 219692/256646?

Well, now that…
By: Dave W (Dave W)
2017-05-16 23:09:58 CDT (-0400)

this snellii/variicolor issue has been cleared up :-) maybe someone could suggest something about this one obs 175374. I IDed this back in the good ’ol days when red/pink above and blue below meant your gray/brown/tan-capped scaber stalk was snellii. The ones seen in 175374 were growing in obvious association with a gray birch (Betula populifolia). I think the blue stain travelling up through most of the stipe context eliminates scabrum from consideration.

What I have called snellii exhibits blue/pink staining with intensity that seems to vary annually.

it’s a very long paper
By: Debbie Viess (amanitarita)
2017-05-16 16:57:44 CDT (-0400)

and I didn’t quote the entire thing.

basically, they are macro identical, other than habitat and some various micro differences, but probably even those aren’t ironclad.

Leccinums are tough to ID, for everyone. Some act like they can. But if you need to run DNA to put a name on your mushroom, maybe that name just isn’t so easy to find? Sure, it’s nice to know what occurs here and what doesn’t and
DNA can tell us that. But then what about the next Leccinum, and the one after that, and the one after that?

DNA costs real money, or someone’s time and good nature. It ain’t free, at any rate. And some of these species breaks might just be a misreading of data.

Let’s have this conversation again in another ten years. I suspect there will be plenty of changes in our understanding.

By: walt sturgeon (Mycowalt)
2017-05-16 15:36:47 CDT (-0400)

I was at the Cain Foray with Den Bakker and we agreed that macroscopically the two are twins. I called it L. snellii and he called it L. variicolor. The species I see in NW Pa. and WV is common in woods with hemlock and yellow birch. The streaked cap is common but not always present.

By: Scott Pavelle (Scott Pavelle)
2017-05-16 15:11:44 CDT (-0400)

…quoting from the Noordeloos paper below:

“There may also be an ecological difference between the two taxa. In the Great Lakes region of Canada the first author generally found L.variicolor in the same habitat as in Europe, viz. in humid, acidic habitats. Leccinum snellii was found only once, and in a completely different habitat, viz. a rich, slightly humid forest on alkaline soil. The locality of the specimens on which the original description of L. snelliiis based can also be interpreted as a rich forest, consisting of beech, maple and yellow birch.”

Aside from that, I am a bear of little brain and must have missed something. Where do they talk about the chemical tests and staining features? Is it in a part of the article that you did not quote? Please remember that I am playing catch-up to all the rest of you, and I’m starting quite a few laps back.

assume that one doesn’t have DNA funding
By: Debbie Viess (amanitarita)
2017-05-16 12:30:14 CDT (-0400)

for every mushroom found.

how would you tell this sp. apart from snellii, considering that chem tests and staining are not reliable features in the separation of Leccinum sp.?

The cited Noordeloos paper discusses staining and chemical rxns. at length.

By: Robert(the 3 foragers) (the3foragers)
2017-05-16 12:10:01 CDT (-0400)

Based on the resent DNA test we now know that this mushroom is L.variicolor.
Match the European data. For the test: Left to right > ammonia,KOH,FeSO4 on the stipe. In the cap flesh bottom to top ammonia,KOH,FeSO4.
No reaction to Ammonia, KOH at all. KOH no reaction to cap, on the stipe flesh and cap flesh made a small indentation, And FeSO4 turns grenish on on the stem and cap flesh. no reaction to cap.

Robert, on the chemical tests.
By: Scott Pavelle (Scott Pavelle)
2017-05-16 11:39:49 CDT (-0400)

I’m looking at the photo and have a little trouble figuring it out. Here’s what I see:

No reaction to anything on the cap.

On the flesh, something turns blue. I’d think FeSO4, but it doesn’t line up with the bottles.

On the flesh, something dug a hole, but only in the cap flesh and not in the stem. I’d think KOH but need confirmation and I am suspicious about the no-reaction in the stem. Please explain.

In general, these are also the results from a single test. Can I count on them enough to publish it on the BF as a description? Or do I need to hedge? Or just dodge it completely by saying the data remains too limited to report? As you know, I’ve had terrible trouble getting my own chemical tests to match up to what’s reported in the books.

Many thanks in advance. And if I didn’t say it before, congratulations to both you and Igor on an important find that really does change the bolete world in a small but genuine way.

Noordeloos also emphasizes the unreliability of staining rxns.
By: Debbie Viess (amanitarita)
2017-05-16 11:39:21 CDT (-0400)

but we already knew that.

snellii and variicolor are essentially identical as well.
By: Debbie Viess (amanitarita)
2017-05-16 11:35:56 CDT (-0400)

but very different in their DNA.

the Noordeloos paper (quoted below) summarizes this nicely.

Going by written data only…
By: Scott Pavelle (Scott Pavelle)
2017-05-16 11:25:14 CDT (-0400)

I just added variicolor to the BF yesterday, using a description published at this website: http://www.first-nature.com/fungi/leccinum-variicolor.php

Comparing that to the data for snellii, the distinctions would be these:

  • variicolor almost always has the mottled cap, while it’s occasional with snellii
  • snellii often has a white band on the upper stem & often has greenish stains on the lower part. Neither are reported for variicolor.
  • snellii flesh reliably stains pink, though slowly, and then eventually resolves to grayish brown. Variicolor may stain pink but not reliably, and there is no report that the staining will resolve to a darker color.
  • Looking at the photos, it also seems that snellii stains a stronger pink/red to begin with.

Both are supposed to be good eats, which is all that really matters. Right? [Ducking and running now!]

NOTE: I emphasize that this is a summary of what I’ve read and not anything based on first hand knowledge. It seems likely that at least some reported versions of snellii are actually variicolor, which wasn’t supposed to be on this continent. It’s also possible that the two are actually identical (has anyone checked on this?) and that snellii also occurs in Europe, where it has been assumed to be a North American-only species.

I hope this helps.

specific leccinum IDs
By: Debbie Viess (amanitarita)
2017-05-16 10:45:26 CDT (-0400)

are a nightmare in the best of circumstances.

but these do have some good variicolor characters. apparently there are both habitat and micro differences between variicolor and snellii.

Below is an excerpt from the Noordeloos paper on European Leccinum sp.:

Den Bakker & Noordeloos: A revision of European species of Leccinum, PERSOONIA – Vol. 18, Part 4, 2005, pgs. 568-560.

“Leccinum variicolor can be easily recognized in the field on account of its variegated pileus and distinct blue-green discoloration of the context of the stipe.
This species occurs in North America and could even be locally common, given the fact that the first author observed that this was one of the most common species ofthe subsection Scabra at the Cain Foray (Mycological Society of Toronto) near Huntsville (Ontario,Canada) and on Manitoulin Island(Ontario,Canada) in the fall of 2003. It has long been unnoticed because it has been confused with L. snellii. Both species have a similar discoloration of the context, and also the septate caulocystidia, that were thought to be diagnostic for L. snellii (Smith et al., 1967) are found in L. variicolor. Molecu- lardy, however, the two species cannot even be considered closely related (DenBakker et al., in prep.). Based on a limited number of herbarium collections and the original description of L.snellii, the most important differences are found in the pileipellis, in particular in the shape of the terminal elements.The pileipellis ofL. snelliiis characterized by the presence of 8- 10 ptm broad cylindrical elements and clavatetoconical, terminal elements with dark brown vacuolar pigment. The pileipellis of L. variicolor is also characterized by the presence of short, cylindrical hyphal elements,but usually they are less broad (4.5- 9.0/on) and the terminal elements are conical. In particular the clavate terminal elements are distinctive for L. snellii, and have never been found in L. variicolor. There may also be an ecological difference between the two taxa. In the Great Lakes region of Canada the first author generally found L.variicolor in the same habitat as in Europe, viz. in humid, acidic habitats. Leccinum snellii was found only once, and in a completely different habitat, viz. a rich, slightly humid forest on alkaline soil. The locality of the specimens on which the original description of L. snelliiis based can also be interpreted as a rich forest, consisting of beech, maple and yellow birch. More study is needed to understand the morphological delimitation of these two species.
Lannoy & Estades (1995) recognized three infraspecific taxa within L.variicolor, viz. var. bertauxii differing from var. variicolorby an evenly coloured blackish pileus and the absence of pinkish discolorations of the context in stipe and pileus, f. atrostellatum, differing from the typical form by a dark star-shaped pattern on the pileus, and f. sphagnorum, a form with uniformly coloured brownish pileus. Since all these character states fall within the normal range of variability of L. variicolor examined during this study, these taxa are not considered of taxonomic value.”

By: walt sturgeon (Mycowalt)
2017-05-16 10:34:38 CDT (-0400)

How does this differ from Leccinum snellii?

Robert? There is no description here at all…
By: Scott Pavelle (Scott Pavelle)
2017-05-16 08:49:54 CDT (-0400)

Let alone the chemical tests.

P.S. Vote on the I.D. based on DNA results.

Created: 2015-10-18 17:57:46 CDT (-0400)
Last modified: 2017-05-17 10:26:07 CDT (-0400)
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