In 1996 I was working at Forest Research in Rotorua when Jack Simpson, a visiting Australian mycologist, pointed to a mushroom under silver birch and asked: “what’s that?” Like most New Zealand mycologist, I said birch bolete (Leccinum scabrum). He looked at me quizzically, the way that only Jack does, and said: “Is it?” The stem flesh turned blue when exposed to air. All of the descriptions of Leccinum scabrum say the flesh is unchanging and certainly does not blue.
The only scientific description of New Zealand specimens of this bolete was by McNabb (1968). However, it was the illustration by Marie Taylor in 1970 that set the idea that this fungus was Leccinum scabrum firmly in the minds of New Zealanders. From 1970 on it just was and no one questioned the identification again.
From Taylor (1970)
In response to Jack’s question, I collected more boletes within 30 meters of the original question site from under 15-20-year-old European silver birches. I got that same strong clear blueing that Jack and I saw in the first collection, which then fades to a blue-green. On this evidence, it is clearly not Leccinum scabum. So did McNabb, who described the flesh as “flesh sordid white, unchanging on exposure to air”, not see the blue discolouration or are we dealing with two species under birch in New Zealand?
Di Batchelor sent me two photos of boletes she had collected from under birch in the Wairarapa. The second photo clearly shows blueing in the insect holes at the base of the stem.
Specimen 1 (photo Di Batchelor)
Specimen 2, note bluing at base of stipe (photo Di Batchelor)
I asked Di if there had been blueing of the stipe tissue when she cut it lengthwise. She noted a strong blueing in the lower stipe that developed of a number of hours. She also said that there was no reaction at all in the first specimen. So this begs the question of whether blueing is not consistent from collection to collection or these two photos represent two species.
Specimen 2 cut length wise, note bluing in lower stipe (photo Di Batchelor)
The collection that I looked at from Rotorua differed from McNabb’s description in that he described the “cuticle composed of filamentous, repent, septate hyphae” whereas I found it to be an intricate trichoderm. This could just reflect development stages of the fruitbodies that I looked at. I also found that the basidiospores were bigger than any described species in the section Scabra and that the caulocystidia did not match McNabb’s description.
I have attempted to key the New Zealand bolete out in the Leccinum keys of Smith, Thiers and Watlings (1967), Kibby (2000), Noordeloos (2009), and Persson (1992) but it just doesn’t fit any of the species. So at this stage, all I can say is that we may have Leccinum scabrum but we certainly have another Leccinum species as well.
Kibby G 2000. A user-friendly key to the genus Leccinum in Great Britain. Field Mycologist 1: 20-29.
McNabb RFR 1968. The Boletaceae of New Zealand. New Zealand Journal of Botany 6: 137-176 + 3 plates.
Noordeloos ME 2009.The genus Leccinum in Western and Central Europe. http://www.entoloma.nl/html/leccinum_eng.html [This is no longer available 10.04.2020]
Persson O 1992. Leccinum S.F. Gray. In Hansen L, Knudsen H 1992. Nordic macromycetes, volume 2,: Polyporales, Boletales, Agaricales, Russulales. Nordsvamp. Pp.63-66.
Taylor M 1970. Mushrooms and toadstools of New Zealand. Wellington, AH and AW Reed Ltd.
Smith AH, Thiers HD, Watling R 1967. A preliminary account of the North American species of Leccinum, sections Luteoscabra and Scabra. Michigan Botanist 6: 107-154
Spores, moulds, and fungi 
Leccinum Versipelle
http://www.first-nature.com/fungi/leccinum-versipelle.php
The problem is that the characteristics are not consistent so are we dealing with one species or more. Specimen one above has a similar dark colouring as Leccinum versipelle but did not blue as should be expected. Where as the second specimen looks like Leccinum scabrum but blued when it shouldn’t!
Yes. I would guess Leccinum scabum for the first specimen. Although the cap colour is unusual for scabum it could be that particular environmental conditions have produced the discolouration. Whereas the cap of versipelle is know to vary significantly. I am unaware of other species that resemble these specimens that would grow under birch trees. As a disclaimer I must admit that I am hardly qualified to assert the identification.
Hey I collected some birch bolettes under a tree outside my sons house
in fairfeild, lower hutt. resembles those in the first picture, tree was a silver birch, apparently they’re edible, being a chef I’m keen to try them – no bluing on the stem they’re dried now . Posted a pic on nature watch I would be greatful for any advice
cheers Liam
Hi Liam
I have looked on Nature Watch but cannot find any picture of birch boletes from your area. Can you post a link.
Thanks, Geoff
what’s your call on the birch bolete that do blue? edible? we are already having a bumper crop in Wellington – running out of freezer space already – what’s the best drying method?
Hi NicC
People have been eating this species believing it was birch bolete and as far as I am aware without ill effect. I dry all my mushrooms using a food dehydrator see https://sporesmouldsandfungi.wordpress.com/2012/05/26/this-way-up/
Another method is to cut them up and lay them on a rack in the oven set to a very low heat and the oven door ajar to let out the moisture. If you have a fan oven they would probably dry faster. The idea is not to let them sweat in their own steam. Also they need to be totally dry or they will go mould when you package them up and the packing needs to be airtight as they quickly absorb moisture from the air and go mouldy.
Cheers
Geoff
Hi, any update on what you think the blue staining ones might be? I saw an entry on the Landcare Research database about Boletus leptospermi that says it bruises blue when exposed to air?
Bluing occurs in species across many genera of boletes – for instance see Tylopilus brunneus https://sporesmouldsandfungi.wordpress.com/2014/05/04/bolton-street-memorial-park-2/
I don’t know when the identity of our birch bolete will be resolved but it won’t be until the species in Europe are better resolved.
Cheers
Geoff
Only 4-8 years too late, BUT.. I’m pretty sure I used to find (and eat) the blue-staining birch boletes in Palmie North back when I was first getting into mushrooms. However, the birch boletes around the tree near our house are definitely not blue-stainers. I guess DNA sequences would be the simplest way to categorically determine if they’re different species or not. If anyone finds some of the blue-staining one and wants to send a sample to me, I’ll see what I can do..
I collected some today in Wellington from a new-to-me spot beneath a birch tree. They look pretty much identical to the non-blue staining ones, except of course when cut. The stems have a slight bluing, the caps don’t seem to stain at all.
I’d be happy to send you some, but lock-down presents a problem! I’ve taken a few photos What would be the best way of preserving them in the meantime?
Hi Paul. Can I ask where you found them? You can email me on sporesmouldsandfungi@gmail.com If its within walking distance I could collect some.
I still have the dried ones I collected during the first lockdown if you are interested. I could post them or drop them off to you.
I have just found some blue stained bolete under our birch trees yesterday. Earlier this season there were only the larger and not blueing Leccinum scabrum. Was thinking these ones are more consistent with Leccinum cyanaobacileucum. Taihape area.
Hi Christina. I’m not saying its impossible but there are no records of Leccinum cyaneobasileucum in New Zealand. Did you take any photos or keep a specimen? Cheers Geoff
Yes I did take photos.
The bases had no blue at all, only some blue on the lower and middle parts of the stems. One of the stems had blue in 2/3rds of the stem when cut in half. One day later some of the blue has a greenish hue and in another almost gone so I am guessing the blue could be from damage or mould? The poplar bolete, Leccinum duriusculum is said to often tinge blue near the base. I’m a novice really and just trying to identify the mushrooms on our property.
Hi Austen, It has been a while since I have given this much thought. I to reread the blog to remind me, 🙂 DNA sequencing would probably resolve the problem. I now work at Manaaki Whenua we have the capability but I have neglected to do it.
Comedically, I made essentially the same comment on another post (#3 maybe) 8 years ago!?! Which proves that my goldfish bowl memory is 8 years (or less)..
I did a bit of digging, and the blueing version sounds quite like this: https://www.first-nature.com/fungi/leccinum-cyaneobasileucum.php – at least at a macroscopic level.. Consistently, I seem to remember that blueing ones I used to find in Palmy were smallish (although some shown here look a decent size)..
So interesting! I ate two small ones as they grew under our birch at home thinking they were regular boletes. I had some kidney pain for a few days after which may or may not have been from them. But it did concern me. And now I feel stupid for eating them.
An interesting follow-up. The recent rains brought some more of these birch boletes out under the same tree as before. I even made a video for my students showing clearly that cutting them produces no blueing reaction. I collected them and trimmed the bases ready for the pan. However, in the evening, several hours later, I noticed that the bases were, unmistakably, BLUE!! In other words, these ARE a blueing species here, just extremely slow to develop.
What is the latest thinking on the bluing Birch mushrooms? I plan to plant some birch trees on my property and want to inoculate them and I want to make sure I get the correct edible mushroom.
Hi Pat, in Europe blueing has traditionally been used a significant character to separate species in a number of genera including Lecchinum. However, molecular analysis does not support many of these separate blueing species and that seems to be the case for birch bolete in Aotearoa New Zealand. They are all considered Leccinum scabrum whether they blue or not. Well at least for the moment. Cheers, Geoff