It's a Bird! It's a Plane! No, It's Pyrenomyxa picea! – A Yearslong Mystery Solved

 

February 6, 2016

I'll set the stage: It's almost eight years ago. I'm in the woods with the dog, slogging through deep snow, looking for whatever I can find. Winter is actually a great time to discover all kinds of obscure stuff you might otherwise miss in the summer and fall when it's easy to be distracted by all the flashy fleshy fungi that proliferate in those warmer months. 

Ontario winter with Ruby

I see it from a distance on the bare trunk of a standing dead aspen, a vibrant rust-coloured stain that contrasts sharply with the near monochrome of the winter woods. I see, too, an Armillaria's black mycelial cords knotted around the pale trunk like macramé – remnants of the mushroom that was almost certainly responsible for the tree's death.

Bright rust-red stains

Almost there (it's slow going) and I can see that there are elongated dark and gnarly lumps attached to the reddish stains. 

At this point, I'm pretty sure I've been hoodwinked into making a beeline for a string of raccoon or fisher turds that are somehow stuck to the side of the tree; I have been tricked by poop before.

What the hey?

But then I'm right there and, since the lumps are conveniently located at torso level, I can inspect them closely. The rust-red stain is not only on the tree, it has also given the lumps a gorgeous rust-red patina in the crevices of their otherwise polished black exteriors. The lumps also seem devoid of hairs, or insect shells, or berries. Altogether, a bit weird for scat. 

I'm now thinking along the lines of Hypoxylon or Daldinia, hard carbon fungi that have pigments. Or maybe even something related to Camarops petersii, the Dog's Nose Fungus.

Daldinia childiae can sometimes be really lumpy.

Camarops petersii (Dog's Nose Fungus) is also pulvinate in form.

I need to touch one. I don't poke it – just in case I'm wrong about it not being scat – I just gently touch it. It immediately collapses, its shell cracking, my fingertip coming away with a dusting of black spores. Definitely not poop, then. But what the heck is it?

Its hard shell is easily shattered.

The only thing I know of that would behave like this is one of the larger Myxomycetes, or slime moulds, that form aethalia – sessile, pulvinate lumps packed with not much other than hundreds of thousands of spores. Possibly something along the line of Reticularia. Reticularia splendens, and R. lycoperdon, (the False Puffball), both have similarities to my lumps, though their spore masses are brown, not black. 

Reticularia splendens is shiny and dark.

Its larger sister, Reticularia lycoperdon, can sometimes look
as if it's been dipped in aluminum paint. Its outer coating is,
however, always extremely thin and tears rather than cracks.

So maybe some kind of Fuligo, though not Fuligo septica, Dog's Vomit Slime, which is always crusty and never smooth and shiny, but maybe something akin to one of its more defined siblings, like F. leviderma.

The outer crust (peridium) of the slime mould, Fuligo
leviderma, is very thin and easily broken...

 

...and its spores are black. Unlike the mushroom I
found, though, the black spore mass inside Fuligo
is shot with light coloured pseudocapillitium. 

Nothing, though, really fits what I've found, and the pigment, both the staining of the wood and the patina on the cortex is throwing me off. The only thing I can do is take some home but it's impossible to collect an intact sample. This thing is crazy friable and fragile; the tree is not decayed enough to cut into the wood and when I try to slide my knife under a section of one of the lumps to pry it off the tree, its shell shatters into multiple shards and its insides mostly crumble to dust. So that's what I take home with me.

 

Slime Mould or Fungus?

 

Basically, I don't have a clue what this thing is. I don't even know what kingdom it belongs to. Fortunately, though, I have a microscope so I will likely be able to rule out one of two kingdoms fairly quickly: If the spores aren't round, my find is not a slime mould.   

 

And they aren't. Instead, they're dark little finger bananas (or, technically, phaseoliform, elliptic-inequilateral) with a slit down their backs. So my first thought was right – my mushroom is likely to be one of the pyrenomycetous Xylariaceae fungi, like Hypoxylon and Daldinia.  

The dark brown phaseoliform, or bean-shaped, spores.

But there's a problem with this diagnosis. All of the members of this group of flask fungi that I know of release their spores through ostioles – openings in the surface of their sporocarps. Even under magnification, I can't see any of these openings. So how does this mushroom release its spores? 

The spores of Daldinia childiae are released through its pimply
perithecial mouths (ostioles) creating a polka-dotted spore print.

Though textured, the outer surface of my find is devoid of ostioles.  

It seems to me that perhaps the spores are meant to be released passively after the outer shell breaks down, the same way the slime moulds mentioned above do. There does seem to be some kind of fibrous structure near the base, but it is in such bad shape it's impossible to tell what the structure might have been before it collapsed. 

I spend the next couple of days going through my books and searching on line for clues as to what my fungus is, but I get nowhere. I'm stumped. So I post it on Facebook's Ascomycetes of the World group, begging for an ID. I get no answers. I dry my specimen and file it away.

Fast Forward a Couple of Years

 Somewhere, I see a photograph of Camillea tinctor. I get all excited because a) like my mushroom, C. tinctor is black and b) it clearly stains the wood beneath its sporocarp a bright rust-orange. Could this be my mushroom?

Camillea tinctor is a hard carbon fungus that stains the
wood beneath it a bright rust-red. (courtesy Tom Bigelow)

Close, but no cigar. Though the wood staining is impressive, C. tinctor is fairly flat, very hard and has papillate ostioles. Sigh. It's also not found anywhere near where I live in southeastern Ontario. It is, however, common in the New York City area, though it was not reported there until 2016 when Ethan Crenson noticed its proclivity to wood dyeing, which its better-known sister, C. punctulata (which has puctate ostioles) cannot do. The farthest north it has been found since then is just south of Albany, New York. If you find this mushroom, please post it to iNaturalist so that its range can be tracked!

 

Fast Forward to Two Weeks Ago: Serendipidy

 So then the most fun thing happens. I'm rummaging through my Facebook groups and suddenly, there it is, my mushroom! At first I even think I'm looking at my photographs, but no, it's someone else's find, David Chapados's. His look just like mine. I immediately post a picture of my seven-year-old observation. David has already suggested Hypoxylon. There is discussion and other guesses from the experts: Camarops, Daldinia, and yes, maybe a slime mould such as Reticularia. None of these make sense to David any more than they made sense to me almost eight years earlier. Still no one is coming up wih a name. What a buzzkill. 

David Chapados's observation from Quebec.

But here's the serendipidy part: Six days later, someone – a mushroom angel – spurred on by the mystery, pokes and prods iNaturalist until she finds the answer. After starting her search with “Xylariaceae,” which gets 38,000 North American hits, or a few too many to wade through, she tries paring it down to "Pyrenomycetes" which, in its full form, frustratingly links back to the more general “Higher Ascomycetes” with about half a million useless hits. But below that she sees something that catches her interest: a genus called Pyrenomyxa. Knowing that David and others think the mushroom has similarities to slime moulds, or “myxos” as some of us call them, she clicks on the single species and – ta da! – there’s Garrett Taylor’s observation of Pyrenomyxa picea. Clearly the same mushroom. And we have a name! Thank you, Hélène Lafond!

The Name's the Thing

Naturally, this gets me doing the mushroom name dance. Names can sometimes be incredibly hard to find, especially if you're an amateur, so a bit of celebration should be expected. When I've stopped dancing, I start reading about my mushroom on line.

Of course Pyrenomyxa picea isn't its first name. It's a big enough entity that J. B. Ellis found and described it 135 years ago, naming it Hypoxylon piceum (didn't we all say Hypoxylon at some point?). Then, in 1977, it turned into Pulveria porrecta (Malloch & Rogerson, 1977). And now, with a very distinct nod to this weirdo's resemblence to some of the slime molds (Myxomycetes), it has perhaps been given its final name, Pyrenomyxa picea (Stadler, Læssøe, & Vasilyeva, 2005) – the picea/piceum part of its epithet obviously based on it eventually turning "pitch black," (which, for those born more recently than me, means "black as tar"), and not having any relationship at all to spruce trees since it's known only from angiosperms.

It's definitely an oddball. Its habit is to form under the bark of dead trees, (the bark on my tree had recently fallen off) so actively ejecting its spores out of its asci would be a waste of time and energy so it has no apical spores or plugs at all. Also, peculiarly, these cleistothecial* asci are produced along "ascogenous hyphae" (see illustration below). I particularly love the way the 8 spores in each almost spherical ascus are nested together like the segments of a clementine. 

The crazy reproductive elements of Pyrenomyxa
picea from the Malloch & Rogerson paper.

Yellow-green KOH-extractable pigment

David Chapados's beautiful cross-section

The only thing missing is that there are no mentions in the descriptions of this mushroom about the striking rust-red colouration of the surrounding wood and the crevices of the sporocarps that is so dominant in my observation, David Chapados's observation, and also in my friend Garrett Taylor's 4-year-old observation on iNaturalist. 

Maybe David Malloch, who co-wrote the 1977 paper, will have some insight. He replies to my email query immediately and says that though he had actually followed the growth of his P. picea over several months, its sporocarps, though reddish-brown when they first appeared, had no such colour later on. So that part remains a mystery. 

Malloch also says that even though it's "kind of a monster fungus once it starts developing," it seems uncommon. I spend a couple of days on iNaturalist trying to determine how uncommon it is by scouring through several thousand images of Daldinia, Hypoxylon, Kretzschmaria, and Reticularia to see if I can find any over-looked observations in northeastern North America. And I do! Not a lot – but a couple that are unmistakably this mushroom. These and a couple of other possible ones make it clear that this is a) not common and, b) a late season organism: all of the observations were made in October or November.  

As I write this, it just so happens to be late season. So this is a good time to go hunting for this special mushroom. Look for standing dead hardwood trees (poplar, ash, maple) with loose bark. For a full description, Mycoquebec has already made a page for it with one of David Chapados's photogaphs. If you do find it, please post it on iNaturalist or Mushroom Observer!

*cleistothecial - from cleistothecium, a globose, completely enclosed fruit body with no special opening to the outside. Like truffles.

References

Malloch, David W and Clark T. Rogerson. “Pulveria, a new genus of Xylariaceae (Ascomycetes).” Canadian Journal of Botany 55 (1977): 1505-1509.

Stadler M, Laessøe T, Vasilyeva L. The genus Pyrenomyxa and its affinities to othercleistocarpous Hypoxyloideae as inferred from morphological and chemicaltraits. Mycologia. 2005 Sep-Oct;97(5):1129-39.

 New Brunswick Museum's Xylariomycetidae Page

Garrett Taylor's iNaturalist Pyrenomyxa picea observation

Mycoquebec's Pyrenomyx picea page

My iNaturalist Pyrenomyxa picea observation where I have copied links to other observations I am either sure are the same mushroom or ones that I think might be.

Jumping Jiminy! It's Spore-eating Snow Flea Season!

Snow fleas look like hopping black specks 
in the snow (Rolf Schlangenhaft)

Though there's still two feet of snow covering the forest floor, there are signs everywhere that spring is on its way. Chickadees have started singing their mating song! The warm sun is tatting lace into south-facing snowbanks! And sunny depressions and ruts in the snow are liberally sprinkled with black pepper! But, wait a second...why would there be black pepper on the snow? And why is that black pepper JUMPING??

Close-up, tiny snow fleas have a blueish cast. 

The first time I found these leaping blackish blue dots in the snow, I had no clue what they were, so I called them snow fleas—which it turns out is what everybody else calls them, from Russia to Sweden to France— though they're not even remotely related to fleas. What they are is a very interesting type of springtail. 

Springtails are very cute little guys that, though they have six legs like insects, are nonetheless different enough that they're not included in that class: among other little quirks, they have fewer abdominal segments, lack proper compound eyes, and shed their exoskeletons throughout their lives. They also have a special way way of jumping. 

Sminthuridae springtails are even cuter 
than snow fleas (Tim Evison/Wikipedia)

Almost all springtails have a tail-like appendage on their abdomen called a furcula. This little device—the biggest springtails themselves are only 3mm long—is folded under the creature's belly and held there under tension by another structure called a retinaculum. When this click mechanism is triggered and the furcula snaps against whatever a springtail is sitting on—be it twig or fallen leaf or crust of snow—the tiny little guy is flung into the air. Kind of like the action of an old tin click toy. This makes it fun to poke your finger into a clutch of snow fleas, which makes them all trigger their devices at once. 

Remember these?

Sadly, springtails have no aiming ability, so they don't have much choice in the direction they go, but the quick random "boings" can be enough to keep them out of the mouths of predators.

Springtails are mini garburators that help to make soil by eating decaying organic matter, algae, fungi and fungi spores, and poop—which is sometimes their own. Thousands can be rummaging though the moist forest floor litter at your feet, but are usually not noticed because they're so incredibly tiny.

In the winter, snow fleas eat spores that accumulate on the surface of melting snow. Spore pickings are rich in the winter since there are many species of fungi that are not only cold tolerant, but that actually thrive in the winter and produce spores when temperatures rise a bit above freezing. These include numerous perennial polypores, resupinate crust fungi, and jellies.

Snow fleas chowing down on Fomes fomentarius spores in January.

No one knows exactly why snow fleas creep up through melting channels in snow to the surface on warm days at the end of winter, but the fact that these minute "cold-blooded" creatures are capable of such activity in cold temperatures when other over-wintering insects remain dormant has interested researchers for a long time.

Thousands of snow fleas in tire ruts in snow... 

...or in crevices. (both photos Rolf Schlangenhaft)

A couple of these researchers, Laurie Graham and Peter Davies of Queen's University have isolated a protein from snow fleas that acts like antifreeze in their bodies. Though there are a number of different animals that have evolved proteins that protect their tissues against the nasty effects of freezing, including the woolly bear caterpillar and the grey tree frog, two characters featured in my kids' book, Winter's Coming: A Story of Seasonal Change  about animals preparing for winter, the protein found in snow fleas, has a novel, and possibly very useful characteristic that other animal "antifreezes" don't have: at higher temperatures they break down. The exciting possibility is that this protein might be of use for organ transplants, which could not only be kept colder, and therefore stored longer than they can be now, but also, when the organ is finally used, the protein will be cleared from a patient's before harmful antibodies can form.  

When there's no snow, snow fleas can be found in forest litter.

Reference

Graham, L.A. and Davies, P.L. (2005) Glycine-rich antifreeze proteins from snow fleas. Science 310, 461.

Recommended

Andy Murray's awesome website A Chaos of Delight features tons of glorious springtails from around the world as well as all kinds of other weird and wonderful tiny critters that lurk on fungi, in soil and forest floor detritus and under logs and rocks.

Ode to a Mushroom (and to Wrinkled Mushrooms and Vernal Ponds): Bolbitius callisteus (B. callistus)

Bolbitius callisteus - baby & young adult

Bolbitius callisteus, a.k.a. B. callistus, is one of my favourite mushrooms – for a whole bunch of reasons. And edibility is not one of them.

Reason #1:

It's a trickster, in that it looks completely different at different stages of its existence. It starts out as a greenish button, with pale greenish yellow gills, then spreads into a licked butterscotch candy parasol – often the same day. If you find representatives of these different stages in different locations on different days, which seems to be the norm since they often grow solo, you'd be hard pressed to consider them to be the same character. At least, I was. 

Young gills with green tones 

Even the stem of the young one has greenish-blue tones, 
tones that can disappear in a matter of hours.

Licked-candy stage

It soon becomes heavily striate.

The caps of old specimens become conical. The stipe 
also darkens, as do the gills as they're 
coloured by reddish brown spores.

In the plant world, coltsfoot is a classic example of such trickery, though this wildflower/herb takes it a step further – or maybe backwards. First it produces dandelionish flowers that push up from the ground in early spring without any sign of accompanying leaves. Only later, after the flowers have withered away, do the oversized leaves finally break through the soil and unfurl. An old name for it was actually Filius ante patrem – son before father.

Since Coltsfoot (Tussilago farfara) flowers and leaves appear at
separate times, you'd be forgiven if you thought they were two
different species. (Photos: left Andreas Trepte, right Wikipedia)

Reason #2:

Bolbitius callisteus has an affinity for growing on fallen hardwood limbs and branches that have been water saturated for part of the year. The best place to find these branches is in vernal pond areas. 

Vernal ponds are spring ponds, fed by snowmelt and rain, but without any outflow. I'm fond of these ponds and the dips in the forest that are revealed when the water evaporates or soaks in. They're the chameleons of the forest ecosystem. In April, they're like any other spring pond, attracting ducks during migration. In May they're all quacky – not with ducks, but with the mating calls of wood frogs. Because these ponds usually appear in low, poorly drained areas, the soil has a tendency to remain moist long after visible water has disappeared. Even during droughts – which are becoming more and more common in southern Ontario – these areas continue to produce fruiting fungi.  

Vernal pond in April

Vernal pond in early March after a dry winter

A different March vernal pond

Vernal pond in May

Vernal pond in June

Centre of a large vernal pond in September (with leaping Ruby)

Vernal pond in October – note the 
spring waterline on the tree trunks

Reason #3

Bolbitius callisteus is supposed to be very rare. Asterotus/Resupinatus dealbutus, which I wrote about a couple of months ago, was also found in vernal pond areas and is also rare. I like finding "rare" fungi since they usually don't show up in field guides, which makes them a challenge to identify. Dried up vernal ponds are a great place to look for rarities. Here's a selection of my local ones: 

The aforementioned Asterotus/
Resupinatus dealbatus that has its own post.

Arrhenia retiruga. The middle specimen is upside
down, showing its gill-less fertile surface.

Clavaria rosea – the subject of my first, very dull, blog post

Hygrocybe coccineocrenata ss. auct. amer. 

Caulorhiza hygrophoroides, which has a long
pseudo-root – so long that I couldn't get all of it.

Baeospora myriadophylla

I question, though, whether these fungi are actually really rare, or simply rarely collected. Human-made paths normally, and sensibly, skirt around seasonally flooded areas, so maybe these areas are just not as frequently scoured by collectors. They can be certainly be unappealing areas when prickly ash is involved (I have thorn scars to prove it).

Reason #4 

I have a soft spot for wrinkles and reticulation, and not only on mushrooms. I have always loved the wrinkles of my straightened elbow, and of the straightened elbows of people I love. So pliable! So playable! So hard to see (on myself)! And the caps of Bolbitius callisteus, when young, are wrinkled and/or reticulate (netted or veined).

Bolbitius casteneus is wrinkled, though often not spectacularly so. 

Fungal wrinkles and reticulation are not uncommon. Lots of boletes, including a number of choice ones, have reticulation on their stipes that can help in their identification. 

Boletus chippewaensis, my local King Bolete, can
have anything from a light netting at the very top of its stem
to head-to-toe reticulation, like a crinoline glued to it.

The queen of the boletes with reticulate stems has to 
be Frostiella russellii/Boletellus russellii 
with her deeply carved reticulation.

A friend said its stem looked like a Cadbury Flake bar.
I knew there was something in my past that made me salivate
the first time I found a Russell's Bolete!

But what I like most are mushroom caps that have wrinkles or reticulation – like the cap of Boletus callisteus's brother, B. reticulatus, which is named for this phenomenon. 

Bolbitius reticulatus often has a pretty violet tones.

The cap of B. reticulatus is covered with a viscous coating that 
makes it hard to photograph its wrinkles. See Mycoquebec 
for much better images and full description.

Like B. callisteus, B. reticulatus becomes strongly 
translucent striate as it opens. 

Sometimes there are no violet tones at all.

Cap wrinkles are also common in many Pluteus species (pink-spored, free-grilled mushrooms that grow on wood). 

Pluteus granularis with guttation-droplet jewellery 

Pluteus chrysoplebius can be deeply wrinkled when young. 

Pluteus thomsonii – the prince of Pluteus reticulation

Here's a few more: 

Psathyrella delineata – The Wrinkled Cap Psathyrella

The Gypsy Mushroom – Cortinarius caperatus

And I'd be remiss not include the craziest reticulate cap of Rhodotus palmatus: 

Reason #4

Pure aesthetics. I think this mushroom is gorgeous. I can never resist taking out my camera. 

See Mushroom the Journal for definitions of various terms for forms of wrinkles on fungi.

Unless otherwise noted, all photographs © Jan Thornhill