The “Beard Lichen”, Mysteries, and Scientific Revolutions

Bryoria

A Beard Lichen, also known as Bryoria spp., at the Turnbull National Wildlife Refuge.

One of the most ubiquitous lichen around our parts is the lovely Beard Lichen. It’s also known as Bryoria which is the name of the fungus that is in the lichen symbiosis. You’ll see the greenish black beards hanging from the branches and tree trunks all around Mt. Spokane, over by Fishtrap Lake and Hog Canyon, and of course, at the Turnbull National Wildlife Refuge.

Identifying Bryoria

Getting down to Genus

A conifer covered in Alectoria sarmentosa and Bryoria spp. over on Mt. Spokane

Bryoria as a genus is pretty easy to identify. There are only a few look alike in our area: Pseudephebe pubescens, which grows on the north side of rocks while our Bryoria usually grows on trees; and then there’s the tiny, tufted, and stiff Nodobryoria abbreviata, which contrasts strongly with the usually pendant, pliable, and hairlike Bryoria. Up in the mountains you might run into Alectoria sarmentosa which is light green, while Bryoria are shades of brown and olive green, or Nodobryoria oregana which is a red beard like lichen. And that covers the look alikes around our region.

Getting down to species

Although distinguishing Bryoria from other look-a-likes takes less than a couple seconds usually without a hand lens, determining its identity at the species level is quite another ball game — oooh does it gets tricky! Why’s that?

K_red - norstictic acid in Bryoria

Norstictic acid: a K+red reaction in a Bryoria spp. as seen under light microscope at 1000x, I think. The Herbarium's scope is 1unit=10um as tested with micrometer - perfectly calibrated :)

Well, first off, lots of chemical tests are needed to differentiate between species, and since the branches of Bryoria are so tiny (often less than 1mm thick) you have to be careful not to use too much chemical or you risk diluting the reaction which can result in a false negative (thank goodness for dear friends like Jason Hollinger at Mushroom Observer who pointed out this concern to me). So to counter that issue I’ve resorted to using dissecting probes to apply K and KC (both using a 400x light microscope to look for norstictic acid crystal), C, and PPD. Using dissecting probes to apply chemical tests to Bryoria is a deep practice in patience: those tiny sections of Bryoria firmly stick to the probe by hydrogen bonds and attempting to get them released sometimes causes them to fly to indeterminable locations.

Secondly, finding the soredia for doing chemical tests can be difficult, basically because in some samples there are no soralia (the beds that contain soredia) to be found except just a couple empty soredia-less pits – which leaves one to guess about a) the color of the long-gone soredia, and b) whether the soredia could have tested positive or negative with the PPD test. But do remember, if you find empty soralia, be sure to jot down in your notes the shape of that there empty soralia, ideally with a drawing — it might be useful later on when you’re going through the keys. And yes, if you’re new to lichens, or mushrooms, you should be writing down all your observational notes before you go through a key to avoid any expectation bias.

Getting down and dirty at the EWU Herbarium

And thirdly, it can sometimes be difficult to differentiate between true pseudocyphellae and scars on the branches. Due to their pendant nature, Bryorias seem to crack and then heal alot, leaving scars that look like pseudocyphellae (or perhaps those really are pseudocyphellae?!).

Oh, and fourthly, one must be very very careful to comb through a sample because different species are often tangled together like lovers from different tribes.

Bryoria at the Refuge

The current list for the Turnbull National Wildlife Refuge lists only one species of Bryoria: B. fremontii also known as “Wila”, or “Edible Horsehair”, a starchy and abundant lichen that has been eaten by Native folks in our region for thousands of years.

The rare yellow apothecia on a Bryoria fremontii

Chemically, B. fremontii is a species that tests negative on all standard chemical tests (K, KC, C, and PPD). So you can imagine my excitement when I was getting down and dirty with six samples of Bryoria that I collected at the refuge and three different chemical types popped out – that means two new species get to be added to the list! If my identification are verified to be correct, the new additions include B. fuscescens and B. pseudofuscescens.  [Authors note: since writing this, there is a possibility that some of the B. fuscescens may actually be B. lanestris despite the obvious range inconsistencies, more on that slim possibility later]

Beyond adding species to lists, what got even more exciting is when I started growing through (yes, “growing through”, learning is a growing process) more samples of Bryoria from the refuge and found one sample that had yellow lecanorine apothecial discs, which is rare to find! And *and* in another sample I found yellow soredia, finally!

yellow soredia on a Bryoria fremontii - the soralia on this species are small and unusual.

Yes, simple things do excite me greatly – especially because those features helped to confirm that in both cases I’m dealing with B. fremontii despite the two samples seeming to have distinctly different morphologies. Earlier I was thinking that there was a “good chance” that both types were B. fremontii, but I just wasn’t sure — until I found those yellow soredia and apothecia, they brought my confidence level up to nearly 100% because B. fremontii is the only species in the genus with yellow soredia. This revelation helped me to see and feel with my fingers the major differences between what were two previously distinct species: B. tortuosa and B. fremontii – Edible Horsehair and Inedible Horsehair, respectively. Despite their major differences in color, texture, and size of main branches, they are now known to actually be the same species: Bryoria fremontii. If you non-lichen-nerds feel like you are spinning right now, and you’ve valiantly already made it this far into this blogpost, hold on cause it gets alot clearer (I hope!).

The Mystery of Edible and Inedible Horsehair

Map of Edible and Inedible Horsehair and First Nations Peoples; Courtesy of Millifolium, Wikipedia.

A few years ago a grad student out in Norway got a really neat idea: to test the genetics of Edible and Inedible Horsehair to see if they are the same species. And her results showed that indeed, they are the same fungal species and probably the same algal species too — except that this species has two different chemo-types: one has a high level of the toxic compound called vulpinic acid, whereas the other has a nearly absent level yeilding its use as a food for thousands of years. The presence of a high or nearly absent level of vulpinic acid results in two different morphotypes that are distinctly different by color, touch and taste. Lots of folks are probably saying, well yeah, sure, they’re two variants, but no, they are not — they are not known to intergrade, i.e. there aren’t hybrids between the two morphotypes. The lichens in question are two seemingly distinct species that have the same genetics. How can this be? How and why does such a phenomenon occur?

Enter Trevor Goward, one of my favorite lichenologists (along with Bruce Ryan!). In Goward’s  essay “Reassembly”, (the sixth essay in his series in the journal Evansia, “12 Essays on the Lichen Thallus“) he discusses this mystery at great depth… and the ideas presented are nothing short of fascinating and provocative, and as always, relating the lichen thallus to an aspect of human life:

…it helps to recall that lichens, though they look and behave like organisms, nevertheless operate as systems (Essay V). This means, for example, that it’s not quite right to say that lichens “grow.” As a matter of fact, plants and animals and fungal hyphae all grow; but lichen thalli “elaborate.” Lichens are more like a good conversation, each following its own internal logic, no two thalli coming out quite the same… ( p. 4)

Isn’t that just an awesome way of looking at lichen? Poetic, just beautiful. But, back to the topic at hand – the mystery of the Edible and Inedible Horsehair, and why they seem to act like distinctly different species.

Goward presents the “Thallus Reassembly Hypothesis” to explain the mystery, and this hypothesis also presents a more concise way of understanding how variants and subspecies might occur. But to sum the hypothesis up in a few sentences would be doing the concept injustice, so I erased those feeble attempts, instead I’ll just point you to his essay directly.

However, I will comment that it’s application can extend far beyond lichens, and even go so far as to help contemplate some recent groundbreaking genetic research.

Goward's Thallus reassembly hypothesis

Just a couple weeks ago, ecologists from University of Illinois presented findings demonstrating that the tissue from the leaves and roots of a black cottonwood tree have entirely different genome sequences even though they are part of the same individual (the entire genome was sequenced from these different tissue sections). But, and here’s the clincher, the leaves from different clones of black cottonwood were shown to have nearly the same genome sequence. The pattern is kinda like lichens turned on their head, as well as touches upon how the different environmental conditions (underground vs. above ground) yield significant changes in genome sequences within the same individual – not just within the same species! Sounds like our Edible and Inedible Horsehair mystery, doesn’t it?

To quote Brian Olds, one of the researchers, “This could change the classic paradigm that evolution only happens in a population rather than at an individual level.”

Scientific Revolutions

In the face of this cottonwood gene research, the entire field of epigenetics, and Goward’s contemplations on the lichen thallus, it seems as though the natural sciences are on the cusp of a radical scientific revolution. A paradigm shift where the rigidity of our understandings of genetics and evolution, and perhaps ecology too, are beginning to crumble as the fluid and dynamic nature of these systems becomes more and more evident. This would be akin to astronomers finally realizing that the earth is not the center of the universe even though the equations for the movement of the stars and planets moving around the earth had almost fit the observations perfectly, albeit with some bizarre mathematical contortions and many unanswered questions…

But maybe I’m going too far, and I see all this because I am still a young student in the natural sciences and have so much yet to learn. Or maybe, just maybe, a metaphorical veil really is being lifted and biological paradigms shifted — and here we stand right in the middle of a most fascinating era of reveries. Either way, it’s all exciting, that is for sure!

– Nastassja Noell

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