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- [Woman] Take these cards.

- Yeah.

- Welcome to After Dark Online. Thanks for joining us again as we continue to explore the world through science, art, and conversation. My name is Sam and I'm a program developer as part of the team that produces After Dark Online. And though this program is virtual, the Exploratorium is located on Pier 15 in San Francisco, on unseated territory of the Ramaytush Ohlone. We recognize that we are guests on this land and we honor the conservation and stewardship the Ohlone have offered the ecology we inhabit, both past, present, and continuing into the future. Tonight on After Dark Online, we're celebrating fungi. Fungi is an expansive kingdom, which includes molds, yeast, and also most recognizable, mushrooms, which is what we'll be focusing on tonight. We'll hear from a taxonomist describing spores, their shape, and propagation, as well as a local photographer who makes gorgeous portraits of mushrooms and slime molds, that can be found in local parks. In between, we'll share a short film based on a poem by Neil Gaiman, called "The Mushroom Hunters". It's a beautiful animation that frames mushroom hunting as a metaphor for knowledge building, practiced by humans through observation and experimentation. But first, we'll turn to a conversation with photographer Alison Pollack and my colleague, Emma Greenbaum, where she'll share a slideshow of some of her other worldly photographs of mushrooms and slime molds. Alison Pollack is a macro photographer, who specializes in photographing fungi and myxomycetes barely visible to the naked eye. Searching out her subjects on the forest floor, magnifying glass in hand, she uses advanced photography techniques to reveal the surprising detail of these organisms, most just a few millimeters tall. Her goal is to reveal this tiny and colorful world in a format that is as much art as it is science. Allison's photographs have been featured in national and international magazines, and she has also displayed her work in exhibits in the Bay Area. You can find her on Instagram with the handle, marin mushrooms. My colleague, Emma Greenbaum, is a program manager for the Exploratorium environment initiative, focused on climate adaptation and resilience. She's a spatial data analyst, environmental planner and organizer, and holds a master of environmental management from the Yale School of Forestry and Environmental Studies. We're grateful to Alison for sharing some of her work and be sure to check out the more to explore page on our listing in the show notes for her social media links and recommendations for mushroom hunting magnifying glasses. Enjoy.

- Welcome, Alison. It's such a pleasure to be speaking with you again. Thank you for being here and we're gonna have the great pleasure of seeing some of your photographs this evening. So can you tell us a little bit about who you are, and what you do, and what you'll be showing us?

- Hey, Emma, thank you. I'm delighted to be here. I am a photographer and I get very excited about little, little really tiny mushrooms and really tiny things that grow in the forest. And my goal in my photography is to make these tiny things really big so you can see them, and to show their beauty, and I hope to get people to want to go into the forest to look for these things themselves.

- Fabulous, so I work on climate adaptation and climate change in the Bay Observatory at the Exploratorium, and we really think a lot about observation and we think a lot about scale. We have these sort of global problems, but also manifest in these local ways and often in these very tiny ways. So can you tell us a little bit about scale and about your process of how you take these photographs, and also what we're looking at here?

- Well, just a little bit about scale, most of the things that I photograph are a few millimeters tall, I mean, you know, very, very small, and you can't see them as you're just walking through the forest. So I look for things in the forest, I stop, and I sit, and I look around for things in the forest. Now, this one right here is a fungus called Xylaria hypoxylon. And I was actually walking up a favorite trail to a log that I like, and this, I saw actually at eye level, it was growing on a decomposing log that was pretty high. And what I saw was those droplets, and when I went closer, I saw that the entire forest was reflected in the droplets. And so while these are a little bit bigger than I normally photograph, maybe this big, I just thought that it's like the world in a droplet. Yeah, I like this photograph.

- Yeah, this is incredible. You really can see sort of everything reflected back at you in these little dew-like drops on these kinds of interesting sculptural, I think, fungus, this is the fungus?

- Yes, it's a fungus, Xylaria hypoxylon.

- And so today we're gonna be looking at both fungus and a different kind of organism that you'll tell us about.

- Yes, myxomycetes, otherwise known as myxos, but we'll talk about them a little bit later. We'll start first with a bunch of photographs of fungi.

- Excellent.

- This little beauty is called Lachnum virgineum. This, again, is very tiny, so, you know, within a pinch of my fingers here. And I love this one because it's almost always has, when they're fresh, it almost has always has these beautiful, beautiful droplets. And if you shift to the next photo, you'll see that these droplets, oftentimes, are on the sides as well as the tops of the mushroom.

- [Emma] Wow!

- [Alison] I went out into the woods a few days ago and I found some of these, and I brought a piece of wood to show you for scale what I'm actually looking for.

- Great.

- So on this piece of wood, I'm gonna hold it up, where my finger is, there's a little cluster, you probably can't see it clearly, but you can see just little white dots. And those little white dots are the same fungus that we're looking at on the screen here.

- Oh, wow, so incredibly tiny. How does one see these if you're in the forest? It seems like you'd really have to be attuned to what you're looking for.

- Yes, you really do have to be attuned. At the beginning, it took me a long time but now my eyes are pre-attuned as you say. So I don't walk fast at all, I walk extremely slowly and sometimes I just sit. If I'm in a nicely wet forest and I just sit where there's any decomposing wood and look around within a two foot radius, I'm guaranteed to find something small. But basically, I'm looking for dots of color like those dots on that piece of wood. And then I get closer and I pull out my favorite tool in my camera bag, which is an led-lit magnifying glass. You can get these on Amazon for about 10 bucks and we'll have a link on the website. And so this is a 10X, it multiplies by 10, what I'm seeing. So this really helps me to see the little tiny guys. So I look for dots of color and then I look with this, and sometimes I'm folded and it's just ordinary mold I see, and sometimes it's something really beautiful. Many times it's something really beautiful and then I get excited. This one always excites me. This is fairly common in the local woods, it's called Chlorociboria. It's blue, this color blue. It can be a bit blue-green. These guys are, again, about this small, so we're talking very, very small. If they're out there, you can see them, there are very bright blue. So you don't need a magnifying glass to see these. And these will stay in the woods. So if they've been there before, you might see blue-stained wood. In fact, that blue-stained wood was used in the Renaissance to make wooden furniture with colors. It's a gorgeous, a gorgeous, gorgeous, gorgeous fungus.

- Wow, so again, very... I mean, these ones seem like they might be a little bit easier to see but still so tiny. How did you first notice them?

- Well, these you can see with your naked eye. So even as you're actually walking through the forest, if you're looking at logs, you can find these. So most things I look at are on either decomposing logs or leaf litters. So decomposing logs might be on the ground but sometimes they're pretty big, and sometimes there are decomposing logs at eye level too. So when I'm walking through the forest, I am usually looking for nicely decomposed logs or piles of wet leaf litter, and I might poke around in the piles. Most of the things that I photograph either grow tiny mushrooms that are growing on the ground or they're growing on the tops and sides of decomposing wood. But I have to look really, really closely. And a lot of times, I will take this, especially if the wood is dark, 'cause a lot of the things that I photograph are dark and they blend into the wood, so I'll take my magnifying glass with the light and I'll turn the light on, and I will scan the log, looking for tiny things. Because a lot of times I won't see it without the light but the light will capture things. This one I actually photographed when I was hiking. This is many, many years ago. I photographed it when I was hiking, not realizing how unusual it was. It's a shelf fungus, a polypore or a bracket fungus, and these blue drops are something called guttation. And guttation is not that uncommon in mushrooms, it's like the mushroom is sweating, and it tends to occur when mushrooms are growing rapidly. It's a product of how they're growing and what they're eating. But I've never seen it in blue since then. It's like glass sculptures there. It's not a great shot photographically, but that blue color is just so gorgeous. This one I found in Redwood Regional Park in Oakland, and it is called Hygrocybe flavifolia. Hygrocybe is a class of mushrooms called waxy caps. And you can see why the caps are... They tend to be shiny, sometimes a little bit viscid. And this one I saw and at first, I saw it from the backside and all I saw was one mushroom. And I used my phone to look underneath the other side to see what the gills were, and I saw that there were two more mushrooms. So I spent about an hour cleaning this mushroom before I photographed it, because the top is slimy so it attracts all kinds of dirt. I carry tweezers and mini paint brushes with me. So I spend a lot of time preparing my specimens and cleaning the background so I can get as pretty a shot as possible. And then it turned out, when I posted this, somebody said, "Do you realize what you have here?" So it turns out that this is an extremely rare fungus. It's on the endangered list, and only a handful of recordings have been made of this fungus. This one is a really fun one, kids love this one. It's common name is ear-pick fungus, and it grows on pine cones. In our area, it's mostly growing on Doug-fir cones, but the cones are small and the fungus is, again, pretty small. So the fungus itself is maybe about this big. And we have two views here, the left side is a side view. The top is crinkly and hairy. And then I just angled the cone a little bit so I could get a photograph of what they call teeth. It's a tooth fungus. These things are so, so, so beautiful. So if you see pine cones, look carefully at them because they might have tiny fungi on them. This is a eucalyptus seed pod. So eucalyptus seed pods are about this big. And my friend, Debbie, found these in Tilden Regional Park. And she took some home and kept them moist, and they started growing these little, tiny orange cups. In the mushroom kingdom, those are phylum called Ascomycota, which are cup fungi, and most of the fungi I photograph are these tiny Ascomycota. And these are are called Rustroemia, something like that. And it's amazing to me that you'll have dozens of these growing on a little little tiny eucalyptus seed pod.

- So you can actually take, if you find something in the forest, you can take it home and grow it at home?

- Yes. So the things I take home from the forest tend to be the size of a dime or less. Well, that Lachnum them on the wood, I took that home mostly because I wanted to show it in this video, but I also take things home to photograph them. So things like this small, for example, I can photograph it with an ordinary lens, but to do it really justice, I have special, extreme macro lenses that I use. So I will take things from the forest, and you can put them in a small container, like a food container, just a simple food container like this, and put a paper towel at the bottom and put wood in there. And as long as you keep it moist, just keep it damp, mushrooms will continue to grow. And sometimes you find new ones. So sometimes I take home a piece of wood from the forest because I wanna photograph something on it, and I'll put it in, this is called a moist chamber, and some number of days later, I'll have a different fungus on there. This is another waxy cap. I put this one in, it's actually rather large for what I photograph. This one tends to be about this big, so it's pretty big, but they are in glorious colors, bright red, bright orange, bright yellow. Typically in January, I see them a lot in Redwood forest, normally in January, not sure about this year. But they're brightly colored and really pretty. This is a Marasmeillus, I believe, mushroom. And I took this picture because I love the delicate, lacy, almost translucent gills. They're just really, really, really pretty to me. This mushroom is maybe about this big. They tend to grow in clusters. This is from the Redwood State Park, and I found an area where I found dozens of them. But this one was by itself and it just... I don't know, I was just mesmerized by these gills. This one is, the common name here is eyelash cup fungus and you can see why it's called eyelash cup fungus.

- [Emma] Yeah.

- They're fairly small, but you can see them with the naked eye. You know, each one of these is maybe this big, about my usual size. They're fairly small. They can grow in clusters, so you can see them. They tend to be bright orange, sometimes they're red. They're really, really, really pretty. This is another one where I spent probably a half an hour cleaning out the insides of the mushroom so I could portray it in its most beautiful way.

- I really love how, since you're looking at decomposed wood and wet leaves, it's always sort of this rich black background with these beautiful colors or these kind of crisp whites. Really beautiful.

- Thank you. Okay, we're actually leaving the United States now, and I put in a few photos from journeys to other countries. This was taken in the Manu, it's a national preserve in the Amazon in Peru. And I think these are Marasmeillus, but I'm not sure, but I actually call them Bundt pan mushrooms because they look just like Bundt pans. For those who don't know them, those are a type of cake pan. But they completely look like tiny Bundt pans to me. This mushroom is a Mycena, and this one I found in the Highlands in Colombia last year. And what struck me about this mushroom and really drew me to it, is the gills are something called marginate, the color at the bottom of the gills is a darker orange than the rest of the gills, and I just think that is incredibly beautiful. Mycena are very, very common, but this one I don't think we have here in California. But we do have Mycena in California that do have gills with different colors on the bottom.

- So you are capturing this very fine detail on these already incredibly tiny things, what is your process for capturing these photos?

- So that's a good question. A lot of people think that when they see my photos, I just set up my camera and I snap a shot. Well, it's a lot more complicated than that. I use a process called focus stacking. So when you take a photograph of things as tiny as I photograph, the depth of field is really, really thin. And by depth of field, I'm referring to the portion of the image that's in focus. So if I shot just one picture of this mushroom, you might only see a tiny bit of the stem in focus or a tiny bit of the cap. So in focus stacking, what happens is I take a series of photos from the front to the back of my mushroom, or myxo, or whatever it is I'm photographing, and I move the camera a tiny, tiny, tiny bit for each shot. And so for this one, I might have had maybe 30 or 40 shots. For some of my other things that are even smaller, I may have hundreds of shots. So the higher the magnification, the smaller the depth of field. So I have all of these images that are stacked, is the terminology, and then there's specialized software that combines all of the in-focus parts of each image into a single composite image. It's magical. The first time I did that and the composite image showed up on my screen, I just about jumped out of my chair. It's just amazing. So the next photo is also from the jungle of Peru. Sorry, it's from Colombia. This one is called Cookeina, and this was in a hot and steamy jungle in Columbia. And I thought it was really beautiful. It's common there, but when I knelt down to get my camera gear and I looked underneath the mushroom, I saw that little bit of light there, and it was the light shining through some of the trees in the jungle, just lighting the base of the mushroom. And I quickly got my camera gear ready to take a stack of photos, and I managed to do that and still keep that light in there. It was all the more challenging here because in that jungle, there were a lot of army ants, which can be very nasty and they were swarming all over, and I'm desperately trying not to have them climb on top of me while I'm taking this photograph. And now we are in the world of myxomycetes. Myxomycetes, the term comes from Greek from myxa, which means slime because when they're young, they have this sort of a slimy substance called the Plasmodium, I'll show a picture of that later, and that turns into fruiting bodies, which is what we're seeing here, that come in different shapes, colors. They're amazingly beautiful when you look at them at a tiny scale. This was the very first one I found, I discovered, quote, unquote. I was walking at Lake Lagunitas, and I saw, on the stump of a redwood tree, a bit of a branch that had these yellow things on it. And I looked at it and I had no idea what they were. This is relatively big. What you're seeing here is about this big. So I took a picture of it. I didn't take it home, but I took a picture of it. And I came home and I did a Google reverse image search, and I figured out what they were. And I started doing that at about four in the afternoon, and I kept reading and reading because I was fascinated, what I was seeing and learning about these. And I didn't turn the computer off until four in the morning. I was completely smitten. And ever since then, I have been a slime mold and tiny fungi photographer. This one is a myxo, Badhamia utricularis, which are those orange beans, they're dangling from a mushroom. So the myxo actually-

- [Emma] So kind of bridging worlds here.

- Yes, the myxo feeds on the mushroom, it's a Stereum mushroom, it's fairly common, and we're bridging worlds. And to get a sense of scale, we'll look at the next photo, it's the same slime mold, but-

- Oh, wow!

- [Alison] But a huge cluster, actually, it was gorgeous, on a long log in Baltimore Canyon. And those are my fingers. I'm small, so my fingers are pretty small. So you get a sense of scale there. And as well-

- This one really, you could really see this.

- Yes, you can see because it's a huge fruit, I mean, it's easily this big. So this particular myxo can be in very large fruitings. And when you see them, they're gorgeous. This one's amazing. Like one of the things that fascinates me about myxos, and this is a great example, is they change color. Their life cycle is fairly short, it's maybe two days to a couple of weeks, and in that time, they change color, shape, form, texture. This particular one starts as a yellow slime, Plasmodium, and then these fruiting bodies form. And they start yellow like this and then they turn sort of a buff color, then they turn a dark slate gray, and then a gorgeous steel blue, sometimes purple, and sometimes iridescence. They're amazing.

- Oh, wow!

- Absolutely, one of my favorites. So the previous one, we had a slime mold eating a fungus and now we have a fungus on a slime mold. So the little yellow lollipops there are a fungus called Polycephalomyces tomentosus and it commonly feeds on old slime mold, which is what we're seeing here. It's an old Trichia. Now, you can't see this with the naked eye, in my trained eyes, I might see what looks like it might be slime molds but there's a lot of white fuzz on it. And even with my magnifying glass, it's really hard to see that that white fuzz is this. So these are the kind I will take home a tiny bit of the wood and take it home to photograph with stronger macro lenses that I have at home. So here is Plasmodium. This is what gives slime molds the common name, slime mold. So that yellow, oozy substance is a little slimy to the touch, it's called the Plasmodium. And that's the initial, once the the spores get together and they merge, they create this Plasmodium, which grows, and moves, and creeps or oozes along the wood. And in this case here, we actually see these gray disks are a tiny fungus called Mollisia, very, very, very common in our woodlands but you have to use a magnifying glass to see them. They eat mushrooms, they eat bacteria, they eat all kinds of microscopic things. And at some point when the food becomes scarce, the Plasmodium disappears and all that mergers upwards to create these fruiting bodies. The Plasmodium disappears and the fruiting bodies appear. You see the fruiting bodies more often than you see the Plasmodium because the Plasmodium might be inside the wood or underneath the leaf litter. This is one of my favorites and my husband's absolute favorite mushroom... Slime mold, sorry. It's called Comatricha nigra. And as almost all slime molds do, it goes through color changes. It starts white, and then turns this beautiful pink, and then mostly maroon, dark maroon, and almost black. The pink stage doesn't last for a very long at all. So I was really delighted to be able to capture this one in the pink stage. I think they look like ballet dancers. I often anthropomorphize what I photograph. And to me, I see these ballet dancers gently swaying with each other.

- I would imagine these take a lot of patients to capture and would give you a lot of time for your imagination to kind of play out scenes in these teeny-tiny worlds.

- Yeah, I should say, in the focus stacking, so this one I would call sort of a mid range for me, mid range magnification. And so this photograph, to compose it to do all the stacking to create the photograph, probably took me about three hours. Some of the others take an hour, sometimes it might take me five hours. I have four different kinds of macro lenses, two I use in the woods and two I use at home, and for photographing at this level of magnification, I can't turn my focus ring in small enough steps with just my fingers, so I actually have an automated rail that moves my camera in microns, which a micron is a 1,000th of a millimeter. It moves the camera in numbers of microns of steps, very, very, very tiny steps. This is one of my personal favorites. I love the color, I love the combination of the green and the orange, and I especially love the stalks on here, they look like glass sculptures. Absolute beauties. You can see these with the naked eye in the forest when they're this color, they're very, very bright. They can be orange, almost red, peach yellow. It's called Trichia decipiens. To me, this is like a work of art. This one is called Cribraria cancellata, very, very difficult to find in the forest because it's almost always on dark decomposing wood, and so it's really hard to see. And so to find these, let's pretend this is a piece of wood, I might pick up the wood, and I have to roll the wood, and then look at it with my light, because I'll catch it on the edge. If you look straight on, you're not likely to see it. So I've learned to roll the wood and look with my light. Most slime molds are pretty hard to identify to species with a photograph, but this one you can. You need microscopy to determine, but this one you can. It's the only one of its genus that has these wire, what I call cages, and the spores are inside that wire cage. You can still see some spores in there. So as the myxos mature, they have this outer shell called the peridium which holds up the spores. The outer shell dries out and reveals the spores within, and then the wind disperses the spores. This one is the first photograph that I did of a single slime mold. I probably spent 40 hours getting this photograph together. And what absolutely astonished me when I did this was the level of detail that can be seen. This is one millimeter tall, so you almost have to squish your fingers together. I was amazed to see this crystal-like structure on the top, which is called the sporocarp, those were actually lime crystals. This species is the Didymium squamulosum, tricky for me to pronounce. It's amazing to me the level of detail on these tiny, tiny, tiny, tiny things. This is another favorite. Also very common, probably the most common myxo in our local woods. You can see it because it grows in big clusters like this. This piece of wood is probably about this big, and sometimes it can be along an entire log. It's really amazing. The common name is coral slime mold because it does indeed look like sea coral. And so in the next four, what we're gonna see is two of these little fingers here. So that's two of the fingers of that coral slime off on the previous photo. We're talking about very, very, very tiny here. This is probably a quarter of a millimeter tall. And I photographed this with a microscope lens mounted to my camera. So that gives me, with such magnification, it's a 10X microscope lens adapted to my camera, and it has really tiny depth of field. So this photo is a focused stack of about 300 individual images, but here you can quite easily, excuse me, quite easily see the single spores hanging on threads on the outside of the structure. And again, the stem here, it looks glass like to me. This is one of my favorites. This is from Alaska last summer. I believe this is the Didymium squamulosum again but I'm not for sure, I would have to do microscopy, but I just love the image of them playing and marching. It kind of looks a little bit to me like lemmings going to the edge of this, you know, going to the sea. I just think it's really pretty. This is another one I did with a microscope lens. It's called Arcyria pomiformis. It's actually apparently not one that grows very well on the woods, but I grew this one at home in moist chamber. So I showed that to you before, but I'll show you again, it's this little box. If you take pieces of decomposing wood, small pieces of decomposing wood like what I have here, and soak them in water for 24 hours, pour the water out and then put a paper towel at the bottom of a container, and keep that paper towel damp, not wet, but damp, and the container mostly closed, slightly ajar, you can grow things at home. So slime molds or myxos will grow, and tiny fungi will grow. So this was one that I was delighted to grow at home. And I watched it mature. On my website, I actually have this in several different stages of its growth. It, again, changed colors several times. So when it matured and dried out it had spores inside and I very, very gently blew out the spores to reveal the threads that hold the spores together, they're called capillitial threads. Because they look to me... I don't know, they're just beautiful. They look like the filaments of a light bulb. This is another one where I think it's nature is art. These are a genus called Lamproderma. Most of the Lamproderma species are iridescent and I love the iridescence. I didn't actually grow these nor did I find them, but somebody sent me a question on Instagram and asked me what they were, and I said, "They're Lamproderma, "can you send them to me?" And he was a biologist, so he did, he sent them to me in a test tube. And another thing I should say about myxos, mushrooms will shrivel and wrinkle when they dry out, but myxos will retain their shape when they dry. So these things that I photographed probably six months ago, still look exactly like this today, but they're absolutely gorgeous. I think this is the last one. This is Physarum album which I also grew in a moist chamber at home. And again, they go through color changes. The fruiting body starts white, and then it turns pink, and then it turns a beautiful blue. And the pink doesn't last very long, especially when they're not in their natural environment, it doesn't last very long at all. These were pink for less than an hour. So I knew that they were going to change fast, so I kept watching. And when they turned pink, I just was like a mad woman, getting everything set up to photograph them. And I didn't even know if they would stay pink during the time it took me to photograph them. This is a photo stack of about 250 images.

- Alison, thank you so much. You know, I've had a chance to look at a lot of your photographs, and hearing you describe each one is just so wonderful. When you describe kind of the damp forest, I can kind of feel that coolness as I'm looking at these different myxos, which I love myxos instead of slime molds, 'cause I think that does sort of bring a reaction. But these worlds are so incredibly beautiful, and I'm wondering, you know, you do a lot of observing and a lot of appreciating of the beauty that's in the woods, and I'm wondering how you connect that to these bigger concepts about forests or what you hope to bring to people through your photographs.

- Thank you. And I wanna say again, thank you very much for having me, it's been a pure delight. I love sharing these tiny worlds with people. I love opening people's eyes to the magic of nature, and on Instagram, my very favorite comment is when somebody says, "Wow, "I never knew these things existed. "I'm going to go look for them." So my goal is in fact to get people to go look for them and to appreciate being out in the woods, especially in this time when we have so many restrictions, you can go out into the woods by yourself. The smell of the wet woods is wonderful. Take a magnifying glass, take a look, look really closely. It's very calming, relaxing. I want people to appreciate the woods. We need decomposing forest. We need old growth forest. We need forest to keep renewing our souls and renewing the planet. So I want people to look at them and to get them invigorated to keep defending the forest.

- Well, I feel incredibly inspired to go find these things, and I'm gonna run out and get my very own LED magnifying glass. So thank you so much. And you'll be sharing some of those links with us, if folks wanna take this up and go find things in the forest.

- Thanks very much.

- [Narrator] "The Mushroom Hunters by Neil Gaiman. Science, as you know my little one, is the study of the nature and behavior of the universe. It's based on observation, on experiment, and measurement, and the formulation of laws to describe the facts revealed. In the old times, they say, the men who came already fitted with brains designed to follow flesh beasts that are run, to hurdle blindly into the unknown, and then to find their way back home when lost with a slain antelope to carry between them, or on bad hunting days, nothing. The women, who did not need to run down prey, had brains that spotted landmarks and made paths between them, left at the thorn bush and across the scree, and looked down into the bole of the half fallen tree, because sometimes there are mushrooms. Before the flint club or flint butchers tools, the first tool of all was a sling for the baby to keep our hands free and something to put the berries and the mushrooms in, the roots, and the good leaves, the seeds, and the crawlers, then a flint pestle to smash, to crush, to grind, or break. And sometimes men chased the beasts into the deep woods, and never came back. Some mushrooms will kill you, while some will show you gods, and some will feed the hunger in our bellies. Identify. Others will kill us if we eat them raw and kill us again if we cook them once, but if we boil them up in spring water and pour the water away, and then boil them once more and pour the water away, only then can we eat them safely. Observe. Observe childbirth, measure the swell of bellies and the shape of breasts, and through experience, discover how to bring babies safely into the world. Observe everything. And the mushroom hunters walk the ways they walk and watch the world, and see what they observe. And some of them would thrive and lick their lips, while others clutched their stomachs and expired. So laws are made and handed down on what is safe. Formulate. The tools we make to build our lives, or clothes, or food, or path home, all of these things we base on observation, on experiment, on measurement, on truth. And science, you remember, is the study of the nature and behavior of the universe, based on observation, experiment, and measurement, and the formulation of laws to describe these facts. The race continues. An early scientist drew beasts upon the walls of caves to show her children, now all fat on mushrooms and on berries, what would be safe to hunt. The men go running on after beasts, the scientists walk more slowly over to the brow of the hill, and down to the water's edge, and past the place where the red clay runs. They're carrying their babies in the slings they made, freeing their hands to pick the mushrooms.

- Thank you to the producers of "The Mushroom Hunters", for allowing us to share that film with you. Now, we'll turn to a scientific lens on mushrooms, specifically spores, with Dr. Else Vellinga. She'll share a wonderful presentation called fascinating mushroom spores, in which she details the size, shape, and behavior of mushroom spore propagation and how it contributes to the survival of the species. Dr. Else Vellinga is a mycologist who is interested in naming and classifying mushroom species in California and beyond, especially parasol mushrooms. She has described 22 species as new for California and most recently worked at the herbarium at UC Berkeley and San Francisco State University, for the macro fungi and microfungi collections digitization projects. She got her training at the National Herbarium in the Netherlands, and her PhD at the University of Leiden. In 2019, NAMA presented her with the Gary Lincoff Award for her contributions to amateur mycology. Else is also an avid knitter and likes to use mushroom-dyed yarn for her creations. Enjoy Else's presentation.

- Thank you, Sam, and I'm really excited to talk about mushroom spores tonight. And I'll start right here with what mushroom spores are and what I do. So mushrooms are basically spore factories. They produce around 16 billion spores. Each of these honey mushrooms here produce gigantic amount of spores. And you can see the spores as this white powder. So spore is basically, comparable to us, plant seed. Every spore is half of a new individual. You need two to make a new individual mushroom producing organism, and individual spores are so small that you cannot see them with the naked eye. You can only see them in these big masses yourself, but not individual, you need a microscope. You have to put 10 or 12 side by side to have the width of a hair. A spore has to germinate. It puts out this tube, which we call a hypha, on a substrate where it is in the right spot, under the right circumstances. And again, this hypha, we cannot see with the naked eye, it's too small. It's much too small, it's even smaller than the spores we just saw. And then it branches out and forms this network, which we call a mycelium. This is still formed by one spore, but we need a second spore to have that genetic material together with the first one, and then we can have a mycelium that will be able to form a new fruitbody, when the circumstances are right. And those circumstances are about the right amount of moisture, the right amount of nutrients, sugars, and nitrogen, and also the right temperatures, not when it is freezing or bloody hot. So spores of a mushroom, they are formed at the tip of specific cells on the sides of the gills, and these cells have four prongs and every prong has one spore on top of it. And these are shot off and that mechanism which makes them shoot off is unique for mushroom species. It's not in any other group of organisms. It's truly unique. And here are time lapse pictures of mycelia. And you see here the spore and that is on top of the prong. And then it looks like it's blowing a chewing gum bubble, but basically it's droplet. So droplet is sugars which grows with time. And at some point, if it touches the part of the spore over here, which is hydrophilic, the liquid will flow over the surface of the spore and that will give it its momentum to be shot off. And that's shown in this little video here, where we have the basidium with the four prongs on the left, and here we have four spores, and this spore has the droplet growing. And then at seven seconds, you'll see suddenly that it flies off. There it goes. It gets this push just like a balloon gets a push. So it's a short distance, it gets shot off, and then it stops and it drops down in between the gills. And they're shot off something like around a millimeter. Some small spore are shot off a very short distance. The bigger spores are shot up farther, 'cause they're bigger, they have a bigger droplet, so they get farther away. And in this mushroom, where you have these white gills that are far apart, you might think the spores might be long. And yes, you're totally correct about it. The spores are twice as long as the average spore. They look like this, they look like upside down penguins, and they're shot off in this white space, and then they drop down, and then it gets into the air current. And there are really nice YouTube videos about it, so check it out. So it gets into the air, to the places, and then they'll land there. But not all mushrooms get their spores out by shooting them off. So these truffles, they depend on mammals for their spore dispersal. The mammal, the squirrel in this case, eats the little mushroom and then poops out the spores. Here are some spores. And so this doesn't get into the air at all. Puffballs, on the other hand, their spores do get off in air, but they don't shoot off them actively either, they just drop off the basidia inside its fruiting body, and then they need some help to get out of that mushroom, in this case, it's a hand, but in nature, of course, is just a stick or a deer that steps on them, and then there's this cloud of hydrophobic round spores that gets off, and that's where if there's wind, they bring them. And then the third different way of doing it is this way, by having your fruitbody and your spores, everything is tailored to dispersal by flies. It's pink mushroom, it smells of carrion, and it looks like carrion, and the spores are in this goo here. And the flies come and gobble it up, get it on their bodies, fly off, disperse the spores, and at the end of the day, you have this naked fruitbody, all the spores are gone. So we might think about whether there are other ways the spores are adapted to the environment and how do they get to the place they want to be? Are they big? Are they really tailored to be in the air and being exposed to UV light, for instance? So all these questions, we'll address now. So we have to start out with thinking about spores. Spores do come in many different sizes, shapes, and colors, but most, however, are just boring to look at. They all have the same kind of shape. Sizes, that's between seven and 10 micrometers long, they're colorless, and they're thin-walled. But there are also ones that are really exciting to look at, non-boring spores. Like on the left, these one with facets, they look a little like strange boxes. There's three dimensional weird things. On the right, there are these winged spores of Gauteria. So they're quite different than the white spores, boring spores we just saw. And then there are spores that are looking white but are a little bit more exciting because they have an ornamentation that is visible when you putting them in an iodine solution, so it reacts with that. It's a kind of a sugar component to the spore wall which turns blue in iodine, so it's visible under a microscope. And then when you put those spores under a scanning electron microscope, you can even see that ornamentation much better. So you can see ridges, and walls, and whatnot. Really fascinating. Function, we'll come to that a bit later. But so keep in mind, most spores are boring, no ornamentation, no colors, and thin-walled, but there are loads of exceptions. You can also ask about size, do small fruitbodies always have small spores and large fruitbodies, large spores? Having large spores is of course an advantage because you can give them more luggage for the way to the place they want to be. But it comes at a cost, you have to put all that luggage into the spore. And a small fruitbody probably doesn't have the resources to do so. So in this group of mushrooms, these are two closely related species, and yes, the smaller fruitbodies have small spores and these big fruitbodies have much bigger spores with a thick walled, and top they have a thin spot in the spore wall where they can germinate. And these spores are drawn by the same size. The same scale, that's what I should say. So in some groups, yes, definitely, large fruitbodies make larger spores than small ones. But it's nature so there are always exceptions to every trend we can come up with. And when we're talking about fruitbodies and those big spores, we also want to know, is there a correlation between fruitbody size and the way they get their nutrients, especially their sugars, their carbs? And for this, you have to be aware that there are different ways that mushroom species get their sugars. So the ectomycorrhizal species, they get their sugars from a tree, in exchange for nitrogen, water, and sometimes other minerals or metal ions. And this is a real quid pro quo. So the fungus brings water and especially nitrogen, and gets sugars back from the tree. And this is a relationship which is mutually beneficial but also obligatory, so they cannot live without each other. So these Boletus lives with the sitka spruce. And there's not only Boletus, there's porcini, but also chanterelles, and lots of Amanita species, and lots of many other species. They can only live in relationship with trees. And they definitely often make really large fruitbodies. This is a gigantic Boletus shown by a colleague of mine in Point Reyes. And then on the other hand, other side of the... We have those species that break down plant material, they decomposing, we call them saprotrophic. They live off dead material, and they break down dead material to get to their sugars. The ectomycorrhizal species have lost that ability. They cannot do that anymore. And it feels that indeed, many of them make only small fruitbodies. This is again on sitka spruce, needles, this little mushroom, very small fruitbodies. And you can see carpets of them on the forest floor. You can see carpets of all these small mushrooms, and you can mostly count on them that most of them, they are decomposing. Most saprotrophic species do have small fruitbodies. But of course, there are exceptions. And one of exceptions is this giant Macrocybe. But the big hat is what Macrocybe means, this is tropical species, this is a colleague, Matt Smith, who triumphantly shows this big mushroom in Florida. And this is really a big question on how is it possible that it can make these gigantic fruitbodies? How can they mobilize so many nutrients to make this? That's an open question. But in general, yes, ectomycrorrhizal fruitbodies are larger than those of saprotrophic fungi, but they're exceptions on both sides, which are the interesting ones, I think. But yeah, and they have also bigger spores the bigger the fruitbody, the bigger the spores. So the next question we want to ask is how far do spores get? Where do they land? And is there any correlation between spore shape and where they end up? As you can see here, most spores do not get that far because here all this white stuff is spores and they're on the fruitbodies, they're on the soil, and they don't stay long. You come a week later, you won't see them anymore. And they don't germinate all of them. But some spores can get really far away. Yeah, you have been doing that, you can go catch them 1,000 kilometers from where they started. But, you know, they're probably not very successful because you need two spores of different mating types of different gender, if you want to call it that, to make a new individual mushroom producing organism. So most, not that far. And of course it makes a difference whether you're a tall mushroom or one that's closest to the surface, makes a difference what kind of shrubs and other plants around it, or is it an open forest and they can move much further around. So it all depends on where they fruit. So the spores want to end up... Oh, want to, need to end up on the substrate they're tailored to. So in this case, this nice Mycena species, you know, really, California species, grows on oak leaves. It decomposes oak leaves. So it wants the spores need to end up on on oak leaves. But those of the ectomycorrhizal fungi, those that grow with trees, they can only germinate when they're close to a tree root, so they have to go somewhere else. They have to go into the soil. And you have people who have done that. They have this germinating pine seedling, it has mushroom spores put on there directly on the roots, and you can see that it was really very successful. You have here all this fungal mass, and here are the places where this is exchanged between the fungus and the three roots. The exchange of nutrients is in these little nodes. So this was very successful, but this was done by people. And in nature, there are no people around to put spores on tree roots. I've been wandering around the forest and looking, you see all these leaves, and mosses, and branches, and you really wonder how do, in goodness name, get the spores down to the roots? And soil is basically a black box. We don't really know what's going on there because it's hard to study and hard to look at individual spore going down because the spore is so small that you cannot see it. And of course, it's also a layered black box, soil is not homogenous all the way through. And the roots are mostly in the upper layer, but still, how do you get through it? But, you know, there are also roots much lower down in the mineral layer, so the spore has to go really deep down to germinate. So two things, rainwater, of course, and also small animals. I mean, invertebrates, mites, insects, that kind of things. I mean, all that is definitely the case. So mites can carry spores around and that's really being shown nicely with this fungus that forms a crust, that fruits on the underside of woods that's lying on the forest floor. So it shoots the spores off, but they don't get very far because they are facing down and under forest, but they really depend on, in this case, mites, the mite have all over its... Fruitbody, on its body. It's also eaten spores. You can see here, the spores on the mite surface, and here is a close-up of that same part of the body of this mite, you see all these spiny spores of that crust fungus. And it turns out that many of the ectomycorrhizal species just have ornamented spores, but not as ornamented as the Tomentella spores in general. So they can be just slightly roughened as in the Cotinarius species, or they can be knobby like gummy bears in an Inocybe. But there are also many small spored Inocybe species, which are equally successful in producing new fruitbodies and new individuals. And then in fly agarics, they have smooth spores. They're not colored and relatives of the fly agaric are not ectomycorrhizal, they are still saprotrophic, they're still able to break down plant material. They also have smooth spores. So there are lots of ways we can think about how do you have spores get into the place of where they want? Is it just rainwater? Are there other things going on? And then another puzzle for me is these dead man's foot spores that are spiny. Yes, but these things, they fruit in the middle of summer, August, September, when it's bone dry. There's no water, there's no insects activity either that I can see, but still they're very successful. And these spores are hydrophobic as well. So we can only see these when you put some detergent with your medium. Of course, there are saprotrophic species with rough spores. Now, most have small spores, but there are also always exceptions. That's basically the general, what you can see, you can come up as trends, but exceptions are always there, so. The next thing is, of course, spore color. Is there a difference in how long the spores can survive outside, depending on the color? Most spores I've got colorless, whites in mass but colorless, but also many colored spores. So like this one, is the rust yellow-brown, rusty brown spores, dark purple brown spores, there are even dark blue spores, and there are also a lot of normal dark drown spores. And melanin is key here. Melanin is this substance that many different kinds of organisms have, and it's really, it's a protection against radiation, UV light in particular, cold, and droughts. The spores that are colored really survive that much better and longer than spores that lack the melanin in the spore wall. And melanin can, in these agaric species, it makes up something like 30% of the weight of the spore wall, so. But it's expensive to make. It's expensive but it is also a good protection. So it is this trade-off with what you want in life, though they don't have a real choice, but that's what it is about. And melanin is also really helpful in the spore walls of dung fungi, of course, 'cause dung fungi, they grow on the dung, the spores gets dispersed, they get on the grass and they'll be eaten by the cow, go through all these four stomachs the cow has with different enzymes, different acidity, they have to survive that, and then they're pooped out on the non-digested parts of the grass, and then they can form a new fruitbody. But yeah, these are really thick walled and really dark. And then they also have that little light spot where they can germinate. So as a similar spot with a plug, probably, so they can germinate through that when they are inside the dung heap. That's a really helpful thing to have. So to end, I would like to revisit the question on how long do these spores remain viable? How long can they be in the environment and still germinate? So most of them have to germinate right away because otherwise, they just vanish, they don't survive. But other spores remain viable for years in the soil, and that's the case, for instance, in pine trees where you have these pine forests of bishop pine. And bishop pine cones only open after a fire. So the spores of these false truffles, which are not really very thick walled or look very durable, they remain in the soil for years waiting for these fire events, when there is this massive amount of seeds coming, and then the seeds and the spores are together, and then they can both germinate and form new pine trees. As you can see here, this whole mass of pine trees that came up after the 1995 fire. So these are 20 years old or so. Suffering, but they came up after the fire because of the waiting spores for them. So many, many years they can remain in the soil and remain viable. With that, I hope I've given you a lot of information, but I hope that in particular, you will look at mushrooms with different eyes. So when you see things like this, you'll say, "Ooh, these are big fruitbodies. "They're probably ectomycorrhizal." Yes, correct. "They probably have ornaments at spores." Yes, that's also correct. And these Russula, how do they get their spores around? So I hope you will look at these things in a new way. And I want to thank you for staying with me and wishing you happy wonderings in the woods.

- Well, thank you Else for sharing your research and your passion. And thank you for continuing to learn with us. We hope you have a great evening and join us back again next week for After Dark Online.