SPEAKER 1: Kathie T. Hodge is an Associate Professor in Cornell's Department of Plant Pathology and Plant Microbiology, one of the nation's oldest and most prestigious departments of plant pathology. She received her Bachelor of Science degree from the University of Toronto-- she was born and raised in Canada-- and the PhD degree from Cornell. Her dissertation was on the taxonomy of a fungal genus that kills insects and leaves their corpses strangely hairy. Doesn't that sound like Monty Python, strangely hairy corpses?
Anyway, I also told Kathie that if she came and talked to us, we were a really fun audience, and we would laugh a lot, and we weren't stiff. And so you've got to laugh a lot no matter what tonight. Kathie is a systematic mycologist who teaches about and learns all about fungi. Fungi are a particularly poorly known group. But so are mycologists, in fact, aren't they? With only about 5% of the species described formally, her specific research focus is in fungal biodiversity, especially of species that are pathogens of insects. And she uses molecular and morphological approaches to discover their relationships and devise classification systems.
Some fungi are useful agents of biological pest control. Her research program has cleaned up the taxonomy of many fungi, figured out where they fit in the tree of life, and described two new genera-- is that right-- I would say genuses, but she says genera-- and 21 new species of fungi. Kathie also directs the Cornell Plant Pathology Herbarium, a world-class collection that documents the Earth's diversity of fungi and plant disease organisms and holds 400,000 specimens, including over 7,000 type specimens, each the first of its kind to be described and named. Will you talk about type specimens? A type specimen is the very first of its kind. And Cornell has 7,000 of them. So we've identified them and we've named them out of those 400,000 specimens.
Kathie teaches four different classes to four very different audiences. This past year she taught a field course on mushroom identification, and a new class called Medical and Veterinary Mycology, in which she shows photos, distressing photos, of extremely unfortunate people with fungus infections; none of which, by the way, will she show us tonight.
This is her response to my request for something personal about herself. Quote, "I've always like very small things. I still have the hand lens my dad gave me when I was about seven. As a child, I made very many origami swans, no bigger than a ladybug. My dad says that a difficult-to-identify land snail I found is the reason that I went into science, a child's wonder of finding that the world is not so well known. I spent a lot of time exploring the natural world at family cottages. But I didn't know anything about fungi until college. In college, I thought I might like to be a wolf biologist, a la Farley Mowat. But somehow the coursework didn't appeal. Instead I took all the classes I could on small things-- insects, plants, algae, bacteria, fungi.
My mycology professor was the most inspiring. So that's the path I chose. Once I wanted to be a science writer. Actually I wanted to be David Suzuki or a more biological Carl Sagan. Now I manage to dabble in science writing via the Cornell Mushroom Blog, a friendly web magazine of stories about fungi. I like teaching. I like to ignite that spark of wonder in my students' eyes.
My husband, Tony Simons, is also a Cornell professor at the Hotel School. He studies the impact of personal integrity on business success. So we don't collaborate much, except we do have a son who is 6 and 1/3 years old, and two big white Samoyed dogs. We live in a house in the woods. There's a stream nearby and it is lovely and fungus-y in our yard, especially this year.
Kathie T. Hodge, a Visit to the Mushroom Planet."
KATHIE HODGE: Hello. Mycologists aren't funny at all. So don't laugh one bit during my presentation today, please. Hey--
So I thought I'd give a talk today about the mushroom planet. I thought I'd lure you in with a kind of universal imagery of fungi spinning in space. And it seems to have worked. Because, boy, there's a lot of you here, you mushroom people. But really what I meant by the mushroom planet is a place that might be familiar to some of you. And this is a view from an early trip by an Apollo spacecraft, a view out over the moon landscape toward-- what's that blue thing? Toward Earth, that's where we are right now. And Earth is, folks, the mushroom planet.
And I'm going to tell you today a little about how mushrooms rule the world, how we are all slaves to them. Let's see, and how-- I'm going to try to convert you to their fan club. OK, so we're going to take a romp through the kingdom of fungi today. We're going to look at a lot of different things, weird things, and just have fun.
This is the planet Pilobolus. And I'll tell you a little bit more about Pilobolus later in the lecture. But I just thought it was a cool image to start out with. Because there's something very otherworldly about fungi, isn't there?
So let's go back to basics to start with. What's a fungus? And probably you have some conceptions of what a fungus is. Perhaps there's one growing between your toes right at this moment, anyone? Anyone? Perhaps there's some moldy food in your fridge. Perhaps you've been flying on a spacecraft and fungi have fogged up the windows. Or perhaps you've just had mushrooms for dinner. I did.
But all those fungi, all those different things, molds and mildews, plant pathogens, human pathogens-- and I promise not to show you any grotesque human pictures today-- all those things have something in common, a few things actually. What do they have in common? Kind of a small set of things.
Fungi are filamentous organisms. So they exist as little threads, basically. They make spores in order to reproduce. You know these things, right? These are familiar to you. They digest their food externally. That's a good one. And that means that instead of eating something like we do, a fungus actually excretes its digestive enzymes into the environment and soaks up the products of digestion. This would be like if my six-year-old threw up on his plate everyday at dinner and slurped it back up, which is-- I'm glad he's not here, because I wouldn't want him to hear the idea.
And then lastly, and I won't dwell on this. Because I know it's very disturbing to many of you. Fungi are actually our own closest relatives. So the fungi and animal kingdoms are very closely related, even though people think of fungi as being like plants. Well, they're not plants at all. They're more like you, not me, you-- in very many ways.
So here's a filamentous fungus. And so imagine all your cells packed into those cardboard tubes that are at the center of toilet paper and stuff like that. That's basically the cell of a fungus. And if you string those things together, you get this filamentous mycelium that you've probably seen growing on your old bread and stuff like that. If you look up close at this picture, you can see little pinheads, which are masses of spores that the fungus is making on it's mycelium.
So think of yourselves inside a crispy paper towel role holder thing-- is there a name for those? Those cardboard tubes, that's basically a unit of a fungus. And if you take that unit, you can make just about any structure with it that you can think of. You can make a structure that's 2,000 acres in diameter, or you can make a tiny fungus that only grows on the back wing of a male ladybug.
You think I'm making this stuff up, don't you? But in Oregon, there is a humongous fungus, a bunch of them probably, we just happen to know about a few of them. They're actually mycelia, single colonies of honey mushrooms that originated probably from a single spore and grew outward and outward and outward, until that single fungus colony covered over 2,000 acres. And this particular fungus is a tree pathogen. So as it grows outward, it kills the trees in its path. And you can actually see the ring of dying trees from outer space. That's humongous.
It probably took it something like 2,400 years to get that big. So we often think of fungi as small things, almost beneath our notice. But sometimes they can be huge.
Another thing fungi I have in common is that they reproduce by making spores. These are the spores of an inocybe species, a little brown mushroom. Oh, they're hard to identify. This particular slide is made from a mushroom that killed a small dog last year. They have these bumpy funny spores, which are used for dispersal and reproduction.
Here's an earthstar. We collected this earthstar from Wee Stinky Glen, which is just across the road on the way to the bookstore. This is an earthstar releasing its spores, just a beautiful thing, but masses-- millions and millions of spores from this one fruiting body. And here are some very small cup fungi that normally kill lettuce growing in your garden. And they shoot their spores into the air at really high velocity, making a cloud of them.
And if a cloud of spores in the air sounds like a bad thing to you, well, it could be. This is a tape lift of spores that we took from one of my student's bathroom ceilings. And it is full of the spores of cladosporium, which is a mold that often grows on people's bathroom ceilings. And people are very often allergic to it. So fungal spores in the air can cause problems for people too, even though I think they're still really beautiful.
So spores, filamentous, external digestion amounts to this. It's beautiful. What gross?
I don't know about you, but I've been picking strawberries lately, and I think I have this fungus in my fridge right now. So this is a fungus. It's a filamentous structure. It grows all like that. It's making a ton of spores that's why it's turning dark right now. And it just pretty much ate those strawberries by first melting them with digestive enzymes and then soaking up the products. That's Rhizopus. That's a powerful fungus. Awesome thing.
So if you are a fungus, and I don't think any of you are, but you might have a few things on your mind. The first is just, can I eat it. And this is a very important thing for a fungus. Because whether or not a fungus can eat something depends on where you're going to find it, where does it grow? Is it in your fridge or is it on your feet? Not the same in both places, don't worry.
And then the second problem of a fungus, because they can't really move-- they don't have little legs or anything like that-- is how do I get to that food source. That's a difficult problem. And then the third problem of fungus is how to keep what you've got just for yourself, nobody else. Mine.
So I want to give you an example of a fungus. And this is my planet Pilobolus graphic. And I'll say right up front here that I'm working with a very fine photographer named Kent Leffler, who took most of the pictures in my talk, and who took this cool picture which I'll show you in bigger scale in a moment, and wrapped it around on itself to make it into a planet. And that kind of sums up the concept of my talk. Everything is fungus.
Who's heard of Pilobolus? A bunch of you. That's good. Pilobolus is a dance troupe, it is a really cool dance troupe. But it's also a really interesting fungus. Kent took this time lapse for me of Pilobolus growing.
Isn't that great? So Pilobolus is a fungus. OK, maybe I should just tell you the back story here. Pilobolus is a fungus that grows on poop. I'll try to get this load again.
So to make this time-lapse, our very devoted teaching coordinator, Dave Kalb, had to actually make cubes of poop and autoclave them, add some agar to them to stiffen them up. So poor old Dave actually worked with little ice cube sized pieces of cow poop to make this time lapse video. So I hope you like it.
Pilobolus is a fungus that grows on the dung of herbivores. And what you're seeing there is it escaping the dung of an herbivore, thoughtfully molded by Dave, by actually making little black spore caps and shooting them off into the air at really high velocity. It's a really amazing thing. And it's doing this because it needs to get its spores off the poop to get it back into some more poop.
So how do spores that get shot off a pat of how poop in the field get into a new piece of cow poop? You think they're carried there by birds? No. You think you think the spores just happened to hit another pad of cow dung?
KATHIE HODGE: Flies? Ooh, that's good. Flies pick them up and carry them? No. That's not right.
AUDIENCE: They're eaten.
KATHIE HODGE: They're eaten. Whoo! Nice job. So if you're a fungus that lives on cow poop and you've got to get back into a piece of poop, the best way to do it is to shoot your spores off onto the grass and have a cow come along and eat you. And then not only do you find a new piece of poop, but you find a steaming fresh wonderful piece of poop in the field . And you get to have the whole thing to yourself. Very good, that's Pilobolus.
Here's a closeup. The sporophores on this fungus, the structures that make those spores, are actually phototrophic. So they can sense where the sun is. And they aim toward the sun. They aim toward the sun at a particular time of day. Because they're always shot off in the early morning and the late evening. And if you think about it, where the sun is in the early morning or the late evening-- have I got it? I've got it backwards-- early morning or the late evening-- that's a pretty strong angle to shoot your spores off.
If you shot your spores off at noon they'd go straight up and they'd come right back down. So timing is everything. But also aiming is good. Isn't that cool? I mean it just seems like such an inconsequential fungus though, doesn't it? Doesn't it? I'm telling you about something that's 2,000 acres in diameter and now I'm going to tell you about something that lives on cow poop.
Well it turns out it's actually kind of a significant fungus. Because it causes problems in the cattle industry. Why does it cause problems in the cattle industry? It doesn't hurt the cows. It doesn't even germinate until it gets out of a cow. So why? Why? Any ideas? What's that?
KATHIE HODGE: It comes out in the poop, and then it shoots off and gets in and goes right through a cow.
KATHIE HODGE: Lifecycle inside the cow? No, it doesn't even germinate inside the cow. It just hangs out, comes out, not toxic, nothing.
AUDIENCE: It kills the grass?
KATHIE HODGE: It doesn't kill the grass. It doesn't Like grass. It only likes poop.
Should I-- should I tell you the answer or should we just move on?
AUDIENCE: Tell us.
KATHIE HODGE: This is the answer. This is the cattle lung worm. And this particular baby is three inches long. And if you're a cow, and you've got something three inches long live in your lungs, it's a bummer. Cattle lung worms for the longest time people couldn't figure out how they got into a new cow. Because they also get pooped out, and then how do they get back into a cow? Pilobolus.
These guys, the babies of these guys, are hitchhikers on Pilobolus. So the little baby lung worms get pooped out. I know it's not a good part of lifecycle. But they climb up those individual sporophores of Pilobolus, and they curl themselves up right on that black cap. And when the black cap gets shot off, they get shot off. And then they too get eaten by a new cow.
So Pilobolus turns out to be a significant vector of a parasitic disease of cattle, and elk, and horses, and other herbivores. Good? Good, it's a cool fungus.
All right, well if you missed anything there, I just wanted to put in a plug for my blog. The whole story of the cattle lung worm and the Pilobolus is online on my blog. And I can't take full credit for this blog. Because I make my students write stories for it. And they do an awesome job. So check it out sometime.
What do fungi eat? So we know they eat cow dung. But in truth, they eat just about everything you could think of. I had a fungus recently growing on the lens coating of my camera, really aggravating. You wouldn't think there'd be enough stuff there to eat. But there they were growing on it. They eat just about anything you can think of. So we thought we'd do an experiment.
You know you can buy those chia pets and you're supposed to smear them with some stupid seeds of some plant? Well we smeared them with mold. So this is Homer Simpson chia pet, growing with Phycomyces on the top there. Phycomyces is an awesome fungus related to Pilobolus. It makes really tall sporophores, maybe 2 inches tall, 3 inches even, a big thing. And we thought Homer looked pretty good after that. What do you think? Do you like? Genius, isn't it? Genius. This is why they pay me the big bucks here.
But notice on Homer's forehead, there is something that looks like stubble. So let me just tell you that to get Phycomyces to grow, we actually smeared Homer's head with nutrient agar. Yes, sorry, kind of cheating maybe. But nutrient agar, so that's why Phycomyces is growing on his head. But on his forehead and his eyeballs, there's no nutrient agar. It's just terra cotta. So it shouldn't be very tasty for a fungus. But if you look up close, it turns out there is a black fungus growing all over Homer's forehead, and over his eyeballs, and nose, and down the back of his neck like stubble.
Here's the Phycomyces. It's a beautiful pin mold that grew on his head. And here's the thing that grew on his forehead. It's Aspergillus niger. Ooh, Aspergillus niger is like one of the most important fungi in the world. Why?
Well, it has many powers. It can kill onions. It's good at that. You find it in soil. It's pretty good at that. What else? Do there anything else? This fungus is an industrial workhorse. It is used to produce many natural products in giant fermentation tanks the size of this room. You can put lots of different genes into Aspergillus and make it crank out lots of different things that might be of interest to you. Like for example, citric acid, I know you probably all thought that citric acid was a product of lemons that some little old lady was squeezing in some sunny grove somewhere. But, no. Citric acid is a fungal product.
So most of the citric acid production in the entire world is produced by that little black fungus that grew on Homer's forehead Aspergillus niger. And citric acid is in lots and lots of products, if you read ingredient lists. So any kind of Mountain Dew or Sprite or anything with a little bit of a lemony hint in it, fungus. Now you know. By the way, this is too much soda. If your fridge looks like this, that's too much.
What else might you find in your fridge that is a fungal product?
KATHIE HODGE: Yogurt, no. Bacteria, blech.
KATHIE HODGE: Cheese, yes very good. Some blue cheeses. What else? Yeast. What can you make with yeast?
KATHIE HODGE: Bread. You all say bread?
KATHIE HODGE: Beer, wine. Wine, so I think that Aspergillus niger and yeast, Saccharomyces cerevisiae, are having some kind of duke-it-out showdown for who is the most important fungus. Because yeast is one of the most common ingredients in lots of things that we eat, yeast extract, yeast products, beer itself, wine, bread; lots and lots of stuff. Fungi bring us beer.
So fungi are useful to us. Where are they in nature? When you think about a fungus, where would you look first?
All over the place, everywhere. There's probably some in this room. Take a deep breath. Well, most people when they think about fungi, they either think about their basement, which I don't want to talk about; or the forest. And indeed, the forest is an awfully good place to look for fungi. And this year I've got to say it has been just amazing for fungi.
There are mushrooms all over the place. We stumble on them as we walk across the lawn. They're just blasting out everywhere. It's great. There are lots of fungi in the forest. And I'm going to go through just a handful of interesting ones. And we'll talk a little bit about the roles they play in the ecology of our planet.
This is Tylopilus felleus. It looks beautiful, doesn't it? It looks almost like a King Bolete. But if you make that mistake and eat it, uck, you'll ruin your whole meal. Because just a little taste of this is strongly bitter. It tastes terrible. I can't recommend it.
But this fungus is actually a really important forest resident, because it's mycorrhizal. It's hooked up to the roots of trees underground. So the filamentous mycelium of that fungus under the ground is actually involved in some kind of secret handshake with trees. And there's an exchange going on there. The tree is providing sugars to the fungus and the fungus provides what to the tree? Good stuff-- mineral nutrients, water even, important stuff that trees need. And in fact, most trees in the forest here are mycorrhizal. Rival Most herbaceous plants are mycorrhizal. And forests in this area depend on mycorrhizae to survive.
So you can't grow a forest in a sterile environment without these symbiotic partners. I'm really serious. People never believe me when I say this. And whoever taught you guys botany, and didn't tell you about these fungi, out with them. Bad. So here is a picture just to prove what I'm saying. This is from the cover of an important book on mycorrhizae. So there's a little pine seedling there. And see the roots?
Well, the roots of the pine or the yellow bits. But all the white bits are the mycorrhizal fungus. So you can kind of see the secret handshake kind of places where the mycorrhizae are formed as little nodules or lumps around the roots. And then out from those lumps spreads this fungal mycelium that's gathering nutrients, breaking down soil with external digestion, and having this conversation with the plant. And not only that, but this fungus attached to this pine tree might be hooked up to 10 other trees right near it. So there's this nutrient exchange going on under the forest floor.
My colleague, Paul Stamets, calls it, nature's internet. And he imagines the planet as being just a giant mycelial mat, everything hooked together. And there's some truth in that.
So mycorrhizal fungi are really important in forest function. They're important in supporting tree growth, but they're also important in breaking down leaves that fall, so that they get used up in part of the carbon cycle. Has anyone ever eaten this fungus? I like it. It's one of my favorite fungi. It's the black trumpet, Craterellus. Although if I'm walking in the woods and I find someone who's collecting some, I always call it the trumpet of death. Because then sometimes they give it to me.
But this should be fruiting around here just about now, and it's a beautiful flavored mushroom, another mycorrhizal fungus, by the way, and so is this, Cortinarius iodes. This is a slightly poisonous mushroom. But it's good for the forest. You might mistake it for a blewit if you're a mushroom hunter. Because it's got that same purple-y thing that blewits do. But it's a mycorrhizal thing with brown spores.
And then here's a little green mushroom that I looked for, for a long time, and finally found last year right in my yard. This is the parrot mushroom. It's only maybe an inch and a half tall, but very beautiful green thing.
Some forest mushrooms are filled with evil and will kill you. Around here we have this beautiful pure white mushroom, the Angel of Death. It was named by the first mycologist here at Cornell, George Atkinson, back in the early 1900s. And we've seen it kill several people around New York state, just in the last few years. Because it just looks so beautiful and succulent and it smells wonderful. You can read an account of an almost fatal poisoning on my mushroom blog by a local resident who ate this by mistake. It's a good mushroom to know. It's a close relative of this other mushroom, the Death Cap, so Destroying Angel, Death Cap. If a mushroom has a name like that don't eat it.
OK? The Death Cap is probably responsible for more mushroom poisonings in the world than any other mushroom. It's not native here. It was used by the Romans to poison their emperors. And unfortunately it's been introduced several times in North America. So if you live near Rochester, there's a nice patch of it up there. There's a patch in New Jersey. There's a big patch in California. So look out. It's not here in Ithaca yet, but any day now.
And both the Destroying Angel and the Death Cap contain the same big nasty toxin. And I put this up here for those of you who are geeks of some kind. I'm sure there probably aren't very many geeks here. Oh, wait. I see some.
This is the toxin of the Amanita mushrooms, and what it basically does is it stops yourselves from making proteins. And that's pretty much how cells function. So this thing you eat it. It gets in through your gut and it just shuts down your cellular metabolism. And eventually you die. Usually you die of liver failure, because livers are pretty metabolically active. And if you shut one down, you're going to die pretty soon. It can cause kidney damage. It strips the lining of your intestines. It causes some brain damage. It's a really serious toxin and there's no easy antidote for it.
So the common treatment for Amanita poisoning, liver transplantation. Ooh, so someone else has to die so that you can survive. So like I said, good mushrooms to know.
There's a close relative of the Destroying Angel. You may know this fungus. A slug got into our time-lapse chamber. This is Amanita muscaria. Around here, we have yellow Amanita muscarias. But you may know this fungus from your Playmobil toys, your experiences with gnomes, as a red-capped fungus with white spots on the top. It's kind of iconic, a Super Mario Brothers kind of mushroom. Around here it's yellow and it's not fatally poisonous, but it does cause some interesting hallucinatory effects in people who sometimes take it recreationally.
I can't condone that. But some people do. I can tell you this mushroom is up all over the place around Ithaca right now. I know this because I've seen two different dog poisonings with this mushroom in the last week. Yes, dogs are not very smart. And sometimes they eat mushrooms that make them quite ill. Don't feed this mushroom to your dog.
But this is one of those mushrooms that has a long cultural use. Gordon Wasson decided it was a key to interpretation of the Rig Veda, a religious document of India. It's been used for a long time by shamans around the world, who-- and I feel like I'm saying too many things that are just embarrassing. But I think I'll forge ahead. What I was going to say was that the shamans of Siberia discovered that this mushroom's toxin or potent molecule, whatever you want to call it, is excreted in urine.
So the urine of people who ate this mushroom was sought after as an hallucinatory agent by Asian shamans. And I think that in some Siberian tribes the tradition was to feed the mushroom to the women who then suffered kind of the ill effects of the mushroom, and then save their urine for the men, who just enjoyed the good parts. I really kind of wish I hadn't said that now.
OK. So that's another mycorrhizal mushroom. But there are other kinds of mushrooms in the forest that are doing different things. They're not all hooked up to trees out there, right? Here's one, Hypholoma, the brick cap, that is a pretty good edible mushroom. And it's actually eating trees. So there is good and the bad. You can be helped by a fungus or you can be eaten by one. That's the way life goes.
Brick caps, their mycelium is growing inside the log and actually degrading the structure of the wood. And fungi are really important players in this game. Because wood is tough to degrade. And certain fungi really have it figured out. So fungi are the dominant life form degrading wood. And without them, we'd be just buried in sticks or something.
This is my son with a big edible wood rotting mushroom. This is Hericium americanum, pretty nice. They've got kind of a seafood taste to it. So yeah, have a look for this. It's fruiting around here pretty soon. This is a little wood rotting fungus, hairy fairy goblets. I like hairy things in general. And this, what is this? This like a whole planet of fungus. So this is a little butternut seed, like a butternut that a squirrel has chewed open. And it is the entire home of this little bird's nest fungus.
And if you look kind of-- if I can use my pointer here, right here. See this guy? See there's two little eggs peeking out. And those eggs are little packages of spores that this fungus makes. It's a wood degrader. It'll degrade anything kind of woody, like this butternut seed, trees, sticks, straw; whatever you give it. And it's waiting for rain. So it makes these little goblets with little eggs inside them, and when a raindrop splashes in there it splashes those little eggs out and they presumably land on new twigs, wood, and eat it up.
But the cool thing-- OK, you ready? The cool thing is that each of those eggs has a little string. And at the end of the string is a sticky bit. So as the egg gets splashed out, it hurtles through space and usually from my class sort of pantomime this. But I'm a little embarrassed to do it up here. But you can imagine me flying through the air with a string behind me with the sticky bit on the end-- I'm doing it-- that sticks onto something and then [WHOOSH] that tacks the egg right down to the substrate. They're perfect, beautiful little fungi. And luckily for you, Cornell likes mulch. And these fungi like mulch. So you'll see these all over campus in the bark mulch under the trees. I love the Cornell gardening people.
There's other weird stuff going on. So what have we got? We've got mycorrhizae. We've got wood rot, we've got bird's nest fungi, and then there's this. Someone sent me this picture early spring. What is that? And it's big. It's like a big storm. It's covered in beautiful orange yeasts. You thought yeast was just for beer. But no, there's many, many species of yeasts. And this particular yeast is orange and it loves sap. Yeast in general like sugary things. And they grow as single cells in an oozy-gooshy way, almost like disgusting bacteria. So this is a yeast in the forest you may find.
This is a bolete. It's called the ash bolete gyrodon merulioides. It's a beautiful thing and you could eat it. But it wouldn't taste any good, but it wouldn't die. It depends what breed of mushroom hunter you are. There are some mushroom hunters who they just want to eat everything they can lay their hands on, no matter how disgustingly moldy it is. They want to eat it. This one they would eat. It just doesn't taste like anything.
But the cool thing about this, OK, for a long time we thought this fungus was mycorrhizal. We thought it hooked up to the roots of trees. But it does not. So why is it only associated ash trees? Oh, it makes these little BBs, like little tiny gray spheres in the soil. You can find them right under these mushrooms. And those BBs are hollow.
And in some of those BBs-- this is a secret, so don't tell anyone outside this room because it's privileged knowledge-- inside those BBs is a little bug that is sucking on the roots of the ash tree. The fungus makes a little house for it. And in return the bug gives the fungus sugars that it extracts from the sap. So this whole mushroom is made from the pooped out honeydew sugars of root-feeding ash aphids.
Doesn't that sound improbable? Do you think I am just making this stuff up? Sometimes I have to pinch myself.
Well if I hadn't already crossed the bounds of decorum, I thought I'd show you this. I'd rather not say anything about this. Except I will say these are maybe about six inches tall. Oh, the fly. You guys OK? All right.
I don't like big fungi. I think they're vulgar. So instead I work on very little fungi, the littler the better, I'd have to say. I like molds a lot. I think mushrooms are kind of just-- I don't know. They're just too big. So here's a mushroom that I'm kind of fond of, although it's a little bit big. This is mycena species. I have no idea what it is.
Here's another mycena species. This one's even littler, if you can believe that. And it grows exclusively, apparently, on the bark of basswood trees. And so if you go out there with your father's hand lens and scrutinized the bark of a basswood tree, well, two things will happen. One is your neighbors will think you're crazy. Trust me. The other is you will maybe find this fungus, which is really exciting, because very few people in the world have seen this fungus. And you could be one of those people. I find that exciting.
So I said this fungus was small. This is how small that same mushroom was. That's my fingertip. So now we're getting to the right scale, aren't we? I'll tell you the problem with working on very small fungi though. The problem is that very few of them are known. Sure, all the big vulgar things have been named, just like cheetahs and elephants and stuff like that. But the little fungi are not very well known.
So I wanted to just give you kind of a sense for how little we know about fungi. These orange balls are representing the known fungi. These blue balls represent the fungi that we don't know about, but we guess might exist. And I have to admit we're extrapolating horribly about these blue balls. Because it's really hard to know how many things you don't know, right? And yet, this is what we think. We think that may be only about 5% of fungi are known. And we think that about 95% of fungi are unknown, meaning that they don't have names. If anybody's ever seen them, they haven't recognized that they're different. They're out there somewhere. We don't know.
A colleague of mine went to Antarctica recently and looked at the degrading shacks built by our Antarctic explorers, and found a ton of new species degrading those shacks. Like who would have thought fungi, new species of fungi in Antarctica? They're everywhere. They're here on the Cornell campus, I can tell you. They're here in Ithaca, despite 120 years of my mycological legacy here. They're all over the place.
And so my research program has focused on pretty small fungi, and mostly as you learned in my intro, fungi that kill bugs. So here's one, Isaria sinclairii, that kills little bug larvae. So down there at the bottom is a cicada larva. They live in the soil. And fungi turn out to be important pathogens of insects. Thousands of fungal species kill bugs. That's what I work on. And just in the last eight years or so we've described about 21 new things just from bugs. Who's have thought?
And fungi that are very small have their own kind of particular beauty, I think. They do things in weird ways. So here's a small wood rotting fungus, bulb allomyces is one of its names, or we could call it Aegerita. And it focuses on pieces of wet wood. You'd think just about any fungus could eat wet wood. But the trick is, how do you find a piece of wet wood that's semi-submerged in a stream and stick your spores on, and then start to eat it?
Well what these fungi do is they make these big spores. These are huge. They're almost-- I don't know-- a millimeter in diameter. And inside each of those balls is trapped air. So if you look at this spore under a microscope it looks like a cauliflower, and it's got all trapped air inside its branches. These spores are made to float. So when wet weather comes along and there's floods, these spores float to the surface. And when things dry out, they sink down and whatever leaves are underneath them, whatever sticks and branches, they get there first. Aegerita, a beautiful thing.
I also tend to like parasitic things, but I know why. I think maybe I should talk to a therapist of some kind. Because seriously I am always talking about poop and sex and dead cadavers. Are there any therapists here that I could talk to afterward? Maybe you?
All right. So here's a bird's nest fungus, insanely large thing, maybe almost an inch tall, grotesque really. It's a different bird's nest fungus than the one I showed you earlier. But it's wearing some kind of leg warmers. The leg warmer part is the part that I like. It's actually a specific parasite that only attacks birds nest fungi. I've been looking for this fungus for years, but I, again, found it in my front yard just last year. Last year was a good year for me.
This parasite, I don't have much to say about it. But it just astonishes me that there could be a mold that grows only on bird's nest fungi. And there are very many fungi like that I can tell you. So now I'm just going randomly through the fungal kingdom at this point, showing you very small things. And therefore I thought you might like to see these slime molds. Whoa, and look at that.
Oh, so pretty. So this is kind of an affirmative action kind of slide or something like that. Because slime molds are not fungi. So I'm putting them in here just because for a long time, we thought they were fungi. And honestly, they are awesomely cool. But they're not fungi. They're actually amoebae. So slime molds, well, there's a couple of kinds. But I'll give you one example of a lifecycle of a slime mold. Slime molds eat bacteria. Blech, who likes bacteria? Let them eat them, good.
They crawl around as an amoeba and eat bacteria and junk like that off the surface of wood and stuff like that. They don't make hyphae. They don't make-- well, they do make spores. But they're not much like a fungus. They're like a giant oozing single cell. They crawl around and eat all that stuff. And when they're done, they're full, I don't know why, they call to each other using chemical signals. They grow towards each other. They crawl toward each other. They merge their cellular contents into a big giant amoeba. And then that big giant amoeba miraculously converts itself into some kind of fruiting body, maybe like this. Or maybe you've seen this.
If you're someone who looks at gardens and mulch a lot, you've seen this thing. It's like a disgusting pancake on mulch, kind of pinkish, black inside. Or if you catch it a day earlier, it looks like dog vomit. I'm just not very presentable, am I? It looks like a big yellow oozing mass of snot. That's what it looks like. And these are all over campus right now they're giant amoebae, is what they are.
So next time you see one instead of going like, ew, big massive of dog vomit; you can say, whoa, cool, single giant-celled amoeba. Awesome. This is a little guy. It's a cellular slime mold. And it makes those little purple heads which are all full of something that looks like spores, which is why people thought they were fungi for the longest time. But instead of germinating into hyphae, those spores germinate by hatching out a little amoeba that crawls away, a beautiful, beautiful thing.
Oh, and just gratuitously, I'm going to show you one more slime mold video. This one's got a lot of water on it. But see those little slug looking things crawling around? Those are giant amoebae. So this is a different species. I don't know. There's just-- life at this scale is just a whole different world. It's just amazing to me what's going on down there. Nobody knows about it. How can that be? It's just so exciting.
Lichens are fungi. So these little green crusty things you see on trees or on rocks that seem to live in places where no other organism can survive, they're also partnerships, just like mycorrhizal fungi. Lichen partnerships are between a fungus and little single-celled algae, so green cells that photosynthesize, use the sunlight to make sugars, which they trade with their fungal partners in exchange for some minerals, but also shelter. So lichens can grow in places where no fungus can grow by itself, and no algae can grow by itself. And they're really beautiful.
I just wanted to say a word about these circular photographs that I've been showing you. They're also the product of my genius colleague, Kent Leffler, who's the photographer for most of this stuff. And this is the rig he uses to photograph those round pictures. It's a camera with a borescope stuck on the front. A borescope is something like your doctor might use if you're having knee surgery. They stick it right into you and then they can look around in there, pretty neat. Some kinds are flexible, but this kind is a rigid borescope, high optical quality that we take out in the woods together. And we stick it in all these weird places and look at very small things with it. It's been a really exciting project.
And we did this project because we wanted to get a different view of life. I think we're kind of size bigots, most of us. We think that the right size is maybe about 5 foot 5 inches tall. That's what I think. And anything smaller than that just seems like not worth looking at. So we use the borescope to get this insect eye view of things. And this is a big fly, a bee mimic. And it's been just a really fun project.
So here is Kent out in the field with the borescope. It's kind of a weird way to take photographs. But it works really well. And this is Noni Korf, who's been helping us with the project as well. And together we put together this book, which you can actually buy, if you would like to see a different view of life. And it includes some of Kent's really fine photographs with some very serious little writings by myself. As you know, I'm an extremely serious person.
So here are just some more views of very small fungi. And you can see how if you can look at life from this small perspective, you get a whole different sense of the world. So here is our planet from the perspective of a fungus, where mushrooms are towering gigantic things like redwoods, and lichens are beautiful undergrowth. Here are the teeth of a beautiful jelly fungus that grows on wood. This is called Pseudohydnum, the jelly tooth fungus. I can eat it, but it doesn't taste like anything.
And we've discovered some surprising things out there on our borescope expeditions. So this flow of baked beans is actually a slime mold. It's just setting up. So it's just turning from an amoeba into a mass of little round fruiting bodies that will contain the spores. But right now if you squish them, they make really good face paint. But Kent took this picture in the field with that setup I showed you. And we didn't even realize until we got back to the lab with a big monitor that it had this mold growing on it. A parasite, one of my favorite things. This is a rare slime mold parasitic mold. It only grows on slime balls. And there it is Blistum tomentosum. It's a beautiful thing.
So just using the borescope has allowed us not only to see the world a little bit differently, but to encounter things we might not have encountered before. There it is up close. This is the scale at which I wish I existed. Wouldn't that be fun? It would be very dangerous, of course, but it would be awfully fun.
So this is my view of the mushroom planet. Just about anything is fair game for a fungus. I defy you to think of something that I can't think of a fungus that will grow on it. And the view of life from this scale is just a beautiful and awesome one. And I hope that you all get to appreciate it in some way that doesn't involve fungus actually growing on you. This is a fungus rotting my cherry tomatoes. My dog is also a mycologist. And I just wanted to say thanks, thanks for coming tonight.
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Join Cornell mycology professor Kathie Hodge on a journey into the world of mushrooms, molds, and other fungi.
Are fungi friends or foes? How do they do what they do? You'll encounter much that is strange on this virtual biodiversity tour, and you'll get to know our planet from a refreshingly fungal point of view.