Creatures That Don’t Conform

The earth is stitched together with slime mold, and we are stitched with slime, too. But we have overlooked this fact of life.

My own creeping awareness of this began with a photograph.

I was reading a copy of New Scientist magazine in October 2021 when I turned the page and paused. What on earth was that? It looked like a gelatinous raspberry, but each drupelet was elongated and stood erect on impossibly spindly black stalks under a hat of the cobbled surface of a licorice spog. To top it off, a wood louse seemed to be sucking part of the crimson jelly into its mouth. I read the caption: it was a “slime mold,” photographed by Barry Webb, in the south of Buckinghamshire, UK—not far from where I live.

Slime mold? I’d heard vaguely of slimes that had been used for experiments in labs to solve mazes, but this bright berry-like structure was new to me. I searched online and found a gallery of images Barry had taken of other species.

I couldn’t believe my eyes.

Iridescent rainbow orbs bursting into tangerine spun sugar. Pearly spheres of goo. Sorbet corn dogs leaning into one another with matching bouffants. Bright yellow blackberries. A bunch of Mr. Blobby’s babies. Golden goblets overflowing with effervescent honeycomb. Opalescent spherules in crinkled sweet wrappers. Amaretti flecked with flakes of soap. Honestly, go and check it out if you don’t believe me.

These intricate structures—netted, patterned, striated, globed—were, I learned, the fruiting bodies of myxomycetes, the scientific name for slime molds. Slime mold is a common name which is an attempt to describe organisms that defy simple categorization. For a while, it was thought they were fungi, so they were once classed as such (hence, myceto-, meaning fungus). But they are not fungi at all, and they live much of their lives like an animal.

Yes, that’s right: like an animal. Myxomycetes have two main life stages but four in total. First, they exist as amoebae and dwell in high numbers in soil. Then they become a free-moving, hunting, foraging, predating, exploring organism in the plasmodial stage. We know more about this stage because scientists and artists have been able to observe the behavior in laboratory settings, showing that plasmodium can solve various complex problems, such as finding an optimal way home through mazes, or, famously, mapping the car and rail networks of Tokyo more efficiently than humans are able to. We have already learned a lot from slime molds: for example, astronomers have only been able to map the mysterious dark matter that holds the cosmos together with algorithms inspired by plasmodium.

In this creeping stage, slime mold plasmodium is often bright yellow, though it can be orange, red, or hyaline. It can spread for a few inches, or several square meters. Plasmodium feeds on bacteria, fungal hyphae, spores, algae, and lichens. Then a radical change occurs and it morphs into fruiting bodies, many of which are brightly colored and distinctive. The fruiting bodies tend to be between one and four millimeters high, visible to the naked eye but much more visible with a hand lens or loupe, I read. Then the slime mold sporulates. Spores carry forth on wind; air currents; in the bodies of others; and in water. The cycle continues.

Describing slime mold in 1868, biologist Thomas Huxley asked: “Is this a plant, or is it an animal? Is it both or is it neither?” Today, we still don’t really know. Myxomycetes are currently placed in the kingdom Protista: Enigmatic creatures that can’t be placed easily in boxes. Creatures that don’t conform. Creatures that defy our understandings of the world. Creatures that spill ooze through constructed human boundaries. Creatures that are at once individual and then collective.

The fruiting bodies in Barry’s gallery were more beautiful than any flower or fungi, any fruit or bird, that I had set eyes on. And although his photographs were of organisms just up the road from me, I had never seen any of them before. How could such beauty be lying within reach? I had to find out. I ordered a couple of books and discovered that they are actually very common.

Myxomycetes live anywhere there is organic material. They grow in abundance in temperate forests and woodlands. On leaves, logs, wood chips, bark, fence posts, compost, twigs, decaying stumps. They live on flowers and vines in the canopies of tropical rainforests and at the edge of snowmelt in Arctic and Antarctic regions. In wet forests and towns and on the bodies of the helmeted iguana in Honduras. In deserts, mountains, remote islands, and heathlands. So, in other words, everywhere. While there are a thousand or so known species, it’s likely that there are more.

Apparently, I learned, if you place a piece of wood in a “moist chamber”—a damp petri dish—you can grow slime mold at home. I started taking twigs, little bits of fallen wood, from my garden and local park and trying out this technique. Each morning I would check, eagerly, for some activity.

Weeks passed. Nothing happened. I looked in the woods. I couldn’t see them anywhere. Were the slime mold people having a laugh? Where were all these beautiful structures? Why couldn’t I see them?

One day I spotted a small piece of bark on the forest floor with some fluffy yellow tendrils on it. I took it home and placed it in the petri dish for one last try, thinking it might be a sclerotium—the dormant, dry state of plasmodium that will wake up when moist.

I forgot about it for a few days, until one morning I remembered and decided to have a look. Bright yellow rivulets of wet slime had appeared! It looked so vital. So gooey and unctuous and alive.

The next morning, though, it was gone. Completely disappeared. If I hadn’t taken a photo, I might’ve thought I’d imagined it.

I turned the piece of bark around wondering what I’d done wrong. But then I noticed a few beads, tiny glowing buttons. I grabbed my hand lens—a jewelry loupe—and zoomed in. A number of lemony gold globes, the surface mottled and bespeckled, had formed and were sitting together on curved toffee-like stalks. That which seemed dead—the sclerotium—had metamorphosed into something unimaginably beautiful.

I was hooked. How could I find more? Online, I saw that myxomycetes were having a cultural moment. Instagram and other sites were filled with people posting photos and joining groups of appreciation and identification. Why were people so drawn to them today? I wondered. Could we learn anything from the slime molds? What could they teach us in this moment of change? Could we see the world more clearly alongside them? Could we think differently through them? What would they say if we tried to listen?

The trees were laden with acorns on the day I first traveled to meet Barry Webb and his wife, Gill Ferguson, also a photographer, for a slime mold safari in their nearby woodland. It was a mast year—a year when acorns are abundant—and the ground crackled with their tough shells. I met them at a coffee shop in Burnham Beeches, a national nature reserve in the South of England. Gill was wearing a T-shirt with an image of slime molds, which I was able to identify.

Both Barry and Gill talked enthusiastically about the beauty and diversity of the fruiting bodies, and I started to pick up the names of the major groups: Stemonitis, Physarum, Arcyria, Cribrarium, Trichia, and Lamproderma.

Since first finding slime molds in 2019, Barry had created an incredible body of work that earned him a significant online following and multiple photographic award nods. He described to me how serendipitous and unpredictable a steady relationship with “myxos” could be, but also how ubiquitous they were. How the fruiting bodies start out brightly colored and then become rapidly darker. How lucky he had been to capture that moment of the wood louse feeding on the raspberry Stemonitis. How he would check in frequently to capture different moments of their process, but it all depended on the weather and conditions. The long dry summer had been hostile to slime molds, which need moisture to thrive, but heavy rain could wash away much of the delicate fruiting bodies.

We met on a dry day following a few days of rain. Perfect. We set out into the forest. I was hoping I might see an actual slime mold in the wild, but I imagined it might take some time.

We had been walking for a couple of minutes when Barry knelt down and called out, “Coral slime mold!” Puffing out of a decaying log in the leaf litter were clouds of bright white honeycomb. Later, when I looked at Barry’s close-up images of Ceratiomyxa fruticulosa, it looked like gelid icicle fans. “Wolf’s milk!” said Gill, a few meters away. On a bare patch between bark were nodules of bright orange and gray, spongey globules that looked like tiny bean bags.

I watched how Barry used his torch to illuminate the underside of logs as he pointed out the kind of damp wood to look out for: moist, a bit decayed. How his and Gill’s eyes roved, looking for patterns and shapes and flashes of color. We walked towards a large fallen log and Barry pointed out scores of beads of black ink on stilts. Later, a close-up image showed their iridescence, invisible to the naked human eye. On our way to a clearing, I started to notice that the coral slime mold was abundant. In a new location, I noticed the shape of a chocolate-brown Stemonitis, and we found wolf’s milk again and other species. My eyes were starting to learn slime mold. My ways of seeing were altering, thanks to my new friends who were showing me what to look for. What was once invisible was quickly becoming apparent. It challenged my sense of perception. How little and how limited was my vision! How vast was the unknown world.

Have we discounted slime molds because of their association with the bogeyman, slime? As Susanne Wedlich has pointed out in her book Slime: A Natural History, we can try to ignore slime—matter which exists between solid and liquid—but it’s part of our nature. It is part of our bodies: mucus lines our every organ and acts as protector, hydrator, selective gatekeeper, lubricator, and food source for friendly bacteria.

It is essential for most every organism’s survival. Still, it grosses us out.

“Our all-too-often highly emotional response to viscous materials can lead to ignorance as we forget that slime is the very foundation of our biology, an essential for our health and our environment,” Wedlich writes. Slime is everywhere, earth’s cog, as she puts it.

Scientists attempt to study slime but often struggle to make sense of or unravel how it, or they, works.

Culturally, an ambivalent relationship with the ambivalent slime persists. On the one hand, we view it as abject and rank—a sign of decay, death, rot, the feminine; indeed, Sartre famously despised it—but on the other, we find it exciting and amusing.

When I was growing up in the ’90s, children could buy little pots of pink or green goo with their pocket money; game shows ended with people being gunked with slime; and films and TV shows inspired by The Blob, like Ghostbusters and The Secret World of Alex Mack, were popular.

Certainly, there is a growing love and interest in slime molds—a more palatable form of slime, perhaps, even though they are strictly viscous—and they have inspired poetry, art, music, queer studies, and literature, including the science fiction of Octavia Butler and the collaborative art of Heather Barnett.

Margaret Price’s poem “Slime Molds Have Eleven Sexes” was published in The Gay & Lesbian Review in 2003. “Beyond the binary, not hung up,” it goes; “and probably wearing tiny berets.” Which some of the Physarum absolutely do. That we now believe, only twenty years later, that slime molds actually have 720 sexes illustrates how we are still on the frontier of myxomycetes discovery.

Price first learned about slime molds in 1995 at the University of Michigan in a class called “Behavioral Biology of Women,” taught by the anthropologist Barbara Smuts. She was twenty-five at the time, had grown up in a “mostly male, extremely sexist environment,” and was struggling to come out as queer and as genderqueer. “I never forgot that same-sex relationships and diverse sexes were not deviant,” she wrote to me. “They are in fact normal across many species.”

In one of the guest lectures, she learned about slime molds. “At home, I wrote the poem quickly. It made me laugh and made me feel more seen, more known, in the world.”

While slime molds have been measured by scientists and given tasks in the lab, it will be interesting to see how they entangle with culture in different ways and continue to influence ways of being. How might a kinship with slime smother our inadequate but still-dominant ideas about the world?

Sarah Lloyd, a leading slime mold researcher based in Tasmania, thinks that they are the most remarkable organisms on Earth. In her book Where the Slime Mold Creeps, she shares her fascination through descriptions and photographs of the many species she has found in the forest around her home, including a number new to science, and one named after her. Her close study has brought the hidden ecology of myxos to a wider audience.

Her observations are thrilling. Phaneroplasmodium can travel several meters within days! Protoplasm can flow in one direction, then stop and reverse! The fruiting bodies form when plasmodium breaks into a “number of small portions,” which develop into stalked units.

One evening, I talked with Sarah. A longtime bird-watcher and author, she started looking for, identifying, and photographing slime molds twelve years ago, and hasn’t stopped.

As she began looking closely at them, she was surprised by two things: one, how common and prolific they were; two, that they were not easy to identify or know.

Some years she might find lots of fruiting bodies on the same log—a “hotspot”—but the next year there might not be any. Why this happens remains a mystery to the scientific community. “They’re persisting in the log,” she said, “so do they persist as spores or sclerotia, the dormant stage of the plasmodium? We just can’t answer these questions because at both stages they’re microscopic.”

Another mystery is why slime molds have evolved to be so bright and beautiful. What function does the iridescence have? This has not been studied at all, but she has a theory. She thinks it’s a protective layer which may strengthen the membrane and protect the spores from rain, which makes them vulnerable to fungal attack.

I put the question to Steven L. Stephenson of the University of Arkansas, who has studied slime molds on all seven continents for the past forty-five years. He considered whether slime molds’ iridescence and colors could be attracting the attention of the numerous vertebrates associated with them, but, as not all are eye-catching, it is impossible to say. “Perhaps there are factors that aren’t apparent to humans,” he wrote to me.

Aren’t apparent to humans. I noticed how often this sense of the sublime unknown came up when people expressed their love and interest in slime molds. I asked Sarah how they had changed her life. She said they gave her an “appreciation of how much we don’t know.”

“People are only just realizing the importance of fungi with this wood-wide web, and the time for slime molds has come,” she said. “People are going to realize just how important they are in the scheme of things.”

She explained to me how important slime molds are in the amoeba stage in the soil. The amoeboflagellates of myxomycetes can account for around 50 percent of soil amoebae. Within one cubic centimeter of wood, thousands will live. What are they doing? Feeding on bacteria, returning nitrogen to the soil, recycling nutrients, and keeping the populations of microorganisms in balance.

Currently, the relationships between slime molds and others, and their role in ecosystems, are understudied and incompletely known. But with four visible life stages, each one will have a different niche in habitats and wider food webs.

One fascinating discovery Sarah has made, because of the internet, is that some species sometimes fruit simultaneously in the Southern and Northern Hemispheres. But we don’t know what conditions or triggers lead to this. We also don’t know much at all about spore dispersal: how far are the spores traveling, and how many other organisms are they providing energy for?

“From all indications, though,” Steven told me, “slime molds in the soil play an essential role in nutrient cycles.” Lots of invertebrates feed on slime molds; lots of slime molds feed on other organisms. Springtails (Collembola) are closely associated with slime molds and might only exist because of this relationship. These mesofauna, or soil animals, are the engineers of the earth, the carers and producers of the soil which gives rise to all life. Slime mold and its friends, and feeders, are tiny and vulnerable and easily overlooked, but they are the building-blocks of the Earth’s existence.

In addition to food, slime molds also offer shelter, breeding places, and nests for various species of insect, including beetles and flies. A number of fungi species only occur in association with slime molds (they are myxomyceticolous). In Mexico and Ecuador, human populations use certain species of slime molds for food—fried, often with eggs—and for medicine (wound healing).

“Slime molds are part of our world, and I feel that it is important to maintain the habitats in which they occur—which also mean that we maintain these habitats for other organisms,” said Steven. Forest fires, the destruction of woodland homes, and the systematic replacement of diverse broad-leaved forests with conifer plantations in the industrial world have a particularly devastating impact on slime mold populations.

Even on a small scale, when dead wood is cleared away, when wooded areas are tidied up, diverse webs of life—with slime mold as a central actor—are destroyed. The presence of slime molds is a sign of health, of energy, of organic material, of life.

The more we learn about the microbacteria that are part of us (that are us?), the more we find out how important it is to have a diversity of “old friends,” as they are called. We don’t know if or how the spores of slime molds that humans have evolved alongside for millennia, or the microbacteria associated with slime molds, interact with us, but it is possible if not likely that they do.

Digital photography, social media, and perhaps even the Covid-19 pandemic, which fixed people to their local areas, has given rise to a new noticing of slime molds. I wonder if there is also a growing appetite for transcendence and awe in our wonder-depleted world.

I asked Sarah about studying slime molds in an ethical way. I told her I felt a little weird about the idea of having a pet slime mold. Does such an intelligent being, able to map the cosmos, really deserve to live in a Tupperware container on a shelf in my house?

“One of the things I really have problems with is people ripping apart logs,” she said. “If you’re doing that, you’re changing the microclimate for all the invertebrates that live under the log. That’s a real problem.”

For deeper kinship, Sarah encourages anyone with a keen interest to use the citizen science app iNaturalist and help broaden our collective knowledge of biodiversity. Because the group of people who study slime molds is small, anyone who keeps a record of encounters can make a meaningful contribution. The more we know about slime molds, the better they can be protected.

She also mentioned how perfect slime molds are for children to engage with, which I soon discovered to be true.

“Mum! Mum! I think I’ve found a slime mold!”

“No. NO??!!!” I shouted, sticking my feet halfway into my trainers and rushing out to my six-year-old daughter in our garden. She was crouching down on the path by our raised beds. It was October but warm and the salvia smelt strongly of black currant. A bumblebee buzzed nearby. Look!

She pointed out a mass of tiny maroon tubes, clumped together on old damp pallets. The wood was loose, so I picked it up and fetched my hand lens. It was a mother-fucking slime mold. In my garden. In my garden! Holy shit. The hunt was really on.

We started to search. A chocolate-colored Stemonitis on a log. A number of cream globules on another. In the woods near us, we started to become more fluent. Our daughter developed a particularly good eye, being so close to the ground. Among the bird’s nest fungus and witch’s butter, we saw spumes of white slime, dotted earths, crackled pins. Berets here. Buttons there. They had always been there, and now we were too. The world is filled with slime molds.

And the craziest thing hadn’t even happened yet.

The acorns had all fallen the day I returned to Burnham Beeches to meet Barry, Gill, and hopefully some more slimes. The late autumn sunlight was gentle and warm, belying the chaos these unseasonal temperatures were beginning to unleash on our planet.

For the fifth or sixth time that month, it was so hot I had to strip off my normal November jumper and coat. The hollyhocks in our garden were re-flowering, and so were the lilacs. Leaves brightened the roads like fireworks, but people outside wore T-shirts.

On the radio that morning, the latest prime minister had decided he would in fact attend the latest major climate crisis summit. “Investment zones” in which habitat can be newly destroyed were still under discussion. Soup had been thrown over a famous painting in protest over the UK government’s refusal to stop using fossil fuels.

Shortly after we met, Barry picked up a leaf which was dotted with tiny “flat cap” slime mold. We stopped at the side of the path, under birch, and time melted as we found leaf after leaf, twig after twig, studded with jaw-dropping structures. A little further up, he directed us to a large log, which turned out to be a hotspot. Gill told me wondrous facts about how saffrondrop bonnet fungi leak bright saffron if touched; how raindrops pop the “eggs” out of bird’s nest fungi; how magpie inkcap ink was used to sign the Magna Carta—at least, according to folklore. We nosed around, stunned and awed, wondering why no one else was here. The wood glowed golden, orange, yellow with the dominant beech trees. It was too warm, too beautiful. We found clumps of eyelash fungus, and hundreds of fruiting bodies of Arcyria slime molds: golden, purple, and maroon. The one “dead” tree was a feast of sacred geometry, a banquet of substrate and life.

In the woods, everything is alive, everything is animate.

Later, at home, I looked at a small piece of wood from the garden under my microscope. The wood was crawling with life. One mite flomped around yellow strings of plasmodium. A springtail appeared, like a miniature midnight-blue wood louse, horned and cute. A clear glass eel wriggled around black hairs. There was so much frass.

A number of the golden fruiting bodies were bursting. Half an hour later the bodies had erupted and changed shape. They had new curly barnets. I looked closer at another section, this time of Arcyria. The ostiole—the opening through which spores are dispersed—resembled a dilating cervix.

Back to the golden beauties. I realized they were moving. Softly sporulating. Filaments waved like seaweed or tentacles, releasing fine gold dust into the air.

A mite with floppy antennae that looked like a rabbit trotted around the stalks, nibbling. I felt voyeuristic, privy to my own personal nature documentary.

There was a drop-of-molasses mite, an armored crab mite, a mite made out of ultrasound gel.

I had not thought mites could be so pretty.

I will tread more carefully from now on. I know a little of how many are on the forest floor.

And then—well, I found my burning bush.

I was sure there must be tons of slime mold in the cemetery next to my house, a peaceful haven in this town. I’d asked the council over the summer if they could leave a pile of dead wood for insects after a tree came down, and I had a feeling it might be a good place to look. It’s in a shadowy part of the cemetery, underneath thick and old yew trees, surrounded by gravestones from the nineteenth century.

I walk there and find the underside of a log of a pine tree glistening—yes! Woah!—a thick slick of bright yellow plasmodium.

Let me make myself clearer about how remarkable plasmodium is. Plasmodium has no brain or nervous system, yet it can perform brain-like, intelligent functions. It knows itself. It is able to learn and anticipate. It can learn, for example, to avoid something potentially harmful. It makes decisions.

I track it day after day. Some of it blobs into globs that hang down and form bright yellow balls which turn blue-gray with iridescence. I can identify it after this happens: it is Badhamia utricularis. The rest of the plasmodium stretches to almost a meter and moves and moves and

I lie down in the cemetery next to the plasmodium and try to listen to it, to contemplate it. I hear the sound of the cars and buses on the road, the gulls above, magpies, machinery, a dog barking, the roar of trains. What is it thinking? I take a note of where it is and notice that twenty minutes later it has moved the length of a grain of rice. I’m awed by its locomotion. A yellow slime moving around next to me. Sharing the same air as me. The same home. The same placenta.

I return again the next day, and I can’t stop staring at its fractal shape. The way its yellow branches so directly and intentionally. Neural rivers of xanthic goo. Just like the veins of our bodies, and the vessels of our eyes, and the branches of the trees, and the clouds above, and the dendrites of galaxies. Blebs pack together, river networks of slime fan and spread. Slugs, worms, springtails, and spiders attend. It abides. And
Veins wiggle and branch like my
Veins wiggle and branch and the trees’
Veins wiggle and branch above.

The fractal shapes in slime molds dissolve the binaries and boundaries collapse.

I feel the slime mold in me.

I wonder if people love the fruiting bodies because they are strangely familiar looking. The hairs of the Trichia look like man-made fibers on a teddy bear. Many resemble human-made confectionery. Others look like they’ve got bombastic hairstyles. Maybe we are not so different.

Perhaps we like them because they are always in a crew. Friendly. On a slime mold group online, we discuss collective nouns. A glitter ball of slime molds, someone suggests. An orgy, a ghostbuster, an overthrow, a slitheration, a slimmering. I suggest a galaxy or a shebang or a sweetshop.

Slime molds have things to teach us. That a being can change but at the same time remain itselves—to use Octavia Butler’s phrase. That there is life and beauty in rot, in decay, in decomposition, in the ashes. That a hallmark of life is evanescence and ephemerality. That our limited, Romantic understanding of the world—“ew, slime”—is outdated. That nonhierarchical, nonbinary being is part of the reality of the world.

It is hard, sometimes, to love slime molds. They are fleeting and fugacious. There one day; gone the next. They make us face the facts: that nothing lasts forever. That ultimate human control is illusory. That we might be at the top by force, but we are not at the center. But I think this is why we need to know them. Our rational, materialistic worldview obscures transcendence and awe. Our culture of forgetting, rejecting, ignoring the wider world requires some work, some assistance, to undo.

How do we see the world as sacred again? By radical noticing. Looking for awe in all of life. Following the wonder in our bodies electric. Before we find new stories, don’t we need to sit and remember? How to venerate the world?

More and more, I think a solution is awe. As Dacher Keltner’s work shows, awe seems to orient us to things outside of our individual selves. It suggests our true nature is collective. Studying narratives of awe in cultures across the world, Keltner and colleagues found that a common part of natural awe is the sense that plants and animals are conscious and aware.

I try and listen again. Perhaps slime molds just want to go about their damn business. How? On dead wood, debris, twigs, leaves, all the stuff we tidy away judiciously and ignorantly, not realizing that we are destroying exquisite jewels.

As our systems fail and break down, what will map our exodus? Slime molds invite us to look with wonder at what is small and overlooked. Perhaps they can help dismantle our delusions of human exceptionalism—with their absurd hidden ethereal beauty. They can dissolve the boundaries we pretend exist—with their remarkable metamorphoses. They can challenge our stagnant cultural notions—with their existence as both collective and individual. They can humble us—with their complexity which is beyond our understanding. We think we have mastered the natural world, yet we don’t know how a slime without an apparent brain can conduct itself intelligently. We think we can bend the Earth to our will, but we know barely anything about microorganisms. We think we are in charge, yet we know next to nothing about the slime around us that reigned on Earth for a billion or more years.

The cemetery slime mold slicks onto a twig, so I take it home and feed it. It grows and it grows and it pulses and it flows and there is the sublime. Now, I see that slime molds are everywhere. Give me a garden, or a woodland, and I will show you.

Can slime molds be symbols of hope, too? I think so. They tell us that our ways of being can be different, that we have little idea of the possibilities of life on Earth, that the boxes and straitjackets society puts people into can be busted open, and that new stories and old stories can take us somewhere kinder, fairer, wiser, one pulse at a time.