I love the idea that something growing beneath a fallen log might be carrying a trace of where it's been. Fungi already have an unfair advantage when it comes to being interesting. They can produce beautiful mushrooms, dismantle dead wood and spend much of their lives in a form most of us barely notice. Give me a claim about fungal memory and, naturally, I'm going to keep reading.
What caught my attention was the possibility that earlier conditions can change how a fungus grows later. Researchers have actually tested versions of that idea, moving colonized wood into fresh soil and watching which direction new growth takes. That is wonderfully strange all by itself. It also raises a question I like considerably more than the idea of a mushroom recognizing me personally: how much history can a living body carry in its structure and chemistry?
The Mushroom Is Only the Part We Usually Notice
A mushroom is a reproductive structure produced by certain fungi. Much of the organism can exist as fine filaments called hyphae, which collectively form a mycelium. Kew explains the distinction and why fungi belong to their own kingdom. Their way of getting food involves releasing digestive substances into their surroundings and absorbing the resulting nutrients. Dinner happens outside first, which is a rather different arrangement from putting a mushroom in a pan.
The filaments can spread through soil, wood and other material, forming a body with many growing tips. That's the part involved in much of the research discussed here. As a gardener, I find it particularly satisfying that a patch of apparently ordinary material can contain so much activity. I can be preoccupied with whether the tomatoes are behaving themselves while an entirely different set of organisms is getting on with its own complicated life nearby.
The Experiment That Tested a Trace of Earlier Growth
In a study by Yu Fukasawa, Melanie Savoury and Lynne Boddy, the wood-decaying fungus Phanerochaete velutina grew from an already colonized piece of wood toward a new wood resource. After it connected with that resource, researchers moved the original wood into fresh soil, breaking the external connection. When growth resumed, it was greater on the side that had previously faced the new resource. Earlier growth appeared to leave a directional influence that persisted through the move.
The result was described as ecological memory. The exact internal basis remained unresolved, and the experiment concerned a particular fungus in a controlled setup. I keep thinking about the change of setting: the old external route was gone, but the next growth was still influenced by what had happened before. You can understand why a researcher would want to follow that result into another experiment. I certainly wanted to know what changed the response.
How Long the Fungus Waited Mattered Too
A 2021 study by Fukasawa and Koji Kaga examined how the timing of a new wood resource affected fungal growth and migration. They offered it either relatively early or after a much longer wait. Following colonization, they moved the old and new wood pieces separately to fresh soil and tested whether growth resumed. In two species, the longer wait was associated with cases in which only the new resource produced regrowth.
The authors suggested that depleted resources could help explain the difference. That's a useful complication because elapsed time and the condition of the food source can change together. I like that the experiment starts with something so ordinary: when dinner becomes available. The longer you think about the practical problems a fungus faces, the easier it is to see why its previous conditions might matter to what happens next.
Another Fungus Gave Researchers a Different Result
A 2025 experiment with Laccaria bicolor tested whether exposure to a nutrient source left a similar directional effect. Researchers offered pea cotyledons, then transferred part of the mycelium to fresh medium and looked for unequal growth toward the nutrient's former position. They found no evidence of memory under those conditions. Species, experimental design and what gets transferred all become part of the question.
I appreciate that result being available alongside the more eye-catching ones. It makes the whole subject feel considerably more interesting than a declaration that every mushroom remembers everything. You've got different organisms, different ways of growing and a question that needs testing each time. The difficult part is figuring out what the test is actually measuring, especially when the organism's growing body is also the thing being studied.
The Arrangement of the Food Can Change the Network
In research reported by Tohoku University in 2024, colonized wood blocks were placed in circle and cross arrangements. Over 116 days, P. velutina developed networks whose connections differed with the layout, and the amount of wood decay was associated with how connected the blocks were. The authors raised the possibility of a form of pattern recognition. What they measured was network organization and decay in response to the resources' spatial arrangement.
I find the timescale worth sitting with for a moment. We can glance at a circle or cross and identify it immediately, while this experiment followed a growing organism over months. The fungus's relationship with the arrangement unfolded through the body it built and the material it consumed. I like trying to follow that process in my head, although my brain keeps wanting to turn it into a much faster little movie.
A Changing Network Has to Balance Several Jobs
Growing farther takes material, and maintaining connections takes resources too. In a study of fungal transport networks, researchers photographed P. velutina as it developed on soil and analyzed the changing architecture. Selected connections became reinforced while other material was withdrawn. Their network analysis found combinations of transport capacity and robustness to damage that improved as the network developed.
That helps me understand the fascination with decentralized growth. A fungus can alter a network without a central office approving every extension, but it still has physical limits and costs. I'd be interested in that arrangement even if the only question were how it reaches another piece of wood. Add the effects of earlier growth, resource timing and location, and a supposedly simple organism starts giving us a fairly substantial collection of problems to think about.
Yeast Gives Us a Different Example of Cellular Memory
Yeast belongs to the fungal kingdom too, which gives my wine-interested brain an excuse for a small detour. In a 2012 study of Saccharomyces cerevisiae, mild salt exposure helped cells tolerate a later hydrogen-peroxide challenge. That acquired resistance persisted through several cell divisions. A long-lived protective enzyme, made during the earlier treatment and passed into daughter cells, helped explain one part of the effect.
Here, memory had a concrete biochemical basis researchers could investigate. The cells also showed a faster gene-expression response after another treatment, a separate aspect of the response. This was a laboratory study of yeast, so its mechanism needs to stay attached to that organism and experiment. Still, I like having something as tangible as a persistent protein to think about when a word as familiar as memory turns up in an unfamiliar setting.
The Famous Maze Solver Is a Slime Mold
One of the best-known maze stories involves Physarum polycephalum reorganizing its network between food sources. It is a slime mold, an amoebozoan, which places it outside the fungal kingdom despite the misleading name. Its spreading body can look enough like a fungal network that the stories are easy to mix together. I think it deserves its own credit for the work, especially when a yellow, many-nucleated cell has become so famous for its arrangements.
Researchers have also reported habituation in Physarum: repeated exposure changed its response to substances such as quinine or caffeine, and the response returned after a break. That's an interesting form of learning to investigate in an organism without neurons. The important distinction here is which organism performed which task. I can apparently accomodate a great many strange creatures in one mental category, but the experiments make much more sense when I keep their names straight.
Electrical Activity Gives Us More Questions to Follow
Electrical measurements have added another layer to the subject. Andrew Adamatzky's 2022 paper grouped recorded fungal voltage spikes into patterns and compared their lengths with words. That was a proposed interpretation of the recordings. It did not establish a translated vocabulary or show that a mushroom was composing sentences about whoever happened to pass it.
A 2025 review of fungal electrical signaling discusses how difficult the measurements can be, including separating biological activity from background effects and choosing equipment suited to slow signals. Then a 2026 oyster-fungus study reported delays between electrode channels consistent with slow traveling activity. The research is continuing, with the nature and significance of the signals still requiring careful work. A voltage trace gives us a starting point for questions about a mechanism, rather than a direct readout of a thought.
I understand why the language comparison catches on. A network, an electrical trace and a few familiar words make it very easy to start filling in a conversation. What holds my interest longer is the possibility of finding out what a signal actually does within the fungus. I would love to know how one part of a growing body affects another, especially when that body is spread through something we ordinarily think of as a lump of wood.
An Underground Partnership Is Already Remarkable
The familiar wood-wide-web idea comes from a different set of fungal relationships. Mycorrhizal fungi can associate with plant roots, receiving carbon-containing compounds from plants while helping them obtain nutrients and water. A shared fungal partner can link multiple roots. The wood-decomposing fungi in several of the growth experiments above have a different ecological role, so it helps to keep those relationships distinct.
How much a shared network does in a natural forest is a much harder question. In a 2023 examination of common mycorrhizal-network research, Justine Karst and colleagues found that popular claims often exceeded the evidence. They highlighted variable field results, alternative explanations for resource movement and unsupported assertions about mature trees preferentially helping their own seedlings. The relationships are real, while the broad story about an entire forest deliberately looking after itself needs stronger evidence.
This is where I find myself thinking about how much I enjoy the story of a forest cooperating. It's an appealing image, particularly when so much of the world feels competitive. Fungi have their own resource needs and relationships, though, and I think we get a richer picture by allowing those relationships to be complicated. A living patch of soil can contain cooperation, competition and changes we haven't figured out how to describe yet.
The Part About Memory That Keeps Me Interested
I can find something moving in the idea that a living body's present shape carries traces of its past. That's a personal response to the image of growth, and I can enjoy it while keeping the experiment itself quite specific. A connection thickened, an earlier condition influenced a later response, or a molecule persisted long enough to change what happened next. Each is a different kind of explanation to follow.
The original question that drew me in still feels wonderfully odd: what can an organism do with the information available to it? We tend to picture a creature moving around, finding food and bringing it back somewhere. A fungus can extend the body itself toward a resource and change that body's organization as conditions change. I keep trying to think through what an ordinary day would even mean for something whose growth takes that form.
A mushroom beside a path gives us a small, visible part of a much larger story. Under the surface, or inside the wood supporting it, there may be growth, digestion, resource movement and a history researchers can test in carefully chosen ways. I'm happy to leave the question of personal recognition with the people and animals who actually recognize me. The fungus has already given me enough to wonder about, and I would very much like to see what the next experiment finds.
Related Reads
Watching Fungal Growth at Home
For anyone interested in watching a cultivated fungus develop, the mushroom-growing kit listing offers one way to bring that interest onto a much smaller scale. Species and growing instructions depend on the particular kit. I like the appeal of having a visible process to follow over time, while the experiments about memory involve their own controlled conditions and comparisons. Watching mushrooms form would give me quite enough to be occupied with before I started assigning the colony a personality.
Sources
Fukasawa, Savoury and Boddy. Ecological memory and relocation decisions. The ISME Journal, 2020.
Fukasawa and Kaga. Resource timing and fungal migration. Journal of Fungi, 2021.
Tohoku University. Spatial arrangement, fungal networks and wood decay. 2024.
Guan and colleagues. Cellular memory of acquired stress resistance in yeast. Genetics, 2012.
Nakagaki, Yamada and Tóth. Maze-solving by an amoeboid organism. Nature, 2000.
