Amanitas, these link-weaving mushrooms

The fly agaric weave links through forest ecosystems, but also between humans and spirits. Francis Martin, Supplied by the author

The fly agarics, very abundant this fall, cause respectful concern in the forest. Like many other fungi, they have a secret life, which humans have long explored for their hallucinogenic properties, and, more recently, for their roles in forest ecosystems. Francis Martin, an expert in symbiotic interactions between fungi and trees, explores in his book published by Salamander editions the bonds that mushrooms weave – between people and spirits, but also with plants. Here is an excerpt.

Impossible to miss this beautiful mushroom. He is recognizable among a thousand with his long white foot surrounded by a ring, his volva and his large flat, red hat, spotted with white warts. This amanita abounds in deciduous and coniferous forests, often in the company of porcini mushrooms. Beautiful and elegant, it has nevertheless become one of the symbols of witchcraft in traditional imagery.

It is true, it contains an abundance of toxic poisons, but even crushed in milk, it does not kill flies. Muscarine, the potentially deadly toxin it contains in small quantities, does not withstand cooking. Its consumption is therefore rarely fatal. On the other hand, it contains high concentrations of psychoactive compounds similar to major neurotransmitters of the central nervous system whose effects they mimic, muscimol and ibotenic acid. These substances disrupt neural transmission in the mammalian brain and thereby stimulate the psyche and cause sensory changes. The unfortunate or voluntary ingestion of the fly agaric leads to hallucinations, then to a drowsiness filled with powerful dreamlike visions.

Due to its hallucinogenic properties, dried amanita was already consumed during worship services dedicated to Dionysus in Greece. Among the Koriaks of Kamchatka, the psychic states provoked by the fly agaric were so appreciated that they engaged in a singular traffic. Dried amanita powder was consumed by the sorcerer and clan nobles during shamanic ceremonies; the urine of these privileged consumers, enriched with active principles, was then drunk by the other members of the tribe. The ethnologists’ report does not tell us whether the number of rabbits in frock coats or Cheshire cats encountered during these hallucinatory journeys varied with the number of passages in the urine. Mushrooms are often feared because they can be deadly or linked to the magical practices I just mentioned.

Moreover, for thousands of years, the sorcerers of the Amerindian tribes have used for religious, spiritual or shamanic purposes plants and mushrooms rich in psychotropic substances inducing a modified state of consciousness. Some puffballs are still used for divinatory purposes because of their hallucinogenic properties by the Mixtec sorcerers of Oaxaca. These mushrooms have an essentially hypnotic effect. They cause a state of half-sleep during which sorcerers claim to perceive the song of the gods. Among the Tarahumaras of northern Mexico, sorcerers absorb the kalmoto, another species of puffball, to approach their victims unseen in order to cast a spell on them. In the shamanism of the Papuans of the high plateaus of New Guinea, we find the use of hallucinogenic mushrooms such as psilocybe or the boletus which drives mad. Indeed, the ingestion of the latter can lead to deadly dementia.

An ancestral alliance with trees

The fly agaric would therefore make it possible to forge links with the spirits – this is a widespread belief among many forest peoples. It is undoubtedly a fascinating subject of study for anthropologists. As a biologist, I have spent a good part of my life studying this forest organism because it is a prince among fungi. He knows how to dialogue with the roots of trees. Invisible under our feet, it weaves its web of underground filaments in the soil and the humus of the forests and in the fall it produces these beautiful fruiting bodies with red caps dotted with white warts. It is even more extraordinary than you could imagine.

Over tens of millions of years of co-evolution, the amanita and its host trees – oak, spruce or birch – have developed a sophisticated partnership. The two organisms – plant and fungus – form a mutualistic symbiosis, an alliance with mutual benefits. In the telluric darkness, they created a “joint venture” to explore, prospect and exploit the resources of the subsoil, the deposits of nitrogen, phosphates and micro-elements, essential to their growth.

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Among the 5 million species of fungi that inhabit our planet, the fly agaric is one of those which, along with some twenty thousand other forest fungi, is capable of dialoguing and cooperating with trees. Indeed, its underground mycelial filaments are associated with the short roots of trees where it forms a mixed, chimerical organ, called “mycorrhiza” (from the Greek múkês, “mushroom”, and rhiza, “root”) – a root-fungus. The presence of the symbiotic fungus on the rootlets of the tree favors the absorption by the roots of the mineral elements of the soil, which considerably improves its nutrition.

Amanitas, but also cortinaires, russules, boletes or truffles, transform the small absorbing roots of the host tree. The mycorrhizal root is then extended by a vast network of mycelial filaments propagating in the soil. If you lift the heap of dead leaves and litter that cover the ground at the foot of the trees, you will be able to observe this whitish felt coating coating the soil particles and plant detritus. The filaments, interconnected and intertwined, project their ramifications into the slightest crevice of the soil, the humus and the litter. They perform an essential exploration and absorption role (up to 1,000 meters of mycelium per meter of root).

The mycorrhizal symbiosis is not only formed from the small root of the tree extended by its immense network of mycelial filaments. During their age-old partnership, root and fungus developed a very complex chimeric organ. Mycelial filaments entangle on the surface of the root, then agglomerate around the small root before completely coating it with a dense sleeve of mycelial felt. Under the microscope, we really have the impression of observing a cottony glove finger on each of the rootlets.

Even more surprising, the microscope allows us to distinguish the mycelial filaments of the amanita insinuating themselves into the space which separates the cells of the epidermis from the root. The tip of the mycelial filaments sinks like a wedge between the large root cells of the host without ever penetrating them. Each cell of the root epidermis ends up being entirely surrounded by the very fine filaments of the fungus – after so many years of studying and observing these mycorrhizal roots, I am still amazed by this image of the large root cell; a large cube of 0.1 millimeters side, coated with its mesh of filaments whose size is ten times smaller.

It is at the level of these mushroom-clad cells that the exchange of nutrients (sugars, amino acids, mineral elements) takes place between the two symbionts. In this fair trade, the mushroom exchanges the mineral elements that it has absorbed from the soil and transported along its network of mycelial filaments for soluble sugars, such as glucose. For both partners, this exchange – this barter – is crucial. Mineral elements, such as nitrogen, phosphate and potassium (the famous NPK mixture of garden center fertilizers), are necessary for the growth and good health of the tree. Glucose, provided by the roots of the plant, is the sugar that allows the fungus to fuel its metabolism, to live, to breathe and to build its underground network of filaments. For him and his host tree, as for us, glucose is the fuel of life.

The original version of this article was été published on The conversation, a news site à dédié to the sharing of ideas between academic experts and the general public.

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Amanitas, these link-weaving mushrooms

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