Agarikon is one of two endangered species of fungi in the United States. So rare is the species that scientists have placed samples of it in a biobank facility for safekeeping at the San Diego Zoo, in the hopes that it can be propagated and one day reintroduced to the wild should its numbers continue to decline.
Agarikon, also known as quinine conk, is a large round or semicircular shelf fungus that grows on the bark of old growth conifers in forests around the world. Two thousand years ago a Greek physician called agarikon “an elixir of long life.” For centuries it has been used to treat tuberculosis, rheumatism, asthma, cancer, and inflammation, among other maladies.
Research confirms the fungus has robust healing properties: It contains powerful antimicrobial, antiviral, and anti-cancer compounds. It has also recently been found to potentially reduce side effects of the Covid-19 vaccine and enhance immunity.
Yet the species’ future is in doubt.
“In the past hundred years it declined 70 percent, and we don’t have evidence that decline is stopping,” said Jessica Allen, lead mycologist with NatureServe, a Virginia-based nonprofit concerned with biodiversity protection. “The Pacific Northwest is the last stronghold.”
There are as many as 12 million species of fungi, yet there are just 155,000 or so known species, leaving vast numbers undescribed.
The reason that only two fungi species in the U.S. are classified by the International Union for Conservation of Nature as endangered is not because other fungi populations are healthy, but because knowledge of the world’s mushrooms, mildews, lichens, mycorrhiza, and other fungi is extremely scant. Still, researchers know enough about their ecological functions to understand they are indispensable to most plant life. As many as 90 percent of plants use their roots to form symbiotic relationships with vast webs of mycorrhizal fungi to, among other things, increase their nutrient and water absorption by orders of magnitude beyond what soil alone can provide.
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“Without this fungal web my tree would not exist,” wrote mycologist Merlin Sheldrake in his best-selling 2020 book Entangled Life. “Without similar fungal webs no plant would exist anywhere. All life on land, including my own, depended on these networks.”
It’s estimated that there are, on the low end, 2.2 million species and on the high end up to 12 million species of fungi in the world. Yet there are just 155,000 or so known species, leaving vast numbers undiscovered and undescribed.
The lack of knowledge about the world’s fungal kingdom, in spite of its essential role in maintaining life, has led to a campaign to elevate the importance of fungi to the same level as flora and fauna. Increased recognition, advocates say, would lead to greater inclusion of fungi in research, policy, and preservation considerations. Just 10 percent of the world’s mycorrhizal hotspots, for example, occur in protected areas.
An agarikon mushroom in Oregon.
Adam Bryant via iNaturalist
The protection “is needed. It’s important,” said Allen. “Fungi play an important role in the ecosystem. We know a lot about fungi, but mycologists haven’t been invited to the table to share their knowledge.”
Fungi are getting a good deal more attention in some quarters these days as scientists learn more about — and publicize — their role. In Entangled Life, Sheldrake explained the many facets of fungi, from their role in ecosystems to how they have shaped human culture and their unusual intelligence. Earlier this year the Tyler Prize for Environmental Achievement, known as the “green Nobel Prize,” was awarded to Toby Kiers, an evolutionary biologist at Vrije University Amsterdam, for her work studying how plants, soil, and microbes are connected by mycorrhizal networks and how they draw carbon from plant roots in exchange for nutrients. She also shared a MacArthur Foundation “genius grant” in 2025 with Giuliana Furci, a mycologist in Chile who also heads the New York-based Fungi Foundation. “The awards feel like an award for the invisible,” Kiers told The New York Times, “and a celebration of decentralized ways of thinking and operating that fungi have mastered.”
Still, much of what fungi do remains a mystery. “The whole concept of understanding functional roles in fungi is complicated because of their hidden nature,” said Andrew Wilson, associate curator of mycology at the Denver Botanic Gardens, who works to document fungal diversity and is part of the effort to raise its profile. “They are very cryptic. A plant is aboveground, and you can see the differences between them. Mushrooms are underground or live within the tissues of other organisms, and what they are doing is hard to study.”
“Every organism has a fungal component that is sustaining them,” says a mycologist. “They are the firmament of life on Earth.”
Those who study and promote awareness of the world’s fungi are often evangelical in their approach. Appreciating and studying fungi, says Furci, will change how you see the world. “Every organism has a fungal component that is sustaining them,” she said in an interview. “They are the firmament of life on Earth.”
Endophytic fungi, for example, live between and also within the cells of virtually all vascular plants. They are critical for plant growth, resilience, and survival. They emit molecules — natural antibiotics — that protect the plants against disease. They help repel herbivores and insects. They also enhance the uptake of phosphorus, nitrogen, and other nutrients; improve water retention; and help plants tolerate stress. Scientists are studying these fungi to accelerate the discovery of other compounds, from medicines to diesel fuel.
Fungi are vital to an incredibly wide number of products and services, including drugs like penicillin, ampicillin, statins, and antifungals, nutraceuticals, fermented foods, cheese, beer, wine, spirits, colorants, cosmetics, and fertilizers. A recent paper pegged the value of all types of fungi at nearly $55 trillion, a figure that includes the value of sequestered carbon traded on global markets.
Mycologist Toby Kiers.
John D. and Catherine T. MacArthur Foundation
Mycologists refer to fungi as ecosystem engineers because they perform essential roles. Approximately 80 percent of terrestrial plant species partner with fungi, according to a number of studies. Ectomycorrizal fungi, for example, form a dense, protective sheath around the root tips of trees, including oaks, beeches, and pines. It’s a symbiotic relationship: The fungus provides the tree with nutrients, such as phosphorus and nitrogen, from the soil, in exchange for carbohydrates produced by the trees through photosynthesis. Fungi increase the surface area of trees’ root systems, allowing them to live in nutrient-poor or even toxic conditions.
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Research increasingly shows that as ecosystems are restored with native plants, creating conditions that enhance the growth of native fungi with the plants’ roots enhances their vigor and survival.
One species of mycorrhiza that has been well researched is in the genus Suillus, which grows on the roots of pine trees. “They can differentiate in their tissues between the toxic metals”— whether naturally occurring in soil or deposited through human activity — “and the nutrients that the trees need,” said Wilson, “and preferentially feed the tree nutrients while preventing these toxic metals from harming the trees.”
Researchers estimate mycorrhiza sequester 13 billion tons of carbon in soil annually, roughly a third of the world’s fossil fuel emissions.
That is just one known function of one species, said Wilson. “Biologically they are not all doing the same thing. If they were, there would not be a need of all this [fungal] diversity.” That could mean there are myriad other roles that mychorrizae play in their symbiotic relationship with plants.
Fungi began breaking down rocks and recycling nutrients more than 900 million years ago to form the first primitive soils. “They were a key innovation that allowed plants to move from the ocean onto the land,” said Allen. Today they continue that function, breaking down dead trees and other vegetation, making nitrogen, carbon, and other nutrients available for new plant growth and building robust soil ecosystems.
Fungi are also major players in carbon sequestration. Soils hold 75 percent of terrestrial carbon and about 59 percent of the planet’s biodiversity. Kiers and her colleagues estimate that mycorrhiza sequester 13 billion tons of carbon dioxide in soil annually, the equivalent of a third of the world’s fossil fuel emissions.
As critical as they are, though, fungi are not often on the radar for protection. They face a range of familiar threats, from climate warming, which reduces diversity of fungi, to land development. A recent study of highly diverse mycorrhizal global hotspots, conducted by the Society for the Protection of Underground Networks (SPUN), found that just 10 percent of these rich mycorrhizal ecosystems occur in protected areas.
A mycorrhizal fungus growing around the roots of a white spruce.
André-Ph. D. Picard via Wikipedia
SPUN was founded by Kiers and others in 2021 to map mycorrhizal networks using DNA sequencing and machine learning. The group has mapped key areas of fungal biodiversity — which generally have ample moisture, are undisturbed, and have complex plant communities — and advocates for their protection.
Kiers and her colleagues also set up the Underground Explorers Program, a network of scientists around the world who are mapping fungal diversity in their regions before species blink out. And they recently launched a project called Underground Advocates to train mycologists in legal and policy skills, with the aim of campaigning to raise the profile of what they call the Kingdom of Funga.
Other efforts are underway. The Fungi Diversity Initiative, or FUNDIS, began in 2012 but has picked up steam in recent years. Its citizen scientists are contributing to a global fungal database while a team of experts is sequencing fungi genomes and identifying species of concern.
California has one of the most advanced efforts to collect, catalog, and census fungi. Since 2022 the California Fungal Diversity Survey has gathered more than 10,000 different fungi species in the state and sequenced their DNA. More than 2,000 of those are new to science.
At the U.N. biodiversity conference in 2024, 13 countries informally agreed to recognize fungi on a par with flora and fauna.
Existing collections of fungi — such as the Fungarium at Kew Gardens in London, which houses more than 1.25 million specimens — are also being examined with new technologies.
In 2024, at the COP16 Biodiversity Conference, the governments of Chile and the U.K. introduced the Fungal Conservation Pledge, in which countries would agree to recognize fungi on the same level with flora and fauna. Thirteen countries informally agreed, and the plan is to introduce the agreement at COP17, in the fall of 2026, for formal adoption.
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The goal, said Maisa Rojas Corradi, Chile’s minister for the environment, is “to integrate fungi into global conservation strategies and frameworks, highlighting the key role they play in the fight against climate change, biodiversity loss, and the promotion of sustainable economic development.”
Fungi advocates are encouraged by all that has happened in the last few years and confident that fungi are starting to get their due. “The shroom boom is definitely happening,” said Gabriela D’Elia, former director of the Fungal Diversity Initiative. “It’s a fungal awakening.”
