Imagine stumbling upon a 400-million-year-old secret handshake between plants and fungi that literally paved the way for life to conquer the land – a partnership so pivotal it could redefine how we view evolution! But here's where it gets controversial: Was this alliance born out of necessity, or could it have been a cunning strategy that fungi used to dominate early ecosystems? Dive in with me as we explore a groundbreaking fossil discovery that rewrites our understanding of one of Earth's oldest collaborations.
Ancient Fossil Unearths the Dawn of Plant-Fungus Bonds | Natural History Museum
Science Updates
By James Ashworth
Originally Posted on November 12, 2025
For eons, plants and fungi have coexisted in a dance that's sometimes cooperative and at other times adversarial, much like an intricate partnership in a survival game.
A recently unearthed fungal fossil from Scotland illuminates the earliest clues of their intertwined story, showing how these organisms exchanged vital nutrients to thrive in terrestrial environments.
Preserved within a minuscule formation that's been locked in time for over 400 million years, this find provides tantalizing insights into what might be the most enduring alliance in the chronicle of life on our planet.
Life on Earth was confined to aquatic realms for billions of years. It wasn't until about 500 million years ago that plants began venturing onto dry land, as detailed in studies like one from BMC Evolutionary Biology (https://bmcecolevol.biomedcentral.com/articles/10.1186/1471-2148-11-104). Yet, the precise mechanics of this groundbreaking shift have long puzzled scientists.
Fresh investigations, featured in the publication New Phytologist, bolster the case that fungi played a crucial supporting role.
Traces of their mutualistic connection, termed mycorrhiza – a term you might think of as a 'fungus-root' friendship where both parties benefit – were spotted in a 407-million-year-old specimen from Scotland's Windyfield Chert. Nestled within the fossilized remains of an ancient plant lay a delicate feature called an arbuscule, which facilitates the swapping of nutrients between plants and fungi.
The researchers christened this fungus a new species, Rugosomyces lavoisieriae, paying tribute to Marie-Anne Paulze de Lavoisier (https://link.springer.com/article/10.1007/s00897980249a), a trailblazing French figure who advanced physiology and chemistry in the 18th century. Our lead scientist, Dr. Christine Strullu-Derrien, spearheaded this research.
'Mycorrhizas are exceedingly uncommon in the fossil record and haven't been documented in the Windyfield Chert until now,' Christine notes. 'The arbuscule's presence indicates the fungus wasn't acting as a parasite or scavenging after the plant's demise – rather, it points to a beneficial symbiosis.'
'In this setup, the fungus supplied essential minerals, such as phosphorus, in exchange for sugars from the plant, creating a win-win scenario for both.'
Dr. Paul Kenrick (https://www.nhm.ac.uk/our-science/people/paul-kenrick.html), a specialist in fossil plants at our institution and a contributor to the study, describes it as 'astonishing' to uncover such primordial proof of a symbiotic bond.
'Dry terrestrial habitats posed immense hurdles for plants,' Paul elaborates. 'Around 400 million years back, most lacked true roots, complicating nutrient absorption.'
'It seems these symbiotic ties were essential for plants to acclimate to land life. With mycorrhizas present in more than 85% of modern plants (https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.15076), unraveling their origins could enrich our grasp of evolutionary history, current ecosystems, and even future adaptations – think of how understanding these partnerships might inspire sustainable agriculture today.'
And this is the part most people miss: These ancient alliances aren't just relics; they mirror modern-day examples, like how certain crops thrive better with fungal helpers, boosting yields in organic farming. But what if fungi were the true pioneers, manipulating plants for their own gain? It's a provocative angle that challenges our view of 'mutualism' – what do you think?
Exploring the Windyfield Chert
The Windyfield Chert represents a sedimentary rock formation in the Scottish Highlands, tracing back to the Early Devonian era. It's roughly contemporary with the famed Rhynie Chert, located in close proximity.
Both cherts are celebrated globally for their meticulous preservation of a prehistoric wetland habitat. Picture scenes akin to today's Yellowstone National Park in the USA, complete with sandy soils, thermal springs, and watery pools.
This ecosystem met a sudden end approximately 407 million years ago when silica-laden waters from geysers surged into the marshland, encasing the inhabitants in a fossilized time capsule. This natural event has gifted researchers an abundance of exquisitely maintained specimens from a critical evolutionary juncture.
Traditionally, chert samples are sliced into translucent sections for examination under light microscopes, reconstructing the ancient landscape. While effective for studying larger plant structures, standard microscopes falter with minute fungal elements. So, the team extracted a fresh sample from the Windyfield Chert and subjected it to laser illumination.
'Conventional light microscopy delivers detailed views, but confocal laser scanning microscopy elevates it significantly,' Paul explains. 'By employing lasers to induce fluorescence and filtering out blurry light, we achieve sharper, more precise images.'
'Collaborating with experts at Cambridge's Sainsbury Laboratory, we advanced further using fluorescence lifetime imaging microscopy, or FLIM. This technique gauges the decay time of fluorescence to deduce the chemical makeup of various fossil components.'
Unpacking an Age-Old Symbiosis
This research marks the inaugural application of combined confocal microscopy and FLIM on fossils, unveiling their intricacies with unmatched clarity.
From the enhanced visuals, scientists identified Rugosomyces lavoisieriae intertwined with Aglaophyton majus, an early plant. In contemporary species, mycorrhizas typically inhabit roots, but Aglaophyton lacked them.
'Roots were scarce among plants then,' Christine points out. 'They relied on thread-like appendages known as rhizoids. Thus, although mycorrhiza means 'fungus root,' we detected it in aerial plant sections.'
'Nowadays, such configurations appear only in select liverworts and hornworts. We must investigate why this arrangement evolved.'
Delving deeper into this phenomenon could illuminate the symbiosis's initial development. For instance, did it originate underwater, or emerge post-land migration? Research on freshwater green algae – the closest living kin to plants – reveals partial genetic readiness for symbiosis, hinting that land-dwelling ancestors added the missing pieces. Yet, this remains unresolved.
A quandary that's sure to spark debate: How did plants and fungi navigate coexistence without conflict? Normally, a fungal intrusion triggers a plant's defenses, erecting chemical walls, but symbiotic fungi suppress these reactions. The team speculates that remnants of these barriers might linger in Rhynie and Windyfield Chert fossils, shedding light on mycorrhiza's rise to ubiquity.
'No one's examined immune responses in fossils this old,' Paul says. 'But traces could persist, even after 400 million years.'
'It would be groundbreaking to detect them, granting unparalleled perspectives on the joint evolution of plants and fungi.'
As we wrap up, ponder this: If fungi helped plants colonize land, does that make them unsung heroes or opportunistic invaders? Could studying these ancient bonds help us combat modern environmental challenges, like soil degradation? Share your thoughts in the comments – do you agree this symbiosis was purely beneficial, or is there a darker side to their story that we've overlooked?
