Zoë Schlanger is a journalist and staff writer for The Atlantic. The excerpt below is from her new book The Light Eaters: How the Unseen World of Plant Intelligence Offers a New Understanding of Life on Earth.
Azolla filiculoides, or just azolla for short, is one of the world’s smallest ferns, and has grown in wet places for millennia. As is generally the rule with plants, it is unwise to mistake size for complexity. Roughly 50 million years ago, when the Earth was a much warmer place, azolla began growing over the Arctic Ocean in vast fern blankets. For the next million years they absorbed so much CO₂ that paleobotanists believe they played a crucial role in cooling the planet, and some researchers are looking into whether they could help do that again.
The azolla performs another miraculous trick still; some 100 million years ago, it evolved a specialized pocket in its body to house a packet of cyanobacterium that fixes nitrogen. The air around us is nearly 80 per cent nitrogen, and every life form, including ours, needs it to manufacture nucleic acids, the building blocks of all life. But in its atmospheric form, it’s entirely out of our reach. Nitrogen, nitrogen everywhere, and not a single molecule that we can use. In a humbling twist, plants rely wholly upon bacteria that know how to recombine nitrogen into forms the plant – and all of us who get our nitrogen from plants – can use. And so azolla morphed itself into a hotel for this bacterium. The tiny fern feeds the cyanobacteria the sugars it needs, and the cyanobacteria busy themselves with transforming nitrogen. Farmers in China and Vietnam took note of this and have been grinding azolla into their rice paddies for centuries.
I sought out fern guidebooks and fern lore. I was charmed by my own rapaciousness, which had been activated like this only a few times in my life. I was so enamoured that I got the tiny azolla tattooed on my left arm. Journalists are notorious generalists, interested briefly and drenchingly in many things they soon leave behind. But this was, I thought, what it must be like to be taken with something. I had questions, suddenly, about this commonest group of plants that had sprouted seemingly without fanfare. They changed the world. What else did I not know?
As part of this inquiry I bought and devoured Oaxaca Journal, a slender volume of naturalist Oliver Sacks’s observations from a fern expedition to southwestern Mexico he took with a bus full of dedicated amateur pteridologists, all of them from the New York chapter of the American Fern Society. The expedition was co-led by Robbin C. Moran, a 44-year-old curator of ferns at the New York Botanical Garden, who brought them all around the state of Oaxaca. At one point, after days of visiting villages and landscapes, marvelling at produce in the markets and dye vats of red cochineal, and of course all manner of liverworts and ferns, Mr. Sacks has a moment that can only be described as rapture. The afternoon sun is falling strong and slant against high stalks of corn. An older gentleman, a botanist and specialist on Oaxacan agriculture, is standing beside the corn. Mr. Sacks acknowledges the numinous moment – the briefest flicker – with barely half a sentence, but it stung me immediately as true.
“… The tall corn, the strong sun, the old man, become one. This is one of those moments, indescribable, when there is a sense of intense reality, an almost preternatural reality – and then we are descending the trail to the gate, reboarding the bus, all in a sort of trance or daze, as if we had had a sudden vision of the sacred, but were now back in the secular, everyday world.”
The experience of flashes of the eternal, the real, the gestalt, runs like a thread throughout naturalist literature. I wasn’t the only one who had been taken like this before. In Pilgrim at Tinker Creek, the writer Annie Dillard has a similar moment in front of a tree, watching light pour through its branches. A flash of the real. Almost as soon as she realizes she is having it, it is gone, but it leaves her with the awareness of a sort of open-plan attentiveness that can be accessed in snippets, and which might be a more direct observation of the world than the usual everyday version.
As I read more books about plants and their enraptured naturalists after work and into the early morning, I began to find these moments sprinkled everywhere. In The Invention of Nature, Andrea Wulf‘s biography of the famous 19th-century naturalist Alexander von Humboldt, I learned he’d had it too. Von Humboldt wondered aloud why being in the outdoors evoked something existential and true. “Nature everywhere speaks to man in a voice that is familiar to his soul,” he wrote; “Everything is interaction and reciprocal,” and therefore nature “gives the impression of the whole.” Von Humboldt went on to introduce the European intellectual world to the concept of the planet as a living whole, with climatic systems and interlocking biological and geological patterns bound up as a “net-like, intricate fabric.” This was Western science’s earliest glimmer of ecological thinking, where the natural world became a series of biotic communities, each acting upon the others.
Something about reading botany papers gave me snatches of that feeling, glimpses of a sort of whole I couldn’t yet fully articulate. I had the sense I was uncovering large gulfs in my knowledge. How long had I spent in the presence of plants while knowing next to nothing about them? I felt a curtain drawing back little by little onto a parallel universe. I knew it was there now, but not yet what it held.
Copyright 2024 by Zoë Schlanger. Reprinted by permission of Harper, an imprint of HarperCollins Publishers.