Nestled within the tarmac lasso around London formed by the M25 motorway but feeling very far in time and space from the city, Charles Darwin’s home, Down House, has a spooky quality: it feels like he just popped out. His office is strewn with correspondence and open books, specimens of insects and fossils; his chair, fitted with castors so he could roll around like a Dalek collecting things, still seems to retain the impression of his body. A wooden slide is propped against a wall: Darwin had made it to fit over the staircase, so the children could slide down on cushions.
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In fact the presence of his children lingers: a mulberry tree growing up the side of the house, gnarled and propped up on stilts, is the same tree the Darwin children would climb down from their bedroom window. There’s a display about poor Annie Darwin, her father’s favorite child, who died aged ten, whose death stripped her father of his last intellectual respect for a Christian god. The gardens are planted with the same flowers Emma grew (she was in charge of the garden) and the kitchen garden still grows the same vegetables that fed the Darwins and their staff.
Antony O’Rourke, the current head gardener, shows me around and encourages me to pick some food. The evening after visiting I eat chard and cavolo nero grown in Emma’s kitchen garden. It’s a pseudo-religious experience. I scraped my boots on the same boot scraper outside the greenhouse that Darwin used. I walked the Sandwalk, the thinking path around the property Darwin would pace every day.
This is the magnificence of orchids: in form their deception, their sexuality, their lust, their behavior is frozen in place.
The path wanders through woodland that didn’t exist in Darwin’s time—because he planted it. People talk about our debt to the future, and the things we should do now for the sake of people not yet born, and walking in mature woods that Darwin created filled me with love and gratitude. I found the spot on the path where he would place a stone, so he could keep count of the number of laps he’d completed (his children would add stones after he’d walked past to trick him). In Darwin’s woods I was moved that I was feeling pleasure from something he initiated but never got to see. And in his woods are some plants he would be fascinated by.
Here and there in the deep shade under the beeches is a species of orchid called violet helleborine (Epipactis purpurata). Antony explains that the orchids time their flowering for when fruits have fallen to the ground and wasps are patrolling for food. Bees avoid the gloom of the understory—with few flowers, there’s little to entice them—but wasps don’t mind it, and are attracted to the helleborines by the promise of an intoxicating nectar (itself made by a symbiosis with fungi). When they drink it, becoming dusted with pollen as they do so, the wasps seem to get drunk. They give up on personal hygiene; they let themselves go. This means they don’t groom themselves with anything like the care they normally would, and pollen remains stuck to them. They stagger to the next flower, like a pub crawl with bonus pollination events. If you examine the orchid flowers, you’ll find a sort of shield stopping the pollen falling from the male parts of the flower onto the female parts, preventing self-pollination.
But the pollen parts are themselves tucked away, meaning the plant can’t rely on wind for pollination. You can predict, therefore, that this must be an insect-pollinated flower. This is the magnificence of orchids: in form their deception, their sexuality, their lust, their behavior is frozen in place. This too is the wonder of trees, how their lives stretch for hundreds of years, fixed in place, experiencing the decades, recording the seasons, capturing their essence; the thousands of seeds produced, rolling with the punches, countless dramas and births and deaths and battles, all taking place in something apparently static, that we walk past and take for granted. And in their relationship with fungi there is more still, underground.
Darwin had long been interested in orchids, possibly influenced by the borderline sexual love his grandfather, Erasmus, felt for them and put into his writings. In The Botanic Garden, Darwin grand-père’s sensational two-part poem of 1791, orchids are portrayed as “harlot-nymphs” trying to ensnare their hosts:
The scaly monsters roll’d
Ring above ring, in many tangled fold
Close and more close their writhing limbs surround
And fix with foamy teeth the envenom’d wound.
Remember that tangled fold—we’ll come back to tangles later. Charles Darwin, well aware of his grandfather’s love of orchids, became deeply obsessed himself at least from around 1855, but probably earlier (he moved to Down House in 1842). By carefully examining the flowers of orchids he had sent to him by growers and collectors around the world, he learned to deduce from their structure which orchids are pollinated by insects and which are self-pollinated. More than that, he could give a description of the pollinator from the flower alone. When sent specimens of an extraordinary orchid with a flower tube some thirty centimeters long from opening to nectary at the base, he predicted the existence of a moth with a tongue of the same length. It’s the evolutionary equivalent of an astronomer predicting the existence of a planet by its gravitational effect, which is how Neptune was discovered.
Twenty years after Darwin died such a moth was indeed found in Madagascar, and given the species name praedicta to honor the insight. Darwin’s grandfather had thought orchids mimicked insects in order to scare them away and prevent the nectar being stolen: the similarity to a fly or a bee means “it is probable that by this means it may often escape being plundered.” He got it completely the wrong way round. Bee orchids practice what’s called sexual deception mimicry, and they do it in two different phases, visual and chemical. That is, they look and smell like female bees, and they do it in order to attract male bees. Erasmus died a few years before Charles was even born, and what a shame the elder never knew what the younger discovered.
In Darwin’s time violet helleborines didn’t grow around Down House—they’ve been introduced by the gardeners—but Darwin would have been delighted. He was particularly keen on a related species, the marsh helleborine, and had specimens sent to him for study. “The examination of that species,” he wrote to a botanist supplier, “has been one of my greatest treats, which I owe to you. I fear I am very unreasonable; but this subject is a passion with me.”
Violet helleborines are incredibly picky orchids, requiring a mature beech forest growing on a clay soil overlaid on chalk. Darwin knew this. One of the reasons he picked Down House when making the move from London was for its geology, as the village of Downe is on the border of the clay-rich Thames basin and the chalk downs, meaning that the area, at this inter-face of rock types, would be particularly species-rich. He didn’t know the reason that helleborines can endure the deep gloom of the forest floor; he didn’t know that they obtain food from the fungal threads radiating from their roots into the soil and meshing with the roots of the beech trees. Some orchids shirk their green nature completely, becoming albino and relying completely—parasitically, one might say—on food from the fungal network.
By 1858 Darwin had carefully examined around a hundred flowers of Orchis muscifera (the fly orchid) and was preparing to immerse himself completely in orchid work when, around June 18, a letter arrived from a certain Alfred Russel Wallace. Darwin knew of him vaguely, as Wallace had written to him once before. But this letter was different. Born in 1823 (at the time Darwin was a schoolboy collecting insects and rocks), Wallace had spent the last eight years exploring the Malay Archipelago of Indonesia, Malaysia and Papua New Guinea and making quite a name for himself as a naturalist.
Laid up in bed with a fever, Wallace, who had just read Malthus (Darwin read him in 1838) and had been thinking long about evolution, had an insight into how species could change over time. He didn’t call it natural selection, but it was the same idea, based around competition: more individuals are born than can survive, some are better able to survive than others, the difference is heritable, therefore the survivors’ descendants gradually become adapted to their environments. This theory made up the contents of the letter.
Darwin, by then forty-nine and not in the greatest health, was staggered. Suddenly orchids had to wait. Here was an outline of the same theory that Darwin had spent decades working on. Darwin and Wallace agreed to publish together, and a presentation of their idea was given at the Linnean Society. The next year, 1859, Darwin published On the Origin of Species by Means of Natural Selection. He was able to get it out so quickly because over the years he had been compiling a longer version, practically in secret. I saw the cupboard at Down House where he stashed the manuscript, fearful of the revolution it would unleash.
In 1844 he wrote a letter to his wife asking her, in the event of his sudden death, to send the manuscript to a trusted editor to get it published. What did Emma think when she received it? Had he mentioned it to her first, then just sent the letter so she would have the details about what to do? It doesn’t seem so, from the text. But then for all his modernity as a playful father, the Darwins were members of the Victorian upper class. Perhaps he sent the letter about his potential death so they wouldn’t have the discomfort of talking about it. And it’s hard to deduce Emma’s feelings from her appointments diary. When her husband did eventually die, on April 19, 1882, the entry, in its entirety, states “fatal attack at 12.”
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As it turned out, it helped that Darwin had to pause his work on orchids. When his orchid book was finally published in 1862, he was able to use it to answer many of the criticisms of natural selection that had been leveled at him in the previous few years. But the symbiotic essence of orchids, the key to their immense evolutionary and ecological success, remained unknown until the end of nineteenth century. Even then, the orchid-fungal symbiosis was seen as a quirk of their nature. Even now, it is seen as that, rather than the partnership that is key to the success of one of the biggest flower families, and an example of a process that drives and perforates all of life.
Bernard and Loudon, Darwins Erasmus and Charles: they had the courage and vision to imagine unheard-of possibilities.
Much remains unknown. The arrangement works well enough for the orchid, but what about for the fungus? In most cases the fungus receives sugars made from photosynthesis in return for the nutrients it provides the orchid. That’s not the case in flowers with no chlorophyll, such as the bird’s-nest orchid. They cheat—they parasitize the fungus without giving anything in return. But even “normal” orchids, ones that photosynthesize, dip into supplies from the fungal bank more than once thought.
Our understanding changes. At one time, all orchids were thought to be parasites on trees. It took a pioneering writer on gardening and orchids, Jane Loudon, to show otherwise.
Loudon, who died in 1858, a year before Darwin published the Origin, was a woman ahead of her time. In 1827, when she was twenty, she published an extraordinary science fiction novel, The Mummy!, about the Egyptian pharaoh Cheops, brought back to life in the year 2126. (Possibly she was inspired by the example of Mary Shelley, who had published Frankenstein, aged twenty, in 1818.)
She was also a trail-blazing writer on gardening, and especially orchids, which at the time was not considered a pastime for women (well, nor was studying, nor voting, nor having the rights afforded to men). Orchids are not parasites, she wrote, but epiphytes, living on trees, not tapping into them. She wrote of a species called monkey’s-throat orchid, “it has a most singular red and yellow flower, part of which resembles a skeleton’s head with the vertebrae of the neck, and part two folded bat’s wings.” Most orchids are in fact epiphytes; they perch high on the branches of trees, a shortcut to light and exposed to wind, if they need wind to be pollinated.
And the fungal connection that Noël Bernard first discovered, the thread that enters the cells of the developing orchid, extends out of the cells and seeds and the roots and into the bark of the tree. It grows through the bark and into the roots and seeds and cells of other orchids. DNA analysis of the fungi in the orchid roots and the bark of trees shows that orchids on the same tree are connected by the same fungal mass.
Bernard and Loudon, Darwins Erasmus and Charles: they had the courage and vision to imagine unheard-of possibilities; I like to imagine their reaction if we could tell them that orchids on trees and on the ground are linked by a fungal network, and that symbiosis is the driver behind the vast success of orchids in time and space.
What would Erasmus have made of an extraordinary orchid from Peru, Telipogon peruvianus ? He knew of the bee orchid and the fly orchid, mimics of insects, even if he got the explanation wrong. Telipogon mimics two organisms: a fly feeding on a flower. The shape and patterning on Telipogon resembles that of species of daisy with yellow ray florets that a particular species of fly feeds on. But in the center of the flower is a structure that mimics the fly. The lure of both the flower that the fly feeds on, and the female fly herself, proves a powerful combination for the male. He doesn’t actually copulate with the flower, as happens in some other species, but goes through his elaborate foreplay—pre-copulatory behavior, as it is termed—which is enough to pollinate the flower. When orchids are rare and hard to find, you need all the attractive power you can muster. In China, there is the only known example of a mammal-pollinated orchid. The flower, Cymbidium serratum, has green petals but a brightly colored lip, or labellum, which is sweet, a tasty treat for the wild mountain mouse. When the mouse eats the labellum, it is daubed with pollen which it transfers to the next flower on the food stop.
An even more intriguing “what if” is what if Charles Darwin had known that orchids send food packages to their offspring, via the underground fungal network? Orchid obsessive that he was, Darwin had probably observed that wild orchids often turn up in clusters. You might find an adult plant, and then notice several younger plants scattered around it. Orchid seedlings don’t contain chlorophyll, so are unable to photosynthesize and in the wild rely entirely on sugar donated from mycorrhizal fungi to germinate and grow. But could the clusters around adult plants mean the seedlings are getting nutrition from their parent?
Through painstaking experiments in 2023, botanists at the University of Sheffield grew common spotted orchids in a growth medium in the lab. Orchids are notoriously fiddly to grow, and it took the mystifying addition of a dash of pineapple juice to coax the spotted orchid seeds to germinate. Once they had the plants connected to a fungal network and growing in the lab, the team fed them with carbon dioxide “labeled” with a mildly radioactive carbon atom. This allowed the botanists to trace the path of the CO2 as it was taken from the air and made into sugars by photosynthesis. Then they followed the sugars into the fungal network underground where it went to feed orchid seedlings that had not yet developed their chlorophyll. Parental nurture, botanist Katie Field calls it. Katie showed me the orchids growing in their pineapple-laced medium. The contrast between what they looked like, weirdly isolated in a lab setting, and what they were showing—care for their off-spring delivered by a postal service run by another species—was stark.
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From Togetherness: Symbiosis and the Hidden Story of Life’s Greatest Collaborations by Rowan Hooper. Copyright © 2026. Available from Alfred A. Knopf, an imprint of Knopf Doubleday Publishing Group, a division of Penguin Random House, LLC.