Where millipedes grow more than six feet long

Reading Riley Black’s When the Earth Was Green for New Scientist, 26 February 2025

Plants are boring. Their behaviours are invisible to the naked eye, they operate on timescales our imaginations cannot entertain (however much we strain them), and they run roughshod over familiar categories of self, other and community.

Wandering among (or is it through?) a 14,000-year old aspen clone (or should that be “a stand of aspen trees?”), palaeontologist Riley Black wonders, “how many living things have alighted on, chewed up, dwelled within, pushed over, and otherwise had a brush with a tree so enduring it probably understands the nature of time better than I ever will?”

When the Earth Was Green is a paean to plants. It’s a series of vignettes, each seperated from its neighbours by gaps of millions, tens of millions, sometimes hundreds of millions of years. It’s an account of how vegetable and animal life co-evolved. It’s not as immediately startling as Black’s last book, 2022’s The Last Days of the Dinosaurs, but it’s a worthy successor: as I wrote of Last Days, “this is palaeontology written with the immediacy of natural history”.

If you winced just now at the twee idea of a tree “understanding time”, you may want to hurry past Black’s last chapter — a virtue-signalling hymnal to the queerness of trees. This crabbed reviewer comes across many such passages, and reckons they’re getting increasingly formulaic. Black, seemingly unaware of the irony, pokes gentle fun at an earlier rhetoric that imagined, say, tideline plants “colonising” and “invading” the land. Maybe all writers who attempt to engage with plants suffer this fate: the rhetorical tools they stretch for will date far faster than their science.

Riley excels at conveying life’s precarity. Life does not “recover” or “regenerate” after extinction events. It reinvents itself. Early on — 425 million years ago, to be exact — we find life flourishing in strange lands, under skies so short of oxygen, fires can only smoulder and dead plants cannot decompose. When oxygen levels rise, existing insect species grow gigantic in a desperate (and, ultimately, losing) battle to elude its toxic effects. When an asteroid brings the Cretaceous Period to a fiery end, 66 million years ago, we find surviving plant species innovating unexpected relationships with their surviving pollinators. 15,000 years ago the planet grew so verdant, some plant species could afford to abandon photosynthesis entirely, and simply parasitise their neighbours.

Adaptation is a two-edged sword in such a changeable world. It allows you to take full advantage of today’s ecosystems, but how will you cope with tomorrow’s? Remaining unspecialised has allowed the Ginkgo tree to survive the world’s worst catastrophe and persist for millions and millions of years.

Black allows her imagination full rein. Wandering through a dense, warm, humid, million-year-old forest in Ohio, where “millipedes grow more than six feet long and alligator-size amphibians silently watch the shoreline for unwary insects,” the reader may wonder where the science stops and the speculation begins. Riley’s extensive endnotes explain the limits of our current knowledge and the logic behind her rare fancies. These passages are integral to the text and include some of her most insightful writing.

Above all, this is a book about how animals and plants shape each other. When animals large enough to knock over trees disappeared, forests grew more dense, with a continuous overstory that gave even large animals a third dimension to explore. Thick forests forced surviving mammals and surviving dinosaurs into novel shapes and, even more important, novel behaviours. Both classes learned to spend more time with their young. And, if we’re prepared to cherry-pick our mammalian examples, we can just about say that both learned to fly.

When the Earth Was Green may be too cutesy for some. The sight of a couple of sabercats rolling about in a patch of catnip will either enchant you or, well, it won’t. And I still think plants are boring. I’d happily pulp the lot of them to make books as fascinating as this one.

How to appropriate a plant

Visiting “Rooted Beings” at Wellcome Collection, London for the Telegraph, 24 March 2022

“Take a moment to draw a cosmic breath with your whole body, slower than any breath you have ever taken in your life.” Over headphones, Eduardo Navarro and philosopher Michael Marder guide my contemplation of Navarro’s drawings, where human figures send roots into the ground and reach with hands-made-leaves into the sky. They’re drawn with charcoal and natural pigments on envelopes containing the seeds of London plane trees. When the exhibition is over, the envelopes will be planted in a rite of burial and rebirth.

What are plants? Garden-centre curios? Magical objects? Medicines? Or trade goods? It’s hard for us to think of plants outside of the uses we put them to, and the five altars of Vegetal Matrix by Chilean artist Patricia Dominguez celebrate (if that is quite the word) their multiple social identities. One shrine contains a medicinal bark, quinine; in another, flowers of toxic Brugmansia, an assassin’s stock-in-trade; In the third sits a mandrake root, carved into the shape of a woman. Dominguez’s artistic research sits at the centre of a section of the exhibition entitled “Colonial violence and indigenous knowledge”.

Going by the show’s interpretative material, the narrowly extractive use of plants is a white western idea. But the most exciting exhibits reveal otherwise. From 400 CE there’s a fragment of the world’s earliest surviving herbal, painted on papyrus (we have always admired plants for what we could get out of them). Also from the Wellcome archives, there’s a complex map describing the vegetal “middle realm” of Jain cosmology — obviously a serious effort to establish an intellectual hold on the blooming and buzzing confusion of the plant world. Trees and their associated wildlife are reduced to deceptively simple and captivating shapes in the work on paper of the artist Joseca, whose people, the Yanomami, have been extracting foods and medicines from the Amazon rainforest for generations. His vivid plant portraits are not some classic Linnaean effort at the classification of species, but emotionally they’re not far off. Joseca is establishing categories, not tearing them down.

Bracketing the section about how imperial forces have “appropriated” useful plants (and thank goodness for that! cries the crabbed reviewer, thinking of his stomach as usual) are more introspective spaces. Ingela Ihrman’s enormous Passion Flower costume dominates the first room: time your visit just right, and you will find the artist inhabiting the flower, and may even get to drink her nectar. Not much less playful are the absurdist visions — in textile, embroidery and collage — of Gözde Ilkin, for whom categories (between human and plant, between plant and fungi) exist to be demolished, creating peculiar, and peculiarly endearing vegetal-anthropoid forms.

“Wilderness” is the theme of the final room. There’s real desperation in the RESOLVE Collective’s effort to knap and chisel their way towards a wild relationship with the urban environment. Made of broken masonry and pipework, crates and split paving slabs, this, perhaps, is a glimpse of the Hobbesian wilderness that civilisation keeps at bay.

Nearby, Den 3 is the artist SOP’s wry evocation of the old romantic mistake, cladding misanthropy in the motley of the greenwood. Rather than vegetate on the couch during the Covid-19 pandemic, SOP built a den in nearby woods and there enjoyed a sort of pint-size “Walden Pond” experience — until lockdown relaxed and others began visiting the wood.

At its simplest, Rooted Beings evokes a pleasant fantasy of human-vegetable co-existence. But forget its emolient exterior: at its best this show is deeply uncanny. The gulfs that exist between plant and animal, between species and species, between us and other, serve their own purposes, and attempts to do as Navarro and Marder suggest, and experience the world as a plant might experience it, are as likely to end in horror as in delight. “As you are very slowly dying while also staying alive,” they explain, “your body becomes the soil you are living in.” Crikey.