Luke Keogh. The Wardian Case: How a Simple Box Moved Plants and Changed the World. The University of Chicago Press and the Royal Botanic Gardens, Kew, 2020.
On December 18, 1994, three cave explorers squeezed into an opening of a cliff overlooking the Ardèche River in southern France. At the back, a whisper of cool air prompted them to prize stones from a narrow passage and worm forward headfirst. After ten feet, they encountered a thirty-foot drop into a large chamber. Beneath them, as it turned out, the cave walls were covered with paintings. Some appeared almost fresh. First, the explorers found a mammoth drawn in red pigment, then woolly rhinoceroses, cave lions, and compositions made entirely of human handprints.
Researchers would later determine that a landslide sealed the main entrance to the cave, now known as Chauvet Cave, twenty-eight thousand years ago, safeguarding hundreds of paintings and wall engravings. Eighteen thousand years later, glaciers had retreated from much of Europe, and many of the animals depicted in Chauvet Cave had gone extinct. Humans in Mesopotamia were domesticating wheat and barley. Fast forward another nine thousand years to the completion of the first recorded circumnavigation of the globe in 1522.
Eventually, in the summer of 1833, an English sailing ship departed London, bound for Australia. On the upper deck, the captain diligently monitored two sealed glass cases planted with ferns, grasses, and mosses. About six months later, the ship arrived in Sydney with all but three of the plants still alive. The case was opened only once; moisture cycled naturally inside the enclosure. On the return trip, the cases were packed with ferns that survived air temperatures fluctuating between twenty and more than ninety degrees Fahrenheit. In fact, the cases were so effective that stowaway seeds germinated in the soil.
A shipment of plants between the antipodes might seem like a minor historical footnote, but in a new book, The Wardian Case: How a Simple Box Moved Plants and Changed the World, historian Luke Keogh describes the shipment as a profound inflection point in the history of the Earth. Keogh firstbecame interested in these enclosed glass cases while curating an exhibit at the Deutsches Museum in Munich. The exhibit opened in 2014 and focused on the Anthropocene, a term for our current geologic era that acknowledges the enormity of human-caused environmental change. Millions of years from now, our present moment will appear in the geologic record as an abrupt transition characterized by rapid climate change, sea-level rise, and mass extinction—an imprint far more permanent than the markings at Chauvet Cave. The unprecedented biotic exchange ushered in by the experimental plant shipments between London and Sydney is a piece of this story.
The experiments had been orchestrated by an affable English physician named Nathanial Ward and the nurseryman George Loddiges. Previously, it had been exceptionally difficult to ship live plants over such long distances. In addition to the general perils of sea travel (salt spray, tempestuous weather, foraging rodents), fresh water was a scarce resource and could seldom be spared for plants. In a backyard experiment, Ward discovered that plants could be sustained within an enclosed glass container for long periods without supplemental water. When such cases were used aboard ships, they solved many of the persistent problems associated with long-distance plant transport. In a follow-up experiment in 1834, Ward sent six cases to Egypt and Syria, and when the plants were received, scarcely a leaf was reported missing.
Keogh follows the Wardian case as it became a commonplace tool, not only for moving botanical curiosities but also for transporting crops (including tea, Camellia sinensis, and rubber, Hevea brasiliensis) that supported the endeavors of Western empire-building. Also, because Wardian cases contained soil, the plants invariably arrived with insects and pathogens in tow. “To move plants was to move ecosystems,” Keogh writes. Some of these newcomers proved devasting, including coffee rust (Hemileia vastatrix), which erupted in Ceylon (now Sri Lanka) in 1869 and subsequently decimated plantations in many coffee-growing regions around the world. Altogether, this global churning—which continues in a post-Wardian world—accumulates to dramatic effect. Keogh, for instance, cites a study suggesting that approximately nine out of ten invertebrate pests in the United Kingdom arrived on live plants.
Certainly, the Wardian case was just one innovation within the broader scope of the Anthropocene. The case gained traction at a moment of enormous industrialization and fossil fuel use. While the first Wardian cases were transported on sailing ships, steam power soon predominated. Carbon dioxide levels in the atmosphere would mount. Moreover, industrial agriculture favors monocultures, which are especially susceptible to pests and pathogens (like coffee rust) that spread rapidly in the Wardian era. In a curious twist, Keogh recounts how, in the early twentieth century, entomologists used Wardian cases to intentionally transport insects to control invasive plants and other pests that had been imported in earlier shipments.
By the 1920s, plant quarantines and import restrictions slowed the use of Wardian cases, but it was the airplane that finally rendered them obsolete. Now live plants can be moved without soil, wrapped in plastic, and mailed directly to inspection sites before being admitted into a country, assuming importers follow the rules. Yet pests and pathogens continue to spread. The emerald ash borer (Agrilus planipennis) was first identified in the United States in 2002 and likely arrived burrowed within wood shipping materials. The Asian longhorned beetle (Anoplophora glabripennis) arrived in a similar fashion before 1996. In this light, the Wardian case was only one contributor to this dramatic biotic exchange. Not only has the admixture continued to the present but humans began moving plants long before Nathaniel Ward arrived on the scene. Ward’s main innovation, Keogh stresses, was the enclosed system. Also, not insignificantly, Ward was a charismatic individual who used his social connections to promote the case.
For Ward, awaiting news on his inaugural shipment to Australia, the long-term implications of his cases would have been impossible to imagine. Thinking about consequences two hundred years in the future is almost beyond the realm of comprehension—almost as unlikely as the painters at Chauvet Cave imagining researchers studying their work more than thirty thousand years later. Yet the concept of the Anthropocene asks us to think even further ahead. In 1833, the captain of the ship to Australia penned a congratulatory letter to Ward: “Your experiment for the preservation of plants alive … has fully succeeded.” The case of the Anthropocene challenges us to reconsider the meaning of our own small successes.
Jonathan Damery is the editor of Arnoldia.
Citation: Damery, J. 2021. Case of the Anthropocene. Arnoldia, 78(3): 42–43.