The scientific expeditions of the 18th century were more than mere voyages of discovery; they were perilous odysseys that often consumed the lives of the men who undertook them. Among the most tragic and scientifically rich of these narratives is the story of Joseph de Jussieu, a brilliant French botanist whose decades in South America—specifically his long residence in Tarija—produced a legacy of "memories" and manuscripts that continue to fascinate historians of science. Unlike his famous brothers Antoine and Bernard, who built their reputations within the halls of the Jardin du Roi in Paris, Joseph’s laboratory was the unforgiving terrain of the Andes, and his publications were scattered, lost, or published posthumously by others.
The Jussieu Dynasty and the Call of the Equator
To understand Joseph de Jussieu, one must first appreciate the intellectual weight of his family name. The Jussieus were the royalty of French botany. By the 1730s, they had revolutionized plant classification, moving away from the rigid, artificial systems of the past toward a "natural method" based on morphological affinities. When the French Academy of Sciences organized the Geodesic Mission to the Equator (1735–1744) to measure the Earth’s meridian arc and settle the debate between Newtonians and Cartesians regarding the planet's shape, they needed a botanist of the highest caliber. Joseph, then in his early thirties and already a corresponding member of the Academy, was the obvious choice.
This is the bit that actually matters in practice.
He joined a formidable team including Charles Marie de La Condamine, Pierre Bouguer, and Louis Godin. What was planned as a few years of work stretched into decades for Joseph. So the mission landed in Quito (modern-day Ecuador) in 1736. Still, while the surveyors triangulated mountains, Joseph was tasked with a comprehensive natural history survey: collecting specimens, describing flora, studying cinchona (the source of quinine), and observing the natural resources of the Spanish colonies. While his colleagues eventually returned to France—some to fame, others to obscurity—Joseph remained, trapped by a combination of scientific obsession, financial ruin, political bureaucracy, and declining mental health.
Tarija: A Forced Retreat and a Botanical Haven
By the early 1750s, the geodesic measurements were complete. La Condamine had returned to Paris via the Amazon. Practically speaking, joseph, however, stayed in South America, ostensibly to finish his botanical treatise. Practically speaking, he drifted between Quito, Lima, and Potosí, his health deteriorating and his funds exhausted. The Spanish Crown, initially supportive, grew suspicious of a Frenchman mapping their resources, and the Jesuits—who often facilitated scientific travel—were expelled in 1767, severing a vital support network.
It was during this twilight period that Tarija enters the narrative. For a botanist, it was a transition zone of extraordinary biodiversity. Still, located in what is now southern Bolivia, Tarija offered a unique microclimate: a temperate valley nestled between high Andean peaks and the Chaco lowlands. Joseph de Jussieu settled there around the 1760s, living in relative obscurity compared to the grandeur of the Parisian salons he had left behind.
His "memories" of Tarija are not a single published diary but a constellation of manuscript notes, letters to European correspondents, herbarium labels, and observations recorded by travelers who visited him. He cultivated European vegetables alongside native species, experimented with the acclimatization of cinchona trees, and meticulously documented the materia medica of the local Indigenous populations. That's why he transformed his residence into a makeshift research station. The "Tarija memories" represent the raw, unfiltered data of a man racing against time and infirmity to classify a flora that was entirely new to European science.
The Content of the Lost Books and Manuscripts
The tragedy of Joseph de Jussieu lies in the disconnect between his immense output and his published record. He did not produce a single, cohesive "Flora of Tarija" or a polished travelogue during his lifetime. Instead, his legacy survives in fragments:
1. The Cinchona Obsession His most commercially vital work concerned the "Jesuit’s Bark." Joseph spent years distinguishing between Cinchona officinalis, C. calisaya, and other species. His notes from Tarija detail the specific altitudes, soil compositions, and harvesting techniques that yielded the highest quinine content. These "memories" were essentially industrial espionage for the French state, intended to break the Spanish monopoly. While he never published a definitive treatise, his data fed into the works of later botanists like Ruiz and Pavón, and eventually enabled the Dutch and British to establish plantations in Java.
2. The "Natural Method" in the Field Joseph applied his family’s natural classification system in real-time. His manuscript descriptions from the Tarija period show him grouping plants by floral structure (corolla, stamens, pistils) rather than the Linnaean sexual system which was then dominating Europe. He recognized families like Solanaceae, Compositae, and Leguminosae in the field, often assigning them vernacular names alongside Latin binomials. These field notes are invaluable to modern taxonomists trying to type-specimens for species described later by others based on his dried collections.
3. Ethnobotany and Indigenous Knowledge Perhaps the most human aspect of his Tarija writings is his reliance on local knowledge. He did not merely "discover" plants; he learned their uses from the Chiriguanos, Tomatas, and Chané peoples. His notes record treatments for altitude sickness (soroche), dysentery, and fevers using native species like Coca (Erythroxylum coca), Quinoa (Chenopodium quinoa), and various Baccharis species. These entries read less like a botanist’s log and more like an ethnographer’s journal, preserving Indigenous pharmacopeia that might otherwise have been lost Not complicated — just consistent..
4. Geological and Meteorological Diaries Living in a valley prone to flash floods and seismic activity, Joseph kept detailed weather logs and geological observations. He noted the stratification of the valley floor, the fossil beds suggesting a prehistoric lake, and the seasonal rhythms that dictated planting cycles. These "memories" anticipated the work of Alexander von Humboldt by half a century, treating the landscape as an interconnected system rather than a cabinet of curiosities.
The Shadow of Madness and the Fate of the Papers
The term "memories" takes on a darker tone when considering Joseph’s mental state. Contemporary accounts—most notably from the Spanish botanist Juan Tafalla and the Italian naturalist Dombey, who visited him in Tarija—describe a man slipping into paranoia and dementia. He became convinced his rivals were stealing his work. He hid bundles of manuscripts in walls, buried boxes in the garden, and entrusted crates to muleteers who never arrived in Buenos Aires or Cadiz Worth knowing..
When Joseph de Jussieu died in Tarija in 1779 (some sources say 1780), he left behind a chaotic archive. His nephew, Antoine Laurent de Jussieu (the famous author of Genera Plantarum), spent years trying to recover the estate. The Spanish authorities sealed his rooms. Crates were shipped to Cadiz, but many were lost to shipwreck, customs corruption, or simple neglect. What survived formed the basis of the Jussieu Herbarium in Paris, but the narrative context—the "books" he intended to write—was largely fragmented Worth keeping that in mind..
The Posthumous Reconstruction: Books Built from Memories
Because Joseph failed to publish, his "books" were effectively written for him by the next generation of scientists who mined his collections It's one of those things that adds up..
- Ruiz and Pavón’s Flora Peruviana et Chilensis (1798–1802): The
