Chief among the many wonders encountered by Renaissance explorers were the novel plants never before seen in Europe. In Spanish geographer Martín Fernández de Enciso’s 1519 account of his experiences in the Americas, “La Suma de Geografía,” he described a delectable new fruit, writing, “when it is ready for eating it turns yellowish; that which it contains is like butter and is of marvelous flavor, so good and pleasing to the palate.”
By the time avocados made their US debut in the 19th century, they were called alligator pears. Botanists dubbed them persea americana, following the binomial nomenclature, or two-worded name, devised in the 18th century by Swedish physician and botanist, Carl Linnaeus, whose pamphlet-sized first edition of Systema Naturae quickly expanded to an encyclopedic work. Linnaean taxonomy eventually set the stage for our hierarchical system of classification for flora and fauna—from kingdom down to species. By then, the golden age of plant hunting was well underway. European explorers had collected, exchanged, and cultivated so many varieties of plants from around the world that a logical classification system was sorely needed.
In a November 1922 story, Popular Science contributing writer E. L. Jones chronicled the ongoing efforts of early 20th century plant hunters to bring back promising species new to the US, such as the “Guatemalan avocado, a fruit more nourishing than bread or rice.” Since then, the mode of plant hunting—and the impetus—has changed, but even in the 21st century, the hunt for undiscovered, undocumented, and endangered species continues. Today, plant hunters, chiefly botanists and horticulturists, tend to focus their efforts on safeguarding endangered species and finding new candidates for drugs.
Cassandra Quave, an ethnobotanist and author of The Plant Hunter: A Scientist’s Quest for Nature’s Next Medicines, hunts for promising new drug candidates by exploring medicinal plants used in remote and rural communities across the world. In her lab at Emory University, Quave has studied more than 750 plant species. “We look to the remedies people are already using,” she says, “and tease apart their chemical complexity to identify which molecules are tied to which pharmacological properties.” Quave has hunted for medicinal plants across the globe, such as in the Peruvian Amazon, Egypt, South Africa, the Balkans, and closer to home in the southeast US.
For centuries, colonialization by expanding European empires funded the expeditions and provided the means for naturalists to explore other lands, and collect and trade indigenous plant species. English plant hunter Sir Joseph Banks accompanied legendary Captain Cook in the 18th century to bring back specimens from South America, New Zealand, and Australia. Bucking the plant-hunting boys’ club, wealthy naturalist Marianne North traveled the world for 14 years (1871–1884), documenting plant species through art. Her exquisite collection of more than 800 paintings remain on display at London’s Kew gardens.
In his 1922 story, Jones described, with a sense of awe, the many species brought to the US, such as the “Columbian giant blackberry, the world’s largest edible berry, growing to a length of 2 ½ inches.” Since Jones’s story was based on an interview with then US Secretary of Agriculture, Henry C. Wallace, he highlighted the economic boon associated with cultivating crops new to America. “California,” he wrote, “ is now able to market in excess of 13,000,000 boxes of navel oranges annually, as a result of the introduction of this fruit from Brazil.” A century later, that output has risen to 74 million cartons, according to the USDA.
But Jones also chronicled the extent to which some plant hunters would go to discover species unknown to them, such as Frank N. Meyer, who served the USDA for more than a decade as Agricultural Explorer of the Office of Foreign Seed and Plant Introduction. Meyer spent most of his time traveling through Russia and China, collecting species new to the US.
“He walked over 10,000 miles in search of agricultural gems,” Jones wrote. “Alone and far from help, he fought off Chinese ruffians who sought to hinder his work.” Meyers eventually lost his life in 1918, drowning in the Yangtze River during a plant-hunting expedition. By then, however, he had “gathered and transmitted to Washington thousands of plants that have enriched the fortunes of many farmers.” In tribute to Meyers, for more than a century, the USDA has awarded the Frank N. Meyer Medal for Plant Genetic Resources annually to individuals for distinctive plant hunting, protection, and classification work.
The golden age of plant hunting may have enabled the discovery and classification of a vast swath of Earth’s plant species, but it also had a dark side. For centuries, imperial powers would take plants from different parts of the world to cultivate them where they had lands, such as in the Caribbean islands, often taking advantage of slave labor and reaping the benefits. According to Quave, plant hunting’s legacy was mostly about “looking for tangible ingredients for the economic benefits of a nation.” That’s why it’s no surprise that Jones’s 1922 article has a shameless Western bias centered on economic gain. Today, the international Nagoya Protocol on Access and Benefit Sharing protects native countries from such biopiracy. Plant hunters can still hunt for species across the world, a practice now referred to as bioprospecting, but they must share any benefits with origin countries.
The frenzy of botanical exploration and global plant exchange that marked the golden age of plant hunting may have ended more than a century ago, but plant hunters still brave challenging conditions to discover Earth’s remaining hidden species, and there are many. A 2023 report from the Royal Botanical Gardens, or Kew Gardens, offers the first ever “World Checklist of Vascular Plants”—a catalog of 350,386 known plant species. In the report, researchers estimate that at least 15 percent of the world’s plants have yet to be found and documented.
But plant hunting has taken on a new challenge—collecting and preserving endangered species. The RBG Kew researchers’ predictive models suggest that nearly half the world’s flowering plants are threatened with extinction. Some of these endangered plants, as well as undiscovered specimens, provide more than decorative garden foliage or delicious fruit. Quave estimates that there are “around 35,000 species of medicinal plants on Earth.” Of these, only a small fraction have been examined closely in labs like Quave’s to fully understand their chemical makeup.
Besides well-known medicines like aspirin (acetyl salicylic acid), which was originally taken from willow bark, or penicillin, which comes from mold, some of today’s most promising drugs derive directly from plant molecules. Oncavin, a chemotherapy drug used to treat Hodgkin’s lymphoma and other cancers, comes from the Madagascar periwinkle, a hardy plant with white, pink, and purple flowers now found in nurseries and gardens around the world. Paclitaxel, a chemotherapy drug for breast cancer patients, comes from the bark of the Pacific Yew tree. Digoxin, a drug used to improve heart muscle contractions for patients with congestive heart failure, comes from the ornamental—and toxic, if ingested—foxglove plant.
Quave’s passion for plant hunting can be traced to her roots. “I grew up in rural Florida,” she says, “and spent a lot of time out in the woods with my dad.” But it was a trip to the Peruvian Amazon in her early twenties that sparked her interest in ethnobotany and quest for medicinal plants. “I spent time with an indigenous healer,” she explains. “And I came to the realization that so much of nature’s medicines had yet to be explored.”
Even today, anyone daring to trek into remote regions of the world, like the Peruvian Amazon, to spy native “gems” will likely suffer at least some of the hardships endured by classic plant hunters. From mountain roads that are really just “goat paths,” says Quave, to traveling by dugout canoe through tropical rainforests, extreme plant hunting comes with myriad physical hardships. Quave has an additional challenge—as a person with a limb difference, she wears a prosthetic below her right knee. “The rubbing from walking in a very humid rainforest is really hard on my skin,” she says, “because you’re constantly sweating and you get that friction, and so it makes my skin more prone to infections.” But Quave has learned to adapt by finding local mounts to ride, like donkeys in the Balkan mountains, camels in the Egyptian desert, and airboats in rural Florida.
In her own lab, Quave focuses on remedies to help patients overcome drug-resistant infections, like MRSA, a type of staph bacteria. Rather than targeting a new antibiotic, however, she’s discovered molecules that reverse antibiotic resistance. Based on her lab’s research, she’s already founded two companies, PhyoTEK LLC and Verdant Scientific. PhyoTEK’s prospective drug is based on botanical extracts from Mediterranean blackberry roots, which are good at preventing bacteria from sticking to surfaces and might enhance wound care. Verdant Scientific, Quave’s latest company, is based on her work with the Peruvian pepper tree.
In 1922, Jones lamented the under-appreciation for plant hunters. “Their only goal,” he wrote, “through all the suffering and privation, is a mere plant which, introduced into the agricultural life of America, may add, it is hoped, to the farm wealth and food resources of this country.” It’s likely that plant hunters today are equally under-appreciated, but for many their goal focuses on humanity’s collective welfare and well-being as they pursue and study promising specimens. “So they can be developed into medicines,” Quave says, “to help people across the globe.”