Palm basket from Botswana in the Kew Economic Botany Collection
As the twentieth century progressed and economic botany went into decline (see last post), ethnobotany developed and incorporated some of the former’s collections and concepts. Merlin Sheldrake (2020) defines ethnobotany as the study of the relationships among plants and people, in other words, learning about plants through people’s attitudes towards and uses of them. Because ethnobotany grew out of studies of plants and indigenous peoples, its emphasis has been on plant use among these populations and is often related to anthropological studies. Richard Schultes was a botanist instrumental in making the transition from economic botany to ethnobotany. He studied economic botany with Harvard’s Oakes Ames in the 1930s and wrote his undergraduate thesis on the use of peyote cactus as a hallucinogen among the Kiowa people of Oklahoma. Schultes went on to pursue both taxonomy and ethnobotany. Like many botanists who are involved in more than one facet of the science, he collected specimens because he needed to be able to identify the species he found in the field and to study their relationships not only to human use but to each other (Ponman & Bussmann, 2012).
Oakes Ames had early warned of the need to learn as much as possible about plants and their uses from indigenous peoples because they and their life styles were so vulnerable. Schultes heeded his mentor’s warning and recorded much about the peoples he studied within tropical South America, especially their use of hallucinogenic plants in religious rituals. He wrote a great deal and also educated the next generation of ethnobotanists. Ethnobiology is still evolving as a discipline, and in the 21st century it is becoming more central to efforts to promote conservation, equitable distribution of resources, and sustainability.
In the second half of the 20th century, pharmaceutical companies funded many expeditions with the goal of finding plant-derived active substances. About a quarter of prescription drugs are produced from plant materials or based on chemicals first found in plants, so this strategy makes sense. There are two approaches to plant hunting for pharmaceuticals. One is to collect enough material from an array of plants in a region to test each for chemicals such as alkaloids, a molecular class that includes many drugs. Interesting substances have been discovered this way, but it is rather hit or miss (Blumberg, 1998).
The other approach to drug discovery is to partner with indigenous peoples, particularly with healers who use local plants to treat a variety of maladies. This has been done since the arrival of the first European explorers, but now the work is much more respectful of local knowledge. Experts in ethnobotany live with indigenous peoples and make it a practice to learn the languages of the groups they work with, understanding the culture as well as the plants and studying healing practices and other uses of plant materials (Balick & Cox, 1996). Ethnobotany provides a more holistic approach to drug discovery, studying the culture as a whole. In some locales for example, palms are pivotal plants as sources not only of medicines, but of food, building materials, containers, and even cloth (See image above).
Abena Osseo-Asare (2014) investigated efforts to develop drugs from African medicinal plants and discovered that researchers often consulted the herbaria of colonizers to find likely locations for plants that might yield active ingredients. So even though African nations had achieved independence, colonial influence remained. However, she also found it difficult to create a simple narrative of exploitation. Drug development is a complex process, and most areas of Africa do not yet have the infrastructure for research and development independent of multinational corporations. Osseo-Asare’s research also revealed that many likely medicines were hardly new to science, their existence had long been known and could not be attributed to a particular indigenous group or area. This meant that compensation would be difficult to negotiate. Robert Voeks (2018) has also questioned the “jungle medicine narrative,” writing from his perspective as a botanist who spent much time in the tropics studying medicinal plants. He has great respect for indigenous knowledge, but is less positive about how likely it is that useful drugs can arise from these resources because the diseases of the developed and developing worlds are so different from each other.
Ethnobotanical research, for medical or other aims, requires herbarium vouchers to document the plants discussed in reports and other publications. Having a preserved specimen, a voucher, allows future investigators to verify the species tested. Also, since herbal medicines are essentially formulations of plant material, it is considered good practice in their manufacture to voucher each batch of plants used, though the term “batch” can mean many different things. Ideally, it would be the plants collected in a certain place at one time by a single collector or group working together. This is not always feasible, but it is definitely a useful goal (Eisenman et al., 2012).
Balick, M. J., & Cox, P. A. (1996). Plants, People, and Culture: The Science of Ethnobotany. New York: Scientific American.
Blumberg, B. S. (1998). Case Study of Plant-Derived Drug Research: Phyllanthus and Hepatitis B Virus. In T. R. Tomlinson & A. Olayiwola (Eds.), Medicinal Plants: Their Role in Health and Biodiversity. (pp. 3–10). Philadelphia: University of Pennsylvania Press.
Eisenman, S., Tucker, A., & Struwe, L. (2012). Voucher specimens are essential for documenting source material used in medicinal plant investigations. Journal of Medicinally Active Plants, 1(1), 30–43.
Osseo-Asare, A. D. (2014). Bitter Roots: The Search for Healing Plants in Africa. Chicago: University of Chicago Press.
Ponman, B. E., & Bussmann, R. W. (Eds.). (2012). Medicinal Plants and the Legacy of Richard E. Schultes. St. Louis: Missouri Botanical Garden.
Sheldrake, M. (2020). The ‘enigma’ of Richard Schultes, Amazonian hallucinogenic plants, and the limits of ethnobotany. Social Studies of Science, 50(3), 345–376. https://doi.org/10.1177/0306312720920362
Voeks, R. A. (2018). The Ethnobotany of Eden: Rethinking the Jungle Medicine Narrative. Chicago: University of Chicago Press.