The Divine Leaf: Coca, Hayo, Ipadú, and Tupa

Coca: One name, many crops

I must clarify that the name "coca" is an oversimplification of how the people who cultivate this crop refer to it. For many cultures, the word “coca” might be as foreign as “phylogeny”. But in writing about this group of plants, “coca” is a necessary simplification to aid in literary digestion.

What we call coca encompasses four distinct but closely related crops, each originating from separate regions of tropical South America and each holding many levels of landraces and local variations. Thanks to the groundbreaking and seminal work of Dr. Timothy Plowman of Harvard University and then the Field Museum of Natural History, we now have a far more accurate—though still far from adequate—nomenclature to describe the broad diversity of this crop:

·      Coca – This is the name that is most frequently used to describe all four crops. This could be because it was the primary source of leaves for the booming legal cocaine market of the turn of the 20th century, and the most widely cultivated coca variety for traditional use in modern times – mostly among the large Quechua and Aymara populations in Peru and Bolivia. The word "coca" is believed to derive from the Aymara word khoka, meaning "bush." This name is used by people living in the Yungas, or Andes/Amazon montane region, in Bolivia, Peru, and Ecuador. It pertains to the botanical variety Erythroxylum coca var. coca.

·      Ipadú –  This crop is pulverized and consumed as a powder by dozens of cultures in the northwestern Amazon. The name ipadu, picked by Plowman, is frequently encountered along the tributaries of the Rio Negro in Brazil. However, the dozens of other cultures in Colombia and Peru use numerous other names instead, such as ipi and tsihpaa among the Bora and kudu jibina among the Uitoto.

·      Tupa – This is the name used by the Quechua and Inca cultures to describe the crop found today in the arid valleys of northwestern Peru and parts of western Ecuador. This is the coca of international commerce under the strict regulation of the Empresa Nacional de la Coca in Peru and the Stepan Company of New Jersey – a subsidiary of The Coca-Cola company. This variety is classified botanically as Erythroxylum novogranatense var. truxillense (as in Trujillo, Peru).

·      Hayo – The north Andean variety of coca, hayo is the name used in Colombia and Venezuela. The general regional variants of this are ayo and ayú. This hearty and resplendent plant has yellowish-green leaves on long, slender branches and attains the greatest height of all coca varieties. This is reported to be the only variety capable of self-fertilization, and it is resistant to drought—desirable characteristics for farming.

Unfortunately, global discourse often requires us to simplify language, repeatedly referring to these geographically, culturally, and morphologically distinct crops simply as 'coca.' While using four distinct names would be cumbersome in general discussions, this simplification is problematic because it undercuts the cultural and botanical complexity of the crops. It is further compounded by the loss of cultural heritage and linguistic diversity in South America, which has led to the disappearance of many local names that once described the rich variations at even smaller scales. But now, the reader is aware of this issue and can surely understand that 'coca' can refer to this diversity of crops, as well as specifically to the Yungas variety (E. coca var. coca).

“Chewing” coca

Across the continent, the consumption of leaves is generally similar. Following millennia-old traditions in the Andes and Amazon, small and round leaves are picked from the long branches of shrubs that can be two to fifteen feet tall are pest-resistant and adaptable to diverse habitats. Once harvested, the leaves are always toasted—which preserves them and improves flavors. I’ve witnessed leaves being stirred in large earthen bowls over an open fire or toasted by tossing a searing hot rock into a leaf-filled woven bag. Once this process is complete, the leaves are ready for use.

Chewing coca is a simple practice: 5–20 leaves are arranged, placed in the mouth, and gently macerated before being tucked in the cheek. There is no precise word for this action in the English language, but the terms acullicar (Bolivia), cacchar (Peru), and mambear (Colombia), are some of the more common Spanish verbs adopted from Amerindian languages.

Within minutes, an experienced consumer feels a subtle, clear, and focused stimulation akin to drinking a strong cup of tea or coffee, but without the jitters or frequent bathroom trips associated with caffeine. Individuals chewing coca for the first time will likely find it a bit awkward and not feel any effects. That is, unless one uses cal or llipta—a nearly universal additive to coca that is carefully added to the quid to potentiate the effects. This substance comes in many compositions and flavors: powdered limestone or seashells or just sodium bicarbonate—generally called cal in Colombia, or a mixture composed primarily of the ashes of roots or fruit husks from plants like banana, cacao, or quinoa—generally called llipta or tocra in Peru and Bolivia. In the case of ipadú, the pulverized leaves are premixed with the ash of yoruma (Cecropia spp.) leaves or select other species.

Then you get on with your day – working, socializing, or whatever the tasks at hand. Again, the use of coca is not unlike the use of coffee or the chewing of tobacco; and millions of South Americans are consuming the leaves in that way on a daily basis. The leaves are also popular among populations engaged in mentally or physically strenuous activities like long-distance driving or educational studies. Within rural and indigenous cultures, the profound difference lies in the intention behind the act.

The coca crops produce a variety of chemical compounds for their defense against insect herbivores, including nicotine and, most infamously, cocaine. The mild stimulant and medicinal effects of chewing the leaf are not equatable to a cocaine high; in fact some consumers in Bolivia actually prefer sweeter leaves with lower cocaine content.

In the communities that have been farming and using the plant for millenia, coca is much more than a plant; in many regions it has been enriched as a symbol, a sacrament, and a cultural cornerstone. For the indigenous cultures where coca is most integrated, it is almost never absent from community meetings or even colloquial encounters among neighbors. It serves as a daily stimulant, an effective natural medicine, and a powerful symbol of Indigenous autonomy, community cohesion, and the interconnectedness of humans and the Earth. This profound relationship is one that, I believe, most Westerners, myself included, do not have any analog for. Please refer to my article co-authored with Dr. Carol Conzelman for a more proper communication of the uses and transcendental role of coca in societies.

So just how long has this relationship been developing? How do humans take a plant from the wild and adopt it into their daily lives, transforming both the plant itself as well as human behaviors and cultural expressions?

The botanical science

There are no truly wild populations of coca bushes. Like corn, they are a plant found in farms with no wild equivalent. This is called a cultigen. This means that at some point, people identified a wild plant as important, began to harvest it, and over time, through intention or incident, created a new and distinct plant lineage living within farms or human environments. Corn is perhaps our most extreme example of this process—called domestication.

The revolutionary explorer, scientist, and visionary of the interconnection of our biological systems, Alexander Von Humbolt, was the first to publish his guess at what the wild ancestor of coca was (he thought perhaps E. hondense of central Colombia). Many other pioneering botanists have proposed other wild species as the progenitors of the crops (John Macbride got it right). But with hundreds of forms of Erythroxylum growing in the American tropics, confidence in any hypothesis rests on a solid characterization and analysis of the full diversity of this plant family across Central and South America; a goal that botanists have been working towards for centuries.

While numerous new Erythroxylum species remain to be described in South America—and conversely, several species names need revision because they refer to the same plant—our scientific understanding of the coca family has made significant strides. This progress has been built upon the careful study of the tens of thousands of Erythroxylum specimens collected by botanists over the past four centuries and preserved in herbaria worldwide. The foundation for global species synthesis was laid by Otto von Schulz in 1907, and then Timothy Plowman was responsible for the next most significant advancements. Yet much collection, research, and synthesis remain, particularly in diversity ‘darkspots’ like Madagascar.

As Plowman was digesting the global diversity of Erythroxylum and refining his ideas on the diversity and origins of coca, he and Francisco Schunke Vigo collected what they and locals called coca del monte, or ‘wild coca’ in the Huánuco and San Martín areas of the Peruvian Yungas. They were convinced this population of plants evidenced a true wild form of Erythroxylum coca var. coca, and the original wild plants ancient humans domesticated and then shaped into all four of the modern crops!

The death of Timothy Plowman in 1989 was a tremendous loss for the scientific community. His contributions to our knowledge of coca as well as Yesterday-Today-and-Tomorrow plants (genus Brunfelsia) were monumental.

Plowman died right before biologists began using DNA to understand species relationships. Our genealogical methods to build blueprints of the tree of life have since become fundamental tools in nearly all fields of biology. When I began my PhD research on coca in 2012, testing Plowmans wild coca hypothesis was one of my primary research objectives. So I studied herbarium collections in the US and abroad and collected Erythroxylum plants in South America to build DNA libraries and study the genealogy of the majority of species in the coca family.

The DNA revealed an amazing new picture of the ancestor of the coca crops and the origins of domestication of the crops themselves.

Multiple, ancient origins of coca

It turns out that Plowman and Schunke’s coca del monte is actually a form of Erythroxylum gracilipes (gra-silla-pees), a widespread and variable wild species that grows throughout the western Amazon and Guiana Shield. My genetic analysis, published in Systematic Biology in 2021, shows that E. gracilipes is a complex species with many distinct populations across its vast geographic range. Most fascinating, however, is that the coca crops form three different lineages nested within separate branches of the evolutionary tree of E. gracilipes. This indicates that there were, in fact, three independent domestications of coca.

One domestication occurred in northwestern South America, giving rise to the ancestor of tupa and hayo, which later became distinct varieties, possibly due to geographic separation between Peru and Colombia. This lineage was certainly abundant in Ecuador, but unfortunately, eradication efforts—beginning with Spanish colonization—have been largely successful there. Today, only a few scattered crops and a handful of herbarium specimens remain in Ecuador. Yet, these remnants are proving to be highly valuable for ongoing research.

A second domestication event occurred somewhere in the Yungas region, leading to the development of the coca variety. Interestingly, a few samples of E. gracilipes from southern Peru grouped with the coca lineage, which could indicate that this region was the original area of domestication. Alternatively, it could suggest hybridization with E. gracilipes. I am currently conducting additional tests to resolve this question.

The third domestication event likely occurred in the western Amazon, resulting in the ipadu variety. The similarity of coca-related customs and the genetic proximity of the ipadu lineage to western Amazonian E. gracilipes suggest that this is the most recent domestication event.

This remarkable discovery of three independent domestication events from a single wild ancestor species is unique among crop plants, whether in the tropics or temperate zones. Each domestication adapted the plant to local needs, shaping it to meet both human cultural preferences and environmental demands. These adaptations produced distinct lineages tailored to specific environments and cultural practices.

Adding to this narrative of extraordinary adaptation and ingenuity is another groundbreaking discovery: tupa-like coca leaves excavated from an archaeological site in northern Peru were found to be 8,000 years old. This site, analyzed by Tom Dillehay and colleagues, also yielded llipta samples that were radiometrically dated to 9,000 years ago. Together, these findings position coca as one of the oldest cultivated crops in the Americas.

Building on the foundational work of past pioneers and continuing the meticulous efforts of classical fieldwork, modern botanical and archaeological science has revealed that, within the last 10,000 years, multiple cultures in different regions of South America independently transformed the same natural resource—the wild Erythroxylum gracilipes—into an even more versatile and indispensable stimulant and medicine.

The journey forward

Coca’s story is one of resilience, innovation, and profound cultural significance. For over 9,000 years, the plant has played an indispensable role in the lives of many Indigenous peoples across South America, evolving from a wild species, Erythroxylum gracilipes, into a crop of extraordinary utility and versatility. The discovery of three independent domestication events highlights the remarkable ingenuity of ancient cultures, each transforming the same natural resource to produce a quotidian supplement and medicine.

This, together with the ancient archaeological evidence of coca use, underscore coca’s centrality not only as a stimulant and medicine but also as an ancient cultural and spiritual cornerstone.

Building on the pioneering work of figures like Timothy Plowman and Alexander von Humboldt, the scientific exploration of coca crops has entered a new era of discovery. While more questions than answers remain, interdisciplinary research is uncovering the evolutionary origins of coca and its profound cultural significance. These efforts aim to provide a clearer, more nuanced understanding of this iconic plant and its place in human history.

Coca’s legacy reminds us that plants are more than biological entities—they are living symbols of human history, adaptation, and cultural identity. By recognizing the complexity and depth of coca’s story, we are better equipped to engage in global conversations that respect and honor the traditions it represents, while moving toward a more just and informed perspective on its use and significance.