THERE IS A MORBID THRILL IN searching for the last of something. I considered this while looking for the critically endangered cactus Uebelmannia buiningii among the quartz hills of the Serra Negra in Minas Gerais, Brazil. Uebelmannia is a small genus of Brazilian cactus described by Dutch botanist Alfred Buining. The genus is named for the Swiss cactus collector and former race car driver Werner J. Uebelmann, a lifelong collector, nurseryman, and devotee of Brazilian cacti. These Eurocentric tendencies in species naming are common in botany, a field whose entwinement with settler colonialism and imperialism runs deep.

I was travelling with a group of self-described European “cactoexplorers” for several weeks through the states of Minas Gerais and Bahia, Brazil, a region with some of the highest cactus species richness and endemism in the world. I was invited to join the search as part of the research for my book on the global illicit trade in cactus and succulent plants.

Thanks to our guide, an expert Brazilian botanist, we were equipped with the precise coordinates of one of the few known locations of U. buiningii, so our prospects for seeing it were high. (On account of my research’s entanglement with questions of illegality and illicitness, I cannot disclose the real names of our guide or the men with whom I traveled.)

Unlike other species I had already encountered in Brazil, U. buiningii isn’t primarily threatened by farmland development or urbanization. According to species experts it is threatened above all by illegal collection for international trade. U. buiningii’s habitat is restricted to an area of less than 40 square kilometers, with just a few small and isolated subpopulations remaining. The type locality for the species, or the location where a plant was first taken and used to formally describe the species on an archived herbarium sheet, is now absent any remaining plants.

We had already driven well over a hundred miles down winding dirt roads, through a mountainous and forested landscape interspersed with eucalyptus plantations (for charcoal production), small cattle ranches, and agricultural fields, on our way to see other Uebelmannia populations. For several hours, our group made intermittent stops to scan the slopes of hillsides that might be home to unrecorded populations of known Uebelmannia species, or perhaps even a new species of the genus. As we scouted the landscape, we looked out for the presence of quartzite (the genus’s preferred growing substrate), as well as known companion species, including Pilosocereus aurisetus, better known as the hairy torch cactus. After several hours of failing to identify anything resembling what might be a new kind of Uebelmannia, we drove on toward the known coordinates for U. buiningii kept by our guide.

The thrill of seeing something truly rare was soon replaced by the forlorn
prospects that we were instead bearing witness to the extinction of a species.

Along the way, I spoke with two members of the group about U. buiningii, extinction, and the ethics of collection. “I think these are going to be ex-populations in a few years,” one of the collectors, a Belgian man, said. I responded by delicately bringing up that our guide had said illegal collection was the driving force behind their march toward extinction. “Well, that is what he says he thinks is the cause. But I think most people are aware now you shouldn’t collect plants from the wild anymore,” he replied. I refrained from mentioning several recent incidents involving European and American collectors caught with hundreds of live plants in their luggage while attempting to illegally transport regulated plants across international borders.

We eventually arrived at another slope covered in quartzite and inhabited by thousands of hairy torch cacti, possible indicators of U. buiningii’s presence. The palette of the landscape was dusty greens and muted whites and gray; it mirrored the lichen coating the quartz surface of the hill, complementing the hairy cacti with their understated blue-green hues and wisps of cornsilk hair. We searched for over an hour, everyone weaving slow paths in and around the protrusions of quartz outcrops and clumps of cacti, but to no avail.

As our group continued to search for U. buiningii in vain, a botanist and a Dutch collector talked while surveying the valley and hillside opposite us. “I was here 20 years ago,” the botanist, who was our guide, explained. “We came here with the farmer who lives over there [pointing to the slope opposite]. And back then we found some one hundred plants. And now there are none that we can see, with six of us looking for an hour.” He shook his head, resigned. I asked him what he thought was the cause of their absence. “Overcollection,” he said firmly. “There is a tipping point, where there are too few individuals left. Maybe there are still seeds in the seedbed, but maybe there weren’t enough to maintain a population, and maybe it is just gone.”

The anticipated thrill of seeing something truly rare was soon replaced by the forlorn prospects that we were instead bearing witness to the extinction of a species, an entire genealogy of life millions of years in the making. I asked our guide if it was still worth looking for a bit longer, and he suggested I look below the walking path that cut across the hillside. “Well, there has got to at least be one plant here,” the Dutch collector exclaimed with a sigh. Just as I headed toward the path below, a color caught my attention amid the washed-out landscape, a tiny blotch of muted purple haloed in white. “Is that one?” I asked excitedly. Though I had not seen the species before, I was sure this was the genus; several days spent scouring the ground for other Uebelmannia attuned my eye to the look of the plant. The botanist and Dutch collector rushed over to confirm that I had found it. My field notebook captures the experience’s immediate effect on me:

It felt exactly like the time I found my first morel mushroom alone in the woods. This upwelling elation. A leap of the heart, a warming sensation around the stomach. I felt overjoyed. We had all just accepted that the plant was likely locally extinct here, one of just a couple of known populations of the entire species. And here it was. Honestly, I nearly started to cry.

The search for the cactus left it with an overdetermined status in my mind, as something imbued with multiple and contradictory kinds of signification: desire and lack, extinction and care, of wanting something badly and yet realizing the seeing was tied to collection, the cause of this plant’s unmaking. In its overdetermination, it became an object of greater unconscious import. Although I witnessed a variety of ways cactus collectors seek enjoyment during cactoexplorations, I had not, until this moment in Brazil, experienced in affective registers the kinds of emergent person–plant relationships structured through awe that I had heard others relate and recount to me.

As the intensity of experience subsided, I took photos of the cactus alongside everyone else. I received several friendly slaps on the back for finding the plant. The Dutch collector announced that at a minimum, it made the day, and maybe the whole trip. After crowding around to take photos, we spread out to look for more plants, revitalized despite the heat. But after another 30 minutes, we still hadn’t found another. Our guide noted no sign of reproduction around it, no small offspring nearby, no offsets, no flower, no fruit. The species was going extinct, he explained; functionally, it likely already was.

While others continued to look with declining interest, I sat with the Dutch collector and our guide by the newly found cactus. “The strange psychology of collectors in this hobby is that some people would say now, ‘OK, this is the last one, and we should take it home, to protect it.’ Plenty of people would say that,” the collector said. The Brazilian guide nodded in agreement. The Dutchman continued, “I think we should be proud of our strength and courage in not doing this. I mean, you can also just buy this plant in Holland if you really want it!”

In the end, we found only the one cactus on the hill.

PEOPLE THE WORLD OVER utilize and consume countless species as part of everyday life. But on the much narrower list of species that people desire as living companions — dogs and cats, monsteras and aloes, birds and reptiles — few species are so easy to illicitly grasp, so lootable, as many cactus and succulent plants.

Scientists include approximately 12,000 species of plants in the category of “succulents.” Succulents are not a formal plant group, however, and they are found across a wide range of taxonomic orders, meaning the adaptation for succulent living evolved independently across the vegetal tree of life. Though disagreement exists, we can say a succulent is a plant that possesses specialized tissue that offers temporary storage of water, enabling it to be “temporarily independent” from an external water supply and maintain metabolic activity when roots are no longer able to obtain water. So, although all cacti fit this general succulent description, not all succulents are cacti.

Over 75 percent of all cacti are experiencing population declines globally.

The lootability of succulent life tells us something about how a plant’s adaptive strategies for survival might grip human desires. The live and illegal shipment of a baby tiger or parrot is not so amenable to the kind of transit to which many succulents are subjected. Lootability signals not only the capacity of certain succulents to survive theft but how the capacity to do so may constitute part of their enticement as objects of desire and the pleasure found in the taking.

Succulents are some of the most heavily threatened species among internationally traded plants for ornamental collection. A variety of species in the Dudelya, Aztekium, and Ariocarpus genera in North America, alongside Conophytum and Lithops in southern Africa (to name just a few examples), currently face intense illegal-collecting pressure, and some face pressing extinction concerns. Over 75 percent of all cacti are experiencing population declines globally, and about one-third of all approximately 1,500 cactus species are threatened with extinction. This makes cacti one of the most threatened taxa of life on the planet — inclusive of animals.

Nearly half of these threatened species are harvested for horticulture and private ornamental collections. Climate change paints an even bleaker picture for many of these species. The world regions with high succulent biodiversity and those expected to be most vulnerable to the impacts of climate change map tightly to one another. For all the global recognition succulents receive as charismatic species, many face very precarious futures.

Over the past seven years, my research into how people care for succulents has demonstrated that care for the nonhuman living world can look like many things. I have found that care and commodification are deeply connected with both illicit species collection and wildlife conservation and that the two are not necessarily antithetical practices. I believe they should be understood as rooted in shared human experiences, desires, fantasies, and anxieties that continue to shape the fate of much of the nonhuman world.

Care for species is often political, and its presence across the tree of life is remarkably uneven. Efforts to care frequently entail harm. To care for other species is messy, and in the fight against species extinction caused by the illegal wildlife trade, neat stories of heroes and villains fail to capture the place of desire in structuring the course of care, its recipients, and possibilities for species flourishing.

THE DAY BEFORE my encounter with U. buiningii, I stood with the Dutchman on an outcrop of rock overlooking a beautiful vista of flourishing cacti. He explained that one of the reasons these trips were so important was that other people would likely revisit our collective travelogues for years to come. This was not a wholly unreasonable comment, as he is well-known in the collecting community for giving engaging talks about his travels abroad. But it was also clear that, in his mind, the recording of our presence in these landscapes was part of an important effort to satisfy the desire to inscribe the self in the landscape.

In visiting and recording the stories of our travels and the plants we had seen (and not seen), it was as if we had signed a visitors’ log of the who’s who of cactus history. “We are literally following in the footsteps of Ritter,” he explained, referencing Friedrich Ritter, the famous twentieth-century German cactus expert (and Nazi, I feel compelled to share), who extensively surveyed Brazil and other South American countries for cacti. “I think that is quite exciting. And it’s exciting to think that in the future, next generations might say the same things about us.” There was a silence between us for a minute as we both scanned the gorgeous scenery. “It really gives you the feeling of living on a planet where there are still things to discover — and you are empowered to discover them,” he added.

The Dutchman’s response to my U. buiningii spotting the next day — that so many other collectors might have felt the urge to take the last of the species to protect it — seemed like an extension of this line of thought. There was a deeply imperialist sentiment that clung to this description of powerful urges to possess, extract, and protect in geographies marked by colonialism. It also felt steeped in familiar contradictions about who does conservation work (i.e., White Anglo-Europeans with savior complexes), where it ought to be done (the Global South), and what remained unspoken about the forces driving species loss at the global scale. These are the uneven dynamics so often embedded and reproduced within protectionist conservation discourses. Yet they were also the same dynamics I repeatedly heard articulated by European collectors describing cacti as being “better off” in their greenhouses than left in the countries they came from.

There is a remarkable symmetry in thought between old-guard conservation thinking and possessive desires of collectors, even if conservationists may balk at the suggestion. But as numerous studies of protected areas demonstrate, exclusionary conservation management — which so often has involved the dispossession of traditional and Indigenous stewards of the land — is also the expression of possessive desires to covet the Other, simply by another name and at a more ambitious scale.

My time with cacti and collectors also highlighted how difference is linked to desire.

My time with cacti and collectors also highlighted how difference is linked to desire. After visiting U. buiningii, I speculated on what its fate might have been had it been known differently, perhaps not as a species but as a subspecies of another Uebelmannia. If U. buiningii was not categorized as its own species, would this form of species “lumping” potentially offer it a greater degree of protection from those who seek complete collections of the genus? Or would this possibly only make it more vulnerable, as endangered species legislation might not apply to it if this larger species category were now of a sufficient size to disqualify it from endangered status? These productions of botanical difference, the work of “splitting” or “lumping” by enthusiastic collectors, botanists, or cactoexplorers who desire to “discover” or name something new, have material consequences for the plants we come to know as species.

Uebelmannia is a genus that has undergone a variety of revisions in species names since it was first described as a genus in the 1960s by Alfred Buining, who was assisted in the field by Leopoldo Horst, the founder of a major cactus nursery (still open today), in the Brazilian state of Rio Grande do Sul. These trips to describe and collect new species in the mid-twentieth century were funded by Werner Uebelmann, with the intention that newly described species could be sent to his Swiss nursery (which he operated until the 1980s), where he would, for a time, hold a veritable monopoly on the sale of these new cacti species.

It is rumored that on these expeditions, Buining would pay Horst a bonus for newly described species. In time, several previously identified Uebelmannia “species” would later be recategorized as “subspecies” or “variations” within larger species “groups” or “complexes.” These nonspecific terms tilt at the messiness of vegetal life that make clear delineations of difference in the world of plants quite difficult in taxonomic terms. In this way, the three men all profited through producing difference. Buining’s botanical reputation increased as he continued to describe new species, and Horst and Uebelmann both profited from these formal descriptions, which served as scientific support for new species they could then sell to collectors hungry for novelty.

“It’s quite interesting to look at the intentions of describing authorities in naming things,” the Dutch collector said one day while we were out searching in the field for more Uebelmannia. Not one to shy away from provocation, he then added knowingly, “But you have to question the naming and motivation for identifying difference.” He was gesturing at explicitly profiting by promiscuously naming “novel species,” which taps collectors’ desires to “complete” their groups with “missing” plant species, (for example by procuring every species in the genus). Manufacturing more distinct species means there are more to sell. As a Czech botanist would later explain to me, “There are some people who put new names [on species]; if you have a new name in a catalog, it’s a best seller, and the personal motive to have your name on a new species [is there]. So those are private interests, to be famous, to be rich.”

Such stories of entrepreneurial cactus enthusiasts profiting from the “discovery” of new species that in time are discredited or reshuffled by botanists are common. I was more surprised, however, to learn how contested the species concept is in the world of botany. As one botanist put it, “The species concept doesn’t always work so well for many plants in terms of what matters for conservation. As a botanist, the species concept doesn’t work very well in general, and it doesn’t work well for many cacti.” Another botanist noted that plants are formally recognized and protected by endangered species legislation only at the species level in Brazil (like most countries), so identification of unique forms or subspecies means nothing in the context of enforcement and legal protections. “I would name a new species even if I really knew it was just a subspecies or form,” he explained. “I would do it if it meant a type of plant in need of protection would receive it.”

OUR LAST DESTINATION for the day was a location that our guide said, based on satellite imagery, might represent a suitable habitat for U. buiningii but was one he had never visited. After arriving at the location, we searched for about an hour for signs of U. buiningii under an intense afternoon sun. Despite the presence of companion plants and quartzite, it appeared we would turn up empty-handed. Then a member of the group gave a shout and said he spotted one, a very small U. buiningii with a brilliant, deep reddish color. As we gathered around to see it, our guide quickly spotted four nearby. This was a new population that wasn’t yet recorded by collectors or scientists as far as our guide was aware. We eventually found 30 to 40 small plants, many almost completely embedded within the quartz sand. “They are a small and hidden plant,” our guide mused to himself as we inspected the ground. That there could be so many more just hiding beneath the surface was a welcome thought.

As we prepared to leave, I asked our guide if he was going to take a specimen of this population to send to an herbarium, to formally record the presence of the new locality. “I think it is best if we leave it unknown for its conservation,” he replied.

In the complicated business of saving species, that leaving these plants unregistered represented doing conservation work to the botanist was a matter of cold pragmatism. Avid collectors are also often dogged researchers; if the location of this tiny U. buiningii population were registered in a database with geographic data, the locality could become vulnerable. But if it is not registered, the population will likely not be monitored (formally, at least), or considered in future species assessments, to say nothing of being excluded from scientific research. In displacing this local population of U. buiningii from the realm of scientific concern, the guide saw his intentional exclusion of the species as an act of care.

I was unsettled by the thought that collector desires left conservationists so poorly equipped to care for the species in a manner that might point towards awareness and action instead of obscurity and obfuscation. Only time will tell if our guide was correct about what it means to care well for this species. But his decision also raises the question of how we will ever know, given disclosing the location of rare plants is loaded with so much risk.

The next day, as we were out on yet another cactus hunt, he stopped and turned to me. “I haven’t taken you to several places where there used to be populations of plants, because now there is nothing to see,” he said. Then he shook his head and walked on, his eyes scanning the ground on the lookout for another kind of cactus.

This article is adapted from his new book, The Cactus Hunters: Desire and Extinction in the Illicit Succulent Trade, to be published by the University of Minnesota Press in November, 2023.