Victorian Botany: Conservatories

This series of posts is on plants and plant technologies that were popular in Victorian Britain and its spheres of influence, which means just about everywhere.  What started me on this topic was coming upon several books that fitted the theme including Kate Teltscher’s (2020) Palace of Palms: Tropical Dreams and the Making of Kew.  It deals with the transformation of the Royal Botanic Gardens, Kew from a failing establishment to the hub of a horticulture empire in the mid-19th century.  She begins with the botanical politics involved in rescuing Kew in the 1830s.  At that point it was composed of 11 acres that abutted the much larger Royal Pleasure Grounds.  It was directed by William Aiton who had been there for years and who wouldn’t share plants with other botanical gardens and even refused to label plants after several prized specimens had been stolen. 

It seemed to many that Kew was not worth saving, but there was push back and a commission was formed to investigate the situation.  It was comprised of John Lindley from the Royal Horticultural Society, Joseph Paxton gardener for the Duke of Devonshire, and John Wilson, gardener for the Earl of Surrey.  While the first two were well-known and respected in botanical and horticultural circles, Wilson was a political appointee.  With much behind-the-scenes maneuvering, the commission recommended that the garden be saved and converted from royal to governmental control.  The next step was finding someone to direct it, with Aiton staying on as director of the pleasure grounds.  Lindley wanted the job, but it ultimately went to William Jackson Hooker, professor of botany at the University of Glasgow.  He brought with him a library and a herbarium of over a million specimens, the largest in Britain at the time.

Teltscher does a great job of describing how Hooker set about improving Kew’s reputation in the botanical and horticultural communities.  He sent John Smith, the curator of living collections, on a tour of gardens throughout the United Kingdom to learn about novel practices, pick up design ideas, and let it be known that Kew was interested in sharing its duplicate stock with gardens that could reciprocate.  Smith returned with a feeling of accomplishment and a greater willingness to work with Hooker, who had gotten the job Smith  thought he should have.  Relatively early in this new regime, plans began for a new palm house, since Kew’s palms were pushing through the roof of their greenhouse.  A new glass and iron conservatory was modeled on the one that Paxton had designed for the Duke of Devonshire’s estate at Chatsworth.  I had known of Paxton’s involvement, but I knew nothing of the role played by Richard Turner, an engineer with a foundry in Dublin.  He devised a new type of iron framework for the glass panes and also designed a heating and ventilation system.  Just as in describing Kew’s rescue, Teltscher is good at laying out the intricacies involved in building this massive structure that covered over half an acre.

When the Palm House was completed in 1848, it fell to Smith to fill the vast space.  Massive palms had to be moved from their old venue and from several other greenhouses.  Still, this left the side aisles bare in the early days, as fast-growing species were nurtured in the emptied structures.  However, the public was thrilled with what they saw, and visitors to Kew increased as did its reputation in horticultural circles.  The garden now had a focal point, a symbol of its botanical wealth and reputation.  Meanwhile, Hooker was building the garden in other ways.  Aiton had retired in 1845 and Hooker was given control over the pleasure grounds, which meant that Kew had grown from 11 acres to over 200.  Plant exchanges continued to enrich the garden’s variety of plants, as Kew was encouraging donations not only from other botanic gardens but from those who traveled widely.  Hooker also maintained correspondence with botanists and plant collectors who sent him specimens from around the world.  Vast collections came from botanists working in gardens in India, Australia, and other British colonies.  Kew became a hub for the global transfer of plants including, of course, palms. 

Palms were sources of fruits like dates and coconuts, as well as oil, building materials, and fiber for ropes, baskets, and even cloth.  Though Aiton had stored economic botany materials that Joseph Banks had sent to Kew as evidence of the financial potential of exotic species, the materials had never been organized or catalogued until John Smith employed his son to do the job.  Eventually Alexander Smith became curator of the collection and in charge of the Museum of Vegetable Products opened in 1847.  This was soon renamed the Museum of Economic Botany and eventually grew to spread over four buildings in its heyday (Nesbitt & Cornish, 2016). 

Despite all this garden administration, Hooker still found time to continue his studies on ferns and produce a multi-volume work.  In addition, he nurtured the botanical career of his son, Joseph Dalton Hooker.  The Hooker family was not wealthy, so Joseph had to earn a living.  His father engineered his appointment to an expedition to India, and later Joseph became assistant director at Kew.  At his father’s death, Joseph was named director, and after some negotiations, William Hooker’s herbarium and library were sold to Kew, thus providing Joseph with a modest inheritance and Kew with solid scientific resources.  This is essentially where Teltscher’s story ends, though Kew continued to move from strength to strength, always with the Palm House as its symbol.

Reference

Teltscher, K. (2020). The Palace of Palms: Tropical Dreams and the Making of Kew. London: Picador.

Using Biodiversity

Seed collection at the herbarium, Penn State University

To continue with the discussion of the Global Strategy for Plant Conservation (GSPC) targets from the last post, they deal with not only conserving plant species, but using them.  The rising human population exacerbates environmental problems and the demand for resources.  Sustainability is a term that suggests a solution:  employing resources in a way that can be stably continued over time and relying on resources that can be stably renewed.  Many themes come into play in this effort from saving seeds to using plants’ genetic diversity and the rich plant knowledge base of indigenous peoples. 

Seeds have always been of interest to botanists; they are an easy way to transport and share plants.  Luca Ghini did not just create one of the first herbaria, he also kept a catalogue of the seeds he collected from plants at the botanical garden of Pisa he founded.  He sent the list to other botanists and offered them seeds of any listed species.  However, seed saving was going on long before that.  Farmers kept seed to plant the next year’s crops, taking those from the best performing plants, thus selectively breeding for particular traits.

As agriculture scaled up and became more mechanized, a different model developed, with farmers buying seed from companies that grew plants for seeds, often with limited genetic variation.  Recently, seeds for many crops are from genetically engineered plants with traits like increased nutrient levels, resistance to pests, or faster growth.  Using these seeds decreases genetic variation in crop plants, with resulting susceptibility to pathogens.  With greater genetic diversity, at least a portion of the plants would survive.  Some farmers and gardeners have saved seed from what are called heirloom varieties or landraces, strains that were developed to grow well in particular areas, rather than being mass-produced.  These growers were doing a service to the larger community by conserving and propagating biodiversity and are now more appreciated. 

Many herbaria have seed collections; they were popular early in the century, and were often sold in custom-made cases, with each seed type in a small labeled vial.  These samples were not meant for propagation—seeds usually lose their viability rather quickly.  Instead, the seeds aided in identifying species that might have been collected with seeds.  In most cases the seeds are so old that they will not germinate, though they can be a source of DNA.  Seedbanks, on the other hand, are designed to save seed for future planting and some are of long standing.  They are crucial in preserving genetic diversity of crop plants and their wild relatives, and also of plant biodiversity in general.  Many nations have seeds banks, especially for agricultural crops and also for horticulturally important species.  The Russian botanist Nikolai Vavilov created an early bank for the many seeds he collected during his surveys of regions where various crop plants had originated.  The massive Svalbard Global Seed Bank built into permafrost within the Arctic Circle focuses on crop species, their wild relatives, and landraces.  It was created as a backup facility for seed collections throughout the world, in case any suffer damage.  The largest seed repository is the Millennium Seed Bank managed by Kew that aims to store seed for as many wild plant species as possible extending beyond the useful.

At the Max Planck Institute for Plant Breeding Research, the Ross Potato Herbarium was founded after its namesake collected specimens as well as seed potatoes in South America in 1959, and it grew as additional material was added.  The USDA has a number of facilities for germplasm (seeds, cuttings, and plant tissue) throughout the country, and the National Arboretum in Washington, DC hosts the USDA’s herbarium.  In the United States, many crop-related specimens are housed in the institutions that grew out of the nineteenth-century land grant colleges.  These herbaria often have large collections of cultivated plant specimens because of their strong horticulture and agriculture programs.  The University of California, Davis is known for these, and being in California, it had a viticultural herbarium of grape vine specimens that has now been incorporated into the general herbarium. 

Some herbaria, particularly those with ties to indigenous peoples and to the high-diversity areas where many reside can be particularly focused on species that have agricultural and medicinal uses.  These communities are also the source for many plant varieties that are now of interest because they are landraces grown for generations and are outside of the agricultural-industrial complex.  It makes sense that if biodiversity is important for sustainable agriculture, then focus needs to be put on working with local communities, as has been done for many years in collecting potato varieties in the Andes for the International Potato Center in Lima, Peru.  This center and others around the world that focus on specific crops such as rice, wheat and corn not only store valuable genetic material but also do research on plant varieties with increased nutrients and other useful characteristics.  They also work with local populations in finding ways to make agriculture sustainable.  There are efforts to move away from concentrating on a single crop and create agricultural practices less damaging to soil and surrounding ecosystems.  Mixing crops including within forest environments instead of completely cutting down the trees are becoming more common initiatives and definitely in line with the GSPC. 

Conserving Biodiversity

One of the outgrowths of the Convention on Biological Diversity (CBD) discussed in the last post was the Global Strategy for Plant Conservation (GSPC) of 2002.  Updated 10 years ago, it has five objectives and within them 16 goals or targets.  While not all the targets have been met, there has been a great deal of work done toward them, and herbaria have been at the forefront of these efforts as have botanic gardens.  In fact, Botanic Gardens Conservation International, a global partnership, has taken a lead.  The first objective, not surprisingly was to understand plant diversity and one of the targets was an online flora of all known plants; this effort is headed by the Royal Botanic Gardens, Kew.  Though not complete, the flora does include information on each listed species’ range, with related literature and a sampling of illustrations and herbarium specimens.

Another target was to determine, “as far as possible,” the conservation status of all known plants.  This goal is much more difficult to achieve, but the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species established in 1964 is the most comprehensive inventory of species vulnerability worldwide.  Those with economic or cultural value, and those most apparent to humans, are more likely to be included because a great deal of work goes into getting a species listed, and delisted if its status improves.  In the case of plants, evaluation includes research in herbarium collections to determine a plant’s range in the past compared to what it is now, and at times to clarify precisely what species is being listed.  To put teeth into the protection of species on the Red List, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) was presented at a Washington, DC meeting in 1973.  It controls commerce in endangered species and comes into play in botany especially with illicit trade in timber from rare trees and exotic plants such as orchids and cacti. 

About a third of the world’s plants are threatened with extinction.  Such loss could be comparable to some earlier mass extinctions including the one about 65 million years ago that brought the age of dinosaurs to an end.  But it was not just dinosaurs that disappeared, that’s not the way the living world works.  Species are so interdependent that a single extinction can result in greater loss:  the species’ parasites and predators could also suffer population crashes leading to extinction.  That’s why conservationists focus on protecting habitats and ecosystems, not individual species such as a beautiful orchid or bird.  Species that catch the human eye are linked to many others such as microscopic invertebrates and fungi that are less obvious but equally important.

The goals of the second GSPC objective are more multispecies in scope including conserving 15% of each ecological region or vegetation type and 75% of the most diverse areas, the biodiversity hotspots.  Other goals include growing 75% of threatened plant species in situ, that is, in their natural habitat and also ex situ in botanical gardens or other protected areas, preferably in the plant’s home country.  This last goal highlights the importance of botanic gardens in biodiversity conservation.  They have become safe havens for many species, places where plants can be cultivated and propagated.  In a sense, this is an outgrowth of the mission of nineteenth-century colonial botanic gardens and their mother gardens in Europe, such as Kew in London and the Jardin des Plantes in Paris.  Now there are more gardens in plants’ home countries and under the supervision of the countries’ own people, who, thanks to the CBD, can make binding decisions about how these plants will be distributed and used, including for ecosystem restoration projects.  However, the resources of gardens in developed countries are still necessary; they nurture plants on site, also sending them back to the country of origin, with the goal of having 20% of the plants available for restoration work.

In addition, botanical gardens preserve specimens to document what is grown and some saving small samples of plant material under ultra-cold conditions for future use in DNA sequencing studies.  Ideally, each sample is associated with a herbarium specimen voucher for reference.  Just as herbaria were important to economic botany in the nineteenth century, they are crucial to biodiversity research in the twenty-first.  The number of herbaria in developing nations has increased substantially in this century and the number of specimens housed is rising at an even faster pace, in part with the impetus of the GSPC.  The best resource for tracking herbaria and their growth is the annual report of the online Index Herbariorum, the definitive guide to the location and holdings of the world’s herbaria.

The GSPC’s third objective is for plant diversity to be used in a sustainable and equitable manner.  This depends on support from herbaria and from the international community in the form of the CITES treaty to prevent trade in endangered species.  Because of economic deprivation in many developing countries, there is great pressure to profit from natural resources, including plants and animals.  Uprooting rare plants does more than just reduce the population, it damages the entire habitat and makes it less likely that the plants can grow back.  Herbaria play a role in, for example, providing evidence in court cases arising from the seizure of endangered plants.  Taxonomists may be called on to verify that the species is in fact on the Red List.  The same is true of illegal trade in timber from endangered tree species, with xylarium collections’ wood samples compared to recovered timber.  CITES does have a downside as far as herbaria are concerned in terms of shipping specimens internationally.  There are forms that have to be filled out to certify that the material is only for research purposes and not for profit.  At times the red tape can be excessive, making the work of herbarium managers frustrating.

Protecting Biodiversity

Map of New Guinea

A prime reason for learning about biodiversity (see last post) is to find ways to conserve it.  One approach was developed at a meeting in Rio de Janeiro in 1993 and led to the Convention on Biological Diversity (CBD) that gives each nation sovereignty over its biological wealth.  It aims to prevent developed nations from continuing to exploit the biota of developing nations, most of which had their progress thwarted by centuries of colonial rule.  The CBD represents a major shift in how the biological resources of a country are seen not only economically, but politically and culturally.  For example, the cinchona tree, native to Andean rainforests, is considered not only as the source of a valuable commodity, quinine, but as a resource growing in a particular place and therefore subject to the regulations of the government of that place.  Cinchona also has a long cultural history; it was Andeans who originally discovered its fever-relieving effects centuries ago and this plant has been documented with herbarium specimens, seeds, and also in poetry and art.  It is an integral part of Andean heritage, though it now grows in plantations around the world (Crawford, 2016).

Cultural connections can be found for thousands of plants worldwide, but economic and political issues often are at the fore when it comes to plant collecting.  Since the ratification of the CBD by most of the world’s nations, these issues have had a significant effect on botany, and on herbaria, just as they have had throughout the history of botany.  The difference now is the aim of equitable distribution of value.  Even non-signatory nations must comply with the procedures set down by those that have signed if they want to be allowed to collect, so this and the other international agreements have had a significant impact on how the biological wealth of nations is viewed and treated.  This is especially true since ratification of another UN-sponsored document, the Nagoya Protocol, a 2011 agreement that grew out of the CBD. It deals with the genetic resources of plants and animals, and how their benefits can be shared and used fairly and equitably.  It aims to prevent exploitation of resources, for example, by drug companies collecting plants that have medicinal uses and then developing drugs based on these plants in the companies’ laboratories without sharing profits with the country where the plant was collected and with the people who revealed its medical efficacy.

The Nagoya Protocol gives the host country the right to set strict limits not only on what can and cannot be collected, but also on how it can and cannot be used after collection.  Restrictions along with those of the CBD are meant to prevent the kind of exploitation by wealthy nations carried out for centuries, so they are attempting to right grievous wrongs.  A botanist who wishes to collect in another country must obtain a permit, or a series of permits, to do so.  These delineate what can and cannot be gathered, often only specific plant groups and in specific quantities.  Travel might also be limited to particular geographic areas.  Where possible, unless the plant is very rare, it is collected in multiples, and specimens are retained in an institution in the host country as well as in the collector’s institution. 

Requirements and procedures vary widely from country to country, and it may take months if not years to obtain necessary documents, which in some case are issued across multiple government agencies at levels going from country-wide to state, municipality, or other jurisdiction.  This sounds daunting, and it can be.  Some botanists and policy makers argue that the paperwork can be so difficult as to effectively prohibit or severely curtail collection and therefore hinder biodiversity research; requirements can have the opposite effect to what was intended.  The protocol does prevent exploitation, but in some cases it prevents research that might lead to practical benefits for the country in question.  In a commentary on a recent assessment of the biodiversity on the island of New Guinea, the authors noted that while half the island is part of Indonesia, a signatory to the protocol, the other half, Papua New Guinea, is not.  This is making the latter a more attractive location for biodiversity research (Novotny & Molem, 2020).

More mundane problems also persist.  Travel in many areas is difficult, as is transport and communications.  Shipments can get lost and may turn up eventually, or may be gone for good.  Australian customs officials destroyed type specimens sent from France over a mix-up about proper identification of the plant material (Davidson, 2017).  Restricting movement of plants into Australia is understandable.  These are definitely legitimate issues in preventing spread of invasive non-native species.  Australia, because of its remoteness, has a large number of endemic species and has suffered extinction of native plants and animals due to invasives.  But the invisibility of herbaria and their work has compounded the customs problem, since most nonscientists have never heard of herbaria and do not understand that specimens are dead, not living, plants. 

References

Crawford, M. J. (2016). The Andean Wonder Drug: Cinchona bark and imperial science in the Spanish Atlantic, 1630-1800. Pittsburgh: University of Pittsburgh Press.

Davidson, H. (2017, May 8). Australian biosecurity officials destroy plant samples from 19th-century France. Manchester Guardian.

Novotny, V., & Molem, K. (2020). An inventory of plants for the land of the unexpected. Nature, 584(7822), 531–533. https://doi.org/10.1038/d41586-020-02225-4

Cataloguing Biodiversity

This series of posts deals with threats to biodiversity from a botanical perspective.  There is no lack of evidence for climate change and it’s easy to become overwhelmed and pessimistic.  But the only way forward is to learn more about what is happening and why, and then to take action based on that knowledge.  One example of the botanical community’s efforts is a report published by the Royal Botanic Gardens, Kew, with contributions from a global roster of researchers.  State of the World’s Plants and Fungi 2020 is a useful blend of optimism and caution, presenting how biodiversity is catalogued, what is being learned about it, and how it can be preserved and also used into the future.  This latest report is supplemented with articles in a special issue of Plants, People, Planet as well as with a virtual symposium.  Earlier, Kew had published separate reports on plants and on fungi, but it made sense to combine them since this is how they are found in the world. 

It’s no surprise that Kew would have a leadership role in biodiversity research with its impressive staff and the world’s largest herbarium.  It also has a long history of studying plant diversity in developing nations, though granted, for a good portion of this history Kew’s efforts were on behalf of the world’s largest colonial power.  Garden administrators directed far-flung collectors, who relied on the expertise and labor of countless indigenous assistants and enslaved persons in finding plants that often proved economically important to the British (Brockway, 1979).  The past and future are intertwined at Kew in complex ways in its living and preserved plant collections.  Kew sponsored a symposium on the recent work of digitizing its collection of Miscellaneous Reports that colonial botanic gardens sent to Kew.  It is an important step in decolonizing its collection and was a fascinating look into how plants and plant products moved throughout the British Empire.

The present Kew report notes that 1942 new vascular plant species were described in 2019.  Many new finds were recently collected, but herbaria harbor plants awaiting identification and in some cases discovery as new species.  There is no solid estimate of the earth’s total plant diversity, of how many different plants exist.  The best record of known plants runs to around 350,000, with 325,000 of them flowering plants.  The situation with fungi is cloudier.  Almost 150,000 fungal species have been named and described; 1,886 were added in 2019.  With much research now being done on fungi, greater diversity is becoming apparent, and estimates of the number of fungal species now range from over two to nearly four million.  To me this is one of the most fascinating aspects of the report:  how the power of the fungal world is finally coming to be appreciated.  Two books that have done much for fungal publicity are Peter Wohlleben’s The Hidden Life of Trees (2016) on how fungi support plant life and Merlin Sheldrake’s Entangled Life (2020) on how fungi influence so much of the living world. 

The Kew report notes that the great biodiversity in tropical areas means some countries, though explored for centuries, are still yielding many discoveries.  Brazil, Madagascar, India, and South Africa have been collection areas from the sixteenth century on.  There have been a number of projects where these sites have been revisited, with older collections used in planning surveys.  The new work may recollect the same specimens, which can be used in genetic comparisons with the older plants.  Not finding some species points to changes in the habitat due to climate change or other factors, and not surprisingly there may be new species found as well.

Island ecosystems are particularly rich in endemic species found nowhere else:  83% of Madagascar’s 11,138 native plant species are limited to this island, making learning about and protecting its flora especially important.  A recent study in New Guinea reports that it has the world’s richest island flora with 13,634 species, 68% endemic (Cámara-Leret et al., 2020).  This is the first comprehensive plant list for the island, and the study could be a model for future work in other areas, though it may still be quite incomplete.  There are 3,962 tree species on the list, which seems impressive, but the number found in an inventory of the Amazon region was over 10,000.  In South America, researchers surveyed all the plants in almost 2000 study plots, a time-consuming and labor-intensive cataloguing job particularly under difficult conditions.  In New Guinea, only 300 plots were surveyed, which may explain the lower tree species count.  This suggests that discovering biodiversity is both hard work and not near its end, while these species-rich areas are under increasing threat from development (Novotny & Molem, 2020).

There are many factors involved in estimating biodiversity.  It is not just the density of sampling, but where the sampling is done.  Studies of the geographic locations on herbarium specimens has uncovered many collection biases because botanists, being human, tend to collect relatively close to home and even during exploration, find some areas easier to access than others.  For former colonies, the regions around botanic gardens were often well studied, or were along supply routes, or near seaports or other urban areas.  Species-rich regions of South Africa were explored from the 17th century (see image above), but there were no collections in some areas until the end of the 19th century when they were opened to agriculture (Cowell, 2020).  Few collections were made in highly diverse portions of Cameroon until they were surveyed over a decade beginning in 2004; 2240 plant species were found with about a tenth under threat of extinction (Demissew, 2015).

References

Brockway, L. B. (1979). Science and Colonial Expansion: The Role of the British Royal Botanic Gardens. Interdisciplinary Anthropology, 6(3), 449–465.

Cámara-Leret, R., Frodin, D. G., Adema, F., Anderson, C., Appelhans, M. S., Argent, G., Arias Guerrero, S., Ashton, P., Baker, W. J., Barfod, A. S., Barrington, D., Borosova, R., Bramley, G. L. C., Briggs, M., Buerki, S., Cahen, D., Callmander, M. W., Cheek, M., Chen, C.-W., … van Welzen, P. C. (2020). New Guinea has the world’s richest island flora. Nature, 584(7822), 579–583. https://doi.org/10.1038/s41586-020-2549-5

Cowell, C. R., Anderson, P. M. L., & Annecke, W. A. (2020). Historic herbarium specimens as biocultural assets: An examination of herbarium specimens and their in situ plant communities of the Agulhas National Park, South Africa. People and Nature, 2(2), 483–494. https://doi.org/10.1002/pan3.10087

Demissew, S., Beentje, H., Cheek, M., & Friis, I. (2015). Sub-Saharan botanical collections: Taxonomic research and impediments. In I. Friis & H. Balslev (Eds.), Tropical Plant Collections: Legacies from the Past? Essential Tools for the Future? (pp. 97–114). Stockholm: Scientia Danica.

Novotny, V., & Molem, K. (2020). An inventory of plants for the land of the unexpected. Nature, 584(7822), 531–533. https://doi.org/10.1038/d41586-020-02225-4

Sheldrake, M. (2020). Entangled Life. London: Bodley Head.

Wohlleben, P. (2016). The Hidden Life of Trees. London: Harper Collins.

Biocultural Ethnobotany

Cotton grown locally in Aiken, South Carolina

Ethnobotanical research has moved beyond just searching for medicinal plants or even food plants.  There is now a more holistic approach to indigenous plant knowledge, one tied not only to finding valuable plants but to saving biological and cultural diversity as well (Cámara-Leret & Bascompte, 2019).  This makes recording the vernacular names for plants important in field notes and even on herbarium sheets as a way to preserve knowledge.  From early in the history of plant exploration, such information has been unevenly respected, though as discussed in previous posts (1,2), some botanists were careful to record not only local names but uses for plants.  Ethnobotanists are now combing herbarium sheets and collecting journals kept in European and North American herbaria for leads in seeking out present-day knowledge held by local populations (Nabhan, 2016). 

This points to the fact that there is a significant gap between the botanical infrastructure of developed and developing nations.  Closing what in many cases is a chasm must involve more than just sending teams of experts to assist in plant collecting, and sponsoring students to attend graduate schools where large plant collections like those at Kew or NYBG are easily accessible.  The infrastructure needs to be developed where the plants are, and this is slowly happening, particularly in countries like Brazil and South Africa, where universities are educating botanists who will fill new academic positions and help to overcome the taxonomic impediment of a lack of professionals.  Assistants in the field are also being trained, with parataxonomists receiving instruction in collecting and in plant identification.  At last those who do the work of collecting are being treated as worthy of education and acknowledgment (Basset et al., 2004).  Visiting botanists can still provide valuable assistance, but they are often as likely to be learning from the permanent staff in local institutions as offering expertise.

Anthropologists and ethnobotanists working together have discovered a close link between extinction of species and extinction of local languages (Gorenflo et al., 2012).  Research shows that neighboring peoples who have different language traditions are unlikely to share plant knowledge, so with the death of a language comes an acute loss of learning.  Close observation going on for centuries has resulted in information on plant blooming and fruiting times, plant/animal interactions, and of course, a host of uses for plant material.  Indigenous expertise is invaluable and in many cases fading fast since younger generations are often less interested in traditions that might well lead the way forward in environmental conservation (Nabhan & St. Antoine, 1993).  Ethnobotanists today are helping to document this information with, among other things, herbarium vouchers, to anchor that knowledge to specific data about plants (Stepp & Thomas, 2010).

Throughout the world, herbarium collections are being formed by indigenous peoples to document the flora important to them—a way to preserve plants and the knowledge attached to them.  Two tribes in California are working with the University of California, Berkeley’s Jepsen Herbarium in making such collections, and the Newe people in Idaho have created a herbarium to document what grows on their lands.  These are manifestations of a desire to maintain their identity in a particularly important way, since plants provide so many of the resources that supported these groups and shaped their cultures.  These peoples were shaped by their ecosystems as much if not more than they shaped them, and specimens help to tell this story.

Learning about such projects and about how language, history, and ecology are woven together can also help those not part of such cultures to appreciate that they too are shaped by the plants they have relationships with.  Awareness of plant connections might generate some thought about how buying carrots in a plastic bag provides an impoverished experience of this vegetable.  If this is the only way someone sees carrots, they have no idea how beautiful their leaves and flowers are, or how good a fresh carrot tastes.  The fact that in the same country where carrots come in plastic bags, there are indigenous peoples preserving their biological heritage in herbaria, suggests how biocultural issues can vary greatly within a geographical area.  Looking at the culture of plant use across the board could make everyone more aware of how important plants are to our lives and spur finding better ways to appreciate our links to them.

In the United States, houseplant sales have increased significantly during the Covid pandemic.  So has cat and dog ownership, but let’s stick with the plants here.  In the 1980s, E.O. Wilson published Biophilia in which he argued that attraction to other species is an innate human trait.  For most of our species’ history, humans have lived intimately with nature.  It would be peculiar if we didn’t have adaptations as a result.  Also as a result of Covid there are more and more studies substantiating Wilson’s view:  time spent in natural settings improves mental health and increases a sense of wellbeing.  I can envision ethnobotanical studies, vouchered of course, that investigate how plants are used for what we term decorative purposes.  As someone who wrote an article on the biology of interior decorating (Flannery, 2005), I think this is a great idea.  What plants are sprouting in peoples’ homes?  Are they being grown from seed or purchased fully grown, in which case the ecology of big box stores and garden centers needs to be investigated.  And how long term are these plant-human cohabitations:  until the plant stops blooming, or loses all its leaves, or are they together for the long term?  Just as anthropology has broadened its focus and now investigates groups beyond the indigenous populations traditionally studied—for example, scientists—the same move would be helpful in ethnobotany (Lynch & Woolgar, 1990).  Since everyone uses plants, it would support the future of botany, and of society, to delve into the relationships of all people to plants, if for no other reason than to alleviate the problem of plant blindness.

References

Basset, Y., Novotny, V., Miller, S. E., Weiblen, G. D., Missa, O., & Stewart, A. J. A. (2004). Conservation and biological monitoring of tropical forests: The role of parataxonomists. Journal of Applied Ecology, 41(1), 163–174. https://doi.org/10.1111/j.1365-2664.2004.00878.x

Cámara-Leret, R., & Bascompte, J. (2019). Indigenous Knowledge Networks. The Ethnobotanical Assembly. https://www.tea-assembly.com/issues/2019/9/29/indigenous-knowledge-networks

Flannery, M. C. (2005). Jellyfish on the Ceiling and Deer in the Den: The Biology of Interior Decoration. Leonardo, 38(3), 239–244.

Gorenflo, L. J., Romaine, S., Mittermeier, R. A., & Walker-Painemilla, K. (2012). Co-occurrence of linguistic and biological diversity in biodiversity hotspots and high biodiversity wilderness areas. Proceedings of the National Academy of Sciences, 109(21), 8032–8037. https://doi.org/10.1073/pnas.1117511109

Lynch, M., & Woolgar, S. (1990). Representations of Scientific Practice. Cambridge, MA: MIT Press.

Nabhan, G., & St. Antoine, S. (1993). The loss of floral and faunal story: The extinction of experience. In S. Kellert & E. O. Wilson (Eds.), The Biophilia Hypothesis (pp. 229–250). Washington, DC: Island Press.

Stepp, J. R., & Thomas, M. B. (2010). Managing ethnopharmacological data: Herbaria, relational databases, literature. Medical and Health Sciences, 13, 116–123.

Wilson, E. O. (1984). Biophilia. Cambridge, MA: Harvard University Press.

Ethnobotany in Practice

Swamp-Pink, Helonias bullata, threatened in South Carolina, photo from USFWS

At the moment, most ethnobotanic work outlined in the last post is done in developing countries.  Despite the vast geographical expanses and travel challenges, the richer biodiversity nearer the equator remains a magnet for collectors.  However, large-scale expeditions are long gone and collecting in the developing world is now tightly regulated.  This is the result of a post-colonial world with all nations justifiably wishing to have sovereignty over their biological resources.  Several international agreements are helping to make this possible.  The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) was presented at a United-Nations sponsored meeting in Washington, DC meeting in 1973.  It controls commerce in endangered species presented in the IUCN Red List.  It comes into play in botany especially with timber from rare trees and exotic plants such as orchids and cacti.  It is the first of several international agreements on the earth’s biodiversity.  CITES regulations are strict, but depend on enforcement which varies among the signatories and with the economic value of the species.

A meeting in Rio de Janeiro in 1993 led to the Convention on Biological Diversity (CBD) that gives each nation sovereignty over its biological wealth.  It aims to prevent developed nations from continuing to exploit the biota of developing nations, most of which had their advance thwarted by centuries of colonial rule.  The CBD represents a major shift in how the biological resources of a country are seen not only economically, but politically and culturally.  Since the ratification of the CBD by most of the world’s nations, these issues have had a significant impact on botany and on herbaria, as they had throughout the history of botany.  The difference now is the aim of equitable distribution of value.  Even non-signatory nations must comply with the procedures set down by those that have signed, so this and the other international agreements have had a significant impact on how the biological wealth of nations is viewed and treated.  This is particularly the case since the ratification of another UN-sponsored document the Nagoya Protocol, a 2011 agreement that grew out of the CBD.  It deals with the genetic resources of plants and animals, and how their benefits can be shared and used fairly and equitably.  It aims to prevent exploitation of resources, for example, by drug companies collecting plants that have medicinal uses and then developing drugs based on them in their home country’s laboratories without sharing profits with the country where the plant was collected and with the people who revealed its medical efficacy.  

Such agreements give a host country the right to set strict limits not only on what can and cannot be collected, but also on how it can and cannot be used after collection.  These restrictions are meant to prevent the kind of exploitation by wealthy nations that was carried out for centuries.  A botanist who wishes to collect in another country must obtain a permit, or a series of permits, to do so.  These delineate what can be gathered, often only specific plant groups and in specific quantities.  Travel might also be limited to particular geographic areas.  Where possible, unless the plant is very rare, it is collected in multiples, and specimens are retained in an institution in the host country as well as in the collector’s institution. 

Requirements and procedures vary widely from country to country, and it may take months if not years to obtain the necessary documents, which in some cases are issued across multiple government agencies at levels going from nation-wide to state, municipality, or other jurisdiction.  This sounds daunting, and it can be.  Some botanists and policy makers argue that the paperwork can be so difficult as to effectively prohibit or severely curtail collection and therefore hinder biodiversity research.  They contend that the requirements can have the opposite effect to what was intended.  The protocol does prevent exploitation, but in some cases it thwarts research that might lead to practical benefits for the country in question.  In a commentary on a recent assessment of the biodiversity on the island of New Guinea, researchers noted that while half the island is part of Indonesia, a signatory to the protocol, the other half, Papua New Guinea, is not.  This is making the latter more attractive for biodiversity research (Novotny & Molem, 2020).

More mundane problems also persist.  Travel in many areas is difficult, as is transport and communication.  Shipments can get lost and may turn up eventually, or may be gone for good.  This is a real concern since there are strict regulations about transporting living material, or material that was at one time living, across borders.  These are definitely legitimate issues about the possible spread of invasive non-native species.  Australia, because of its remoteness, has a large number of endemic species and has had severe problems with invasives causing extinction of native plants and animals.  The invisibility of herbaria and their work have compounded the customs problem, since most nonscientists haven’t heard of herbaria and do not appreciate that specimens are dead not living plants.  The case of Australian customs officials destroying types specimens sent from the herbarium at the National Museum of Natural History in Paris led to an international incident.

Reference

Novotny, V., & Molem, K. (2020). An inventory of plants for the land of the unexpected. Nature, 584(7822), 531–533. https://doi.org/10.1038/d41586-020-02225-4

Ethnobotany

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). 

References

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.

Medical and Economic Botany

The Botanical Café at the Royal Botanic Gardens, Kew

This series of posts deals with how herbaria document plant uses.  It’s an understatement to say that plants are endlessly useful to humans.  They are beyond useful; they are responsible for much of life on earth, fundamental to energy flow on the planet and providing food, medicine, and materials to cloth, shelter, and make our lives richer with everything from chewing gum to violins.  Interest in plants has always centered on how plants benefit humans, with early modern botanists focusing particularly on medicine.  When Luca Ghini was creating his herbarium in the 1530s, he was teaching medical botany, materia medica, a field created by the ancient Greeks and Romans.  But Ghini and his fellow botanists were slowly expanding their range of interests beyond medicine, to observing a broader array of species including those providing food for the kitchen and beauty for the garden (Ogilve, 2006).  Yes, in early herbaria there are plants collected simply because they were novel or had fascinating characteristics, but the preponderance of specimens were from useful plants.  This trend has continued, with such species overrepresented in herbaria to this day (Nesbitt, 2014). 

Well into the 19th century, medical botany remained a major driver of plant collection, and an essential part of a physician’s education and that of pharmacists as well.  Many of the latter also kept herbaria as references, to teach apprentices, and to present their wares to customers.  But other groups were involved as well in studying, gathering, and using plants for healing.  Most religious institutions had herbalists among their members to provide remedies inhouse, and there were women in most areas who grew useful plants in their gardens, shared them with others, and were often called upon for medical advice (Strocchia, 2019).  Many had vast stores of knowledge, but even the literate among them might only jot down notes in the margins of herbals.  Their experiences were rarely shared more widely and in some cases were belittled and even suppressed by the more educated medical practitioners who disliked the competition but were not above learning from those in the lower ranks.  There was a range of relationships among these different classes, and slowly information trickled up and down the social strata (Arber, 1938). 

The same kinds of tensions, though often more intense, arose when explorers began to learn about medicinal botany in other parts of the world.  There were added layers of complexity because travelers and residents shared neither language nor customs, nor in many cases aliments, at least early in their exchanges.  Since most explorers had relatively short stays in any one area, they rarely developed a deep understanding not only of the flora but of how plants was used by indigenous people.  There were exceptions, as with missionaries whose sojourns were long-term and for whom learning the language was vital to their work, as was helping the poor and sick.  They sometimes collected specimens to send home for identification.  Their recording common names was important for later botanists who revisited areas seeking similar species. 

As exploration progressed, plant hunters collected for a wide range of uses of interest in their home countries:  medicines, textiles, foods, timber, and garden plants.  Herbaria are crammed with the results of their enterprise.  By the 19th century, the term economic botany described this broad curiosity for any plants that humans considered valuable, economically valuable.  The term is less popular today, in part because it was used by colonial powers like Britain to highlight how they had discovered and exploited many plants and plant uses of indigenous peoples.  Economic botany collections and museums were popular in the 19th and early 20th centuries to let the public know about the wonderful products derived from plants and all the ingenious uses that primitive peoples had found for them, from arrow poisons to basketry to bark cloth (Nesbitt & Cornish, 2016).  The Royal Botanic Gardens, Kew led the way, with Joseph Banks beginning the collection in the late 18th century, and William Jackson Hooker establishing an economic botany museum in 1847, though it was first called the Museum of Vegetable Products (Teltscher, 2020).  When Henry Shaw established the Missouri Botanic Garden in St. Louis, he created a museum modeled on the one in Kew (McNulty, 2009).  It has recently been restored to much of its former glory as the Sachs Museum, a much better fate than befell many of these establishments.  When their displays became less popular and literally gathered dust, most were dismantled.  Kew had four economic botany museum buildings; now the display is reduced to a few beautiful old display cabinets with remnants from the collection set amid tables in a café housed in one of the museum buildings see image above.  However, the café is supplied with gin made especially for Kew:  economic botany at its best.

Unlike the items in many other such museums that were severely culled, sent elsewhere, or simply tossed out, Kew’s economic botany collection still exists, housed in a storage facility and well-curated.  Today, Kew’s vast store, while no longer of economic importance, is a cultural treasure with many items seen now as works of art or as documents of indigenous peoples’ lives in the past (Cornish & Nesbitt, 2017).  Kew has worked with the Turkano people in Brazil sharing information about British plant hunter Richard Spruce’s 19th-century collections from their region and learning from them about how the same plant materials may or may not be valued today.  This effort is part of a larger one to assist in providing for the future of biodiversity in the region.  Kew recently held a three-day seminar called Botany, Trade, and Empire that dealt with its economic botany collection and how it can be illuminated by the reports directors of British colonial botanical gardens sent to Kew.  These have just been digitized, and the entire event is available online.

References

Arber, A. (1938). Herbals: Their Origin and Evolution a Chapter in the History of Botany, 1470-1670 (2nd ed.). Cambridge: Cambridge University Press.

Cornish, C., & Nesbitt, M. (2017). Vegetable Sheep (Raoulia). In K. von Z. Carroll (Ed.), Botanical Drift: Protagonists of the Invasive Herbarium (pp. 19–28). Berlin: Sternberg.

McNulty, E. (2009). Missouri Botanical Garden: Green for 150 Years, 1859-2009. St. Louis: Missouri Botanical Garden.

Nesbitt, M. (2014). Use of Herbarium Specimens in Ethnobotany. In J. Salick, K. Konchar, & M. Nesbitt (Eds.), Curating Biocultural Collections: A Handbook (pp. 313–328). Kew, UK: Royal Botanic Gardens, Kew.

Nesbitt, M., & Cornish, C. (2016). Seeds of industry and empire: Economic botany collections between nature and culture. Journal of Museum Ethnography, 29, 53–70. https://www.jstor.org/stable/43915938

Ogilve, B. W. (2006). The Science of Describing: Natural History in Renaissance Europe. Chicago: University of Chicago Press.

Strocchia, S. T. (2019). Forgotten Healers: Women and the Pursuit of Health in Late Renaissance Italy. Cambridge, MA: Harvard University Press.

Teltscher, K. (2020). The Palace of Palms: Tropical Dreams and the Making of Kew. London: Picador.

Gardens and Herbaria: Colonial America

Acer saccharinum by Redouté from Michaux’s The North American Sylva, Biodiversity Heritage Library

In this series of posts on gardens (1,2,3), I’ve written primarily of British gardens and gardeners:  women, nurserymen, and acclimatization of exotics in colonial botanical gardens.  Now I want to turn to a subject that combines the themes of these earlier posts:  North American colonial gardens.  Just as the European colonial powers moved plants around the globe, with Brazilian rubber ending up in Malay Peninsula plantations and Asian breadfruit in the West Indies, American colonists were eager to grow European plants and other exotics.  This side of the bilateral trade has been less emphasized than the many North American plants that became prized items in European gardens such as magnolias, kalmias, and tulip trees.

The Philadelphia farmer John Bartram was a well-known exporter of seeds and seedlings of such species to the British textile merchant Peter Collinson, the middle man in dealings with wealthy British gardeners who awaited Bartram’s yearly boxes of botanical treasures.  Collinson also sent seeds and seedlings in return, including fruit trees.  He even shared seeds of a Chinese aster species that had been collected by French Jesuit missionaries and sent home where its seeds were propagated and passed from France to England through the eager network of botanists that existed at the time.  Trading was a way to insure that one was on the receiving end of the next interesting exotic to come along (O’Neill & McLean, 2008).

One of Bartram’s cousin, Humphry Marshall, had a farm in the Brandywine Valley where he created a botanical garden and also an arboretum.  He specialized in exporting tree seeds and seedlings of native trees to such British customers as Joseph Banks, but Marshall also imported European species for local customers.  After the Revolution they were interested in enriching their properties in the new nation with botanic novelties (Harshberger, 1903).  In 1785, Marshall produced the first botanical book about native plants written by an American and published in America, Arbustrum Americanum: The American Grove.  In the same year, a French botanist with an interest in trees, André Michaux, arrived in the United States, sent by the French government to set up a more formal plant exchange than that between Bartram and Collinson.  Michaux brought European plants with him to sell and to trade with collectors.  He set up a nursery in New Jersey where his assistant could grow seedlings from the plants he collected and then send them to France.  Michaux went on to Charleston, South Carolina, which had long had a French flavor because of its Huguenot population, Protestants who had fled Catholic France years before.

By this time the botany of the Carolinas was relatively well known in Europe thanks to Mark Catesby’s The Natural History of Carolina, Florida and Bahama.  Even earlier, James Petiver had a number of collectors who either visited or lived there.  Alexander Garden, a Scottish physician, set up a practice in Charleston in 1752.  He was an enthusiastic botanist, collected in the area and sent plant and animal specimens to John Ellis in England and Carl Linnaeus in Sweden.  Garden corresponded with John Bartram, visited him in Philadelphia, and hosted him on his trip to Charleston.  Bartram was encouraged by Collinson to collect broadly, hence his travels that took him from northern New York to Florida.  In Charleston he met not only Garden, but Martha Logan, a nurserywoman who too was involved in sending and receiving seeds and bulbs (Stearns, 1970).

Michaux’s work for the French government was on a larger scale.  Unlike Logan who had a small plot, he bought over 100 acres outside Charleston, and employed enslaved people to clear the land in preparation for the plants and seeds he began collecting.  He had brought his teenage son, François André, with him and together they explored not only around Charleston but went on more extended trips.  His son returned to France for further education, while Michaux continued to explore and collect plants.  He sent specimens back to botanists at the Paris botanical garden, and also cultivated thousands of plants, shipping them to France.  Most did not survive, which he discovered when he returned to France after 10 years in the United States.

Michaux worked on his specimens at the Paris garden and a few years later was part of an expedition to Africa where he died in 1802.  His son François André Michaux returned to the United States to dispose of the two nurseries and spent time collecting as well.  He traveled to Mexico and around the United States, so he added many species to the ones his father collected.  From 1810 to 1813 he published three volumes of what was translated as The North American Sylva.  The original edition had illustrations by the noted botanical artists Pierre-Joseph Redouté and Pancrace Bessa (see image above).  In 1853 there was a supplement produced with more species, including ones from the West, collected by Thomas Nuttall (Savage & Savage, 1986).

References:

Harshberger, J. W. (1913). Exercises in memory of Humphry Marshall and William Darlington, at Marshallton, Pa., September 27, 1913. Hickman. http://hdl.handle.net/2027/hvd.32044106373145

O’Neill, J., & McLean, E. (2008). Peter Collinson and the 18c Natural History Exchange. Philadelphia: American Philosophical Society.

Savage, H. Jr., & Savage, E. J. (1986). André and François André Michaux. Charlottesville, VA: University of Virginia Press.

Stearns, R. P. (1970). Science in the British Colonies of America. Urbana, IL: University of Illinois Press.