On the Road, Learning about Herbaria: The ESN

Diagram of an Extended Specimen Network (ESN) from Extending U.S. Biodiversity Collections to Promote Research and Education

This post continues my report on the Digital Data Biodiversity Research Conference held at Yale University in June (see 1,2).  Digitizing the nation’s millions of natural history specimens is a massive undertaking.  iDigBio is the National Resource for Advancing Digitization of Biodiversity Collections (ADBC) funded by the National Science Foundation.  As the iDigBio website notes:  “Through ADBC, data and images for millions of biological specimens are being made available in electronic format for the research community, government agencies, students, educators, and the general public.”  Under this umbrella there have been a number of other projects including the TCNs or Thematic Collection Networks, through which particular types of collections were digitized with a focus on research questions that could be answered by the digitized data.  For example, there was one on insect herbivores, their parasitoids, and their host plants.

Another related project just being completed is the Biodiversity Collections Network (BCoN) “to support the development of a new, sustainable community of practice that will ensure that all U.S. biodiversity collections are digitally available for research, education, informed decision-making, and other scholarly and creative activities.”  This spring, BCoN released a report along with an informative summary.  The report develops the concept of yet another acronym, the ESN or Extended Specimen Network.  Now that information on a substantial number of natural history specimens has been digitized, the biodiversity science community is looking at ways to maximize use of this data, as well as opening it to new user communities.

The ESN is an exciting idea with specimens as the focus.  There are three layers of extensions out from the specimen (figure above).  First, the digital specimen record and an accompanying specimen image, or in some cases, a 3-D image file.  Second would be links to field notes and images, gene sequences, morphometrics, and isotope data.  The third includes phylogenies, species descriptions, ecological interactions, distribution maps, and protection status locations.  The report envisions that a user could enter the name of a species into a portal and from that one portal be able to access all these types of information for that species.  This would be a dream come true for biologists and might be a way to counteract the increasing specialization that has so changed the discipline over the past 200 years:  geneticists being able to easily call up information on the source species for a gene sequence and ecologists finding phylogenies for related species in an ecosystem.

Right now the ESN is more a concept than a reality.  Yes, at least some of the circles in this diagram are connected to each other for at least some species or for some geographic areas.  As I discussed in an earlier post, projects such as NEON and the Map of Life (MOL) are moving in the direction of integrating at least some of these pieces, but also as mentioned in that post, the problems of integration are massive.  It is as if iDigBio and other projects have amassed the building blocks for an intricate structure, most of which remains unbuilt, with even the plans in a rudimentary stage, and with developers trying to devise tools that will allow the building to continue.  Still, I find the ESN an exciting idea and can’t wait to see it evolve.  In the two years since the first Digital Data conference, projects such as MOL have made amazing strides, and so the next conference scheduled for Indiana University in 2020 will surely show significant progress on the ESN.

At the end of two days of presentations, there was a reception and poster session in the great hall of Yale’s Peabody Museum of Natural History.  This venue is noteworthy because of The Age of Reptiles, a massive mural depicting the history of dinosaurs on earth (Volpe, 2007).  It was created by Rudolph Zallinger in the 1940s and covers one long wall of the main gallery.  My poster stood under it and presented the argument that the ESN should be extended even further to include more historical material, and that biodiversity digitization projects should be linked to such large-scale digital humanities projects as the Darwin Correspondence Project and the website for the Dumbarton Oaks exhibit on the Botany of Empire in the Long Eighteenth Century.  In fact, JSTOR, the digital library database, and Dumbarton Oaks Research Library hosted a workshop in late 2017 in which they brought together historians of science, librarians, and technical experts to brainstorm and come up with ideas for future work in connecting biodiversity studies and the humanities.  There they developed ideas for linking different resources that are reminiscent of the ESN, including one where the focus would be on taxa.  Other possible points of entry could be through a geographic area, an expedition, and a collector or taxonomist.  There is an interesting video on the workshop that gives a good recap of its work.

My dream is that those involved in the ESN would meet with a group similar to the one convened at Dumbarton Oakes Library, and that they would explore where their various inquiries intersect.  A couple of years ago, E.O. Wilson (2017) published The Origins of Creativity, in which he argues that the sciences and humanities are much more intertwined than is usually assumed.  It would be a fitting tribute to the person who made the word biodiversity so central in present-day biology, to work toward interconnectivity between these two great accomplishments of the human species.


Volpe, R. (2007). The Age of Reptiles: The Art and Science of Rudolph Zallinger’s Great Dinosaur Mural at Yale. New Haven, CT: Peabody Museum of Natural History.

Wilson, E. O. (2017). The Origins of Creativity. New York, NY: Norton.


On the Road, Learning about Herbaria: Education and Citizen Science

BLUE Port: Biodiversity Literacy in Undergraduate Education

In the last post, I described sessions I attended at the Digital Data Biodiversity Research Conference at Yale University.  Besides presentations on portals that integrate various kinds of data and on projects to create and analyze 3-D images of specimens, there was an emphasis on education.  Now that so much specimen data and other biodiversity information is available digitally, one of the major goals of iDigBio, the National Resource for Advancing Digitization of Biodiversity Collections (ADBC) funded by the National Science Foundation, is to have this data used widely.  This requires education, both of the present research community and of its future members.  For several years, iDigBio has been holding workshops and conferences, like the one at Yale.  These have resulted in a major upswing in the number of studies and publications employing biodiversity data.  Now that many professionals are trained in how to access and analyze the available information, it’s time to leverage this knowledge.  The task is to help these experts teach the next generation.

As every teacher realizes, knowing something is very different from teaching about it.  The subject matter has to be analyzed and organized; ways into the basics have to be found; a learning structure has to be created.  For many years, I was involved with the BioQUEST Curriculum Consortium and attended a number of workshops dealing with using genomic data in teaching genetics and bioinformatics.  The portals for gene sequence data are extremely powerful, but they were built for researchers who committed a great deal of time to learning to use them effectively.  Teachers, and even more so students, do not have the time, the technical support, nor the expertise to make effective use of these portals.  That’s where BioQUEST and other initiatives came into play.  At the workshops I attended, we learned enough about the available resources to “tame” them, to download data and present it to students in a way they could understand and use.  We became part of an education community committed to bringing students into the genetic sequencing research space in a way that would make sense for them.

Now the same kinds of initiatives are being developed for biodiversity research using powerful tools like iDigBio, GBIF, NEON, and MOL discussed at the conference (see last post).  Anna Monfils of Central Michigan University is the principle investigator for an NSF-funded project called BLUE: Biodiversity Literacy in Undergraduate Education that includes participation from BioQUEST.  Monfils and members of her team led a lively session at the conference on the question of what biodiversity literacy means and how to achieve it.  As the conversation developed, it became clear that these are not easy issues to resolve.  However, the BLUE project is a great first step in defining what a biology student needs to have in terms of conceptual understanding and technical skill to tackle the vast ocean of biodiversity data now available to them.  What didn’t arise as strongly is an issue that is dear to my heart:  how do you make biodiversity data understandable and accessible to students who are not majoring in biology or environmental science?  One of iDigBio’s aims has been to broaden the community of biodiversity data users, and non-scientists make up a huge audience.  Taming data for them is very different than for those interested in science, but everyone encounters organisms in their lives every day, so why not make it easier to learn more about them?

One way into such learning is through an area that has burgeoned in the last few years and that had a larger presence at the conference than in the past:  citizen science.  The field has many different aspects from political advocacy to volunteer data entry.  Examples of the latter include the development of portals such as Notes from Nature, where many institutions with natural history collections post well-defined projects such as digitizing specimen data.  The Smithsonian has an online transcription center where notebooks, journals, and letters are posted.  All these sites have sophisticated digital architectures that allow data managers to have confidence in the input, such as by having the same data entered by more than one user and then compared.  Many of those involved have commented on how fast the projects are completed.  Sometimes thousands of individuals participate, with a number being very committed and doing a great deal of data input.  In cases like this, citizen science is another name for unpaid help or volunteering.  With an increasing number of retirees looking for something interesting to do, these projects are very attractive because there is no commute involved and fascinating things to learn.

Still another type of citizen science work is done by those who use portals such as iNaturalist to record field observations and phenological information.  These data ultimately are uploaded into GBIF, a global biodiversity portal, and the citizen science input has grown to the point where it is having a significant impact on biodiversity research.  Walter Jetz of Yale University and principle investigator for the Map of Life (MOL) project, commented on the importance of citizen science several times in his presentation.  Not surprisingly, this is particularly true in ornithological research where amateurs have always been especially welcomed by the scientific community.

On the Road, Learning about Herbaria: Digitization

iDigBio Portal

I recently went north, to Yale University, for the third annual Digital Data Biodiversity Research Conference, sponsored by iDigBio, the NSF-sponsored project to digitize natural history specimens.  I attended the first of these conferences two years ago at the University of Michigan (see earlier post).  Both were fascinating and informative, but also different from each other, in that the focus of attention in this field has moved beyond digitizing collections to using digitized collections.  This seems a healthy trend, but as Katherine LeVan of National Ecological Observatory Network (NEON) mentioned, only 6% of insect collections have been even partially digitized, and Anna Monfils of Central Michigan University noted that iDigBio has information from 624 of 1600 natural history collections in the United States.  Admittedly, it’s mostly small collections that aren’t represented, but Monfils went on to show that smaller collections hold larger than expected numbers of local specimens, providing finer grained information on biodiversity.

Despite the caveat about coverage, the results of the NSF funding is impressive and is leading to an explosion in the use of this data.  It is difficult to keep up with the number of publications employing herbarium specimens as sources of information for studies on phenological changes, tracking invasive species, and monitoring herbivore damage.  While the earlier conference included sessions on using data for niche modeling, the meeting at Yale also had presentations on how to integrate such data with other kinds of information.  Integration was definitely a major theme, and two large-scale projects are front and center in this work.  Nico Franz of Arizona State University is principle investigator in NEON, a massive NSF-funded project that includes 22 observatories collecting ecological data, including specimens, and then using that data in studies on environmental change.  Franz noted that while other projects might collect data over short periods of time, NEON plans for the long-term and for building strong communities sharing and using that data.

Another large sale project, one headed by Yale professor Walter Jetz, is called Map of Life (MOL).  Here again, integration is central to this endeavor that invites researchers to upload their biodiversity data and also to take advantage of the wealth of data and tools available through its portal.  As the name implies, biogeography is an important focus, and users can search for distribution maps for species and create species lists for particular areas .  As with many digital projects, this one still has a long way to go in terms of living up to its name, which implies a much broader species representation than is now available.  In a session led by MOL developers, it became clear that the issue of how different kinds of data can be integrated is still extremely fraught.  Even databases for different groups of organisms, vertebrates versus invertebrates for example, are difficult to integrate because important data fields are not consistent:  what is essential in one field, might not be noteworthy at all in another or might be handled in a different way.  Progress is being made, but as Roderick Page of the University of Glasgow notes, even linking to scientific literature is hardly a trivial task, to say nothing of more sophisticated linking.

While this may seem discouraging, there were also many bright points in the presentations.  The massive Global Biodiversity Information Facility (GBIF) has, as I write, 1,330,535,865 occurrence records, that is, data on specimens and observations.  Last year, GBIF launched an impressive new website and often adds new features.  While the tools available through GBIF are not as sophisticated as with some other portals, it is still an incredible resource since iDigBio data is fed into GBIF as well as data from projects around the world.  For example, data from the University of South Carolina, Columbia A.C. Moore Herbarium where I volunteer, which was fed into SERNEC and iDigBio, is now also available in GBIF, so researchers worldwide can access data on this collection that is particularly rich in South Carolina plants.  This was not an easy undertaking—nothing in the digital world is—and it’s important to always keep that in mind as developers have flights of fancy about could be possible in the future.

Another conference highlight for me involved the use of sophisticated neural network software, such as that coming out of the Center for Brain Science at Harvard University.  James Hanken, Professor of Zoology and Director of the Museum of Comparative Zoology at Harvard, reported on a project to scan slides of embryological sections and then use the neural network software to create 3-D reconstructions of the embryos.  Caroline Strömberg of the University of Washington discussed a project to build a 3-D index of shapes for phytoliths, microfossils from grass leaves that can be more accurate for identifying species than pollen grains.  Her lab has studied 200 species and has quantified 3-D shapes, even printing them in 3-D to literally get a feel for them.  They used this information in a study of phytoliths from a dinosaur digestive track suggesting that grasses are older than previously thought.  Others have questioned these results, so Strömberg’s group is now refining the identification process, measuring more points on the phytolith surface.  Reporting on another paleontological study, Rose Aubery of the University of Illinois described image analysis done with Surangi W. Punyasena on plant fossil cuticle specimens to obtain taxonomic information about ancient ecosystems.  What all these presentations had in common was the use of massive computational power to analyze 3-D images.  At the first conference, reports of 3-D imaging were impressive, but now it is the analysis that has taken center stage.  This is a good sign:  all that data is proving valuable.

Darwin’s Botanists: Asa Gray

Holotype of Abutilon parvulum collected by Charles Wright for Asa Gray, Harvard University Herbaria.

This last post in the series (1,2,3) on Charles Darwin and the botanists who supported his work deals with an American, Asa Gray (1810-1888).  He received his medical degree at Yale University, but like Joseph Dalton Hooker (see last post), had little interest in practicing and a great desire to learn more about plants.  He taught at Utica College in central New York State for a short time, while collecting in the area and creating exsiccatae of grasses and sedges (Gray, 1834).  He was eventually drawn to work with John Torrey, a botanist who was teaching botany part time at Columbia College in New York City while also teaching chemistry at Princeton University.  Torrey was impressed with Gray’s herbarium and paid for him to collect in New York and New Jersey.  After this, Gray moved in with Torrey’s family and organized his herbarium.  This gave Gray an opportunity to see many more species than he had encountered up to this time.  He remained with the Torreys for two years until he was offered a position as professor of botany at the newly formed University of Michigan.

In preparing for this post, Gray traveled to Europe to purchase books and equipment, and also to consult much richer herbaria than those available in the US, even for American species.  Visiting Glasgow, Gray stayed with William Jackson Hooker for three weeks examining his North American plants, including many collected by Thomas Nuttall.  Gray discovered that most of the specimens were from northern areas of North America, with the south and west still relatively unexplored.  John Lindley of the Royal Horticultural Society let him take portions of the specimens said to have been collected by Thomas Walter in the Carolinas in the 1700s, something that would be unheard of today (Dupree, 1959, p. 80).  Having gathered a wealth of information, Gray returned home to find that the University of Michigan was still not ready to have him begin work.  When offered a similar position at Harvard University, with the additional responsibility for its botanical garden, he moved to Cambridge and remained there for the rest of his life. 

Gray continued to work with Torrey on the deluge of specimens coming in from US-sponsored expeditions and surveys, including the Wilkes Expedition’s 50,000 plant specimens.  This necessitated another trip to Europe to consult herbaria in Britain and France with their superior holdings of North American plants.  Torrey and Gray did much to eventually alleviate this problem by creating large collections at their home institutions of Columbia and Harvard, while the Wilkes specimens became the nucleus of the US Herbarium at the Smithsonian Institution.  Like Joseph Dalton Hooker (see last post), Torrey and Gray became “imperial” botanists, in that they attempted to retain control over collectors and discourage them from describing species themselves.  They claimed that those gathering specimens didn’t have the knowledge, reference collections, or literature to do the job. 

In 1843, US Navy Commodore Matthew C. Perry signed a treaty with Japan that began to open the country to trade.  While Perry had not wanted a natural history collector on the expedition, two Americans associated with the mission, one a friend of Gray’s, did make a small plant collection and sent it to Cambridge.  What struck Gray about these plants, as well as some other Japanese species he had encountered, was how similar they were to those of the northeast US.  When he had examined a broad enough selection, he arranged them in a table and found that of 580 Japanese species, fewer were in western North America than in Europe, and far more were in eastern North America than in either of the other areas.  Considering this odd result, he posited that the plants in these two areas had a common ancestry.  Due to fluctuating climates, which remained most similar in eastern North America and Japan, the species were better able to survive in these regions.  This was a significant piece of evidence for evolution and Charles Darwin was very pleased with it.

Gray and Darwin began their correspondence in 1855.  Darwin appreciated Gray’s acceptance of species change, though he was less pleased that Gray held that creation still had a role in life on earth.  Gray presented this view most fully in an article in the Atlantic Monthly in 1861, “Natural Selection Not Inconsistent with Natural Theology.”  While disagreeing with it, Darwin did see it as a way to lure more people into the evolutionary fold and arranged for it to be reprinted in Britain (Dupree, 1959, p. 155).  Like Hooker, Gray also provided Darwin with much botanical information for his post-Origin plant studies.  They both experimented in their gardens, and Gray could provide seeds and cuttings of American plants.  In his own work, Gray was stymied by the amount of administrative work he was required to do at Harvard without adequate assistance.  Until he retired, he was the only professor of botany, and the University had never created an infrastructure for botanical research.  Gray managed to set the stage for this at his retirement by donating his herbarium of 220,000 specimens and his library of over 2,200 books to the University and managing the hiring of a staff to at last create a department of botany.   


Dupree, A. H. (1959). Asa Gray: American Botanist, Friend of Darwin. Cambridge, MA: Harvard University Press.

Gray, A. (1834). North American Gramineae and Cyperaceae (Vols. 1–2). New York, NY: Post.

Darwin’s Botanists: Joseph Dalton Hooker

Illustration of Rhododendron glaucum from Joseph Hooker’s The Rhododendrons of Sikkim-Himalaya, Biodiversity Heritage Library.

Joseph Dalton Hooker (1817-1911) was born into the botanical world.  His father was William Jackson Hooker (1785-1865), a botany professor at the University of Glasgow who then became director of the Royal Botanic Gardens, Kew.  Joseph eventually succeeded his father in that post, but his career had more bumps than this succession might suggest.  The Hookers did not have the wealth of the Darwins, so they needed salaried appointments in order to pursue their interest in science, something Charles Darwin never had to consider.  William could provide for his family, but as an adult, Joseph had to find his own means of support after graduating with a medical degree from the University of Glasgow.  Eight years younger than Darwin, Joseph Hooker took a similar route to gain experience in natural history by participating in the British Navy’s Ross Expedition to Antarctica, serving as assistant surgeon; both he and the surgeon were also charged with collecting natural history materials.  Setting out in 1839, they visited South Africa and several groups of islands on their way to and from Antarctica, as well as Australia, New Zealand, and Tierra del Fuego. 

By the time Hooker arrived back in Britain four years later, he had not only amassed a large herbarium but also made many drawings.  Like his father he was an accomplished botanical artist and created many of his own illustrations, especially for his early publications.  On his return to Britain, he began work on studying his collection and publishing descriptions of new species.  Hooker also analyzed some of Darwin’s specimens from the Beagle expedition.  Eventually Hooker described many of them and in the process became quite friendly with Darwin who was thrilled to have his plant collection studied after the long delay in John Henslow’s hands (see last post).  Their friendship flourished and continued until Darwin’s death.

In 1841 William Hooker became director of Royal Botanic Gardens, Kew, but there was no paid position available to his son.  Joseph applied to be professor of botany at Edinburgh, but didn’t get the job, so he worked for the British Geological Survey and learned paleobotany.  In 1847, he went on another expedition, this time to the Himalayas as a plant collector financed by Kew.  He sketched many of the plants, especially the rhododendrons, and it is amazing how beautiful these sketches are considering the rough conditions under which he worked (see above).  When Joseph returned to Britain he went to work on his collections, and finally obtained a paid position at Kew as his father’s assistant in 1855.  Ten years later, when his father died, he became director and was paid to cede the elder Hooker’s herbarium to Kew where he could still have access to it. 

In the meantime, Darwin had been developing his ideas on evolution, having written up a 230 page “summary” in 1844.  He had copies made and gave them, in sealed envelopes, to his wife Emma and to Joseph Hooker so that in case of his death it could be published, though he wasn’t ready to do the deed himself.  At one point after this, Hooker bluntly suggested that while Darwin’s interests were definitely broad, extending from variation in domesticated animals to fossils to plant breeding, he really hadn’t delved deeply into any one group of organisms.  He needed to study some segment of the living world so closely that he would get a sense of the issues involved in distinguishing one species from another.  This was the start of Darwin’s eight-year odyssey studying barnacles that resulted in a two-volume publication on them.  Janet Browne (1995) sees this as Hooker’s most significant contribution to Darwin’s thinking. 

Hooker was also very involved in dealing with the crisis that overwhelmed Darwin when he received a letter from Alfred Russel Wallace in 1858 outlining a theory of natural selection very similar to Darwin’s own.  Hooker and the geologist Charles Lyell calmed Darwin down and devised a plan in which they presented Wallace’s paper, along with a short summary of Darwin’s work, at a meeting of the Linnean Society of London (Browne, 2002).  This was another major event in Hooker’s relationship with Darwin and led to Darwin’s writing On the Origin of Species (1859) within a year.  Though they didn’t always agree on all the finer points of the theory, Hooker remained an important support to Darwin especially because in the years after publication of The Origin, Darwin wrote a number of major works on plants.  Hooker supplied not only advice and taxonomic assistance, but also sent Darwin orchids and other plants from Kew. 

Hooker had an illustrious career in his own right as described in Ray Desmond’s biography (1999).  In Imperial Botany, John Endersby (2008) takes a different tack toward Hooker’s profession and analyzes how he used his position at Kew to command an army of collectors around the world to add to the already outstanding herbarium his father had amassed.  Endersby argues that Hooker was intent on remaining in control of plant taxonomy, particularly of naming new species.  He sternly directed collectors to send the material to Kew rather than attempt to describe species themselves.  Such tight reins were difficult to maintain as collectors became more knowledgeable about the plants where they lived and collected, for example, in Australia and India.  Hooker’s argument was that they lacked the broad collection he had available and so tended to see something as a new species, when it was only a variant (Boulter, 2009).  In other words, colonial botanists were splitters and imperial botanists like Hooker were lumpers.  During his career, Hooker published an impressive array of books including Genera Plantarumwith George Bentham, The Rhododendrons of Sikkim-Himalaya, and Flora of British India, as well as works on plants he collected in Tasmania, New Zealand, and Antarctica. 


Boulter, M. (2009). Darwin’s Garden: Down House and the Origin of Species. Berkeley, CA: Counterpoint.

Browne, J. (1995). Charles Darwin: Voyaging. Princeton, NJ: Princeton University Press.

Browne, J. (2002). Charles Darwin: The power of place. Princeton, NJ: Princeton University Press.

Desmond, R. (1999). Sir Joseph Dalton Hooker: Traveller and Plant Collector. Kew, UK: Royal Botanic Gardens, Kew.

Endersby, J. (2008). Imperial Nature: Joseph Hooker and the Practices of Victorian Science. Chicago: University of Chicago Press.

Darwin’s Botanists: John Stevens Henslow

Specimens of Phleum arenarium in the John Henslow Herbarium, Cambridge University.

John Stevens Henslow is perhaps best known today as Charles Darwin’s botany teacher at Cambridge University and as the person who presented Darwin with an invitation to join the Beagle surveying expedition headed by Captain Robert FitzRoy.  However, this leaves out the herbarium part of the story, obviously the good part.  It’s not surprising that Henslow had an herbarium, but the way he handled his specimens was a little different.  In an article called “What Henslow Taught Darwin,” a team of researchers found that two-thirds of Henslow’s sheets at the Cambridge University Herbarium are what he termed “collated,” that is, having more than one specimen (Kohn et al., 2005).  This doesn’t seem noteworthy, especially for small plants, but their placement is interesting.  They were sometimes arranged in order of increasing height (see above), or with the largest specimen in the middle and specimens in descending height order on either side.  In many cases, specimens on a sheet included ones with different collectors, dates, and locations. 

Many of the specimens were collected around the time Henslow was teaching Darwin and also working on variation within plant species.  He grew Primulas, varying the amount of moisture, manure, and shade, noting that they differed in ways often seen in the field.  Earlier, he had made drawings of the different lengths of styles and stamens in cowslips, Primula veris, something Darwin later investigated.  Kohn and his coauthors argue that the specimens and observations on variation that Henslow presented in his lectures became part of Darwin’s “mental architecture,” so much a part of his thinking that he might not have even realized the debt he owed to Henslow.  This wasn’t just from the three cycles of Henslow lectures that Darwin attended.  Janet Browne (1995) notes that they became closest during Darwin’s last months at Cambridge when they often went on walks and collecting trips, and dined together at Henslow’s house.  It was then that Henslow arranged for his student to accompany Adam Sedgewick, Cambridge’s professor of geology, on a field trip to Wales.  This cemented Darwin’s interest in geology, which was important to his observations on the Beagle.  It was also when Darwin’s oldest known herbarium specimens were collected, three Matthiola sinuata, that were collated by Henslow on a single sheet along with another example collected by a Miss Blake.    

Darwin had an opportunity to collect many plants on the Beagle expedition, hundreds of them, which he sent to Henslow along with animal skins, fossils, etc.  After shipping the first package, he had to wait two years for a letter from Henslow to catch up with him.  In the meantime, he worried that no correspondence meant that Henslow wasn’t pleased with what he sent.  He was relieved to finally read that Henslow was grateful for the materials.  However, his mentor did comment that Darwin shouldn’t send scraps, that the entire plant should be included when possible—leaves, roots, stem, flowers—and that one of the leaves should be turned back to reveal the underside.  Also, it wasn’t necessary to sew down the specimens; they traveled better when left loose (Allan, 1977). 

Soon after his return to England, Darwin delivered the last batch of specimens in person, and Henslow agreed to begin work on identifying them.  However, this turned out to be a slow process, in part because the assignment coincided with Henslow’s move from Cambridge to become vicar at a church in Hitcham, almost 50 miles away.  He remained a Cambridge professor, but usually only visited there to give his lectures.  Another problem was that so many of the plants were unfamiliar to Henslow.  Darwin kept prodding him for several years, until eventually Henslow turned the specimens over to the young botanist Joseph Dalton Hooker, who had himself just returned from a round-the-world expedition with the British Navy.  Hooker found that many of the plants that Darwin collected on the Galapagos Islands were endemic to the islands, and in many cases, occurred on only one Island, information that Darwin was relieved to hear since it fit with his observations on birds and other animals.

Henslow might not have had time for Darwin’s plants, but he made a number of other contributions to botany (Walters & Stowe, 2001).  He revitalized the botany program at Cambridge University.  It had become rather dormant under the nearly 60-year reign of Thomas Martyn, who spent much of his time as a London physician.  He overhauled the herbarium, which had become disorganized.  Henslow made it known that he was building the collection, particularly with plants from Cambridgeshire and Great Britain, and received notable donations.  He pressed for a new, larger botanic garden at the university to replace the one that had fallen into disrepair and then oversaw this project.  Henslow’s lectures were well-received, and they were accompanied with specimens and with charts he drew.  He wrote and illustrated a text to go with his course, and later, with help from his daughter and the noted artist and engraver Fitch, published a series of large botanical charts for sale to schools (Burk, 2005).  Henslow wrote papers on plant variation and on zoological aspects of natural history, most before his move away from Cambridge.  In all, he produced significant contributions to botanical science besides serving as Darwin’s mentor and travel arranger. 


Allan, M. (1977). Darwin and His Flowers: The Key to Natural Selection. New York, NY: Taplinger.

Browne, J. (1995). Charles Darwin: Voyaging. Princeton, NJ: Princeton University Press.

Burk, W. (2005). Henslow’s wall charts: A legacy of botanical instruction. Bulletin of the Hunt Institute for Botanical Documentation, 17(1), 4–6.

Kohn, D., Murrell, G., Parker, J., & Whitehorn, M. (2005). What Henslow taught Darwin. Nature, 436, 643–645.

Walters, S. M., & Stow, E. A. (2001). Darwin’s Mentor: John Stevens Henslow, 1796-1861. Cambridge, UK: Cambridge University Press.

Darwin’s Botanists: In the Family

Frontispiece for Eramus Darwin’s The Botanic Garden, Biodiversity Heritage Library

In this series of post’s I’ll be discussing key botanists who influenced Charles Darwin’s work:  John Stevens Henslow, Joseph Dalton Hooker, and Asa Gray.  But first I’ll look at those closer to home who were important to Darwin’s development as a naturalist.  The most obvious is his grandfather, Erasmus Darwin, a physician with broad interests including botany.  He worked with two others in his town of Litchfield to translate some of Linnaeus’s work, and after that wrote a volume of poetry, The Love of Plants, as an introduction to the Linnaean classification system.  It was well-received and was followed by The Economy of Vegetation; the two were then published together as The Botanic Garden.  There are hints of evolutionary thinking in them, but are more overt in Zoonomia, a two-volume medical work with a chapter on generation that presents a somewhat Lamarckian view of species change.  Erasmus died before Charles Darwin was born, so most of his grandfather’s influence on him was through his writings.  By the time Charles was studying at Cambridge, he was aware of Erasmus’s ideas as well as those of Lamarck.

Darwin’s father Robert was also a physician interested in botany, though not a writer.  However, he took pleasure in gardening with his children.  This is probably how Charles was first introduced to nature, and he early had a fascination with plants and animals, with closely observing nature as every good gardener must.  Since it’s impossible to garden without encountering insects, it was probably in working with his father that Charles developed his interest in insects and became a collector.  Robert also kept a notebook where he recorded phenological events such as first flowerings, something that his son and grandsons also did.  At one point Robert set the young Charles the task of counting the number of peony blooms each year.  What I find interesting about this is that the number varied from 160 to 363, an impressive display.

Robert Darwin hoped that Charles would follow in his father’s and grandfather’s footsteps, not only in gardening but in becoming a physician as Robert’s older son, Erasmus, did.  But after spending two years at the University of Edinburgh studying medicine, Charles had to break it to his father that he was not cut out to be a physician (Browne, 1995).  It was a tremendous relief to be free of that burden, and Robert sent his son off to Cambridge to become a clergyman, a profession that was at the time full of naturalists.  At Cambridge Darwin met the cleric/professor of botany, John Stevens Henslow, but that is the story of the next post.

While at the university, Darwin became friendly with a cousin, William Darwin Fox, who was also interested in natural history, particularly entomology.  It was Fox who introduced Darwin to the wonders of beetles.  This was a time when divisions between biological disciplines was permeable so in hunting for beetles it was impossible not to take an interest in birds, plants, and even aquatic life that filled the wetlands around Cambridge.  After acquiring a microscope from a friend, Darwin became fascinated by the world of aquatic invertebrates and studied their reproductive cycles.  There seemed to be no aspect of natural history that didn’t engage him.  At the end of his time at Cambridge, he went on a geological fieldtrip to Wales with Adam Sedgewick, professor of geology, and there he made what is considered his oldest existing herbarium sheet. 

After Cambridge came Darwin’s five years of travel on the Beagle which involved collecting specimens that he sent back to Henslow.  In fact, Henslow served as receiver for all eight shipments of plants, animals, fossils, and rocks that Darwin had amassed.  I’m skipping forward very rapidly, but much of this story is familiar to many of you, and for those who want more detail, Janet Browne’s two-volume biography is a joy to read (1995, 2002).  As he was creating the first draft of his theory of species change in 1838, Darwin decided to marry Emma Wedgewood.  They had 10 children, seven of whom lived to adulthood, and all were assistants in his work to a greater or lesser extent.  They pitched in with the endless experiments Darwin devised at Down House, their home in the country outside London.  As they got older, they took on more responsibility.  His daughter Henrietta was his editor and proofreader, and his sons George and William made many of the drawings for his botanical works.  Darwin even engaged George Sowerby, a member of a distinguished family of natural history artists, to teach engraving to George Darwin, whose daughter became the famous printmaker Gwen Raverat.  She also wrote a great book on growing up a Darwin in Cambridge (1952).

Francis Darwin was the son who was most involved in Darwin’s later scientific work, particularly in investigating plant movements and phototropism.  Francis’s first wife died in childbirth.  To ease his grief, his parents urged him to move back to Down House with his infant son.  This is when his collaboration with his father became particularly close, and they co-authored The Power of Movement in Plants, published in 1880, two years before Charles’s death.  Francis also edited collections of his father’s letters.  So even without going outside his family, Darwin received a great deal of inspiration and assistance from those related to him, across the generations.  In the following posts, I’ll discuss some of those outside the family who were also important to his botanical work.


Browne, J. (1995). Charles Darwin: Voyaging. Princeton, NJ: Princeton University Press.

Browne, J. (2002). Charles Darwin: The power of place. Princeton, NJ: Princeton University Press.

Raverat, G. (1952). Period Piece: A Cambridge Childhood. London: Faber & Faber.

The 18th-Century Passion for Botany: Philosophy

4 Rousseau Gentiana filiformis

Gentiana filiformis specimen from the Rousseau herbarium, Jean-Jacques Rousseau Museum, Montmorency, France

The argument I am making in this series of posts (1,2,3) is that in the 18th century there was an interest in natural history, and particularly in plants, that was both intense and pervasive among European educated classes.  Statesmen like the British Prime Minister, Lord Bute, merchants such as George Clifford, and noblewomen including the Duchess of Portland were fascinated by, if not obsessed with, the plant world.  This extended well beyond enjoying gardens or just decorating with plants; they studied botany, learning as much as they could about plant taxonomy with the help of the Linnaean method.  They went so far as to dissect flowers, coax exotic species into bloom, attempt hybridization experiments, and of course, keep herbaria.  With this cultural background, it is hardly surprising that two of the most influential writers of the day were also fired with botanical zeal:  Jean-Jacques Rousseau and Johann Wolfgang von Goethe.

Rousseau became serious about botany around 1764 while he was living in Switzerland (Cook, 2012).  This fit with his philosophy of humans being linked to nature.  Like many of that era, as soon as he became interested, he had a thirst to learn more and more about plants, including how to identify them.  Rousseau was not particularly taken with the Linnaean system, though he studied it.  He was instructed in it by two Swiss physicians as mentors who went on plant collecting tours with him and taught him to press plants for a herbarium.  Rousseau really took to the practice and created beautiful specimens mounted on pages framed in red ink (see figure above).  He also corresponded with the botanist, Joseph Dombey, who sent him over 1500 rare specimens to study.  Rousseau was fascinated by plant form, by the visible similarities and differences among species.  He saw botany as a way to calm the emotions by focusing the mind on something outside itself.

Rousseau was closely tied to the intelligentsia of the day and corresponded with a number of well-educated women of the elite.  He visited the Duchess of Portland (see earlier post) when he went to Britain in 1767 and botanized with her.  He had already been in correspondence with her and sent her two small herbaria.  He also was in contact with Madeleine Delessert, the wife of a financier.  She prevailed on him to give her instruction on how to teach her daughter about plants.  This was the origin of his book of eight letters on botany.  It is a lovely little work, especially because the final chapter is on how to create a herbarium—what more could you ask for in botanical instruction?  In 1785, the British botanist Thomas Martyn translated the letters into English, but gave them a more Linnaean slant than Rousseau had.  In the early 19th century, the letters were published with illustrations by none other than the great botanical artist Pierre-Joseph Redouté, a beautiful tribute to the philosopher (Rousseau, 1979).

One of those influenced by Rousseau’s botanical work was Johann Wolfgang von Goethe.  He became interested in plants when he was made an administrator in Weimar and had to deal with agricultural and forestry management.  As with so many others, he then grew fascinated by plants for their own sake.  He read Linnaeus’s books as well as Rousseau’s botanical writings and tried to work out the similarities and differences among species.  Goethe started a herbarium and also began sketching plants and plant structures (Schulze, 2006).  The turning point in his interest came when he traveled south to Italy and was struck by all the new and intriguing plants he encountered.  They had some similarities with those in Germany, but there were also tremendous differences, especially in the greater variety of species, the number of variations on botanical forms.

As he tried to make sense of this multiplicity, Goethe had a flash of insight when he visited the botanical garden in Padua.  There he saw a palm tree and studied the variations in the forms of its leaves.  He became fixated on leaves and the idea came to him that all plant structures on a stem: leaves, flowers, and the parts of flowers were variations on a basic leaf form.  He came to realize that it was impossible to visualize this Urblatt, as he called it, or to draw it; it was an ideal, a mental construct.  This was also the case with what he termed the Urpflanze or basic plant from which derived all the different plant forms.  He was not thinking in evolutionary terms but more Platonically of an ideal form.  Goethe developed his concept in a book on plant metamorphosis.  While some consider it of little importance in the development of modern botany, others see it as seminal in that he examined questions of relationships among forms that are still relevant today.  One in the second group was Agnes Arber, a noted plant morphologist of the first half of the 20th century who published an English translation of Metamorphosis (Arber, 1946) and wrote The Natural Philosophy of Plant Form (1950) that built on Goethe’s ideas.  Arber saw the basic plant unit as the leaf-as-partial-shoot, and her work received some vindication at the end of the 20th century when the genes responsible for flower structures were discovered and the ABC model of flower development form was published (Haughn & Somerville, 1988).  To me, this is a wonderful story of how fundamental ideas can resurface in new ways as science develops.  It’s another example of where the passion for plants can lead.


Arber, A. R. (1946). Goethe’s botany. Chronica Botanica, 10, 63–126.

Arber, A. R. (1950). The Natural Philosophy of Plant Form. Cambridge: University Press.

Cook, A. (2012). Jean-Jacques Rousseau and Botany: The Salutary Science. Oxford, UK: Voltaire Foundation.

Haughn, G. W., & Somerville, C. R. (1988). Genetic control of morphogenesis in Arabidopsis. Developmental Genetics, 9(2), 73–89.

Rousseau, J.-J. (1979). Botany: A Study of Pure Curiosity (K. Ottevanger, Trans.). London: Michael Joseph.

Schulze, S. (2006). The Painter’s Garden: Design, Inspiration, Delight. Frankfurt, Germany: Hatje Cantz.

The 18th-Century Passion for Botany: Illustrations

3 Gessner Triandria

Illustration of Linnaeus’s triandria class (Table IV) from Johannes Gessner’s Tabulae phytographicae, Biodiversity Heritage Library

In discussing 18th century botany, it’s impossible not to bring up Carl Linnaeus.  As I’ve already discussed (1, 2), his classification system based on flower structure made it easier to identify species.  It also changed the character of botanical illustrations, as noted in an earlier post on Linnaeus’s collaboration with the artist Georg Ehret during their time together at George Clifford’s estate in the Netherlands.  Ehret had already been schooled in the necessity for accuracy and detail by the exacting German botanist Christoph Jacob Trew, but Linnaeus introduced him to a classification system based on the number of male and female parts in a flower.  In many plants, these structures are difficult to see without a magnifying glass or without dissecting the flower.  So while small drawings of such features sometimes appeared at the bottom of botanical illustrations before this time, they then became more common (Nickelsen, 2006).  Also, there was more emphasis on the flower in the main drawing as well.  At times this attention was coupled with less detail on the non-reproductive parts of the plants.  For example, the branch and at least some of the leaves would be just outlines in ink drawings where only the flower was colored.  There were also cases, as in Johannes Gessner’s Tabulae phytographicae (1795-1804), where flowers and fruits were presented with almost no attention to other plant parts (see figure above).

Linnaeus’s work also had the far reaching effect of making botany more popular and thus increasing demand for botanical publications in a variety of formats, most calling for illustrations, again of various sorts.  There were richly illustrated florilegia that emphasized the beauty of plants growing in a particular area, or even in a particular garden.  Usually these had engravings hand-colored on fine paper and produced in small print runs.  More technical books tended to have uncolored illustrations; many botanists thought that color distracted the eye from the structural elements that were important in identifying species.  Toward the end of the century the thirst for botanical publications led to William Curtis’s first issue of the Botanical Magazine which became a long-running journal known for its hand-colored illustrations.  Some of the early ones were done by William Kilburn who then went on to a long career in producing gorgeous botanically themed wallpapers and fabrics, harkening back to the floral embroideries discussed in the last post (Christie, 2011).  After Kilburn, James Sowerby took over (Henderson, 2015).  This was early in his illustrious career as a natural history artist.  Sowerby then teamed up with James Edward Smith, the purchaser of Linnaeus’s herbarium and founder of the Linnean Society, to begin a long-running series of books on English Botany.  These were printed in a small format making them accessible to many interested in botany, yet Smith’s plant descriptions was written with accuracy so they were considered valuable references.  Distinguished gardeners began sending rare plants to Sowerby to use in his paintings, thus adding prestige to their horticultural abilities and all this indicating the continuing passion for plants.

This trend wasn’t just in Britain.  I’ve already mentioned Ehret’s art in Trew’s botanical publications in German, while in France, the center of botanical activity was at the King’s Garden, the Jardin des Plantes, in Paris.  From 1666 to the French Revolution in 1789, there was a full-time artist working at the garden, beginning with Nicolas Robert and including Claude Aubriet who created impressive work for Joseph Pitton de Tournefort’s book on the plants of the Middle East, Aubriet having traveled with the botanist on this voyage; he also illustrated other work by Tournefort.  He was succeeded by his student, Madeleine Basseporte, one of a growing number of women distinguishing themselves as botanical artists.  Finally, there was Gérard van Spaendonck who survived the revolution, was later honored by Napoleon, and taught Pierre-Joseph Redouté, whom many consider the greatest flower painter of all time.

One further aspect of 18th century botanical art to consider is the trend, already mentioned in the case of Aubriet and Tournefort, to include artists along with naturalists on expeditions to little known parts of the world.  When James Cook sailed on his first round-the-world voyage, Joseph Banks and Linnaeus’s student Daniel Solander collected and described plant specimens, and the artist Sydney Parkinson created over 900 drawings of them (Banks et al., 1980).  The ill-fated expedition headed by Jean-François La Pérouse had a similar team as did the voyage of Antoine Bruni d’Entrecasteaux who was sent in search of his missing countrymen (Williams, 2003).  There were also a number of Spanish enterprises, most to Latin America toward the end of the 18th century (Bleichmar, 2011).  It is interesting that many of the expeditions resulted in no publications or extremely delayed ones.  Banks’s planned flora of Australia wasn’t published until the 1980s, and much of the Spanish material was never published by members of the expeditions, though the superb illustrations produced by the artists employed by José Celestino Mutis in New Granada are now available on a well-organized website.  The 18th century was definitely a century when botanical art flourished, feeding the passion for botany and also for floral decorative art in what could be considered a self-perpetuating circle of influence.  In the next post, I’ll look at some of the philosophical ramifications of these trends.


Banks, J., Solander, D., & Cook, J. (1980). Banks’ Florilegium (Vols. 1–34). London, UK: British Museum.

Bleichmar, D. (2011). Visible Empire: Botanical Expeditions and Visual Culture in the Hispanic Enlightenment. Chicago, IL: University of Chicago Press.

Calman, G. (1977). Ehret: Flower Painter Extraordinary. Oxford, UK: Phaidon.

Christie, A. (2011). A taste for seaweed: William Kilburn’s late eighteenth-century designs for printed cottons. Journal of Design History, 24(4), 299–314.

Henderson, P. (2015). James Sowerby: The Enlightenment’s Natural Historian. Kew, UK: Royal Botanic Gardens, Kew.

Nickelsen, K. (2006). Draughtsmen, Botanists and Nature: The Construction of Eighteenth-Century Botanical Illustrations. Dordrecht, The Netherlands: Springer.

Williams, R. L. (2003). French Botany in the Enlightenment: The Ill-Fated Voyages of La Perouse and his Rescuers. Dordrecht, The Netherlands: Kluwer.

The 18th-Century Passion for Botany: Women

2a Passiflora laurifolia

Paper cutout of Passiflora laurifolia by Mary Delany, in the collection of the British Museum

The last post was on the enthusiasm for gardening that flourished in the 18th century.  One aspect of this trend was the increasing interest in horticulture among women, especially those with the wealth to satisfy it.  A prominent example was Margaret Bentinck, Duchess of Portland (1715-1785).  She was curious about all aspects of natural history and was an prodigious collector not only of animals, plants, and minerals, but also of paintings and the decorative arts.  After her husband’s death in 1762, she devoted more time to bringing exotic plants to the gardens of her estate at Bulstrode Park and learning as much as she could about natural history.  She had impressive collections in conchology, entomology, and ornithology, but I’ll concentrate on the plants.  Bentinck knew Peter Collinson (see last post) and received North American plants from him.  He also suggested that she hire Daniel Solander, Carl Linnaeus’s former student who had recently arrived from Sweden, to arrange her collections according to the Linnaean system.  She may have had massive numbers of organisms, but unlike many other collectors, they were well-organized (Laird, 2015).

Bentinck also hired another émigré, the botanical artist Georg Ehret, not only to paint plants she grew, but also to teach art to her daughters.  Another member of her household was the Reverend John Lightfoot, who served as chaplain and naturalist, giving special attention to her shells and plants.  She financed his collecting in various parts of Britain and took botany lessons from him.  The duchess was obviously more than just a plant lover; she had a sophisticated appreciation of botany, and not surprisingly, kept a herbarium.  In fact, none other than the French philosopher, Jean-Jacques Rousseau, gave her two portable herbaria.  As I’ll discuss in the last post in this series, he became passionate about botany toward the end of his life, had a herbarium, and created others for patrons such as the Duchess, whom he visited while in England in 1767.

Bentinck was not the only woman with broad intellectual pursuits.  She was loosely connected with the original group of bluestockings, who met to discuss their mutual intellectual interests.  She was particularly close to another member, Mary Delany, also a gardening enthusiast whose knowledge of botany deepened with time.  Delany came from a less wealthy line of nobility, but this still gave her access to royal circles.  She had a dreadful first marriage, and eventually found love and contentment with an Irish clergyman and friend of Jonathan Swift’s.  She developed their garden near Dublin and led a satisfying life until the Rev. Delany’s death in 1768.  Like many women of her time, she took an interest in drawing, and combined with her gardening passion, it’s not surprising that she drew flowers.  Among her accomplishments was the design of floral embroidery patterns including those used on a gown she wore when presented at court.  Though she did needlework, the gown was made by professional embroiderers and precisely displayed about 200 identifiable species (see image below).  It was so magnificent that portions were preserved and passed down through her family for generations (Hayden, 1994).

2b Delany mantua

Segment of the embroidered court gown designed by Mary Delany

After her husband’s death, Delany spent months at a time visiting Bulstrode Park, working with the Duchess on her plant collections and studying with Rev. Lightfoot.  They would press plants, draw them, and dissect them using a microscope, another not uncommon aspect of botanical interest at the time.  Naturally, they also walked through the gardens regularly, but in 1772, Delany had a sore foot that kept her sidelined.  She occupied her time by coloring pieces of paper and then cutting them out to form pictures of flowers.  These were very much in the tradition of botanical illustrations: a single branch against a plain background, though instead of the usual white, she used black.  They could be likened to herbarium specimens, having more depth and texture than an illustration does.  There are even a couple of cases where she added real leaves to a work.  Delany, and presumably the Duchess, were pleased with her compositions, and so she continued.  Over time the pieces became more elaborate.  At first, she would paint in details, but later she cut out tiny pieces of paper to form minute structures.  One particularly amazing example was used on the cover of a catalogue for an exhibition on Mrs. Delany and Her Circle (Laird & Weisberg-Roberts, 2009).  It presents the passionflower, Passiflora, in all its glory (see figure at top).

During the next 10 years Delaney completed over 900 cutouts, with the Linnaean name for each species written on the back.  When King George III and his wife Queen Charlotte, another devoted gardener, visited Bulstrode, they marveled at Delany’s work and within months she was given access to plants at Kew Gardens.  There the King’s confidante, Joseph Banks, was converting the garden to the study of exotic species.  Delany also received plants from a number of other sources, including the Quaker gardener John Fothergill, a patron of the American nurseryman John Bartram, and William Pitcairn, who sponsored plant collecting in the East and West Indies (Laird, 2015).  Her work is a notable example of how women combined botanical knowledge with the arts.  The next post will focus on the artwork resulting from the passion for plants in the 18th century.


Hayden, R. (1993). Mrs. Delany: Her Life and Her Flowers. New York: New Amsterdam.

Henderson, P. (2015). James Sowerby: The Enlightenment’s Natural Historian. Kew, UK: Royal Botanic Gardens, Kew.

Laird, M. (2015). A Natural History of English Gardening 1650-1800. New Haven, CT: Yale University Press.

Laird, M., & Weisberg-Roberts, A. (2009). Mrs. Delany and Her Circle. New Haven, CT: Yale University Press.