This and That: Art and Science

4 McMahon and Case

“Layered Similarity,” print created by Taryn McMahon and Andrea Case of Kent State University

I cannot end my series of miscellaneous posts (1,2,3) without mentioning one of my favorite topics: the relationship between art and botany.  The example I want to explore here comes from a Kent State University blog post.  This institution has an Environmental Science and Design Research Initiative (ESDRI), an intriguing title for a collaboration among individuals from across the university who are interested in connections between the built and natural worlds.  One participant is Taryn McMahon, an assistant professor of print media and photography.  Concerned with plants and ecology, she was looking for someone with similar interests and was led to Andrea Case, an associate professor of biology doing research on plant reproduction.  I know from experience that individuals who share common interests but are sequestered in different colleges at a university may never find each other.  That’s why an interdisciplinary enterprise like ESDRI is so important:  it makes these links more likely to form.

McMahon was seeking to understand plants more deeply for a print-making project called “Intersecting Methods” curated by Matthew McLoughlin, a Maryland artist.  Every two years he invites a number of printmakers to each submit a piece made in collaboration with a scientist for a portfolio that is exhibited and then each participant receives a set of all the prints.  There is a website where you can see some of the earlier series.  In the course of their collaboration, McMahon and Case discussed their research interests and processes.  They came to appreciate how each approached the ideas they found intriguing.  Case, curator of the Kent State Herbarium, showed McMahon specimens to emphasize that small details in plant structure matter in terms of identification and in how plants function.  McMahon in turn was struck by the fact that her prints were about the same size as herbarium sheets and also, the plants in her prints were arranged very much like specimens as well.

There are also similarities between the working methods of print makers and scientists.  Both start with an initial idea, question, or problem to solve, then experiment to find the right techniques, refine them as they go based on experimentation, do more experiments or make more prints after changing variables, and keep doing this until they come to a final result with which they are satisfied enough to make it public.  Since Case does research on the genus Lobelia, she and McMahon decided to use plants she was growing in making the prints, work which they did together.

What I find most interesting about this collaboration is how the interests of artist and botanist coincided.  Not surprisingly, they both emphasize the importance of observation.  Case mentioned the need to be meticulous in documenting and observing plants.  McMahon noted that a drawing starts with staring at the subject and understanding it; drawing comes only after understanding the form.  One of her most important influences is the 17th-century Dutch artist Maria Sibylla Merian, known for her paintings of insects and plants.  McMahon’s work is very different but it shares Merian’s bold graphic style.  The artist also quoted the philosopher of science Bruno Latour (2004), who argues that matters of fact for scientists can become matters of concern through art.

This is a beautiful and powerful idea.  It says a great deal about both endeavors and speaks of a potent feedback loop between them.  Art makes us look more carefully and feel more deeply, in this case, reaching a different level of understanding of the plant world as a source of color and form.  This experience can make us more willing to look carefully at the plants we encounter.  Looking often leads to questioning:  why are the leaves hairy or the stems sticky or the flowers vividly colored?  Looking more makes the plants in our environment more important to us.  I know this for a fact.  Since I’ve become plant-mad, I see so much more, examine so much more, and am amply rewarded with new knowledge and new questions to answer.

McMahon also sees the scientific viewpoint in dialogue with the art:  asking questions about its meaning and its impact.  Obviously her practice and Case’s are now in conversation with each other, and I hope they will continue their collaboration in the future.  It could lead to a mutual enrichment of their respective projects, and also, perhaps most importantly, enrich their students’ learning experiences, so that the next generation will think of art and science as more closely and inextricably connected than was the case in the 20th century.  The print that the two professors produced together is called “Layered Similarity” (see above).  Bringing my own interpretation to it, as McMahon has invited, I see the dark silhouettes in the foreground as the pressed herbarium specimens and the colored forms bursting behind them as the living plants ready to jump from the page, full of life and in bloom.  Yet they too have a hint of being specimens as well, note the insect damage to the leaves.  These are plants that have been captured in the middle of their lives, warts and all—a disembodied leaf may suggest that its reverse side is being displayed.  There are both literally and figuratively many layers to this print, and if you look at McLaughlin’s site you’ll see prints from other scientist/artist collaborations that all reward careful observation.

Reference

Latour, B. (2004). Why Has Critique Run out of Steam? From Matters of Fact to Matters of Concern. Critical Inquiry, 30(2), 225–248. https://doi.org/10.1086/421123

This and That: Remnants

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Pointed rush, Juncus oxymeris, collected in 1889 by Scottish-American doctor and botanist Anstruther Davidson in the herbarium of the California Botanic Garden.

In a recent post, I wrote about the California Phenology Project aimed at organizing and adding phenology data to online specimens in the Consortium of California Herbaria.  Project activities include a blog, ReCAP, with items that feature interesting specimens, including a piece entitled “What Specimens Reveal about LA History.”  The specimen highlighted was a pointed rush, Juncus oxymeris, collected in 1899 by Anstruther Davidson (1860-1932).  A Scottish physician who had emigrated to California and taught dermatology at the University of Southern California, Davidson was also an amateur botanist and entomologist.  He collected throughout the area and also spent time studying the plants of Arizona.  He contributed many articles to the Bulletin of the Southern California Academy of Sciences and wrote a Catalogue of the Plants of Los Angeles County in 1896.

The Juncus Davidson collected favors a wetland habitat, which at one time was abundant in the Los Angeles basin, with water flowing from the Los Angeles and San Gabriel Rivers into the Pacific.  These waterways have since been tamed and the wetlands drained.  Juncus oxymeris hasn’t been found in this area for a century, though specimens were collected in the 1920s and 1930s in neighboring Orange County.  This example is a powerful reminder of what Los Angeles used to be like and joins many other specimens in linking us to the past.  When I visited the herbarium at the Brooklyn Botanical Garden in 2011, when there was a herbarium at BBG, the curator Kerry Barringer showed me orchids collected on the south shore of Long Island, a few minutes from where I lived.  One was from the area where Aqueduct Racetrack now stands, and another from what is now JFK Airport.  I remember this experience vividly.  It was early in my herbarium obsession and caused a collage of images to flash through my mind:  jets taking off, the smell of jet fuel in the air, and delicate orchids in a wetland—a disturbing juxtaposition.  I had a similar experience years earlier on a visit to the Bell Museum of Natural History in Minneapolis where one of their amazing dioramas portrayed a wetland scene full of birds, and with an explanatory text noting that the area depicted became the site of the Mall of America.

Kathryn Mauz, the author of An Agreeable Landscape: Historical Botany and Plant Biodiversity of a Sonoran Desert Bottomland, 1855-1920, describes another landscape, like most in the world, that has changed considerably over the past century.  The book’s frontispiece is striking (see above).  It is a photo montage of plates included in the book.  The background is a photo of the Cienega Creek Natural Preserve and onto this are placed historic specimens of the plants that used to be found there; it is, in a sense, a visual representation of  the habitat loss scenarios represented by the Juncus and orchid stories.  Here is a place that represents in the present day what is found in herbarium cabinets.

Another example also comes to mind.  Again, once close to my former home on Long Island.  In an area that includes a sports arena, a large mall, and two colleges, there are a few remnant acres of the Hempstead Plains that used to cover 38,000 acres of the island.  Adjacent to the local community college, the site managed to be preserved just as the rest of the area was being developed because it was, and is, home to a number of rare plants.  The preserve isn’t large enough for a visitor to forget adjacent urbanization, but still, it’s a refuge for plants, animals, and humans, one of many havens throughout the country that are small, damaged, and yet steadfast reminders of the landscapes of the past.

Preserving the land is meaningful in a way that a stack of herbarium sheets can never be, yet we need specimens both in documenting what is lost and what has been saved.  Works like Davidson’s Catalogue also contribute to this effort in recording what once flourished in what is now a botanically impoverished area.  One of his articles provides some context for the transformation.  Written in 1907, “Changes in Our Weeds” is a follow-up to an article he had published 14 years earlier on “immigrant” plants in Los Angeles county, an interesting term for a person to use who was himself an immigrant.  Davidson summed up his findings:  “None of those then observed have become extinct:  the relative frequency of the majority have remained unchanged.  Some have increased in numbers, and a few new ones have appeared” (p. 11).  Among the latter was Lactuca serriola, prickly lettuce, a European species.  He found it at one location in 1896, as a fellow botanist did in another area.  “Since that time it has spread so rapidly that it may now be considered the most troublesome weed in this district” (p. 12).  When cows ate it, their milk had a sour taste, but he balanced this observation with one on how chickens and turkeys were fond of it.  There are, of course, endless stories like this about non-natives from around the world, but sometimes it’s good to focus on just one of them, as was done in the blog post that triggered this stream of consciousness post.

References

Davidson, A. (1905). Changes in our weeds. Bulletin of the Southern California Academy of Sciences, 4, 11–12.

Mauz, K. (2011). An Agreeable Landscape: Historical Botany and Plant Biodiversity of a Sonoran Desert Bottomland, 1855-1920. Fort Worth, TX: BRIT Press.

This and That: Travels of Sophora toromiro

2 Sophora

Toromiro, Sophora toromiro (Phil.) Skottsb, collected 28 June 1800, H. Herrenhus. [possibly Hannover Herrenhausen Royal Gardens], Germany. CC BY-NC-ND 4.0. Te Papa (SP107845)

As with most of the posts in this series of miscellanea (see last post), this story begins with a Tweet, one linked to a blog post and a research article connecting four countries over 250 years.  I’ll try to keep it as simple as possible, by starting in the middle.  In 1877, James Hector, director of the Colonial Museum in New Zealand (now the Museum of New Zealand: Te Papa), asked the British Museum (BM) for a collection of European plant specimens to compare with European plants colonists had brought into the country and were now flourishing, sometimes to the point of being nuisances.  Hector received 28,000 specimens collected by three British amateur botanists: a husband and wife, Silvanus and Bridget Thompson, and Thompson’s student, James Baker.  Most specimens were from cultivated plants gathered in German botanic gardens and the Cels nursery in France between 1764-1864.  Hector never got around to sorting through this gift from the BM; it remained in its original packaging until the 1950s; even today, the only vascular plants to be processed are the orchids.

Recently six specimens of Sophora were found in the collection.  Sophora is a small genus of 17 species in the Fabaceae family and native to the South Pacific.  With eight species, New Zealand is its center of diversity, hence the interest in these sheets that were dated from 1796 to 1822 and were presumably from cultivated plants.  This was surprisingly early for Sophora to be growing in Europe.  Until now, it was thought that the Sophora in Europe were all descended from seeds collected from the 1920-1950s.  There was little plant collecting in the South Pacific until the early 1800s, though Joseph Banks and Daniel Solander had gathered seeds of two Sophora species on Captain James Cook’s first round-the world voyage.  These were planted at Kew by 1772, and there were a few other early cultivations.

The six specimens of interest are in the herbarium of the descendent of the Colonial Museum, the Museum of New Zealand, with the Maori name, Te PapaCarlos Lehnebach, botany curator, and Lara Shepherd, research scientist specializing in DNA sequencing, decided to learn more about the genetics of these six specimens from the 19th-century BM gift.  When Shepherd got the results of her analysis, she was shocked:  one of the specimens, collected in 1800, had genes of Sophora toromiro, a species endemic to Easter Island, Rapa Nui.  It became extinct in the wild in the 20th century, though it is cultivated at several botanic gardens.  At first Shepherd couldn’t believe the results, but when she and Lehnebach looked at the specimen, they found that it did in fact have characteristics of the Rapa Nui plant.  But how did it end up growing in Germany in 1800?

The researchers speculate that seeds may have been collected during Captain Cook’s second round-the-world voyage (1772-1775), when the expedition stopped at Rapa Nui.  The botanists on that trip were Johann Reinhold Forster and his son Georg, with the Linnaean pupil Anders Sparrman as their assistant.   They were the first Europeans to collect specimens on the island, and Sparrman was known to have collected seeds.  He may very well have collected them from this plant, since it grew in thickets and was the only native shrub on the island.  If S. toromiro seeds were planted in the late 1770s, then the shrub would have been established enough to yield cuttings in 1800.  In looking for other Sophora specimens, Lehnebach and Shepherd have found one at the herbarium of the Botanic Garden and Botanical Museum Berlin-Dahlem that could be S. toromiro.  It has no collection date, but it is part of Carl Ludwig Willdenow’s (1765-1812) collection, and a large number of Forster specimens were included in it.  Willdenow had one of those bad habits that frustrates later curators:  he removed the old labels and replaced them with his own, often neglecting to transcribe what’s now considered essential information.

Admittedly, there are suppositions holding this story together, but further work, including analysis of chromosomal DNA from the Willdenow specimen, may make the picture clearer.  In any event, this case study presents a good argument for curating specimens that have been moldering in boxes for decades if not centuries.  This situation is not the result of bad management but of overworked curators without time to deal with the substantial work involved in mounting specimens and providing them with up-to-date identifications.  However, this example suggests the exhilaration that can result from the effort.  Though not every find is a jewel, that’s true of cleaning out any attic.  However, one never knows when a first edition book or a valuable art work might come to light.  My favorite statistic at the moment is that when the herbarium at the National Museum of Natural History in Paris was cleared out prior to renovations about 10 years ago, 830,000 unmounted specimens were found.  Most of them have since been mounted by an outside contractor called in for the massive job (Le Bras, 2017).  But the specimens still need to be curated and filed, a job that amounts to organizing a good-sized herbarium.

Reference

Le Bras, G., Pignal, M., Jeanson, M. L., Muller, S., Aupic, C., Carré, B., Flament, G., Gaudeul, M., Gonçalves, C., Invernón, V. R., Jabbour, F., Lerat, E., Lowry, P. P., Offroy, B., Pimparé, E. P., Poncy, O., Rouhan, G., & Haevermans, T. (2017). The French Muséum national d’histoire naturelle vascular plant herbarium collection dataset. Scientific Data, 4(1), 1–16. https://doi.org/10.1038/sdata.2017.16

This and That: Ehrenberg’s Diatoms

1a Diatoms

Images from E. César’s Tweet on the Ehrenberg Collection at the Museum für Naturkunde in Berlin.

Though I have more time to think deeply right now than ever in my life, I’m finding it difficult to do; everything is so different from usual that it’s unsettling.  That’s why I’m not focusing on one topic for a month’s worth of posts as I usually do, but flitting from one topic to another from week to week.  In part this is because of Twitter, my lifeline to the botanical world at the moment.  Thank goodness botanists are interesting people and post interesting ideas.  Most days I find at least one item worth bookmarking and then delving into more deeply.  That’s how I discovered Christian Gottfried Ehrenberg (1795-1876).  I must have come across his name in the past, especially when I was reading about Alexander von Humboldt because Ehrenberg accompanied the explorer on his trip to Siberia in 1829.

A Tweet on Ehrenberg by Edgley César, curator of diatoms at the Natural History Museum, London, included the image above.  It was the photo on the upper right that first caught my eye—obviously old data—and the illustration on the lower left was another lure.  César took the pictures at the Museum für Naturkunde in Berlin where he had spent a week examining specimens of a genus Ehrenberg had described and was amazed by how much work this “founding father” of diatom research had done and how well he drew.  As the thread continued, someone asked about Ehrenberg and César pointed them, and me, to a series of papers published in 1998 dealing with his life, work, and collections.

Ehrenberg was definitely productive throughout his life.  Born near Leipzig, he attended the university there, completing his doctorate on fungi in 1818.  His fungal herbarium is in the Botanic Garden and Botanical Museum Berlin-Dahlem.  From 1820-1825, Ehrenberg participated in an expedition to the Middle East, during which he and his friend Wilhelm Hemprich amassed 114 boxes with 46,000 plant and 34,000 animals specimens as well as seeds, fossils, minerals, and of course, mummies.  Yet the trip was grueling, with three-quarters of team dying, including Hemprich.  Ehrenberg published, Symbolae Physicae, a multivolume work on all aspects of the collection and including 800 plates, many based on his drawings.  He did not describe many of the plants he collected and left the world of higher plants to concentrate on microscopic work, on what were called infusoria, organisms found in decaying matter.  However, he did teach all his children to press plants and create their own herbaria.

A great deal of Ehrenberg’s research was on radiolaria and diatoms.  He considered them all tiny animals and carefully studied their internal structures, which he interpreted as digestive, reproductive, and muscular.  He thought that when better microscopes were developed, these organelles would be seen more clearly.  It is interesting that when diatoms were finally recognized to be more closely related to plants than animals, interest in their internal structures waned, and their taxonomy became based primarily on their elaborate silicate shells that come in a dizzying array of patterns.  The assumption became that there was little difference among these organisms internally; plant cell structures were just not that interesting.  Ancient shells found in diatomaceous earth have long been used in geological exploration, since they are related to oil deposits, but even present-day species are often dried, and just their shells examined.

Ehrenberg made extremely detailed and exquisite illustrations of these organisms and in 1838 published a book with 64 plates on Infusoria in all of their complexity.  He also kept detailed notes on his work, as well as retaining the specimens he’d examined.  Glass slides and coverslips were expensive, so he used small mica discs with a bit of Canadian balsam, a shorthand term for a thick liquid made from the tree’s resin that was a mainstay for 19th-century microscopists because of its optical properties.  Ehrenberg highlighted interesting organisms with small circles, and then with a little more balsam, stuck the discs to his notes.  These have been preserved for almost 200 years, though not without difficulties.

The Ehrenberg Collection at the Museum für Naturkunde consists of 40,000 microscope preparations, 5,000 raw samples, 3000 illustrations, and 800 letters.  It is the combination of different kinds of information that makes it so impressive and valuable, but also daunting.  Most of Ehrenberg’s vascular plant herbarium was at the Berlin-Dahlem botanic garden and was lost when its herbarium was bombed during World War II.  The infusoria, on the other hand, were at the museum and survived but in what would become East Berlin.  The collection was not curated or organized until after German reunification when new resources became available.  It was in light of this that the 1998 article collection was published to showcase Ehrenberg’s work and how the collection could be used, just as César is now using it.  The notes are now beautifully curated (see below), but this required a great deal of work.  The balsam has become brittle, and the mica discs are fragile and difficult to handle.  Over the years some had become unstuck, shifted, and were crushed.  Conservation was necessary because the records contain many type specimens, though as David Mann notes in the last article in the collection, types can present difficulties in terms of hunting them down in a compilation this vast and with all the vagaries it has been through.

1 Conserved

Photo of portion of conserved Ehrenberg Collection at the Museum für Naturkunde in Berlin.

As someone who is fascinated by diatoms, the Ehrenberg Collection is definitely a treasure (see video), along with the diatom collections at the Academy of Natural Sciences herbarium in Philadelphia (see earlier post) and at the Natural History Museum, London.  If you are interested in these beautiful organisms that are classified as algae, you might want to look at Martyn Kelley’s long-running Microscopes and Monsters blog where he deals with microscopic algae and environmental monitoring.

Botanists in South Carolina: Francis Peyre Porcher

 

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Title page of Francis Peyre Porcher’s Resources of the Southern Fields and Forests from the Biodiversity Heritage Library

Francis Peyre Porcher (1824-1895) was born on his grandfather’s plantation in St. John’s Berkeley outside of Charleston in 1824.  His great-grandfather was Thomas Walter, a Charleston businessman, plantation owner, and botanist who wrote Flora Caroliniana (1788), the first flora of a North American region using Linnaean classification (see earlier post).  Porcher’s parents were also interested in botany.  His father, a Charleston physician, died when he was eight years old.  This left his wife to manage their plantation and raise six children, yet she still found time to satisfy her interest in plants.  Porcher often went botanizing with his mother and uncle.  They were sometimes accompanied by Henry Ravenel, a young man from a neighboring plantation who also had an interest in botany (see last post).  He was ten years older than Porcher, and they remained lifelong friends even after Ravenel moved to Aiken in western South Carolina (Haygood, 1987).

Porcher went to South Carolina College and then to South Carolina Medical College, graduating in 1847.  His thesis, “A Medico Botanical Catalogue of the Plants and Ferns of St. John’s Berkeley, S.C.,” was considered so valuable it was published by the College.  Two years later, this became the basis for his Sketch of the Medical Botany of South Carolina (1849); Henry Ravenel had assisted him on this project.  After graduation, Porcher studied in Europe for over two years at leading medical institutions in France and Italy.  Then he returned to Charleston, where he partnered with Dr. Julian John Chisholm in a practice that included treating the slaves of wealthy plantation owners, many of whom Porcher knew through his family’s plantation (Townsend, 1939).

Since slaves were property, owners wanted to keep them in good health, so it paid them to seek expert care when needed.  In 1855, Porcher and Chisholm founded a hospital for treating enslaved people, since there had never been such a facility in Charleston.  Porcher and Chisholm were being less humanitarians than smart businessmen in establishing a separate medical facility, one that could provide services for difficult cases.  Porcher also visited plantation infirmaries, which were effective for many of the health needs of the enslaved and were usually staffed by enslaved women with expertise in herbal medicine.

When the Civil War began Porcher joined the Confederate medical corps serving first in South Carolina and then at Fort Nelson in Portsmouth, VA where he was stationed until the area was taken by Union troops.  Then the Confederate Surgeon-General, Samuel P. Moore, granted Porcher leave to complete what became Resources of the Southern Fields and Forests in support of the war effort.  Moore had originally asked Porcher to write the book at the beginning of the war, but as the Confederacy’s situation deteriorated, the book was more urgently needed.  Because of his previous publications on South Carolina plants and his medical experience before and during the war, Porcher had already laid the foundations for this text. Besides his own botanico-medical expertise, Porcher had another key advantage in preparing his manuscript:  his life on plantations and his treatment of slaves gave him access to the knowledge of enslaved healers.

Martia Graham Goodson (1987) begins her article on the medical-botanical contributions of African enslaved women to American medicine:  “That the daughters of Africa were a rich source of medical knowledge was not lost on the professional doctors of the Slave South, whose livelihood came from tending sick slaves” (p. 198).  She uses Francis Porcher as an example, noting his sophisticated medical background, including his European studies.  She argues that his education in materia medica began on the plantation where he grew up and depended on his contact with enslaved women working in plantation infirmaries.  For many entries in Resources Porcher mentions how particular species were used by enslaved healers, though no one is referred to by name.  As Goodson notes:  “’Used extensively’ by ‘the negroes’ is a phrase that permeates Porcher’s descriptions of the medical wealth of the plants of his native state.  In fact, nearly one-third of the plants are described as being ‘used extensively on the plantations’ or ‘used by the negroes’ or ‘used in domestic practice’” (p. 200).

Porcher’s 600-page text was published in 1863.  He often went into great detail describing where and when a particular plant was likely to be found, how it should be harvested, and not only what it could be used for, but how it should be prepared for use.  From the number of plants mentioned as valuable in producing soap, curing diarrhea, and treating fever these were obviously critical needs—and very basic ones.  This book was not just for the military, though it was distributed to all Confederate physicians.  Since the South could no longer rely on the Northern states or foreign trade for the medicines and other goods they needed, everyone had to become self-sufficient and utilize local resources as much as possible.

In a sense, Porcher was attempting to make all Southerners practical botanists who could maximize their use of what was available to them, even if they hadn’t hitherto paid much attention to plants in the past.  The book remained popular and was reprinted after the war, when Porcher returned to his medical practice.  Though life in Charleston was difficult as it was throughout the South, he had a needed expertise, a good reputation in his practice, and social connections that still counted for something, with many of these extending well beyond the South because of his service in the American Medical Association.  He resumed teaching at the Medical College, did research on yellow fever, and died in Charleston in 1895.

References

Goodson, M. G. (1980). African Slave Contributions to Medicine. The Western Journal of Black Studies, 11(4), 198–203.

Townsend, J. F. (1939). Francis Peyre Porcher, M.D. (1824-1895). Annals of Medical History, 1, 177–188.

Note: I want to thank Herrick Brown and Lauren LaFauci for discussions on Francis Porcher that were very helpful to me.  Also, I am grateful for the assistance I received in assessing the Porcher papers at the South Caroliniana Libary at the University of South Carolina, Columbia.

Botanists in South Carolina: Henry Ravenel

 

3 Limnobium spongia copy

Specimen of Limnobium spongia from the Ravenel Herbarium at the A.C. Moore Herbarium, University of South Carolina, Columbia

Henry Ravenel was born in 1814 in an area outside Charleston that had been settled by French Huguenots in the 17th century.  They had fled religious persecutions by Catholics in France.  Many had first gone to Protestant England and then sought greater freedom and economic advantage in the British Colonies.  The Ravenels were plantation owners and had the money to send their son to a nearby academy and then to South Carolina College, now the University of South Carolina, Columbia, where he received his degree and where his herbarium resides.  While he was always interested in plants and went botanizing with those similarly inclined on nearby plantations, he did not go into medicine, as did others of that time with a botanical bent.  Instead he took up plantation life, inheriting land from his father.

Ravenel also pursued his study of botany, collecting specimens, seeking information from such experts as Asa Gray, Edward Tuckerman, and George Engelmann, and eventually becoming particularly interested in cryptogams.  When William Henry Harvey, the British botanist, was in Charleston on a lecture tour in 1849, he met Ravenel and was impressed by his knowledge.  Writing to William Jackson Hooker afterwards, Harvey bemoaned the fact that Ravenel was moving away from studying vascular plants and focusing on fungi.  Ravenel and Moses Ashley Curtis, a North Carolina clergyman/botanist decided to collect specimens for a fungal exsiccati.  Curtis eventually bowed out of the project, but continued to provide assistance, and Ravenel eventually published five volumes of Fungi Caroliniani Exsiccati between 1852 and 1860.  He also contributed to Fungi Americani Exsiccati (1872-1880) along with the British mycologist M. C. Cooke.

In 1853, Ravenel made a major change, selling his plantation and moving his family to a farm in Aiken, South Carolina, just east of the border with Georgia, near Augusta (Haywood, 1987).  He hoped the change to a drier and somewhat cooler area would improve his failing health.  Perhaps he also hoped that the land would be healthier too, because as early as 1843 he had banded together with other low country farmers to form an agricultural society to investigate ways of improving the diminishing fertility of their plantations.  His new property, Hampton Hill, provided him with a good income from the peach trees and grape vines he planted that were tended by about 80 slaves.  Then the Civil War changed everything.

One reason there is so much known about Ravenel’s life is that, besides the evidence of his broad correspondence with John Torrey, Asa Gray, and others, he kept a diary from 1859 until his death in 1887.  An edited version was published by Arney Childs (1947), a history professor at the University of South Carolina.  It is a fascinating book for someone like myself who is trying to learn Southern and botanical history at the same time.  Ravenel began with several entries on family and visiting relatives for Christmas, and on December 31, 1859 he decided “to record a few words upon political affairs. . . .  The future is now wrapped in uncertainty” (p. 4).

After war was declared Ravenel put nearly all his money into Confederate war bonds, something that was common among Southerners with means.  They saw it as a way to ensure the victory of their cause.  Since the bonds proved worthless, the ultimate outcome for Ravenel and many others was no financial reserve to fall back on after the war.  Fruits like peaches and grapes became luxury items in the South and were difficult to ship to Northern markets.  Ravenel sought several times to sell his land, but repeatedly turned down offers that were far below what the land had been worth before the war.  Eventually he did sell it for less than half what he had been offered right after the war.

He turned to botany as a way to earn some money, arranging to collect for others and also to write for agricultural and botanical publications.  He sold his botany books, many of them precious like 12 volumes of de Candolles’s Prodromus that netted $40.  He also eventually sold his microscope and the remaining issues of his exsiccati that he had.  He was pleased that his northern correspondents got in touch as soon as communication became possible, and he asked Gray for advice on starting a nursery.  When he put the same question to Philadelphia nurseryman Thomas Meehan, he received seeds and cuttings as a gift, and later a $50 “loan” that Meehan made clear didn’t have to repaid.  Ravenel’s friend from his youth, Dr. Francis Peyre Porcher, who is the subject of the next post, tried to find employment for him in Charleston but there just wasn’t anything to be had.  This is when Ravenel wrote in his diary that he regretted not having had enough resolve to go into medicine.

Through all this he continued to collect, but after his death his widow had a hard time selling his herbarium for what she considered its worth.  She ended up splitting it, with the cryptogams going to the British Museum (now the Natural History Museum, London).  A Ravenel relative bought the vascular plant collection and gave it to Converse College in Spartanburg, SC.  Eventually, the college transferred it on permanent loan to the A.C. Moore Herbarium at the University of South Carolina, Columbia, where it has been carefully curated and digitized.  The herbarium also collaborated with other university departments in the digital humanities project, Henry Ravenel: Plants and Planter, producing a website where Ravenel’s correspondence, journals, and specimens are all available and searchable.

References

Childs, A. R. (Ed.). (1947). The Private Journal of Henry William Ravenel 1859-1887). University of South Carolina Press.

Haygood, T. M. (1987). Henry William Ravenel, 1814-1887: South Carolina Scientist in the Civil War Era. University of Alabama Press.

Note:  I want to thank John Nelson and Herrick Brown of the A.C. Moore Herbarium at the University of South Carolina, Columbia for introducing me to the world of Henry Ravenel, teaching me so much about him, and helping me to decipher his handwriting.

Botanists in South Carolina: Thomas Walter

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Specimen of Hydrangea arborescens subsp. radiata from the Walter Collection at the Natural History Museum, London Herbarium

In the last post, I described the work of Mark Catesby who traveled to the colonial South backed by patrons who were anxious for him to collect interesting plants, in part to adorn their English gardens.  This trend continued and a later visitor, John Fraser, arrived in Charleston after the American Revolution, in September 1786.  He was hunting for plants for British gardeners, most notably William Forsyth, Master of the King’s Garden in Kensington.  After meeting with the French botanist, André Michaux, who had a nursery near Charleston, Fraser headed north to visit the plantation of Thomas Walter.  An Englishman who settled in South Carolina around 1769, Walter eventually owned 4500 acres on the Santee River.  He occupied himself with business interests in Charleston and running his plantation, which in the South meant owning slaves.  In addition, he studied the botany of the region.  By the time Fraser visited, Walter had completed a flora of the Carolinas that included over 600 species.  Needless to say, he was a great help to Fraser in learning where to find interesting species.

Fraser traveled northwest to Augusta and spent the winter of 1786-87 collecting in northern South Carolina, some of the time accompanied by Michaux and his son.  While Fraser did not note localities for his collections, some are suggested by notes in Michaux’s journals.  In the fall of 1787 Fraser again visited Walter, who helped him identify his collections and write descriptions of new species, nearly 200 of them, that were added to Walter’s manuscript.  Fraser then packed up his 30,000 specimens as well as seeds and cuttings, and headed back to England in January 1788.  Walter entrusted his flora to Fraser, who arranged for its publication as Flora Caroliniana.  Because so many of the plants Fraser had collected were described by Walter and the specimens annotated by him, this collection became known as the Thomas Walter Herbarium.  But in a Taxon article entitled “The Thomas Walter Herbarium Is Not the Herbarium of Thomas Walter,” Daniel Ward (2007) makes it clear that this collection is of Fraser not Walter specimens.  Fraser saw Walter’s collection and received portions of specimens from him, but essentially the herbarium he brought to England was his own and is now at the Natural History Museum, London (NHM).

This provenance has some significance because many of the plants are type specimens for species first described by Walter, particularly for the ones that were collected by Fraser.  Ward’s article was written as he was preparing a book on Walter (2017) and involved in a project he called the “Walter Typification Project,” similar in its aims to the much larger Linnaeus Typification Project which spanned several decades and resulted in the publication of Order Out of Chaos (Jarvis, 2007).  Ward was very careful in his work.  Since the herbarium at NHM is not Walter’s, he assumes that these specimens weren’t used in writing species descriptions, so there are no holotypes in the collection.  However, where there is clear evidence that Walter saw and used Fraser’s material, then these are considered lectotypes.  For Walter names that do not have types, Ward chose recent collections as neotypes.

It is significant that Walter’s Flora Caroliniana was the first book on North American plants to use Linnaean nomenclature and to arrange species according to the Linnaean sexual system of classes.  It is obvious from the species descriptions in the Flora that Walter was well versed in Linnaeus’s work.  He owned copies not only of Species Plantarum, but also Systema Naturae and Genera Plantarum.  Ward thinks that the only plant that Walter included without having seen it, is the Venus flytrap, Dionaea muscipula, described by the British botanist John Ellis in 1768 from specimens sent him by John Bartram.

Walter died soon after the Flora was published at a relatively young 49 after being in ill health for some time.  One of his granddaughters became the mother of another prominent South Carolina botanist, Francis Peyre Porcher, who will be the subject of a future post.  William Fraser began a nursery business in England and specialized in North American plants.  He and his son traveled several times to the United States and also to Cuba and Russia.  They started a nursery in Charleston in 1791 and continued to ship plants from there back to England for 20 years.  It was Fraser’s son who gave his father’s herbarium to the Royal Horticultural Society, and when the Society got into financial trouble in the 1850s, the collection was sold to what was to become the NHM.

As with so much of the South’s past, there is little physical evidence of Walter’s life along the Santee.  Near his home, he had created one of the first botanical gardens in North America, shortly after those of John Bartram and his cousin Humphry Marshall in Pennsylvania.  This disappeared soon after his death, as eventually did his home and herbarium.  However, 25 years after his death two of his daughters had a marble slab, still extant, laid near the house site in his memory.  The dedication noted:  “To a mind liberally endowed by nature and refined by a liberal education he added taste for the study of Natural History and in the department of Botany, Science is much indebted to his labours” (Rembert, 1980, p. 12).

References

Jarvis, C. E. (2007). Order Out of Chaos: Linnaean Plant Names and Their Types. Linnaean Society.

Rembert, Jr, D. H. (1985). William Pitcairn, MD (!712-1791)—A biographical sketch. Archives of Natural History, 12(2), 219–229.

Ward, D. B. (2007). The Thomas Walter Herbarium is not the herbarium of Thomas Walter. Taxon, 56(3), 917–926.

Ward, D. B. (2017). Thomas Walter and His Plants: The Life and Works of a Pioneer American Botanist. New York Botanical Garden.

Botanists in South Carolina: Mark Catesby

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Plate 67 from the second volume of Catesby’s Natural History: Annona glabra

After a lifetime in New York, I moved to Aiken, South Carolina nearly three years ago, lured by family and a chance to retire into a different environment.  I’ve discovered a great deal in my time here, including the enchantments of shrimp and grits.  I’ve also tried to learn something of the botany of the state, thanks to my friends at the A.C. Moore Herbarium at the University of South Carolina (USC), Columbia, Herrick Brown, the curator, and John Nelson, the curator emeritus.  I’ve absorbed some botanical history and been lucky enough to have a small role in the new Mark Catesby Centre, part of the USC University Libraries.  This is a great time for the Centre to launch since 2022 marks the 300th anniversary of Catesby’s arrival in South Carolina on his second trip to North America, the one on which he did much of his observation, drawing, and specimen collecting for his two-volume The Natural History of Carolina, Florida and the Bahama Islands, a tour-de-force of science and art.

The Centre’s director, David Elliott, has had a long attachment to Catesby, having created the Catesby Trust, which has now morphed into the Centre.  Elliott led a week-long tour/conference on Catesby in 2012 and with Charles Nelson coedited The Curious Mister Catesby (2015), a book based on many of the presentations given that week.  I was on that trip and will never forget:  seeing the Smithsonian’s Catesby volumes in Washington, DC, listening to experts in Richmond discuss the background to Catesby’s work, attending a candle-light reception in Charleston, and seeing a host of waterfowl on a boat tour off Kiawah Island.  When I think of this amazing week, the images that come to mind are of Catesby’s etchings, the flora and fauna of the South Carolina coast, historical architecture, and amazing presentations.  The Curious Mister Catesby captures all these and helps to keep them fresh in my mind.  Catesby, of course, saw a very different South Carolina, though even then Charleston was a hub of commerce.  Plantations were already well established, sending rice, indigo, cotton, and tobacco to England and receiving manufactured goods and African slaves.  All this has permanently marked South Carolina and thanks to books like South Carolina: A History (Edgar, 1998), Down by the Riverside (Joyner, 1984), and In the Shadow of Slavery (Carney & Rosomoff, 2009), I am developing a better sense of the complexities of the South.

On his first to North America, Catesby sailed to Virginia in 1712, accompanying his sister who was married to a physician in Williamsburg.  He stayed for 7 years, meeting William Byrd II, who discussed natural history with him and allowed Catesby to use his library.  Catesby did some collecting and drawing, but not in a very organized way.  However, when he returned to England, he developed the idea of publishing a work on the natural history of this fascinating new world.  He seems to have known enough and displayed enough evidence that he convinced the avid natural history collectors of London of his plan’s viability.  Coming from a well-educated but not very affluent British family, he definitely moved in impressive circles.  He knew the great collector Hans Sloane (see earlier post) who amassed the most impressive herbarium of his time (Delbourgo, 2017), as well as James Petiver, perhaps the most zealous collector in the sense of having a worldwide network of ships captains, colonists, merchants, and clergymen gathering specimens (Stearns, 1952).  In terms of assisting Catesby financially and botanically, there was William Sherard at Oxford, who identified many plants for Catesby.

On his second trip to America, Catesby landed in Charleston and traveled through what is known as the low country, along the coasts of North and South Carolina.  He journeyed up the Savannah River, which marks much of the border between South Carolina and Georgia, as far inland as what is now Augusta, which I might add in only a half hour from Aiken.  This was territory with a few colonial outposts and where Catesby and his companions would have encountered indigenous peoples, pine forests, and rolling hills.  This is now my country and I enjoy having some small tie with Catesby, and also with Pennsylvania nurserymen John Bartram and his son William who also visited this area forty years later, followed still later by the French botanist André Michaux.  Catesby eventually visited coastal areas of Florida and then spent almost a year in the Bahama Islands, explaining why there are so many tropical plants, fish, and birds in the Natural History.

In 1726, Catesby returned to England and worked for nearly 20 years producing his magnus opus.  He found it too costly to have his watercolors engraved, so he learned the process, producing what are considered by many to be masterpieces.  He even oversaw the coloring of the engravings in the first edition.  He worked as a nurseryman to provide needed income and as a way to observe some of the species he had first seen in the colonies.  He also received specimens and seeds from John Bartram, sending him and also Carl Linnaeus copies of his books.  This is how a number of his engravings have become lectotypes for 14 species named by Linnaeus (Jarvis, 2015).  There are Catesby specimens today in the Hans Sloane collection at the Natural History Museum, London, and at the Oxford University Herbarium, the home of Sherard’s specimens.  I am happy to note that the USC Libraries have the first and second editions of both Volumes I and II of the Natural History, as well as a copy of Hortus Europae Americanus, containing descriptions of 85 North American trees and shrubs, that Catesby had been working on when he died and was published posthumously.

References

Carney, J. A., & Rosomoff, R. N. (2009). In the Shadow of Slavery: Africa’s Botanical Legacy in the Atlantic World. University of California Press.

Delbourgo, J. (2017). Collecting the World: The Life and Curiosity of Hans Sloane. Harvard University Press.

Edgar, W. (1998). South Carolina: A History. University of South Carolina Press.

Jarvis, C. E. (2015). Carl Linnaeus and the influence of Mark Catesby’s botanical work. In E. C. Nelson & D. J. Elliott (Eds.), The Curious Mister Catesby (pp. 189–204). University of Georgia Press.

Joyner, C. (1984). Down by the Riverside: A South Carolina Slave Community. University of Illinois Press.

Nelson, E. C., & Elliott, D. J. (Eds.). (2015). The Curious Mister Catesby: A Truly Ingenious Naturalist Explores New Worlds. University of Georgia Press.

Stearns, R. P. (1952). James Petiver: Promoter of natural science, c. 1663-1718. Proceedings of the American Antiquarian Society, 62, 243–365.

Note: I am very grateful to David J. Elliott, director of the Mark Catesby Centre in the University Libraries of University of South Carolina, Columbia for inviting me to participate in the Centre’s work.

Getting the Most Out of Herbaria: In So Many Ways

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Images from Tweet sent by the Georgia Southern University Herbarium

So far in this series of posts on the uses of herbarium specimens in research (1,2,3), I’ve stuck to those that are most commonly discussed:  taxonomic and floristic work, environmental change studies, and phylogenetics.  But there are many other uses, with the variety increasing because digitization makes specimen information more easily available to a broader audience.  There have been studies on the presence of plant pathogens in specimens, including fungal infections (Kido and Hood, 2019).  Anther smut was found detected on specimens through visual inspection under a microscope (Antonovics et al., 2003).  Recently, sensitive DNA sequencing techniques have made it possible to detect bacterial infections by differentiating between pathogen and host DNA.  There is even Defense Department interest in such research.  The Center for the Study of Weapons of Mass Destruction in Washington DC issued a report where they outline why natural history collections can be sources of information in the work of protecting against biological warfare.

Different groups of researchers look at herbarium specimens very differently.  Those investigating fungi might focus on the roots, such as in a study about the successful extraction of arbuscular mycorrhizal fungal DNA from vascular plant roots.  Other botanists have developed techniques for systematically evaluating the amount of herbivore damage to leaves by using a grid system (Meineke & Davies, 2019).  While it’s common to find dead insects on a specimen, snails hiding out are more of a surprise.  Researchers examining lichens and bryophytes from the Galapagos Islands found that 10% of 400 specimens had at least one of eight different micro-mollusk species adhering to them.  There was even a new species discovered.  It is not unusual for new plant species to be found among herbarium specimens (Bebber, 2010), but snails are another thing.

Specimens can also be useful before trips to collect more specimens; Kew Botanic Gardens has a handbook with specimen images as a guide for collectors.  Searching databases for where a particularly narrowly endemic species was found in the past increases a botanist’s chances of finding it again.  One approach is searching for associated species in locality information.  Botanists are being encouraged to list such data to make specimens more valuable in ecological studies.  Another way to enhance specimens is to link them to other types of data such as iNaturalist observations from the same locale.  Heberling and Isaac (2019) describe how they are doing this at the Carnegie Museum of Natural History’s herbarium in Pittsburgh.  The iNaturalist data can include photos taken on the site by citizen scientists.  These visual records may document traits such as flower color and form that are difficult to preserve in dried specimens.   There may also be information about the surrounding habitat.  Having these items linked to specimens is a step toward the development of what is termed the Extended Specimen Network, with the specimen is at the center of linked resources providing information on the genetics, ecology, and morphology of the species (see earlier post).

Besides scientific uses, herbaria can also have what could be termed sociological uses.  There are several ways in which digitization of natural history collections could lead to more diversity among researchers.  Online access means that those interested in taxonomy who are living in developing nations can more easily access not only specimen data but related research through such portals as GBIF.  This also makes it easier for them to find research partners in developed nations.  A very different approach to expanding diversity has been employed by several institutions in the United States:  enlisting those in juvenile detention centers and those recently released from such facilities in digitizing specimens.  These projects not only provide employment, but also broaden the participants’ experience of science and of working with databases.  It is a nice example of thinking more creatively about expanding the population of those interested in nature and opening up herbaria in novel ways.  The iDigBio project held a webinar on this topic to make the natural history collection community aware of this approach, document the progress that has already been made, and encourage other ways to think outside the box in drawing people to natural history.

I haven’t mentioned using herbarium collections in outreach programs because I covered this in a recent post.  However, I have recently come across a few examples that seem too good to ignore.  The first is a “Hookathon: Hacking the Herbarium” at the Royal Botanic Gardens, Kew.  This was an all-day citizen science event to digitize items in Kew’s massive collection of material related to Joseph Dalton Hooker, who led the garden for many years during the second half of the 19th century.  This was also a means to advertise the collection’s existence and its variety, including specimens, manuscripts, letters, and drawings.  At the University of Manchester in Britain, the herbarium opened its doors to students during the exam period for “well-being” events so they could unwind by drawing specimens and incidentally find out what a herbarium is about.   I would like to end with a political, yes a political, example of outreach.  A Tweet from the Georgia Southern University Herbarium reminded residents about voting and put in a plug for the state symbol, the peach, with a beautiful fertile specimen.  This is outreach at its most creative.

References

Antonovics, J., Hood, M. E., Thrall, P. H., Abrams, J. Y., & Duthie, G. M. (2003). Herbarium studies on the distribution of anther-smut fungus (Microbotryum violaceum) and Silene species (Caryophyllaceae) in the Eastern United States. American Journal of Botany, 90(10), 1522–1531.

Bebber, D. P., Carine, M. A., Wood, J. R. I., Wortley, A. H., Harris, D. J., Prance, G. T., Davidse, G., Page, J., Pennington, T. D., Robson, N. K. B., & Scotland, R. W. (2010). Herbaria are a major frontier for species discovery. Proceedings of the National Academy of Sciences, 107(51), 22169–22171.

Heberling, J. M., & Isaac, B. L. (2018). iNaturalist as a tool to expand the research value of museum specimens. Applications in Plant Sciences, 6(11).

Kido, A., & Hood, M. E. (2020). Mining new sources of natural history observations for disease interactions. American Journal of Botany, 107(1), 3–11.

Meineke, E. K., & Davies, T. J. (2019). Museum specimens provide novel insights into changing plant–herbivore interactions. Phil. Trans. R. Soc. B, 374(1763), 1-14.

Getting the Most Out of Herbaria: The Environment

A major argument used for preserving and digitizing natural history collections is that they contain critical information useful for researchers attempting to understand climate change.  This idea is now so much a part of the herbarium communities’ thinking that I hesitate to mention it, but there are some interesting examples worth noting on how botanists are mining collections.  Phenological research on specimens have been going on for years and its success in documenting changes in flowering, fruiting, and other points in plant life cycles have bred more such work.  This has gotten to the point where digitization efforts have become more focused on carefully documenting the phenological status of plants in a rigorous and systematic way, so this information can be mined from databases.  The NSF is sponsoring a project of the California Herbarium Consortium to do just this, including training citizen scientists to identify phenological status and record it in the online specimen records (Yost et al., 2020).

However, there isn’t a clear cause and effect relationship between increasing temperature and phenology.  Some species seem more affected than others, and some show little effect, with many factors involved in these differences.  Also, phenological changes can lead to more than just a habitat too warm for a particular species.  For certain orchid species, flowering times have not changed, but the emergence their pollinators have been pushed earlier.  This means that the pollinators will not find the resources they need from these orchids, and when the flowers do bloom, the insects they rely on may no longer be around or may have moved on to other species.  It’s a complicated dynamic, which is why a variety of species in many different habitats need to be investigated.

One cause of climate change—carbon dioxide (CO2) increases in the atmosphere—can have effects on plant physiology and morphology.  Not surprisingly these include an impact on the apparatus for the process that uses the gas, namely photosynthesis.  Researchers in New Zealand measured stomatal density on leaves in specimens from their national herbarium.  Since stomata are the leaf structures that allow in CO2, their number indicates how much of the gas a leaf can absorb at one time.  Some material in the study dated back to Captain James Cook’s first voyage to New Zealand in 1769-1790.  Since the specimens were so old and fragile, the botanists employed an indirect technique to examine the leaves.  After painting the leaves with gel that was allowed to harden, they gently removed the film, which had an impression of the stomata from the leaf surface.  Karaka tree leaves (Corynocarpus laevigatus) gave particularly good prints.  Fortunately, specimens of this species had been collected at several sites.  The researchers also counted stomata on Karaka leaves collected in the late 19th century, as well as modern specimens and fresh material.  There was little difference in stomata density between the 18th and 19th century, but the modern-day leaves had about 50% fewer pores, suggesting that increased CO2 concentrations in the air meant that the plant could absorb the same amount of gas while expending less energy creating these structures.  I went into this example in some detail to show the thinking and work involved in any one study to provide a single piece of information about the climate change puzzle.

While fungi are not technically plants, historically they have been treated as such, remain in many herbarium collections, and are studied by those who call themselves botanists.  Researchers at the University of Arizona have created a collection of 7,000 specimens of endophytic and endolichenic fungi, that is, those that live inside the cells of healthy plants and lichens respectively.  This team emphasizes that they are dealing with healthy organisms, since the fungi are beneficial rather than harmful to their hosts.  These fungi are receiving a great deal of attention because of their importance in moving nutrients between plants and the environment.  What makes this particular collection significant is that it is not historical.  It was created in the digital age, with all the information entered directly into a database with extensive metadata on location and host, as well as genetic sequencing data, namely DNA barcodes.  The latter provide a way to identify many fungi that are otherwise difficult to distinguish from one another.  The organisms were collected from a variety of plant and lichen hosts at 50 locations throughout Arizona, representing a range of habitats.   Because the resulting database is so sophisticated, researchers were able to analyze the data and “highlight the relevance of biogeography, climate, hosts, and geographic separation in endophyte community composition” (Huang et al., 2018, p. 47).

Another Arizona study was done by a student at Arizona State University who collected weedy plants from alleyways in Tempe, Arizona.  He used the SEINet database of southwestern plant specimens to attempt tracking the first occurrence of these weeds in the area.  He collected specimens from 83 species, but was only able to trace a portion of these back to early introduction.  However, the study serves as a baseline for future work on urban weeds, a topic gaining more attention.  A small but useful study done in Mexico showed that the measure of weediness among a group of related species was about the same when based on field observations versus herbarium specimens.  They employed a recognized scale of synanthropy, that is, the “degree to which a species associates with human-caused disturbance” (Hanan-A et al., 2016, p. 1).  They found that the index generated comparable weediness ratios from field observations and herbarium specimens, indicating that specimens could be used to measure weediness.

References

Hanan-A., A. M., Vibrans, H., Cacho, N. I., Villaseñor, J. L., Ortiz, E., & Gómez-G., V. A. (2016). Use of herbarium data to evaluate weediness in five congeners. Annals of Botany Plants, 8.

Huang, Y.-L., Bowman, E. A., Massimo, N. C., Garber, N. P., U’Ren, J. M., Sandberg, D. C., & Arnold, A. E. (2018). Using collections data to infer biogeographic, environmental, and host structure in communities of endophytic fungi. Mycologia, 110(1), 47–62.

Yost, J. M.et al. (2020). The California Phenological Collections Network: Using digital images to investigate phenological change in a biodiversity hotspot. Madroño, 66(4), 130–141.