From Plant Press, Vol. 27, No. 3, July 2024.
By Gary A. Krupnick
The Smithsonian’s National Museum of Natural History (NMNH) Department of Botany, the United States Botanic Garden (USBG), and the Smithsonian Gardens held the 21st Smithsonian Botanical Symposium, “Advancing Plant Conservation Through Horticulture,” on May 17, 2024. The hybrid event brought together five engaging speakers who presented their research to both an in-person and a virtual audience from around the world. Scientists and horticulturalists from botanic gardens and conservation organizations spoke about how they maintain diverse and wild-collected ex situ plant collections, care for plants of concern in situ, provide plants for population augmentation and repopulation, and support conservation education and advocacy.
Eric Schuettpelz, NMNH Curator of Botany, welcomed the audience to the symposium. Rebecca Johnson, the CW Whitney Chief Scientist and Associate Director for Science at NMNH, highlighted the mission of the Smithsonian as well as the immense collections housed in the museum and especially the U.S. National Herbarium. She particularly gave praise to the work of digitizing all pressed specimens in the herbarium and the many benefits of having that data online. Susan Pell, USBG Executive Director, also provided opening remarks and gave an orientation to the USBG, including its history, a description of the living collections, their scientific research, and their scientific and conservation partnerships.
Rebecca Johnson, Associate Director for Science at NMNH (left), and Susan Pell, USBG Deputy Executive Director (right), deliver opening remarks welcoming everyone to the National Museum of Natural History. (photos by Ken Wurdack)
Laurence Dorr, NMNH Curator of Botany, presented the José Cuatrecasas Medal for Excellence in Tropical Botany to Peter F. Stevens, an accomplished professor of biology at the University of Missouri, St. Louis, and a prominent research curator at the Missouri Botanical Garden. In addition to the typical biographical sketch, Dorr reminisced about the mentorship he received from Stevens in the 1970s. Accepting the award, Stevens remarked about how little we really know about the big picture in many aspects of tropical botany, including tropical trees in Ericales and Malpighiales. He said that to really understand evolution, there is more to learn about species relationships as well as basic morphology and anatomy.
The first presentation of the symposium was delivered by Carlos Magdalena from the Royal Botanic Gardens Kew. He opened his talk, “The many facets of botanical horticulture,” with a broad description of how botanic gardens, specifically Kew Garden, have a mission to educate, provide public enjoyment, and to celebrate heritage. Focusing on botanical horticulture, Magdalena spoke about his work on the café marron, Ramosmania rodriguesi, a tree native to the Mauritian island of Rodrigues in the Indian Ocean. Once declared extinct, an individual plant was later discovered by a schoolboy, and several cuttings were made. After 20 years of trying to get the plants to produce seed, Magdalena was finally successful in getting the plant to fruit. More interesting was the fact that the plant takes on two forms, where younger plants look very different than mature plants. Having the plants growing in the greenhouse allows scientists to learn more about their natural history and can provide clues for conservation horticulture, which resulted in the ability to plant hundreds of seeds back into the wild. Magdalena is conducting similar research on Elaeocarpus bojeri, Chassalia boryana, and Roussoea simplex, the latter being pollinated by gecko lizards, one of the only plants that has the same pollinator as its seed disperser. He also spoke about the importance of training local communities on how to propagate important economic plants, and gave an example of the Brazil nut, Bertholletia excelsa, in Bolivia.
The second half of Magdalena’s presentation was on water lilies and his adventures in Australia and Bolivia. In Australia he collected species like Nymphaea alexia, N. kimberleyensis, and N. lukei. He spoke about the extremely rare N. thermarum, which at one point was stolen from Kew Gardens. The publicity of that incident brought much attention to Magdalena and the importance of the conservation of water lilies. He then wrote a book, The Plant Messiah, which allowed him to further convey messages about plant endangerment. In Bolivia, he studied the closely related Victoria amazonica, V. cruziana, and the largest water lily in the world, V. boliviana. Displaying these related species at Kew has given him an avenue to explain the importance of taxonomy, botanical illustration, molecular work, and phylogenetics of flowering plants.
The second speaker of the day was Jennifer Cruse-Sanders from the State Botanical Garden of Georgia, who gave the presentation, “From dwarf sumac, Rhus michauxii, to turkey beard, Xerophyllum asphodeloides (and other species in between): How conservation horticulture has helped to preserve imperiled species in the southeastern U.S.” She asked the main question, “How can we translate what we know about how plants grow to better conserve them?” Grand challenges she highlighted include the loss of plant diversity, the loss of ecological connections, and the loss of connections between people and plants. One of the ways that botanists can address some of these challenges is through partnerships, and Cruse-Sanders pointed out that for nearly 30 years the State Botanical Garden has coordinated the Georgia Plant Conservation Alliance. Priority actions we can take include conservation horticulture, applying technological and scientific advancements to help us understand how to propagate rare species, safeguarding populations, and developing a native seed network for restoration.
Cruse-Sanders used three case studies to make her point. Rhus michauxii, one of the rarest shrubs in North America, is dioicous with an all-male population separated 160 km from an all-female population. She described propagating individuals in the greenhouse, applying fire to the wild locality, and introducing stems into the wild, all to encourage pollination—what she called a “botanical dating service.” After the pollination trials, she initiated seed germination trials and learned lessons on how best to germinate this species. The second case study was Xerophyllum asphodeloides, a rare species in which seed propagation studies were needed. After experimenting in scarification, stratification, and soil mixtures, her team successfully germinated, grew, and planted this species back into the wild. In the final case study, she tested the levels of genetic diversity to determine why some plants, such Pityopsis ruthii, are rare and others, such as P. graminifolia, are more common. Unsurprisingly, she found that a majority of the genetic diversity is held within the more common species. A phenotypic plasticity project, however, found that plasticity could be facilitating habitat specialization but constraining distribution. These findings could help explain the specific habitat restrictions of P. ruthii.
Colin Khoury from the San Diego Botanic Garden spoke about, “Distributions, conservation assessments, and conservation action for crop wild relatives.” Khoury focused his talk on describing the wild relatives of the foods we eat, how well they're conserved, how to conserve them in seed banks, and how to breed them to make our agriculture more resilient to climate change. He first described a study of a wild grape, Vitis monticola, and other taxa, conducting gap analyses to determine how well they have been collected and where one might go to collect possibly novel genes for each species. He then spoke about an inventory of U.S. crops, and described the 2,598 crop wild relatives and the 2,148 native crop wild relatives in the U.S. The highest richness are wild relatives of sunflowers, blackberries, blueberries, grapes, peaches, pecans, plums, and gooseberries. In describing the conservation status of wild relatives, Khoury says that much work is still to be done in collecting these species, putting them into our botanic gardens and seed banks, and protecting them in open spaces.
Khoury pointed out five important tenants: the need to understand where the species live and how well they are protected; the need to protect them in their natural habitats; the need to collect and preserve them in botanic gardens and seed banks; the need to conduct breeding science to make them usable in agriculture; and the need to raise public awareness. He wrapped up his talk by speaking about current efforts to conserve wild relative species, including a citizen science project in iNaturalist to understand where wild relatives grow, and the efforts of the North American Fruit and Nut Tree crop wild relative working group.
Dustin Wolkis from the National Tropical Botanical Garden in Hawaii spoke next about, “Applied seed conservation biology to support seed banking.” Wolkis began with an overview of Hawaii and its diverse and threatened flora, and then jumped into the four major challenges of seed conservation: few seeds, storage behavior, longevity, and germination. For storage behavior, Wolkis described water balance in seeds and the need for desiccation in orthodox seed banking. For longevity, he described seed survival curves and the need to test viability to assess longevity and to calculate the recollection interval necessary to refresh the seedbank. In a test on seed longevity on herbarium sheets, he described how not a single seed germinated from the pressed specimens of ohi’a, Metrosideros, or from the sheets of several other target species of endangered species. Wolkis described how the Hawaiian flora has the highest proportion of freeze sensitive storage behavior than any other flora. He also spoke about conducting seed lipid thermal fingerprint studies and found very distinct signatures across species that could be related to this freeze sensitivity. Lipid thermal fingerprints offer a rapid, non-destructive test to screen for potential problems with longevity, and they could be generated for all seed bank accessions.
In describing dormancy and germination, Wolkis said that seeds need optimal germination conditions and an external signal to get robust germination. While experiments have been performed on individual species, he thinks it's time to take a holistic look at dormancy and germination in the entire Hawaiian flora and look for larger patterns. He spoke about rapid ohi'a death and a study that found that there were no correlations with initial viability and any bioclimatic variable, but there was a correlation with seed zones. Wolkis briefly spoke about fern spore banks and pollen banks as well. He gave case studies of developing protocols for pollen conservation for Hibiscus clayi and Pritchardia minor. He thinks that pollen storage is the next critical tool in the plant conservation toolkit.
The final invited speaker of the day was Abby Meyer from Botanic Gardens Conservation International (BGCI), who spoke on “Conservation horticulture capacity at botanic gardens.” She described the global botanic garden community as ~3,500 institutions that collectively maintain at least 30% of known plant diversity, at least 40% of known threatened species, employing collectively ~60,000 technical experts who know how to grow and document the plants of most terrestrial ecosystems on Earth, and collectively engage 1 billion visitors every year, making this community the world's greatest force for plant conservation. She spoke about the various unique roles that botanic gardens fill, including plant science, horticulture and breeding, ex situ collections, in situ collections, and outreach and education, and she expanded in detail upon each role. Meyer described a case study of sand blasting seedlings of Penstemon havdenii, a species native to the sand hills of Nebraska, as an example of how each species has a code to crack that allows one to successfully grow it across its conservation path.
Meyer spoke about a global survey that was recently conducted by BGCI. The survey characterized the current work being done and the perceptions of conservation horticulture by those who work at botanic gardens. One key finding is that after taking the survey, most respondents said that their view either has not changed as they were already engaged in conservation horticulture or that they realized that they are more engaged in conservation than they previously thought. The most reported needs from the respondents included funding, mentorship, information (propagation protocols), and training (seed conservation and genetics). Additional interviews provided a deeper dive into entry points into the career of conservation horticulture and valuable learning experiences. The main findings of the surveys were that awareness and perspective seem to be critical factors in conservation horticulture, the most effective tools are hands on training in the field, nursery, and lab, and institutional value and priority by garden leadership is important. Meyer finished by talking about a new propagation exchange tool that connects repositories of data among botanic gardens and about the Keller Scholarship in Conservation Horticulture which is offered annually to undergraduates who are hosted at botanic gardens in the U.S.
The final session of the Symposium was a panel discussion with the five speakers and moderator Susan Pell (USBG). Questions from the in-person and virtual audiences and the moderator included: how should we better unite the fields of conservation and horticulture?; how should we balance the connection of displaying charismatic plant species and having the resources to conserve the endangered ones?; what current trends exist for students, volunteers, citizen scientists, and lifelong teachers?; how can we better utilize commercial growers for plant conservation?; and what is the best approach for homeowners to support endangered native plant species? To hear the fascinating responses to these questions by each of the speakers, a video of the panel discussion is available on YouTube.
The Symposium concluded with evening events at the U.S. Botanic Garden’s Conservatory, including a closing reception and a poster session.
Peter Stevens (right), the recipient of the 21st José Cuatrecasas Medal for Excellence in Tropical Botany, and attendee Laura Lagomarsino (Louisiana State University) look at floral displays during the closing reception at the US Botanic Garden.
Graduate student Emily Poindexter presents her research during the closing reception and poster session at the US Botanic Garden.
(photos by Ken Wurdack)
Smithsonian Gardens and Smithsonian Libraries and Archives provided optional behind-the-scenes tours the morning of the Symposium. Both units offered two sessions each and all were well attended.
Staff from the Smithsonian Gardens led a tour around the NMNH grounds highlighting the gems of the gardens surrounding the building. Arborist Jake Hendee discussed the significance of local trees and the importance of evaluating their health. Sylvia Schmeichel, lead horticulturist, highlighted the design of the pollinator garden and the value of trying new species, like the Loblolly Bay tree recently added. Horticulturist Phil Evich walked the groups through different sections of plants on the Mall side of NMNH emphasizing the value of experimental gardens using different textures, colors, and sizes to keep the collections interesting. As educators and garden curators, they all explained that the gardens are a living museum, always changing, and always accessible. They also spoke about how the living collections are a way to support conservation efforts in the garden and to support local ecology.
Left: Phil Evich singing praises to the plant textures and sizes keeping the gardens interesting.
Right: Sylvia Schmeichel highlighting newcomers to the pollinator garden.
(images by Rose Gulledge)
The Smithsonian Libraries and Archives hosted a tour of the Joseph F. Cullman 3rd Library of Natural History. Leslie Overstreet, Curator of Natural History Rare Books, and Sydney Fitzgibbon, Library Technician, provided background information about the selected botanical books on display. Overstreet also talked about the uniqueness of the library and the services offered. Participants were able to peruse the books up close to view the detailed illustrations about early herbals, travels, taxonomy, and trees. There was even a book detailing the theory and practice of planting forest trees, William Pontey’s The Profitable Planter (1808). Then a bonus: attendees were given a view into the temperature and humidity-controlled vault housed within the Cullman library to view Jonathan Singer’s Botanica Magnifica (2009), a lavishly bound massive double elephant folio volume of 250 photographs of exotic and rare flowers and plants.
Left image: Sydney Fitzgibbon (far left) assists Leslie Overstreet (right) with Jonathan Singer’s Botanica Magnifica (2009).
Right image: Early herbals: Hieronymus Bock’s Kreütterbuch (1587).
(photos by Rose Gulledge)
The symposium attracted an audience of about 400 attendees, with about 150 people in-person and 250 people online. Those who viewed the proceedings virtually watched from 22 countries from around the world. All speaker presentations, opening remarks, the presentation of the José Cuatrecasas Medal, and the roundtable panel discussions were recorded and are available for viewing on NMNH’s Natural History for Scientists YouTube page.
The 22nd Smithsonian Botanical Symposium is tentatively scheduled to take place at the National Museum of Natural History and the U.S. Botanic Garden on Friday, May 16, 2025. The topic is still to be determined. Check the Department of Botany’s website for updates.
Video playlist of the 21st Smithsonian Botanical Symposium:
Do you have a video of the presentations?
Posted by: Susan | 08/23/2024 at 06:15 PM
All of the videos are here: https://www.youtube.com/watch?v=hs1GRzYN9hA&list=PLQmxS2U3B6Kbo8GKodMg6FB6K5EHaBaVI&index=28
Posted by: Gary | 08/26/2024 at 09:28 PM