# S.59 BIOGEOGRAPHIC HISTORY AND ECOLOGICAL PROCESSES OF THE ASIA-AUSTRALASIA FLORISTIC EXCHANGE

## S.59.1 Documentation of flora in the Kimberley Gateway to facilitate studies of Sunda – Sahul exchange

Russell L. Barrett¹,², Matthew D. Barrett³, Francis Nge¹, Limin Lu⁴,⁵, Russell L. Barrett¹,², Matthew D. Barrett³, Francis Nge¹ and Limin Lu⁴,⁵

1 National Herbarium of New South Wales, Botanic Gardens of Sydney, Australian Botanic Garden, Locked Bag 6002, Mount Annan, New South Wales, Australia. 2 Evolution and Ecology Research Centre, School of Biological, Earth, and Environmental Sciences, University of New South Wales Sydney, Kensington, NSW, Australia. 3 Australian Tropical Herbarium, James Cook University, PO Box 6811, Cairns, Queensland, Australia. 4 State Key Laboratory of Plant Diversity and Specialty Crops, Institute of Botany, Chinese Academy of Sciences, Beijing, China. 5 China National Botanical Garden, Beijing, China

Biodiversity knowledge of north-western Australia's Kimberley region remains low. However, there is a growing body of evidence to suggest that the region has acted as an important gateway for the transfer of biodiversity between Sunda and Sahul due to its proximity to the Indonesian archipelago. We present data based on thirty years of field- and herbarium-based biodiversity discovery demonstrating changes in our understanding of plant diversity in the Kimberley, supporting its regional significance. Covering 100,000 km² in the Australian tropical savanna bioregion, the Kimberley is home to nearly 3,400 angiosperm taxa, of which 40% have only been recognised in the last 30 years. Endemism had been assumed to be low (<10%), but new species records have mostly been localised, and endemism is now >22%. Biogeographic connections are very varied, but include SW, Central, SE and tropical Australia, many parts of SE Asia west to India, and also Madagascar. We present example phylogenies that demonstrate the relevance of the Kimberley region for biogeographic analyses, demonstrating that some groups have followed multiple tracks into and from Australia. We summarise additional groups

that would benefit from inclusion in future phylogenetic studies for the purpose of biogeographic reconstructions. Potential mechanisms of dispersal will be discussed.

## S.59.2 Exploring the timing and mode of evolution of Asian and Australasian biogeographic exchanges in a framework of global biogeography

Jun Wen¹, Alicia Talavera¹, Zhiyao Ma², Limin Lu³, Richard Hodel¹, Liang Zhao⁴, Gabriel Johnson¹, Virginia Valcárcel⁵, Russell Barrett⁶, Elizabeth Zimmer¹, Zelong Nie⁷

1 Department of Botany, Smithsonian Institution, Washington, USA. 2 Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China. 3 Institute of Botany, Chinese Academy of Sciences, Beijing, China. 4 College of Life Sciences, Northwest A&F University, Yangling, China. 5 Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain. 6 National Herbarium of New South Wales, Mount Annan, Australia. 7 College of Biology and Environmental Sciences, Jishou University, Jishou, Hunan, China.

The Asian – Australasian regions harbor rich biodiversity and represent an ideal natural laboratory to explore biogeographic exchanges and pathways, tropical – temperate biome transitions, and plant diversification in response to tectonic movements and climate changes. In this study, we analyze the biogeographic exchanges between Asia and Australasia in a global context in Araliaceae, Calycanthaceae, the Gymnostachydoideae-Orontioideae clade of Araceae, the Leeaceae/Vitaceae clade, *Prunus* of Rosaceae, *Toxicodendron* and its close relatives of Anacardiaceae, and the conifer family Taxaceae. Our analyses reveal extensive biogeographic exchange among major Gondwanan
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landmasses in the Cretaceous and early Paleogene. Antarctica, Africa, India, and South America played an important role in the biotic exchange of disjunct plants between Asia and Australasia in the early phase, with the existence of the Antarctic land bridge linking Australia, Antarctica and South America, and the Kerguelen Plateau land bridge connecting Antarctica and India. Hence the Asian and Australasian biotic exchanges in the Cretaceous and early Paleogene were mostly via indirect migration and dispersal. Subtropical East Asia and the adjacent tropical southeast Asia developed a rich forest flora that was highly influenced by the East Asian monsoon, the Indian monsoon, and the uplift of the Qinghai-Tibetan plateau. During the Neogene, biogeographic exchange between the Sunda and Sahul regions became highly active after the collision of the Australian continental crust with southeast Asia, with a more dominant Sunda-to-Sahul dispersal pattern. Continental Asia, including tropical Southeast Asia to subtropical East Asia, was a dominant source area for the later Miocene/Pliocene phase of the Asian - Australasian biotic exchanges. Our results also support dispersals from continental Asia to New Guinea, independent dispersals from continental Asia to Sunda and Sahul in a given lineage, and a recent biogeographic corridor linking Taiwan, the Philippines and New Guinea in the late Neogene via long distance dispersal.

**S.59.3 Asymmetric migration dynamics of the tropical Asian and Australasian floras**

Li-Guo Zhang¹, Xiao-Qian Li², Wei-Tao Jin¹, Yu-Juan Liu¹, Yao Zhao¹, Jun Rong¹, Xiao-Guo Xiang¹

1 School of Life Sciences, Nanchang University, Nanchang, China. 2 Institute of Botany, Chinese Academy of Sciences, Beijing, China

The tropical Asian and Australasian floras have a close relationship, and is a vital distribution pattern of seed plants worldwide. As estimated, more than 81 families and 225 genera of seed plants distributed between tropical Asia and Australasia. However, the evolutionary dynamics of two floras were still vague. Here, a total of 29 plant lineages, represented the main clades of seed plants and different habits, were selected to investigate the biotic interchange between tropical Asia and Australasia by integrat-

ed dated phylogenies, biogeography, and ancestral state reconstructions. Our statistics indicated that 68 migrations have occurred between tropical Asia and Australasia since the middle Eocene except terminal migrations, and the migration events from tropical Asia to Australasia is more than 2 times of the reverse. Only 12 migrations occurred before 15 Ma, whereas the remaining 56 migrations occurred after 15 Mya. The MDE (maximal number of potential dispersal events) analysis also show obviously asymmetry with southward migration as the main feature, and indicated the climax of two direction migrations occurred after 15 Mya. We speculated that the formation of island chains after the Australian-Sundaland collision and climate changes have been beneficial for seed plants migrations since the mid-Miocene. Furthermore, biotical dispersal and stable habitat may be crucial for floristic interchange among tropical Asia and Australasia. Thus, this study provides evidence for the past floristic exchanges between tropical Asia and Australasia.

**S.59.4 Biogeographic history and ecological processes of the Asia-Australasia floristic exchange: history, progress and prospect**

Zhi-Duan Chen¹, Dan-Xiao Peng¹, Hai-Hua Hu¹, Li-Min Lu¹, Russell Barrett², Jun Wen³

1 Institute of Botany, Chinese Academy of Sciences, Beijing, China. 2 National Herbarium of New South Wales, Australian Botanic Garden, Australia. 3 Department of Botany, Smithsonian Institution, Washington, USA

The Asia-Australasia floristic exchanges have long attracted the attention from evolutionary biologists with its complex geologic background and remarkable associated biodiversity. The rich floras of Asia and Australasia converge at the unique Wallacea transition zone, which is noted for the well-known Wallace's Line and its outstanding tropical biodiversity. Since the early 19th century, critical insights have been proposed concerning the extent, timing, and routes of the Asia-Australasia floristic exchange, as well as characteristics of the exchanged elements and ecological filters of the exchange processes. We present the early exchanges dated to the supercontinent, the recent affinities during the Quaternary glacial fluctuation, and even the invasive biotic dynamics in the Anthropocene. By
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integrating distribution data and evolutionary information of plant lineages within the Asia-Australasia convergent region, southwestern Asia showed the highest plant richness, while southern Asia to eastern Australia showed the highest the phylogenetic diversity, indicating that the flora of southern Asia to eastern Australia has together preserved ancient and diverse evolutionary history with frequent interchanges within the region. To better reflect the relationships among floras inside the region, we revisited the regionalization inside the region under a robust phylogenetic framework of the global seed plants and delineated the three phytogeographic areas: the Asia continent and Sunda region, the Wallacea region, and the Sahul region. We found the dispersal exchange among these three areas dominated in a time period after the middle Miocene, consistent to the time when northern and southern shelves in Southeast Asia collided and the migration showed significant asymmetry with the southward dispersal exceeding the northward dispersal. We expect the understanding of the evolutionary history of Asia-Australia flora would shed light on the development history of global biodiversity distribution pattern and provide the theory foundation for biodiversity conservation in addition to new understanding in the biogeography.

**S.59.5 Crossing Wallacea: floristic exchange between East Asia and Australasia**

Dan-Xiao Peng¹, Li-Min Lu¹, Andrew H. Thornhill²,³, Brent D. Mishler⁴, Bing Liu¹, An-Ming Lu¹, Joseph T. Miller⁵, Zhi-Duan Chen¹

1 Institute of Botany, Chinese Academy of Sciences, Beijing, China. 2 State Herbarium of South Australia, Adelaide, South Australia, Australia. 3 The University of Adelaide, Adelaide, South Australia, Australia. 4 University of California, Berkeley, California, USA. 5 Global Biodiversity Information Facility, Copenhagen, Denmark

One of the best cases for investigating the history of biotic exchange is the convergence of the Sunda (the southeastern extension of the continental plate of Asia) and Sahul (the tectonic plate of the Australian continent) shelves, where the remarkably diverse Wallacean region is located. Located on either side of the Sunda-Sahul zone, the floras of East Asia and Australasia harbor flourishing, distinctive, and comparable plant diversity and shared a considerable number of taxa, which provide an ideal example to test the effects of geological history and ecological conditions on exchange dynamics, to what extent plants could spread over Wallacea, and the contributions of exchange to floral formation. We investigated the floristic affinities between the Chinese and Australian floras, which represent much of the diversity of the floras of East Asia and Australasia, respectively. Based on a comprehensive genus level phylogeny of the global seed plants and the literature survey of biogeographic studies for the shared genera, we explored the evolutionary relationship between the two floras throughout geological times. Our results suggested that most exchange came up after the Miocene when the emerging islands of Southeast Asia reduced the geographical isolation between the two floras. We also integrated the distribution data to show the spatial pattern of the shared components and correlate the environmental factors which could have impact on migration success. Along with the identification of preference for long life-span and tropical traits, the significant role of habitat filtering during the exchange process between the two floras was indicated.

**S.60 BARK STRUCTURE: EVOLUTIONARY, FUNCTIONAL AND ECOLOGICAL IMPLICATIONS**

**S.60.1 Bark architecture: relationships between appearance and microstructure of covering tissues**

Alexei Oskolski¹

1 Department of Botany and Plant Biotechnology, University of Johannesburg, Johannesburg, South Africa

The relations between macro- and microstructure of bark are poorly explored; the most important contri-
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bution has been made by T.C. Whitmore (1962). The bark appearance is largely determined: (1) by the ability of the outermost layers of bark to maintain its continuity in the course of dilatation, and (2) by the presence or absence of separation layers, i.e., the layers of fragile tissues enabling a regular abscission of outer portions of bark. Diverse barks can be classified into four major architectural types (stretched, exfoliating, furrowed and peeling barks) by possible combinations of these conditions. Stretched (e.g., *Adansonia digitata*) and exfoliating barks (e.g. *Celtis africana*) share the ability to conspicuous expansion, usually with lenticels and eye-like markings. The stretched barks have smooth surface, whereas the exfoliating ones bear superficial scars of fallen scales. These barks share a thin periderm underlaid with parenchymatous layer. Supposedly, these architectural types are associated with photosynthetic ability and gas exchange between stem tissues and environments. The furrowed (e.g., *Quercus suber*) and peeling (e.g., *Buddleja saligna*) barks share prominent vertical fissures, without lenticels and eye-like markings. The furrowed barks lack separation layers; they are mostly covered by conspicuous persistent rhytidome or thick single periderm. Such bark architecture can be associated with fire protection as well as with decline of litter accumulation. The peeling barks are distinctive by detachment of relatively thin strips. Their periderms usually serve as separation layers whereas the collapsed phloem perform protective function; occasionally (e.g., *Vitis vinifera*), the functions of periderm and phloem are allocated in the opposite way. The peeling barks are hardly suitable for colonization by epiphytes. Several ontogenetic trends in age transformation of bark types were found. Estimation of bark architectural types along with the bark thickness is a promising approach in ecological research.

## S.60.2 Bark anatomy diversity in Mediterranean trees and shrubs

Alan Crivellaro¹

1 Forest Biometrics Laboratory, Faculty of Forestry, "Stefan cel Mare" University of Suceava, Suceava, Romania.

Scientists often correlate plant stem anatomical features and physical and biotic factors in the nearby environment. These relationships form a basis to hypothesise adaptive strategies as drivers of much of the anatomical diversity that has resulted

through evolution. In plant stems, the role of bark encompasses conductive, mechanical, and other physiological functions performed by specifically evolved cell types and their arrangements, thus offering diverse bark anatomies. The extensive plant material collected and anatomically described from the island of Cyprus offered a unique opportunity to analyse the bark anatomy of trees, shrubs, dwarf shrubs, and climbers for ecological trends. This study presents bark anatomical trends I identified by analysing the entire woody flora of a geographically well-defined region. I present how bark features of sieve tube morphology and distribution, sclerenchyma presence and arrangement, rays, phellem, phelloderm, crystals, secretory structures, and appearance under polarised light vary in different lifeforms and environments.

## S.60.3 Bark anatomy: what to expect from above- and below-ground in Cerrado species community?

Carmen Regina Marcati¹, Paula Cristina Benetton Vergilio², Julieta Alexandra Rosell³

1 Laboratório de Anatomia de Madeira e Casca, Departamento de Ciência Florestal, Solos e Ambiente, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Botucatu, Brasil. 2 Colegiado de Ciencias Biológicas, Universidade Estadual do Paraná, Paranaguá, Paraná, Brasil. 3 Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico

Covering roots and stems of woody plants, bark is a structurally complex system with functions ranging from conducting photosynthates, and other compounds, to protect the plant. Bark is composed mainly by the secondary phloem, arising from the cambium, and the periderm, arising from the phellogen. Although variation in bark structure across species has been widely examined, little is known about the patterns of bark variation across woody organs. Structural and functional variation would be expected between bark of roots and stems in fire-prone plant communities as a result of the contrasting selective regimes experienced by these above- and below-ground organs. We tested this hypothesis by comparing bark anatomical and functional traits between coarse roots and main stems of species from the Brazilian savanna (Cerrado), the most frequently burnt vegetation globally.
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We sampled the barks from coarse roots and main stems of 15 species of trees and shrubs with high phylogenetic diversity and followed standard anatomical techniques. We observed that the secondary phloem is similar between roots and stems, except that rays in roots were taller than stems suggesting adjustments in radial conduction, and storage in roots, likely associated with resprouting after fire and drought tolerance. The periderm showed more protective traits in stems, mainly higher phellem development, indicating protection against fire. This was observed since the formation of the first periderm, and also when rhytidomes were present. These data indicate that, although the camium is barely influenced by its position in different organs, the phellogen is influenced by the environmental differences to which the organ is exposed.

## S.60.4 Shoot-length Scaling of phloem anatomical traits in angiosperm woody species

Yan Wang¹, Alan Crivellaro², Jiri Dolezal³,⁴, Patrick Heuret⁵, Sandrine Isnard⁵, Johannes Liesche⁶, Olivier Maurin⁷, Yann Salmon¹

1 University of Helsinki, Helsinki, Finland. 2 Stefan cel Mare University of Suceava, Suceava, Romania. 3 Institute of Botany, Czech Academy of Sciences, Třeboň, Czech Republic. 4 University of South Bohemia, České Budějovice, Czech Republic. 5 AMAP, Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France. 6 University of Graz, Graz, Austria. 7 Royal Botanic Gardens, Kew, Richmond, UK

Studying the anatomical structure of phloem contributes to our comprehension of how phloem transport plays a role in the ecological success of species. Additionally, integrating both xylem and phloem traits enhances our understanding of how plants strategically adapt their morphological and anatomical features to diverse climates. In recent years, the importance of the scaling relationship between stem length and the size of xylem and phloem conduits has been highlighted for conducting more precise ecological studies. For some species, it has been observed that the intra-specific variance in vessel and sieve element size is more influenced by stem length than by climate. Further, stem length dominates inter-specific variance of vessel traits compared to species habit climate. However, the extent to which climate contributes to the inter-specific vari-

ability of phloem anatomical traits is not well investigated. The aim of our study is to examine stem anatomical traits of woody angiosperm species in relation to sample distance from apex and their native climate factors across different biomes. We collected stem cross-section images of species from a wide range of climates. We measured the size and frequency of sieve elements and vessels of outer layer rings. The optimum climate for species was extracted from CHELSA V2.0 based on their occurrence records on GBIF. Our preliminary result shows that when data from all species are aggregated, the radius of sieve elements follows a power law with distance from the apex. After correcting for the scaling factor and phylogenetic correlation, both temperature from the wettest quarter and precipitation in the warmest quarter are related to the radius of the sieve tube element. Our study demonstrates the importance of considering scaling geometry when conducting ecological research on anatomical traits. It also suggests that different phloem traits enable various species to cope with distinct environmental conditions.

## S.60.5 Modes of smooth bark formation

Ekaterina L. Kotina¹,², Anna V. Stepanova¹,³

1 Komarov Botanical Institute, St. Petersburg, Russia. 2 Saint-Petersburg State Forest Technical University, St. Petersburg, Russia. 3 The State Hermitage museum, St. Petersburg, Russia

Among the conifer and angiosperm trees, the appearance of bark can vary in a wide range from deeply fissured to smooth one. The bark surface can remain smooth if its outer layers are stretched and/or divided in response to continuous bark increases in circumference as tree grows. We studied different modes of smooth bark formations in several tropical, subtropical (e.g., Adansonia, Commiphora, Euphorbia, Ekebergia, Heteromorpha, Trichilia, Steganotænia, Sesamothamnus, Vachellia, etc.) and temperate (Betula, Populus, Salix) taxa. Most of these studied taxa share relatively narrow outer bark (OB) and much wider inner bark. The OB usually consists of a thin periderm with lenticels on the surface and a parenchymatous cortex or pseudocortex whose cells contain chloroplasts. This is why we can see a green underlain layer after scraping of bark. This suite of traits is apparently associated with the stem photosynthesis. The anticlinal divisions and tangential stretching of periderm cells, formation of lenticels, and superficial initiation of arc-like periderms can contribute to the maintenance of continuous OB. The sloughing of smooth bark can
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be performed by peeling or weathering of outermost phellem layers, or by abscission of thin scales formed by superficial periderms. No prominent rhytidome containing the significant amount of non-conducting secondary phloem found in smooth barks. Their cortex or pseudocortex show meristematic activity, occasionally with formation of dilatation meristems. Shifts from smooth bark to furrowed or tessellated one occur in the older portions of stems in most studied species.

## S.60.6 Patterns and causes of carbon allocation to bark across species and ecosystems

Julieta A. Rosell¹, Karen Vázquez¹, Mark E. Olson², Susanne Vetter³, Carmen R. Marcati⁴, Guillermo Ángeles⁵

¹Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico. ²Instituto de Biología, Universidad Nacional Autónoma de México, Mexico City, Mexico. ³Rhodes University, Makhanda, South Africa. ⁴Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Botucatu, Brasil. ⁵Instituto de Ecología AC, Xalapa, Mexico

Bark is a conspicuous part of woody stems, but a poorly understood one, especially in comparison with wood. Bark includes the tissues outside the vascular cambium and can be divided, from a functional point of view, into an inner mostly living region (inner bark, IB) and an outer dead region (outer bark, OB). There

has been a recent surge of interest in bark functional ecology, but biologists are still far from understanding why some woody plants invest more or less carbon in IB and OB. Bark and wood thickness or cross-sectional areas are good proxies of relative carbon investment, because the density of both tissues varies strongly. We review the main drivers of IB and OB thickness and area across species and ecosystems at the global level, integrating across-species and ontogenetic approaches. Across mature individuals, across species and environments, woody species allocate more carbon to IB in more seasonal environments in which higher storage of water, non-structural carbohydrates, and nutrients is of selective importance, whereas they allocate more carbon to OB as fire frequency increases. In turn, ontogenetic approaches (along stems or across conspecifics of differing sizes) underscore the role of storage but also of metabolic demands as crucial drivers of allocation in the secondary phloem, a tissue that includes the photosynthate-translocating tissue and a large fraction of axial and radial parenchyma. Regarding OB, ontogenetic approaches show that very frequent fire drives an isometric pattern of carbon allocation to OB along stems. Ontogenetic approaches have not only confirmed across-species patterns, but have also contributed to disentangling the functional roles of poorly-understood bark regions such as the phelloderm and the cortex. Further understanding of the remarkable diversity of bark demands a combination of ontogenetic and across-species approaches to the measurement of structural and functional traits.

## S.61 NEOTROPICAL BOTANICAL INVENTORIES: DOCUMENTING WHAT IS LEFT? PERSPECTIVES FROM ACROSS TROPICAL AMERICAS. SESSION 1

### S.61.1 Ferns of Colombia: Accelerating lineage discovery to document Neotropical fern diversity

Alejandra Vasco¹, Weston Testo², Michael Sundue¹,³, Susana Vega⁴, Sarah Morris², Lucía Vargas¹,⁵, Kimberlie Susan¹

¹Botanical Research Institute of Texas, Fort Worth, USA. ²University of Vermont, Burlington, USA. ³Royal Botanic Garden Edinburgh, UK. ⁴Universidad de Antioquia, Medellín, Colombia. ⁵Texas Christian University, Fort Worth, USA

With more than 1450 known species, Colombia harbors fern diversity that is unparalleled elsewhere in the Americas. However, fern diversity in Colombia remains poorly known: nearly half of the species in the country have been collected only a handful of times, and most species have never been studied
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in an evolutionary context. The true richness of Colombia's fern flora is surely much higher than what is known today — likely there are hundreds of species that remain either unreported for the country or are still awaiting scientific description. The Ferns of Colombia project, funded by the National Science Foundation of the United States, aims to improve our understanding of Colombian fern diversity through collaborative research involving Colombian and international pteridologists. Our research focuses on four key objectives (1) Addressing major gaps in our knowledge of Colombia fern diversity, (2) Generating unified taxonomic resources for the ferns of Colombia, (3) Producing genomic resources for the ferns of Colombia, and (4) Integrating objectives 1-3 to accelerate lineage discovery and taxonomic research on Colombian ferns. Here we present the progress and some of the most exciting results of this project, which include new species discoveries, new species records for the country, identification of hybrids, and assessments of the extinction risk for selected species using the IUCN Red List Categories and Criteria. These results are the products of three field expeditions, visits to herbaria in the United States and Colombia, and the training of both undergraduate and graduate students. Outreach and networking efforts aimed at establishing a community dedicated to the study and conservation of Colombian ferns have played a crucial role in achieving our goals.

## S.61.2 Flora Mesoamericana: a long process with a lasting legacy

Carmen Ulloa Ulloa¹, Héctor M.

Hernández², Fred Barrie¹, Gerrit Davidse¹,

Sandra Knapp³

1 Missouri Botanical Garden, Saint Louis, Missouri, United States. 2 Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico. 3 Natural History Museum, London, UK.

Flora Mesoamericana is an international collaborative project organized by the Missouri Botanical Garden, the Institute of Biology of the Universidad Nacional Autónoma de México and the Natural History Museum in London. Its main objective is to carry out a monographic inventory of the vascular plants existing in the Mesoamerican region, based on a critical analysis of the best available information. Our current estimate is 20,119 species of vascular plants occur in the region, 41 of which are endemic (8,222 spp.). According to the

definition established by the organizers, Mesoamerica extends south of the Isthmus of Tehuantepec to and including Panama, with a total area of 778,238 km². In this presentation, a brief account of the history of the project will be given. Likewise, some aspects of its organization, the working method and the results achieved will be described, as well as how the information contributes to larger projects like the World Flora Online. The first volume was published in 1994 and a total of eight volumes have been printed to date, treating 138 families, 1,724 genera, and 11,998 species, representing a 60% of the estimated number of species in the flora. The contents of all volumes, published in Spanish, are also available in a slightly different format on the Internet (http://www.tropicos.org/Project/FM). The progress to date has only been possible thanks to the generous participation of 246 botanists from numerous institutions around the world. Based on the current production rate, we estimate that the remaining five volumes will be released over the course of the next 10 years.

## S.61.3 Documenting the multiple dimensions of the Amazonian plant diversity

Domingos Cardoso¹,², Rafaela

Campostrini Forzza¹,³

1 Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil. 2 Instituto de Biologia, Universidade Federal da Bahia, Salvador, Brazil. 3 Instituto Chico Mendes de Conservação da Biodiversidade, Prado, Brazil

Documenting the multiple dimensions (classification, distribution, ecological interactions, and evolutionary history) of the remarkable Amazonian plant biodiversity has been one of the greatest challenges of botanical science, especially in the face of global threats of tropical forest destruction and climate change. While the Amazon is recognized as the home to the world's largest tropical rain forest biome and plays a crucial biogeochemical role in regulating the global climate through essential ecosystem services, little is known about the plant biodiversity itself, the leading player in the evolutionary theater of this majestic forest. For instance: how many different tree species are there throughout the Amazon? When and where did they evolve? What are the primary ecological and biogeochemical processes driving their evolution? Addressing such questions requires a synergistic compromise between plant systematists and tropical ecologists. However, recent debates on the number of plant species across the Amazonian rain forests have relied heavily
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on model estimates, neglecting published taxonom-
ically verified checklists. Ongoing taxonomic and flo-
ristic efforts across Latin America, such as the collab-
orative and dynamic web-based platform of the Flora
e Funga do Brasil, are the best way to track progress
and updates in near-real time. Detailed taxonomic
monographic and phylogenetic works including newly
collected specimens and genome-wide sequencing
of specimens already held in global herbaria have re-
vealed new species and genera, and how domestica-
tion has impacted their evolutionary history. Sustained
investment in taxonomy, herbarium collections, virtu-
al herbarium platforms, new collections through field
work, and massive DNA sequencing are fundamental
in order to document and answer large scientific ques-
tions on the origin, evolution, and ecology of the mega-
diverse Amazon flora in its entirety.

S.61.4 Plants of the ring:
Botany of Mexican cenotes

Manuel Luján¹, Rodrigo Duno De Stefano²,
Ivón Ramírez Morillo², Alfredo Dorantes²,
Nestor Raigoza Flores², Pedro Zamora
Crescencio³, Eliana Noguera-Savelli⁴,
Germán Carnevali Fernández-Cocha²

1 Royal Botanic Gardens, Kew, UK. 2 Herbario CICY,
Centro de Investigación Científica de Yucatán,
Mérida, México. 3 Herbario UCAM, Universidad
Autónoma de Campeche, Campeche, México. 4
Consejo Nacional de Ciencia y Tecnología, Colegio
de Postgraduados Campus Campeche, Cham-
potón, México

Sixty-five million years ago, a meteorite struck the Earth
near the Yucatán peninsula in south-eastern Mexico,
causing global-scale bioclimatic changes that lead
to the extinction of all non-avian dinosaurs. Deep and
large water-filled sinkholes called cenotes formed
along the edge of the crater basin, making a ring
around the center of the crater. Cenotes are striking el-
ements of the natural landscape in the Yucatan pen-
insula and were sacred worship places for the Mayan
culture. Urban development is threatening cenotes as
they are being polluted or transformed during road
and railway constructions. The flora associated with
cenotes remain largely undocumented, and it is un-
known how many native and endemic plant species
thrive around these formations. We have undertaken
floristic inventories in several cenotes in the peninsula
including localities in the states of Campeche and Yu-
catan to collect plant data and materials to prepare
herbarium specimens. This talk shows our preliminary

results on the floristic composition and structure of the
plant communities associated with the cenotes. We
also highlight the importance of building compelling
narratives around floristic research projects to secure
funding as well as the involvement of relevant stake-
holders including local communities and institutions.

S.61.5 Monitoring tree diversity across the Andes: the Madidi Project and the Red de Bosques Andinos

J. Sebastián Tello¹, Cecilia Blundo², Luis E. Gámez Álvarez³, Luis Daniel Llambi⁴, Francisco Cuesta⁵, Leslie Cayola¹,⁶, Agustina Malizia, Julieta Carilla², Oriana Osinaga Acosta², Alfredo F. Fuentes¹,⁶

1 Latin America Department, Missouri Botanical Garden, St, Louis, MO, United States of America. 2 Instituto de Ecología Regional, Universidad Nacional de Tucumán - Consejo Nacional de Investigaciones Científicas y Técnicas, Tucumán, Argentina. 3 Laboratorio de Dendrología, Facultad de Ciencias Forestales y Ambientales, Universidad de Los Andes, Mérida, Venezuela. 4 Consorcio para el Desarrollo Sostenible de la Ecorregión Andina, Quito, Ecuador. 5 Grupo de Investigación en Biodiversidad, Medio Ambiente y Salud, Universidad de Las Américas, Quito. 6 Herbario Nacional de Bolivia, La Paz, Bolivia.

Botanical inventories are crucial for understanding,
managing, and protecting biodiversity. Tropical regions,
despite centuries of study, remain poorly known, and
their botanical diversity is undocumented. Collabora-
tion to develop large-scale, long-term research pro-
grams is vital in this monumental task. In Bolivia, the
Missouri Botanical Garden and the Herbario Nacion-
al de Bolivia have established a program focused on
documenting and conserving plant diversity. A corner-
stone of this initiative is the Madidi Project on the east-
ern slopes of the Bolivian Andes. This project merges
traditional botanical exploration with a vast network
of forest plots, yielding information from nearly 60,000
collections, 200,000 surveyed trees, and 500 forest plots
that document more than 3,000 species, including ap-
proximately 200 new to science. A significant effort has
been made to standardize species names in this large
dataset, a common challenge in such endeavors. The
data informs various aspects of plant biodiversity, in-
cluding diversity, ecology, and evolution. It also aids in
assessing species' conservation statuses and provides
essential biodiversity information to local policymak-
ers. While impactful, the Madidi Project covers a frac-
tion of the Tropical Andes, a global biodiversity hotspot.
To address larger-scale biological and conservation
challenges, researchers from multiple countries estab-
lished the Red de Bosques Andinos (RBA). This network
includes hundreds of forest plots spanning from Vene-
zuela to Argentina and involves numerous forest biolo-
gists. Its formation, primarily by scientists from Andean
nations, represents a formidable regional collaboration.
The RBA generates vital research on forest ecology and
responses to environmental threats. Both the Madidi
Project and the RBA exemplify the importance of col-
laboration and capacity building in long-term forest
monitoring and large-scale biodiversity inventories
more generally.

S.61.6 How effective have
botanists been at sampling
Neotropical plant diversity

Alexandre K. Monro¹, Pablo Hendrigo Alves de Melo², Manuel Lujan¹, Nadia Bystriakova³

1 Royal Botanic Gardens, Kew, Richmond, UK. 2 In-
stituto Federal de Educação, Ciência e Tecnologia
de Minas Gerais, Campus Avançado Piumhi, Minas
Gerais, Brazil. 3 The Natural History Museum, Lon-
don, UK

For the most part, botanical inventories in the Neo-
tropics have occurred in a haphazard, uncoordinated
manner and lacked explicit sampling strategies. We

assemble a cleaned version of GBIF biological collections data for the Neotropics to evaluate the gaps and biases in sampling effort to date with respect to predicted diversity, evolutionary distinctness, extinction threat, habitat type and ecosystem services. Whilst not complete, GBIF represents the single most important source of occurrence data for the Neotropics, comprising ca 8 million occurrence records (tracheophyte preserved specimens with coordinates). 'Preserved specimens' the data class corresponding to herbarium collections, comprises occurrence records backed by a physical specimen whose identity can be verified. We downloaded and parsed all occurrence records into unique collection events (Hendrigo Alves de Melo et al, 2023, matched these to a unified taxonomic backbone (World Checklist of Vascular Plant Names, Govaerts et al., 2021) and then projected them onto a map of the Neotropics divided into grid cells of 10 x 10 km. We then overlaid this map with the observed tracheophyte species richness, IUCN habitat classes. Keith et al. (2020), estimates of predicted species richness, the evolutionary lineage coverage, frequency of threatened species and the estimates of carbon and water value (Jung et al. (2021). This enabled us to identify bias in the sample effort of previous botanical inventories in respect of all the above, and to identify the major gaps in occurrence data for the region.

References: Govaerts et al. (2021) https://doi.org/10.1038/s41597-021-00997-6, Hendrigo Alves de Melo et al. (2023) https://doi.org/10.21203/rs.3.rs-3579370/v1. Jung et al. (2021) https://doi.org/10.1038/s41559-021-01528-7. Keith et al. (2020) https://doi.org/10.2305/IUCN.CH.2020.13.en

S.62 EVOLUTION OF KEY INNOVATIONS IN
LAND PLANTS REVEALED THROUGH THE LENS
OF EVODEVO. SESSION 1

S.62.1 Transcriptomic
landscape of the hornwort
sporophyte

Manuel Waller¹,², Ueli Grossniklaus²,³,
Karen Renzaglia⁴, Eftychios Frangedakis⁵,
Keiko Sakakibara⁶, Kazune Ezaki⁶, Péter
Szövényi¹,²

1 Department of Systematic and Evolutionary Bot-
any, University of Zurich, Zurich, Switzerland. 2 Zu-
rich-Basel Plant Science Center, Zurich, Switzerland.
3 Department of Plant and Microbial Biology, Uni-
versity of Zurich, Zurich, Switzerland. 4 Department
of Plant Biology, Southern Illinois University, Illinois,
USA. 5 Department of Plant Sciences, University of
Cambridge, Cambridge, UK. 6 Department of Life
Science, Rikkyo University, Tokyo, Japan

The diploid spore producing sporophyte of land plants
is thought to have been interpolated into a primarily
haplontic ancestral life cycle as an adaptation to life
<figure><img src="image_156.png" /></figure>

on dry land. However, between the two monophy-
letic land plant clades, the bryophytes and vascular
plants, sporophyte evolution has followed contrasting
trajectories. Bryophyte sporophytes are nutritionally
dependent on the gametophyte, uniaxial and mono-
sporangiate, while vascular plant sporophytes have
evolved complex branched body plans with a variety
of lateral organs to become nutritionally independent.
Little is known about how regulatory processes of spo-
rophyte development have evolved and contributed
to the diversification of sporophyte functions and mor-
phology. Comparative analyses on sporophyte devel-
opment and conclusions on developmental homolo-
gies have primarily been drawn using the model moss
Physcomitrium patens and the liverwort Marchantia
polymorpha, in comparison to the well-studied devel-
opment of flowering plants. However, sporophytes of
the three lineages of bryophytes exhibit considerably
different growth patterns and insights into shared reg-
ulatory mechanisms of sporophyte development can
only be achieved by simultaneously investigating all
three bryophyte lineages. With the recent establish-
ment of Anthoceros agrestis as a hornwort model, ge-
nomic and sporophyte transcriptomic data has be-
come available. Therefore, to gain insight into shared
and divergent regulatory mechanisms among liver-
worts, mosses, and hornworts, we compared sporo-
phyte specific gene expression across the three bryo-
phyte models by creating and analyzing sporophyte
and gametophyte enriched transcriptome datasets
for M. polymorpha, P. patens and A. agrestis. Further-
more, using laser capture microdissection, we gener-
ated tissue-specific transcriptomes for distinct tissues
within the A. agrestis sporophyte proliferative zone and
analyzed differential gene expression between these
sporophyte tissues, to provide the first insight into
the genetic control of hornwort sporophyte develop-
ment. Using fluorescent reporter and overexpression
lines we provide our first results concerning the ances-
tral function of key developmental genes in the spo-
rophyte development of bryophytes and land plants.

S.62.2 The evolution and
development of sporangia
– the fundamental
reproductive organ of land
plant sporophytes

Barbara A. Ambrose¹

1 New York Botanical Garden. Bronx, NY, USA

A salient feature of the diploid sporophyte is the de-
velopment of the sporangium, the fundamental re-
productive structure of all land plants. Whether the
structure is a cone, strobilus, or flower – all are clusters
of sporangia. The sporangium is where meiosis occurs
to produce spores, marking the transition between the
diploid and haploid phases of the plant life cycle. In all
land plants, sporangium development begins when a
somatic cell is specified to be reproductive and then
undergo a series of stereotypical divisions, and cell fate
decisions that gives rise to the sporangium. The de-
velopmental anatomy of sporangia has been studied
across land plants. From an evolutionary point of view,
sporangia are key to land plant success. The evolution
of distinct sporangia (heterospory) and retention of the
gametophyte evolved three times independently and
was a necessary innovation for the subsequent evolu-
tion of the seed. The well-known nucellus and pollen sac
are the sporangia of flowering plants, and the molecu-
lar genetics of their development has been well studied,
particularly in *Arabidopsis thaliana*. Despite its funda-
mental importance, we lack a comprehensive under-
standing of the evolutionary developmental genetics of
sporangia development across land plants. To fill this
gap, we are investigating the development and molec-
ular genetics of sporangia in lycophytes and ferns with
a focus on the fern model system, *Ceratopteris richardii*.
We are studying the development of sporangia in lyco-
phytes and ferns using histochemical staining and mi-
croscopy. We are investigating the molecular genetics
of *C. richardii* sporangia development using transcrip-
tomics and a candidate gene approach. Despite differ-
ences in sporangia cell patterning between *A. thaliana*
and *C. richardii*, we found homologous genes pattern
sporangia in both species. This suggests that there is
a common genetic module that patterns all sporangia
and provides a framework for understanding their evo-
lution and development.

S.62.3 Origin and Expression
of the silencing peptide
RADIALIS in Gymnosperms
suggests a role in seed and
fruit development.

Aniket Sengupta, Dianella Howarth¹

1 Biological Sciences, St. John's University, New York,
USA

An ongoing question in biology is how gene duplica-
tion and changes in gene expression may be associ-
<figure><img src="image_157.png" /></figure>

ated with morphological shifts. One major innovation in plants is the development of ovules and seeds, traits that evolved in the ancestor of all seed plants. Within seed plants, flowers and fruits are synapomorphies arising within angiosperms, while gymnosperms retain the ancestral absence of these structures. Known floral patterning transcription factors RADIALIS and DIVARICATA are closely related MYB proteins whose competitive interaction is associated with the development of carpels/fruits and the establishment of bilateral symmetry in zygomorphic flowers. RADIALIS has been described as a silencing peptide that is a truncated paralog of DIVARICATA. Through a Bayesian phylogenetic approach, we demonstrate DIVARICATA genes underwent two rounds of duplications at the base of vascular plants forming three clades: DIV-A, DIV-B, and DIV-C. We show that RADIALIS genes evolved from DIV-C genes at the base of seed plants through a premature stop codon that was likely generated by a single-base substitution. This suggests that the RADIALIS-DIVARICATA competitive interaction likely evolved once, at the base of seed plants. We also surveyed the expression pattern of these genes for the first time in a gymnosperm, Ginkgo biloba. We find that Ginkgo biloba RADIALIS genes are expressed widely but often have higher expression in reproductive organs, especially in megasporangia. This is particularly interesting given that the megasporangium is the evolutionary precursor of carpels/fruits. A key innovation associated with megasporangia of seed plants is that they enclose ovules or seeds. Our work provides suggestive evidence that the evolution of seed habit and the later origin of fruits may be associated with the origin of the silencing peptide RADIALIS

## S.62.4 Untangling the developmental genomics of the unique reproductive structures in Gnetales

Cecilia Zumajo-Cardona¹, Dennis W. Stevenson², Natalia Pabon-Mora³, Barbara A. Ambrose²

1 Università degli Studi di Milano, Milano, Italy. 2 New York Botanical Garden, Bronx, NY, United States. 3 Universidad de Antioquia, Medellín, Colombia

The seed is a synapomorphy of all extant seed plants that develops from an ovule, i.e., an integumented megasporangium. As sporangia are conserved throughout vascular plants, the origin of the integument is a defining step in seed evolution. There are some key differences in the number of integuments present in

seed plants as well as accessory structures that cover seeds in gymnosperms and some angiosperms. Due to extra structures covering the nucellus, the ovules of Gnetales (*Ephedra*, *Gnetum*, *Welwitschia*) are strikingly different from those of all other extant gymnosperms. In the genera *Ephedra* and *Welwitschia* two envelopes cover the nucellus in contrast to *Gnetum* that has three envelopes. In all three genera of Gnetales, it is generally agreed that the inner envelope is homologous to an integument that elongates and forms the micropyle in other gymnosperms. The homology of the additional envelopes remains equivocal, but it is not debated that these form a unique seed coat in the Gnetales. With an emphasis on the ovulate reproductive structures, here we present the morphoanatomy of the striking differences in the ovulate reproductive structures of representatives of the three gnetalean genera. With a search in our own generated transcriptional data, we present the differences and similarities with what is already known for angiosperms. Developmental studies on the ovule of *Gnetum gnemon* suggests that canonical genes involved in integument development are not involved in the development of the additional envelopes, suggesting that at least from a molecular perspective there are major differences when compared to angiosperms. A holistic approach involving different perspectives may be required for a better understanding of the complex relationships and evolutionary history of the Gnetales.

## S.62.4 Reconstructing the origin of reproductive function for a flower development gene in ferns

Hannah McConnell¹, Jancee Rice Lanclos¹, Nicholas Gjording¹, Genevieve Stockman¹, Julin Maloof², Andrew Plackett³, Verónica S. Di Stilio¹

1 Department of Biology, University of Washington, Seattle, USA. 2 Department of Plant Biology, University of California, Davis, USA. 3 School of Biosciences, University of Birmingham, Birmingham, UK

The transition from vegetative growth to flowering in the diploid sporophyte of angiosperms is partly controlled by *LEAFY* (*LFY*), a well-characterized flower meristem identity gene. Less is known about whether *LFY* plays a role in the haploid gametophyte phase and what that role might be. *LFY* orthologs also exist in non-flowering plants, and in mosses, they control the first mitotic division of the zygote. Recent evidence indicates that *LFY*
has a vegetative role in fern meristems, but it is unclear where its reproductive function arose. Here, we continue to bridge the gap in investigations into this key floral regulator between mosses and angiosperms to reconstruct the evolution of *LFY*'s reproductive function across land plants. We ask whether *LFY* was co-opted into its specialized flowering function from its previously identified generalized role in regulating meristems by characterizing its two paralogs in the model fern *Ceratopteris richardii*. Transgenic ferns constitutively overexpressing *LFY* orthologs experienced delayed gametophyte fertilization, suggesting a novel role in gametophyte reproduction, and produced overgrown lateral meristems and decreased leaf compounding in sporophytes, providing additional support to the previously characterized vegetative meristem function. Overall, our results suggest that *LFY*'s reproductive role in angiosperm sporophytes may have been ancestrally co-opted from the gametophyte while also supporting previous evidence of their involvement in cell division in both phases of the fern life cycle.

**S.62.5 Investigating the origins of phloem development**

Rafael Cruz, Erica de Leau¹, Erin Ryan¹, Kuo Xu¹, Zishan Fu¹, Alexander J. Hetherington¹

¹Institute of Molecular Plant Sciences, University of Edinburgh, Scotland, UK

Food-conducting cells are present in the major branches of the land plants phylogeny, and specialized phloem tissue is a predicted synapomorphy of the vascular plants. Little is known about the origins of phloem, and when looking at all groups, especially seed-free plants, we can find a great diversity of phloem structure considering the organization of sieve pores and associated parenchyma cells. However, the molecular toolkit necessary for phloem development is mostly described for flowering plants, particularly *Arabidopsis*. To better understand the evolution of genes related to phloem development in other groups, we conducted phylogenetic analyses of some genes related to phloem development. Our gene trees demonstrate that homologs of *OCTOPUS* (related to phloem cell polarization) and *NAC 45/86* (related to cytoplasm and nucleus dissolution) appeared in the ancestor of vascular plants. The main regulator of *Arabidopsis* phloem development, *ALTERED PHLOEM DEVELOPMENT*, a MYB Golden-2-like protein, upregulates several genes in the phloem development pathway (including *NAC 45/86*). The ancestral copy of these proteins was present in the common ancestor of land plants. We are now exploring the expression of APL homologs in ferns and lycophytes, and we have identified seven and two APL homologs for the experimental models *Ceratopteris richardii* and *Selaginella moellendorffii*, respectively. Our preliminary data shows the expression of one of the APL homologs in the developing vascular system of *S. moellendorffii*. These findings provide insights into a possibly conserved regulatory network governing phloem development, shedding light on their evolution across diverse plant lineages.

**S.63 PLANT DIVERSITY, BIOGEOGRAPHY AND EVOLUTION IN THE TROPICS FOR CONSERVATION, RESTORATION AND SUSTAINABLE USE. SESSION 1**

**S.63.1 The contribution of indigenous and local people to cataloguing life on Earth**

Juan C. Copete¹*, Alred Kik², Vojtech Novotny², Rodrigo Cámara-Leret¹

¹Department of Systematic and Evolutionary Botany, Zurich, Switzerland. ²University of South Bohe-

mia, Ceske Budejovice, Czech Republic. ³Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic

Indigenous and local peoples' (ILPs) [NV1] contributions to cataloguing life on Earth have been significant but remain under-appreciated. After over 200 years of insights from ILPs to science, the potential contribution of ILPs to current biodiversity research and conservation remains underutilised. The traditional knowledge of ILPs face growing cultural and
<figure><img src="image_158.png" /></figure>

biological threats. Fostering greater participation of ILPs in research would make science more efficient and conservation more sustainable while also slowing down the erosion of traditional knowledge and skills of ILPs, but formidable obstacles to such participation remain.

## S.63.2 Conservation gap analysis of Mesoamerican oaks: establishing priorities for conservation

Kate Good¹, Allen Coombes², Susana Valencia Avalos³, Maricela Rodríguez-Acosta⁴, Emily Beckman Bruns¹, Silvia Alvarez-Clare¹

1 The Morton Arboretum, Lisle, USA. 2 Benemérita Universidad Autónoma de Puebla, Puebla, Mexico. 3 Universidad Nacional Autónoma de México, Mexico City, Mexico. 4 The Global Conservation Consortium for Oak, Mexico and Central America, Puebla, Mexico

Mesoamerica is a global center for oak biodiversity (genus Quercus), with an estimated 164 species in Mexico alone. Despite this incredible diversity, for many species, little is known regarding population size, trends, occurrence, or threats. There is an urgent need to coordinate and prioritize conservation action for both *in situ* and *ex situ* populations. We conducted a conservation gap analysis of 59 threatened and Data Deficient species of Mesoamerican oaks to estimate the geographic and ecological representation of species in *ex situ* collections. For species without population-level genetic data, this is a useful proxy to estimate the genetic representation of *ex situ* collections. Between 2017 and 2022 we distributed surveys to *ex situ* institutions with a request for their Quercus accessions data. There were 197 institutions that reported living collections of at least one Mesoamerican oak, a majority of which are in the United States (49%) and Europe (32%), with only 5% of the species having at least one collection in Mesoamerica. Twenty-two of our target species are not held in any *ex situ* collections, anywhere in the world. We found that only three of the 59 target species have *ex situ* collections that represent more than 50% of the species' geographic range, and only 19 species have an ecological coverage greater than 50%. Furthermore, approximately one fourth (16/59) of the target species have less than 10% of their native range within protected areas. These results highlight the urgent need for ex-

panding survey and exploration work, increasing representation of oak species in botanic gardens and arboreta, particularly in Mexico and Central America, and identifying priority regions to focus in situ conservation efforts, as well as priority activities for the members of the Global Conservation Consortium for Oak (GCCO).

## S.63.3 Characterizing and explaining diversification in Haitian Coffee agroforestry systems

Millet Claude Patrick¹,²,³,⁴, Allinne Clémentine³,⁴,⁵,⁶, Vi Tram¹,⁸, Marraccini Pierre¹,⁷, Verleysen Lauren⁹,¹⁰, Couderc Marie¹, Ruttink Tom¹⁰,¹¹, Zhang Dapeng¹², Solano-Sanchéz William¹³, Tranchant-Dubreuil Christine¹, Jeune Wesly²,¹⁴, Poncet Valérie¹

1 IRD, UMR DIADE, CIRAD, Univ Montpellier, Montpellier, France. 2 Faculté des Sciences de l'Agriculture et de l'Environnement, Université de Quisqueya, Port-au-Prince, Haiti. 3 ABSys, Univ Montpellier, CIREAM-IAMM, CIRAD, INRAE, Institut Agro, Montpellier, France. 4 CIRAD, UMR ABSys, Montpellier, France. 5 GECO, Univ Montpellier, CIRAD, Montpellier, France. 6 CIRAD, UPR GECO, Montpellier, France. 7 CIRAD, UMR DIADE, Montpellier, France. 8 Agricultural Genetics Institute (AGI), Hanoi, Vietnam. 9 Division of Ecology, Evolution and Biodiversity Conservation, Faculty of Sciences, KU Leuven, Leuven, Belgium. 10 ILVO, Melle, Belgium. 11 Ghent University, Ghent, Belgium. 12 USDA-ARS, SPCL, Beltsville, MD, USA. 13 CATIE, Turrialba, Costa Rica. Pétion-Ville, Haiti

Diversification of cropping systems is a strategy to increase their social and ecological resilience and delivery of ecosystem services. Such practices are prevalent in traditional agroforestry systems, such as those where coffee (*Coffea arabica*) is grown. Indeed, though they face several challenges, Haitian coffee agroforestry systems are important contributors to rural biodiversity and household livelihoods. However, little scientific attention has been paid to these systems. We studied diverse farms in historically important coffee growing regions of northern and southern Haiti and characterized the diversity of several components of their agroforestry systems: coffee plants, shade trees, and associate crops. We tested the relationships between these different levels of diversity and identified key ecosystem services delivered by them, including provision of diversified
farm products and carbon storage. In the case of Arabica coffee specifically (Millet et al. 2023), using targeted genotyping, we found significant genetic diversity and complex varietal mixtures. We show that some coffee farms are repositories of historical, widely-abandoned varieties while others are generators of new diversity through genetic mixing despite Arabica's tendency towards autogamy. In the latter, several varieties are often grown together, often in an uncontrolled manner, and are allowed to crossbreed with recruitment from the seed bank common, explaining the frequent admixture detected. Comparing these results with local, vernacular identifications, we found that the diversity in these systems is often under-estimated. These studies are, to our knowledge, the first to genetically characterize Haitian *C. arabica* and one of very few that have looked at Haitian agroforestry system crop and tree diversity.

References: Millet et al. 2023 Haitian Coffee agroforestry systems harbor considerable, dynamic and under-reported variety mixtures and genetic diversity. PlosOne, in revision.

## S.63.4 Understanding patterns of biogeography and threat of tree species diversity across the Latin American biomes

Karina Banda-R¹,²,³,⁴, Renato A. Ferreira de Lima⁵,⁶, Guilhierme Grittz⁵,⁶, Cecilia Blundo⁷, ⁸, Luis Cayuela⁹, Géraldine Derroire¹⁰,¹¹, Kyle Dexter⁴,¹²,¹³, Moabe Fernandes¹⁴, Claire Fortunel¹⁵, Natalia Norden¹⁶,¹⁷, Susana Rodríguez¹⁷, Carolina Castellanos¹⁷, Roy González-M.⁴,⁶,²⁹, Tamara Heartsill-Scalley¹⁸,¹⁹, Filipe M. França²⁰, Toby Pennington⁴,¹²¹⁴, Oliver Phillips²¹, ²², Ricardo Segovia²³, Hans ter Steege²⁴,²⁵, Jérôme Chave¹¹,²⁶, Adriane Esquivel-Muelbert²¹,²⁷, Cristina López-Gallego²⁸

1 FRB-CESAB: Centre de Synthèse et d'Analyse sur la Biodiversité, Montpellier, France. 2 Helmholtz Centre for Environmental Research GmbH - UFZ, German Centre for Integrative Biodiversity Research, Halle-Jena-Leipzig, Germany. 3 Fundación Ecosistemas Secos de Colombia, Pradomar, Puerto Colombia, Colombia. 4 DRYFLOR-Red Florística Latinoamericana del Bosque Tropical Estacionalmente

Seco. 5 Departamento de Ciências Biológicas, ES-ALQ, University of São Paulo, Piracicaba, Brasil. 6 TreeCo- Neotropical Tree Communities database. 7 Instituto de Ecología Regional, Universidad Nacional de Tucumán, Tucumán, Argentina. 8 RBA-Red Bosques Andinos. 9 BIOTREE.NET-Tree Biodiversity Network. 10 Centre de Coopération Internationale en Recherche Agronomique pour le Développement. 11 Guyafor network. 12 Tropical Diversity Section, Royal Botanic Garden Edinburgh, Edinburgh, UK. 13 School of GeoSciences, University of Edinburgh, Edinburgh, UK. 14 Department of Geography, University of Exeter, Exeter, UK. 15 AMAP (Botanique et Modélisation de l'Architecture des Plantes et des Végétations), Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France. 16 Red BST-Col- Red Bosque Seco Tropical Colombia 17 Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, Colombia. 18 International Institute of Tropical Forestry, USDA Forest Service, Río Piedras, Puerto Rico. 19 Caribbean Foresters. 20 School of Biological Sciences, University of Bristol, Bristol, UK. 21 ForestPlots.net-Rainfor. 22 School of Geography, University of Leeds, Leeds, UK. 23 Instituto de Ecología y Biodiversidad, Concepción, Chile. 24 ATDN- Amazon Tree Diversity Network. 25 Naturalis Biodiversity Center/Free University Amsterdam, Leiden, Netherland. 26 Laboratoire Évolution & Diversité Biologique, CNRS, IRD, Toulouse, France. 27 Department of Geography, School Geography, Earth and Environmental, Birmingham, UK. 28 Instituto de Biologia Universidad de Antioquia Medellin, Colombia. 29 Universidad del Tolima, Ibagué, Colombia

Tropical America has greater biodiversity than any other region of the world, but its biomes are under severe threat from climate and severe land use changes. Over recent years, plot inventory networks have successfully generated syntheses on biodiversity, ecology and ecosystem function. SynTreeSys, a new integrative initiative supported by CESAB (Centre for the Synthesis and Analysis of Biodiversity in France) is gathering knowledge of tree biodiversity across all biomes and gradients of rainfall and climate in Latin America, in order to dissect the patterns of tree diversity, abundance and threats. These inventory plot data offer much to assess species conservation status. Such conservation assessments can be made using herbarium specimen records, but these records have sampling biases and, critically, give no information about species population size and trends. The lack of such basic information prevents us from defining where conservation actions could be strategically implemented to best preserve tree diversity in the region, and to generate future scenarios based on known macroeconomic, climatic and land-use drivers. Here, we present examples from different biomes and regions that examine species' geographic ranges (IUCN criterion
<figure><img src="image_159.png" /></figure>

B), and population sizes and potential declines (criteria A, B and D), following the International Union for Conservation of Nature (IUCN) framework. We show how inventory plot data can be used to estimate tree species population size as has been previously done for the Amazon and Mata Atlantica but across other biomes. Population decline can be estimated by crossing such species abundance maps with layes of vegetation cover change. We show how abundance and population estimates can inform more accurately the conservation status of tropical tree species of all the biomes of Latin America.

**S.63.5 Insights into the history and evolution of African tropical trees through comparative phylogeography**

Olivier J. Hardy¹

1 Université Libre de Bruxelles, Brussels, Belgium

Although tropical Africa is home to the second largest tropical rainforest, the origin and evolution of its rich biodiversity remain poorly studied. However, the accumulation of phylogeographic and population genetic studies on tree species makes it possible to look for general patterns. 1. We found that about a quarter of African tree species studied, as delineated by current taxonomy, contain multiple species following the biological species concept, which might double the tree species richness in Tropical Africa and indicate a trend toward taxonomic over lumping. 2. Genome skimming makes it possible to sequence hundreds of plastomes at a reasonable cost, shedding light on the colonization dynamics of species or genera using time-calibrated phylogenetic models. Major distribution range shifts seemed to have occurred c. 200,000 years ago in several unrelated taxa. 3. The comparison of maternally inherited plastomes and nuclear markers provides information on the respective role of seed and pollen dispersal, and highlights situations of extensive plastid capture, suggesting that certain taxa (e.g. several genera of the Berlinia clade, Dertarioidea, Fabaceae) could evolve as a syngameon. Finally, phylogeographic data on exploited tree species provide key information to conserve their natural populations or design breeding program for plantation of native species.

**S.63.6 Spatial patterns and predictors of seed plants' extinction risks in Asian countries**

Lijing Zhou¹,²,³, Keping Ma¹,², Li Zhu¹,², Guoke Chen¹,², Bo Liu⁴, Hongfeng Wang⁵, Cui Xiao¹,², Yuying Zhao¹,²

1 State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China. 2 China National Botanical Garden, Beijing, China. 3 University of Chinese Academy of Sciences, Beijing, China. 4 Minzu University of China, Beijing, China. 5 School of Forestry, Northeast Forestry University, Harbin, China

Asian countries are experiencing severe biodiversity loss, so it is crucial to develop practical conservation actions and strategies. Threats to species are often dynamic, as their impacts on extinction risk change over time. There is an urgent need to better understand how these factors are interrelated and how they vary spatially with extinction risk. Here, we presented a spatially explicit method to evaluate the dynamic trends and predictors of seed plants' extinction risks across countries, using National Red List data from China, Japan, and Sri Lanka as case studies, by calculating the Red List Index (RLI) and mapping the percentage of seed plants facing increasing risks and pressures. We found overall decrease in extinction risks, however, a substantial number of species, ranging from 328 to 1343 depending on the country, still showed increasing extinction risks. Increasing extinction risks of plants was strongly correlated with changes in threats, such as urban expansion, temperature changes, and tree canopy cover changes, rather than static threat intensity. Specifically, increasing tree canopy cover significantly associated with plant extinction risks in both China and Sri Lanka, where large-scale afforestation and economic forest plantation probably resulted in habitat degradation and species loss. Concerningly, our findings indicated that land-use change was the dominant driver of increased species extinction risk in these two countries, in contrast to climate change in Japan. As governments commit to the Kunming-Montreal Global Biodiversity Framework, we suggest them to make site-specific or taxa-specific policies to ensure the effectively prevention of biodiversity loss.
<figure><img src="image_160.png" /></figure>

# S.64 RECENT ADVANCES IN THE MEGADIVERSE LEGUME SUBFAMILY PAPILIONOIDEAE. SESSION 1

## S.64.1 A new phylogeny of the megadiverse legume subfamily Papilionoideae

Rafaela J. Trad¹, Flávia F. Pezzini¹, R. Toby Pennington¹,², Gwilym Lewis³, Bente Klitgård³, Russell Barrett⁴, Anne Bruneau⁵, Warren Cardinal-McTeague⁶, Domingos Cardoso ⁷, James Clugston⁸,⁹,¹⁰, Manuel de la Estrella¹¹, Ashley N. Egan¹², Colin Hughes¹³, Erik Koenen¹³, Todd McLay¹⁴, Daniel Murphy¹⁴, Matt Renner⁴, Jens Ringelberg¹⁵, Rowan Schley², Mohammad Vatanparast³, Martin Wojciechowski¹⁶, Darren Crayn¹⁷, Olivier Maurin³, Raquel Negrão³, Catherine McGinnie³, Paul Bailey³, William J. Baker³, Félix Forest³, Gregory J. Kenicer¹

1 Royal Botanic Garden Edinburgh, Edinburgh, UK.
2 University of Exeter, Exeter, UK.
3 Royal Botanic Gardens, Kew, Richmond, UK.
4 National Herbarium of New South Wales, Australian Institute of Botanical Science, Mount Annan, Australia.
5 Institut de Recherche en Biologie Végétale, University de Montreal, Montreal, Canada.
6 Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, Canada.
7 Universidade Federal da Bahia, Salvador, Brazil.
8 Royal Botanic Garden Sydney, Sydney, Australia.
9 Montgomery Botanical Center, Coral Gables, United States of America.
10 Hawkesbury Institute for the Environment, Western Sydney University, Penrith, Australia.
11 Universidad de Córdoba, Córdoba, Spain.
12 Utah Valley University, Orem, United States of America.
13 University of Zurich, Zurich, Switzerland.
14 Royal Botanic Gardens Victoria, Melbourne, Australia.
15 School of Geosciences, University of Edinburgh, Edinburgh, UK.
16 Arizona State University, Tempe, United States of America.
17 Australian Tropical Herbarium, James Cook University, Cairns, Australia

Papilionoid legumes occupy every terrestrial biome across a vast array of niches and lifeforms. This characteristic, successful and diverse subfamily (Papilionoideae) is larger than most angiosperm orders and comparable in size to Ericales and Myrtales. The c. 13,800 species constitute around 60% of diversity in the

legume family and their value as crops for food, fodder, medicine, soil nitrification, rose wood timber, and an array of other purposes is huge. Due to its size and, until recently, to technical and cost limitations, studies have mostly focused on resolving relationships within specific clades using chloroplast DNA in the subfamily and an extensive nuclear-based phylogeny is still lacking. Additionally, several studies in the most diverse groups of plants have indicated that discordance between nuclear and chloroplast trees is frequent and that phylogenetic estimates for both are necessary to study the evolution of a group. Thus, having a comprehensive nuclear phylogeny for the subfamily is imperative. To this end, we sampled at least one species for over 95% of the 503 papilionoid genera accepted by the Legume Phylogeny Working Group. DNA extraction, library preparation, hybridization with the Angiosperms353 probe set, and sequencing were conducted as part of the Plant and Fungal Trees of Life project at the Royal Botanic Gardens, Kew. We present the first findings of this study, which will contribute to understanding intergeneric relationships and form a basis to enable researchers to investigate many questions across the subfamily on ecology, patterns of diversification, genome duplication, nodulation and character evolution that might help to explain its global success.

## S.64.2 Advances in papilionoid systematics: insights from the Dalbergioid clade (from rosewoods to fodder plants and peanuts)

Ana Paula Fortuna Pérez¹, Bente Klitgård²

1 Universidade Estadual Paulista, Botucatu, São Paulo, Brazil.
2 Royal Botanic Gardens, Kew, UK.

Dalbergioid legumes form a mostly pantropical clade containing 46 genera and about 1,370 species, of which more than half belong in four big genera: Adesmia, Aeschynomene, Dalbergia, and Machaerium. The Dalbergioid legumes encompass three lineages composed of the Adesmia, Pterocarpus and Dalbergia clades. The Amor-
<figure><img src="image_161.png" /></figure>

pheae clade, resolved as sister to the Dalbergi-
oid clade, includes eight genera of shrubs usu-
ally with paripinnate leaves, and predominantly
North American. The genera form two subclades,
the Daleoids and the Amorphoids. The Amorphe-
ae clade is characterised by loss of the papilion-
aceous flower several times in its evolutionary
history, especially in the Amorphoid subclade.
This loss also occurs within the Dalbergioid clade,
specially within the Pterocarpus clade. Additional
to the genus *Acosmium* (moved to the Pterocar-
pus clade), the newly described *Maraniona*, and
the reestablishment of the genera *Steinbachiella*
and *Ctenodon*, recent systematic studies on Dal-
bergioid legumes have elucidated infrageneric
relationships in the genera *Aeschynomene* (now
excluding *Ctenodon*), *Dalbergia*, *Pterocarpus*, *Ade-
smia*, *Nissolia* (now encompassing *Chaetocalyx*),
*Zornia* and *Stylosanthes*. Studies on floral ontoge-
ny in the Dalbergioid clade have highlighted inter-
esting data. In species of the Adesmia clade gen-
era, variations are observed in the papilionaceous
flowers where suppressions, abortions, reduction
and/or acquisition of floral parts occur. And oth-
er phylogenomic, anatomical and morphological
studies are increasing our understanding of many
new traits in the Dalbergioid clade. Belonging to
Dalbergioid legumes are a wide range of eco-
nomically important species and their crop wild
relatives, the best known being *Arachis hypogea*
L. (peanut), *Dalbergia* spp. (rosewoods), and *Sty-
losanthes* spp. (forage). However, additional gen-
era include tree species with sought after timber.
Ensuring that evolutionary relationships and tax-
onomy are well-understood, provide prerequisites
for conservation actions for threatened tree spe-
cies; and thus, gives plant systematists an even
more important role to play.

### S.64.3 Revisiting Ebenus L. (Leguminosae): a molecular perspective

Ozan Şentürk¹, Zeki Aytaç², Gregory J. Kenicer¹

1 Royal Botanic Garden Edinburgh, Edinburgh, UK. 2 Faculty of Science, Gazi University, Ankara, Türkiye

The genus *Ebenus* L. (Leguminosae, Papilionoideae, Tribe Hedysareae) consists of 21 perennial shrubs and subshrubs with high levels of country and regional endemism. It is known from the

Arabian Peninsula only in Oman, through the
Irano-Turanian region, with a centre of species
diversity in Türkiye (14 species) and around the
Eastern Mediterranean through North Africa as
far as Morocco. As such, its distribution offers a
prospective model for understanding aspects of
East-West Mediterranean biogeography. The ge-
nus was revised by Huber-Morath in 1964 with a
focus on groups from Anatolian Türkiye but the
taxonomy and biogeography of the genus have
never been investigated as a whole. This talk
presents the results of the first genomic study of
the genus, and indeed the first comprehensive
phylogenetic study of the genus. We generated
sequence data for between one and five speci-
mens of each of the 21 recognised species, plus
four outgroups from other genera in the tribe
Hedysareae. These data were assessed using
Bayesian and ML analyses to produce a compre-
hensive phylogeny for the group. The purpose of
this presentation is to introduce and discuss the
results of these phylogenetic analyses in taxo-
nomic and biogeographical contexts. Particular
attention is paid to the relationships between Ira-
no-Turanian and Mediterranean floristic regions,
ecoregions and habitat preferences. In addition,
morphological patterns such as spinescence,
corolla, colour, leaflet pairs, and peduncle are in-
terpreted in the light of the phylogeny.

### S.64.4 Towards a comprehensive phylogeny of the largest flowering plant genus: a herbarium-based study of Astragalus (Fabaceae)

Daniele Buono¹, Diego F. Morales-Briones
¹, Shahin Zarre², Aaron Liston³, Gudrun Kadereit¹

1 Ludwig-Maximilians-Universität München, Munich, Germany. 2 University of Tehran, Tehran, Iran. 3 Oregon State University, Corvallis, USA

Astragalus (Fabaceae, Papilionoideae), with
about 3,000 species, is considered the largest
genus of flowering plants and represents a strik-
ing example of recent rapid radiation. Our under-
standing of the evolutionary drivers and adaptive
traits responsible for this mega-radiation is frag-
mentary due to insufficient sampling and poorly
resolved phylogenetic trees. It has been suggested that edaphic specialisation and colonisation of extreme microhabitats led to the divergence of lineages in *Astragalus*. To assess the evolutionary radiation and its drivers in *Astragalus*, we are using a target enrichment approach to obtain a robust phylogeny. We designed a large bait set based on 686 orthologous genes (819 exons) specific for the Astragalean clade, which can potentially resolve complex relationships in *Astragalus*. Our sampling is focused on main centres of diversity (Iran, Turkey, and Afghanistan) and relies on the rich *Astragalus* collection at the Botanical State Collection Munich (BSM-SNSB - about 25,000 *Astragalus* specimens from all around the world). We constructed a preliminary phylogeny including representatives of major sections based on 101 species (85 *Astragalus* plus 13 Astragalean clade species and three outgroups). A well-supported phylogeny at the subgenus level was recovered, mainly in agreement with previous phylogenies. Yet, several differences between previous phylogenies and the current sections were recognised, and clear signals of discor-dance along the backbone were found. We also established a fast and reliable workflow for digitising the *Astragalus* herbarium collection at SNSB. Using manual and automated machine learning techniques allows us to extract morphological traits from specimens and voucher data from labels. Mined data, such as geographic origin and habitat description, can complement genomic data and allow for various studies (e.g., niche modelling, evolution of morphological traits, and much more) to be performed on the extensive herbarium collection, gaining more insights into the drivers of diversification in *Astragalus*.

**S.64.5 Progress in systematic studies in the Adesmia clade (Leguminosae: Papilionoideae: Dalbergieae)**

Thiago Cobra e Monteiro¹, Higor Antonio-Domingues², João R.V. Iganci³, Renan P. Campos¹, Gwilym P. Lewis², Mohammad Vatanparast², Bente Klitgård², Federico Luebert⁴, Flávia Pezzini⁵, Rafaela J. Trad⁵, Marcus Falcão⁶, Vidal F. Mansano⁶, Carolina M. Siniscalchi⁷, Ryan Folk⁷, Silvia T. S. Miotto⁸, Cynthia F. P. da Luz⁹, Mônica L. Rossi¹⁰, Rafael F. de Almeida², Adriana Pinheiro-Martinelli¹⁰, Ana Paula Fortuna Pérez¹

1 Universidade Estadual Paulista, Botucatu, São Paulo, Brazil. 2 Royal Botanic Gardens, Kew, UK. 3 Universidade Federal de Pelotas, Rio Grande do Sul, Brazil. 4 Universidad de Chile, Santiago, Chile. 5 Royal Botanic Garden Edinburgh, UK. 6 Instituto de Pesquisas do Jardim Botânico do Rio de Janeiro, Brazil. 7 Mississippi State University, United States of America. 8 Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. 9 Instituto de Pesquisas Ambientais, São Paulo, Brazil. 10 Universidade de São Paulo, Esalq, Piracicaba, Brazil

The Adesmia clade encompasses five genera: Adesmia, Amicia, Nissolia, Poiretia and Zornia, and it is sister to the Pterocarpus and Dalbergia clades (Dalbergieae). The clade arose ca. 35 Ma ago, and all genera are monophyletic, but the infrageneric divisions of the two largest genera (Adesmia and Zornia) are paraphyletic. Adesmia is the largest genus of the clade with over 200 species almost exclusively distributed along the western South American Dry Diagonal (wSADD), which stretches from Patagonia to the Peruvian Desert and contains some of the driest environments on Earth. While the ancestor of Adesmia is associated with the wSADD, the ancestor of the clade (i.e., Amicia, Poiretia, and Zornia, ca. 100 species) is associated with the eastern South American Dry Diagonal (eSADD). The eSADD comprises the Chaco, Cerado, and Caatinga domains, and is marked by a seasonal precipitation regime. Sister to the other genera within the Adesmia clade, Nissolia has a distinct distribution within Seasonal Dry Tropical
<figure><img src="image_162.png" /></figure>

Forests. Both vegetative and reproductive characters exclusive to this clade may have impacted the group diversification in the dry diagonals of South America. There are several potential functional traits linked to the occupation, diversification, and maintenance of Adesmia clade species in dry environments. These include a variety of secretory structures, growth forms and life history strategies, underground structures, spinescence, and fruit morphologies, e.g., the evolution of samaroid fruits in Nissolia, shared with other genera in Dalbergieae, suggesting that they may be ancestral to the typical lomentaceous fruit characteristic of the other four genera. Studies of pollen morphology and floral ontogeny bring an important contribution to understand the evolution of the clade and are discussed. Disk-shaped nectary was found in flowers of Adesmia and Nissolia, which have not been previously reported for the clade and may be a morphological character of taxonomic value.

## S.64.4 A phylogenetic insight into Astragalus diversification and biogeography

Carolina M. Siniscalchi¹, Joseph L.M. Charbonneau², Michael B. Belitz³, Aliasghar A. Maassoumi⁴, Tajinder Singh⁵, Heather R. Kates³, Douglas E. Soltis³, Pamela S. Soltis³, Robert P. Guralnick³, Ryan A. Folk⁵

1 General Libraries, Mississippi State University, Mississippi State, USA. 2 Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, USA. 3 Florida Museum, University of Florida, Gainesville, USA. 4 Research Institute of Forests and Rangelands, Tehran, Iran. 5 Department of Biological Sciences, Mississippi State University, Mississippi State, USA

Astragalus (Fabaceae) represents a remarkable successful radiation of highly similar species in temperate, cold arid regions of Earth. The factors behind its extraordinary diversity have attracted attention from systematists and biogeographers, especially on what sets it apart from less species-rich relatives. Yet its status as the iconic plant megagenus has both highlighted and hindered study of this fascinating diversity. Here, using phylogenomics and an extensive sampling, we ask if Astragalus diversification is uniform or

characterized by radiation bursts. We additionally test whether the species diversity of *Astragalus* is attributable specifically to its predilection for cold and arid habitats, types of soils, or if it is influenced by chromosome evolution. Finally, we test whether *Astragalus* originated in central Asia as proposed and whether niche evolutionary shifts were subsequently associated with the colonization of other continents. Our results show the importance of heterogeneity in the diversification of *Astragalus*, with upshifts associated with the earliest divergences but not strongly tied to any of the tested abiotic factor or biogeographic regionalization. Chromosome number was the only factor potentially correlated with diversification. In contrast to diversification shifts, biogeographic shifts have a strong association with the abiotic environment and highlight the importance of central Asia as a biogeographic gateway. Our investigation shows the importance of phylogenetic and evolutionary studies of logistically challenging “mega-radiations.” Our findings reject any simple key innovation behind high diversity and underline the often nuanced, multifactorial processes leading to species-rich clades.
# S.65 PLANT CONSERVATION IN MEDITERRANEAN AND MACARONESIAN ISLANDS. SESSION 1

## S.65.1 Wetland plants in Mediterranean Islands: a checklist of globally or regionally threatened species

Mauro Fois¹, Alba Cuena², Gianluigi Bacchetta¹, Simonetta Bagella², Giulio Barone³,⁴, Leanne Camilleri⁵, Katia Debono⁵, Giannantonio Domina³, Sandro Lanfranco⁵, Maria Panitsa⁶, Salvatore Pasta⁷, Angelo Troia⁸, Lorenzo Lazzaro⁹, Pere Fraga-Arguimbau¹⁰, Richard V. Lansdown¹¹, Ioannis Bazos¹², Pietro Minissale¹³, Toni Nikolic¹⁴, Charalambos S. Christodoulou¹⁵, Costas Kadis¹⁶, Imtinen Ben Haj Jilani¹⁷,¹⁸, Amina Daoud-Bouattour¹⁸, Serge D. Muller¹⁹, Adriano Stinca²⁰, Christini Fournaraki²¹, Miquel Capó²², Antoine Gazaix²³, Necmi Aksoy²⁴, Katia Diadema²⁵

1 University of Cagliari, Department of Life and Environmental Sciences, Cagliari, Italy. 2 University of Sassari, Department of Chemical, Physical, Mathematical and Natural Sciences. 3 University of Palermo, Department of Agricultural, Food and Forest Sciences, Palermo, Italy. 4 NBFC, National Biodiversity Future Center, Palermo, Italy. 5 University of Malta, Department of Biology, Msida, Malta. 6 University of Patras, Department of Biology, Patras, Greece. 7 Institute of Biosciences and BioResources, National Research Council, Palermo, Italy. 8 University of Palermo, Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), Palermo, Italy. 9 University of Florence, Department of Biology, Florence, Italy. 10 Jardí Botànic Marimurtra, Fundació Privada Carl Faust, Blanes, Girona, Spain. 11 IUCN SSC Freshwater Plant Specialist Group, Gloucestershire, UK. 12 National and Kapodistrian University of Athens, Department of Biology, Panepistimiopolis, Athens, Greece. 13 University of Catania, Department of Biological, Geological and Environmental Sciences, Catania, Italy. 14 University of Zagreb, Department of Biology, Zagreb, Croatia. 15 Ministry of Agriculture, Rural Development and

Environment, Lefkosia, Cyprus. 16 Frederick University, Nature Conservation Unit, Nicosia, Cyprus. 17 Université de Carthage, Institut National Agronomique de Tunisie, Tunis, Tunisie. 18 Université de la Manouba, Biogéographie, Climatologie appliquée et Dynamiques environnementales, Manouba, Tunisie. 19 Université de Montpellier, CNRS, IRD, EPHE, Institut des Sciences de l'Évolution, Montpellier, France. 20 Université of Campania Luigi Vanvitelli, Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Caserta, Italy. 21 Mediterranean Plant Conservation Unit of Mediterranean Agronomic Institute of Chania (CIHEAM-MAICH), Crete, Greece. 22 Universidad Politécnica de Madrid, Centro para la Conservación de la Biodiversidad y el Desarrollo Sostenible, Madrid, Spain. 23 Tour du Valat, Institut de recherche pour la conservation des zones humides méditerranéennes, Arles, France. 24 Duzce University, Department of Forest Botany & DUOF Herbarium, Duzce, Türkiye. 25 Conservatoire botanique national méditerranéen de Porquerolles, Hyères, France.

In the Mediterranean Basin, the conservation of plants faces critical challenges due to the historic and ongoing impacts of human land use, placing biodiversity under pressure. This issue is particularly pronounced on islands, where the intrinsic fragmentation of freshwater environments is exacerbated by the limited land area. Consequently, island wetlands, which are generally smaller than their continental counterparts, are more fragile and often overlooked in conservation efforts. Therefore, addressing the need for improved knowledge of wetland plants occurring on islands is a crucial objective that remains largely unresolved. Challenges persist, including cryptic taxonomy within certain genera, and there is still a need for a comprehensive overview of the diversity, distribution, and conservation status of these plants. These knowledge gaps contribute to policy and management shortcomings, hindering effective conservation or recovery efforts. This study seeks to bridge these knowledge gaps by compiling information from local experts on wetland vascular plants occurring on the approximately 10,000 Mediterranean islands and islets. Our work presents and discusses the preliminary results of a checklist of over 200 wetland vascular plants of conservation interest. Remarkably, 20% of these species are globally endangered, 50%
<figure><img src="image_163.png" /></figure>

face threats on at least one island, and available information is inadequate to assess the conservation status of 30%. The insights provided in this study can support parallel initiatives, such as the Red List Index of Mediterranean wetland plants. Moreover, they can serve as a reference for planning targeted conservation actions and fostering public awareness about plant diversity in Mediterranean island wetlands.

## S.65.2 Importance of small islands of the Mediterranean and Macaronesian regions as refugia of plant biodiversity

Frédéric Médail¹

1 Aix Marseille University, Mediterranean Institute of Biodiversity and Ecology, Aix-en-Provence, France. frederic.medail@imbe.fr

This study aims to show the importance of small islands and islets (ie territories < 1000 ha) of the Mediterranean Basin hotspot, including those of the Mediterranean and Macaronesian biogeographic regions, from the point of view of their plant biodiversity and their role in the conservation of coastal ecosystems.

In the Mediterranean region, there are numerous islands (> 11,000) including a high diversity in term of plant species and of ecosystems' types. These patterns can be explained by complex interactions between a highly heterogeneous historical biogeography and ecological processes. Furthermore, most of the ups and downs of this biodiversity were closely linked with human pressures which have changed many times through the long socio-ecological history of these island landscapes since the Neolithic period. In the Macaronesian region, small islands and islets (named PIMAs, by Médail et al., in prep.) are less numerous (n = 430). Islets with a surface area of less than 1 ha are predominant (88% of the whole PIMAs, i.e.,377 islets), and only 20 islands possess an area comprised between 11 and 1000 ha. These oceanic small islands are characterized by an exceptionally high richness of endemic taxa and constitute outstanding refugia for rare and threatened plant species. These PIMAs are nevertheless impacted by a diversity of human-related threats, notably the presence of invasive alien species, tourist pressure, or overgrazing. The level of knowledge of biodi-

versity is heterogeneous between the archipelagos and PIMAs are often neglected in conservation policies. If small islands and islets of the Mediterranean and Macaronesian regions have been neglected for a long period, current researches point out their disproportionate role to preserve coastal biodiversity (from genes to landscape). With regards to the biome crisis, they constitute key ecological systems and 'current refugia' to ensure the long-term preservation of this highly threatened biodiversity.

## S.65.3 Exploring plant traits that indicate vulnerability among the endemic flora of the Balearic Islands

Joana Cursach¹, Miquel Capó², Theodora Petanidou³ and Amparo Lázaro⁴,⁵

¹ Research Group on Plant Biology under Mediterranean Conditions, Department of Biology, University of Balearic Islands, Palma, Spain. ² Plant & Animal Ecology Lab. Centro para la Conservación de la Biodiversidad y el Desarrollo Sostenible, Departamento de Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, Madrid, Spain. ³ Laboratory of Biogeography & Ecology, University of the Aegean, Mitilene, Greece. ⁴ Global Change Research Group, Mediterranean Institute for Advanced Studies (UIB-CSIC), Esporles, Spain. ⁵ Area of Ecology, Department of Biology, University of Balearic Islands, Palma, Spain

The threat categories proposed by IUCN are mostly based on trends in population sizes and geographical range estimates. However, other factors could also be predictors of plant vulnerability, such as those related to the architectural complexity of flowers (e.g. floral shape and symmetry), or plant reproduction (e.g. flowering duration, life form, capability of asexual reproduction). Here, we analysed plant traits that could be potential predictors of vulnerability focusing on the endemic flora of the Balearic Islands, a hotspot of biodiversity and endemicity within the Mediterranean Basin. For this, we compiled the list of entomophilous plant species endemic to the Balearic Islands, categorized their vulnerability according to the regional Red Data Book, and gathered bibliographic data about both intrinsic and extrinsic factors that could affect plant vulnerability. We selected 10 intrinsic factors (floral shape, floral tube length,
floral symmetry, corolla segmentation, floral size, floral colour, flowering season, flowering duration, life form and the capability of sexual reproduction) and one extrinsic factor (main habitat). The endemic entomophilous flora of the Balearic Islands comprises 156 taxa, 57 of which (37%) are threatened (EW, CR, EN and VU). We used Generalized Linear Models to test the potential effects of both intrinsic and extrinsic factors on plant vulnerability using a binomial response variable with two categories: "threatened" (EW, CR, EN, VU) and "not threatened" (NT, LC), and obtained optimal models based on the Akaike Information Criterion to select the best predictors for plant vulnerability. Our results showed that flowering duration and habitat were main predictors of vulnerability in the endemic flora of the Balearic Islands. Plants with short flowering duration, and freshwater, littoral and mountain plants were those more threatened. This study emphasizes the importance of studying other useful traits as indicators of species extinction risk in order to enhance plant conservation.

## S.65.4 Can we predict the response of Canarian plant communities to increasingly dry conditions through leaf physiological traits?

Jaime Puértolas¹*, Águeda M. González-Rodríguez¹, Alicia Perera-Castro¹, Yauci Espinosa-González¹, Celine I. García-Rodríguez¹, Beatriz Fernández-Marín²

1 Department of Botany, Ecology, and Plant Physiology, Universidad de La Laguna, La Laguna, Spain. 2 Department of Plant Biology and Ecology, Universidad del País Vasco, Leioa, Spain. * jpuertol@ull.edu.es

Precipitation reduction and increasing temperatures are impacting plant communities of the Macaronesian region. Hence, tools for evaluation and classification of plant species according to their vulnerability to increasing air and soil dryness are needed for plant conservation. Ecophysiological studies focused on a single or small group of species provide important information for this goal, but studies on adaptive ecophysiological trait syndromes could quantitative and qualitative improve our capacity to classify

species according to their drought resistance. In this study, we measured physiological leaf traits related to drought resistance in more than 70 vascular species distributed across the four National Parks in the Canary Islands. The biomes represented in these NPs comprises a very strong climatic gradient within the generally Mediterranean-type climate, especially in terms of water availability, from the arid climate of Timanfaya to the cloud forests of Garajonay, and from the typical Mediterranean climate of the pine forest in Caldera de Taburiente to the alpine dry environment of Mount Teide and the summits of La Caldera de Taburiente. Leaf traits comprised both drought tolerance (leaf rehydration capacity after dehydration, leaf functionality after dehydration, water potential at full turgor) and avoidance traits (leaf hydraulic conductance, minimal leaf conductance, vein and stomatal density, leaf water absorption capacity and hydrophobicity). In addition, climatic data from the last 20 years recorded by the large weather station network located within the four NPs was compiled to calculate drought indices. Trait average values per species was related to climatic data with multivariate statistical tools aimed to establish groups of species and traits and establish relationships with climatic aridity. The results allowed identifying different trait combinations (syndromes) and their variation along the climatic aridity gradient. We classified the studied species based on those syndromes, thus defining strategies and overall predicted capacity to resist drought.

## S.65.5 Plant conservation in the Aegean Archipelago - knowledge building and conservation initiatives

Maria Panitsa¹, Christini Fournaraki², Katerina Koutsovoulou³, Konstantinos Kougioumoutzis¹, Michalis Choreftakis², Costas A. Thanos³

1 University of Patras, Patras, Greece. 2 CIHEAM - Mediterranean Agronomic Institute of Chania (MAICh), Chania, Greece. 3 National and Kapodistrian University of Athens, Athens, Greece

The Aegean Archipelago is comprised of 123 inhabited islands (Crete, Euboea, Lesbos, Rhodes etc.) and more than 8,000 uninhabited ones. It is divided into 5 floristic regions, with the East Aegean and Crete-Kar-
<figure><img src="image_164.png" /></figure>

pathos (KK) ones hosting the richest total floras while KK, Kiklades and West Aegean are richest in endemics. In total, 740 endemic taxa grow in the Aegean of which 62% are regional and 42.4% are Single Island endemics. The first round of conservation status assessments (by HBS in collaboration with IUCN) will conclude by the end of 2023 and a rough estimate of 50% of the endemics seem to be categorised as threatened (CR, EN, VU), most of them facing high extinction risk, uplifting the in situ and ex situ conservation of these plants to an urgent national target. It is noteworthy that ten out of the TOP50 critically endangered Mediterranean plant taxa, and 44% of the plant taxa of Annexes II, IV & V of the Directive 92/43/EEC are found in the Aegean. The Aegean Archipelago also hosts 38% of the Greek NATURA2000 sites, governed by 7 Management Units of Protected Areas; currently, in situ conservation measures for protected or endangered plants are taken mainly within these protected areas. In addition, Plant Micro-Reserves have been established for 7 taxa and one habitat type in Crete while 5 new ones are about to be established in Rhodes, Karpathos and Kastellorizo. Ex situ conservation actions include numerous taxa stored in Seed Banks along with compiling germination protocols and developing plans for in situ population reinforcements. This work, apart from presenting the progress made during the last decades in knowledge building and conservation initiatives, aims to reveal and prioritise the gaps of plant conservation in the Aegean Archipelago.

## S.65.6 Ecological forecasting for Aegean endemics: modeling the future of cliff-dwelling plant species

Konstantinos Kougioumoutzis¹, Anna Kontopanou¹, Ioannis P. Kokkoris¹, Arne Strid², Panayotis Dimopoulos¹, Maria Panitsa¹

1 Laboratory of Botany, Department of Biology, University of Patras, Patras, Greece, 2 Bakkevej 6, Ørbæk, Denmark

The Aegean archipelago, the world's second largest, lies at the crossroads of Europe, Africa, and Asia. This unique ecological laboratory comprises approximately 8,000 islands and islets, hosting around 600 endemic species. Among these, certain chasmophytes are confined to calcareous,

inaccessible cliffs, a consequence of historical paleogeographical events and ongoing biogeographical processes. These chasmophytes exhibit limited competitive and dispersal capacities, primarily due to the large size of their diaspores and highly specialized niches. Having endured harsh environmental conditions for millennia, these species now confront an unprecedented threat level due to the synergistic impacts of climate change and land-use modifications. This study investigates the potential effects of future climate and land-use changes on the distribution patterns of these endemic cliff-dwelling species. Utilizing a species distribution modeling framework, we assess these impacts across three time periods and propose conservation strategies to mitigate their potential decline.
# S.66 NEW FRONTIERS IN PLANT PHYLOGENOMICS. SESSION 4

## S.66.1 Genomic incongruence accompanies the evolution of flower symmetry in Eudicots: a case study in the poppy family (Papaveraceae)

Lisa Pokorny¹,³, Jaume Pellicer²,³, Yannick Woudstra³,⁴, Maarten J. M. Christenhusz³,⁵, Teresa Garnatje²,⁶, Luis Palazzesi⁷, Matthew G. Johnson⁸, Olivier Maurin³, Elaine Françoso³, Shyamali Roy³, Ilia J. Leitch³, Félix Forest³, William J. Baker³, Oriane Hidalgo²,³

¹Real Jardín Botánico (CSIC), Madrid, Spain. ²Institut Botànic de Barcelona, CSIC-Ajuntament de Barcelona, Barcelona, Spain. ³Royal Botanic Gardens, Kew, Richmond, UK. ⁴Natural History Museum of Denmark, Copenhagen, Denmark. ⁵Curtin University, Perth, Australia. ⁶Jardí Botànic Marimurtra - Fundació Carl Faust, Blanes, Spain. ⁷Museo Argentino de Ciencias Naturales, CONICET, Buenos Aires, Argentina. ⁸Texas Tech University, Lubbock (TX), USA

Reconstructing evolutionary trajectories and transitions that have shaped floral diversity relies heavily on the phylogenetic framework on which traits are modelled. In this study, we focus on the angiosperm order Ranunculales, sister to all other eudicots, to unravel higher-level relationships, especially those tied to evolutionary transitions in flower symmetry within the family Papaveraceae. This family presents an astonishing array of floral diversity, with actinomorphic, disymmetric (two perpendicular axes of symmetry), and zygomorphic flowers. We generated nuclear and plastid datasets using the Angiosperms353 universal probe set for target capture sequencing (of 353 single-copy nuclear ortholog genes), together with publicly available transcriptome and plastome data mined from open access online repositories. We relied on the fossil record of the order Ranunculales to date our phylogenies and

to establish a timeline of events. Our phylogenomic workflow shows that nuclear-plastid incongruence accompanies topological uncertainties in Ranunculales. A cocktail of incomplete lineage sorting, post-hybridization introgression, and extinction following rapid speciation most likely explain the observed knots in the topology. These knots coincide with major floral symmetry transitions and thus obscure the order of evolutionary events.

## S.66.2 Complete chloroplast genome sequence and phylogenetic relationships of some Acanthoideae species (Acanthaceae)

Samaila S. Yaradua¹

¹Department of Geography, Environmental Management and Energy Studies, University of Johannesburg, Johannesburg, South Africa

The plastid genomes of Acanthoidea were sequenced and compared with plastome of other sequenced Acanthoideae species to characterize the plastomes, identify the simple sequence repeats (SSRs), detect variations among the cp genomes and to infer their phylogenetic relationships. The plastome was assembled from the whole genome sequences using NOVOPlasty. The cp genomes of the species ranged from 149, 717 bp to 152,217 bp in length with GC and AT contents of 38.3 and 61.7 % respectively and have a quadripartite and circular structure, the genome constitutes of a pair of inverted repeats (IRa and IRb) which are separated by large single copy (LSC) and small single copy (SSC). A total of 131 genes were identified in the genomes, comprising of 80 protein-coding genes, 30 tRNA and 4 rRNA; 113 are unique, 18 were duplicated in IR regions. The analysis of long repeat showed all types of repeats were present in the plastomes and palindromic has the highest frequency. A total number of 98 SSR were also identified in the cp genome of *B. prionitis* and *J. flava* of which majori-
ty were mononucleotide A/T. Genome comparative analysis among the plastomes revealed that the IRs regions are more conserved than large single copy and small single copy. In addition, high variation is observed in the noncoding region than the coding. The genes, *ndhF* and *ycf1* are located at the border junction of the small single copy region and IRb region of all the plastome. The sequence divergence analysis indicates that the following genes undergo positive selection (*atpF*, *petD*, *psbZ*, *rpl20*, *petB*, *rpl16*, *rps16*, *rpoC*, *rps7*, *rpl32* and *ycf3*). Phylogenetic analysis indicated sister relationship between Ruellieae and Justcieae. In addition, *Barleria*, *Justicia* and *Ruellia* are paraphyletic, suggesting that Justiceae, Ruellieae, Andrographideae and Barlerieae should be treated as tribes.

### S.66.3 Whole genome sequencing deciphering nonbifurcating diversification of Camellia (Theaceae)

Qiong Zhang¹, Ryan A. Folk², Jian-Li Zhao³, Shi-Xiong Yang¹, Xiang-Qin Yu¹,*

1 CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
2 Department of Biological Sciences, Mississippi State University, MS, United States. 3 Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology and Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming, China. * yuxiangqin@mail.kib.ac.cn

Although increasing evidence suggested that introgression and reticulation might have affected almost all parts of the tree of life, published examples likely represent the tip of the iceberg in terms of the total extent of the ancient hybridization. *Camellia*, the largest genus with significant economic value of Theaceae, has controversial taxonomy and systematics due in part to a complex evolutionary history. Here, we sampled 64 species representing 20 out of 22 sections of *Camellia* according to Chang's system. Integrating a group of data sets such as single copy nuclear genes, single-nucleotide polymorphism (SNP) and plastid coding genes extracted from whole genome resequencing data to investigate the patterns of reticulate evolution of *Camellia*. *Camellia* was divided into eight major clades (C1-C8). Our results yielded much phylogenetic incon

gruence among topologies reconstructed by three datasets (single copy nuclear genes, SNP, plastid genes) based on different methods (concatenation and coalescent), especially the cyto-nuclear discordance was observed. But all of them support non-monophyletic of sections proposed based on morphological characters. The splits phylogenetic network reconstructed by 508 single copy nuclear genes and ABBA-BABA test conducted by SNP data all support the introgression events in *Camellia*. Four groups based on the minimum CV error value were recovered in Admixture analysis, hybridization events are concentrated on Group II (C2-C6) and Group IV (C8). Although hybridization/introgression have some impacts on the reconstruction of the phylogenetic relationships of *Camellia*, no consistent topologies were detected after removing the putative introgressed loci in SNP. Our study laid a foundation for future researches of *Camellia*, such as plant taxonomy, evolutionary genomics, population genomics, and also provided a theoretical basis for the utilization and protection of important wild plant germplasm resources of the family.

### S.66.4 Diversification history of Pedicularis (Orobanchaceae) in the Himalaya-Hengduan Mountains Region

Rong Liu¹,², Wen-Bin Yu³,⁴, Hong Wang¹,², De-Zhu Li²,¹

1 Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China. 2 Plant Germplasm and Genomics Centre, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China. 3 Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China. 4 Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, Yunnan, China

The c. 270 species of *Pedicularis* endemic to the Himalaya-Hengduan Mountains (HHM) region exhibits considerable diversity in geographic distribution, elevational range, and floral morphology. Many of the species, including those with the longest corolla tubes and beaked galeas, fall within a single clade, implying putative *in situ* radiations. We conduct phylogenetic analyses of a clade (informally named
<figure><img src="image_165.png" /></figure>

"Clade 3" in our previous work) concentrated in the HHM to infer drivers of diversification and the biogeographic history. Integrating plastome phylogeny, environment data and species distribution data, we revealed the species diversity pattern and identified the key environmental factors of *Pedicularis* Clade 3. Subsequently, we estimated the macroevolutionary rate and reconstructed ancestral distribution and corolla traits. Meanwhile, we evaluated the correlation between distribution overlap and phylogenetic distance. Our results suggest that Northwestern Yuan-nan-Kangding within the HHM region is the center of species diversity of *Pedicularis* Clade 3 and this pattern is constrained by precipitation and multiple environmental factors; Parallel range expansion from the Sanjiang valley and subsequent allopatric speciation across the HHM are the dominant process in early rapid diversification and may be a major contributor to the high species accumulation of *Pedicularis* spp. Additionally, the evolution of corolla is not associated with the speciation, but as a response of species richness. Our study highlights the importance of integrated evidence for understanding species diversification pattern, and this pattern may be applicable to explain the diversity of other hyper-diverse alpine genera in the HHM region.

## S.66.5 Advancing our understanding of oak evolution in the genomic era

Drew A. Larson¹, Margaret Staton², C.

Dana Nelson³, Andrew L. Hipp⁴, Matthew

W. Hahn¹

1 Indiana University, Bloomington IN, USA. 2 University of Tennessee, Knoxville TN, USA. 3 USDA Forest Service Southern Research Station, Lexington KY, USA. 4 Morton Arboretum, Lisle IL, USA

Advances in sequencing and analytical technologies have dramatically changed the field of plant phylogenetics and the ever-increasing availability of high-quality reference genomes now offers a particular opportunity to further reveal the evolutionary history of plant clades. We utilized a new haplotype-resolved reference genome for *Quercus alba* and whole genome resequencing to investigate the history of speciation and introgression in oaks, with a particular focus on North American white oaks. We show that phylogenetic results using a whole genome dataset disagree with previously published relationships among oak species and find wide-

spread phylogenetic conflict across the genome. We further show that a high proportion of polymorphisms are shared across multiple species, which has important implications for time-calibrating the phylogeny of oaks and other species that maintain large population sizes. We investigated introgression among oaks species and identify specific genomic regions showing notable signals of introgression, suggesting that introgression could potentially facilitate adaptive evolution among North American white oak species. As the sequencing and assembly of reference quality genomes becomes ever more routine, whole genome phylogenomic analyses such as these will likely become increasingly relevant and useful to the botanical community.

## S.66.6 Cryptic speciation among polyploid mosses demonstrated through phylogenomic analysis

Nikisha Patel¹,², Matt Johnson³, Rafael

Medina⁴, Bernard Goffinet²

1 Biology Department, Trinity College, Hartford, Connecticut, USA. 2 Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA. 3 Department of Biology, Texas Tech University, Lubbock, Texas, USA. 4 Departamento de Biodiversidad, Ecología y Evolución, Universidad Complutense, Madrid, Spain

Whole genome duplication (WGD) is a mechanism critical to evolutionary change and speciation across the plant tree of life. Both conspecific genome doubling (autopolyploidy) and WGD following hybridization (allopolyploidy) may result in morphologically distinct lineages and hence may contribute significantly to species diversity. However, accumulate phylogenetic reconstruction of allopolyploids and their component genomes remains a major challenge. The moss *Physcomitrium pyriforme* is a widespread species complex found across North America and Europe that exhibits substantial morphological variation, evident in the recognition of 29 synonyms. We hypothesize that this species complex comprises not only numerous cytotypes and potential species from repeated WGD events, but also population structure among haploid populations that will inform the evolutionary history of allopolyploids and autopolyploids. We sampled over 400 populations of *P. pyriforme* across its North American and use a target capture approach to sequence 648 genes to construct a phylogenetic
tree establishing relationships among *P. pyriforme* populations. 60 allopolyploid populations are identified using HybPhaser suggesting that WGD plays a substantial role in the evolution of the *P. pyriforme* complex. Further, structure analysis of haploid populations of *P. pyriforme* offers insights into gene flow and introgression further elucidating the nature of

reticulation among haploid, autopolyploid, and allo-
polyploid populations. These analyses both provide
evidence for morphologically cryptic speciation via
polyploidy and also provides evidence for the utility
of target capture sequencing with an 806 gene bait
set for population genomic studies and population
demographic inferences.

**S.67 TOWARDS A MORE ETHICAL SCIENCE:**
**DECOLONIZING BOTANICAL RESEARCH.**
**SESSION 2**

S.67.1 Decolonising
biodiversity collections:
equity, collaboration, and
benefits

Quentin Groom, Sofie Meeus¹

1 Meise Botanic Garden, Meise, Belgium

In response to historical inequalities, museums are
engaging in the decolonization of biodiversity col-
lections. This entails acknowledging collection histo-
ries, enhancing accessibility, and promoting collab-
orative research. Despite this effort, decolonization
remains contentious due to unequal access, bi-
opiracy concerns, and "parachute science" where
Global North researchers extract specimens from
the Global South without considering local con-
cerns. Internationally the Nagoya Protocol aims to
ensure fair benefit sharing, yet scepticism persists.
We used a data-driven approach to understand the
interplay between research, biological collection,
and international collaboration. Focusing on Mont-
serrat and the Cayman Islands, the study analyses
collector profiles, their publications, and using data
mediated by the Global Biodiversity Information Fa-
cility and Wikidata. By using a data driven approach
we try to quantify some of the less tangible benefits
of biological collection and provide objective infor-
mation on this issue. Our results reveal specimens
from these islands are held predominantly in the
USA, Canada, and the UK. Most of the research con-
ducted is related to taxonomy. However, digitization
gaps may skew findings. The study emphasises the
need for equitable sharing of both monetary and
non-monetary benefits. While researchers gain
knowledge and prestige, territories should benefit

from research outcomes. Open-access publishing,
data sharing, and duplicate contributions to local
collections are suggested to enhance collabora-
tion. This aims to improve relationships, rectify his-
torical disparities, and inform equitable practices.
In conclusion, biodiversity collection decolonization
involves recognizing historical imbalances and pro-
moting inclusive collaboration. The study advocates
for responsible research practices, acknowledging
local expertise, and fostering equitable partnerships.
By delving into collection complexities, the study en-
visions a more equitable future for biodiversity re-
search and conservation.

S.67.2 Pathways to
decolonizing botanical
research by digitizing
biocultural diversity
collections at the New York
Botanical Garden

Kenneth Walker¹, Ina Vandebroek¹,²,
Matthew Pace¹

1 The New York Botanical Garden, Bronx, New York, USA. 2 The University of the West Indies Mona, Faculty of Science and Technology, Department of Life Sciences and Caribbean Centre for Research in Bioscience, Kingston, Jamaica, West Indies

Much can be learned from colonial collections
by decolonizing botanical research. Interdisci-
plinary teams of scholars have recommended a
biocultural framework for the continued curation
of these collections. Recognizing and protecting
biocultural diversity helps to create pathways to-
<figure><img src="image_166.png" /></figure>

**S.68 EVOLUTIONARY ECOLOGY OF PLANTS.**
**SESSION 4**

**S.68.1 Plant adaptations to city life: lessons learnt from dandelions**

Yannick Woudstra¹,²,³, Ron Kraaiveld¹,⁴,
Alger Jorritsma¹, Ernest Rouaud⁵, Timo
van Galen², Kitty Vijverberg², Slavica
Ivanovic¹, Niels C.A.M. Wagemaker⁴,
Roy Erkens⁵, Heidrun Huber⁴, Tanja
Slotte³, Barbara Gravendeel²,⁴, Koen J.F.
Verhoeven¹

1 Netherlands Institute of Ecology, Department of Terrestrial Ecology, Wageningen, The Netherlands.

2 Naturalis Biodiversity Center, Ecology & Evolution Group, Leiden, The Netherlands. 3 Stockholm University, Department of Ecology, Environment and Plant Science, Stockholm, Sweden. 4 Radboud University Nijmegen, Radboud Institute for Biological & Environmental Sciences, Nijmegen, The Netherlands. 5 Maastricht University, Maastricht Science Programme, Maastricht, The Netherlands.

Urbanisation is a globally increasing and highly im-
pactful form of land-use change. Increased tem-
peratures (the urban heat island effect), habitat
fragmentation, light pollution, and other human-in-
duced pressures demand rapid biological adap-
tation from wild species. To discover the necessary
adaptations for surviving urbanisation, we looked at
a thriving urban plant species: the common dan-
delion (Taraxacum officinale F.H.Wigg. s.l.). Along
urban-rural transects, we found urban plants to be
superior in seedling growth at higher temperatures
and flowering response at shorter vernalisation ex-
posure. We also found advancements in flowering
time for suburban genotypes, both in the field and
in controlled environments. These trends were re-
flected in sequence divergence patterns for genes
involved in the regulation of flowering time and heat
resistance, where urban plants displayed high-
ly conserved genotypes. Effects were significantly
different between urban habitats, where city park
plants presented phenotypes intermediate of urban
street and rural field populations. Genetic diversity
among individuals was lowest for street plants and
highest for rural field plants, likely caused by environ-
mental filtering of genotypes in urban environments.

In present-day urban environments, the predicted
effects of climate change are already normalised,
making cities ideal experimental gardens for study-
ing the necessary biological adaptations. Our ap-
proach to study relevant traits in urban plant spe-
cies from both a phenotypic and genomic point of
view is therefore a relevant framework to study the
effects of climate change on plant evolution.

**S.68.2 Running to the hills: changes in plant-pollinator networks structure over time and space, in a mountain region**

Yasmine Antonini¹, Montserrat Arista²,
Fernanda Vieira Costa³, Alejandro Núñez
Cabajal⁴, Juan Arroyo²

1 Departamento de Biodiversidade Evolução e Meio Ambiente, Universidade Federal de Ouro Preto, Ouro Preto - Brazil. 2 Departamento de Biología Vegetal y Ecología, Universidad Sevilla, Sevilla, Spain. 3 Departamento de Ecologia, Universidade de Brasília, Brasília, DF, Brazil. 4 Estación Biológica de Doñana (CSIC), Sevilla, Spain

Pollinator networks play a crucial role in maintain-
ing biodiversity and ecosystem functioning, espe-
cially in mountainous regions. Across an elevation
gradient and flowering seasons, several biotic and
abiotic factors influence community assemblages
of interacting species leading to a shift in species
distribution, functioning, and ultimately topologies
of species interaction networks. In this work, we an-
alyzed the architecture of plant-pollinator networks
by recording plant-insect interactions at 10 study
sites between 1000 and 1800 m a.s.l., following the
two major seasons (from spring to summer flow-
ering seasons) in a Mediterranean mountainous
region. Our research aimed to address the follow-
ing questions: (1) The structure of networks is stable
over time-space? (2) How does the topology of net-
works change over time? (3) Which environmental
drivers shape network structure across time and
space? We analyzed spatial (elevational) and tem-
poral (weeks) network patterns using generalized
<figure><img src="image_167.png" /></figure>

linear models (GLMs) and quantified the influence of climate, richness of flowering plant species, and pollinator diversity on network structures using a multimodel inference framework. We recorded 3,343 interactions, 343 pollinators, and 44 plant species of which a majority involved interactions with bees and flies. We found that nestedness and robustness are constant both in space and time. However, we found that the specialization of plant-pollinator networks increased from spring to summer with the rise of the temperature. Further, network modularity decreases across seasons and plant-pollinator interactions were more specialized at higher elevations. We found that flower and pollinator species diversity and abundance, rather than direct effects of climate, better predict modularity and specialization networks. This study highlights changes in network architectures over time and space (elevation) supporting a potential sensitivity of plant-bee interactions to climate change and desertification, putting Mediterranean mountain biodiversity at risk.

## S.68.3 A tale of species from two clades: evolutionary processes within Corymbia

Susan Rutherford¹,², Alison Paulo Bernardi², Eva Montalban², Justin SH Wan²,³, Maurizio Rossetto²

1 Department of Environmental Science, College of Science, Mathematics and Technology, Wenzhou-Kean University, Wenzhou, China. 2 Research Centre for Ecosystem Resilience, Australian Institute of Botanic Science, Royal Botanic Garden Sydney, Mrs Macquaries Road, Sydney, New South Wales, Australia. 3 School of Environment and Safety Engineering, Jiangsu University, China

Historical processes driving evolution have left a signature in genetic differentiation and gene flow across the landscape of present-day plant populations. Examining these patterns can enable us to better understand lineage divergence. *Corymbia* is a genus within the eucalypts comprising c. 100 species, most of which are endemic to Australia. Recent phylogenetic analyses suggest that *Corymbia* is paraphyletic (with another eucalypt genus *Angophora* nested within *Corymbia*). In the current study, we sampled leaf material from multiple populations of five co-occurring species from across the two paraphyletic clades of *Corymbia* for genome-wide sequencing. We found two species from one clade (*C. maculata* and a more restricted species, *C. eximia*) to be highly genetically differenti-

ated compared to the other species. In contrast, there was evidence of high levels of introgression among two widespread and morphologically similar species from the other clade, *C. gummifera* and *C. intermedia*. To explore the impacts of climatic factors on species evolution, environmental niche models were generated using Maxent to determine the habitat suitability of each species under the Last Glacial Maximum. Overall, our findings offer unique insights into the processes underlying speciation and influencing species boundaries within complex lineages across diverse landscapes.

## S.68.4 Species-soil relationships and their evolution in Amazonian ferns

Hanna Tuomisto¹,², Lassi Suominen², Chi-Chuan Chen², Alfonso Alonso³, Glenda Cárdenas², Samuli Lehtonen², Gabriel Massaine Moulatlet⁴, Eneas Pérez⁵, Anders Sirén²,⁶, Patrick Weigelt⁷, Gabriela Zuquim²

1 Aarhus University, Aarhus, Denmark. 2 University of Turku, Turku, Finland. 3 Smithsonian National Zoo and Conservation Biology Institute, Washington, D.C., USA. 4 University of Arizona, Tucson, USA. 5 Universidad Nacional de la Amazonía Peruana, Iquitos, Perú. 6 Universidad Amawtay Wasi, Quito, Ecuador. 7 University of Göttingen, Göttingen, Germany

Knowledge about plant species niches along environmental gradients is a fundamental prerequisite for addressing many ecological and evolutionary questions. For example, to what degree are plant species distributions and community compositions dictated by species niches in relation to soil properties? And to what degree does evolutionary diversification itself reflect adaptive radiation, where lineages specialize to different edaphic niches? These are especially intriguing questions in the tropical rain forests, where the origin of the high species richness has been a long-standing puzzle, but lack of data has frustrated attempts to find answers. Thanks to long-term extensive field studies across Amazonia, we are now able to model species-soil relationships for many fern species and to place them into an evolutionary context with the help of molecular phylogenies. This makes it possible to analyze niche divergence both as an ecological phenomenon and as the result of an evolutionary process. We are carrying out such analyses using two fern genera, *Adiantum* and *Lindsaea*, as example cases. Both genera are common in the understory of
<figure><img src="image_168.png" /></figure>

Amazonian forests, and both have been suggested to be useful as indicators of forest types and soil properties, even though detailed models of their edaphic niches have not previously been available. Our results show that the species' edaphic niches are both relatively narrow and divergent, and that there are clear differences between the two genera. Currently ongoing analyses of niche evolution are expected to shed light on the evolutionary processes within Amazonia.

**S.68.5 Exploring ecological strategies in the five bean domesticated species (Phaseolus spp.)**

Diego E. Dávila¹, Julieta A. Rosell²

1 Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico. 2 Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico

Despite increasingly robust understanding of the drivers underlying ecological strategies in wild plants, the consequences of plant domestication on the expression of these strategies in crops remains poorly understood. For example, there is debate regarding whether the same patterns of trait covariation observed in wild plants are also found in crops, such as between the leaf (LES) and root economic spectra (RES). To explore patterns of trait covariation in crops, a system with high ecological variation, more than one event of domestication, and a long domestication history is ideal. Beans (Phaseolus spp.) represent such a system. The genus includes five domesticated species that represent independent instances of domestication, and hundreds of landraces that grow in a wide range of environmental and management conditions. Although domestication is predicted to produce strong shifts toward acquisitive strategies under the more stable and fertile conditions of agroecosystems, it is less clear whether it would favor uncoupling of the LES and RES. In this study, we cultivated 20 bean landraces (four per domesticated species) in a common garden at a Mexican temperate highland and measured nine functional traits in leaves, stems, and roots before the reproductive phase. Our results indicated that despite strong artificial selection, LES and RES are conserved in beans. However, we found evidence of decoupling between LES and RES, which has also been reported for other crops. There was also wide variation in mean values across landraces along a conservative-acquisitive continuum related to the ecological preferences of the species. This

work represents the first effort to understand the consequences of domestication on beans from a functional trait perspective. Understanding patterns and causes of trait correlations in crops is not only important for breeding efforts, but also for predicting plant responses in the context of climate change.

**S.68.6 Whitin individual phenotypic and epigenotypic effects of postfire resprouting on a Mediterranean shrub**

Jaime Saiz-Blanco¹, Conchita Alonso², Carlos M. Herrera², Juli G. Pausas¹

1 Centro de Investigaciones sobre Desertificación, CSIC, Valencia, Spain. 2 Estación Biológica de Doñana, CSIC, Seville, Spain

Although the ecological and evolutionary effects of wildfires on plants have been widely studied, thus far no attention has been given to the possible effects of wildfires on within-individual plant variability. This kind of variability affects both plant phenotype and epigenotype, and its deeply connected to plant animal interactions and maternal effects. In resprouting species, we hypothesize that wildfires can alter within-plant variability at both levels, since this process might lead to architectural changes and temporal homogenization of plant development. We also hypothesize that the relationship between epigenotype and phenotype might change. To test these ideas, we studied a population of the Mediterranean shrub *Anthyllis cytisoides* (Fabaceae) that was partially affected by a recent wildfire in Valencia. We selected plants that were resprouting after the wildfire as well as plants that were not affected by it to study leaf, flower, fruit and fecundity traits as well as epigenetic traits (i.e.,global cytosine methylation) at a within-individual level. By fitting mixed models to the data, we could see that most traits changed in within individual variance with postfire resprouting, although the sign of change was not always the same: weight related traits tended to be more homogenous within burned plants, while petal size and global cytosine methylation were more variable. In addition, the relationship between methylation level and petal size was not the same in burned and unburned plants. These results highlight the potential role of wildfires in shaping within individual variability of resprouting plants both at the phenotypic and epigenotypic levels and, thus in plant animal interactions and in maternal effects.
<figure><img src="image_169.png" /></figure>

# S.69 COLLECTIONS, HERBARIOMICS

## S.69.1 Museomics and targeted sequencing in Orthosiinae (Apocynaceae) yields undescribed diversity

Yam M. Pineda¹, Martha Kandziora²,
María Pinilla², Ulrich Meve¹, Sigrid Liede-
Schumann¹, Nicolai M. Nürk¹

1 University of Bayreuth, Bayreuth, Germany. 2 Charles University, Praha, Czech Republic.

Herbaria house an immense collection of plant diversity, primarily in the form of dry-preserved specimens. We present a work protocol in Apocynaceae aiming at advancing Museomic studies in plants using the Andean-centred Orthosiinae in the Neotropical Apocynaceae as model. Exclusively using herbarium specimens (n = 205), some of which are almost 200 years old, we optimised DNA extraction protocols and applied rigorous data processing on target capture sequencing (Hyb-Seq) data using Apocynaceae-specific set with 835 probes. A well-supported species phylogeny is presented comprising approximately 78% of the known species and >50 specimens not yet formally described. Phylogenetic results confirm the generic relationships and the common origin of the species in Orthosiinae. Here, we particularly focus on the relationships inside *Scyphostelma*, a mainly Andean genus with many undescribed species. We measured morphological traits and tested for significant differences among inferred clades, mainly in floral characteristics. We confirm the position of recently described *S. rotorum* and *S. solomonii*, originally suggested for morphological reasons to belong to the *S. harlingii* clade. Our study provides further evidence on the evolutionary relationships of Orthosiinae species. Obtained species trees serve as framework to study the biogeographical history of the group and to quantify how much of the species diversity can be explained by parapatric elevational replacement, which would hint towards ecological speciation (adaptive), and how much by parapatric speciation in isolation (neutral). Our investigation illuminates patterns of evolution of montane biodiversity in the Andes using Orthosiinae as a model group.

## S.69.6 Herbarium leaf spectroscopy and estimating functional traits from degraded specimens

Rykkar Jackson¹, Dominic Wood², Jordan Wilson-Morrison², Subbaiah Mechanda², Shan Kothari³, Warren Cardinal-McTeague¹

1 Department of Forest & Conservation Sciences, University of British Columbia, Vancouver, Canada.
2 Ottawa Research & Development Centre, Agriculture & Agri-Food Canada, Ottawa, Canada.
3 Département des sciences biologiques, Université de Québec à Montréal, Montréal, Canada

The estimation of leaf functional traits using leaf spectroscopy is a novel and underutilized technique in biological collections. With ~400 million plant specimens being held in ~3,500 herbaria worldwide today, there is massive potential for the use of spectroscopy on dried leaf samples. Once models are developed to quantify the limits of leaf spectroscopy on degraded herbarium specimens, such as those which have been stored for decades or centuries, we better know the extent to which we can use herbaria to estimate leaf functional traits through time. This research expands the application of collections-based leaf spectroscopy by quantifying the limits of specimen degradation in leaf spectral analyses. To do so, this project utilizes spectra from both fresh and dried leaves of *Ginkgo biloba*. Representative specimens were collected in 2022 from a hedgerow and pressed, dried for 48 hours, and assembled into the four treatments: one in a standard herbarium cabinet (control conditions) and three in growth chambers (18°C, 21°C, 24°C) to accelerate degradation. At this time, initial fresh-leaf spectral readings were conducted. In 2023, after 1 year within these treatments, the corresponding dried leaf spectra (350-2400 nm) were measured. This data will be used to analyze the effects of degradation on spectral analysis across treatment types by building an empirical model using multivariate techniques to estimate leaf functional traits via the use of least squares regression (PLSR). This research is among the earliest studies using PLSR modelling on intact dried leaves like those in herbaria, as previous models have been trained using the reflectance spectra of either fresh or ground, dried, but not intact, dried leaves.
<figure><img src="image_170.png" /></figure>

S.69.3 Frozen in time,
changing with climate:
Alpine endemics speak
through herbarium
genomics

Yasaman Ranjbaran¹,²*, Marco Canella¹,², Niccolò Forin¹,², Veronica Malavasi¹,², Rene Meissner³, Sven Winter³, Stefan Prost⁴, Francesco Dal Grande¹,²

1 University of Padua, Padua, Italy. 2 University Centre Botanical Garden, Padua, Italy. 3 University of Veterinary Medicine, Vienna, Austria. 4 University of Oulu, Oulu, Finland

The European Alps, undergoing a climate change rate twice as fast as global averages, present a unique opportunity to investigate the genomic responses of alpine flora to environmental shifts. For this project, we chose a few high-elevation, endemic alpine plants (e.g., *Rhizobotrya alpina* (NE), *Saxifraga tombeanensis* (EN)) to assess genomic changes over the past two centuries. For this, we employed a high-throughput genome resequencing approach on historical specimens from diverse herbariums across Europe spanning the last two centuries (1840-2023). By assessing allele frequency changes through time and comparing them with the extant genetic diversity we were able to directly gain insights into climate-driven allele loss and potential adaptations. This study not only sheds light on the evolutionary responses of alpine plants, crucial for their conservation, but also underscores the valuable application of genomics in leveraging natural history collections. The implications of our findings extend beyond the scientific realm, offering critical knowledge for informing conservation strategies and contributing to a deeper understanding of biodiversity in the face of rapid environmental changes.

S.69.4 Filling “big data”
needs for biodiversity
studies requires a diversity
of herbaria and continued
collecting

Jordan K. Teisher¹, Emily A. Humphreys²,
Cynthia Hong-Wa³, Cynthia Skema²

1 Missouri Botanical Garden, St. Louis, Missouri, USA.
2 Morris Arboretum & Gardens of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
3 Claude E. Phillips Herbarium, Delaware State University, Dover, Delaware, USA

Massive data resulting from herbarium specimen digitization have started a new era in biodiversity studies, often yielding highly cited publications and stimulating innovations in digitization and biodiversity informatics. A growing recognition of the value of herbarium data for research has, in turn, reinforced funding for digitization of collections. However, digitization grants are temporary and sometimes insufficient for their own goals. In addition, they greatly outweigh and outnumber the (capacity) grants available for collection curation/infrastructure and ongoing botanical collecting, activities also required to maintain the digitized data pipeline. Critically, projects using specimen data often lack any funding support for the herbaria housing those specimens. This situation presents an apparent paradox: herbaria have never been more impactful in terms of contributing specimen data to research, but at the same time, those contributions are increasingly hidden in data download files and burgeoning institutional acronym lists. Such under-acknowledgement exacerbates the long-standing collecting/ collections funding crunch. This may be most disadvantageous to smaller or more regionally focused herbaria, where funding needs are most acute. However, we argue that these collections are critical both for geographically equitable access to biodiversity collections and as repositories of specimens representing the spatial and temporal density needed for large-scale analyses. We use data from the Mid-Atlantic Herbarium Consortium (MAHC; https://midatlanticherbaria.org/) of the United States as a case study to examine how plant collecting in this region has contributed to the global data pool. We compare these data to mid-Atlantic specimens available through GBIF to evaluate the uniqueness as well as taxonomic, temporal, and geographic coverage of these specimens. With these analyses, we consider the varying roles of herbaria of different sizes and histories as data sources. We argue for greater support for botanical collecting and the continued support of a diversity of herbarium types to meet our biodiversity research needs.
<figure><img src="image_171.png" /></figure>

## S.69.5 Unlocking botanical treasures: RBG Kew's digitisation programme, challenges and learnings

Priscila A. Reis¹, Ellie Graves¹, Marie-Helene Weech¹, Sarah Phillips¹, Clare Drinkell¹, Alison Moore¹

1 Royal Botanic Gardens, Kew, Richmond, UK.

The Royal Botanic Gardens, Kew (RBG Kew), established in 1852, is home to one of the world's largest dried flora and fungi collections, safeguarding around 8.5 million specimens. It encapsulates a remarkable global coverage, containing over 95% of vascular plant genera and representing around 60% of the world's currently known fungi. Significantly, the herbarium serves as an invaluable repository of information for understanding the diversity of the world's living organisms, encompassing their morphological, genetic, physiological and ecological variations. However, most of these botanical treasures remain hidden behind cupboard doors, accessible primarily to academic communities through on-site visits. In turn, this constrains the research potential inherent in the collection. As part of a four-year digitisation program, RBG Kew is recognising this urgency and adapting to the digital era. The objective is to generate high-resolution images and data of the entire herbarium and fungarium collections, ensuring the preservation of the original specimens while unlocking global accessibility. This large-scale digitisation initiative involves overcoming substantial challenges, including the adaptation of workflows to address issues such as mould, pests, and damaged specimens. The Senior Curator Botanists in Digitisation are crucial to the success of the project. They maintain the integrity of the collection by providing intensive training and guidance to all digitisers involved, and by establishing protocols for resolving large-scale issues encountered during digitisation and reporting those issues to the appropriate team or individual. They also link the digitisation project and the core curatorial teams, ensuring constant communication on progress and mediating access to the collections for research while they are being digitised. The endeavour involves not just the conversion of physical specimens into digital formats but also requires the development of strategies to contend with the complexities presented by the collection's varied age and condition.

## S.69.6 New perspectives on wood collections: integrated collections at the UNAM Xylarium

Alí Segovia-Rivas¹, Mark. E. Olson², Marcelo Pace¹

1 MEXUw-Xylarium, Institute of Biology, Universidad Nacional Autónoma de México, Mexico. 2 Institute of Biology, Universidad Nacional Autónoma de México, Mexico.

Traditionally, xylaria or wood collections were conceived from a forestry perspective, primarily with the objective of serving as a reference for wood identification for commercial purposes. In the dynamic landscape of botanical collections, the UNAM Xylarium (MEXUw) in Mexico distinguishes itself by transcending traditional boundaries. Our collections encompass a diverse array of samples, organized into four subcollections: traditional wood blocks, entire stem fragments with wood and bark preserved in alcohol for all major orders of gymnosperms and angiosperms, wood anatomical slides, and cores and disks sampled for dendrochronological purposes. A pivotal aspect of our innovation lies in recognizing the unique preservation needs for quantitative wood anatomical studies. In response, the UNAM Xylarium houses an alcohol-preserved collection, a pioneering initiative that retains wood and bark characteristics often lost in conventionally treated wooden blocks subjected to drying, heat and cold. This approach ensures the protection of delicate features essential for comprehensive stem and root analyses. As part of these efforts, collections of wood slides are essential, but the digitalization of these assets remain a neglected frontier. Few institutions have ventured into digitizing their slide collections, and fewer still have made these digital archives publicly accessible, a frontier we are poised to address with the digital resources available at UNAM. Beyond physical and digital preservation, the UNAM Xylarium acknowledges the imperative to modernize organizational frameworks. We've updated all our collections to the APG-IV system, reflecting the most current nomenclature of plant families. The manual effort involved in this process is substantial and time-consuming, emphasizing the need for automation as collections grow and nomenclature evolves. Our presentation aims to highlight not only our advances in specimen preservation but also our commitment to staying at the forefront of organizational practices as we advocate for increase the donations and trades with other wood collections worldwide.
# S.70 INTEGRATIVE TAXONOMY OF MEDITERRANEAN PLANTS. SESSION 2

## S.70.1 The Azorean
*Daucus*: a morphological, cytogenomic, phylogenetic and ecological study

Guilherme Roxo¹, Mark Carine², Ann Mc Cartney³, Elisabete Dias¹, Amélia Vaz¹, Pedro Talhinhas⁴, Maria Manuel Romeiras², Rubén M.C. Rego¹, Christian Zidorn⁵, Luís Silva¹, Mónica Moura¹

1 University of Azores, School of Sciences and Technology, Ponta Delgada, Portugal. 2 The Natural History Museum, London UK. 3 Genome Institute, University of California, Santa Cruz, California, USA. 4 Instituto Superior de Agronomía, Universidade de Lisboa, Tapada da Ajuda, Lisbon, Portugal. 5 Pharmazeutisches Institut - Abteilung Pharmazeutische Biologie Christian - Albrechts-Universität zu Kiel. Kiel, Deutschland

The genus *Daucus* L. contains approximately 45 species, the majority of which are found in the Mediterranean region. The *Daucus carota* complex includes ca. 25 infraspecific taxa, for which there are no or only poorly developed barriers to interbreeding between the wild and domesticated forms. In the Azores archipelago two sub-species occur: the endemic *Daucus carota* subsp. *azoricus* Franco, and the native *Daucus carota* subsp. *maritimus* (Lam.) Batt. Due to the phenotypic diversity observed across the *Daucus carota* complex, the distribution and diagnostic morphological characters of the endemic Azorean species remain unclear. This study aims to clarify the taxonomy of the *Daucus carota* complex in the Azores and determine if the *Daucus carota* subsp. *azoricus* Franco is in fact a distinct taxon. For this purpose, we used molecular, cytogenomic, morphological and ecological data. A total of forty-four specimens of *Daucus carota* subsp. *azoricus* were sampled across the nine islands of the archipelago and the ITS region and the COS region (CA7) sequenced. Estimations of DNA content were performed with flow cytometry to investigate variation between taxa (i.e., *Daucus carota* subsp. *azoricus* and *Daucus carota* subsp. *maritimus*) and populations. Moreover, we measured a total of 31 morphological characters from across the stem, inflorescences, flowers, and fruits. Finally, we performed germination tests in order under-

stand the phenotypical diversity observed and cultivating *Daucus carota* subsp. *azoricus* under different climates and soils. Preliminary results indicate that there are no major morphological differences between the sampled sites. Similarly, with cytogenomic data it was not possible to discriminate between the two subspecies. However, the molecular data revealed variation across the archipelago with different haplotypes obtained from the screened regions.

## S.70.2 Disentangling relationships in different lineages of *Euphorbia* subgen. *Esula* (*Euphorbiaceae*)

Božo Frajman¹

1 Department of Botany, University of Innsbruck, Innsbruck, Austria

*Euphorbia* subgenus *Esula* is the earliest diverging lineage within *Euphorbia* and with roughly 480 species represents the most significant radiation of the genus in temperate areas of the Old World, with highest diversity in the Mediterranean and Irano-Turanian regions. The overall infrageneric structure has been largely resolved using plastid and nuclear ITS sequences, leading to recognition of 21 sections. In contrast, spatio-temporal diversification within the sections – and partly also the relationships among them – remain poorly understood. I present the outcomes of ongoing studies on the diversification of different species groups within *Euphorbia* sect. *Esula* based on an integrative approach using phylogenetic and phylogenomic data, relative genome size and chromosome number estimations, as well as morphometric and ecological analyses. They are all important for inferring inter-specific boundaries and establishing a stable taxonomy within the subgenus. I address the significance of polyplois disation for diversification within the subgenus and summarise major open questions to stimulate further research on this fascinating group of flowering plants.
<figure><img src="image_172.png" /></figure>

### S.70.3 Excessive polyploidy and unusual pattern of pollen stainability in Gagea and Ornithogalum species

Michal HRoneš¹, David Horák¹, Gabriela Stryhalová¹

1 Department of Botany, Palacký University in Olomouc, Olomouc, Czech Republic

Geophyte monocots with their showy flowers are a prominent component of the Mediterranean flora. However, they remain taxonomically challenging due to their low vegetative morphological variability and the presence of polyploidy. We studied genome size as a proxy for ploidy level of selected taxa of Gagea (Liliaceae) and Ornithogalum (Asparagaceae) and we also established their pollen stainability. We asked whether genome size can be used for taxa determination and whether pollen stainability correlates with established ploidy level. We expected a normal pattern of pollen stainability with diploids having the highest proportion of well-developed pollen and even ploidy cytotypes having higher stainability than odd ploidy cytotypes. In both genera, we found an excessive occurrence of polyploidy ranging from diploids to heptaploids. The studied taxa differed in genome size also on the same ploidy level suggesting that genome size can be used for taxa differentiation. Quite surprisingly, pollen stainability varied greatly and it did not follow the expected pattern with higher ploidy and odd ploidy cytotypes usually having a higher proportion of well-developed pollen. A simple mechanistic explanation of this pattern is lacking. Lower stainability in even ploidies suggests past hybridisations and/or meiotic aberrations.

### S.70.4 Phylogeny and biogeography unveil taxonomic deflation in the Mediterranean disjunct genus Jasione L. (Campanulaceae)

Miguel Serrano¹

1 Department of Botany, Faculty of Pharmacy, University of Santiago de Compostela, Santiago de Compostela, Spain

Jasione is a taxonomically complex genus with a disjunct east-west Mediterranean distribution pattern. Around 16 species are currently recognized, although more than one hundred taxonomic names have been proposed. The hypothesis that intense morphological stasis is concealing evolutionary relevant variability and hampering correct understanding of the evolutionary relationships in the genus needs to be tested. Internal phylogenetic relationships are investigated after a comprehensive sampling including different populations from most of the proposed names, to prevent a priori exclusion of evolutionary significant lineages. The underlying processes leading to the disjunct east-west Mediterranean distribution pattern are discussed. To address these questions, a five cpDNA loci time-calibrated phylogeny was constructed with 111 terminals. The lineage leading to Jasione originated in the late Oligocene (c. 25 Mya) and the extant lineages of Jasione derive from a much later diversification event, occurring in c. 9 Mya in the Miocene, from an ancestor most probably originated in the western Mediterranean region. Two main clades can be identified, one only present in the western Mediterranean and encompassing species with very different morphologies and another with the extant disjunct distribution pattern. The second clade began to diversify at the beginning of the Pleistocene, probably in the Balkan Peninsula, and at least two east to west dispersal events are identified in this clade, with niche modelling identifying niche conservatism in the eastern group and niche expansion in the western group. The disjunct pattern results from a dynamic biogeographic process in which the two extant areas provided the opportunity both to remain and to disperse, increasing the chances of the lineage to endure. Morphological stasis in Jasione led to taxonomic deflation and integrative approaches are addressed. Internal coherence and discontinuities are tested integrating information from key traits, ploidy, ecological niche and adequacy to biogeographical units to support "cryptic" species hypotheses.

### S.70.5 Integrative taxonomy and biogeography of Umbilicus (Crassulaceae)

Lucas L. Miller¹, Maria Cristina Duarte², Mónica Moura³, Maria M. Romeiras²,⁴, Christian Braeuchler⁵, Mathieu Chambouleyron⁶, Hanno Schaefer¹

1 Technical University of Munich, Freising, Germany.
2 University of Lisbon, Campo Grande, Portugal.
3
<figure><img src="image_173.png" /></figure>

Universidade dos Açores, Ponta Delgada, Portugal.
4 Instituto Superior de Agronomia, Universidade
de Lisboa, Lisbon, Portugal.
5 Oberösterreichische
Landeskultur GmbH, Linz, Austria.
6 Reneco Interna-
tional Wildlife Consultants LLC, Rabat, Morocco

Umbilicus is a small genus of Crassulaceae with a distribution ranging from the Mediterranean region to Macaronesia, sub-Saharan Africa, and West Asia. The number of species is unclear due to the controversial taxonomy with multiple unresolved taxa and characters traditionally used for species delimitation being rather ambiguous. So far, only genetic analyses at the family level with a very limited number of Umbilicus species have been available. Here, we sequenced six plastid genes and spacers (matK, psbA-trnH, rps16, trnQ, trnS and trnL) plus the nuclear ribosomal ITS region of 235 specimens covering most of the distribution range of the genus and most described taxa. We inferred phylogenies with maximum likelihood and Bayesian methods and studied the morphology of herbarium material and photos of observations on iNaturalist. Using Bayesian molecular clock dating with secondary calibration we estimated a stem age of 14 (+/- 6) Million years for the genus. We inferred West Asia as the geographic origin with Chiastophyllum as sister lineage. The first diverging clades including U. albido-opacus and U. luteus as well as species with a paniculate inflorescence are restricted to West Asia, northeast Africa, and southeastern Europe. The remaining species, which all exhibit a racemose inflorescence and mostly greenish tubular flowers, diverged 9 (+/- 6) Ma ago and repeatedly colonized Africa, Europe, and Asia. Within this clade we inferred several cases of long-distance dispersal, most notably the colonization of Cameroon, Angola, and India as well as several independent colonization events of the Macaronesian islands. More data on the pollination biology of the genus, including pollinator shifts and transitions to selfing, will help us understand the discovered phylogenetic patterns.

S.70.6 Unveiling the genetic
tapestry: exploring SNPs in
the Cyclamen genus

Khalid Aldhuwaib¹, Alastair Culham¹

1 School of Biological Sciences, University of Reading, UK.

Cyclamen is a genus of 23 perennial flowering plants belonging to the Primulaceae family valued both horticulturally and evolutionarily. Cyclamen species are found throughout Europe and the Mediterranean Basin, from the Caucasus to Iran, with one species found in Somalia. However, despite its significance, understanding the underlying genetic diversity and phylogenetic relationships among Cyclamen species remains a challenge. Here, we investigate plastid single nucleotide polymorphisms (SNPs) using paired-end sequencing data in order to unravel the complex evolutionary relationships and variation among Cyclamen species. These SNPs were subjected to strict filtering criteria to ensure robustness and reliability in subsequent analyses and to remove low quality and false positive calls. Our findings could provide pivotal insights for future studies and conservation efforts, as well as a deeper understanding of the evolutionary history forming this genus. Phylogenetic methods and network analyses based on plastid SNPs would enable assessment of genetic structuring and species delimitation concordant with earlier morphological and molecular classifications.
# S.71 BIOLOGICAL DIVERSITY HIDDEN IN EARLY TERRESTRIAL SITES OF EXCEPTIONAL PRESERVATION.

## S.71.1 Permineralized plants from the Lydiennes Formation (France): a unique record of early Carboniferous plant diversity and biology

Anne-Laure Decombeix¹, Thibault

Durieux¹,², Carla J. Harper², Brigitte Meyer-

Berthaud¹, Jean Galtier¹

1 UMR AMAP, Univ. Montpellier, CNRS, CIRAD, INRA, IRD, Montpellier, France. 2 Department of Botany, Trinity College Dublin, Dublin, Ireland

The earliest Carboniferous (ca 360-330 Mya) is a pivotal time in plant evolution, with the transition between taxa that characterized the first complex plant communities during the middle to late Devonian and more modern groups that later became major elements of the iconic “coal swamps” vegetation of the Late Carboniferous. However, localities with well-preserved fossil plants from that time period are rare worldwide, especially anatomically preserved remains that yield important information on the evolution of plant structure and biology. In Southern France, middle Tournaian anatomically preserved plants were first reported in the Lydiennes Formation near Cabrières (Hérault) in the late 19th century. Since that time, at least 21 genera have been identified, some of them unknown elsewhere. We present a synthesis of our knowledge of this exceptional fossil flora based on around 450 specimens from the collections of the University of Montpellier, France. The assemblage comprises a mixture of taxa belonging (1) to groups that were abundant and diverse during the Devonian and dwindled during the Carboniferous, such as the cladoxylopsids s.l. and progymnosperms, and (2) to groups that appeared in the Late Devonian and became emblematic members of Late Carboniferous floras such as the Sphenophyllales, Zygopteridalean ferns, and seed plants. In terms of relative abundance, the assemblage is largely dominated by seed plants (>60%). Zygopteridalean ferns, cladoxylopsids, and lycopsids are also relatively

abundant (+/- 10%), while the progymnosperms and sphenopsids are rare (1-2%). Anatomically preserved stems and petioles are the most abundant type of remains, while roots and reproductive structures are uncommon. Some of the fossils exhibit an excellent preservation that allows detailed inferences on plant autoecology (e.g., adaptation to aquatic environments), architecture (e.g., the oldest evidence of axillary branching), or development.

## S.71.2 The resupinate strobilus spikemoss in the Cretaceous amber might be associated with the rainforest shade aggravation

Qiaoping Xiang¹, Tongxin Ye¹, Xianchun

Zhang¹

1 Institute of Botany, Chinese Academy of Sciences, National Botanic Gardens, Beijing, China

Selaginellaceae is a Paleozoic origination with a cosmopolitan distribution. Previous fossil evidence indicates the rainforest floor origin of modern spikemoss and an ecological association between Selaginellaceae and the humid tropics since the Paleozoic. We observed a 99-million-year-old and well-preserved spikemoss branch with the character of resupinate strobilus in mid-Cretaceous Kachin amber, which provides a precious window to glimpse the Selaginellaceae diversification and its specialized habitat. To explore the resupinate strobilus evolution history, we built up the phylogeny including more than 85% resupinate strobilus species, estimated the divergence time, and reconstructed the ancestral state of the sporophylls arrangement and habitat. Resupinate strobilus first appeared in the Early Cretaceous within the Tropical Asia clade and later paralleled in other clade, with the occurrence times strongly related to the rise of angiosperm. In combination with their low-light adaptability and the difference in light response of dimorphic leaves, we further suggested that the current tropical
<figure><img src="image_174.png" /></figure>

spikemoss diversity originated since the Cretaceous (after angiosperm origin) instead of the evolutionary holdovers from the Paleozoic tropical forest and conjectured the resupinate strobilus was a key innovation of the ground-floor spikemoss adapting to the humidity and shadow rainforests.

### S.71.3 Unravelling the diversity of plants and their associated organisms in Devonian and Carboniferous cherts

Christine Strullu-Derrien¹,², Alan RT Spencer¹,³, Frederic Fercoq⁴, Raymond Wightman⁵, Paul Kenrick¹, Sebastian Schornack⁶, David Hawksworth⁷,⁸,⁹, Andrew H Knoll¹⁰

¹Science Group, The Natural History Museum, London, UK. ²Institut Systématique Évolution Biodiversité, Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, Paris, France. ³Department of Earth Science & Engineering, Imperial College London, London, UK. ⁴Unité Molécules de Communication et Adaptation des Micro-organismes, Muséum national d'Histoire naturelle, CNRS, Paris, France. ⁵Sainsbury Laboratory, University of Cambridge, Imaging facility, Cambridge, UK. ⁶Sainsbury Laboratory, University of Cambridge, Cambridge, UK. ⁷Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, UK. ⁸Jilin Agricultural University, Changchun, Jilin Province, China. ⁹Geography and Environmental Science, University of Southampton, Southampton, UK. ¹⁰Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA

Sites of exceptional preservation such as the Devonian Rhynie cherts (Scotland, UK) and the Carboniferous Esnost chert and Grand'Croix cherts (Massif Central, France) preserve remarkable records of early terrestrial ecosystems. The cherts at Rhynie formed as deposits from a hot spring system. Fossilization occurred through episodic inundation of the biota with fluids from a nearby hot-spring system, and the resulting silicification preserved organisms in exquisite detail. Alongside plants, a community of animals, primarily arthropods, and diverse microscopic organisms, including cyanobacteria, algae, amoebozoa, oomycetes and various fungal groups have been described from these sites. At Esnost cherts formed in acidic volcanoclastic sediments associated with peat deposits (now anthracites). At Grand'Croix silicification of the

plants was related to silica-charged waters produced during chemical weathering of earlier volcanics. Fossilization preserves both *in situ* plants and transported plant fragments. Preservation is excellent, but the plant remains are fragmentary. In addition to plants, fungi and oomycetes have been documented. The development of Confocal Laser Scanning Microscopy (CSLM) has provided us with a new tool to investigate the biodiversity of these unique sites. Unlike traditional bright-field microscopy, CSLM enhances the image's clarity and detail. Recently we used Fluorescence Lifetime Imaging (FLIM) that delivers information about the spatial and chemical distribution of fluorescent material together with information about its nano-environment. These approaches allow us to document minute three-dimensional structures with unprecedented precision. We present our latest findings on cyanobacteria, testate amoebae, fungi and oomycetes from the Rhynie chert, showing that the components of the bacterial mats among which plants grew were already highly diversified. With the addition of new results on symbiotic and pathogenic fungi and of the newly described oomycetes from the French cherts, we show an increasing knowledge of the diverse interactions that took place in early terrestrial ecosystems.

### S.71.4 Uncovering the origins of plant complexity in the Rhynie chert

Alexander J. Hetherington¹

¹University of Edinburgh, Edinburgh, UK.

Land plants exploded in complexity during the Silurian and Devonian periods during the primary radiation of vascular plants. This radiation saw plants diversify from tiny species, that we predict occupied marginal habitats, and culminated in the origin of the first forests covering large swathes of the terrestrial surface by 385 Mya. The diversification of vascular plants occurred in parallel to, and was likely underpinned by, the origin of the modern vascular plant sporophyte body plan delineated into distinct roots, shoots and leaves and connected by a highly efficient vascular transport system. Despite the evolution of the vascular plant body plan being one of the most important events in plant evolution many key questions still remain about how and when it evolved. The fossil record provides our only direct evidence for the steps involved in the evolution of the complex vascular plant body plan and despite its biased and frag-
<figure><img src="image_175.png" /></figure>

mentary record it remains invaluable for shaping our understanding of plant evolution. Numerous fossil sites from around the world have helped shape our views on the diversification of vascular plants but one of the most important fossil sites has been the Rhynie chert from Aberdeenshire, Scotland. This single fossil site, preserving an entire 407 million year old ecosystem with exceptional preservation, has been transformative for plant evolution. Despite being discovered over 100 years ago new imaging and digital reconstruction techniques are underpinning a resurgence of research on the site. Here I present recent advances in our understanding of the plant species in the Rhynie chert and outline how these fossils are contributing to our understanding of the evolution of plant complexity.

## S.71.5 Aglaophyton and Rhynia: ecology, growth and life strategies of the two most common Rhynie chert land plants

Hans Kerp¹ and Michael Krings²,³

1 Universität Münster, Münster, Germany. 2 Bayerische Staatssammlung für Paläontologie und Geologie, Munich, Germany. 3 Ludwig-Maximilians-Universität, Germany

Aglaophyton major and Rhynia gwynne-vaughanii are commonly regarded as the less advanced plants from the Early Devonian Rhynie chert. The naked, dichotomizing axes with a simple conducting system were lying on the substrate and lacked root-like structures or rhizomes. Despite their apparent simplicity these plants had rather complex life strategies. The alternation of generations in these two taxa can be reconstructed in great detail, and the excellent and rapid fossilization in the chert even provides snapshots of the release of sperm and the gametophyte-sporophyte junction. Cyanobacterial mats appear to have been crucial for the germination of spores. A symbiosis with vesicular arbuscular mycorrhizal fungi is characteristic of both taxa and was established already in the early gametophyte stage. Aglaophyton hosted several other organisms, including cyanobacteria, mites, trigonotarbid spiders and the oldest known bona fide nematodes, the first soft-bodied animals recorded from the Rhynie chert. Apart from sexual reproduction Rhynia also propagated vegetatively.

## S.72 CITIZEN SCIENCE INITIATIVES FOR THE PROMOTION OF BOTANY

### S.72.1 A citizen science initiative to monitor urban plant biodiversity

Nathalie Machon¹, Vanessa Laine²

1 Centre d'Ecologie et des Sciences de la Conservation (MNHN, CNRS, Sorbonne-Université), Paris, France. 2 Tela Botanica, Montpellier, France

"Sauvages de ma rue" (Wild Plants of My Street) is a French citizen science program of Vigie-nature, developed by the National Museum of Natural History and Tela Botanica. Focused on the flora of public spaces in cities, it encourages urban residents to conduct a floristic inventory of their street and submit the data on a website developed by Tela Botanica. Two objectives guided the development of this program: an educa-

tional goal to help urban dwellers recognize the plants growing in their daily environment and a scientific goal to understand the ecological role of vegetated micro-spaces (tree bases, walls, pavement cracks, etc.) in the overall functioning of urban biodiversity. This project, initiated in 2011 in the Île-de-France region, was expanded to the entire metropolis in 2012. After about a decade, around 100,000 data points had been collected. This presentation will provide an overview of the list of volunteer participants in the program and the motivations they express. The primary observation is that, in the initial years, individual volunteers submitting data independently have given way to more formalized organizations such as associations, schools, and local authorities, driven by diverse motivations. Additionally, we delve into the scientific outcomes derived from the program.
<figure><img src="image_176.png" /></figure>

## S.72.2 Photographic field guide to the common grasses of Madagascar

Rafael F. de Almeida¹, Nantenaina Rakotomalala², Fenitra N. Randrianarimanana², Lorna MacKinnon¹, David Rabehevitra², Francois Rousseu³, Lucien Rakotonirina², Dina Miarinjanahary⁴, Nirintsoa Landry Raharinirina², Mamy Tiana Rajaonah², Tiana Randriamboavonjy², Livasoa Randriamanalina², Cédrique Solofondranohatra⁵, Mijoro Rakotoarinivo⁶, Olinirina Nanjarisoa², Jean A. Randriamampianina⁷, Botovao Auguste Ramiandrisoa⁸, Maria S. Vorontsova¹

¹Royal Botanic Gardens, Kew, UK. 2 Kew Madagascar Conservation Centre, Antananarivo, Madagascar. 3 University of Sherbrooke, Canada. 4 Missouri Botanical Garden, Madagascar. 5 Madagascar Biodiversity Centre, Madagascar. 6 University of Antananarivo, Madagascar. 7 FOFIFA/CENRADERU, Madagascar. 8 University of Mahajanga, Madagascar

The grasses and grassy ecosystems of Madagascar have been the focus of Kew's multidisciplinary research, conservation, and development work since 2011, including taxonomic, phylogenetic, ecological and agricultural projects. Madagascar is home to an estimated 38 million hectares of grasslands comprising 146 genera and ca. 590 Poaceae species, of which ca. 220 are endemic to this island. Unfortunately, the lack of specialist expertise and resources has led to a lack of recognition and a failure to utilise this diversity. Madagascar's first colour picture guide to grass genera was printed by Kew in 2018. Field photography of grasses has always been challenging due to their small reproductive organs while living grasses are not easy to recognise from traditional line drawings of spikelets. Using specialist photography training and multiple photographer contributions, we are creating the first photographic guide to species to create a foundational resource for identifying, managing, and using common grasses, making native and endemic forages better known and more valued by the Malagasy people. This bilingual book in English and Malagasy will include 127 genera and

300 species of common and economically significant grass species. Photographs were taken on field trips from 2011 to the present. Ethnobotanical data are gathered from literature as well as smallholder interviews. Morphological traits, distribution, ecology, and economic uses are compiled from GrassBase, project datasets and partner organisations. Field photographs are being edited using Photoshop software, focusing on habits, leaves, spikelets, and caryopses as a rich visual resource for diverse audiences.

## S.72.3 Leveraging machine learning and citizen science data to describe flowering phenology across South Africa National Botanical Garden

Ross D. Stewart¹, N. Bard³, M. van der Bank², T. Jonathan Davies²,³

¹Sol Plaatje University, Kimberly, South Africa. ²Afrikan Centre for DNA Barcoding, University of Johannesburg, Auckland Park, South Africa. ³University of British Columbia, Vancouver, British Columbia, Canada

Phenological patterns, representing the timing of recurrent biological events, such as flowering, are essential for understanding plant life cycles, ecological interactions, and how species respond to climate change. However, given the diversity of South African flora (ca. 24,000 species), manually recording species phenology presents an immense challenge. In this study, we explore machine learning (ML) application to data sourced from the iNaturalist database and describe the flowering phenology of plants in the South African National Botanical Gardens. We generated a training dataset from 10,000 photographic images, encompassing a diverse range of species from various locations. Next, we applied a Convolutional Neural Network (CNN) to classify images as flowering versus non-flowering. Using metadata associated with each image, including the date the photograph was taken, we were able to derive the timing of peak flower production and length of the flowering season for each species in the database. Our analysis illustrates how ML can leverage the vast wealth of citizen science biodiversity data in South Africa and describe large-scale phenolog-
<figure><img src="image_177.png" /></figure>

ical dynamics across the region. Applying ML and other advanced data tools to big data provides an opportunity for more informed decision-making and sustainable practices in the context of biodiversity conservation and management.

## S.72.4 BOTASCOPIA - An open access collaborative collection of descriptions of plants species

Xavier Aubriot¹, Sophie Nadot¹, Manon Villa²

1 Laboratory Ecology, Systematics and Evolution, University Paris-Saclay, Gif/Yvette, France. 2 Tela Botanica, Montpellier, France

The teaching of Botany in France faces a paradox: waning support in academia contrasts with burgeoning public interest in plant knowledge. The success of French Botanical MOOCs reflects this unprecedented public enthusiasm. In that context, standardized descriptive sheets serve as vital pedagogical tools, offering comparability and accessibility in cataloging vegetation. In 2022, building on a first set of handmade descriptive sheets, researchers from University Paris-Saclay united with pedagogical engineers and informaticians of the French association Tela Botanica to design an open access collaborative botanical knowledgebase, BOTASCOPIA. This platform, curated by experts from different fields (botany, agronomy, ecology), invites continuous contributions from a broad audience. Input fields welcome a variety of data related to plant morphological, ecological and agroecological traits, and have been designed to maximize comparability and extraction of the data, as well as to balance the accuracy of the descriptions with the complexity of the botanical concepts. BOTASCOPIA strives for data traceability and citation of the essential references is a requirement. As output, all the data entered are available online and a subsample can be assembled into nice-looking and illustrated pdf sheets. Initially a pedagogical tool, BOTASCOPIA evolution is now directed towards broader accessibility and should ultimately be part of a larger naturalistic package that will include customizable Bayesian-inference based identification keys. Continual enhancements in structure and interface cater to BOTASCOPIA usability, promising a robust resource for botanical education and research.

## S.72.5 TEPIK - A resource for testing and teaching plant identification and botanical knowledge

Valéry Malécot¹

1 Département d'Ecologie, L'Institut Agro Rennes Angers, Angers, France

Learning plant names is usually considered as a complex and long process, which is even more complex when additional information is added (such as plant size, flowering period, leaf deciduousness, ...). We present the produce of our reflexions in the form of a database associated with a quiz generator, called TEPIK (for Test of Plant Identification and Knowledge). These reflexions have been done with the support of various professional groups and teachers. The produced tool, considered as a complement to teaching with living material, consist in a database fed by certified and free or licensed data. The main feeding sources are efoire from Tela Botanica and Floriscope from Plante&Cité. Selection of the current taxa is based on wild and commercial frequency but any new taxa may be added if needed. For each taxa (more than 4000 are currently included) various characteristics and numerous pictures are present. Each picture is tagged in such way that the part of the plant presented is known by the system. Difficulty parameters are also implemented, whether they rely on the plant (i.e.,some plant parts are more difficult to recognise), on questions (open questions are more difficult that single-choice questionnaire) or on information tested (knowing common name less difficult to learn than soil type). Teachers can generate sets of questions on a precise list of plants, with more or less detailed parameters in order to provide quiz to their students. In addition, thoughts on learning progression are currently developed with Bayesian Knowledge Tracing in order to follow and predict knowledge acquisition.

## S.72.6 Breaking the negative trend: Can iNaturalist help boost species knowledge?

Stina Weststrand¹,², Åsa Krüger¹,²

1 Gothenburg Botanical Garden, Gothenburg, Sweden. 2 Gothenburg Global Biodiversity Centre, Gothenburg, Sweden
<figure><img src="image_178.png" /></figure>

In Sweden, as in many other countries, species knowledge is in decline. There are fewer specialists to teach the next generation and to update floras and keys. We need to use everything we can to help turn this trend around! Engage the general public as well as students at all levels. iNaturalist is a powerful tool in citizen science, such as a bioblitz or inventory competitions. Not only will people get a proposed species name for their observation, they will also be adding valuable data that later can be used in research. When scientists and other experts help identify the observations, a valuable direct link between the scientific community and the public is created. The project function in iNaturalist is a usable asset in for example a floristics course and will make data from inventory projects accessible to the community. We show examples from both a bioblitz for the general public and a floristics course at the University of Gothenburg, Sweden.
<figure><img src="image_179.png" /></figure>

Symposia Session 5

**S.73 PLANT RESPONSES TO STRESSES AND CLIMATE CHANGE. SESSION 3**

**S.73.1 An overview on the "multi-tasking" enzyme phytochelatin synthase in plants**

Luigi Sanita' di Toppi¹

1 Department of Biology, University of Pisa, Italy

My contribution deals, in an evolutionary perspective, with "traditional" and new roles of the phytochelatin synthase enzyme (PCS), the functions of which still appear shrouded in a degree of mystery. I illustrate and discuss the five main key-points that characterize this peculiar "multi-tasking" enzyme in plants: 1) PCS is a "papain-like" Clan CA cysteine peptidase; in particular, the eukaryotic PCS is a gamma-glutamylcysteine-dipeptidyl-(trans)peptidase. 2) PCS is constitutively expressed in plants, algae, lichen chlorophyte photobionts, as well as in other eukaryotes, such as Fungi, some Animalia and Amoebozoa, SAR (especially Bacillariophyceae and Phaeophyta) and, more rarely, Excavata. Moreover, prokaryotic PCSs, which possess significant sequence homologies with those of plants, have been identified in cyanobacteria and in some proteobacteria. 3) Through its transpeptidasic products - i.e., the metal(loid)-binding oligopeptides named phytochelatins (PCn) - PCS detoxifies toxic heavy metals and metalloids (e.g., cadmium, lead, mercury, arsenic, etc.), but can also help regulate the homeostatic needs of metal micronutrients such as iron, zinc, and copper. 4) Being a peptidase (see point 1), PCS can also hydrolyze GSH and GS-conjugated xenobiotics in the cytosolic environment through the cleavage of glycine from GSH. The GS-conjugation capacity of plant PCSs is a feature also detected in prokaryotic PCSs, and the breakdown of GS-conjugates may accordingly be considered a primigenial function of PCS, perhaps older than the biosynthesis of PCn. 5) Lastly, a yet limited number of experimental works is increasingly highlighting the importance of PCS in plant defence against phytopathogens, essentially

in terms of microbe-triggered-immunity. Advances in the overall area of knowledge on PCS may well help clarify the evolutionary history and function(s) of this ubiquitous and partly mysterious "multi-tasking" enzyme.

**S.73.2 Growth, antioxidative defense, and yield responses of four pearl millet cultivars under elevated UV-B radiation**

Pooja Singh¹, Krishna Kumar Choudhary¹*

Department of Botany, MMV, Banaras Hindu University, Varanasi-221005, India. *kkc@bhu.ac.in

Ultraviolet (UV-B) radiation is a well-known potent stress factor on this Earth's surface caused by stratospheric ozone depletion, which alters morphological, physiological, cytological, and biochemical traits in plants. However, its impact on underutilized plant species such as pearl millet is less explored and further, the question of global food security under climate-changing scenarios can be ascertained. This encouraged the present study to investigate the effects of elevated UV-B (eUV-B) radiation (ambient+7.2 kJm⁻²d⁻¹) on four cultivars of pearl millet (HHB-272, HHB-67, MPMH-21 and MPMH-17) during May to August 2023 under ambient conditions in the Indo-Gangetic plains of India. Maximum increase in plant height (20%), no. of leaves (31.2%), leaf area (35.4%), and panicle length (60%) was recorded in HHB-272 at grain-filling stage (GFS). Superoxide radicals were initially higher in MPMH-21(47.3%), MPMH-17(28.6%) at panicle development stage (PDS), but later decreased by 35.5%, and 15.3% at GFS. To counter oxidative stress, maximum increase in SOD activity was recorded only at PDS in MPMH-21(35.9%), MPMH-17(34.8%), while declined in all the tested cultivars at GFS. Highest phenolic and flavonoid contents was reported at GFS in MPMH-
<figure><img src="image_180.png" /></figure>

21(97.2%, 41.7%), and MPMH-17(6.9%, 14.9%), respectively. Oxidative damage in terms of malondialdehyde (MDA) content was significantly higher in MPMH-21(46.3%), and MPMH-17(25%), while declined at GFS due to increased phenolic and flavonoid contents, respectively. Yield of tested cultivars was not adversely affected under eUV-B in an ambient tropical condition, but the response varied between them. Grain yield (g m⁻²) increased significantly in HHB-272(30.2%), HHB-67(55.8%), MPMH-21(83.3%), and MPMH-17(28.6%), respectively. Further investigations are required to assess the impact of elevated UV-B on grain quality characteristics that will be helpful to address the question of food security as well as malnutrition challenges.

### S.73.3 Disturbance and nutrient enrichment impacts on plant community dynamics: contributions to a global study

Lydia R. O'Halloran¹, Justin Robbins¹, Thomas O'Halloran¹

1Baruch Institute of Coastal Ecology and Forest Science-Clemson University, Georgetown, South Carolina, USA

Herbaceous-dominated ecosystems are found throughout the world in diverse locations that differ in their climate and edaphic factors. This is reflected in a wide range of annual above- and belowground biomass production, plant diversity and canopy density between these ecosystems. Our study aims to understand how nutrient availability and disturbance impact soil trace gas fluxes and how this relates to plant species relative abundance, diversity, and annual aboveground production. Here, we present data on herbaceous-dominated ecosystems found in coastal South Carolina, USA. This study is part of a global network (DRAGNet) of herbaceous-dominated ecosystem study sites distributed globally using identical protocols for treatment application and data collection. We found the relationship between plant species diversity and aboveground biomass production varies. Aboveground biomass and accumulated litter were not correlated, suggesting that the drivers for carbon assimilation and decomposition are different. The combination of disturbance and nutrient enrichment lead to greater CO₂ and CH₄ fluxes, while the relationship

between N₂O and the treatments is less clear. This research will serve as the foundation for future research on how nutrients and soil disturbance interact with the amount of carbon assimilation, and if some species show trait variation in response to these treatments in different regions of the world.

### S.73.4 Enhancing crop production in acidic soil by mitigating aluminium toxicity

Bhumi N. Tripathi¹, Vijetna Singh¹, Babita Chaudhary¹, Rimjhim Joshi¹

1 Department of Biotechnology, Indira Gandhi National Tribal University, Amarkantak, 484887, Madhya Pradesh, India

Wheat is a globally significant staple grain crop due to its high nutritional content and adaptability to a variety of agroclimatic situations. Wheat output must rise on current agricultural acreage to avoid agricultural expansion. Most wheat-growing locations face soil restrictions, including acidity, which hinders crop productivity. Due to excessive usage of ammonium-containing fertilizers and acid rain, 30-40% of global arable soil is acidified. Aluminum (Al) toxicity limits plant development in acidic soil. In Raj 3077, an Al-resistant wheat genotype, an antioxidant defense mechanism against Al-induced oxidative damage and external malate detoxification provides Al-resistance. Raj 4120 (Al-sensitive) inhibited growth more than Raj 3077. Both genotypes' roots were tested for lipid peroxidation and H₂O₂ concentration. These indicators were greater in Raj 4120 shoots, indicating oxidative stress. Antioxidant enzymes as SOD (EC 1.15.1.9), CAT (EC 1.11.1.6), and APX (EC 1.11.1.11) protected Raj 3077 against Al-induced oxidative damage. Inefficient antioxidant enzyme activity in Raj 4120's roots indicated severe oxidative damage and a greater number of harmful Al ions translocated to the shoot, creating Al stress there. Interestingly, Raj 4120's shoot had more CAT activity than Raj 3077, but it wasn't adequate to counteract Al-induced reactive oxygen species. Raj 3077 had stronger malate efflux and ALMT gene expression than Raj 4120. The root length of Raj 3077 seedlings was especially reduced by niflumic acid, an anion channel inhibitor, suggesting that malate detoxification is needed for root Al-resistance. Al-induced antioxidant defense and external malate detoxifying mechanisms help Raj 3077 cope with Al toxicity.
<figure><img src="image_181.png" /></figure>

### S.73.5 Diversity in tree hydraulic drought tolerance promotes temporal stability in forests

Raúl García-Valdés¹, José V. Roces-Díaz²,³,⁴, Miquel de Cáceres², Adrià Descals², Pilar Hurtado², Francisco Lloret²,⁵, Josep Maria Espelta², José Manuel Álvarez-Martínez⁶, Enric Batllori Presas⁷, Jordi Martínez-Vilalta²,⁵

1 Department of Biology, Geology, Physics and Inorganic Chemistry, School of Experimental Sciences and Technology, Rey Juan Carlos University, Móstoles, Madrid, Spain. 2 CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain. 3 Smart-Forests Research Group, Department of Organisms and Systems Biology, University of Oviedo, Mieres, España. 4. Biodiversity Research Institute IMIB, Spanish Research Council CSIC - University of Oviedo - Principado de Asturias, Mieres, Spain. 5 Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain. 6 Environmental Hydraulics Institute "IH Cantabria", University of Cantabria, PCTCAN, Santander, Spain. 7. Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.

Forest biomass productivity is essential for climate functioning and for providing other services to humankind. This productivity, however, is not constant, and it fluctuates between years due to variations in climate and the intrinsic characteristics of tree communities. At the same time, climate change is rising temperatures and climate variability around the World, increasing forest vulnerability to drought, and compromising the stability of forest functioning and services. It is therefore important to understand what factors drive the stability in forest productivity. We explored how tree community characteristics (local climate, vegetation structure and drought-related traits) affected the stability of 40k permanent forest plots across Spain. We used two decades of productivity-related satellite indices (NDVI and EVI) for measuring forest productivity stability, and stand-level data derived from the Spanish National Forest Inventory for measuring tree community structure (maturity and tree density) and mean and diversity of hydraulic drought tolerance traits (P50 and HSM). We found that there are complex interactions determining the patterns of stability, including direct and indirect effects of environmental variables, vegetation structure and tree species

drought adaptations. Forests showed higher stability with higher water availability, its stability in time, stand development and density of trees. We also found solid evidence that tree community diversity in hydraulic drought tolerance favoured stability. Results indicated that this diversity influences both, the mean of productivity (positively) and its standard deviation (negatively). Mean drought tolerance at the community level showed a less clear (but mostly negative) effect on stability. These results suggest that drought-related functional diversification would be a good management strategy to secure the stable provision of forest ecosystem services, especially under increasing variability in climate and intensity of droughts.

### S.73.6 Adapting to Compound Climate Stresses: lessons from two extremophytes

Isabel Johnson¹, Pramod Pantha¹, Kieu Tran¹, Richard Garcia¹, Maheshi Dassanayake¹

1 Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA

Agriculture faces increasing challenges from climate change, introducing complex stressors that reduce crop yields. Rising sea levels and prolonged droughts drive reliance on salt-contaminated water for irrigation. Additionally, extensive use of synthetic fertilizers elevates CO2 emissions and risks depleting non-renewable nutrients like phosphorus. As low-nutrient and high-salt soils become more common, these stresses frequently co-occur, complicating crop responses. When crops face combined stressors, their responses are often integrated rather than additive, presenting a novel challenge. Most stress experiments focus on single variables, leaving the effects of combined stresses largely unexplored. Therefore, developing solutions based on plant biology and genetics to design stress-resilient crops is increasingly important. Extremophytes, wild plants adapted to multiple environmental stresses, can provide insights into enhancing resilient crop growth. Schrenkiella parvula and Eutrema salsugineum are extremophyte models in the Brassicaceae family related to Arabidopsis thaliana. Their reference genomes were recently updated with chromosome-level assemblies. We
examined genomic, transcriptomic, metabolic, io-
nomic, and physiological responses of these two
extremophytes to compare their potential adap-
tive mechanisms in response to high salt and other
stresses. S. parvula often adjusted its root architec-
ture in response to single and compound stress-
es, while E. salsugineum showed minimal change
in primary root growth under similar stresses, in-
dicating physiological and genetic diversity within
extremophytes in the same family. S. parvula shows
stress-ready transcriptomes, while E. salsugineum
shows stress-ready metabolomes under salt expo-
sure. Additionally, our results identified several anti-

oxidant and nutrient recycling pathways active un-
der stress conditions in each species. These studies
in extremophytes suggest how key genes in stress
response pathways may function differently pro-
moting stress-resilient traits, synchronized across
developmental stages and tissues, distinguishing
extremophytes from stress-sensitive plants. Under-
standing the genetic mechanisms of these adap-
tive traits can significantly influence current and
future crop development strategies, with extrem-
ophytes offering a valuable genetic resource for
transformative crop design.

**S.74 ADVANCES IN PHYLOGENOMICS AND**
**SYSTEMATICS OF THE BRASSICACEAE. SESSION 1**

**S.74.1 The Brassicaceae then**
**and now -Advancements in**
**the past two decades**

Ihsan A. Al-Shehbaz¹

1 Plant Science Department, Missouri Botanical Garden, St. Louis, USA

It is generally agreed that the systematic and phylo-
genetic relationship within the mustard family (Brassi-
caceae or Cruciferae) is one of the best known among
all of the medium- and large-sized families of vascu-
lar plants. One of its species, *Arabidopsis thaliana*, be-
came the model organism of flowering plants about
two decades before it entire genome was sequenced
in December 2000. The most rewarding developments
in systematic botany started when a handful of Euro-
pean and American geneticists, together with their
students and others, focused from early to middle
1990's on the study of variation of a single chloroplast
gene (e.g., *rbcl*), chloroplast restriction-site variation,
or nuclear ITS in several species of a given genus or
several genera and assessed the phylogenetic impli-
cations of their data on systematic relationships and
character evolution. Those pioneering studies led in
2006 to the first phylogenetic tribal classification of the
Brassicaceae based on the single chloroplast genes
*ndhF*, in which 25 monophyletic tribes were recognized
based on a sample of 113 species in 101 genera. That
study, together with a global phylogeny of the family
based on the internal transcribed spacer (ITS), were
the foundation on which based are subsequent stud-
ies in the following 17 years that led to the most robust

and best available classification of the family using
thousands of genes. After 57 years of research on the
Brassicaceae, I summarize the major advancement
in the phylogenetics and systematic relationships of
the family within the past few decades. Brief compar-
isons of the limits of tribes, genera, and species be-
tween what was then and now are presented. Finally,
a handful of features that apparently evolved once in
the history of the family as we know it now.

**S.74.2 Resolving the**
**evolutionary history**
**of Arabideae using**
**phylogenetic placement**

Nora Walden¹, Christiane Kiefer, Marcus A. Koch

1 Department of Biodiversity and Plant Systematics, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany

The Arabideae represent the largest Brassicaceae tribe
with ~550 species in 18 genera, among them epon-
ymous *Arabis* and the large genus *Draba* with over
400 species. Polyploidy is prevalent in the tribe, with
ploidy levels up to hexadecaploid, and hybridization
is hypothesized to be common. Previous phylogenetic
studies have identified larger clades consistently, but
failed to provide resolution at the species level, in part
likely due to the presence of paralogs remaining from
past whole-genome duplications (WGDs) and hybrid-
<figure><img src="image_182.png" /></figure>

izations. We have developed a concept and workflow to infer polyploidization status from target enrichment data and reconstruct the evolutionary history of the taxa of interest using evolutionary placement of paralogs into a diploid reference tree. This method allows us to use information from paralogs despite multiple rounds of WGD and hybridization. Our results provide a solid backbone phylogeny for the Arabideae and pinpoint the ancestral lineages involved in past hybridizations. Within *Draba*, we found strong evidence that one of three main evolutionary lineages originated from hybridization between the other two lineages, with subsequent hybridizations giving rise to further subclades. In total we identified 68% of our samples as ancient polyploids and clustered them in over 40 clades with different patterns of paralog placement, suggesting independent or additional WGDs and hybridization events. Our study highlights the need for novel approaches to phylogenomics in clades with complex evolutionary histories.

### S.74.3 Exploring massive parallel evolution towards derived woodiness in the Brassicaceae

Kasper P. Hendriks¹,², Ihsan A. Al-Shehbaz³, Dmitry A. German⁴, C. Donovan Bailey⁵, Andreas Franzke⁶, Christiane Kiefer⁷, Marit Kuijt¹, Marcus A. Koch⁶, Martin A. Lysak⁸, Sander van Zon¹, Alexandre R. Zuntini⁹, Klaus Mummenhoff², Frederic Lens¹

1 Functional Traits, Naturalis Biodiversity Center, Leiden, The Netherlands. 2 Department of Biology, Botany, University of Osnabrück, Osnabrück, Germany. 3 Missouri Botanical Garden, St. Louis, USA. 4 South-Siberian Botanical Garden, Altai State University, Barnaul, Russia. 5 Department of Biology, New Mexico State University, Las Cruces, USA. 6 Heidelberg Botanic Garden, Heidelberg University, Heidelberg, Germany. 7 Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany. 8 CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic. 9 Royal Botanic Gardens, Kew, Richmond, UK

Flowering plants are characterized by a great variation in woody and non-woody (i.e., herbaceous) growth forms. The first flowering plants were woody, but many lineages evolved into herbaceous species. Interestingly, roughly 700 lineages turned back towards a state of phylogenetically derived woodiness. This remarkable case of massive convergent evolution has baffled scientists

since Darwin. Recent studies suggest drought as a main driving force, leading to a 'drought hypothesis'. We study the mustard family (Brassicaceae; ~4,000 species), which alone represents one out of seven of all woodiness shifts in flowering plants, making it the perfect model family to understand woodiness evolution. We recently developed a protocol to sequence >1,000 nuclear genes from herbarium specimens, allowing the reconstruction of a robust, time-calibrated Brassicaceae Tree of Life (BrassiToL). This phylogenetic framework will be essential to identify all ~100 woodiness shifts, thereby generating a powerful framework to test for an evolutionary link between woodiness and the environment. Here, we present our initial results, including a robust BrassiToL of over half the family's species, with a focus towards 'woody tribes' like Anastatiaceae, Heliophileae, and Lepidieae. Our first analyses of woodiness evolution suggest that drought is correlated with woodiness in at least several of the family's tribes, including Brassiceae and Alysseae. However, we found other factors to also correlate with woodiness, including UV intensity (Arabideae, Brassiceae, Thelypodieae) and aseasonality (Alysseae, Descurainieae, Erysimeae). In the face of global warming and periods of prolonged drought, understanding how plants cope with drought is essential, warranting a thorough assessment of the drought hypothesis.

### S.74.4 Eco-physiological features of C3-C4 Moricandia african clade: a range of within-individual phenotypic plasticities

Cristina Armas¹, Adela González-Megías², Francisco Perfectti², Luis Navarro³, Eduardo Narbona⁴, José M. Gómez¹,²

1 Estación Experimental de Zonas Áridas (EEZA-CSIC), Almería, Spain. 2 Universidad de Granada, Granada, Spain. 3 Universidad de Vigo, Vigo, Spain. 4 Universidad Pablo de Olavide, Sevilla, Spain

The majority of plant species on Earth employ C3 photosynthesis. However, more than a quarter of the assimilated CO2 by C3 species can be lost later to photorespiration, which is exacerbated in hot and arid conditions. In response, some plant lineages have evolved carbon concentrating mechanisms to improve net carbon assimilation, either re-assimilating the CO2 released by photorespiration (the uncommon C3-C4 intermediates) or directly inhibiting it (C4 species). There are no