tion. Analysis of volatile compound emitted by *D. stramonium*, showed that native plants produce a greater number of volatile compounds than non-native plants. Expression of gene *TPS10*, involved in the synthesis of volatile compounds, is higher in artificially damaged plants relative to control plants, and higher in native population and non-native populations. Overall, results suggest quantitative and qualitative change in defense traits between non-native population of *D. stramonium* but most changes are at the population level.

## S.227.6 Understanding how to a plague moves: The analysis of the expansion of Cactorum cactorum

Guadalupe Andraca-Gómez¹, Juan Fornoni¹

1 Universidad Nacional Autónoma de México; México City. Mexico

Human activities such as transport, trade and biological control practices have led to the movement

of different species, beyond their native distribution regions. Cactorum cactorum is a moth of Argentine origin, which feeds on plants of the genus Opuntia and was introduced for control. After its introduction in the Caribbean, it is considered an invasive species since it has spread to several Islands of the Caribbean, Mexico and the United States. Given the ecological and economic implications that its expansion implies, it is important to know the factors that favor and limit their dispersion. For this purpose, we asked, which environmental factors are correlated with the gene flow and population structure in the native and invaded area? In the invaded area it is observed that trade and hurricanes have promoted gene flow. On the other hand, factors such as seasonality and soil types affect the genetic structure in the native area of C. cactorum. The results show a change in the evolutionary processes affecting native and introduced populations to the extent that the incidence of hurricanes in the Atlantic and the Caribbean promote the expansion and re-entry in Mexico. Given high diversity of Opuntia in Mexico that can constitute potential host plants for C. cactorum, it is relevant the ongoing genetic and ecological monitoring

## S.228 TAXONOMY AS OPEN SCIENCE: TOOL SUPPORT TO FACILITATE DATA USE FOR HANDS-ON PRACTITIONERS

### S.228.1 Horama ID – making image classification models for species identification accessible to end-users

Alexander N. Schmidt-Lebuhn¹, Pete Thrall²

1 Centre for Australian National Biodiversity Research (a joint venture of Parks Australia and CSIRO), Canberra, Australia. 2 CSIRO, Canberra, Australia

Computer vision (CV) has matured as a mobile and user-friendly species identification tool, as demonstrated by apps such as iNaturalist or PlantSnap, which are aimed at the nature-enthusiastic public. However, the CV models of such apps cover taxonomic diversity opportunistically, based on what user-contributed images happened to be available

for training the model, as opposed to comprehensive coverage of a taxonomic group. Their scope is primarily the overall appearance of complete, living specimens in their natural environment. If CV is to become the next generation identification tool in taxonomy, field biology, and collection curation, biologists will have to be able to easily train, deploy, and use CV models for anything from dried fruits on a herbarium specimen to pinned insects of their study groups. Specimen collections are increasingly being imaged, and commercial cloud services allow users without expertise in AI research to train models. The main remaining bottleneck is getting species identification models into the hands of end-users. We present Horama ID, a system for the storage and deployment of image classification models for species identification. It consists of a server where contributing taxonomists can upload the model, metadata such as its title and description, who created it, acknowl-
<figure><img src="image_530.png" /></figure>

edgements, and a title image, as well as a table of
species profiles including profile images and external
weblinks, e.g., to eFlora profiles. The Horama app dis-
plays the list of models available on the server and
allows the user to download them individually and
switch between them. The camera page of the app
displays live updates of identification estimates. The
user can tap suggested names to see species pro-
files and compare them against the specimen. Hora-
ma ID gives taxonomists the opportunity to develop
CV models as part of their studies in the confidence
that they can become available to end-users.

S.228.2 ParseGBIF: data and
an interactive database for
visualising and prioritising
plant occurrence data

Alexandre Monro¹, Pablo Hendrigo Alves
de Melo², Nadia Bystriakova³

1. Royal Botanic Gardens, Kew, Richmond, London, UK, a.monro@kew.org. 2 Instituto Federal de Educação, Ciência e Tecnologia de Minas Gerais, Campus Avançado Piumhi, Brazil. 3 The Natural History Museum, Cromwell Road, London, UK

Global and national initiatives to halt the loss of plant
diversity require adequate knowledge of species and
their occurrences. Such knowledge can be currently
characterised as poor and very uneven (Oliver et al.
2020). For example, in GBIF the plant diversity of the
Amazon Forest biodiversity hotspot is documented
by an average of 10 to 14² occurrence records per
100 km². In contrast, the Mesoamerican biodiversity
hotspot in Costa Rica is documented by 10,539 re-
cords per 100 km² (GBIF). Despite this, there are few
tools to visualize knowledge gaps or to prioritize how
they should be filled. We have developed such a tool,
Prioritization Resource for Information-driven Spe-
cies Monitoring (PRISM) for doing so at the regional,
national, or subnational level. PRISM aims to support
the prioritization of areas for data acquisition based
on local priorities. To do so we have, 1) developed a
workflow, ParseGBIF (Melo et al. 2023), to assemble a
baseline of occurrence records, 2) used the baseline
to characterize sample effort and gaps in occur-
rence data at high resolution, and 3) overlayed these
with key biodiversity, conservation and ecosystem
services layers to support the prioritization of areas
for data acquisition, at the regional, national, or sub-
national level through an interactive database.

References: Oliver et al. (2021) Global and nation-
al trends, gaps, and opportunities in document-
ing and monitoring species distributions. https://
doi.org/10.1371/journal.pbio.3001336. GBIF, biological
collections occurrence data, accessed January 16
2023. Hendrigo Alves de Melo et al. (2023). https://
doi.org/10.21203/rs.3.rs-3579370/v1

S.228.3 Improving access to
biodiversity data: leveraging
digital tools and global
information standards

Celia C. Aceae¹

1 School of Biological Sciences, University of Edinburgh, Edinburgh, UK

Herbaria represent vast repositories of data that
have the potential to contribute to research across
biological disciplines. The value of herbaria and the
data of the specimens within depends largely on the
accessibility and quality of this information. As collec-
tions become more widely available through large-
scale digitisation initiatives, it is integral to develop
tools that can help researchers and curators access,
review, assess, and annotate specimen data and
related information with ease. Additionally, as spec-
imens are included in nomenclatural and taxonom-
ic events, digitised collections and data repositories
must reflect these changes rapidly to ensure the
most accurate distribution of information. Here, we
trialled the tool Echinopscis, an "extensible notebook
for open science on specimens" (Nicolson & Lucas,
2022). Echinopscis has provided researchers and cu-
rators with a new and effective way to access spec-
imen determinations within other institutions across
the globe and has been used to facilitate note-taking
and data tracking. Curators of herbaria are limited by
resource availability and level of training, meaning
that curation standards vary within herbaria and dif-
fer greatly between herbaria. Institutions, researchers,
curators, and collectors have different methods of re-
cording data in the field, in the herbarium, and in the
digitisation process. Small variations in the presenta-
tion of data can have vast impacts on how data is
sorted and accessed digitally. In a time marked by
worldwide open access information sharing, there
is a vast need for more global standards in herbari-
um curation. Here, we present recommendations for
global standards in data recording and identify op-
portunities for the development of new tools to assist
and facilitate the curation process within herbaria.
<figure><img src="image_531.png" /></figure>

## S.228.4 New advances in the development of echinopscis, an extensible notebook for open science on specimens

Nicky Nicolson¹, Eve J. Lucas¹

1 Royal Botanic Gardens, Kew, UK

Botany can claim to have led the way in the mobilisation of specimen metadata through digitisation. Botanical research groups also were central in the development of e-taxonomic systems to apply this digital information in networked research activities. With the subsequent growth of the open science movement, many generic research tools and working practices have become available. We highlight tools and platforms which can be adapted for use to realise the vision of e-taxonomy and to enable researchers to easily access and use the wealth of data that is now available online. The "echinopscis" project is an experiment in creating an extensible notebook for open science on specimens, built on the generic note-taking software Obsidian. In contrast to early centralised e-taxonomic systems it operates on a local set of files stored in plain text (Markdown) format, enabling the user to have confidence about long term access to their data. It facilitates access to many of the components of the digital extended specimen, including literature, nomenclature, taxonomy, specimen metadata, images, and descriptive data. These data can be further contextualised through access to information stored in Wikidata, which supplies identifier mappings and can act as a broker between different information systems. The use of open data formats and generic data reconciliation standards should allow wider participation in the project and help to cement open science principles in the process of botanical taxonomy.

## S.228.5 The digital extended specimen network: from manual links to machine-action accelerating network generation

Jutta Buschbom¹,², James A. Macklin³,
Richard K. Rabeler⁴, Katelin Pearson⁵,⁶

1 Natural History Museum, London, UK. 2 Statistical Genetics, Ahrensburg, DE. 3 Agriculture and Agri-Food Canada, Ottawa, Canada. 4 University of Michigan, Ann Arbor, USA. 5 Arizona State University, Tempe, USA. 6 Integrated Digitized Biocollections, Gainesville, USA

With advancing digitization of natural science specimens, e.g. preserved in herbaria and paleobotany collections, bio- and geodiversity researchers are increasingly working with digital representations of collection specimens and related digital-born data. Dedicated and enthusiastic, they are embracing and developing digital tools and platforms to infer novel discoveries and support conservation decisions to address the biodiversity crisis. Research that is meeting today's questions and challenges increasingly relies on high-quality, multidimensional datasets that are seamlessly integrated across sources and data-types. Accordingly, on-site digital infrastructures are currently more and more integrated with online resources and functionality. These developments have led to the concept of the Digital Extended Specimen (DES), which describes how a diversity of Findable, Accessible, Interoperable and Reusable (FAIR) data from disparate sources can be linked and integrated into analysis pipelines. Recognizing that large-scale, fair and equitable technical linking needs to be community-driven and requires social connections, networks of trust, and community acceptance, the International Partners for the DES (IPDES) were formed. Since 2020, the informal group brings together individual scientists, representatives of international, national and regional organizations, and stakeholders from different backgrounds. It provides a forum for exchange and coordination to foster and expand on community-driven successes to connect people, data, tools, and working practices. We present insights from a community workshop in 2023 that explored data linking, and we reflect on the rapid developments over the past months towards linked resources. The workshop revealed several difficulties in extending existing natural history specimens, including lack of automation and lack of pertinent data. One year later, we address the questions: where are we now? Do we have everything we need, or are there gaps? Importantly, do we address the concerns and expectations of both the communities of tool and infrastructure providers and end users?

## S.229 UNDERSTANDING FLORAL EVOLUTION
# ALONG MULTIPLE DIMENSIONS: EMERGING PATTERNS OF MORPHOLOGICAL, SCENT, AND COLOR VARIATION. SESSION 2

## S.229.1 Pollen release dynamics in morphologically distinct buzz-pollinated Melastomataceae flowers

Benjamin S. Lazarus¹, Ash Kerber², César Arvelos³, Fabian Michelangeli⁴, Agnes S. Dellinger¹

1 Department für Botanik und Biodiversität, Universität Wien, Wien, Österreichische. 2 University of Colorado - Boulder, Department of Ecology and Evolutionary Biology, Boulder, Colorado, USA. 3 Programa de Pós - Graduação em Ecologia, Conservação e Biodiversidade, Universidade Feredal de Uberlândia, Uberlândia, Minas Gerais, Brazil. 4 Instituto of Systematic Botany, New York Botanical Garden, New York City, New York, USA.

Flowers that are buzz-pollinated have evolved restricted, poricidal anthers that are most effectively pollinated by bees rapidly vibrating the stamens to extract pollen. This functionally specialized pollination strategy has evolved repeatedly in approximately 8% of angiosperms, and dominates in the plant family Melastomataceae, with around 96% of species exhibiting buzz pollination. Within Melastomataceae, a vast diversity of anther shapes and configurations have emerged and have been equated to an 'adaptive plateau' of morphologically successful phenotypes. In this study, we explore the biomechanics of different anther structures and their effects on pollen release dynamics. Using CT scans and artificial buzzing experiments of morphologically distinct Melastomataceae species, we relate vibration parameters (frequency, amplitude, and number of pulses) and anther structure to pollen release rates. We present results from convergent and divergent anther types found in different genera across three different Melastomataceae communities. We then interpret these results in their pollination-ecological context, i.e., whether Melastomataceae species visited by a larger diversity of bee species also show high pollen release rates across a larger range of vibration parameters. This work is

done with the aim of contributing to the field's understanding of the evolution and functioning of stamen trait diversity and subniche partitioning within the buzz-pollination syndrome, as well as to pinpoint potential evolutionary trajectories towards convergent or divergent floral phenotypes.

## S.229.2 Flower trait evolution and pollination sharing in a community context

Rocío Pérez-Barrales¹

1 Botany Department, University of Granada, Spain.

Pollination involves the transfer of pollen from anthers to stigmas. Indeed, pollination is a "messy" process shaped by the fit between flowers and pollinators, the contact with reproductive organs along the body of pollinators, pollinator preferences, and the plant's breeding system. In addition, pollination interactions are often generalized, leading co-flowering congeners to share pollinators, creating selective pressures based on reproductive costs. If costly, the evolutionary consequences of pollinator sharing should be reflected in patterns of variation in reproductive organs to reduce interspecific pollination and reproductive interference. Here, I investigate variation in pollinator fit, pollen pick-up, and deposition in allopatric and sympatric populations of *Linum suffruticosum* with other *Linum* species. The study aims to understand if floral variation can be attributed to local patterns of pollinator sharing, reducing interspecific pollen transfer. Observations in different localities, floral measurements to measure morphological overlap between species, and quantitative analyses of reproductive costs through interspecific hand pollinations were conducted. Results revealed that the size and identity of the most important pollinator explained floral trait variations. The morphological overlap of *L. suffruticosum* flowers with co-flowering species varied depending on the identity of the co-flowering species. While post-pollination incompatibility maintains reproductive isolation, conspecific pollen-tube formation decreased after heterospecific pollination. In co-flowering sites, conspecific pollen-tube formation was lower than in
<figure><img src="image_532.png" /></figure>

single-species localities. Overall, the results suggest that trait variation in *L. suffruticosum* corresponds to the most important local pollinator, and incomplete pollinator partitioning may lead to interspecific pollination with associated reproductive costs. These costs may drive selection favoring reduced morphological overlap with co-flowering congeners, potentially leading to the evolution of pollination ecotypes.

### S.229.3 Floral allometry and its relationship with pollinators along an altitudinal gradient of the tropical Andes of Bolivia

Sissi Lozada-Gobilard¹,², Øystein H. Opedal¹

1 Biodiversity Unit, Department of Biology Lund University, Sweden. 2 Instituto de Ecología, Universidad Mayor de San Andrés, La Paz, Bolivia.

Flower traits have been shown to be related to breeding systems (outcrossing vs. selfing), pollinators and can vary along environmental gradients. Environmental variation along altitudinal gradients is commonly associated with changes in the diversity of plants and animals, making them ideal systems to study variation in flower traits and its relationship with pollinators. We measured flower traits of 20 plant species and observed their pollinators (flower visitors that touched reproductive parts of the flower) along an altitudinal gradient (1000-4500m) in the tropical Andes of Bolivia. Flower traits included flower size, entrance diameter, flower length and anther-stigma distance. In particular, we compared allometries of stigma-anther height and flower size traits along the gradient. In this study we test the hypothesis that anther-stigma correlations is stronger at higher altitudes, assuming that at higher altitudes the conditions are harder, pollination is less reliable and therefore selfing plants species would be more common. We tested whether allometric slopes for fit traits (anther-stigma height) differ from those for flower size traits and among pollination systems. We expect to find a shallower allometric slope for fit traits than size traits. Additionally, we tested whether anther-stigma height correlations are related to more generalist plant species or a particular guild of pollinators.

### S.229.4 The importance of your neighbors: co-

### flowering community effects on pollination and reproductive success of deceptive orchids

Yedra García¹, Michael Hedrén¹, Magne Friberg¹, Øystein H. Opedal¹

1 Biology Department, Lund University, Lund, Sweden.

Interactions for pollinators among co-flowering species are common and can modify plant reproductive success and ultimately natural selection on floral traits. However, studies considering the effects of the whole co-flowering community are still rare. Food-deceptive orchids provide suitable models to test for community effects on plant fitness as they often depend on rewarding co-flowering species to attract pollinators. Novel statistical approaches such as hierarchical latent-variable joint models now allow testing the influence of multiple co-flowering species on plant reproductive success. Here, we used two food-deceptive orchids *Dactylorhiza majalis* subsp. *lapponica* and *D. majalis* subsp. *majalis* to address the effects of the co-flowering community on pollination and plant reproductive fitness. We implemented the Hierarchical Modelling of Species Communities (HMSC) framework by fitting hierarchical latent-variable joint models with relative pollination success and fruit set as response variables. Together with phenotypic traits, we included the animal-pollinated co-flowering species in the community of each orchid as model predictor by using a reduced-rank regression approach in HMSC. Our results revealed that the animal-pollinated co-flowering community affected both pollination success and reproductive fitness via fruit set. Moreover, for *D. lapponica*, we found that the effect of animal-pollinated co-flowering species was strong even after accounting for effects of non-animal pollinated species in the community. By using a reducing-rank regression approach within the HMSC framework, we yielded new insights on the biotic factors influencing pollination and reproductive success of deceptive pollinated species. This approach can be extended to other pollination systems and plant communities and highlights the importance of considering the whole co-flowering community to understand the ecology and evolution of flowering plants in multispecies communities.

### S.229.5 Flower size, thermal plasticity and local
<figure><img src="image_533.png" /></figure>

adaptation under climate
change

Andrés Romero-Bravo¹, Maria C. Castellanos¹, Marko Hyvärinen³, Susanna Koivusaari²,³, Aino Kotilainen², Martti Levo², Anniina Mattila³, Charlotte Møller³, Øystein H. Opedal⁴, Laura Pietikäinen³, Maria Hälfors²,⁵

1 University of Sussex, Brighton, UK. 2 University of Helsinki, Helsinki, Finland. 3 Finnish Museum of Natural History, Helsinki, Finland. 4 Lund University, Lund, Sweden. 5 Finnish Environment Institute (Syke), Helsinki, Finland.

Increasing average temperatures as well as more frequent extreme weather events caused by climate change are likely to affect plant-pollinator interactions around the globe. The ability of plants to adapt their reproductive strategies to new environmental conditions is crucial for their survival. Temperature-induced changes in the floral phenotype might negatively affect visitation rates and potentially hinder plant sexual reproduction and reduce fitness. At the same time, phenotypic plasticity may improve plant fitness under fluctuating environments. We used *Hypericum perforatum* to assess the effect of temperature on floral and flowering traits using a common garden full factorial setup. Contemporary and historical seed accessions, collected across the native distribution of the species, were grown under four temperature treatments. We tested for differences in population-level floral plasticity between temporal (ancestors vs. descendants) and geographical (trailing, core, and leading part of the distribution) origins to reveal potential changes in plasticity over the last decades and how these vary across space. We compared local adaptation of ancestral and descendant populations in a reciprocal transplant experiment across the European native range of the species. Our results show that higher temperatures are associated with a reduction in flower size and flower display and an earlier onset of flowering. Ancestral and descendant populations differed in flower thermal plasticity, which may have played an adaptive role over the last decades. Additionally, a reduction in fitness linked to a smaller flower size, display or earlier flowering onset could highlight detrimental effects of higher temperatures on plant sexual reproduction. Lastly, in our reciprocal transplant experiment, individuals from descendant populations flowered earlier than their ancestral counterparts, indicating potential rapid adaptive evolution to a warmer climate. Understanding evolution of thermal plasticity

and floral adaptation to higher temperatures will im-
prove predictions on how plant-pollinator interactions
may respond to climate change.

S.229.6 Floral trait integration and potential for reproductive interference in North American Lobelia (Campanulaceae)

Andrea Case¹, Svea Hall¹, Eli Graber²,
Cooper Murphy², Lynda Delph²,
Grant Godden³, Nico Cellinese³, Chris
Blackwood¹,⁴

1 Department of Plant Biology, Michigan State Uni-
versity, East Lansing, Michigan, USA. 2 Department
of Biology, Indiana University, Bloomington, Indiana,
USA. 3 Florida Natural History Museum, University of
Florida, Gainesville, Florida, USA. 4 Department of
Plant, Soil, and Microbial Sciences, Michigan State
University, East Lansing, Michigan, USA.

Tight integration of floral traits may constrain floral di-
versity among closely related species and influence
mechanisms of pre-mating reproductive isolation
as well as the potential for reproductive interference
when close relatives co-occur. Here, we present a
detailed analysis of floral morphology in *Lobelia* sect.
*Lobelia* (Campanulaceae). This monophyletic clade
comprises 25 eastern North American species with
a diversity of breeding systems, from obligate in-
breeding to bee and hummingbird pollination to gy-
nodioecy. Even though *Lobelia* sect. *Lobelia* species
are phenotypically and ecologically similar, largely
cross-compatible in the greenhouse, and frequent-
ly sympatric, hybrids are rarely observed in the wild.
We measured 40+ morphometric characters on pre-
served flowers from across the ranges of 19 species,
including samples from allopatric and sympatric
populations and greenhouse-grown hybrids. A single
principal component explained more than half of the
variation in overall flower size and showed strong phy-
logenetic compared to geographic structure. Species
exhibit distinct floral forms that fall along three contin-
uous axes of floral shape: shorter, wide corolla tubes
accommodating bumblebee access; long, narrow
tubes associated with hummingbird pollination; con-
tinuous length variation with medium-sized tubes, with
the smallest borne on selfing species and larger flow-
ers associated with visits by small bees and butterflies.
While the sex organs of all species show the form typ-
ical of the *Lobelia* "pollen pump," their lengths and an-
<figure><img src="image_534.png" /></figure>

gles within the flower differ in ways that should affect
the likelihood of interspecific pollen transfer. Individual
metrics of size and shape show different patterns of
inheritance in hybrids, with most matching one of the

parents and only some traits showing intermediate
values. We interpret these patterns in light of effects
on reproductive dynamics, isolation and interference
where these congeners occur in sympatry.

S.230 BENEFICIAL PLANT-MICROBE
INTERACTIONS. SESSION 3

S.230.1 Dynamics of
microbial communities
associated with Pisum
spp. (Fabaceae) across
plant growth stages and
microhabitats

Victor Angot¹, Yanis Bouchenak-Khelladi¹

1 UMR Agroécologie, Université de Bourgogne INRAE,
Dijon, France.

The discovery of the holobiont in plants (host plant-mi-
croorganism association), particularly in angiosperms
have revolutionized our understanding of the effects
on the physiology and ecology of associated plants.
The plant-microorganism interaction is governed by a
'chemical dialogue' via the production of exudates by
the plant which selects and recruits bacterial commu-
nities which, in return, produce metabolites which facil-
itate the acquisition of nutrients and help promote the
growth of the host plant. Symbiotic relationships be-
tween plants and microorganisms are the most docu-
mented, such as *Rhizobia* strains associated with root
nodulating legumes that facilitate N uptake. Beyond
these associations, non-symbiotic bacteria also im-
pact their host. Significant gaps persist in understand-
ing these complex microbial associations and require
holistic approaches at different temporal and spatial
scales. In this study, we conducted a greenhouse ex-
periment to characterize the microbial communities
associated with *Pisum* throughout its developmental
cycle and in four compartments or microhabitats pro-
vided by the host plant. Microbiomes from four com-
partments of 144 plants from four different *Pisum* gen-
otypes (*Pisum fulvum*, *P. sativum* subsp. *abyssinicum*, *P.
sativum* subsp. *elatius* and *P. sativum* subsp. *sativum*)
were sampled at three distinct developmental stag-
es, representing a total of 456 microbial communities.
These microbiomes were analyzed using full 16S rRNA
gene PACBIO sequencing and phylogenetically-cor-

rected statistical analyses. Our results suggest that
the plant-associated microbiome composition and
structure evolved throughout the plant's developmen-
tal cycle, likely in response to differential nitrogen and
carbon allocations during vegetative, flowering, and
seed-filling stages. The different microhabitats offered
by the plant acted as ecological filters, influencing the
composition of bacterial communities. Finally, bacteri-
al communities associated with peas exhibited differ-
ences based on the genotype of the host plant. These
findings enhance our understanding of the dynamics
of bacterial communities and the host's influence in
shaping this process.

S.230.2 Whole-soil microbial
communities from shaded
coffee plantations and
montane forest fragments
offer similar benefits to
coffee and

Camila Pizano¹, Scott A. Mangan²

1Department of Biology, Lake Forest College, Lake For-
est, Illinois USA. 2 Department of Biological Sciences,
Arkansas State University, Jonesboro, Arkansas, USA.

Soil microbial communities are among the most spe-
cies-rich components of terrestrial ecosystems and
can influence plant productivity and quality by estab-
lishing direct interactions with plant roots (pathogens,
parasites, root herbivores, mycorrhizae) and by locking
or liberating nutrients into the soil. However, agricultur-
al practices such as tillage and fertilization can reduce
soil community diversity in general, reduce mycorrhizal
inoculum potential, or modify the abundance of soil
microorganisms such as arbuscular mycorrhizal fun-
gi (AMF). In this study we exposed seedlings of coffee
(Coffea arabica), and three native shade tree species
(Albizia carbonaria, Cordia alliodora and Inga densiflo-
ra) to contrasting soil types and sterilized vs. whole-soil
<figure><img src="image_535.png" /></figure>

live microbial communities from long-term fertilized shaded coffee plantations and montane forest fragments in Colombia. Surprisingly, plants showed a limited response to contrasting soil types, but benefited from live soil microbial communities, and their growth differed across varied combinations of soil type and inoculum source. Fast-growing plant species (A. carbonaria and C. alliodora) benefited the most from inoculation with live soil organisms, but A. carbonaria benefited the most from soil microbes coming from shaded coffee plantations. In contrast, shade-tolerant species (C. arabica and I. densiflora) performed similarly across different live inoculum sources, but growth of I. densiflora with a live inoculum was higher in soils containing higher organic matter, and N and P contents. AMF colonization varied across species, being the lowest in C. arabica, but similarly high for plants inoculated with soils coming from shaded coffee plantations and forest fragments. These results suggest that agricultural systems that maintain intermediate plant diversity and employ low soil disturbance, despite fertilization, maintain soil microbial communities similar to those present in more diverse natural habitats.

### S.230.3 A small signal peptide modulates root hair growth in response to fungal ethylene emissions

Rafael Jorge León Morcillo¹, Jesús Leal-López¹, Alberto Férez-Gómez¹, Lidia LópezSrano¹, Edurne Baroja-Fernández², Samuel Gámez-Arcas³, Germán Tortosa⁴, Leonel E. López⁵, José Manuel Estevez⁵,⁶, Verónica G. Doblas¹, Laura Frías-España¹, María Dolores García-Pedrajas¹, Jorge Sarmiento-Villamil¹, Javier Pozueta-Romero¹

1 Institute for Mediterranean and Subtropical Horticulture "La Mayora", CSIC-UMA, Campus de Teatinos, Málaga, Spain. 2 Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, Mutiloabeti, Nafarroa, Spain. 3 Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas - Universidad de Sevilla, Sevilla, Spain. 4 Department of Soil and Plant Microbiology, Estación Experimental del Zaidín (CSIC), Granada, Spain. 5 Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires, Argentina. 6 Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile and ANID - Millen-

nium Science Initiative Program - Millennium Nucleus for the Development of Super Adaptable Plants, Santiago, Chile.

In nature, plants and microorganisms communicate with each other by exchanging different signaling compounds including volatile compounds (VCs), some of which have biostimulating properties. In Arabidopsis, VCs from the fungal phytopathogen Penicillium aurantiogriseum promote growth, photosynthesis and root hair (RH) proliferation and hyper-elongation through mechanisms involving ethylene, auxin and photosynthesis signaling. A striking alteration in the proteome of roots of fungal VC-treated plants involves strong up-regulation of RALF22. To test the possible involvement of the RALF22 in the fungal VC-promoted RH changes, we characterized the RH responses of ralf22 and fer-4 plants impaired in RALF22 and its receptor FERONIA to VCs emitted by P. aurantiogriseum. We found that these plants were unresponsive in terms of VC-promoted RH elongation and proliferation. Unlike in WT roots, fungal VCs did not enhance the transcript levels of RALF22 in roots of fer-4 and ethylene- and auxin- insensitive mutants, and those of RH-related, ethylene-responsive genes (e.g. RSL2, RSL4, RHD2, PRX1 and PRX44) in ralf22 and fer-4 roots. Finally, we identified ethylene as the bioactive fungal VC, as VCs of ΔefeA strains of P. aurantiogriseum cultures impaired in ethylene synthesis weakly promoted RH proliferation and elongation in exposed plants. Collectively, our results demonstrate that RALF22-FERONIA complex is a key determinant of the ethylene, auxin and photosynthesis signaling-mediated RH response to fungal ethylene emissions.

### S.230.4 The use of compost improves biodiversity in the bacterial community of the rhizosphere of tomato plants

Nadine De Biasio¹, Rosalba Cipriani¹, Giulia Ghirardelli¹, Tiziano Bonato², Werner Zanardi², Barbara Baldan¹, Sebastiano Nigris¹

1 Department of Biology, University of Padova, Padova, IT. 2 SESA spa, Este (PD), Italy.

Certain bacteria form symbiotic relationships with plant roots in the rhizosphere and on the rhizoplane and endosphere of the roots, leading to improved plant nutrient uptake, enhanced productivity, and resilience to abiotic stresses and pathogens. However, soil
biodiversity is nowadays endangered and reduced by modern agricultural practices, having a severe impact on soil structure and plant productivity. Soil microbiota is the source from which plants recruit bacteria species to interact with. A community of bacteria in the soil and the rhizosphere is necessary to allow correct plant nutrition, and development, and to help the plant to cope with environmental and biotic stresses. Among all the strategies to sustain soil biodiversity, biofertilizers, substances containing beneficial microorganisms that enhance plant health and growth, offer a potential remedy. Among these, compost, a product of controlled aerobic decomposition of organic materials carried out by microorganisms, stands as a promising solution. Recognized in agriculture for being rich in organic matter and nutrients, compost's unexplored potential as a microbial inoculum for enriching the soil and fostering plant health necessitates further investigation. This work revolves around the study of compost and its role as a source of beneficial microorganisms, aiming to elucidate its capacity to enrich microbial communities in soil and the rhizosphere. Additionally, the study seeks to isolate and characterize the culturable bacterial diversity within compost and assess its ability to promote plant growth. This research contributes to understanding sustainable agricultural practices and soil ecosystem health, aligning with the EU's 2030 sustainable development goals.

Recent research has shown that bioaugmentation of crops with halotolerant bacteria isolated from halophytic plants can alleviate salt stress and promote plant growth. *Halocnemum strobilaceum* is a widespread hyperhalophyte desert plant known for its antioxidant, antimicrobial, insecticidal and phytoremediation properties. However, it is critically endangered in Spain. Whereas most of the studies focus on rhizospheric bacteria, little is known about how endophytes help halophytes to cope with salt stress. In this work we study the diversity of endophytic bacteria of *Halocnemum strobilaceum* from arid areas of Murcia and Almeria, Spain. In total, 79 endophytic bacterial strains were isolated from the aerial parts of this halophytic plant on tryptic soy Agar supplemented with 0.5 M NaCl to ensure their salt tolerance. They show in vitro plant growth promoting (PGP) properties as phosphate solubilization, siderophore production, auxin IAA production, biofilm formation, and enzymatic activities as protease or cellulase. We also carried out 16S rRNA gene sequencing and found several isolates could be new potential species of Halomonas and Kushneria, a relatively novel and small genera. We selected three best strains based on their PGP properties and set up a greenhouse trial with *Medicago sativa* under 100mM NaCl salinity stress to test the consortia capacity in mitigating salt stress.

## S.230.5 Halocnemum strobilaceum as new source of potentially plant growth promoting endophytic bacteria

Romano-Rodríguez Elena¹, Flores-Duarte N.J.¹, Mateos-Naranjo Enrique¹, Navarro-Torre Salvadora², Rodríguez-Llorente Ignacio D.², Pajuelo Eloísa², Redondo-Gómez Susana¹

1 Department of Plant Biology and Ecology, Faculty of Biology, University of Seville, Seville, Spain. 2 Department of Microbiology, Faculty of Pharmacy, University of Seville, Seville, Spain.

In recent years, several efforts have been made to enhance the salt-tolerance of plants, as salinity stress is one of the major abiotic stresses threatening crop production in arid and semi-arid regions. Also, soil salinization is expected to increase due to climate change and increased irrigation practices.

## S.230.6 Defining a forest by the fungi: "mycorrhizal spillover" effects on nutrient cycles, soil microbiomes, and plant community dynamics

Christopher B. Blackwood¹,², Andrew C. Eagar¹, Princess H. Abu¹, Megan A. Brown¹, Sara M. Moledor¹, Kurt A. Smemo³, Richard P. Phillips⁴, Andrea L. Case¹

1 Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA. 2 Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, Michigan, USA. 3 Environmental Studies and Science Program, Skidmore College, Saratoga Springs, New York, USA. 4 Department of Biology, Indiana University, Bloomington, Indiana, USA.

Arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) tree species tend to differ across a multitude of
<figure><img src="image_536.png" /></figure>

traits beyond the structure of the root symbiosis, in-
cluding leaf and root chemistry, litter decomposability,
carbon allocation to mutualistic fungi, and protection
from root pathogens. Here we explore how, as foun-
dation species, the mycorrhizal type of dominant trees
also has a profound "mycorrhizal spillover" effect on
soil biogeochemistry and the soil microbiome, result-
ing in different stresses experienced by all members
of the plant community. We present evidence that,
compared to soil in forests dominated by ECM tree
species, soils in forests dominated by AM tree species
have increased soil mineral nutrient availability, great-
er abundance and diversity of plant pathogens and
AM fungi, and lower abundance and diversity of ECM

fungi. Although we discuss some context-dependency of these patterns, they seem to be consistent even across a continuous gradient of mycorrhizal dominance (i.e., 0 to 100% AM basal area), and for individual species (e.g., for AM plants surrounded by increasing dominance of ECM trees, and vice versa). Based on these patterns, we describe a new hypothesized framework of additive and interactive effects of mycorrhizal spillover. These mycorrhizal spillover effects shift the strength and direction of plant-soil feedback and conspecific density dependence in predictable ways, which has implications for our understanding of future plant community and evolutionary dynamics.

S.231 TROPICAL PLANT EVOLUTION ACROSS
SPATIAL AND TEMPORAL SCALES. SESSION 2

S.231.1 Do reticulate relationships between tropical trees drive diversification?

Rowan J. Schley¹, Alex D. Twyford²,³,
Flavia Pezzini³, Catherine Kidner²,³,
Rosalia Piñeiro⁴, Maria-Jose Endara⁵,
James Nicholls⁶, Kyle G. Dexter², R. Toby
Pennington¹,³

1 University of Exeter, UK. 2 University of Edinburgh, UK. 3Royal Botanic Garden, Edinburgh, UK. 4 University of A Coruña, Spain. 5 Universidad de Las Americas, Quito, Ecuador. 6 CSIRO, Canberra, Australia.

Radiations that generate species-rich clades are fun-
damental in the evolution of diversity. Hybridisation
can facilitate radiations through transfer of adaptive
variation, catalysing rapid divergence. Much of the
hyperdiverse neotropical tree flora was generated by
radiations, but the influence of hybridisation on their
evolution remains unexplored. Rainforest tree com-
munities are subject to relentless insect herbivory,
such that co-occurring tree species differ significantly
in herbivore defence chemistry, with 'rare' defences
most effectively overcoming local herbivores. Chem-
ical defences show evidence of divergent evolution
between sister species of *Inga*, a chemically diverse
genus of >300 rainforest trees that typifies rapid neo-
tropical tree radiations. Thus, here we ask whether

hybridisation catalysed the rapid radiation of *Inga*
through passage of 'rare' herbivore defence traits. We
use phylogenomic approaches to first understand
whether reticulation preceded rapid diversification in
*Inga*, and hence whether hybridisation may underlie
this radiation. Then, using whole-genome resequencing of >520 *Inga* accessions comprising >40 species, we ask whether hybridisation facilitates the transfer of linkage blocks containing 'rare' chemical defence loci between species. Overall, we aim to assess whether ecological divergence facilitated by transfer of adaptive variation through hybridisation helped to generate the unmatched diversity of rainforest trees.

S.231.2 Contrasting diversity and biogeographic patterns in the forest-savanna transitions of Africa.

Mathew Rees¹,², John L. Godlee¹, David J.
Harris², Casey M. Ryan¹, Kyle G. Dexter¹,²

1 University of Edinburgh, Edinburgh, UK. 2 Royal Botanic Garden Edinburgh, UK.

In tropical Africa, forests and savannas are the two
most widespread biomes and potentially represent al-
ternative stable states with a divergent species com-
position. Transition zones between the two biomes are
thought to be floristically impoverished, with fewer rep-
resentatives from each biome. Further, the evolutionary
<figure><img src="image_537.png" /></figure>

dimension of diversity has received limited attention, despite its importance for understanding the biogeographic history of biomes. Here, we quantified species richness and several measures of evolutionary diversity in 1º grid cells, using ca. 300,000 occurrence records of trees and shrubs combined with biome affiliation data for 3203 species. We found that assemblages in transition zones hold fewer woody species than assemblages in forest and savanna zones. However, transition zones hold more phylogenetic diversity than expected given their species richness, whether one considers forest and savanna assemblages separately or together. We also show that the Congo Basin forests have low levels of phylogenetic diversity, given the number of species, and highlight south-eastern African savannas as a centre of savanna woody species richness and phylogenetic diversity. Regions with high phylogenetic diversity, given the number of both forest and savanna species, were centred around the Dahomey Gap and Cameroon, mainly in transition zones. Overall, our study shows that even if floristically impoverished, transition zones hold unexpectedly high evolutionary diversity. This suggests that they are important centres of evolutionary innovation and diversification and/or serve as evolutionary crossroads, where lineages that diversified in contrasting environments coexist within a single area.

### S.231.3 Insight into biodiversity formation in Amazonia: phylogeny and evolution of the fern genus Adiantum

Chi-Chuan Chen¹, Samuli Lehtonen¹, Hanna Tuomisto¹,²

1 University of Turku, Turku, Finland. 2 Aarhus University, Aarhus, Denmark.

The tropics are home to high species diversity, but our understanding of the formation, evolution and distribution of that diversity is still limited. This hampers the targeting of conservation efforts, especially in such mega-diverse environments as Amazonia. Here we focus on unraveling the evolutionary diversification of the fern genus *Adiantum* in Amazonia. The genus has approximately 225 species distributed worldwide, and ecological inventories have found it to be one of the most abundant and diverse fern genera in Amazonian rain forests, making it an ideal example group. However, the species delimitations, phylogenetic relationships, and niche evolution of *Adiantum* remain poorly understood.

By applying advanced bioinformatics techniques and integrating information from molecular (chloroplast and nuclear data), morphological and environmental data, we aim to elucidate the phylogenetic relationships of *Adiantum* in Amazonia and to explore to what degree the diversification of *Adiantum* species is related to niche evolution, dispersal limitation and hybridization. The results will not only improve our understanding of the biodiversity of *Adiantum* itself but will also contribute to understanding the formation of biodiversity in the Amazon region in general.

### S.231.3 Understanding the evolutionary and biogeographical history of the enigmatic pantropical family Putranjivaceae

Irene Villa-Machío¹, Alejandro Quintanar², Alexander G. Linan¹, David Harris³, Patricia Barberá¹

1 Missouri Botanical Garden, St. Louis, USA. 2- Real Jardín Botánico - CSIC, Madrid, Spain. 3 Royal Botanic Garden Edinburgh, Edinburgh, UK.

Tropical ecosystems are recognized as one of the most biologically diverse regions on Earth. The "odd-man-out" pattern proposes that Tropical Africa is less diverse than both Neotropics and Tropical Asia. Although this is true for many vascular plant groups, this is not the case for the pantropical family Putranjivaceae. It is a complex and species-rich group that includes two genera: *Putranjiva* (4 spp., restricted to Asia) and *Drypetes* (219 spp.). Asia contains the greatest number of species belonging to *Drypetes* (113 spp.), followed by Africa (86 spp.) and significantly less in America (20 spp.). The high number of African species recently described indicates that the diversity of Putranjivaceae on this continent has been underestimated. The evolutionary and biogeographical history of the Putranjivaceae has never been studied due to the lack of both an updated taxonomic scheme (the only extant infrageneric classification of *Drypetes* was published in 1922 by Pax & Hoffmann) and a comprehensive phylogeny for the family. Herbaria store vast collections of plant specimens accumulated over several centuries, and recent advances in DNA extraction methods and sequencing techniques allow researchers to include degraded DNA in their studies. We aim to analyze ~200 herbarium specimens, accounting for over 90% of the Putranjivaceae family's diversity, to reconstruct their phylogenomic relationships. Target
<figure><img src="image_538.png" /></figure>

capture sequencing combined with genome-skim-
ming (HybSeq) is favored due to its compatibility with
old herbarium material and ability to produce numer-
ous low-copy nuclear orthologs and organellar DNA.
This study will advance understanding of the evolution-
ary history of Putranjivaceae and demonstrate how a
strong phylogenomic hypothesis can inspire and direct
future taxonomic research, support species identifica-
tion and elucidate important inquiries regarding their
evolution and biogeography.

S.231.4 Sapotaceae
across time and space: a
taxonomic and historical
biogeographic perspective

Raquel C. Pizzardo¹, Deise Pereira
Gonçalves¹, Andre Chanderbali², Douglas
Soltis², Pam Soltis², Stephen Smith¹,
Christopher Dick¹

1 University of Michigan, Ann Arbor, Michigan, United
States. 2 University of Florida, Gainesville, Florida, USA.

Sapotaceae is one of the most important plant families
in the world. With around 1,250 species and 62 genera,
Sapotaceae is a pantropical family, and is usually re-
stricted to lowland tropical rainforests. However, the tax-
onomy of the family is unstable and lacks in information
of this ecologically important groups of angiosperms in
the tropics. Many incongruences between phylogeny
and classification in Sapotaceae have been noted, as
well as alternative topologies for species-level phylog-
enies. Here, we generate a higher sampled Sapotaceae
phylogeny and, for the first time, we aimed to determine
the geographical origin of the pantropical family and
the roles vicariance and dispersal have played in shap-
ing its modern distribution. We used target sequence
capture data from the Angio353 probe for 199 taxa. The
concatenated maximum likelihood molecular phylog-
eny was constructed using IQ-TREE (v. 1.6) considering
GTR+G and partition models, and 1000 bootstrap rep-
licates. Dates of diversification events were estimated
using two fossils and the penalized likelihood approach
(treePL). The subsequent dated phylogenies were com-
pared and analysed for biogeographical patterns us-
ing BioGeoBEARS. The phylogeny moderately recovered
the three subfamilies of Sapotaceae, showing relatively
high support for Sapotoideae but not for Chrysophy-
loideae. The phylogeny shows inconsistencies with the
current morphological classification. Our results indi-
cate that the ancestral range of the family was in East

Asia ca. 84 - 80 Mya, with dispersal to South America and Africa. Chrysophylloideae had a early diversification in Africa ca. 71 - 57 Mya, with subsequent dispersal to the Neotropics (two events) and Australasia (singles event) during the Palocene and Eocene. Sapotoideae had an early diversification in Africa ca. 71 - 50 Mva, with migration to Australasia and North America during the Eocene. Those results are somehow congruent with previous studies. Long-distance dispersal has been an important mechanism for range expansion in Sapotaceae.

S.231.5 Berries on bellflowers:
diversification patterns in
one of the fastest Andean
plant radiations

Ajith Ashokan¹, Justin C. Bagley², Nathan Muchhala¹

1 Department of Biology, University of Missouri - St. Louis, USA. 2 Department of Biology and Environmental Sciences, Auburn University at Montgomery, Alabama, USA.

The centropogonids within Lobelioidae (Cam-
panulaceae), consist of *Burmeistera* H.Karst. & Tri-
ana, *Centropogon* C.Presl, and *Siphocampylus* Pohl,
stand out as one of the rapidest plant radiations in
the Neotropics. Remarkably, this alliance gave rise to
approximately 550 species in less than three million
years. Traditionally, fruit traits were employed to dis-
tinguish genera within centropogonids, where *Sipho-
campylus* is identified by capsules, and *Burmeistera*
and *Centropogon* by berries. Inflated berries are a
distinctive feature of *Burmeistera*, representing a
third of its species diversity. Our study compares in-
flated and fleshy berries in *Burmeistera*, examining
differences in elevation, as well as the evolution of
morphological, ecological, and geographical traits.
This analysis, conducted within a phylogenomic
framework, provides insights into how these factors
have influenced the diversification of *Burmeistera*.
Our findings indicate that inflated fruits evolved mul-
tiple times in the phylogeny of *Burmeistera* species,
with inflated and fleshy berries occupying distinct
adaptive regimes, particularly concerning elevation.
Moreover, the diversification patterns in *Burmeis-
tera* varied among species distributed in the Chocó
biogeographic region, exhibiting a comparatively
reduced frequency of inflated berries. We propose
that studies focused on the conservation of often
overlooked taxa, like *Burmeistera*, could significant-
<figure><img src="image_539.png" /></figure>

ly impact the preservation of severely threatened
cloud forest ecosystems.

S.232 GENOMICS

S.232.1 Ancient DNA recovered
from lake sediment with
Angiosperms353 shows
plant composition shifts with
paleoclimate

Madeline Slimp¹, Lisa Martinez², Glen Macdonald², Don Hankins³, Matthew Kirby⁴, Josh Kapp¹, Sebastian Melrose¹, Beth Shapiro¹, Rachel Meyer¹

1 Department of Ecology and Evolutionary Biology, University of California Santa Cruz, California, USA. 2 Department of Geography, University of California Los Angeles, California, USA. 3 Geography and Planning Department, California State University Chico, California, USA. 4 Department of Geological Sciences, California State University Fullerton, California, USA.

Humans have steadily been in Southern California for
14,000 years. Despite this legacy of human presence,
studies showing the historical composition of the or-
ganisms that cohabited this Southern California with
humans are scant. Sedimentary ancient eDNA can be
used as a tool to reconstruct thousands of years of
plant and mammal presence records and may pres-
ent a more sensitive spatiotemporal scale than pollen
records. We sequenced the mammal and plant DNA
present in a sediment core from Lake Elsinore, span-
ning 24,000 years of natural history and 10,000 years
of human settlement. Preservation of environmental
DNA is poor in warm climates, so we tested the An-
giosperms353 Target Capture Kit's effectiveness in in-
creasing the proportion of diagnostic plant sequences
for ancient metagenomic samples. We find that the
Angiosperms353 libraries have a greater proportion of
reads mapped on average, and a greater plant tar-
get richness. From the target capture data, we seek
to trace ethnobotanical families, like Rutaceae, Faga-
ceae, and Apiaceae, to characterize the landscape
around the time of human arrival to understand some
of the challenges and opportunities presented to early
inhabitants. Further, we associate characteristic en-
vironmental changes, like shrubland dominance and
absence of widespread taxonomic groups, with a
newly reconstructed charcoal history, suggesting that

humans have been ecosystem engineers via con-
trolled use of fire for thousands of years. This project
validates the preservation and recovery of ancient
eDNA using Angiosperms353 in warm-climate sedi-
ment cores from southern California, which can be a
tool that helps define the role of humans in shaping
California's ecological history.

S.232.2 An update on
plant genome size
diversity: contributing
towards a comprehensive
understanding across
angiosperms

Jaume Pellicer¹,², Maarten Christenhusz²,³,
J. Leitch², Oriane Hidalgo¹,²

1 Institut Botànic de Barcelona, CSIC-CMCNB, Barcelona, Spain. 2 Royal Botanic Gardens, Kew, Richmond, UK. 3 Department of Environment and Agriculture, Curtin University, Perth, Australia.

Research into genome size evolution in angiosperms
has increased significantly, uncovering a huge diver-
sity across different taxonomic lineages. Despite the
efforts made and the vast amount of data generated
(> 10,000 species), which have been carefully collated
onto the plant DNA C-values database (http://data.
kew.org/cvalues/), many taxonomic families are still
lacking a single estimate. Certainly, such taxonomic
gaps are particularly notable in angiosperms, where
nuclear DNA contents are only available for about 3,000
genera out of ca. 13,000 genera currently recognised,
and over 10,000 species (ca. 2.5% of the ca. 352,000
species recognised). At the family level, this translates
into estimates for 270 families out of 417 (sensu the An-
giosperm Phylogeny Group IV), i.e., nearly 65% of the
currently accepted diversity. With the already avail-
able data, we have been able to unveil a staggering
diversity of nuclear DNA contents in angiosperms that
spans up to 2400-fold. Notwithstanding, the question
still remains as what is the extant diversity of genome
sizes in angiosperms? And what is yet to be uncovered?
In order to bring further robustness to our current un-
<figure><img src="image_540.png" /></figure>

derstanding of angiosperm genome size diversity, we set up an initiative aimed at filling most -if not all- the taxonomic caveats, starting at the family level. The unceasing production of novel genome size data, complemented with an increasingly robust understanding of the worldwide distribution of organisms, has opened unprecedented prospects for investigating the role of genome size in shaping and influencing the survival of extant biodiversity. Our goal is to produce at least one estimate per each accepted family (122 families represented so far, i.e., 94%), focusing our efforts on those lineages largely understudied, and interpret these data within an evolutionary context, investigating the existing links between the patterns and processes shaping extant plant genome diversity.

### S.232.3 The *Sapria himalayana* genome provides new insights into the lifestyle of endoparasitic plants

Xuelian Guo¹, Xiaodi Hu², Jianwu Li³,
Bingyi Shao¹, Yajun Wang¹, Long Wang²,
Kui Li², Dongliang Lin¹, Hanchen Wang¹,
Zhiyuan Gao¹, Yuannian Jiao¹, Yingying
Wen¹, Hongyu Ji¹, Chongbo Ma¹, Song Ge¹,
Wenkai Jiang², Xiaohua Jin¹

1 State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China. 2 Novogene Bioinformatics Institute, Beijing, China. 3 Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun Township, Mengla County, Yunnan, China.

*Sapria himalayana* (Rafflesiaceae) is an endoparasitic plant characterized by a greatly reduced vegetative body and giant flowers; however, the mechanisms underlying its special lifestyle and greatly altered plant form remain unknown. To illustrate the evolution and adaptation of *S. himalayana*, we report its *de novo* assembled genome and key insights into the molecular basis of its floral development, flowering time, fatty acid biosynthesis, and defense responses. The genome of *S. himalayana* is ~1.92 Gb with 13,670 protein-coding genes, indicating remarkable gene loss (~54%), especially genes involved in photosynthesis, plant body, nutrients, and defense response. Genes specifying floral organ identity and controlling organ size were identified in *S. himalayana* and *Rafflesia cantleyi*, and showed analogous spatiotemporal expression

patterns in both plant species. Although the plastid genome had been lost, plastids likely biosynthesize essential fatty acids and amino acids (aromatic amino acids and lysine). A set of credible and functional horizontal gene transfer (HGT) events (involving genes and mRNAs) were identified in the nuclear and mitochondrial genomes of *S. himalayana*, most of which were under purifying selection. Convergent HGTs in *Cuscuta*, *Orobanchaceae*, and *S. himalayana* were mainly expressed at the parasite-host interface. Together, these results suggest that HGTs act as a bridge between the parasite and host, assisting the parasite in acquiring nutrients from the host. Our results provide new insights into the flower development process and endoparasitic lifestyle of Rafflesiaceae plants. The amount of gene loss in *S. himalayana* is consistent with the degree of reduction in its body plan. HGT events are common among endoparasites and play an important role in their lifestyle adaptation.

### S.232.4 Extreme chromosome copy number variation and unusual suite of transferred sequences characterize mitogenomes of *Gastrodia*

Hanchen Wang¹, Deyi Wang², Bingyi Shao¹, Xiaohua Jin¹

1 State Key Laboratory of Plant Diversity and Specialty Crops, Institute of Botany, Chinese Academy of Sciences, Beijing, China. 2 Naturalis Biodiversity Center, Leiden, the Netherlands.

The evolution of heterotrophy in plants has induced dramatic genomic alternations, such as for plastids, where extensive gene loss and size reduction are widely reported. Analogous to plastids are several extreme modifications discovered in mitochondrial genomes (mitogenomes) of parasitic plants. However, whether trophic reliance on symbiotic fungi (mycoheterotrophy) similarly results in mitogenomic alternations remains largely unknown. We present a comprehensive mitogenomic study for mycoheterotrophic plants based on 11 *de novo* assemblies of *Gastrodia* (Orchidaceae). These mitogenomes contain multiple chromosomes, range from 0.56 to 2.1 Mb in size, and exhibit several features are rarely, if ever, observed among other plants. Specifically, variations in chromosome copy number are universal, and in two assemblies, a chromosome exists at
approximately 15 times higher abundance than the conspecific average, resulting in the most extreme chromosomal copy number variation among any mitogenomes so far. Insertions from plastid and fungal genomes are unexpectedly scant, in contrast to those potentially rampant, species-specific, non-coding sequences transferred from the nucleus and distant plant taxa. Yet, despite the 3.8-fold size variation and highly variable intergenic sequence components, these mitogenomes harbor an ordinary complement of genes and introns, and exhibit moderate substitution rates of coding sequences, with no genes acquired via horizontal transfer. Taken together, our findings suggest a minor role of mycoheterotrophic lifestyle on mitochondrial coding sequences, but the extreme copy number variation across mitochondrial chromosomes and unusual combinations of transferred sequences set new benchmarks for architectural and content variation seen in plant mitogenomes, and hints at unexplored mechanisms governing mitogenomic evolution of these extraordinary heterotrophic plants.

### S.232.5 Reciprocal gene loss after whole-genome duplications contributes to species diversity in mangrove plants

Ranran Zhu¹, Suhua Shi¹*, Shaohua Xu¹**

1 Sun Yat-sen University, Guangzhou, China.
*lssssh@mail.sysu.edu.cn, **xushh27@mail.sysu.edu.cn

Whole-genome duplications (WGDs) are prevalent and provide extensive material in plant evolution process. The extensive gene loss and biased retention of duplicated genes after WGDs were proposed responsible for the environmental adaptation and species diversification, but the mechanisms are still rarely uncovered. In mangroves that inhabited intertidal environments independently from inland ancestors, we found the clades experienced WGD events had higher species diversity. We choose *Avicennia* genus, a typical mangrove clade with specified phenotypes and a high species diversity, to explore the possible molecular mechanisms of WGD in promoting species divergence. We first assembled seven high-quality mangrove genomes of the *Avicennia* genus using PacBio Single-Molecule Real-Time sequencing. Then, we identified two recent WGD events in *Avicennia*. The more recent one

is *Avicennia*-specific, coinciding with the genus' origin approximately 46 Mya. The WGD retained gene duplications are involved in high salt tolerance and nutrient absorption, contributing to the genus' adaptation to intertidal environments. We test the role of reciprocal gene loss (RGL) in the rapid species divergence of the *Avicennia* genus. Combined with gene collinearity and phylogenetic analyses, we accurately identified RGL events among these species. Interestingly, a few RGLs between sister species are closely related to reproduction process, such as pollen tube invasion of the stigma. Further functional studies suggested that RGLs may cause reproduction isolation between sister species. In summary, our study uncovered the role of WGD in environmental adaptation and provided evidence that RGL after WGDs may be a potential speciation mechanism in mangrove plants.

### S.232.6 Phylogenetic Analysis of Marchantia Species in Sri Lanka Based on rbcL, psbA, and ITS2 Sequences

Nanayakkarawasan Carijjawaththagei
Sumudu Ruklani¹, Sumudu C. K. Rubasinghe¹

1 Department of Botany, Faculty of Science, University of Peradeniya, Sri Lanka.

This study presents the first comprehensive phylogenetic analysis of *Marchantia* species in Sri Lanka using nucleotide sequences from three distinct genetic markers: *rbcL*, *psbA*, and *ITS2*. The aim of this research was to elucidate the evolutionary relationships among different *Marchantia* taxa within the Sri Lankan context, providing valuable insights into the genetic diversity and evolutionary history of these liverworts. A total of 20 *Marchantia* samples representing diverse geographical locations across Sri Lanka were collected and analyzed. DNA was extracted, and the targeted regions (*rbcL*, *psbA*, and *ITS2*) were amplified through polymerase chain reaction (PCR). Subsequent sequencing and alignment were performed to construct phylogenetic trees using MEGA version 11.0.13. The resulting trees were then subjected to bootstrap analysis to assess the robustness of the inferred relationships. Our phylogenetic analysis revealed distinct clustering patterns within the *Marchantia* species sampled from
<figure><img src="image_541.png" /></figure>

Sri Lanka. The utilization of multiple markers (*rbcl*, *psbA*, and ITS2) provided a more comprehensive understanding of the evolutionary dynamics, offering insights into both conserved and variable regions of the genome. Furthermore, the study identified potential cryptic species and clarified the taxonomic relationships among *Marchantia* populations in Sri Lanka. The implications of these findings extend beyond the realm of taxonomy, contributing to our understanding of the biogeography and evolutionary

processes shaping the diversity of *Marchantia* in this region. This research not only adds to the growing body of knowledge concerning liverwort evolution but also underscores the importance of incorporating multiple genetic markers for a robust phylogenetic inference. The insights gained from this study have implications for conservation efforts and provide a foundation for future investigations into the ecological and physiological adaptations of *Marchantia* species in Sri Lanka.

# S.233 FROM MULBERRIES TO FIGS: STUDIES IN THE EVOLUTION OF MORACEAE

## S.233.1 Revisiting C.C. Berg's and E.J.H. Corner's treatments of Moraceae: morphology and its role in the evolution of the fig family

Nicole Mitidieri-Rivera<fnref n="1" />, Elliot Gardner²,

Leandro Pederneiras<fnref n="3" />, Alexander

Damián-Parizaca<fnref n="1" />, Kenneth J. Sytsma<fnref n="1" />

The diversification of angiosperms poses an intriguing evolutionary puzzle that has been attributed to the origin of the flower. Pollinator-mediated selection stands as a key force driving the astonishing diversity of floral forms observed in angiosperms, but its role in the diversification of Urticalean rosids has been neglected. Utilizing the Moraceae family as a model system, we aim to investigate how changes in floral traits have influenced its floral disparity and the emergence of unique clades, such as the figs. This pantropical, monophyletic family boasts a remarkable floral diversity across its 46 genera and ca. 1,200 species. Despite the family's extensive morphological diversity, limited studies have explored the role of floral traits in its evolution and diversification. Previous classification schemes by C.C. Berg and E.J.H. Corner, primarily based on morphology,

led to conflicting taxonomic circumscriptions due to the family's homoplasious nature. Recent advances in molecular techniques and phylogenomic analyses have unveiled deep-seated relationships among Moraceae tribes, shedding light on the evolution of floral structures and reproductive mechanisms. The time is now ripe to revisit Berg's and Corner's treatments of Moraceae. Leveraging the latest phylogenomic study in the fig family, we applied model-based phylogenetic comparative methods to translate hypotheses of morphological evolution under pollinator-mediated selection. We inferred ancestral character states and conducted trait-dependent diversification analyses based on a literature review and a comprehensive Moraceae dataset of 529 species. Understanding the intricate web of factors influencing the diversification of Moraceae remains a dynamic area of research, offering crucial insights into the macroevolutionary trajectories of one of the most diverse groups of angiosperms.

## S.233.2 An updated classification of Moraceae supported by stable phylogenomic hypotheses

Elliot M. Gardner<fnref n="1" />

The Moraceae is an ecologically and economically important family with a worldwide distribution centered in the tropics. Notable species include species of *Ficus* (figs), *Artocarpus* (breadfruit and

<footnote n="1">1 Department of Botany, University of Wisconsin-Madison, Wisconsin, USA. 2 Department of Biology, Case Western Reserve University, Ohio, USA.</footnote>

<footnote n="3">3 Diretoria de Pesquisa, Instituto de Pesquisa do Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil.</footnote>

<footnote n="1">1 Department of Biology, Case Western Reserve University, Cleveland, Ohio, USA.</footnote>
<figure><img src="image_542.png" /></figure>

jackfruit), *Morus* (mulberries), and others. Classification within the family based on morphology has led to instability over the past century due in part to the difficulty in distinguishing preserved ancestral or convergent characters from truly plesiomorphic characters. Historical classification systems have particularly disagreed on the importance of stamen position, which may be straight or inflexed in bud, the latter a notable adaptation to wind pollination. Inflorescence architecture varies widely from spicate inflorescences in the Moreae to the closed syconium of *Ficus* or the flattened disc of *Dorstenia*, yet differences in the individual flowers may be more cryptic. Two decades of molecular phylogenetic analyses, the most recent incorporating hundreds of genes as well as analyses of introduction, have clarified evolutinoary relationships and transitions within this family. After reviewing the current state of phylogenetic reconstructions and the morphological traits that characterize the major clades, this paper will propose a comprehensive updated classification of Moraceae that is consistent phylogenetic reconstructions but morphologically tractable. The author hopes that this updated classification will provide stability for further work on Moraceae and bring formal taxonomic names in line with phylogenetic evidence.

**S.233.3 Syncarpous fruits from the Early Oligocene Capella Flora in Queensland, Australia suggest affinities to the Moraceae**

Andrew C Rozefelds¹

1 Queensland Museum, Collection and Research Centre, Hendra, Queensland, Australia.

Fruits composed of a many individual fruitlets that are united into a complex structure are described as a syncarpium or a sorosus. Syncarpia occur in diverse and phylogenetically unrelated families, such as in the monocots Araceae, Bromeliaceae, Cyclanthaceae, Pandanaceae, and dicots Balanophoraceae, Bataceae, Chloranthaceae, Cornaceae, Moraceae, Rafflesiaceae, Rubiaceae and Urticaceae. Permineralised fruits from the Oligocene Capella locality in Queensland consists of many fruitlets, and the seeds occur in the upper portion of each fruitlet. The fruitlets form connate radiating segments, which are interpreted as being de-

rived from the perianth. These radiating segments extend from the centre to the margin of the fruit and adjacent perianth apices appear to be fused apically, forming an irregular pentagonal-hexagonal imbricate surface which shows no consistent phyllotactic pattern. It was possible to exclude the monocot families and Balanophoraceae because the arrangement of seeds in the fruits of these families typically exhibit a regular phyllotaxy, which is less evident in the Pandanaceae. The structure of the fruit and seed shape in the fossil differs from that in Rafflesiaceae. The fossil also has a complex internal structure consisting of thin connate radiating elements that are closely aligned and in this respect the fossils differ from the internal fruit morphology of Cornaceae, Chloranthaceae, Rubiaceae, Bataceae and Urticaceae. Comparison of character traits across these families suggests that these fossil syncarpous fruits are considered to have affinities with the Moraceae. While most fruits in Moraceae are syncarpous the fruit morphology of genera in the family is highly diverse, although five-sided fruits are not currently known. The con-nately arranged fruitlets and pentagonal-hexagonal external appearance suggests that the closest affinities of these fossils lie with the Artocarpeae.

**S.233.4 Exploring evolution of breeding systems in Moraceae within the context of correlated character traits**

Julianne Phipps¹,², Elliot Gardner³,⁴, Nyree Zerega¹,²

1 Northwestern University, Evanston, USA. 2 Chicago Botanic Garden, Glencoe, USA. 3 Florida International University, Miami, USA. 4 Case Western Reserve University, Cleveland, USA.

Monoecy, the presence of discretely sexed flowers on the same individual, and dioecy, the presence of only unisexual individuals, are both relatively rare breeding systems among angiosperms (Renner 2014) but yet are the only breeding systems, with few exceptions, found among the roughly 1200 extant members of the Moraceae family. Dioecy, in particular, has long been considered as an evolutionary endpoint due in large part to the perceived reproductive hurdles such a breeding system presents in plants. But there is an increasing body of evidence that dioecy can and will revert to other breeding
<figure><img src="image_543.png" /></figure>

IBC
2024

XX International
Botanical
Congress
Madrid Spain

systems, demonstrating lineage extinction is not a foregone conclusion. With this increasingly accepted, exploration into the surrounding factors is merited. Using an updated molecular phylogeny, the evolutionary patterns of these breeding systems within Moraceae are contextualized through their relationships with character traits chosen either for their long association with dioecy or for their potential to contribute to resilience in the face of habitat disruption or periods of low reproductive success. Evaluating these factors in tandem will reveal key evolutionary milestones and adaptive connections which enabled Moraceae to diversify into the ecologically important family it is today.

References: Renner, S. S. 2014. The relative and absolute frequencies of angiosperm sexual systems: Dioecy, monoecy, gynodioecy, and an updated online database. American Journal of Botany 101:1588–1596.
**S.234 THE EVOLUTION AND BIOGEOGRAPHY OF APOMICTIC PLANTS. SESSION 1**

**S.234.2¡1 Female-male crosstalk affects male meiosis and pollen development in sexual and apomictic Limonium species**

Ana Delaunay Caperta¹

¹ Linking Landscape, Environment, Agriculture and Food Research Center, Associate Laboratory TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, Lisboa, Portugal.

Breeding systems were extensively studied by Baker, who has been influential in the development of evolutionary and biogeographical hypotheses for Plumbaginaceae, as in Limonium (sea-lavenders). This genus is a remarkable case-study as apomicts have a large general distributional success, although most of the relevant questions were not yet answered which hampers an understanding about apomixis origins. Limonium species present a polymorphic sexual system associated to flower polymorphisms such as ancillary pollen and stigma and/or heterostyly, under sporophytic control that prevents self and intramorph mating. Most sexual and apomict species are self-incompatible, the first usually form meiotically reduced embryo sacs and viable pollen. While apomicts can originate unreduced embryo sacs and pollen ranging from low to high fertility or it is not produced at all. To explore the mechanisms beyond these reproduction modes, ovule transcriptome profiling of sexual and apomict species was carried out. Our investigations revealed several novel challenges, among which female-male interactions associated with reproduction modes.

**S.234.2 Apomixis and polyembryony in plants of Cerrado, the Neotropical savannas in Central Brazil**

Clesnan Mendes-Rodrigues¹, Rafaela Cabral Marinho¹, Diana Salles Sampaio¹, Gastón O. Carvallo², Luciana Nascimento Custódio¹, Ana Paula de Souza Caetano³, Renata Carmo-Oliveira¹, Paulo Eugênio Oliveira¹

¹ Universidade Federal de Uberlândia, Uberlândia, MG, Brazil. ² Pontifícia Universidade Católica de Valparaíso, Valparaíso, Chile. ³ Universidade Federal de Mato Grosso, Cuiabá, Brazil.

Polyembryony involves multiple, either sexual or asexual embryos in the same seed. Asexual embryos are commonly the result of apomixis processes. Although sexual systems and monoembryony predominate among Cerrado plants, the Neotropical savannas in Central Brazil, recent studies have shown increasing numbers of apomictic species, many of them polyembryonic. Here we surveyed the polyembryony among Cerrado plants and connected its occurrence with apomixis. We compiled records of embryonic patterns - monoembryony or polyembryony (216 species) and breeding systems (139 species) from literature, and also gathered original data (91 species). We observed the rate of polyembryony either by dissecting seeds or evaluating the emerging seedlings per seed after germination experiments. Plant species were classified as exhibiting monoembryony, low polyembryony (<5%) or higher polyembryony rate (>5%). Polyembryony was observed in 72 species (31.8%). Surveyed species were either self-incompatible (66 species; 47.5%), self-compatible (33 species; 23.7%), apomictic (28 species; 20.1%) or dioecious (12 species; 8.6%). Among apomictic species, 89.3% (N = 25) were polyembryonic. Percentage of polyembryonic seeds ranged from 0.09% to 98.4%, with sporophytic apomicts exhibiting usually higher rates of polyembryony. Polyembryony and
<figure><img src="image_544.png" /></figure>

apomixis in Cerrado plants seem to be linked to dioecy and polyploidy, and widely distributed woody species. Although apomixis and polyembryony are common in taxa such as Bignoniaceae, Fabaceae, Malvaceae and Melastomataceae, we did not find any clear phylogenetic signal for the distribution of these traits. Polyembryony rate higher than 5% proved to be a good indicator of apomixis. However, polyembryony was absent in some apomictic specie and, in several cases, was even linked to sexual reproduction. Polyembryony associated with apomixis seems to be a common reproductive alternative in savanna plants rather than a reproductive abnormality. Moreover, these traits will be important for plant conservation strategies in this threatened biome. Acknowledgments: We acknowledge CAPES, FAPEMIG and CNPq funding.

### S.234.3 Multiple origin of widespread apomictic Hieracium halleri: phylogenomic and cytogenetic evidence

Begoña Quirós-de-la-Peña¹,², Ladislava Paštová², Jindřich Chrtek², Eliška Záveská¹,², Yann J. K. Bertrand², Jiřina Josefiová², Shook Ling Low², Simon V. Corrales², Barbora Tomešová², Zuzana Sejfová², Pavel Zdvořák¹, Alexander Belyayev², Patrik Mráz¹

¹Charles University, Prague, Czech Republic. ²Institute of Botany of the Czech Academy of Sciences, Průhonice, Czech Republic.

Hieracium s.str. (Asteraceae) is a highly diverse genus that occurs in a wide range of environments, from lowlands to the alpine zone. It is known for its notorious taxonomic complexity, caused by widespread past interspecific hybridisation. This process has been closely linked to polyploidisation and apomixis, which has ensured the persistence of otherwise sterile hybrids. As a result, *Hieracium* is the largest apomictic-sexual genus among angiosperms, whose diversity is dominated by apomictic polyploid species. However, very little is known about the evolutionary and biogeographical history of these apomictic polyploids. We aim to decipher the evolutionary history of the alpine apomictic species *H. halleri*, which probably arose from hybridisation between *H. alpinum* and *H. intybaceum*. We also ask if

*H. halleri* originated only once or if it is of recurrent hybrid origin. To achieve these aims, we combined cytogenetic (FISH and GISH), flow cytometric (assessment of mode of reproduction), and molecular (RADSeq, cpDNA) approaches. This multidisciplinary approach is applied to plants collected across the range of the species, which shows a large disjunction between the Alps and the Western Carpathians. We found that despite strictly apomictic mode of reproduction, *H. halleri* is cytogenetically variable taxon, both in chromosome number (prevailing are triploids, tetraploids are very rare) and karyotype pattern (variation in number and positions of 5S rDNA, 45S rDNA and HintCL-82 repetitive DNA clusters, and unbalanced translocations). Prevailing triploid *H. halleri* cytotype contains two genomes of *H. alpinum* and one genome of *H. intybaceum*, the pattern explaining the much closer morphological affinity of *H. halleri* to *H. alpinum*. Furthermore, cytogenetic and phylogenomic data indicate multiple origin of *H. halleri*. To conclude, multiple hybridisation events, post-hybridisation chromosomal rearrangements, and migration to the Western Carpathians have shaped molecular and biogeographic histories of this species.

### S.234.4 Evolution and biogeography of the Ranunculus auricomus complex in marginal areas: from the Mediterranean to the circumarctic

John Paul Bradican¹,², Salvatore Tomasello¹, Judith Vollmer³, Evelin Krol⁴, Elvira Hörandl¹

1 Albrecht-von-Haller Institute for Plant Sciences, Göttingen, Germany. 2 Georg-August University School of Sciences (GAUSS), Göttingen, Germany. 3 Linköping University, Linköping, Sweden. 4 Georg-August University of Göttingen, Göttingen, Germany.

Young species complexes represent prime subjects for the study of speciation, hybridization and range expansion. The apomictic mode of propagation sometimes expressed in such groups can exacerbate the morphological and taxonomic complexity characteristic of hybridizing species complexes, as well as facilitating rapid expansion into new habitats. We focus on the facultatively apomictic *Ranunculus auricomus* complex in order to investigate the evolution, bio-
<figure><img src="image_545.png" /></figure>

geography and taxonomic status of geographical-
ly marginal populations of this young (<1 mya) and
rapidly radiating group. At the southern and north-
ern edge of the groups range apomixis is the primary
mode of propagation, with sexual reproduction occur-
ring only rarely. Taxonomically, *Ranunculus auricomus*
agg. is composed of a handful of sexually reproducing
basal lineages occuring in temperate Europe, which
through repeated hybridization have begotten man-
ifold polyploid apomictic lineages. Given this, we also
examine the patterns of ancestry in marginal areas,
utilizing phylogenomic methods including subge-
nomic phasing. At the southern periphery we find no
additional sexually reproducing species, supporting
the recognition of many newly described apomictic
hybrid taxa in the region as nothotaxa. In the circum-
boreal-circumarctic zones we focus on a particular
morphogroup, typified by the diminutive *Ranunculus
monophyllus* Ovcz. Individuals included in this mor-
phogroup exhibit dwarf growth, high ploidy levels (4x-
6x) and obligate apomixis. In order to test the plasticity
of traits distinguishing *R. monophyllus* from other mor-
phogroups, we conducted climate chamber experi-
ments which showed little phenotypic plasticity in key
morphological traits in response to temperature. We
conclude that dwarf growth is adaptive and evolved
multiple times during colonization of Northern mar-
ginal areas. Biogeographical analyses of the whole
complex based on phylogenomic data will show the
expansion of the *R. auricomus* complex in space and
time, contributing to our understanding of geographi-
cal parthenogenesis.

S.234.5 Evaluating a
drought-driven hypothesis
for the origin of obligate
apomixis in ferns

Amanda L. Grusz¹,², Michael D. Windham³

1 Department of Biology, University of Minnesota Duluth, Duluth, USA. 2 Department of Botany, Smithsonian Institution, Washington, USA. 3 Department of Biology, Duke University, Durham, USA

Obligate apomixis -- asexual reproduction by seed,
spore, or egg -- has evolved repeatedly across the
tree of life, in diverse organisms ranging from animals
(such as reptiles, insects, and fishes) to angiosperms
and other plants. Despite its many origins, and the in-
triguing ecological and evolutionary parallels among
them, little is known regarding the causes and long-
term consequences of this heritable reproductive

syndrome. Some studies suggest that drought, or
periodic water limitation, could be key to driving the
repeated evolution of obligate apomixis. To evaluate
the drought hypothesis, we are uniting genomic, spa-
tial, environmental, and life history data (across mul-
tiple evolutionary and ecological scales), leveraging
ferns as a model system. Current estimates indicate
that 10-30% of ferns exhibit obligate apomixis, which
has evolved repeatedly in xeric and monsoonal en-
vironments around the world. Dry environments im-
pose major constraints on plant life histories and the
fern life cycle is especially vulnerable. In this study, we
focus on North American desert ferns, integrating re-
productive traits (karyotype, gametophyte develop-
ment, and spore size/number), climate and micro-
habitat, and phylogenomic data to specifically ask:
Does environmental niche predict obligate apomixis
or its constituent traits in desert ferns of North Amer-
ica? This work aims to further bridge generational
gaps in technical expertise among next-generation
researchers for a variety of cutting-edge and clas-
sical approaches, stimulating interdisciplinary stu-
dent-driven research that emphasizes the value and
relevance of museum specimens for addressing fun-
damental biological questions.

S.234.6 The origin and evolution of apomixis-related chromosomes in Boechera (Brassicaceae)

Terezie Mandáková¹, Michael D. Windham², Martin A. Lysak¹

1 Central European Institute of Technology, Masaryk University, Brno, Czech Republic. 2 Department of Biology, Duke University, Durham, NC, USA.

The genus *Boechera* (Brassicaceae) comprises ap-
proximately 480 genetically distinct taxa, predom-
inantly distributed in North America. Characterized
by a basic chromosome number of x = 7, the genus
includes diploid sexuals (2n = 14), diploid apomicts
(2n = 14, 15), and triploid apomicts (2n = 21, 22). The
extensive morphological diversity within the genus
arises from frequent hybridization among diploid
species, leading to the emergence of apomictic
diploid hybrids. Triploids have independently arisen
through hybridization between sexual and apomic-
tic diploids. Notably, apomictic *Boechera* plants
feature two heterochromatic B-like chromosomes
(Het and Del). With a small genome size, close evo-
lutionary ties to Arabidopsis, and the coexistence of
<figure><img src="image_546.png" /></figure>

diploid sexual and apomictic lines, *Boechera* stands as a unique model system for exploring genomic changes associated with apomixis. This study, employing cutting-edge cytogenomics and phylogenomics approaches, delves into the genome structure and evolutionary dynamics of sexual and apomictic *Boechera* plants. By unveiling the origins

of chromosomes linked with apomixis, our findings contribute valuable insights into the broader cytogenetic foundations of apomixis, advancing our understanding of reproductive strategies in plants.

Acknowledgments: This work was supported by the Czech Science Foundation (grant number 24-11371S).

# S.235 INTEGRATING ECOLOGY INTO MACRO AND MICROEVOLUTIONARY STUDIES PROBLEMS AND OPPORTUNITIES IN CURRENT AND PAST DATA SOURCES

## S.235.1 Ecological and evolutionary drivers of current plant diversity in North America

Pamela S. Soltis¹

1 Florida Museum of Natural History, University of Florida, Gainesville, USA.

The North American continent is characterized by striking diversity in climate, geology, and soil, which have together shaped patterns of plant diversity. With nearly 40,000 species of seed plants and >20% of the world's seed plant flora, North American plant communities differ in species richness, phylogenetic diversity, and their resilience in the face of climate change. Analyses of eco-evolutionary dynamics have demonstrated processes of community assembly and species diversification that have contributed to geographic structure of plant diversity at continental, regional, and local levels. For example, differential patterns of species diversification and temporal impacts of community assembly appear to have led to distinct patterns of phylogenetic diversity in eastern versus western North America. Moreover, biodiversity hotspots were identified in Mesoamerica, central Mexico, California, and Florida, with corresponding centers of endemism in Mexico, the southwestern USA, and the southeastern USA. Ongoing studies are integrating traits, phylogenies, and distributional data to forecast risks and resilience – both phylogenetically and regionally – in the North American flora. The North American Coastal Plain, a global biodiversity hotspot that encompasses the southeastern USA and extends from Texas to the northeastern USA,

is a composite of areas of paleo- and neoendemism, which in some cases correspond to regions of significant habitat heterogeneity. Environmental gradients in temperature and precipitation have shaped plant distributions across the hotspot, producing a patchwork of lineage-based adaptive zones. Many rare lineages converge in Florida, where areas of high and low phylogenetic diversity are in close juxtaposition and regions of high endemicity correspond to key structural features such as ridges and river valleys. These nested analyses at multiple geographic scales promise new perspectives for conservation.

## S.235.2 The splendid isolation of the South American continent for angiosperms: tempo, rates and the role of distance and temperature

E.K. López-Estrada¹, I. Sanmartín¹, A. Meseguer

1 Real Jardín Botánico, CSIC, Madrid, Spain.

South America was an island continent separated from other landmasses by large open seas for more than 50 million years. It was only when the Isthmus of Panama emerged from the sea, about 3 Mya, that South America came into contact with North America and the Great American Biotic fauna Interchange (GABI) began. The long-term confinement of South American mammals resulted in the evolution of an ex-
<figure><img src="image_547.png" /></figure>

ceptional endemic fauna, giving rise to the so-called "Splendid Isolation" diversification pattern proposed by Simpson. Nonetheless, whether this model can be extended to explain the outrageous diversification of the Neotropical angiosperm flora remains uncertain. It is unclear whether the isolation of South America was as strict for plants as it was for other groups of organisms, or whether angiosperms were able to disperse from other landmasses uninterruptedly during the isolation. It remains to be clarified as well, to what extent the arrival of new colonizers contributed to the extraordinary diversification pattern observed in the Neotropics today. To understand the effect that the disconnection of South America had on the evolution of the Neotropical flora, in this study we reconstruct the global biogeographic history of angiosperms and examine the proportion of dispersal events into and out of the Neotropics that occurred throughout the Cenozoic. We also investigate whether abiotic factors such as geographic distance or temperature directly affected dispersal opportunities into the Neotropics. Given the higher dispersal capacity of plants than animals, we hypothesize that the "Splendid Isolation" model will not hold for the Neotropical flora, and that several dispersal events between the Neotropics and other continents will be recovered during the Cenozoic.

**S.235.3 Reconstructing past niches: the link between quantitative paleobotany and phylogenetic reconstructions**

Candela Blanco-Moreno¹,², Virginia Valcárcel¹,³, Nagore G. Medina¹,³

1 Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain. 2 Biological Sciences Department, California State Polytechnic University, Humboldt, Arcata, CA USA. 3 Centro de Investigación en Biodiversidad y Cambio Global (UAM), Universidad Autónoma de Madrid, Madrid, Spain.

A comprehensive understanding of the ecological niches occupied by the ancestors of today's plant clades is essential for elucidating the evolutionary pathways that have shaped contemporary diversity. Integrating present-day observations with fossil records is crucial for studying these niches accurately. However, incorporating fossil information into phylogenetic ancestral reconstructions is challenging due to the limited direct information on the ecological niches of fossilized plants. Our work reviews the prima-

ry uses of fossils in niche reconstructions and identifies significant gaps in fossil knowledge. Deep time reconstructions often rely on morphological analyses of fossils due to difficulties in obtaining niche information from ancient specimens. Traits of extant plants like stomata, growth rings, tracheid size and thickening types, or foliar architecture (e.g. CLAMP) have proven to be indicative of present climatic conditions and in some cases are utilized for paleoclimatic reconstructions. However, the use of plant traits is based on inferences made on certain groups of extant plants and loses its applicability in deeper time as the taxonomic and atmospheric differences become so great that the comparison is unreliable (e.g. studies stomatal density in Carboniferous Pteridosperm leaves do not show consistent results). Additionally, the use of traits of the plant taxa themselves could lead to circular reasoning. Alternative methods, such as isotopic analyses and sedimentology, offer additional evidence on the abiotic conditions in which the plant fossilized evidence but face limitations in data scarcity. Our review examines plant traits, sedimentology, and stable isotope data from 15 fossil taxa (spanning from 470 to 100 Ma) that are commonly used to calibrate the land plant tree. This forms the basis for developing a methodological framework to infer the ancestral niches of the main clades of extant land plants, ensuring consistency and comparability in future research.

**S.235.4 Plant palaeoecology of the Late Cretaceous in Central Europe and its bearing on angiosperm dispersal**

Jiří Kvaček¹, Jana Čepičková¹,², Veronika Veselá², Petra Zahájská²,³ Mário M. Mendes⁴, Marcela Svobodová⁵

1 National Museum Prague, Czechia. 2 Charles University in Prague, Czechia. 3 University of Bern, Switzerland. 4 University of Coimbra, Portugal. 5 Institute of Geology, Prague, Czechia.

Early angiosperms and their environment are frequently discussed topics in palaeobotany. However, detailed reconstructions of their environment are not always available. In the present study we reconstruct five major terrestrial palaeoenvironments, some dominated by angiosperms, from the Cenomanian Peruc-Korycany Formation of the Bohemian Cretaceous Basin in Central Europe. The present taphonomic studies are based
<figure><img src="image_548.png" /></figure>

on long term observations of plant macro-, meso- and microfossils providing detailed information about plant communities during that time period. The environmental conditions and plant communities, ordered from sea inwards, are reconstructed as follows: 1) Salt marsh environments dominated by cheirolepidaceous confer *Frenelopsis alata*, 2) Coastal wetlands dominated by cupressoid conifers (typically *Cunninghamites lignitum*), 3) Meandering rivers characterised by lauroids (*Myrtophyllum geinitzii*), 4) Braided rivers dominated by lauroid angiosperm *Mauldinia bohemica* (with *Euca*-lyptolaurus sp. foliage), 5) Upland vegetation characterised by fern prairies. This study shows a diversity of angiosperms in alluvial plains, with prevailing lauroids and platanoids. The reconstruction of the upland vegetation, interpreted as fern prairie shows also a diversity of ancient angiosperm groups with particularly affinities to ANA group and Chloranthaceae. Comparisons of the Late Cretaceous (Cenomanian) palaeoenvironments with the Early Cretaceous (Barremian-Albian) palaeoenvironmental conditions from the Lusitanian Basin in western Portugal shows remarkable and interesting differences. In the Early Cretaceous environments, angiosperms are interpreted as herbaceous and shrubby plants growing in disturbed habitats. While in the Late Cretaceous angiosperms were already part of canopy forming arborescent and shrubby vegetation in alluvial plains of both meandering and braided rivers.

## S.235.5 A pipeline to include the species climatic heterogeneity and the complexity of the world's climate in ancestral reconstructions

V. Valcárcel¹,², M. Coca de la Iglesia¹, A. Gallego¹, J. Wen³, N.G. Medina¹,²

1 Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain. 2 Centro de Investigación en Biodiversidad y Cambio Global (UAM), Universidad Autónoma de Madrid, Madrid, Spain. 3 Department of Botany/MRC 166, Smithsonian Institution, Washington, DC, USA.

Current approaches that integrate climatic niche in evolutionary studies often fail to consider the climatic heterogeneity of species, the climatic context in which they live and the complexity of the World's climate. Indeed, evolutionary studies often resort to climatic classifications to deal with the World's climatic complexity

or to summary statistics to address the heterogeneity of the species climatic preferences. In this study we evaluate the impact of using different types of climatic data (discrete and continuous) and comparative approaches (character state, quantitative and probabilistic) to reconstruct climatic niche evolution in the Asian Palmates of Araliaceae, an example of the tropical-temperate diversity pattern. We used phylogenomic reconstructions, worldwide point-occurrence database of the Asian Palmates and five classification schemes of the World's climate. We used discrete categorization of genera (tropical or temperate) for the character state reconstruction and the first axis of a climatic PCA for the continuous-based reconstructions, using summary statistics for the quantitative approach and the complete climatic space of each genus for the probabilistic one. The character state and the quantitative reconstructions using maximum and minimum values were inconclusive. Instead, we disclosed a general preference of the Asian Palmates ancestors for the subtropical and tropical climatic transition when using the mean and median values. The probabilistic approach allowed us to uncover the narrow ancestral climate niches of the ancestors in comparison to the broad niches of the extant genera. We propose the probabilistic approach at least for lineages with high climatic heterogeneity or living in highly heterogeneous regions. However, since the precision of this probabilistic approach is highly dependent on the accuracy of the distribution data, we also provide a pipeline to consider climatic heterogeneity and the complexity of the World's climate for ancestral reconstructions in lineages in which the knowledge of species distribution is poor or biased.

## S.235.6 Phylogenetic diversity and regionalization of root nodule symbiosis

R.A. Folk¹, M.W. Belitz²,³, C.M. Siniscalchi¹, H.R. Kates², D.E. Soltis²,³,⁴,⁵, P.S. Soltis²,⁴,⁵, R.P. Guralnick²,⁵, L.M. Borges⁶

1 Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA. 2 Florida Museum, University of Florida, Gainesville, FL, USA. 3 Department of Biology, University of Florida, Gainesville, FL, USA. 4 Genetics Institute, University of Florida, Gainesville, FL, USA. 5 Biodiversity Institute, University of Florida, Gainesville, FL, USA. 6 Universidade Federal de São Carlos, São Carlos, SP, Brazil.

Among the most vexing questions in legume bio-geography is why non-nodulating and facultative-
ly nodulating legumes, i.e., those that do not or need not engage in RNS with rhizobia, are preponderant in the tropics, whereas extratropical areas have almost entirely nodulating legumes. Understanding the environments associated with loss of symbiosis would yield more precise insight into the ecological function that nodulation confers in natural ecosystems. Here we determine centers of species richness (SR), relative phylogenetic diversity (RPD) and centers of paleo- and neo-endemism, and regionalizations of phylogenetic diversity in the mimosoid clade of the legumes to understand the distribution and environmental associates of mimosoids lacking RNS (root nodule symbiosis). We built a phylogenetic tree of 1313 species and high-quality species distribution models for 1128 species representing the phylogenetic breadth of the mimosoid clade to identify the geographic distribution of RNS. Centers of significant RPD and endemism were

identified using a randomization approach, the latter using CANAPE. Phylogenetic regionalization used a distance-based phylogenetic beta-diversity approach. We recognized nine areas of contiguous high SR as distinct SR hotspots. Non-RNS species occur mainly outside hotspots but are closely correlated with high RPD. Absence of RNS was best predicted by high precipitation, and represents multiple independent phylogenetic assemblages in different biogeographic areas. SR hotspots are partly incongruent with centers of RPD and phylogenetic endemism. Lineages lacking RNS, likely to represent loss of symbiosis, are distributed in SR hotspots in Africa and the Americas, belong to biogeographically separate species assemblages, and are, in most cases, associated with relatively moist tropical environments with low temperature seasonality and high available soil nitrogen.

# S.236 EVOLUTIONARY TRENDS IN SKY-ISLANDS: NEW INSIGHTS IN THE SEARCH OF MAJOR BIOGEOGRAPHIC AND PHYLOGEOGRAPHIC PATTERNS

## S.236.1 Niche conservatism prevails in repeated long-distance colonization of Madagascar mountains by the genus Helichrysum (Compositae)

Carme Blanco-Gavaldà<fnref n="1" />, Cristina Roquet<fnref n="1" />, Genís Puig-Surroca<fnref n="1" />, Santiago Andrés-Sánchez², Sylvain Razafimandimbison³, Rokiman Letsara⁴, Nicola Bergh⁵, Glynis V. Cron⁶, Lucía D. Moreyra⁷, Juan Antonio Calleja⁸, Òscar Castillo<fnref n="1" />, Randall J. Bayer⁹, Frederik Leliaert¹⁰, Alfonso Susanna⁷, Mercè Galbany-Casals<fnref n="1" />

5 South African National Biodiversity Institute, Claremont, South Africa. 6 University of Witwatersrand, Johannesburg, South Africa. 7 Botanical Institute of Barcelona, Barcelona, Spain. 8 Autonomous University of Madrid, Madrid, Spain. 9 University of Memphis, Memphis, USA. 10 Meise Botanic Garden, Meise, Belgium.

Madagascar is a world's biodiversity hotspot, showing exceptionally high levels of species richness and endemism. Despite the island's prolonged geographic isolation (150 to 160 Ma from Africa, 84 to 90 Mya from India), most of its extant endemic plant species are the result of recent long-distance dispersals, mainly from continental Africa. The genus *Helichrysum* is a relevant study-case to explore the evolutionary and biogeographic history of Malagasy flora because it represents one-fifth of the Compositae species of the island. We generated a time-calibrated phylogeny of 350 *Helichrysum* species (including 60% of the Malagasy endemics) based on target-enrichment DNA sequence data and conducted ancestral range estimation analyses. Our results reveal at least six independent dispersal events to Madagascar from African regions since

<footnote n="1">1 Systematics and Evolution of Vascular Plants (UAB) - Associated Unit to CSIC by IBB, Bellaterra, Spain. 2 University of Salamanca, Salamanca, Spain. 3 Swedish Museum of Natural History, Stockholm, Sweden. 4 Herbarium of the Parc Botanique et Zoologique of Tsimbazaza, Antananarivo, Madagascar.</footnote>
<figure><img src="image_549.png" /></figure>

the Pliocene. Notably, Madagascar was colonized at least twice by lineages originating from the Tropical Afromontane region, leading to significant subsequent radiations in the island's highlands and mountains. The southern African montane grasslands have also played a key role in Madagascar's colonization, originating at least three clades on the island, one of which notably diversified. *Helichrysum mahafaly*, endemic to the arid SW region of Madagascar, was inferred to originate from an ancestor coming from the arid region of SW Africa. The similarity of habitats between source and colonized areas suggests the prevalence of niche conservatism, a common phenomenon in allopatric speciation following the colonization of a newly isolated region. Our results underscore the affinities between continental Africa and Madagascar's montane floras. The main radiations of *Helichrysum* in Madagascar's mountains occurred within the last 2 My, coinciding with a transition towards a cool, arid climate and the expansion of open habitats, and were likely driven by a combination of allopatric and ecological speciation.

### S.236.2 Evaluating the role of evolutionary processes in the differentiation of Dendrosenecio species from Mount Kenya

Juan M. Gorospe¹,², Eliška Záveská²,
Desalegn Chala³, Abel Gizaw³,
Lubomír Piálek⁴, Filip Kolář¹,²,³, Christian
Brochmann³, Roswitha Schmickl¹,²

1 Charles University, Prague, Czech Republic. 2 Institute of Botany of The Czech Academy of Sciences, Průhonice, Czech Republic. 3 University of Oslo, Oslo, Norway. 4 University of South Bohemia, Ceske Budejovice, Czech Republic.

Mountains are dynamic regions that undergo tectonic, erosional and climatic processes over a short geological time period. These processes make mountainous regions highly heterogeneous environments with a wide variety of topographic features. Such habitat heterogeneity and dynamics generate increased opportunities for lineage differentiation through ecological adaptation, geographic isolation and secondary contact. The afroalpine vegetation belts on the top of the East African mountains are highly isolated both

geographically and ecologically, which makes them a great system to study evolution and speciation. The genus *Dendrosenecio* evolved independently in four geographically isolated afroalpine mountain groups, mainly as a consequence of reduced gene flow between these mountain groups. At the same time, populations of different *Dendrosenecio* species are sometimes found in sympatry, which could be evidence for ecological speciation. In this study, we focus on two sister species, *D. keniensis* and *D. keniodendron*, that likely evolved on Mount Kenya and show clear differences in morphology, flower phenology, reproduction and ecology. These species can be found growing sympatrically, and the existence of a hybrid zone has been reported. We employed vegetation plot information and dd-RADseq data together with population genomic tools to evaluate the extent of habitat differences, genetic differentiation, and the demographic processes involved in the divergence between these two species. In particular, habitat similarity between the two species on Mount Kenya were analysed, genetic differentiation between them was evaluated, and ecological speciation was tested against geographic speciation followed by secondary contact. Vegetation plot data showed a negative relationship between both species, genetic differentiation supported two well differentiated groups, and demographic modeling supported a speciation-with-gene flow scenario. Taken together, these results suggest that ecologically mediated speciation occurred between these two *Dendrosenecio* species from Mt. Kenya.

### S.236.3 Pleistocene climatic cycles, landscape dynamics and the late rise of sky island vegetation in the Alps

Lara Wootton¹, Florian Boucher¹, Sébastien Lavergne¹

1 Université Grenoble-Alpes, France.

How past orogeny, landscape dynamics and climate change drove the emergence of species-rich mountain floras remains poorly understood. Here, we aim to uncover how the physical history of a range influences the assembly of its biodiversity in the context of the European Alpine sky island (ASI) flora. Using newly sequenced chloroplast genomes for 96% of the flora, we reconstruct a time-calibrated phylogenetic tree to infer temporal changes in assembly rates. We show that the majority of the flora assembled via col-
onisation rather than diversification, and experi-
enced high rates of extinction over the course of
its evolution. The accumulation of extant lineages
was decoupled from major orogenic events, such
as the initial uplift of the Alps and the later rise of
the peripheral massifs. Most ASI lineages instead
originated within the last 5 Myr. The Quaternary
climate oscillations had the strongest impact on
colonisation and diversification rates, which in-
creased substantially during the Pleistocene gla-
cial cycles. A search of existing biogeographic lit-
erature showed that many ASI lineages originated
locally in Europe, rather than through long distance
dispersal from temperate Asian ranges. We con-
clude that the ASI flora consists of a continuous
subset of the European flora, potentially filtered by
the ability to disperse into the sky islands after the
disturbance of the Pleistocene glacial cycles. Our
findings contradict established theories of Alpine
plant biogeography, likely because by analysing
the entire flora we include species-poor lineages
that comprise an overlooked, but important, com-
ponent of the flora.

S.236.4 Post-glacial
expansion patterns and
hotspots of intraspecific
diversity for high elevation
plants in the Pyrenees: a
multi-species

Pau Carnicero¹, Stefan dullinger², Peter Schönswetter¹

1 Department of Botany, University of Innsbruck, Innsbruck, Austria. 2 2Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.

The urgent need for preserving biodiversity is be-
yond any doubt. However, not all components of
biodiversity are usually taken into account. For
a long time, conservation efforts have targeted
ecosystems or species; in recent years, a new
focus has been put on cryptic intraspecific di-
versity on the gene level. In mountain ranges of
the temperate regions, intraspecific diversity has
been strongly determined by the Pleistocene gla-
ciation cycles. We here focus on the Pyrenees, a
hotspot of plant diversity in western Europe with
more than 4,300 plant species, but still lacking
an assessment of intraspecific diversity features.
We aimed to reconstruct the response of alpine

plants to the last glacial period and to identify ar-
eas of high intraspecific phylogenetic endemism,
which are ultimately of special interest for con-
servation. For this purpose, we used a multi-spe-
cies comparative phylogeography approach
combining molecular data (RADseq) and retro-
spective as well as prospective distribution mod-
elling of species and intraspecific lineages. Our
results show a highly structured distribution of
intraspecific diversity, which allows to formulate
the first molecular-based hypothesis of glacial
refugia for alpine plants in the Pyrenees. Refugia
of calcicolous species were in weakly glaciated
ranges south of the main chain, while silicicolous
species show a pattern of multiple geographi-
cally incongruent genetic groups, indicative of
species-specific reduced size refugia and nun-
atak survival. The easternmost Pyrenees emerge
as a common refugium for most of the studied
species and contain high levels of phylogenetic
endemism, rendering them an area of major in-
terest for conservation of intraspecific diversity.

S.236.5 Interglacial refugia shape the distribution of apomict allopolyploid Hieracium halleri on European 'sky-islands'

Shook Ling Low¹, Yann J.K. Bertrand¹, Simon V. Corrales¹, Eliška Záveská¹, Vojtěch Zeisek¹,², Begoña Quirós-de-la-Peña¹,², Patrik Mráz², Jindřich Chrtek¹,²

1 Institute of Botany, Czech Academy of Scienc-
es, Průhonice, Czechia. 2 Department of Botany,
Charles University, Prague, Czechia.

Interglacial refugia serve as counterpoint to gla-
cial refugia for cold-adapted species widely dis-
tributed during the glacial maxima but forced to
retreat due to changing climatic conditions and
increasing competition from new immigrants
during interglacial periods. European 'sky islands'
function as climate refugia for many hybridoge-
neous species whose origin might be clouded
by demographic processes like founder effect,
bottleneck, selection and genetic drift. Yet in al-
lopyploid apomictic species, i.e., hybridoge-
neous species which reproduce by seeds without
fertilization, severe gene flow reduction and few
meiotic rearrangements, preserve the progenitor
<figure><img src="image_550.png" /></figure>

genotypes and therefore allows for exploring pre-
vious contacts and subsequent local extinctions
of their parental lineages. We explored the origin,
genomic composition and post-polyploidization
population dynamics of the apomict *Hieraci-
um halleri* (triploid and tetraploid) that evolved
through hybridization between diploid *H. intyba-
ceum* (2n=18) and diploid or triploid *H. alpinum*
(2n=18, 27). We aimed to investigate the tempo
of recurrent establishment of asexual cytotypes
of *H. halleri*, elucidate whether the differences in
evolutionary histories of these cytotypes is re-
flected in their genetic variation, morphology, re-
cent distribution, and ecology. The genetic struc-
ture of hybridogeneous apomictic species and
its progenitors was explored using RADseq loci.
For the allopolyploid apomicts, haplotypes were
obtained with alignment-based phasing that
segregated data originated from the parental
subgenomes. We performed chromosome scale
assembly of one of the progenitors (*H. alpinum*,
genome size ~ 4G) and created a pseudorefer-
ence for the other by RAD loci concatenation. The
repeated independent polyploidization events
were dated using whole plastome and Hybseq
low-copy nuclear genes alignments. We also
presented the read-mapping approach method
to identify subgenomes in hybrid. Thus, an inte-
grative approach allowed us to decipher evolu-
tionary history and biogeography of this widely
distributed apomict.

S.236.6 Frailejones in Sky
Islands: insights into their
evolution, biogeography,
and conservation

Mauricio Diazgranados¹, Clara Morales-Rozo²,³, Maria Pinilla Vargas⁴, Martha Kandziora⁴, Roswitha Schmickl⁴, Andrea L. Simbaqueba⁵

1 New York Botanical Garden, Bronx, NY. 2 Pontificia Universidad Javeriana, Bogotá, Colombia. 3 Jardín Botánico de Bogotá 'José Celestino Mutis', Bogotá, Colombia. 4 Charles University, Prague, Czech Republic. 5 Universidad Pedagógica y Tecnológica de Colombia, Tunja, Colombia.

Páramos, located above the timberline in the
Tropical Andes, are remarkable examples of sky
islands, and are often considered the world's
most diverse and fastest evolving ecosystems of

the high elevations. Frailejones (common name
here referred to all the species within the Espe-
letiinae, Asteraceae), are the most representative
plants of the páramos. With circa 144 recognized
species, most endemic but locally abundant,
these plants are a model to understand not just
biogeographic and phylogenetic patterns in sky
islands, but also their conservation challenges
under the pressing world's environmental crisis.
We present the state-of-the-art regarding our
knowledge on these aspects. The most recent in-
sights into their phylogeny using Hyb-Seq on 1269
nuclear loci, support the hypothesis of two large
clades (i.e., Venezuelan and mainly Colombian
clades), radiating in the last 2.5 Ma, from Vene-
zuela into Colombia and more recently into Ec-
uador. The support for the previously established
genera is conflictive, exacerbated by the frequent
interspecific hybridization. Regarding their con-
servation status, our most recent conservation
risk assessment for Colombia suggests that 55
(61%) of the 90 species found in the country are
under threat, and 40 (45%) species are endan-
gered. *In-vitro* and *in-situ* propagation of some of
these species is underway. Based on a compre-
hensive dataset of georeferenced records (5,560
records for 138 species), we implemented the Im-
portant Plant Areas (IPAs) approach, using units
of analyses of 100 km². We identified 176 potential
IPAs using the distribution of records of globally
threatened species (including 59 species), and 51
potential IPAs when considering species richness
(including 76 species). We assessed gaps based
on currently established protected areas and
found that only 27% of the potential IPAs are with-
in those areas, and 73% face significant human
disturbances. These results inform priorities for
conserving these keystone species for the pára-
mos of the northern Tropical Andes.
# S.237 ATYPICAL SUBSTRATES FOR PLANT AND LICHEN EVOLUTION II: ULTRAMAFIC SOILS

## S.237.1 Investigating the diversity and function of microorganisms in serpentine and non-serpentine soils across California

Allie Igwe¹, Michelle Afkhami¹

1 Department of Biology, University of Miami, Miami, USA.

Serpentine soils, characterized by high heavy metal levels and magnesium-to-calcium ratios, exert selective pressure on plants and microorganisms. While some plants are endemic to these soils, most struggle to survive. Our research revealed that serpentine-indifferent plants, thriving on both serpentine and non-serpentine soils, may be sustained by their association with locally adapted plant growth-promoting bacteria. The role of microorganisms in supporting plant diversity and ecosystem services is being explored, and characterizing taxonomic and functional microbe diversity on and off serpentine soils is crucial. Our project aimed to identify taxa associated with serpentine or nonserpentine soils, characterizing microorganisms' plant-growth-promoting properties across California. Shotgun metagenomic sequencing and physiological assays were conducted on soil samples from 23 sites. Kaiju and MEGAN6 were used for taxonomic classification and functional analysis. After removing contaminants, 41,326 taxa were identified, with similar abundance and alpha diversity across serpentine and nonserpentine soils. Soil chemistry and location significantly shaped bacterial and eukaryotic communities, not archaeal ones. Random forest analysis highlighted features like Mesorhizobium, Rhizobium, and Pontibacter in nonserpentine soils and Nitrosophaera and Pontibacter in serpentine soils. Preliminary functional analysis revealed Ni/Fe subunits and siderophore production functions. Siderophore production was influenced by nickel presence, with higher levels in serpentine soils. Approximately 50% of microorganisms from both soil types fixed nitro-

gen, and 20% solubilized phosphorus. This study enhances our understanding of nutrient cycling in metal-rich, drought-prone soils, impacting plant-microbe interactions, agriculture, and bioremediation. The findings inform conservation policies, aiding efforts to preserve unique soil ecosystems and their microorganisms.

## S.237.2 How ultramafic soils can affect plant-herbivore interactions

Robert S. Boyd¹

1 Department of Biological Sciences, Auburn University, Alabama, USA.

The unique features of atypical substrates such as ultramafic soils can have important effects on organismal interactions and may provide stimulating avenues for research. Some ultramafic soil plants (metal hyperaccumulators) have extraordinarily elevated metal concentrations (most often nickel). Hyperaccumulated nickel can defend plants against some (unadapted) herbivores and therefore act as an elemental chemical defence. Elemental defences differ from more widely studied organic chemical defences because the toxin is absorbed from the soil (rather than being constructed from photosynthetic products) and an elemental defence cannot be obviated by breaking it down into constituent parts (which is one way that organic defence chemicals can be detoxified by herbivores). But some herbivores (such as the heteropteran *Melanotrichus boydi*) have apparently evolved metal tolerance and thus can feed with impunity on nickel hyperaccumulators. Elemental defences may even benefit plants that accumulate elements at levels lower than hyperaccumulation thresholds, especially if elemental defences and organic plant defences have additive or synergistic joint effects. This aspect of elemental defences needs further investigation. Plant-herbivore interactions may also influence the color of plant species growing on ultramafic soils. For example, there is a striking correspondence between substrate color and seed coat or leaf colors of some California ser-
<figure><img src="image_551.png" /></figure>

pentine plants, suggesting that visual apperency
of these plants to herbivores may drive evolution
of traits such as seed coat or leaf color. Visual
apperency may be an under-studied aspect of
plant-herbivore interactions on serpentine and
other atypical soils.

S.237.3 The diversity of mineral nutrition in a diverse shrubland on ultramafic soil is revealed through community ionomics

Yohan Pillon¹, Juliette Hocedez¹, Karine Gotty¹, Vanessa Hequet²,³, Sandrine Chay⁴, Audrey Léopold⁵, Stéphane Dray⁶

1 Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, INRAE, CIRAD, Institut Agro, Univ. Montpellier, Montpellier, France. 2 AMAP, IRD, CIRAD, Herbier de la Nouvelle-Calédonie, Nouméa, New Caledonia. 3 AMAP, Univ Montpellier, IRD, CIRAD, CNRS, INRAE, Montpellier, France 4 IPSIM, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France. 5 Institut Agronomique néo-Calédonien, équipe SolVeg, Nouméa, New Caledonia. 6 Université de Lyon, Université Lyon 1, CNRS, VetAgro Sup, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, France.

High species richness is observed in some shrub-
lands growing on infertile substrates. Mineral
nutrients may be the main limiting resources in
such ecosystems and underground interactions
between plants are probably a key to understand
their diversity. Here we tested whether there was
a nutritional differentiation between plant spe-
cies co-occurring in a shrubland in an edaphical-
ly extreme environment. We designed a 20 x 20 m
plot in a diverse shrubland ("maquis") on ultra-
mafic (infertile) substrate in New Caledonia. We
sampled all 475 plants taller than one meter and
we characterised their ionome (22 elements). A
total of 37 species were recorded, including a few
abundant species and many rare species, repre-
senting all major types of mycorrhizal symbioses,
nitrogen-fixing plants (actinorhizal but not Faba-
ceae), cluster rooted and parasitic plants. Both
nickel- and manganese-hyperaccumulating
species were present in the plot. Using hypervol-
ume approaches, we observed limited overlap in
the ionome of the 10 most abundant species. The
functionally most distinct species were also the
rarest ones in the plot. A diversity of nutritional

strategies was represented in the plot, as indicat-
ed by the diversity of root symbioses and differ-
ences in leaf ionomes. These special nutritional
traits associated with adaptation to the infertile
substrates meet the expectation of the theory of
the Old Climatically Buffered Infertile Landscapes
(OCBIL). Our results suggest that partitioning into
different biogeochemical niches, including highly
specialised ones, could explain the coexistence
of a large number of species in this shrubland on
infertile substrate.

S.237.4 Ophiolitic substrates as drivers for reticulate evolution in Armeria (Plumbaginaceae)?

Manuel Tiburtini¹, Salvatore Tomasello²,
Giovanni Astuti¹, Luca Sandroni¹, Thomas
Abeli³, Lorenzo Peruzzi¹

1 University of Pisa, Pisa, Italy. 2 Georg-August-Universität, Göttingen, Germany. 3 Roma Tre University, Rome, Italy.

Ultramafic substrates can play a role in foster-
ing ecological adaptation and microevolutionary
dynamics. The Italian endemic Armeria denticu-
lata complex includes two species (A. denticu-
lata and A. saviana): the former is a serpentin-o-
phyte endemic to Tuscany and western Liguria,
the latter grows on limestone/jasper in a small
area of southern Tuscany. Intriguingly, also north-
ern Apennine populations of A. arenaria sub-
sp. praecox, a subspecies otherwise endemic to
western Alps, grow on ophiolites. Finally, the cen-
tral-southern Italian endemic A. gracilis is strictly
linked to limestone. We aimed at understanding
whether substrate specificity and/or hybridiza-
tion-introgression promoted speciation in the A.
denticulata complex, despite similar ecological
conditions failed to cause speciation in the near-
by A. arenaria. We extracted DNA from two pop-
ulations of A. arenaria subsp. praecox, three of A.
denticulata, one of Armeria saviana, and one of
A. gracilis. Sequencing was conducted using ge-
nome skimming on a NovaSeq sequencer, gath-
ering about four Gb of sequence information per
sample. After quality trimming of the reads, we
performed reference-based assembly of plas-
tomes (152kb) and nrDNA (ETS+ITS+rRNA regions,
12kb altogether) to infer phylogenies. The genom-
ic data were complemented by a morphometric
<figure><img src="image_552.png" /></figure>

study using a Principal Component Analysis (134 individuals × 27 characters). Phylogenomic results suggest that *A. saviana* may have a homoploid hybrid origin involving *A. denticulatas*.str. (pollen donor) and *A. gracilis* (ovule donor), whereas a population of *A. denticulata* from inner Tuscany (Monte Ferrato) could have originated from an introgression/hybridization event between *Ame-ria denticulata* s.str. (pollen donor) and one of the haplotypes found in *A. arenaria* subsp. praecox (ovule donor). This is supported also by morpho-metric results, which highlight positions of the putative hybridogenic populations somehow intermediate between the putative parents in the morphospace. In summary, our results suggest that substrate specificity and hybridization/introgression prompted microevolutionary processes.

## S.237.5 Exploring Nutritional Strategies in the Rich Gypsophile Flora of Mexico

Juan Mota¹, Encarnación Merlo¹, Hilda Flores Olvera², Helga Ochterena Booth², Juan Pablo Ortiz-Brunel³

1 Department of Biology and Geology, CEI.MAR and CECOUAL, University of Almería, La Cañada, Almería, Spain. 2 Departamento de Botánica, Instituto de Biología, Ciudad Universitaria, Ciudad de México, Mexico. 3 Departamento de Botánica y Zoología, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan, México.

The accumulation of mineral elements in the leaves, such as S, Ca, Mg, and Sr, has been proposed as a set of important traits in gypsophile plants to cope with the edaphic and hydric stress posed by gypsisols. Mexico hosts the richest gypsophile flora globally, primarily concentrated in the Chihuahuan Desert and the Sierra Madre Oriental, although gypsum soils are scattered throughout the country. However, many functional aspects related to the adaptations of this flora remain unknown in this biodiversity hotspot, including those associated with the accumulation of the mentioned key mineral elements. To explore nutritional strategies, soil (15) and foliar (30) samples from two species of *Selaginella*, four ferns, and 24 angiosperms were collected on gypsum soils from the Valle de Tehuacán, the Sierra Madre Occidental (Colima and Jalisco), the Sierra Madre Oriental, and the Chihuahuan

Desert. Of these species, 19 are considered gypsophiles, and 11 are gypsovags (Ortiz et al. 2023). Our initial hypothesis proposed that nutritional patterns are similar among Mexican plants growing on gypsum compared to those known in the Spanish gypsicolous flora, thoroughly investigated from this point of view. Our results confirm the high values for foliar mineral contents, typical of gypsophiles and some gypsovags (Merlo et al. 2019). These findings align with the high gypsum contents of Mexican soils; in 2/3 of the cases studied, gypsum contents were higher than 90%. However, we found notably high values for S, Ca, Mg, and Sr in some of foliar samples collected in Mexico. These results are not only consistent with those found for the Spanish flora, but we also extend them to the case of ferns and lycophytes, which are studied here for the first time.

**References:** Ortiz-Brunel, J.P. et al. 2023. https://doi.org/10.3390/d15040522. Merlo, M.E. et al. 2019. https://doi.org/10.1016/j.ecolind.2018.10.001.
<figure><img src="image_553.png" /></figure>

# S.238 NEW INSIGHTS ON BIG PLANT GENERA 1: DIVERSITY & DISTRIBUTION

## S.238.1 The history of the colonization of the Southern Hemisphere by the megadiverse genus Carex L. (Cyperaceae)

Pedro Jiménez-Mejías¹, María Sanz Arnal¹, Pablo García Moro¹, Ana Morales Alonso², Carmen Acedo³, Carmen Benítez Benítez⁴, Asunción Cano⁵, Sabina Donadío⁶, Kerry Ford⁷, Raúl Lois³, Modesto Luceño¹, José Ignacio Márquez-Corro⁸, Muthama Muasya⁹, Paulo Muñoz-Schüler¹⁰, Nora Oleas¹¹, Tamara Villaverde², Karen Wilson¹², Daniel Spalink¹³, Santiago Martín-Bravo¹

1 Universidad Pablo de Olavide, Spain. 2 Universidad Rey Juan Carlos, Spain. 3 Universidad de León, Spain. 4 Universidad de Sevilla, Spain. 5 Universidad Nacional Mayor de San Marcos, Peru. 6 Instituto de Botánica Darwinion, CONICET, Argentina. 7 Manaaki Whenua - Landcare Research, New Zealand. 8 Royal Botanic Gardens, Kew, UK. 9 University of Cape Town, South Africa. 10 Universidad de Concepción, Chile. 11 Universidad Tecnológica Indoamérica, Ecuador. 12 Royal Botanic Gardens, Sydney, Australia. 13 Texas A&M University, USA.

Carex (>2,000 spp) diversity is not equally distributed across the continents. This cold-adapted genus was originated in E Asia during the Eocene, from where it expanded and diversified across the Northern Hemisphere. The colonization of the Southern Hemisphere (SH) happened from the Miocene onwards. Remarkably, the resulting diversity levels in each of the landmasses are very different. South America (SA) and New Zealand (NZ) harbor the largest diversity compared to Africa and Australia. Here we perform a continental-level comparison of Carex evolutionary history in the SH. Results indicate that all the areas were recurrently colonized by different lineages. No S migrations happened repeatedly from the Miocene to the Pleistocene, suggesting that no single bioclimatic event or colonization route were the triggers of the dispersal events. The number of groups in these areas increased towards the late Miocene, pointing that the Neogene global cooling facilitated

colonization. Most lineages appear to be ecologically pre-adapted to SH cold/temperate climates, since little differences in the bioclimatic niche is observed compared their sister groups. Africa, NZ and SA displayed a few large in-situ radiations, which entailed to some extent niche diversification. Most diversity in NZ was explained by extensive radiation of two clades, which seemingly have had a competitive exclusion effect preventing the establishment or diversification of other lineages. SA diversity is equally due to in-situ diversification and also to a number of poorly diversified groups. The higher connectivity of SA with the Northern Hemisphere, and the larger available area for Carex to diversify, explains these differences. In turn, the relatively low diversity in Australia and Africa appears to be due to the limited ecologically available area in these landmasses. Essentially the differences respond to the huge Carex diversity and its diverse natural history, involving different taxonomic groups, geoclimatic events and colonization routes.

## S.238.2 Systematics and evolution of the Euphorbiaceae giants (Croton and Euphorbia): recent findings, new insights, and current challenges

Ricarda Riina¹

1 Real Jardín Botánico, CSIC, Madrid, Spain.

The family Euphorbiaceae includes two of the most-species rich genera of flowering plants: Croton (~1,300 species) and Euphorbia (~2,060 species). Euphorbia is clearly defined by its highly specialized and unique inflorescence, the cyathium, while Croton is distinguished by a suite of morphological features. Taking their global distributions together, species of both or either of these genera are present in almost all biomes of the world. Many species are important for a variety of traditional human uses and for the development of products in the pharmaceutical and other industries. Numerous weeds and pioneer species are present in
<figure><img src="image_554.png" /></figure>

both genera, while ornamentals of high commercial
value are common in *Euphorbia*. A robust phylogenet-
ic framework is available for *Euphorbia* based on both
Sanger sequencing and genomic data. Many of the
recent advances in the systematics of *Euphorbia* have
been focused on groups or species complexes distrib-
uted in Eurasia, Macaronesia and Africa. Unlike *Euphor-
bia*, phylogenetic relationships within *Croton* remain
largely unresolved at deep and shallow nodes, but pre-
liminary analyses using genomic data (HybSeq) show
promising results for resolving the genus backbone
as well as species relationships within its main clades
or sections. Recent developments in our knowledge
of *Croton* include the discovery of new clades, clarifi-
cation of phylogenetic relationships and taxonomy of
important sections, and the increasing incorporation of
anatomical characters and development approaches
in morphological studies, including both vegetative and
floral structures. These have provided new insights into
the evolutionary success of *Croton* in arid or seasonal-
ly dry habitats, and into the evolution of chemical and
physical defenses against herbivores and pathogens.
Major gaps in the biological knowledge of the two gen-
era are highlighted, including suggestions for key ques-
tions to be addressed in future studies.

S.238.3 Why we recognize
big genera? The birth
of a big genus, Miconia
(Melastomataceae)

Fabián A. Michelangeli¹, Frank Almeda²,
Lucas Bacci³, Eldis R. Bécquer⁴, Léo-
Paul Dagallier¹, Walter S. Judd³, Renato
Goldenberg⁵, Darin S. Penneys⁶, Monique
Romeiro-Brito³, Lucas C. Majure³

¹The New York Botanical Garden, Bronx, NY, USA. ²Frank Almeda, California Academy of Sciences, San Francisco, CA, USA. ³University of Florida, Gainesville, FL, USA. ⁴Jardín Botánico Nacional-Universidad de la Habana, La Habana, CP, Cuba. ⁵Universidade Federal do Paraná, Curitiba, PR, Brazil. ⁶University of North Carolina Wilmington, Wilmington, NC, USA.

The tribe Miconieae (Melastomataceae) comprises ca.
1,900 species of Neotropical mostly shrubs and trees. For
most of the 20th century between 17 and 22 genera were
accepted in most treatments, and another ca. 12 were
often recognized in the tribe. Phylogenetic analyses, first
with a few genes and more recently with hundreds of
genes, recover *Miconia* (the largest genus with close to

1,100 species in its old definition), as paraphyletic with all other genera embedded within it. Moreover, only four traditionally recognized are recovered as monophyletic, with some, like *Leandra* and *Ossaea*, recovered in at least a dozen clades each. A search for diagnostic characters that would allow recognition of a manageable group of smaller genera have proven futile due to a series of factors: 1-node stability and support, 2-changes in resolution with the addition of taxa, 3-well conserved and diagnostic characters being impractical for taxonomy (e.g. micromorphological features of seeds or internal anatomy), 4-well-defined and supported groups contain many taxa with reversals to pleiomorphic conditions rendering diagnostic characters unusable, and 5-well-supported and diagnosable clades are embedded in larger grades. Based on these factors we have proposed an expanded *Miconia* as the only genus in the tribe. *Miconia* s.l. is the seventh largest genus of flowering plants, and notably the only one among the 10 largest whose native range is restricted to the Neotropics. Recognizing *Miconia* s.l. highlights an extraordinary radiation that occurred in a relatively short amount of time. While the advantages of recognizing a single genus outweigh the disadvantages, this decision has some drawbacks. These include the size, making it unwieldy for monographic work, and subsumption of endemic genera that may impact their utility in conservation. We discuss how these issues are shared among megadiverse genera and address different strategies for tackling them.

S.238.4 Ancient origin and
recent diversification of a
giant genus: Evolution of
Philodendron (Araceae) in
the junction zone of Central
& South America

Marco Cedeño-Fonseca¹,²,³, Orlando O. Ortiz¹,⁴,⁵, Nils Köster¹, Astrid de Mestier⁶, Thomas Borsch¹

1 Botanischer Garten und Botanisches Museum Berlin, Freie Universität Berlin, Berlin, Germany. 2 Herbario Luis Fournier Origgi (USJ), Centro de Investigación en Biodiversidad y Ecología Tropical, Universidad de Costa Rica, Apdo.11501-2060, San José, Costa Rica. 3 Jardin Botánico Lankester, Universidad de Costa Rica, Apartado 302-7050 Cartago, Costa Rica. 4 Herbario PMA, Universidad de Panamá, Panamá, Panamá. 5 Coiba Scientific Station (COIBA AIP), Panamá, Panamá. 6 Institut für
Biologie – Systematische Botanik und Pflanzengeographie, Freie Universität, Berlin, Berlin, Germany.

With >600 currently accepted species and an estimated total of 1500 species, *Philodendron* is the second largest aroid genus and one of the most diverse genera in Neotropical rainforests. It originated 29 Mya in the pan-Amazonian rainforests and diversified more intensely from the Late Miocene onwards, coinciding with the rise of the Andes and the formation of the Isthmus of Panama. Being South American in origin, the genus colonized Central America only relatively late from the Pliocene onwards. Nonetheless, the region is one of the centers of diversity and endemism of *Philodendron*, harboring >120 known species in Central America and Mexico. In all available molecular studies, however, representation of species from this region has been poor. In order to understand the evolutionary origin of the high Central American diversity, we used an exhaustive species sampling and a combination of three non-coding plastid regions (petD, rpl16, and trnK/matK). The phylogenetic results support 12 geographically well-defined clades in the large subgenus *Philodendron*, 10 of which consist of species from the Amazon, the Andes, and the Chocó Biogeographical Region. The vast majority of species from Central America, southern Mexico and the Caribbean were found in two distinctive and diverse Central American clades, apart from five smaller subclades and several single, rather widespread species nested within the South American clades. This pattern suggests at least nine colonization events in the region and several rapid radiations, especially in the Talamanca Mountain range and along the Isthmus of Panama. In summary, *Philodendron* has proven to be an ideal model group to study the historical biogeography and evolutionary processes of big plant genera in the Neotropics, the most diverse phytogeographic realm.

## S.238.5 Twenty years of big genera

Débora Zuanny¹, Domingos Cardoso¹,²,
Tiina Särkinen³, Sandra Knapp⁴, Peter W.
Moonlight⁵

1 Instituto de Biologia, Universidade Federal da Bahia, Salvador, Bahia, Brazil. 2 Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil. 3 Royal Botanic Garden Edinburgh, Scotland, UK. 4 Natural History Museum, London, England, UK. 5 Botany, School of Natural Sciences, Trinity College Dublin, Ireland.

Big plant genera are often considered the final frontier of plant systematics. Their size means that they are dif-

ficult to study in their entirety and as a consequence the taxonomy, systematics, evolutionary history, and ecology of these genera are poorly known. It is now 20 years since the last review of the history and concepts of big plant genera, when 57 such genera were recognized. There has been a proliferation in plant bioinformatics and taxonomic databases over the past 20 years, including the World Flora Online and Plants of the World Online. Here we review the current number, size, and geographic distribution of big plant genera based on the current data. We recognize 87 big plant genera, an increase of 30 genera, that collectively include 25% of all plant species. Of these genera, 28-29 are considered "megadiverse" with >1000 species each and account for 13% of all plant species. We discuss, with examples, the mechanisms behind the changes in the number and size of big and megadiverse genera since 2004. We compare the distribution of species in big plant genera to the distribution of flowering plants as a whole to demonstrate that big genera have diversified through the temperate and tropical regions of the world but are over-represented in temperate regions.

## S.238.6 The evolution of Impatiens: phylogenomics and biogeography

Nora S. Gavin-Smyth¹,², Jeremie B. Fant¹,², Patrick S. Herendeen¹,²

1 Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, Glencoe, IL, USA. 2 Plant Biology and Conservation, Northwestern University, Evanston, IL, USA.

The *Impatiens* genus is well known to vary excessively, presenting extensive modifications in floral structure among its 1200 species. Most *Impatiens* lineages radiated just within the last 3 million years, indicating that these disparate floral forms can evolve rapidly, even among closely related taxa. Phylogenetic relationships in the genus have historically been difficult to intuit based on morphology, given numerous occurrences of convergent evolution, but also difficult to determine based on molecular characters, due to issues such as incomplete lineage sorting and hybridization. We present results of the first target enrichment approach to *Impatiens* phylogeny, using Angiosperm353 loci. In our tree with over 325 individuals from 250 taxa, we focus on resolving the phylogenetic relationships among African taxa, with a fine-grain focus on the endemic-rich Eastern Arc Mountains of Tanzania and Kenya. We also recovered plastomes for these
<figure><img src="image_555.png" /></figure>

samples and estimated the chloroplast phylogeny; we found several instances of discordance with the nuclear phylogeny. In the nuclear phylogeny, we found that endemic-rich clades generally diversify within mountain units in the Eastern Arc Mountains. This indicates ecological speciation in this case,

and the important role of limited dispersal ability in *Impatiens* diversification. Conversely, we found the opposite pattern in the bird pollinated endemic-rich clades. However, the pattern for bird-pollinated taxa is not present in the chloroplast tree.

# S.239 MTZ FLORAS, A WARNING LIGHT OF GLOBAL CONSERVATION FUTURE

## S.239.1 Contrasting patterns for endangered flora revealed by 60-year land-use change analysis

Sandra Navas¹, Rut Sánchez de Dios¹, Felipe Domínguez Lozano¹

1 Department of Biodiversity, Ecology and Evolution, Complutense University of Madrid, Madrid, Spain.

Land-use change analysis is widely accepted as a biodiversity conservation tool. However, it has seldom been used in the context of endangered plants. Our aim is to accurately quantify changes in land cover over the last 60 years in a selection of 58 populations of 43 Spanish threatened plants. Consequently, we explain how these changes correlate with major trends in biodiversity conservation such as human demography, ecological gradients or the spatial distribution of plant threats. A semi-automatic classification methodology has been used to identify land-cover changes by comparing aerial photographs from 1956 to 2019 in an established radius around field plots. Secondly, information from field plots and external databases was analyzed using GIS layers and PCA statistics. Land-use changes have been extensive throughout the sampled threatened plant populations. On the one hand, we find species inhabiting mountain areas, which are less prone to land-use changes because human activities are limited. On the other hand, species that have their habitats in coastal and/or urbanized areas. Hence, land-use changes define two groups in the endangered flora: a first group is related to high human densities, low elevation settings and low in situ protection, while a second group is related to the cessation in human pressure, protected area establishment and increase in forest cover. Based on our research, it can be concluded that passive

rewilding is not the solution to conservation problems for plants, and could be counterproductive. Urban land-use changes present a more urgent issue, especially for those endangered plants in coastal areas. Finally, high herbivore density and richness compromise endangered plant populations growing at high elevation in protected areas.

## S.239.2 Quantifying the potential niches of endangered plant species for improving reintroduction success

Merav Lebel Vine¹, Jonathan Belmaker¹, Yuval Sapir¹

1 Tel Aviv University, Israel.

One of the most severe threats to global biodiversity is land-use changes. Reintroduction is a major conservation tool, but its success relies on accurate estimation of the species niche. While niche modeling has been used to predict the distribution of plants, it has been rarely used as a tool for predicting reintroduction success. We aim to examine the possible use of niche modeling for improving endangered species reintroduction success and thus contributing to plant conservation efforts. The East Mediterranean basin is a hotspot of plant diversity, but due to dense population and massive urbanization, only a small fraction of the natural areas remains, challenging the finding of appropriate sites for reintroduction. Moreover, habitat suitability is rapidly changing with global climate change. We used species distribution models (SDM) to estimate the potential niche for reintroduction of endangered species based on known sites of occurrence. Reintroduction field experiments in natural reserves and agricultural land
are currently performed for five endangered endemic plants- *Rumex aeroplaniformis*, *Verbascum berytheum*, *Salvia eigii*, *Onosma gigantea*, and *Vicia esdraeloninsis*- representing two endangered habitats: Loamy soils in valleys and coastal sandy soils. For those species, we also predicted future potential distribution using future climate projections. For all species, the model predicts a general decline in the potential distribution, particularly in the suitability of current population sites.

### S.239.3 Composition, diversity and productivity of ruderal vegetation in Mediterranean peri-urban greenspaces

Miriam García Torija¹, José R. Quintana Nieto², Raquel Pino Bodas³, José A. Molina Abril¹

1 Department of Botany, Complutense University of Madrid, Spain. 2 Department of Soil Sciences, Complutense University of Madrid, Spain. 3 Department of Botany, Rey Juan Carlos University, Madrid, Spain.

Urban ecosystems are experiencing a significant growth worldwide. Cities include areas that provide important ecosystem services such as carbon sequestration and maintenance of biodiversity. In a context of global warming, it is necessary to increase knowledge on ecosystem services provided by Mediterranean urban greenspaces. Our study was focused on spontaneous vegetation in four periurban greenspaces located in Madrid (Spain). We aimed to analyse the composition, diversity and productivity of four plant community types widely extended in Mediterranean urban areas, namely annual graminoid grasslands, annual herbaceous communities on slope roadsides, perennial herbaceous communities and perennial graminoid grasslands. Plant species composition, productivity, diversity, cover of growth forms and functional groups were determined in 3 plots x 4 plant-communities x 4 greenspaces = 40 plots analyzed. We used generalized linear model to determine the influence of the community type on vegetation variables. We performed a cluster analysis by unsupervised agglomerative classification, to test numerically the vegetation types and to identify their diagnostic, characteristic and differential species. Our results showed that perennial herbaceous communities

had a significant lower species richness in comparison to the other communities but a lower Shannon index and higher biomass when comparing them with herbaceous communities on slope roadsides and perennial graminoid grasslands. Besides, annual grasslands showed a significant higher abundance of individuals. Regarding functional groups, a significant higher cover of mucilage-accumulator plants was detected in the perennial herbaceous communities and of Sulphur-accumulator plants in the annual herbaceous communities on slope roadsides. The agglomerative classification identified two sub-communities within the vegetation type on slope roadsides. We conclude that plant productivity, diversity, and cover of functional groups and their associated ecosystems services, are unevenly distributed throughout urban greenspaces. Furthermore, their management should be addressed to preserve those vegetation types that better support biodiversity and carbon storage.

### S.239.4 Regional application of a global conservation approach: spatial patterns of EDGE angiosperms in the Iberian Peninsula

Ignacio Ramos-Gutiérrez¹,²,³, Sebastian Pipins²,⁴,⁵, Rafael Molina-Venegas³,⁶, Mario Fernández-Mazuecos¹,³, Pedro Jiménez-Mejías⁷, Juan Carlos Moreno Saiz¹,³, Félix Forest²

1 Department of Biology (Botany), Universidad Autónoma de Madrid, Madrid, Spain. 2 Royal Botanic Gardens, Kew, Richmond, UK. 3 Centro de Investigación en Biodiversidad y Cambio Global (UAM), Spain 4. Department of Life Sciences, Imperial College, London, UK. 5 On the Edge, London, UK. 6 Department of Ecology, Universidad Autónoma de Madrid, Madrid, Spain. 7 Department of Molecular Biology and Biochemical Engineering (Botany), Universidad Pablo de Olavide, Seville, Spain.

Determining the species or regions to prioritize for preservation stands as a key topic in Conservation Biology. Traditionally, this assessment relies on specific criteria such as the threat risk to a particular taxon or the richness of species for defining protected areas. However, incorporating an evolutionary variable into these analyses can be achieved through the utilization of mega-phylogenies. The EDGE (Evolutionarily Distinct and Globally Endan-
gered) metric combines how evolutionary unique a species is, along with how likely it is to become extinct. Thus, a comprehensive global EDGE analysis allows the creation of a priority list, offering a quantitative measure of the importance of preserving each individual species. The Iberian Peninsula is a major center of plant richness and endemism within the Mediterranean hotspot, and the recent publication of the AFLIBER atlas with the distributions of all Iberian angiosperms using a 10 km grid, enabled the use of an EDGE analysis for the first time for a regional flora. We then determined which areas presented a higher conservation value, calculated as the sum of the EDGE scores of all occurring species in each area. Lastly, a prioritization list of areas for preservation was established using complementarity methods, maximizing EDGE conservation in a minimum area. Many selected areas were located in coastal or mountainous enclaves, often absent from national networks of protected spaces.

## S.239.5 MTZ (MTE, Mediterranean type zones) floras, a warning light of global conservation future

Andrés Moreira-Muñoz¹, Anthony G. Rebelo², Felipe Domínguez Lozano³

1 Instituto de Geografía. Pontificia Universidad Católica de Valparaíso Valparaíso, Chile. 2 South African National Biodiversity Institute, Kirstenbosch National Botanical Garden Rhodes Dr, Newlands, Cape Town, South Africa. 3 Fac. Biología, Universidad Complutense de Madrid, Madrid, Spain.

MTZ combines three main aspects basic in conservation science, biodiversity, threats and knowledge. It is one of the richest and highly diverse biome in the Globe, the most if we consider area extension. In addition, the MTZ floras are extensively studied and well known. Finally, MTZ has been for long, one of the more intensive conservation scenarios. We address two major points: **First, we review major current drivers of threats. We provide an update on some of the most acknowledged plant conservation problems**, such as land use changes (urbanization), fire, or herbivory. We also review the red list plants assessments in MTZ. **Then, we carry on a future prospect of conservation mediterranean plants, addressing future scenarios of conservation efforts.** More specifically, we question: are different MTZ areas responding differently to common conservation

challenges? For that we explore trends in extinction rates and threatening processes, delineating what types of plants are becoming more threatened and why. This will allow us to identify possible conservation gaps in plant conservation. We also deal with future trends in protected areas: National Parks, microreserves and urban areas in relationship with plant conservation.

Finally, we introduce flora rewilding as a restoration approach for plant conservation. We identify some current and future projects. We propose some tools for a global system of plant biodiversity and conservation monitoring in the five MTZ.

## S.239.6 200 years evolution of an urban remnant habitat

Rut Sánchez de Dios¹, Pablo Castro Sánchez-Bermejo²,³, Ignacio Mola⁴, Felipe Domínguez Lozano¹

1 Department of Biodiversity, Ecology and Evolution, Faculty of Biological Sciences. Complutense University of Madrid. 2 Institute of Biology/Geobotany and Botanical Garden, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany. 3 German Centre for Integrative Biodiversity Research, Halle-Jena-Leipzig, Leipzig, Germany. 4 Independent consultant.

Urban biodiversity is originated by the curse of urban history, biogeographical context, and disturbance regime. Therefore, several species groups and functionalities conform present urban biotas, conforming a mixture of novel ecosystems and remnants of natural habitats. Recently, urban settings have been considered perfect scenarios to develop nature conservation and restoration actions. However, because of this mixed origin and rapid changes, the frontier between nature and cultural conservation may be fuzzy and true conservation measures could be mistaken for traditional horticultural practices. The study of the evolution of remnant natural habitats immersed in the urban matrix can contribute to clarify future trends of urban biodiversity conservation. We hypothesized that urban remnants evolve differently than the rest of urban green habitats by maintaining, not also more species diversity, but also better functionality. Further, they may respond in different ways to urban perturbations. Our main objectives are: (i) To record gain and losses for native and non-native plants for a 200-year period in a remnant habitat, Casa de Campo (Madrid), and to compare it with the rest of urban green habitats.
(ii) To study rare- common species conformation during this period. (iii) To study functional diversity and functional spectrum. By compiling plant records from different inventories performed in Casa de Campo and Madrid during the last 200 years, we

recorded losses and gains of species (discovery and extinction rates) in both Casa de Campo and the rest of the city and simulated how different scenarios of plant species change may affect functional diversity in the remnant habitat and its surroundings.

# S.240 INTERDISCIPLINARY APPROACHES IN THE VISUAL ARTS AND THE BOTANICAL SCIENCES

## S.240.1 "Iconotypes" at the Natural History Museum Vienna and the importance of color systems, such as those utilized by Ferdinand Bauer

Tanja M. Schuster¹, Mario-Dominik Riedl¹,
Sarah M. Fiedler¹, Martin Krenn¹, Heimo
Rainer¹, David J. Mabberley²,³,⁴

1 Natural History Museum Vienna, Vienna, Austria. 2 Wadham College, University of Oxford, Oxford, UK. 3 School of Natural Sciences, Macquarie University, Sydney, Australia. 4 Australian Institute of Botanical Science, Royal Botanic Gardens and Domain Trust, Sydney, Australia.

Aside from the more commonly selected herbarium specimens for this purpose, a botanical illustration, in particular a historical one, can also serve as type for the name of a taxon. Although the term "iconotype" is not formally used in the International Code of Nomenclature for Algae, Fungi, and Plants, it is generally understood to be an illustration that serves as the type for the name of a taxon. For example, the lectotypes of many Linnaean binomials are illustrations. When a type specimen is lost or destroyed, illustrations prepared from the original material can be candidates for types; such illustrations are obligate lectotypes when all other original material has been lost. The Archive for the History of Science at the Natural History Museum Vienna holds many such "iconotypes." These include illustrations used in Jacquin's, Schott's, and others' taxon descriptions. Use of illustrations as types is facilitated if they were made using standardized coloration. An outstanding example of this is the work of Ferdinand Lucas Bauer. Bauer's

pencil field-sketches, now almost all at the Natural History Museum Vienna, were the bases for colored illustrations (mostly now at The Natural History Museum London), some of which are types. The drawings are important, as they include information omitted from the final, colored illustrations, such as collection localities, dates, and additional detailed sketches of descriptive morphological characters. The field drawings enabled Bauer to produce colored plates of exceptional aesthetic and scientific quality by employing numerical and other codes, which indicate the hue, brightness, opacity, and texture of particular parts of the living organism.

## S.240.2 Botanical motifs in the visual arts in China: an alternative look at nature

Jordi López-Pujol¹, Neus Nualart¹

1 Botanical Institute of Barcelona (CSIC-CMCNB), Barcelona, Spain.

It is well known that plant elements (flowers, leaves, fruits, but also whole plants) are a recurring motif in the different expressions of visual art (mainly painting, ceramics, sculpture and architecture) in most cultures and civilizations. In the case of East Asian countries (China, Korea and Japan) botanical motifs have an even more evident weight in their art, mainly due to the dominant religion and philosophy (mainly Taoism, Buddhism and Shintoism) in which nature and respect for it is a common thread of many of their principles. In this contribution we are focusing on the case of China, a place where "artistic botany" reached its maximum expression thanks, most likely, to the astonishing wealth of plant species and different landscapes that the country houses. This great diversity may have constituted a substrate and at the same time a cat-
<figure><img src="image_556.png" /></figure>

alyst for the rooting of beliefs and precepts in harmo-
ny with nature and, in turn, a source of inspiration for
artists. Some examples of plant motifs used profusely
in Chinese visual art will be presented, corresponding
to various historical periods, including Buddhist, Tao-
ist and Confucian symbols. These will be used as ve-
hicles through which we analyze China's flora from a
scientific point of view, both in aspects of diversity and
conservation. Finally, the possibilities offered by the
resurgence of Buddhism and Taoism in China for the
conservation of its biodiversity will be also discussed.

### S.240.3 Kaleidoscope Science: using herbarium specimens, scientific illustrations, and printmaking to provide a holistic perspective on nature

Erin Bentley¹,², Dr. David Tank¹,², Bailey Russel³, Lars Roeder³, Rebecca Austin³,⁴

1 Program in Ecology and Evolution, Department of Botany, University of Wyoming, Laramie, WY, USA. 2 Rocky Mountain Herbarium, Laramie, WY, USA. 3 Visual Arts Department, University of Wyoming, Laramie, WY, USA. 4 Makerspace Wyrkshop, University of Wyoming, Laramie, WY, USA.

Transdisciplinary approaches to science, specifically science/art, increase student learning and engagement and retain underrepresented groups in STEM, and using art to engage the public has been the source of many broader impacts. An area of transdisciplinarity that is understudied and underutilized is embracing our “transdisciplinary self”. People are multifaceted, from their biology to their culture. However, we often find ourselves in a self or socially enforced silo. This is common in science, where specialization isolates disciplines, ways of thought, and collaboration. Instead of dividing ourselves into categories like “scientist,” “artist,” “student,” “gamer,” “teacher,” we should be embracing all of them to inform our “transdisciplinary self.” By bringing our whole selves to our research, outreach, and teaching, we produce more meaningful outcomes. Through my experiences leading National Science Foundation funded science art outreach projects, conducting scholarship of teaching and learning research, and developing my artistic practice, I understand that by being our transdisciplinary selves, we

make science art that achieves more than just communication. To accomplish this, I worked with Visual Arts faculty at the University of Wyoming to develop a project that exemplifies the idea of the transdisciplinary self. Kaleidoscope Science is a science art outreach project using photo processes and printmaking to showcase the complexity of native organisms. These organisms are viewed through many lenses to generate a holistic perspective of their ecology, natural history, traditional knowledge, and other perspectives. To highlight the different aspects of each organism, we pair a screen print designed in a certain color/set of colors with a corresponding perspective and expert narrative. The final product is similar to Andy Warhol's "Self Portrait," and can be used in schools, institutions, and by researchers to gain insightful perspectives on organisms and the complexity of research, themselves, and the benefits of the transdisciplinary self.

### S.240.4 Personal practices in the integration of art and science

Nicolette Sipperly¹

1 Department of Ecology and Evolution, Stony Brook University, New York, USA.

Unification of art and science has largely been accepted in the scientific community as a way for scientists to hone in on communication skills and be able to share their science more broadly. However, I argue that there are greater implications integrating art and science process. During this presentation will share how it became essential for me to make art to explore my personal experiences alongside my work crafting my dissertation. For example, through this process I found the ways that looking at my emotional experience and personal growth with a scientific attention to detail and curiosity allowed me to overcome difficult interaction; to take ownership for my emotions rather than attempting to control the emotions of others. I share the how I consciously bringing my heart into science helped me find (or rise again after failing to find!) the notoriously elusive plants I study while navigating summers in the Rocky Mountains from Idaho to New Mexico solo. Finally, I share how devoting my final field season to water color portraits of my study group taught me more about the environments I studied than
<figure><img src="image_557.png" /></figure>

past seasons driven by my rush to collect data. By allowing awareness of my emotions to be present in science, I found I was able to connect to my work more honestly and with less resistance to failed expectations. Most importantly, I found beauty in and purpose for my unique strengths. Without taking into account emotional reality, science will perpetuate the disconnect between humans and the natural world that is made undeniable in the depletion of our world's soils, dramatic loss of biodiversity and in the always rising rates of depression and anxiety. However, if we embrace and move forward without rejecting any parts of ourselves, we can mend our relationships by connecting to human creativity.

## S.240.5 How Do We Learn to Love Learning? Using Art and Creativity to Facilitate Paleobotanical Outreach

Ashley Hamersma¹

1 Florida Museum of Natural History, University of Florida, Gainesville, USA.

What makes an educational experience memorable? How can education be individually relevant to students while maintaining quality and consistency? Can we as educators utilize our distinctive experiences to inform more effective communication? Developing outreach and teaching materials and habits is a lifelong and adaptive learning process, often through which we reach a main goal of scientific communication. In this discussion, I explore relevant methods incorporating interactive creativity used to foster engagement and understanding between scientist and audience, be that in the classroom or other settings we find ourselves in. I include my experiences in these roles and discuss responsibilities to and results from different creative learning experiences I have facilitated throughout my time as an educator, and directions of interest for future work. As scientists and educators, we are situated where our connections to both roles require us to explore the most effective ways to communicate concepts to colleagues, students, and the general public. In recognizing the role our own perspectives and skills play in our teaching and communication, it is increasingly possible to utilize those differences to teach in a unique and effective way.

## S.240.6 Field Notes

Andrew L. Hipp¹,², Rachel D Davis³

1 Center for Tree Science and Herbarium, The Morton Arboretum, Lisle, Illinois, USA. 2 Committee on Evolutionary Biology, University of Chicago, Chicago, Illinois, USA. 3 Independent Artist, artbumble.com, Downers Grove, Illinois, USA.

The of this talk have been collaborating formally as artist (RD) and writer (AH) for more than 20 years. We have published a book and several illustrated natural essays together, and we have a book in press. We are currently working on a series of paintings and essays based on the lakes of Northern Wisconsin, supported by a multiyear residency through the Drawing Water Program at UW Madison's Trout Lake Station. We collaborate at the interface between art, literature, science, and natural history. Our work is in part documentary: we take great pleasure in seeing and recording what the natural world presents us, then sharing it in our own ways. We each see an organism from a different angle, see something the other could not have. The collaboration moves beyond documenting and telling *about*, however. It also informs our individual work in art, education, and science. For Andrew, writing mediates between subjects of inquiry in the field and herbarium—a weevil escaping from an acorn, an early-emerging false rue anemone—and the processes that connect individual organisms. Sentences convey information, but they also give form to understanding. The writing is the thinking, not simply an account of thoughts. For Rachel, photographing plants, fungi and insects is a first step to discovering the formal in the natural. Painting, drawing, natural dyes, and printmaking are ways to distill the shapes of plants, the light reflected off the water, mosses seen through a magnifying lens, and lichens into patterns. The rearrangement of shapes from the landscape with colors found in nature engages and feeds her as an artist. Our talk will illustrate how this collaboration both reveals and exists in parallel with the natural world, while presenting our understanding of how integrating art, science, and natural history has changed our respective practices.
# S.241 ECOSYSTEM GENOMICS: ELUCIDATING THE GENETIC DRIVERS OF NUTRIENT FLUXES IN BRYOPHYTE DOMINATED COMMUNITIES

## S.241.1 Mosses as hosts to nitrogen-fixing cyanobacteria: abiotic and biotic controls

Kathrin Rousk¹

1 Department of Biology, Center for Volatile Interactions, VOLT, University of Copenhagen, Denmark.

Nitrogen (N) fixation by moss-associated cyanobacteria is the main source of new N in pristine ecosystems such as arctic tundra, boreal forests, and tropical cloud forests. While we have a good understanding of individual factors (e.g. temperature, humidity) that drive this ecosystem process, we still lack a comprehensive framework that can answer key questions in biogeochemistry, symbioses and ecophysiology research. Here, I present N fixation data from various environmental gradients (and thereby the combined effects of various factors), ranging from altitudinal to nutrient availability gradients, as well as moss hosts to synthesize current knowledge on moss-associated N fixation. For instance, N fixation decreased with elevation along a tropical forest mountain, linked to sharp declines in air temperature, relative humidity as well as shifts in bacterial communities associated with mosses. Nitrogen availability or pollution is another key driver of moss-associated N fixation, with inhibiting effects along natural N fertility gradients as well as in laboratory settings. In contrast, heavy metal pollution seems to be less detrimental. Whether moss host or the habitat drives bacterial communities on mosses, and thereby, N fixation rates, is an ongoing debate, and I bring new data to the debate.

## S.241.2 Variation in volatile organic compound emissions and nitrogen fixation rates from subarctic cryptogams and associated microbes.

Annika Engroff¹, Wanying Zhang¹,², Kathrin Rousk¹

1 Center for Volatile Interactions, Department of Biology, University of Copenhagen, Copenhagen, Denmark. 2 School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui, China.

Cryptogams can be significant emitters of volatile organic compounds (VOCs). VOCs are highly reactive, can considerably affect atmospheric chemistry and lead to positive and negative climate feedback. Simultaneously, cryptogams associate with microbes, especially nitrogen (N)-fixing cyanobacteria. Cyanobacteria can contribute to N-budget of the plant host as well as of the ecosystem. Besides their contribution to the N cycle, these microbes could contribute substantially to VOC emissions measured from cryptogams. However, their contribution has not been assessed to date, and a potential link to N fixation, albeit plausible, is similarly unknown. In this study, VOC emission and N fixation rates of several cryptogamic species were measured. Four moss species (*Hylocomium splendens*, *Sphagnum spp.*, *Pleurozium schreberii*, *Polytrichum commune*), three lichen species (*Peltigera aphtosa*, *Nephrona arcticum*, *Cladonia spp.*) and one liverwort species (*Lophozia lycopodioides*) from subarctic tundra were investigated before and after removal of associated microbes. Removal of associated microbes was done by surface sterilizing. VOC emissions were measured using real time PTR-ToF-MS and GC-MS. N fixation rates were measured using the acetylene reduction assay (ARA) as a measure of nitrogenase activity. Results revealed statistically significant
ly lower N fixation rates in washed compared to control condition in *Hylocomium splendens* and *Polytrichum commune*. Of all cryptograms in this study, N fixation rates were highest in the lichens *Peltigera aphtosa* and *Nephrona arcticum* and lowest in the liverwort *Lophozia lycopodioides* but without significant differences between control and washed condition. This lack of effect to surface sterilization on N fixation could be due to various reasons such as cyanobacteria residing safely within the plant cell or generally low colonization of some species. Preliminary data shows VOC emission rate and blend differences among cryptogam species as well as a positive link to N fixation rates.

### S.241.3 The molecular ecology of moss-cyanobacteria symbioses

Danillo Oliveira Alvarenga¹, Lina Ávila Clasen¹, Rune Fromm Andersen¹, Kathrin Rousk¹

1 Department of Biology, University of Copenhagen, Denmark. 2 Center for Volatile Interactions, University of Copenhagen, Denmark.

Cyanobacteria are oxygenic photoautotrophs that are widely known for releasing potent toxins in water bodies, contributing to global oxygen production and playing an important part in the evolution of life on the planet. Nevertheless, nitrogen-fixing cyanobacteria also perform a vital ecological role in the nitrogen cycle of several aquatic and terrestrial ecosystems, either as free-living organisms or in symbiotic relationships. Several plants from tropical, temperate and boreal environments were shown to recruit cyanobacteria as epiphytic symbionts when going through nitrogen starvation. This includes mosses, non-vascular plants that are usually found in moist and shaded areas. These bryophytes can be responsible for up to 100% of primary production in some pristine northern ecosystems, in which 50% of the nitrogen input may derive from moss-cyanobacteria associations. Moss-cyanobacteria interactions have consequences on a global scale, since northern environments sequester 20% of all the carbon generated by forests in the world and stock at least 32% of global terrestrial carbon. Nevertheless, few is known about how mosses can influence the physiology

and nitrogen-fixing activities of these microorganisms. Information is also lacking about the importance and dynamics of moss-cyanobacteria interactions in tropical ecosystems and how they will be directly or indirectly affected by climate change. In this presentation, I explore advances on the molecular aspects of ecological interactions between mosses and cyanobacteria in northern and tropical ecosystems. Our results suggest that mosses from different environments are potentially capable of manipulating the morphophysiology of cyanobionts to increase their N fixation rates, but without necessarily giving cyanobacteria something in return.

### S.241.4 The evolutionary origin of gene networks regulating mutualistic plant-microbe interactions

Yuling Yue¹,², Anna Neubauer¹,², Gaurav Sablok³, Jaakko Hyvönen³, Péter Szövényi¹,²

1 Department of Systematic and Evolutionary botany, University of Zurich, Switzerland. 2 Zurich-Basel Plant Science Center, Zurich, Switzerland. 3 Faculty of Biological and Environmental Science, University of Helsinki, Helsinki, Finland.

It was proposed that the molecular network enabling and controlling intimate plant-microbe symbiotic interactions could have evolved from a general starvation response. Molecules released during starvation by the host plants could have been recruited by microbes to recognize the plant host and the ancestral starvation network of the host plant could have been extended with components enabling proper control of the symbiotic interaction. Nevertheless, this hypothesis remains largely untested because information on the consequences of nutrient starvation is mainly available for vascular plants but missing for most non-vascular plant lineages. Here we investigated this hypothesis by exploring gene expression changes during nitrogen starvation in the two major lineages of bryophytes, hornworts and liverworts, capable of establishing intimate symbiotic interaction with cyanobacteria. By conducting comparative analyses with symbiotic and non-symbiotic vascular as well as non-vascular plants we found that the global gene expression response to nitrogen starvation is high-
<figure><img src="image_558.png" /></figure>

ly conserved across bryophytes and vascular plants. Furthermore, we observed little difference in response to nitrogen starvation in symbiotic and non-symbiotic species and between species establishing symbiosis with AM fungi, nodule forming bacteria or cyanobacteria. These observations suggest that the nitrogen and general nutrient starvation response is highly conserved across the two major lineages of land plants the vascular plants and the bryophytes and likely represents a starvation response inherited from their common ancestor. While the overall starvation response was conserved, we were also able to identify pathways and molecule groups only induced in the cyanobacteria-hosting bryophyte species implying their potentially role in attracting the symbionts in the initial phase of the symbiosis. Overall, our results are in line with the proposed hypothesis and suggest that regulatory gene networks governing the intimate symbiotic interaction between plants and microbes have likely evolved from a conserved starvation response involving few regulatory changes.

### S.241.5 A laboratory-to-field approach for determining the genetic and environmental factors underlying mutualism within a Sphagnum peatland system

David J. Weston¹, Alyssa Carrell¹, Jun Hyung Lee¹, Sara Jawdy¹, Dale Pelletier¹, Jon Shaw², Gustaf Granath³, Adam Healey⁴, Jeremy Schmutz⁴

1 Oak Ridge National Laboratory, Oak Ridge, TN. 2 Duke University, Durham NC. 3 Uppsala University, Sweden. 4 Joint Genome Institute, Walnut Creek, California, USA.

The importance of plant-microbiome systems on terrestrial carbon and nitrogen processes is perhaps most pronounced in Sphagnum dominated ecosystems, which occupy 3% of the Earth's land surface yet store approximately 30% of terrestrial carbon as recalcitrant organic matter (i.e., peat). The foundation plant Sphagnum is responsible for much of the primary production in peatland ecosystems and produces recalcitrant dead organic

matter. Sphagnum together with associated microorganisms, contributes substantial nitrogen inputs into peatlands and influences host resilience to extreme climatic events. Under changing environmental conditions, a central question about these ecosystems is whether the Sphagnum-microbiome will maintain its beneficial interactions, or will it shift to neutral or even antagonistic interactions that ultimately influence peatland carbon gain and storage. Here, we test the hypothesis that the thermal origin of the microbiome influence Sphagnum host performance and resilience to warming. Briefly, we mechanically separated the microbiome from Sphagnum plants residing in a whole ecosystem warming study, transferred the component microbes to germ-free plants, and exposed the new hosts to temperature stress. Although warming decreased plant photosynthesis and growth in germ-free plants, the addition of a microbiome from a thermal origin that matched the experimental temperature completely restored plants to their pre-warming growth rates. Metagenome and metatranscriptome analyses revealed that warming altered microbial community structure, including the composition of key cyanobacteria symbionts, in a manner that induced the plant heat shock response, especially the Hsp70 family and jasmonic acid production. The plant heat shock response could be induced even without warming, suggesting that the warming-origin microbiome provided the host plant with thermal preconditioning. Together, our findings show that the microbiome can transmit thermotolerant phenotypes to host plants, providing a valuable strategy for rapidly responding to environmental change.
# S.242 DYSPLOIDY, DIPLOIDISATION AND DIVERSIFICATION: IMPACT OF POST-POLYPLOID GENOME RESTRUCTURING ON SPECIES AND TRAIT DIVERSITY. SESSION 1

## S.242.1 Post-polyploid diploidization and diversification through dysploid changes

Terezie Mandáková¹

¹Central European Institute of Technology, Masaryk University, Brno, Czech Republic.

Whole-genome duplications are pervasive across land plant phylogenies, with pronounced frequency in ferns and angiosperms. These duplications have been instrumental in propelling the evolution of key innovations, fostering diversification within numerous angiosperm clades and lineages. Notably, diversification is not instigated by genome doubling itself. Instead, the differentiation of primary polyploid populations, facilitated by various processes, culminates in post-polyploid genome diploidization. Structural diploidization orchestrates a gradual reversion of the polyploid genome to a functionally diploid-like state through frequent chromosomal rearrangements, giving rise to dysploid changes. These alterations, in turn, hold the potential to induce reproductive isolation among post-polyploid offspring, significantly contributing to speciation and cladogenetic events. This intricate interplay between genome dynamics and evolutionary outcomes underscores the importance of understanding the role of post-polyploid diploidization in shaping plant diversity.

## S.242.2 Recurrent polyploidy, dysploidy, genome restructuring and ecological success in Sporobolus sect. Spartina (Chloridoideae, Poacea)

Armel Salmon¹, Lin-Feng Li², Morgane Milin¹, Yan Hao², Armand Cavé-Radet¹, Delphine Giraud¹, Oscar Lima¹, Virginie Huteau³, Olivier Coriton³, JM Aury⁴, P. Wincker⁴, Bo Li², Malika Ainouche¹

¹Université de Rennes, UMR CNRS 6553, Ecosystèmes-Biodiversité-Evolution, OSUR, Campus de Beaulieu, Rennes, France. ²Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Center for Evolutionary Biology, Fudan University, Shanghai, China. ³Plateforme de cytogénétique moléculaire végétale, Institut de Génétique, Environnement et Protection des Planetes, INRA Domaine de la Motte, Le Rheu. ⁴Genoscope, Institut de biologie François-Jacob, Commissariat à l'Energie Atomique CEA, Université Paris-Saclay, Evry, France.

Polyploidy and genome evolution are particularly well documented in the grass family (Poaceae), although the accumulated knowledge is concentrated in subfamilies containing important crop species such as rice (Oryzoideae), maize, Sorghum (Panicoideae) or wheat (Pooideae) and related species. In contrast, one of the largest, and highly variable subfamily (notably with regard to base chromosome number and ploidy levels), Chloridoideae, is still underinvestigated. We focused on the large *Sporobolus* genus where various basic chromosome numbers are recorded (n=7, 8, 9, 10). In this genus, *S. sect. Spartina* (Schreb.) P.M.Peterson & Saarela is a monophyletic clade that represents an iconic model system in evolutionary ecology. It contains several species that are considered as ecosystem engineers on coastal saltmarshes, and
some of them are highly invasive, having expanded on different continents. Of particular interest is the textbook example of neopolyploidy involving hybridization in Europe between the native *Sporobolus maritimus* (presumed hexaploid with 2n=60) and introduced American *S. alterniflorus* (2n=62) during the 19th century. Genome duplication of the sterile hybrid *S. x townsendii* (2n=62) resulted in the successful allopolyploid species *S. anglicus* (2n=124). We conducted comparative analyses involving newly *Sporobolus-Spartinaassembled* genomes and related grass genomes. We show how two successive whole genome duplication events (WGD1 & WGD2) have shaped the mesopolyploid parental genomes (chromosomal repatterning, repetitive sequence dynamics) following the diversification of the *Sporobolus-Spartina* clade in the last 20 MYs. Descending dysploidy appears to have resulted in a new base chromosome number following WGD1, which allowed us to revisit ploidy levels of the derived species. We also show how chromosomal restructuration accompanied divergence between *S. maritimus* and *S. alterniflorus* (2-5 MYA) during the speciation process and resulted in an additional chromosome pair (2n=60+2) in *S. alterniflorus*, and discuss consequences of these dramatic genome changes on species distribution and ecology.

### S.242.3 Cyto-phylogenomics of the Brachypodium grass complex unveils different pre- and post-polyploidization descending dysploidy trends

María Ángeles Decena<fnref n="1" />,², Joanna Lusinska³, Rubén Sancho<fnref n="1" />,², Robert Hasterok³, Ernesto Pérez-Collazos<fnref n="1" />,², Luís. A. Inda<fnref n="1" />,⁴, Pilar Catalán<fnref n="1" />,²

Descending dysploidy may be considered as one of the mechanisms that convert polyploids into functional diploids. However, karyotypes resulting from this mechanism can also be present in neopolyploids and diploids. The model grass genus *Brachypodium* contains up to 21 recognized species showing a remarkable descending dysploidy and various ploidy levels. We performed an extensive cyto-phylogenomic study of its 14 worldwide distributed perennial species and minor satellite taxa. Genome size, chromosome number, and comparative-chromosome-barcoding analyses across 147 populations revealed previously unknown cytotypes for several species and characterized the karyotypic profiles of their constituent genomes. A *Brachypodium* supertree showed the participation of ancestral 'orphan' progenitor genomes in American *B. mexicanum*, ancestral and recent 'orphan' and 'extant' progenitor genomes with diverse basic chromosome numbers or karyotype structure in the aridic-to-mesic Mediterranean and Western European lineages (*B. retusum*, *B. boissieri*, *B. phoenicoides*, *B. rupestre*), and intermediate-recent 'extant' progenitor genomes in currently diploid core-perennial mesic lineages (*B. arbuscula*-2x, *B. sylvaticum*-2x, *B. pinnatum*-2x). Phylogenetic inference suggested the rapid evolution of distinct descending dysploidy trends from ancestral (x=10) or intermediate (x=9) karyotypes to different sorts of derived karyotypes (x=8, x=6, x=5). Our hypothesized scenarios indicated that some of the descending dysploidies preceded both ancestral and recent polyploidizations (x=10->x=8[genome A2], x=10->x=9[G], x=10->x=5[D], x=9->x=8[E1], x=9->x=5[E2]) as these unique karyotypes correspond to orphan diploid progenitor genomes of current Brachypodium polyploids, while others likely occurred after the polyploidizations (x=8[A2]+8[E1]+5[E2]->x=8[A2]+6[E1]+5[E2]; x=9[G]+5[E2]+5[E2]->x=8[G]+5[E2]+5[E2]), as they correspond to rare orphan subgenomes of some allopolyploids. Our analysis uncovered another recent descending dysploidy (x=9[G]->x=8[G*]) occurring in parallel in closely diverging diploid lineages. Most of the descending dysploidies detected in Brachypodium resulted from nested chromosome fusions, while just a few were caused by telomeric fusions. The different combinations of these 'orphan' and 'extant' dysploid genomes originated diverse phenotypic differences among species and cytotypes.

<footnote n="1">¹Departamento de Ciencias Agrarias y del Medio Natural. Escuela Politécnica Superior de Huesca. Universidad de Zaragoza, Huesca, Spain. ²Grupo de Bioquímica, Biofísica y Biología Computacional (BIFI, UNIZAR), Unidad Asociada al CSIC, Zaragoza, Spain. ³Plant Cytogenetics and Molecular Biology Group, Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland. ⁴Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), Aragón, Spain.</footnote>
<figure><img src="image_559.png" /></figure>

### S.242.4 Phylogenomics and biogeography of Nicotiana section Suaveolentes

Luiz A. Cauz-Santos¹, Rosabelle Samuel¹, Dominik Metschina¹, Maarten J. M. Christenhusz²,³, Ovidiu Paun¹, Mark W. Chase¹,²,³

1 Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria. 2 Royal Botanic Gardens, Kew, Richmond, UK. 3 Department of Environment and Agriculture, Curtin University, Perth, Western Australia, Australia.

For the last six million years, the Australian Eremaean Zone (EZ) has been as dry as today. The flora and fauna of arid regions worldwide, including the EZ, have been hypothesised to have diversified widely before aridification began, in this case 20 Mya, and slowly adapted as aridity developed. Undocumented are more recently arrived plants that developed arid specialisations in situ. Here, we investigate the biogeography and timing of native allotetraploid tobaccos, Nicotiana sect. Suaveolentes, which putatively entered the EZ 5 Mya. The original allotetraploid migrants from South America were adapted to mesic areas of Australia and only recently radiated in the EZ after developing drought adaptations. Based on coalescent and maximum likelihood analyses designed to corroborate timing of the Australian radiation independently, arrival of Nicotiana sect. Suaveolentes occurred approximately 6 Mya, followed by spread via multiple invasions across the EZ from the ecologically highly diverse Pilbara District (Western Australia), which served as a mesic refugium and cradle for adaptations to harsher conditions. These results demonstrate that poorly adapted plant groups can develop novel adaptations that permit them to disperse extensively and rapidly despite the extremes of heat and drought in the EZ.

### S.242.5 Comparative genomics of woody bamboos using a novel *Arundinaria gigantea* genome

Michael R. McKain¹, Fae D. Bramblepelt¹, Roger Cain², and Michael Fedoroff³

1 Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama, USA. 2 Office of Environmental Services and Historic Preservation, United Keetoowah Band of Cherokee Indians, Tahlequah, Oklahoma, USA. 3 Alabama Water Institute, The University of Alabama, Tuscaloosa, Alabama, USA.

Giant rivercane (*Arundinaria gigantea* (Walter) Muhl., Poaceae) is a woody bamboo species native to the eastern United States. Prior to European colonization, large stands of giant river cane—called canebrakes—formed unique ecosystems across the Southeast. However, these ecosystems have undergone significant reduction, diminishing to a mere fraction of their original size. This decline has resulted in the dwindling or extinction of multiple species that depended on canebrakes for survival. Moreover, giant river cane holds considerable significance in the cultural practices of numerous Indigenous Peoples, making it both a cultural and ecological keystone species. As a member of the tribe Arundinarieae, *Arundinaria* shares a polyploidy event with other temperate woody bamboo species and is part of a complex subgenomic history associated with multiple polyploid events and reticulate evolution across the bamboos. In this study, we present the first chromosome-scaffolded genome of *Arundinaria gigantea*. Using this genome and other available bamboo genomes, we characterize variation in how shared and different polyploid events have diploidized in the bamboos. We consider patterns of transposon diversity, retention of paralogs, differences in post-polyploid tandem gene duplications, structural changes, and homoeologous exchange, and examine how they influence overall subgenome contribution to genes associated with potentially adaptive phenotypes. Given the uniquely high discrepancy across bamboos for flowering cycle times, we focus on genes identified through transcriptomes generated from floral and fruit tissue taken at various developmental stages to investigate how these genes have evolved across different bamboo lineages. Finally, we discuss the future of how the *Arundinaria* genome will be used to assess genotypic and phenotypic diversity across populations of giant river cane in efforts to restore these lost ecosystems and promote the protection of threatened species and Indigenous cultural practices.
<figure><img src="image_560.png" /></figure>

## S.242.6 Genomic changes between early generations of allopolyploids show diploidization and increased progeny fitness in Tragopogon

Ingrid E Jordon-Thaden¹,²,³, Douglas E. Soltis³, Pamela S. Soltis²,³

1 Department of Botany, University of Wisconsin Madison, Madison, Wisconsin, USA. 2 Florida Museum of Natural History, University of Florida, Gainesville, Florida, USA. 3 Department of Biology, University of Florida, Gainesville, Florida, USA.

Recently formed allopolyploids *Tragopogon mirus* and *T. miscellus* (Asteraceae) and their diploid parental species, *T. dubius*, *T. porrifolius*, and *T. pratensis*, offer an opportunity to study the earliest stages of allopoly-ploidy. This study is the first large-scale common-gar-den and genotyping experiment to assess genomic and phenotypic trait variation in the North American *Tragopogon* allopolyploid complex from both natural and synthetic lines. We conclude that polyploidization contributes to larger progeny and therefore improved establishment of the young plant, as well as the al-

ready known gigas effect observed in mature poly-ploid plants, resulting in increased competitive ability. Natural populations as well as the three generations of resynthesized allopolyploid lines examined here gener-ally showed minor phenotypic trait differences, indi-cating that any trait differences due to polyploidization were seen in the very first generation after allopolyploi-dy had occurred and did not change much in subse-quent generations after polyploid formation. Likewise, we detected evidence of diploidization via gene loss and as well as gene silencing in the first generations after polyploid formation and repeated across differ-ent lineages. We observed increasing gene loss and silencing over several generations of synthetic poly-ploids and even more in the natural polyploids ap-proximately 45-50 generations old. Both genomic and expression changes are maintained and continue to accumulate over subsequent generations at a steady rate over time, with gene loss occurring at a great-er magnitude and rate than gene silencing over the same time period. Gene silencing does not seem to be a prerequisite for gene loss, and the two processes may operate independently of each other. Our find-ings confirm McClintock's hypothesis of genomic and transcriptomic shock following hybridization, but in this case following allopolyploidization. Together, these re-sults further demonstrate the dynamic nature of poly-ploid genomes shortly after their formation.

## S.243 THE JOURNAL OF PLANT RESEARCH'S SYMPOSIUM ON BIOTIC INTERACTIONS AND BIOLOGICAL INVASION. SESSION 2

### S.243.1 Traits of co-occurring native and non-native plants in invaded communities

Montserrat Vilà¹,², Javier Galán Díaz³, Ingrid M Parker⁴, Enrique G. de la Riva⁵

1 Doñana Biological Station (CSIC), Sevilla, Spain. 2 Department of Plant Biology and Ecology, University of Sevilla, Sevilla, Spain. 3 Department of Pharmacology, Complutense University of Madrid, Madrid, Spain. 4 Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, USA. 5 Department of Biodiversity and Environmental Management, University of León, León, Spain.

Many plant species of European origin have been introduced to North America. Many of these intro-duced species are highly competitive, and have displaced endemic native plant species. However, in most invaded communities, non-native species co-occur with some native species. We investigated the role of non-native plant species in the functional assembly of putative donor and recipient commu-nities by conducting coordinated floristic surveys and analysis of plant traits related to competitive ability in California and Spanish grasslands. While in Spain, all species were native, in California, half spe-cies were non-native. All non-native species found in California grasslands were native in Spain. Many non-native species were more abundant in the Californian invaded grasslands than in the com-