Search

Premise: Increases in genome size in plants—often associated with larger, low‐density stomata and greater water‐use efficiency (WUE)—could affect plant ecophysiological and hydraulic function. Variation in plant genome size is often due to polyploidy, having occurred repeatedly in the austral sedge genus Schoenus in the Cape Floristic Region (CFR), while species in the other major schoenoid genus in the region, Tetraria, have smaller genomes. Comparing these genera is useful as they co‐occur at the landscape level, under broadly similar bioclimatic conditions. We hypothesized that CFR Schoenus have greater WUE, with lower maximum stomatal conductance (gwmax) imposed by larger, less‐dense stomata. Methods: We investigated relationships between genome size and stomatal parameters in a phylogenetic context, reconstructing a phylogeny of CFR‐occurring Schoeneae (Cyperaceae). Species' stomatal and functional traits were measured from field‐collected and herbarium specimens. Carbon stable isotopes were used as an index of WUE. Genome size was derived from flow‐cytometric measurements of leafy shoots. Results: Evolutionary regressions demonstrated that stomatal size and density covary with genome size, positively and negatively, respectively, with genome size explaining 72–75% of the variation in stomatal size. Larger‐genomed species had lower gwmax and C:N ratios, particularly in culms. Conclusions: We interpret differences in vegetative physiology between the genera as evidence of more‐conservative strategies in CFR Schoenus compared to the more‐acquisitive Tetraria. Because Schoenus have smaller, reduced leaves, they likely rely more on culm photosynthesis than Tetraria. Across the CFR Schoeneae, ecophysiology correlates with genome size, but confounding sources of trait variation limit inferences about causal relationships between traits. [ABSTRACT FROM AUTHOR]

The fundamental value of universal nomenclatural systems in biology is that they enable unambiguous scientific communication. However, the stability of these systems is threatened by recent discussions asking for a fairer nomenclature, raising the possibility of bulk revision processes for "inappropriate" names. It is evident that such proposals come from very deep feelings, but we show how they can irreparably damage the foundation of biological communication and, in turn, the sciences that depend on it. There are four essential consequences of objective codes of nomenclature: universality, stability, neutrality, and transculturality. These codes provide fair and impartial guides to the principles governing biological nomenclature and allow unambiguous universal communication in biology. Accordingly, no subjective proposals should be allowed to undermine them. [ABSTRACT FROM AUTHOR]

This article provides an overview of the biodiversity and evolution of African flora. Africa is home to a diverse range of ecosystems and has a rich variety of vascular plants, with over 65,000 recorded species. However, the cataloging of African plant diversity is uneven, with some regions well-documented and others barely explored. The article also explores the biogeographic history of African plants, the role of fire in shaping the flora, and the impact of climate change on plant diversity. The authors emphasize the need for conservation efforts specific to Africa, as the processes that have shaped its flora differ from those in other parts of the world. They also highlight the gaps in our understanding of African plant diversity and call for further research and data collection. [Extracted from the article]

Background and Aims The quartz fields of the Greater Cape Floristic Region (GCFR) are arid and island-like special habitats, hosting ~142 habitat-specialized plant species, of which 81 % are local endemics, characterized by a rapid turnover of species between and among sites. We use several phylogenetic community metrics: (1) to examine species diversity and phylogenetic structure within and among quartz fields; (2) to investigate whether quartz field specialists are evolutionarily drawn from local species pools, whereas the alternative hypothesis posits that there is no significant evolutionary connection between quartz field specialists and the local species pools; and (3) to determine whether there is an association between certain traits and the presence of species in quartz fields. Methods We sampled and developed dated phylogenies for six species-rich angiosperm families (Aizoaceae, Asteraceae, Crassulaceae, Cyperaceae, Fabaceae and Santalaceae) represented in the quartz field floras of southern Africa. Specifically, we focused on the flora of three quartz field regions in South Africa (Knersvlakte, Little Karoo and Overberg) and their surrounding species pools to address our research questions by scoring traits associated with harsh environments. Key Results We found that the Overberg and Little Karoo had the highest level of species overlap for families Aizoaceae and Fabaceae, whereas the Knersvlakte and the Overberg had the highest species overlap for families Asteraceae, Crassulaceae and Santalaceae. Although our phylogenetic community structure and trait analyses showed no clear patterns, relatively low pairwise phylogenetic distances between specialists and their local species pools for Aizoaceae suggest that quartz species could be drawn evolutionarily from their surrounding areas. We also found that families Aizoaceae and Crassulaceae in Knersvlakte and Little Karoo were phylogenetically even. Conclusions Despite their proximity to one another within the GCFR, the studied areas differ in their species pools and the phylogenetic structure of their specialists. Our work provides further justification for increased conservation focus on these unique habitats under future scenarios of global change. [ABSTRACT FROM AUTHOR]

Background and Aims The Greater Cape Floristic Region is one of the world's biodiversity hotspots and is considered poor in polyploids. To test this assumption, ploidy variation was investigated in a widespread Cape shrub, Dicerothamnus rhinocerotis (renosterbos, Asteraceae). The aim was to elucidate the cytotype distribution and population composition across the species range, and to assess differences in morphology, environmental niches and genetics. Methods Ploidy level and genome size were determined via flow cytometry and cytotype assignment was confirmed by chromosome counting. Restriction site-associated DNA sequencing (RADseq) analyses were used to infer genetic relationships. Cytotype climatic and environmental niches were compared using a range of environmental layers and a soil model, while morphological differences were examined using multivariate methods. Key Results The survey of 171 populations and 2370 individuals showed that the species comprises diploid and tetraploid cytotypes, no intermediates and only 16.8 % of mixed populations. Mean 2C values were 1.80–2.06 pg for diploids and 3.48–3.80 pg for tetraploids, with very similar monoploid genome sizes. Intra-cytotype variation showed a significant positive correlation with altitude and longitude in both cytotypes and with latitude in diploids. Although niches of both cytotypes were highly equivalent and similar, their optima and breadth were shifted due to differences mainly in isothermality and available water capacity. Morphometric analyses showed significant differences in the leaves and corolla traits, the number of florets per capitulum, and cypsela dimensions between the two cytotypes. Genetic analyses revealed four groups, three of them including both cytotypes. Conclusions Dicerothamnus rhinocerotis includes two distinct cytotypes that are genetically similar. While tetraploids arise several times independently within different genetic groups, morphological and ecological differences are evident between cytotypes. Our results open up new avenues for questions regarding the importance of ploidy in the megadiverse Cape flora, and exemplify the need for population-based studies focused on ploidy variation. [ABSTRACT FROM AUTHOR]

The Committee on Institutional Votes was established at the XIX International Botanical Congress (IBC), in Shenzhen in 2017, with the mandate to maintain a list of institutions and their allocated votes for the upcoming IBC, the next of which will be the XX IBC in Madrid in July 2024. Institutions worldwide were informed of the mechanism to apply for one or more institutional votes or to request a change in previously allocated votes. Forty applications were received by the Committee, of which 28 were from institutions new to the list, 9 requested an increase in allocated votes and 3 requested no change to allocated votes. All requests were accepted, two of them partly so. Adjustments were also made for two institutions that had been closed or transferred. The Committee sent a draft of this report together with the revised list for Madrid to the General Committee for final approval, as required by the International Code of Nomenclature for algae, fungi, and plants. The General Committee approved the list, which is now presented here. The total number of institutions on the list is 572; the total number of institutional votes that could potentially be exercised is 970. Only 30.4% of institutions exercised their votes in Shenzhen in 2017. Institutions are urged to exercise their votes in Madrid in 2024, and instructions for this are provided. [ABSTRACT FROM AUTHOR]