ABSTRACT Recent studies have qualitatively inferred pressure forces within inflorescences and flowers from the deformation patterns observed in floral meristems. Here, we aim to develop a quantitative biophysical model to better characterize these pressures. Our phyllotaxis-based model enables the assignment of numerical values to mechanical forces according to the spatial arrangement of neighboring organs, including bracts, bracteoles, and adjacent floral meristems within inflorescences. We parameterized the model across a range of species representing diverse angiosperm families. These include Portulacineae, whose flowers are laterally compressed by two opposing involucral bracts, and Sapindaceae, in which the genus Acer exhibits remarkable diversity in inflorescence architecture, from simple decussate botryoids to complex abracteolate cincinni. In the Faboideae, Astragalus compactus illustrates how a zygomorphic Bauplan can be mechanically deformed by pressure exerted by a subtending leaf. Overall, the model successfully simulates the mechanical pressures inferred from nearly all developmental biology studies addressing this phenomenon.

ABSTRACT The genus Halerpestes (Ranunculaceae) is a taxonomically small yet geographically widespread lineage that has been often confused with Ranunculus and other Ranunculus-like genera. Halerpestes is native to Eurasia and the Americas, with some species occupying multiple continents and exhibiting diversity in cytotypes across their range. Unlike members of core Ranunuculus, species of Halerpestes have diversified as obligate riparian halophiles. Using ddRADseq, we here advance phylogenetic study to assess the monophyly of Halerpestes, and within the genus, to assess the monophyly of species complexes that are geographically widespread. We generated new chromosome count data for two species and compiled data from previously generated counts to summarize current knowledge of karyotypes in the genus. Our sequence data always reconstructed Halerpestes as monophyletic and distinct from Ranunculus, according to the samples included. Multiple accessions from each of the widespread species were nearly always resolved as monophyletic, indicating that these geographically widespread species are genetically cohesive despite their broad ranges. The evolutionary history of chromosome number in Halerpestes is marked by recurrent polyploidization, both within and across species, both in the New World and in the Old World. Our work constructs a foundation for elucidating a fuller and better understanding of the taxonomic and evolutionary breadth of this morphologically weakly differentiated genus.

ABSTRACT Mangroves play fundamental roles in global wetland ecosystems, providing numerous benefits to society and the environment. This unique species is also utilised for its medicinal properties in traditional and modern medicine due to its remarkable phytochemistry and biological activities. Numerous studies have attempted to record the medicinal applications of mangroves from different perspectives. However, there is currently no review that accounts for the medicinal properties and therapeutic significance of South American mangroves. We conducted a comprehensive review of over 145 relevant scholarly articles found through formal searches of local and global literature and citation databases to examine the distribution and morphological characteristics of South American mangroves. We also compiled their medicinal utilisation and highlighted the existing literature gaps and future research priorities. Our findings identified eleven primary mangrove species that have extensive uses to treat several ailments, including wounds, snakebites, worm infections, asthma, constipation, diabetes, obesity, and Alzheimer’s disease. Secondary metabolites, including flavonoids, tannins, saponins, sterols, and alkaloids, were also identified in these species, which have shown to have anti-inflammatory, anti-ulcer, antioxidant, anthelmintic, anti-diarrhoeal, anti-fertility, anticancer, analgesic, anti-tumour, and antimicrobial properties. While the documentation of the medicinal properties of certain mangrove species is lacking in South America, our findings support their potential applications for future research advancements in the pharmaceutical and cosmetic industries through continued research on their toxicity levels and bioactive mechanisms. Within this contention, our review also underscores the necessity for the conservation and preservation of these forests for their continued benefits to mankind.

ABSTRACT Pollen grains of plant species have unique morphological characteristics. The characteristics, such as variability in pollen shape, size, and microscopic surface features, can be effectively used in the identification of plant species. This approach can be helpful in the identification of medicinal plant species that have a rich biodiversity. This study presents a computer vision-driven framework designed for the segmentation and classification of pollen images acquired through scanning electron microscopy (SEM). This framework has broad applications in palynological fields, including taxonomy, paleoecology, and biodiversity monitoring. While the methodology is universally applicable, we illustrate its effectiveness using a representative dataset consisting of SEM images from 28 medicinal plant species, selected for their morphological diversity and availability. The dataset features 269 images dedicated to segmentation and 5842 images for classification across 28 distinct classes, which have been compiled into an open-access resource titled MPalyn (Medicinal Pollen and Palynology SEM Database). This study demonstrates a broad application in offering a scalable and adaptable tool for automated pollen analysis, which has the potential to advance research in different fields of palynology.

ABSTRACT Amphora copulata is a widely reported diatom name in water quality surveys throughout Europe. Following a survey of 1 000 floristic lists from the French part of the Rhine-Meuse basin (2000–2021), seven samples with the highest abundance of this species were selected for detailed examination-based on light (LM) and scanning electron microscopy (SEM) observations. In addition, samples from the Netherlands and Germany with a high abundance of the Amphora copulata species complex were also studied. The specimens previously identified as A. copulata sensu lato could not be assigned to an existing species based on the currently available literature, and proved to belong to two taxa described here as new: Amphora vanderwerffiana sp. nov. and Amphora lucectoreana sp. nov. The two new species are illustrated using both light and electron microscopy and compared to morphologically similar species. As such, type materials of A. eileencoxiae and A. neglectiformis, and recent material from the type locality of A. macedoniensis are also illustrated and discussed.

ABSTRACT A new fossil diatom species of Encyonema Kützing was collected from the Pleistocene sediments of Colônia basin, State of São Paulo, Southeast Brazil, as part of an ongoing survey of its sedimentary record, aiming at exploring the long-term evolution of the Southern Hemisphere lowland rainforest. Morphology of the new species was examined using both light and scanning electron microscopy, and compared with the morphologically closest species in the genus, Encyonema latum Krammer and E. macedonicum Z.Levkov, D.Metzeltin and S.Krstic. The new species is characterized by a distinctly dorsiventral valve outline, a nearly straight ventral margin, and a relatively low length-to-width ratio, along with a higher areolae number. Preliminary diatom analysis of the Colônia basin sedimentary record indicates that the new species occurred associated with high organic matter input and shallow lake conditions, during a cold and humid period. The study contributes to the understanding of the Colônia basin biodiversity and will assist future ecological and evolutionary studies in the region.

ABSTRACT A new species, Anisotaenia centrozagrica (Apiaceae), is described from a small area in the Central Zagros Mountains of western Iran. Found on rocky slopes near the Absefid waterfall in Lorestan Province, the species shows a unique combination of morphological traits, such as long, uniform terminal leaf lobes and narrow-winged mericarps that clearly set it apart from other members of the genus. Molecular analyses based on ITS and rps16 sequences support its placement as an independent lineage within Anisotaenia, closely related but separate from A. subvelutina. The new species is currently only known from a single locality representing a specific microhabitat, where it is under pressure from overgrazing and tourism-related disturbance, in addition to climate-related shifts in snow and rainfall patterns. These conditions, combined with its very narrow distribution, suggest that the species should be considered Critically Endangered under IUCN criteria. This finding adds to our understanding of species diversity in the genus and highlights the ecological importance of habitat diversity in the central Zagros region.

ABSTRACT Dryopteris minor is described and illustrated as a new diploid sexual species of Dryopteridaceae from southern Yunnan, at the border between China and Vietnam, based on morphological and molecular analyses. This new species is morphologically characterized by its twisted brown scales, bipinnate fronds, ovate-lanceolate lamina, and serrate pinnule apices. Phylogenetic analyses of plastome and nuclear gene sequences revealed that D. minor is closely related to D. integriloba, D. jiulungshanensis, and D. yenpingensis. A detailed morphological description is provided for the new species. The conservation status is evaluated as critically endangered.

ABSTRACT Carnivorous plants such as Nepenthes secrete acid phosphatase (ACP) into their digestive fluids, probably to facilitate the scavenging of inorganic phosphate (Pi) from prey-derived organic phosphate (Po) sources, thereby promoting plant growth. To investigate whether the ACP-containing digestive fluid promotes Pi acquisition, 7-day-old Arabidopsis seedlings were grown in liquid half-strength Murashige and Skoog (MS) medium supplemented with the digestive fluid obtained from the unopened pitchers of N. khasiana, which had been incubated with DNA, a likely Po source from digested prey. This fluid exhibited significantly higher ACP activity that remained unaffected despite increased phosphate levels in the growing medium than the fluid from opened pitchers and contained an ACP protein similar to those reported in other Nepenthes species. Surprisingly, the ACP-containing digestive fluid significantly inhibited Arabidopsis plant growth. Even after heat deactivation, the digestive fluid failed to stimulate growth and instead severely repressed it. Similar inhibitory effects were observed with the digestive fluid obtained from the opened pitchers of N. khasiana. To further explore this finding, Arabidopsis seedlings were treated with varying concentrations of two heat-stable 1,4-naphthoquinones, droserone (0–250 µM) and plumbagin (0–400 µM), including the non-radical reactive oxygen species H2O2 (0–2 µM), all of which have been reported in the digestive fluids of Nepenthes pitchers. While H₂O₂ had no significant effect on plant growth, droserone caused significant growth inhibition at 250 µM concentration, and plumbagin inhibited growth at concentrations as low as 25 µM. These findings suggest that naphthoquinones may be responsible for the observed growth inhibition.

ABSTRACT As a part of the ongoing taxonomic revision of the Indian Oleaceae, the need of typification of a few names published by Wilhelm Sulpiz Kurz was identified. Lectotypes for the names Myxopyrum smilacifolium (Wall.) Blume var. illicifolium and Schrebera pubescens, have thus been designated in accordance with the Madrid Code.