This study aimed at exploring the usefulness of pollen in the taxonomy of brambles (Rubus subgen. Rubus), focusing on the diversity of palynological traits among diploids, polyploids, hybrids, and horticultural cultivars. Using light microscopy and scanning electron microscopy, we examined 62 samples representing six diploid species, 16 polyploid taxa, nine hybrids, and three cultivars from various geographic regions. Quantitative traits—polar axis length (P), equatorial diameter (E), P/E ratio, ectocolpi length (Lc), and exine thickness along the polar axis (Exp)—were measured and statistically analysed to evaluate intraspecific and interspecific variation and to explore correlations with ploidy levels. Our results revealed significant morphological differences within and among the four studied groups. Diploid species exhibited smaller pollen grains and greater intra- and interspecific variability than polyploids, supporting the hypothesis that pollen size correlates with ploidy level. Pollen shape was predominantly subprolate and prolate, but shape alone proved unreliable for species discrimination. Exine ornamentation was largely homogeneous across taxa, characterised by striate-perforate patterns, which limited its diagnostic value. Pollen size traits showed positive significant correlations with ploidy levels. Contrast analyses between parental species and hybrids indicated that hybridisation influences pollen morphology, with some hybrids displaying intermediate or distinctive characteristics. In addition, reproductive mode (sexual vs. apomictic) did not significantly affect pollen traits at the same ploidy level. Overall, pollen morphology, particularly size-related traits, can be used as supplementary traits in Rubus taxonomy, e.g. in ploidy determination. However, they must be combined with additional data for reliable species distinction.
Cytogenetic data remain limited for many lineages of Cactaceae, constraining our understanding of chromosome evolution in this diverse family. Here, we combine newly generated cytogenetic and genome size data for Armatocereus mataranus subsp. ancashensis with a comparative dataset of ribosomal DNA (rDNA) organization across Cactaceae to examine patterns of locus number and chromosomal distribution. rDNA loci were analysed using fluorescence in situ hybridization (FISH) with 5S and 45S probes, and nuclear DNA content was estimated by flow cytometry. Somatic cells exhibited 2n = 22 chromosomes, consistent with a diploid condition based on x = 11. Two 5S rDNA loci were located on different chromosome pairs, while a single terminal 45S rDNA locus was detected on another pair. The diploid genome size was estimated at 2C = 2.73 pg, and flow cytometric profiles indicated the presence of endopolyploidy. Comparative analyses across Cactaceae show that rDNA locus number and chromosomal distribution in A. mataranus subsp. ancashensis are broadly consistent with patterns reported in both Cactoideae and Opuntioideae. These findings place the cytogenetic characteristics of this taxon within a broader comparative context and highlight patterns of both conservation and variation in rDNA organization across Cactaceae. Finally, these data may be useful as a cytogenetic reference for future conservation studies on A. mataranus subsp. ancashensis.
Jatropha excisa is found throughout the Chaco phytogeographical province in Argentina, Bolivia, and Paraguay, but its taxonomic boundaries are unclear. This study investigates whether J. excisa comprises more than one species, examining genetic variation and morphological traits, its genetic diversification over time, its native or introduced status in the Chaco, and its distinctiveness from J. gossypiifolia. We analyzed nuclear (ITS) and chloroplast (trnL-trnF) genes from 52 individuals across 32 locations. The results revealed 12 nuclear alleles grouped into four clusters and 29 chloroplast haplotypes with no clear geographic structure. Phylogenetic analysis identified four major clades diverging between 1.8 and 8.1 million years ago, with one clade corresponding to J. excisa and another to J. thyrsantha, indicating at least two distinct species. The findings suggest an ancient divergence among allele groups and a slow geographic expansion of J. excisa over the last 150,000 years. This research supports recognizing J. excisa as a distinct native species in the Chaco, diverging from J. gossypiifolia around 18 million years ago, and emphasizes the need for further studies on hybridization and genetic flow among Jatropha species for conservation efforts.
Species delimitation based only on morphological characters can be challenging in groups where morphology is highly variable or difficult to study. In such cases, molecular data may be used to test the robustness of morphology-based taxonomic treatments. In Cyperaceae, phylogenomic studies have helped clarify relationships and taxon delimitation at the genus level and above, but species delimitations and relationships remain poorly documented in many genera, notably Bulbostylis (hairsedges). Bulbostylis is a morphologically diverse and taxonomically complex group, with Madagascar representing one of its centres of endemism. Species delimitation within the genus has long been hindered by the scarcity of stable diagnostic characters and the absence of molecular data. To evaluate whether the Malagasy Bulbostylis species correspond to distinct evolutionary lineages, we sequenced 353 nuclear loci (Angiosperms353) from 102 specimens collected between 1805 and 2023, including herbarium and silica-dried material. After removing samples with low sequencing success, 64 accessions representing 25 species were retained. Target sequence capture data were analysed using standard phylogenomic approaches, including sequence alignment, maximum likelihood gene tree inference, and species tree inferences using maximum likelihood and multispecies coalescent summary approaches. Phylogenetic analyses recovered 13 well-supported clades corresponding to taxa currently recognised based on morphological characters (B. andringitrensis, B. barbata, B. erectopallescens, B. festucoides subsp. bathiei, B. filamentosa, B. firingalavensis, B. hispidula, B. mahafalensis, B. micranthera, B. renschii, B. schoenoides, B. tristicha, B. viguieri), and highlighted a possible case of budding speciation with B. trichobasis being nested inside B. andringitrensis in the species trees. Potentially undescribed taxa closely related to B. flaccidula and B. pseudocollina were identified, while another ten species will require further investigation due to low or no data availability. Additional field collection of fresh material, together with sequencing and analysis of other herbarium specimens, will be necessary to fully understand species delimitations in these lineages. These results indirectly show that morphological characters such as inflorescence architecture, glume morphology, leaf sheath, and nutlet features remain highly reliable for species identification in Malagasy Bulbostylis.
We describe Oplonia doceana sp. nov. (Acanthaceae), a new species endemic to the campos rupestres of the João Pinto Formation in the Doce River basin, within the Atlantic Forest domain of southeastern Brazil. This is the first confirmed record of Oplonia in Brazil, extending the genus beyond its previously known range in Argentina, Bolivia, Peru, the West Indies, and Madagascar. Phylogenetic analysis based on plastid and nuclear regions supports its placement within Oplonia, where it is recovered as sister to O. jujuyensis, native to Argentina and Bolivia. Morphologically, the species differs by its erect habit, chartaceous leaves with domatia, red infundibular corolla, and unusual terminal inflorescences, which contrast with the axillary inflorescences typical of Oplonia. These traits suggest a potential pollination shift and highlight challenges in Graptophyllinae taxonomy, where generic boundaries remain unclear. Oplonia doceana is currently known from only a few locations and specialized habitats facing multiple threats, including fire, invasive species, and ongoing habitat disturbance, qualifying it as Endangered under IUCN criteria. This discovery adds to a growing list of narrowly endemic angiosperms in the region and emphasizes the João Pinto Formation as a hotspot of botanical novelty and conservation priority within the Atlantic Forest domain, underscoring the urgent need for continued taxonomic research and targeted conservation in the Doce River basin.
Climax vegetation in the Japanese Archipelago is dominated by forest, yet grassland patches persist semi-naturally. Over the past century, grassland coverage has declined from approximately 14
Ginkgo biloba is a relict species of major phylogenetic and conservation significance. Previous studies have largely clarified the major lineage structure of G. biloba based on molecular evidence, particularly chloroplast genome data. However, recent field investigations identified a Ginkgo biloba population at Guniujiang, Anhui, and comprehensive observations suggested that this population has considerable research potential. In this study, six G. biloba samples from Guniujiang, Qingliangfeng, and Tianmu Mountain were analyzed using complete chloroplast genome assembly, comparative genomics, and phylogenetic reconstruction. All six chloroplast genomes exhibited the typical quadripartite circular structure and ranged from 156,938 to 157,009 bp in length, with GC contents of 39.56–39.57
The behaviour of B chromosomes—supernumerary chromosomes found across diverse organisms—during meiosis and genetic effects in lilies is poorly understood. Here, we systematically investigated the behaviour of the B chromosome of triploid lily ‘Orange Emperor’ during meiosis via conventional cytological techniques, focusing on its dynamics across meiotic stages, its influence on genetic diversity, and interactions with A chromosomes. Furthermore, we used ‘Orange Emperor’ as a maternal parent in hybridisation with Asiatic lilies to analyse progeny genetic characteristics. The results indicate that the B chromosome in ‘Orange Emperor’ remains univalent and does not associate with any A chromosome during meiosis. Separation primarily occurs at anaphase I, followed by random distribution in the resulting microspores. A cross between ‘Orange Emperor’ (female parent) and a diploid Asiatic lily yielded few offspring. All hybrid progeny were aneuploids with variable number of A chromosome (ranging from 25 to 31) and, in some cases, contained at most one B chromosome as a supernumerary element. We found unique meiotic behaviour and inheritance patterns of B chromosomes. The B chromosome exhibited lack of pairing and precocious separation in male meiosis, followed by random distribution in microspores. When transmitted through female lineage, a single B chromosome copy was inherited by 50
This study examines the genetic and morphological variability within the Quercus pubescens s.l. complex of Sardinian white oak populations, including Q. congesta, Q. ichnusae, and Q. virgiliana. These tree taxa act as umbrella species in several climax communities across the Sardinia Island. A comparison of actual and potential cover of the different types of Sardinian deciduous oak forests was carried out. Ten EST-SSR markers were analysed to examine genetic diversity and differentiation within and among populations. Genetic structure was assessed using Bayesian clustering methods while relationships between populations were assessed by means of multivariate analyses. Five additional Q. pubescens populations from Italy, Spain, and Croatia and three populations belonging to Q. frainetto, Q. petraea, and Q. robur from peninsular Italy were also included in the genetic analyses. The morphometric analysis was performed on twelve leaf morphological traits focussing exclusively on the Sardinian populations. The results showed that deciduous oak forests occupy only a fraction of their potential area. Xero-thermic pubescent oak forests showed the greatest loss of their potential coverage. Neither genetic nor morphometric data revealed sufficient levels of diversity between populations to justify the current taxonomic classification of Sardinian pubescent oaks into four different taxa. Minimal genetic differentiation was found within the entire group of Q. pubescens s.l., whereas a clear separation among Q. frainetto, Q. petraea, Q. pubescens, and Q. robur was highlighted. Nevertheless, two major gene pools were identified within the Q. pubescens s.l. group with geographic distance among populations having a predominant influence over taxonomic boundaries.
Plant mitochondrial genomes (mitogenomes) exhibit complex and dynamic architectures. However, their physical structures remain unevenly resolved in many gymnosperm lineages. In Pinaceae, the limited number of structurally validated mitogenomes constrains comparative analyses of mitogenome architecture and the development of mitochondrial resources for studies of maternal lineage history and seed-mediated dispersal. To help address this gap, we assembled and structurally characterized the mitochondrial genome of Sakhalin fir (Abies sachalinensis) using PacBio high-fidelity (HiFi) long reads and validated contig connections using polymerase chain reaction to support the inferred genome conformation. The mitogenome comprises of 12 contigs with a length of 942.73 kbp containing 41 protein-coding genes, 3 rRNA genes, and 11 tRNA genes. Structural analysis revealed a large multi-branched genomic component together with a small circular molecule. Repeat analysis identified 479 simple sequence repeats and 678 dispersed repeats across 12 mitogenomic contigs. We identified mitochondrial plastid DNAs in the mitogenome and chloroplast genome of A. sachalinensis, as well as 1,488 potential C-to-U RNA editing sites supported by prediction and RNA-seq evidence. Phylogenetic analysis based on 26 shared mitochondrial protein-coding genes reconstructed relationships consistent with the current classifications of Pinaceae and confirmed the placement of A. sachalinensis within the genus Abies. Comparison with previously published Pinaceae mitogenomes suggested that this complex structure may exhibit a common structural pattern within the family. This structurally supported mitogenome provides a resource to support future investigations on mitochondrial genome evolution, maternal lineage structure, seed-mediated processes, and systematics in the genus Abies and across Pinaceae.
During revisional works and based on newly collected specimens, new data are provided on the diversity, distribution and phylogeny of three species of subtribe Lactucinae in Iran. The annual Lactuca austroiranica is described from southern Iran as new to science. It is endemic to the Irano-Turanian region and grows in the Juniperus-Pistacia woodlands. Morphologically it is most similar to L. dissecta and L. dolichophylla and molecular phylogenetic analysis of nrDNA ITS sequences support its position as sister to the two species. Lactuca leucoclada, previously known only from Afghanistan and Türkiye, is newly recorded for Iran. The recently described L. birjandica is demonstrated to be conspecific with the regional endemic and phylogenetically isolated L. picridiformis. Own collections of this species helped to improve the knowledge of its distribution in eastern Iran. A second step lectotype is designated for the name L. picridiformis. Photographs of living plants and a distribution map of the studied species in Iran are presented. An updated inventory of the Lactucinae in Iran, including 35 taxa (31 species belonging to Lactuca and 4 to Cicerbita), is provided.
Polyploidy is a common mechanism of speciation in flowering plants, but its influence on morphology and ecology is often uncertain. Allopolyploidy in the genus Clarkia has led to several widespread species that overlap geographically and morphologically with diploid progenitors, causing taxonomic challenges. One example is C. rhomboidea, an allopolyploid that frequently co-occurs with its diploid progenitor, C. virgata, a narrow endemic. Using flow cytometry and a greenhouse common garden, we evaluated the ploidy of new and existing records and identified floral traits that can distinguish the species. We then used two diagnostic floral traits to determine the frequency of misclassifications in occurrence databases. We also conducted studies of phenology in the field. Last, we asked whether the geographic range and niche (breadth and overlap) were influenced by misclassifications. Where their ranges overlap, we found that 45
Pinguicula (Lentibulariaceae, Lamiales) is a monophyletic genus consisting of ca. 80–100 carnivorous species distributed across subarctic, temperate, and tropical regions. To date, phylogenetic relationships within the genus remain insufficiently resolved, and with the exception of P. balcanica, no samples from Türkiye have been included in such studies. Moreover, Türkiye’s role in the evolutionary history of the genus has been entirely overlooked. Neither the recently described P. habilii, endemic to Muğla in southwestern Anatolia, nor other taxonomically problematic taxa (i.e., P. crystallina, P. megaspilaea, and P. hirtiflora) from Anatolia, Cyprus, and Greece have been comprehensively included in phylogenetic studies. Although these taxa have occasionally appeared in earlier works, they have never been analyzed within a focused and integrative phylogenetic framework. Furthermore, key questions regarding the timing and geographic origin of the Türkiye and Cypriot lineages, the historical dispersal routes leading to their present-day distributions, and the historical biogeographic processes that have shaped these patterns have remained unexplored. To address these gaps and to establish a comprehensive phylogenetic framework for the genus, we conducted a molecular phylogenetic study of Pinguicula. This study incorporated newly generated DNA sequences together with publicly available sequences retrieved from GenBank, including nuclear DNA (ITS region) and plastid DNA regions (trnH-psbA and rpL32-trnL). Our Maximum Likelihood (ML) and Bayesian Inference (BI) analyses revealed that, although the genus is monophyletic, the Pinguicula crystallina/hirtiflora complex is still undergoing speciation, likely due to its relatively recent origin. Within this complex, only P. megaspilaea was recovered as strongly monophyletic, whereas its phylogenetic placement differed substantially between the nuclear and plastid datasets. Similarly, P. balcanica was recovered as two well-supported clades in the nuclear phylogeny, but as a single clade in the rpL32-trnL plastid phylogeny, representing an additional case of cytonuclear discordance within the genus. Taken together, these results indicate a complex and dynamic evolutionary history within Pinguicula, in which reticulate evolution and geographic isolation appear to have played significant roles. On the other hand, our molecular dating and ancestral biogeographic analyses indicated that the genus Pinguicula most likely originated in Europe approximately 24.69 million years ago, that the Pinguicula crystallina/hirtiflora complex evolved in Greece around 6.46 million years ago, subsequently expanded into Anatolia, and later dispersed from Anatolia to Cyprus.
Silene (Caryophyllaceae) is one of the most diversified genera in North Africa with approximately 144 species recognized by the current taxonomy, of which around one third are endemic to the region. We inferred gene trees from DNA sequences from the nuclear ITS region and the plastid rps16 intron, and a species tree was constructed under the multi-species coalescent (MSC) model. We generated 130 new ITS and 70 rps16 sequences covering the diversity of North African Silene and combined these with those available for Silene on GenBank. We found good agreement with the recently presented phylogeny-aware infrageneric taxonomy of Silene. Most North African taxa belong to a broadly circumscribed S. sect. Silene clade. We complemented the sections Siphonomorpha, Muscipula, Behenantha with 11 North African taxa previously not sequenced. The recently suggested phylogenetic circumscription of sect. Silene was corroborated, including North African representatives previously assigned to sections Atocion, Dipterospermae, Fruticulosae, Nicaeenses, Scorpioides, Silene, and Succulentae. None of these, as circumscribed in North African taxonomic literature, are supported as monophyletic at the subsectional level. Silene nocturna forms two separate clades, which are difficult to distinguish morphologically and require further study of the infraspecific names and heterotypic synonyms. A similar case is observed in S. pomelii, from which S. tagadirtensis should be recognized.
Camellia sect. Tuberculata, characterized by tuberculate ovaries and a primary distribution in Guizhou Province, China, exhibits poorly resolved interspecific relationships due to limited field and experimental data. A prominent case is C. rubimuricata, which has historically been treated as a forma of C. ilicifolia—a taxonomic placement that has remained controversial. To clarify its status, we conducted extensive field surveys at the type locality of C. rubimuricata and carried out integrated morphological, palynological, and molecular phylogenetic analyses (using complete cpDNA and ITS sequences). Comparative morphology revealed clear distinctions between the two species in terms of floral structure, petals, sepals, and fruit. Pollen micromorphology further differentiated two species on the basis of the pollen shape, polar/equatorial ratio (P/E), germination pore structure, and exine ornamentation. Phylogenetic reconstructions from both the cpDNA and ITS datasets consistently placed C. rubimuricata and C. ilicifolia in distinct, strongly supported clades. Therefore, these multidisciplinary lines of evidence strongly support the recognition of C. rubimuricata as an independent species that is distinct from C. ilicifolia. Additionally, this study provides the first comprehensive documentation of several key morphological traits of C. rubimuricata.
Osmiopsis (Asteraceae, Eupatorieae) is endemic to Hispaniola and one of the seven genera of subtribe Praxelinae. When Osmiopsis was established in 1975, the authors hypothesized it was a hybrid and proposed Chromolaena (subtribe Praxelinae) and Koanophyllon (subtribe Critoniinae) as putative parent genera. To clarify its origin, a phylogenetic investigation of subtribe Praxelinae, reconstructed within a matrix of 80 genera/202 species of tribe Eupatorieae (43
Multiple accessions of the simple thalloid liverwort Aneura from around the world, but with particular focus on western Europe, have been sequenced for a range of standard plastid DNA barcoding markers: rbcL, matK, psbA-trnH, rpoC1 and trnL-trnF, and the nuclear ITS marker. Our data set on the Barcode of Life Database (BOLD) currently contains some DNA barcode data for 433 accessions of Aneura. Data for an additional 386 Aneura accessions are available from GenBank or from BOLD. Using tree-building methods, we consider that at least twelve well-sampled and supported lineages within Europe and Greenland merit recognition at the species level. Studies of the ecology and morphology of these lineages have revealed some morphological characters that match the genetic lineages. In this paper, we describe ten new species of Aneura, based on a combination of molecular and morphological data.
Fine-grained image classification remains a challenging problem in computer vision due to high inter-class visual similarity and pronounced intra-class variability. In this study, a systematic and architecture-centric comparison of convolutional neural networks (CNNs), Vision Transformer (ViT) models, and hybrid architectures is presented using the Oxford 102 Flowers dataset, which comprises 8189 images across 102 visually similar categories. Rather than proposing a new architecture or training strategy, this work focuses on a controlled and comparative analysis of widely adopted deep learning paradigms under a unified experimental framework. All models are evaluated under a strictly controlled experimental protocol with fixed data splits, identical preprocessing, and unified optimization settings to reduce experimental confounding factors and enable architecture-level analysis. The experimental results show that large-scale Vision Transformers achieve the highest absolute classification performance within this benchmark setting, with ViT-L/16 attaining an accuracy of 99.37
The genus Saxifraga comprises ca. 480 species and is a characteristic element of mountainous and boreal to subpolar vegetation, particularly in the Northern Hemisphere. It comprises primarily perennial herbaceous plants that often form leaf rosettes and frequently have colorful, insect-pollinated flowers. This study used flow cytometry to estimate the genome sizes of saxifrage species on a broader taxonomic scale, identifying the total range of variation within the genus and its many infrageneric phylogenetic lineages. Measurements were made for 122 species, representing most of the infrageneric groups. Holoploid genome sizes (2C values) exhibited approximately 17-fold variation, whereas monoploid genome sizes (1Cx values) varied slightly less. The highest values were found in the predominantly Himalayan-Tibetan section Ciliatae, while the smallest were in the southern European subsection Arachnoideae. The genome size data were analyzed alongside karyological information, including chromosome numbers, polyploidy, changes in the chromosome base numbers (x = 8–14) and aneuploidy. The potential evolutionary patterns of chromosome and genome differentiation among the main lineages of Saxifraga were analyzed, and possible relationships of genome size with life form, morphology, habitat, ecology, and biogeography were outlined. Additional data were presented for five other Saxifragaceae genera. All the data were used together to evaluate the potential evolution of chromosome base number in Saxifraga and the entire family Saxifragaceae. Additionally, an updated infrageneric classification of Saxifraga was introduced, including the newly designated subsection Irriguae.
Impatiens shanglinensis sp. nov. and I. guangnanensis sp. nov., two new species from southern China, are described and illustrated. I. shanglinensis is morphologically similar to I. guihouensis, but differs significantly in its obovate or obovate-lanceolate lamina, longer bract, narrowly oblong inner lateral sepals and ovate-lanceolate basal lobes. I. guangnanensis is morphologically similar to I. clavigera var. auriculata, but differs significantly in its wingless stem, obovate or obovate-lanceolate lamina, longer pedicel, shorter pedicels and lateral sepals, dorsal petal with retuse apex, triangular-ovate basal lobes and subtetragonous distal lobes. Micromorphological characteristics of pollens and seeds of two new species were observed and molecular data confirms that two new species belong to I. subg. Clavicarpa.
