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BACKGROUND AND AIMS: The Labrador Teas (genus Rhododendron, subsection Ledum) are a complex of species widely distributed in the Northern Hemisphere. They occupy cold-resistant plant communities from highlands to forest understory and wetland habitats almost circumboreally and they are especially abundant in Northeast Asia (NE Asia) and northern North America (NN Am), still there are no clear species boundaries in this group. The genetic structure of species of the subsect. Ledum from Eurasia and North America as well as the dispersal history of the group require clarification. METHODS: Phylogeny and biogeography of the subsect. Ledum of the genus Rhododendron were assessed using phylogenetic trees constructed based on the analysis of variation in chloroplast petB-petD, trnV-ndhC, trnH-psbA, K2R-K707, atpB oligo2 - rbcL oligo5 and nuclear (ITS1) markers of four Eurasian and one American species (65 populations, 408 individuals). The data were evaluated with Maximum Parsimony and Bayesian analysis. Molecular dating and ancestral areas reconstruction were obtained. KEY RESULTS: Dense sampling revealed widespread presence of shared haplotypes and ribotypes among Ledum populations and species. Two American, three Eurasian and one mixed lineage diversified during the Neogene climate cooling and then rapidly dispersed during the Pleistocene. The ability to accumulate high genetic diversity and to preserve it across distribution ranges and generations prevented Ledum from lineage sorting. As a result, a species complex with a reserve of genetic variability appeared. CONCLUSIONS: Although no clear phylogenetic inference can be obtained at present, the plastid genealogy is consisted with the nuclear genealogy and demonstrates the processes involved in speciation in the Ledum species complex.

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The genus Hedysarum L. (Fabaceae) includes about 200 species of annual and perennial herbs distributed in Asia, Europe, North Africa, and North America. Many species of this genus are valuable medicinal, melliferous, and forage resources. In this review, we consider the taxonomic history of the genus Hedysarum, the chromosomal organization of the species from the sections Hedysarum and Multicaulia, as well as phylogenetic relationships between these sections. According to morphological, genetic, and phylogenetic data, the genus Hedysarum is divided into three main sections: Hedysarum (= syn. Gamotion), Multicaulia, and Stracheya. In species of this genus, two basic chromosome numbers, x = 7 (section Hedysarum) and x = 8 (sections Multicaulia and Stracheya), were determined. The systematic positions of some species within the sections are still uncertain due to their morphological similarities. The patterns of distribution of molecular chromosomal markers (45S rDNA, 5S rDNA, and different satellite DNAs) in karyotypes of various Hedysarum species made it possible to determine their ploidy status and also specify genomic relationships within the sections Hedysarum and Multicaulia. Recent molecular phylogenetic studies clarified significantly the taxonomy and evolutionary development of the genus Hedysarum.

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The tree fern Culcita macrocarpa, a threatened Iberian-Macaronesian endemism, represents the sole European species of the order Cyatheales. Considered a Tertiary relict of European Palaeotropical flora, its evolutionary history and genetic diversity, potentially influenced by presumed high clonal propagation, remain largely unknown. This study elucidates the phylogeographic history of C. macrocarpa, assessing the impact of vegetative reproduction on population dynamics and genetic variability. We provide genetic data from eight newly identified nuclear microsatellite loci and one plastid DNA region for 17 populations spanning the species' range, together with species distribution modeling data. Microsatellites reveal pervasive clonality in C. macrocarpa, which has varied among populations. We assess the impact of clonality on genetic diversity and evaluate how estimates of intra-population genetic diversity indices and genetic structuring are affected by the chosen definition of "individual" (focusing exclusively on genetically distinct individuals, genets, as opposed to considering all independent clonal replicates, ramets). We identify two main population groups, one in the northern Iberian Peninsula and the other in the Macaronesian archipelagos and southern Iberian Peninsula. Within each group, we found relict populations (in the Azores and the Cantabrian Cornice) as well as recent originated populations. This population structure suggests colonization dynamics in which recent populations originated from one or a few genets of relict populations and became established through intra-gametophytic self-fertilization and vegetative expansion. DAPC analysis facilitated the identification of alleles that most significantly contributed to the observed population structure. The current Andalusian populations appear to have originated from colonization events from the Azores and the Cantabrian Cornice. Our findings suggest that C. macrocarpa persisted through the Last Glacial Maximum in two refugia: the Azores and the Cantabrian Cornice. Colonization into new areas occurred presumably from these refuges, generating two large population groups with structured genetic diversity. This study underscores the significance of clonality in establishing new populations and shaping genetic structure.

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KEY MESSAGE: We reported the mitochondrial genome of Ventilago leiocarpa for the first time. Two and one sites lead to the generation of stop and stat codon through editing were verified. Ventilago leiocarpa, a member of the Rhamnaceae family, is frequently utilized in traditional medicine due to the medicinal properties of its roots. In this study, we successfully assembled the mitogenome of V. leiocarpa using both BGI short reads and Nanopore long reads. This mitogenome has a total length of 331,839 bp. The annotated results showed 36 unique protein-coding, 16 tRNA and 3 rRNA genes in this mitogenome. Furthermore, we confirmed the presence of a branched structure through the utilization of long reads mapping, PCR amplification, and Sanger sequencing. Specifically, the ctg1 can form a single circular molecule or combine with ctg4 to form a linear molecule. Likewise, ctg2 can form a single circular molecule or can be connected to ctg4 to form a linear molecule. Subsequently, through a comparative analysis of the mitogenome and cpgenome sequences, we identified ten mitochondrial plastid sequences (MTPTs), including two complete protein-coding genes and five complete tRNA genes. The existence of MTPTs was verified by long reads. Colinear analysis showed that the mitogenomes of Rosales were highly divergent in structure. Finally, we identified 545 RNA editing sites involving 36 protein-coding genes by Deepred-mt. To validate our findings, we conducted PCR amplification and Sanger sequencing, which confirmed the generation of stop codons in atp9-223 and rps10-391, as well as the generation of a start codon in nad4L-2. This project reported the complex structure and RNA editing event of the V. Leiocarpa mitogenome, which will provide valuable information for the study of mitochondrial gene expression.

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BACKGROUND: Beyond the massive amounts of DNA and genes transferred from the protoorganelle genome to the nucleus during the endosymbiotic event that gave rise to the plastids, stretches of plastid DNA of varying size are still being copied and relocated to the nuclear genome in a process that is ongoing and does not result in the concomitant shrinking of the plastid genome. As a result, plant nuclear genomes feature small, but variable, fraction of their genomes of plastid origin, the so-called nuclear plastid DNA sequences (NUPTs). However, the mechanisms underlying the origin and fixation of NUPTs are not yet fully elucidated and research on the topic has been mostly focused on a limited number of species and of plastid DNA. RESULTS: Here, we leveraged a chromosome-scale version of the genome of the orphan crop Moringa oleifera, which features the largest fraction of plastid DNA in any plant nuclear genome known so far, to gain insights into the mechanisms of origin of NUPTs. For this purpose, we examined the chromosomal distribution and arrangement of NUPTs, we explicitly modeled and tested the correlation between their age and size distribution, we characterized their sites of origin at the chloroplast genome and their sites of insertion at the nuclear one, as well as we investigated their arrangement in clusters. We found a bimodal distribution of NUPT relative ages, which implies NUPTs in moringa were formed through two separate events. Furthermore, NUPTs from every event showed markedly distinctive features, suggesting they originated through distinct mechanisms. CONCLUSIONS: Our results reveal an unanticipated complexity of the mechanisms at the origin of NUPTs and of the evolutionary forces behind their fixation and highlight moringa species as an exceptional model to assess the impact of plastid DNA in the evolution of the architecture and function of plant nuclear genomes.

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Genome skimming (shallow whole-genome sequencing) offers time- and cost-efficient production of large amounts of DNA data that can be used to address unsolved evolutionary questions. Here we address phylogenetic relationships and topological incongruence in the tribe Anthospermeae (Rubiaceae), using phylogenomic data from the mitochondrion, the nuclear ribosomal cistron, and the plastome. All three genomic compartments resolve relationships in the Anthospermeae; the tribe is monophyletic and consists of three major subclades. Carpacoce Sond. is sister to the remaining clade, which comprises an African subclade and a Pacific subclade. Most results, from all three genomic compartments, are statistically well supported; however, not fully consistent. Intergenomic topological incongruence is most notable in the Pacific subclade but present also in the African subclade. Hybridization and introgression followed by organelle capture may explain these conflicts but other processes, such as incomplete lineage sorting (ILS), can yield similar patterns and cannot be ruled out based on the results. Whereas the null hypothesis of congruence among all sequenced loci in the individual genomes could not be rejected for nuclear and mitochondrial data, it was rejected for plastid data. Phylogenetic analyses of three subsets of plastid loci identified using the hierarchical likelihood ratio test demonstrated statistically supported intragenomic topological incongruence. Given that plastid genes are thought to be fully linked, this result is surprising and may suggest modeling or sampling error. However, biological processes such as biparental inheritance and inter-plastome recombination have been reported and may be responsible for the observed intragenomic incongruence. Mitochondrial insertions into the plastome are rarely documented in angiosperms. Our results indicate that a mitochondrial insertion event in the plastid trnS GGA - rps4 IGS region occurred in the common ancestor of the Pacific clade of Anthospermeae. Exclusion/inclusion of this locus in phylogenetic analyses had a strong impact on topological results in the Pacific clade.

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Toxoplasma gondii is a zoonotic protist pathogen that infects up to one third of the human population. This apicomplexan parasite contains three genome sequences: nuclear (65 Mb); plastid organellar, ptDNA (35 kb); and mitochondrial organellar, mtDNA (5.9 kb of non-repetitive sequence). We find that the nuclear genome contains a significant amount of NUMTs (nuclear integrants of mitochondrial DNA) and NUPTs (nuclear integrants of plastid DNA) that are continuously acquired and represent a significant source of intraspecific genetic variation. NUOT (nuclear DNA of organellar origin) accretion has generated 1.6% of the extant T. gondii ME49 nuclear genome-the highest fraction ever reported in any organism. NUOTs are primarily found in organisms that retain the non-homologous end-joining repair pathway. Significant movement of organellar DNA was experimentally captured via amplicon sequencing of a CRISPR-induced double-strand break in non-homologous end-joining repair competent, but not ku80 mutant, Toxoplasma parasites. Comparisons with Neospora caninum, a species that diverged from Toxoplasma ~28 mya, revealed that the movement and fixation of five NUMTs predates the split of the two genera. This unexpected level of NUMT conservation suggests evolutionary constraint for cellular function. Most NUMT insertions reside within (60%) or nearby genes (23% within 1.5 kb), and reporter assays indicate that some NUMTs have the ability to function as cis-regulatory elements modulating gene expression. Together, these findings portray a role for organellar sequence insertion in dynamically shaping the genomic architecture and likely contributing to adaptation and phenotypic changes in this important human pathogen.

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A taxonomic treatment of 38 species of Muhlenbergia, a phylogeny based on analysis of six DNA sequence markers, and classification of Muhlenbergia for Central America (Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama; and Campeche, Chiapas, Quintana Roo, Tabasco, and Yucatán, México) is given. With the support from a molecular phylogeny we describe Muhlenbergiasubg.Ramulosaesubgen. nov. In our treatment we place M.gigantea (younger name) as a synonym of M.mutica. Lectotypes are designated for the names Agrostismicrosperma Lag., Epicampesgigantea E. Fourn., Lamarckiatenella DC., Muhlenbergiaadspersa Trin., M.diversiglumis Trin., M.exilis E. Fourn., M.flabellata Mez, M.setarioides E. Fourn., Pereilemaciliatum E. Fourn., P.crinitumvar.cirratum E. Fourn., Podosemumciliatum Kunth, P.tenuissimum J. Presl, and Schellingiatenera Steud.

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Toxoplasma gondii is a zoonotic protist pathogen that infects up to 1/3 of the human population. This apicomplexan parasite contains three genome sequences: nuclear (63 Mb); plastid organellar, ptDNA (35 kb); and mitochondrial organellar, mtDNA (5.9 kb of non-repetitive sequence). We find that the nuclear genome contains a significant amount of NUMTs (nuclear DNA of mitochondrial origin) and NUPTs (nuclear DNA of plastid origin) that are continuously acquired and represent a significant source of intraspecific genetic variation. NUOT (nuclear DNA of organellar origin) accretion has generated 1.6% of the extant T. gondii ME49 nuclear genome; the highest fraction ever reported in any organism. NUOTs are primarily found in organisms that retain the non-homologous end-joining repair pathway. Significant movement of organellar DNA was experimentally captured via amplicon sequencing of a CRISPR-induced double-strand break in non-homologous end-joining repair competent, but not ku80 mutant, Toxoplasma parasites. Comparisons with Neospora caninum, a species that diverged from Toxoplasma ~28 MY ago, revealed that the movement and fixation of 5 NUMTs predates the split of the two genera. This unexpected level of NUMT conservation suggests evolutionary constraint for cellular function. Most NUMT insertions reside within (60%) or nearby genes (23% within 1.5 kb) and reporter assays indicate that some NUMTs have the ability to function as cis-regulatory elements modulating gene expression. Together these findings portray a role for organellar sequence insertion in dynamically shaping the genomic architecture and likely contributing to adaptation and phenotypic changes in this important human pathogen.

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Contamination from cytosolic DNA (plastid and mitochondrion) and epiphytic bacteria is challenging the efficiency and accuracy of genome-wide analysis of nori-producing marine seaweed Pyropia yezoensis. Unlike bacteria and organellar DNA, Pyropia nuclear DNA is closely associated with histone proteins. In this study, we applied Chromatin Immunoprecipitation (ChIP) of histone H3 to isolate nuclear DNA, followed by high-throughput sequencing. More than 99.41% of ChIP-sequencing data were successfully aligned to the reference nuclear genome; this was remarkably higher than those from direct extraction and direct extraction data, in which 40.96% to 42.95% are from plastids. The proportion of data that were mapped to the bacterial database when using ChIP extraction was very low. Additionally, ChIP data can cover up to 89.00% of the nuclear genome, higher than direct extraction data at equal data size and comparable to the latter at equal sequencing depth. The uncovered regions from the three methods are mostly overlapping, suggesting that incomplete sequencing accounts for the missing data, rather than failed chromatin-antibody binding in the ChIP extraction method. This ChIP extraction method can successfully separate nuclear DNA from cytosolic DNA and bacterial DNA, thus overwhelmingly reducing the sequencing cost in a genome resequencing project and providing strictly purified reference data for genome assembly. The method's applicability to other macroalgae makes it a valuable contribution to the algal research community.

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The tree flora of the Mediterranean Basin contains an outstanding taxonomic richness and a high proportion of endemic taxa. Contrary to other regions of the Mediterranean biome, a comprehensive phylogenetic analysis of the relationship between phylogenetic diversity, trait diversity and environmental factors in a spatial ecological context is lacking. We inferred the first calibrated phylogeny of 203 native tree species occurring in the European Mediterranean Basin based on 12 DNA regions. Using a set of four functional traits, we computed phylogenetic diversity for all 10,042 grid cells of 10 × 10 km spatial resolution to completely cover Mediterranean Europe. Then, we tested the spatial influence of environmental factors on tree diversity. Our results suggest that the nature of the relationship between traits and phylogeny varies among the different studied traits and according to the evolutionary distance considered. Phylogenetic diversity and functional diversity of European Mediterranean trees correlated strongly with species richness. High values of these diversity indices were located in the north of the study area, at high altitude, and minimum temperature of the coldest month. In contrast, the two phylogenetic indices that were not correlated with species richness (Mean Phylogenetic Distance, Phylogenetic Species Variability) were located in the south of the study area and were positively correlated with high altitude, soil organic carbon stock and sand soil texture. Our study provides support for the use of phylogenies in conservation biology to assess ecosystem functioning, and provides insights for the implementation of sustainable forest ecosystem management.

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PREMISE: Animal pollinators play an important role in pollen dispersal. Here, we assessed differences in pollen and seed dispersal and the role of pollinator functional groups with different foraging behaviors in generating patterns of genetic diversity over similar geographic ranges for two closely related taxa. We focused on two members of Oenothera section Calylophus (Onagraceae) that co-occur on gypsum outcrops throughout the northern Chihuahuan Desert but differ in floral phenotype and primary pollinator: Oenothera gayleana (bee) and O. hartwegii subsp. filifolia (hawkmoth). METHODS: We measured breeding system and floral traits and studied gene flow and population differentiation at the local (<13 km; four populations) and landscape (60-440 km; five populations) scales using 10-11 nuclear (pollen dispersal) and three plastid (seed dispersal) microsatellite markers. RESULTS: Both taxa were self-incompatible and floral traits were consistent with expectations for different pollinators. Seed and pollen dispersal patterns were distinctly different for both species. We found no evidence of genetic structure at the local scale but did at the landscape scale; O. gayleana showed greater differentiation and significant isolation by distance than in O. hartwegii subsp. filifolia. The plastid data were consistent with gravity dispersal of seeds and suggest that pollen dispersal is the principal driver of genetic structure in both species. CONCLUSIONS: We demonstrated that pollinator functional groups can impact genetic differentiation in different and predictable ways. Hawkmoths, with larger foraging distances, can maintain gene flow across greater spatial scales than bees.

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Autophagy is a highly conserved system that delivers cytoplasmic components to lysosomes/vacuoles. Plastids are also degraded through autophagy for nutrient recycling and quality control; however, the involvement of autophagic degradation of plastids in plant cellular differentiation remains unclear. Here, we investigated whether spermiogenesis, the differentiation of spermatids into spermatozoids, in the liverwort Marchantia polymorpha involves autophagic degradation of plastids. Spermatozoids of M. polymorpha possess one cylindrical plastid at the posterior end of the cell body. By fluorescently labeling and visualizing plastids, we detected dynamic morphological changes during spermiogenesis. We found that a portion of the plastid was degraded in the vacuole in an autophagy-dependent manner during spermiogenesis, and impaired autophagy resulted in defective morphological transformation and starch accumulation in the plastid. Furthermore, we found that autophagy was dispensable for the reduction in plastid number and plastid DNA elimination. These results demonstrate a critical but selective role of autophagy in plastid reorganization during spermiogenesis in M. polymorpha.

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Sequences derived from circular DNA molecules (i.e. most bacterial, viral and plastid genomes) are expected to be linearised and rotated to a common start position for most downstream analyses including alignment. Despite this being a common and straightforward task, available software is either limited to a small number of input sequences, lacks the option to specify a custom anchor string, or requires a commercial license. Here, we present rotate, a simple, open source command line program written in C with no external dependencies, which can rotate a set of input sequences to a custom anchor string (allowing for a specified number of mismatches), or offset the input sequences to the desired position. The combination of both functionalities allows the rotation of all input sequences to any desired starting position, enabling downstream analysis. rotate is extremely fast and scales linearly with the number of input sequences, taking only seconds to rotate over a thousand mitochondrial sequences.

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The delimitation of Limonium taxa is highly complicated due to hybridization, polyploidy, and apomixis. Many "microspecies" were described and aggregated into groups, most of which are still poorly known from both molecular and morphological points of view. The aim of this study is to investigate four endemic species from the Tyrrhenian coast of central Italy and the Ponziane Archipelago belonging to the L. multiforme group (L. amynclaeum, L. circaei, L. pandatariae, and L. pontium) by means of molecular and morphometric analyses. Molecular data by sequencing ITS and three plastid markers and morphometric data highlight new information about the taxonomy of these taxa so as to reduce them into a single specific entity. In fact, the better taxonomic choice is to consider the populations studied as part of a single species, i.e., Limonium pontium. Three subspecies are recognized, i.e., subsp. pontium [= L. circaei = L. amynclaeum; from Circeo to Gianola localities (excluding Terracina) and from islands Ponza, Palmarola, Zannone, and Santo Stefano], subsp. pandatariae comb. et stat. nov. (from island of Ventotene), and subsp. terracinense subsp. nov. (from Terracina).

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Genista etnensis is a remarkable and well-known tree endemic to Sicily, Sardinia, and Corsica (Mediterranean Basin). Nevertheless, its morphological variability and its native status throughout its range need to be further investigated. In this study, we aim to clarify some aspects of this infraspecific variability by molecular means. Sequences of one nuclear and five plastid markers were analyzed under maximum parsimony by using TCS software. Plastid data were also time-calibrated under a Bayesian Inference framework. Plastid data revealed strong isolation between the populations from the Cyrno-Sardinian biogeographical province, which are also the most diverse and presumably the most archaic, and those from Sicily and Southern Italy (in this latter area, the species is naturalized). The calibration analysis indicates that the last common ancestor between G. etnensis and its sister group G. fasselata dates back to the middle Pliocene or slightly later, when sclerophyllous Mediterranean vegetation spread, whereas G. etnensis itself might have originated in the middle Pleistocene. The current, rather unusual distribution of G. etnensis could be explained by long-range seed dispersal from the western part of the range or by anthropogenic introduction into Sicily, with extinctions of transported haplotypes in the region of origin. Interestingly, the Vesuvius population, introduced from Sicily in recent times and locally naturalized, shows private genotypes, and was richer in both genotypes and haplotypes than the Sicilian ones.

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Polymorph Allium pallasii s.l. from monotypic A. sect. Pallasia was studied using a wide spectrum of methods and divided into two clearly morphologically, geographically, cytologically and genetically isolated species: A. pallasii s. str.-North-East Kazakhstan, Western Siberia, and the Altai Mountains; A. caricifolium-Kyrgyzstan, Northwest China, South-East Kazakhstan until Zaysan Lake in the east. Despite serious genetic differences, both species are sisters and are related to species of the A. sect. Codonoprasum (Subg. Allium). Allium caricifolium differs from A. pallasii s. str. by taller stems, dense inflorescence, and with filaments longer than perianth. The possible phylogenetic reasons for the separation of these species are discussed. A nomenclature analysis of synonyms was carried out.

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Viola sect. Melanium, the so-called pansy, is an allopolyploid morphologically well-defined lineage of ca. 110 perennial and annual species in the northern hemisphere, characterized by markedly complex genomic configurations. Five annual pansies occur in Italy, four of which are morphologically very similar and belong to the informal 'V. tricolor species complex': V. arvensis (2n = 34), V. hymettia (2n = 16), V. kitaibeliana (2n = 16), and V. tricolor (2n = 26). Their field recognition is difficult and reflects a long-debated taxonomy often resulting in doubtful records in field inventories and across European herbaria. The current lack of comprehensive intra- and interspecific comparative studies and a relative scarcity of appropriate genetic markers coupled with unambiguous cytological descriptions are hindering clear taxa circumscription and phylogenetic inferences within this group. In this work, we tested DNA sequence variation of three highly variable plastid markers and High-Throughput Sequencing (HTS) of the nuclear ribosomal 5S-IGS region in an attempt to decipher species identity within the V. tricolor species complex and to obtain an insight on their genome organization and evolution. Our results document the close relationships within this species group, a reliable molecular resolution for V. tricolor, and the common ancestry of V. arvensis and the poorly differentiated V. kitaibeliana and V. hymettia. Evidence of an important inter-population geographical divergence was recorded in V. tricolor and V. arvensis, pointing at the existence of different eco-cytotypes within these entities. Overall diversity patterns and the occurrence of two to four differently diverging 5S-IGS lineages are discussed in the light of the acknowledged taxonomy and genomic evolutive trajectories of sect. Melanium.

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Fern phylogeographic studies have mostly focused on the influence of the Pleistocene climate on fern distributions and the prevalence of long-distance dispersal. The effect of pre-Pleistocene events on the distributions of fern species is largely unexplored. Here, we elucidate a hypothetical scenario for the evolutionary history of Vandenboschia speciosa, hypothesised to be of Tertiary palaeotropical flora with a peculiar perennial gametophyte. We sequenced 40 populations across the species range in one plastid region and two variants of the nuclear gapCp gene and conducted time-calibrated phylogenetic, phylogeographical, and species distribution modelling analyses. Vandenboschia speciosa is an allopolyploid and had a Tertiary origin. Late Miocene aridification possibly caused the long persistence in independent refugia on the Eurosiberian Atlantic and Mediterranean coasts, with the independent evolution of gene pools resulting in two evolutionary units. The Cantabrian Cornice, a major refugium, could also be a secondary contact zone during Quaternary glacial cycles. Central European populations resulted from multiple post-glacial, long-distance dispersals. Vandenboschia speciosa reached Macaronesia during the Pliocene-Pleistocene, with a phylogeographical link between the Canary Islands, Madeira, and southern Iberia, and between the Azores and northwestern Europe. Our results support the idea that the geological and climate events of the Late Miocene/Early Pliocene shifted Tertiary fern distribution patterns in Europe.

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In this paper, Allium ducissae (the LSID for the name Allium ducissae is: 77254606-1) is described as a new species based on morphological and molecular analyses, and its taxonomic relationships are discussed. It grows in crevices on calcareous rocks, rocky slopes and grassy ledges in the subalpine belt, within two regional protected areas in the Lazio and Abruzzo administrative regions (Central Apennines, Italy). Previously, these populations were attributed to A. strictum, a species described from Siberia, belonging to A. sect. Reticulatobulbosa. The new species is distinct from A. strictum in the morphology of vegetative and reproductive structures. Indeed, it is close to A. palentinum, an endemic species to Cantabrian Mountains (NW Spain). Both molecular and morphological data support the recognition of the Allium populations coming from the Central Apennines as a new species. Allium ducissae can be clearly distinguished from A. palentinum by longer and wider tepals, longer filaments, tooth of inner filament, flower pedicels, spathe appendage, and smaller seeds. Moreover, seed testa micro-sculptures revealed slight differences between A. ducissae and A. palentinum. Chromosome counts showed that A. ducissae is diploid with 2n = 16 chromosomes, as already known for A. palentinum. Molecular analyses support the affiliation of A. ducissae and A. palentinum to A. sect. Falcatifolia, contrary to what is known for the latter species, usually included in A. sect. Daghestanica. Finally, the IUCN assessment for the newly described species is proposed and briefly discussed.