The 21 wild species of Phalaris L. (Poaceae) are distributed in temperate areas of both hemispheres and in the mountains of tropical Africa and South America. The genus contains annual and perennial diploids based on x = 6 and 7 and polyploids based on x = 7, with the x = 6 cytotypes displaying less species diversification. Phalaris presents a potentially valuable case study for speciation in conjunction with chromosomal evolution and biogeography in Poaceae due to its global distribution, notable variation in morphological traits, and the key role of polyploidy in its evolution. We reconstructed the first phylogenetic tree for the genus using nuclear ITS and plastid trnT‐F sequences to assess species relationships and map trends in floret differentiation and patterns of polyploid evolution. The study demonstrated a single origin of the x = 6 chromosome number and revealed the sister relationship of this lineage to the monophyletic x = 7 lineage. The clades recovered in the analyses display geographic affiliations and demonstrate diploid‐polyploid associations. A trend in sterile lemma reduction is evident, with members of the early diverging x = 6 lineage displaying relatively large and lanceolate sterile lemmas, followed by gradual reduction in size, culminating in almost obsolete sterile lemmas in one of the terminal x = 7 clades.

The small, annual grass Brachypodium distachyon (L.) Beauv., a close relative of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.), is a powerful model system for cereals and bioenergy grasses. Genome-wide association studies (GWAS) of natural variation can elucidate the genetic basis of complex traits but have been so far limited in B. distachyon by the lack of large numbers of well-characterized and sufficiently diverse accessions. Here, we report on genotyping-by-sequencing (GBS) of 84 B. distachyon, seven B. hybridum, and three B. stacei accessions with diverse geographic origins including Albania, Armenia, Georgia, Italy, Spain, and Turkey. Over 90,000 high-quality single-nucleotide polymorphisms (SNPs) distributed across the Bd21 reference genome were identified. Our results confirm the hybrid nature of the B. hybridum genome, which appears as a mosaic of B. distachyon-like and B. stacei-like sequences. Analysis of more than 50,000 SNPs for the B. distachyon accessions revealed three distinct, genetically defined populations. Surprisingly, these genomic profiles are associated with differences in flowering time rather than with broad geographic origin. High levels of differentiation in loci associated with floral development support the differences in flowering phenology between B. distachyon populations. Genome-wide association studies combining genotypic and phenotypic data also suggest the presence of one or more photoperiodism, circadian clock, and vernalization genes in loci associated with flowering time variation within B. distachyon populations. Our characterization elucidates genes underlying population differences, expands the germplasm resources available for Brachypodium, and illustrates the feasibility and limitations of GWAS in this model grass. Core Ideas• Genotyping diverse Brachypodium accessions expands research tools for grasses.• The B. hybridum genome is a mosaic of B. distachyonand B. stacei-like sequences.• Three distinct, genetically defined populations of B. distachyon were identified.• Flowering time, more than geography, distinguishes B. distachyon populations.• Results support the feasibility of genome-wide association studies in a model grass.

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SummaryTragopogon includes two classic examples of recently formed allopolyploid species in North America: T. mirus and T. miscellus. Older Tragopogon allotetraploids from Eurasia offer ideal taxa for comparing the longer term outcomes of allopolyploidy.To help resolve the ancestry of one of these older polyploids, phylogenetic analyses of multiple populations of the allotetraploid T. castellanus (2n = 24) and its putative diploid parents, T. crocifolius and T. lamottei, were conducted using sequences from nuclear (internal transcribed spacer, ITS; and alcohol dehydrogenase 1A, Adh) and plastid (trnT-trnL spacer, trnL intron, trnL-trnF spacer and rpl16 intron) loci. Fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH) were used to investigate the chromosomal constitution of T. castellanus.Our data confirm that the widely distributed T. crocifolius and the Iberian endemic, T. lamottei, are the diploid parents of T. castellanus, and that this polyploid formed at least three times.One group of populations of T. castellanus is distinct in exhibiting two pairs of rearranged chromosomes. These data suggest that some of the chromosomal variants that originate in young polyploids (here, an intergenomic translocation) may become fixed in populations, contributing to novelty in older polyploid lineages. The geographical distributions of the allopolyploids and parents are also complex, with allotetraploid populations being disjunct from one or both of the most closely related diploid parental populations.

Accettato per Ia stampa il 22 Luglio 1992Il genere Phalaris L. (Gramineae) in Italia. -ll presente lavoro ha permesso di individuare 10 specie rispetto aile 8 riportate dalle ultime Flore Italiane: P. arundinacea L., P. rotgesii (Husnot) Baldini stat. nov., P. aquatica L., P. birtiglumis (Trabut) Baldini stat. nov., P. minor Retz., P. coerulescens Des£., P. paradoxa L., P. truncata Guss. ex Bert., P. canariensis L., P. brachystachys Link. Viene discussa la variabilita ploidica e fenetica. Quest'ultima e valutata al fine di chiarirne la trattazione formale e tassonomica e di individuare i caratteri diacritico-analitici. P. hirtiglumis e nuova non solo per l'Italia, rna anche per l'intero territorio europeo. P. truncata e P. rotgesii si rivelano come le specie a maggiore selettivita ecologica.The genus Phalaris L. has had a complicated taxonomic and nomenclatural history. Both LINNAEUS (1754) and LAMARCK (1783) defined the genus on the basis of inflorescence morphology, particularly the glumes. TRINIUs (1828) and KuNTH (1829) recognised the important distinction between sterile and fertile florets producing improved classifications. KuNTH (1833) treated the species under three categories «species genuinae» (10 species), <

The Mediterranean islands support a rich diversity of flora, with a high percentage of endemic species. We used the IUCN categories and criteria to assess the conservation status of 16 endemic plant taxa (species and subspecies) of the Tuscan Archipelago, based on data collected during field surveys over 4 years. Our data were sufficient to use criteria B, C and D in our assessment. We used criterion B in the assessment of all 16 taxa, criterion C for four taxa, criterion D for 11 taxa and criteria B, C and D for three taxa, Centaurea gymnocarpa, Limonium doriae and Silene capraria. According to our results L. doriae, Romulea insularis and S. capraria are categorized as Critically Endangered and therefore require immediate conservation measures; eight taxa are categorized as Endangered, two as Vulnerable and three as Near Threatened. Compared to earlier assessments, eight species are recategorized with a higher degree of threat, two species are recategorized with a lower degree of threat, five are unchanged, and one species is assessed for the first time. Based on the IUCN categorization our results show that all the endemic species of the Tuscan Archipelago are directly and/or indirectly threatened by human activities, such as tourism and agriculture, and invasive species of plants and animals. The Tuscan Archipelago National Park is responsible for the conservation of all endemic species in the area