Integrative revision of Dianthus superbus subspecies reveals different degrees of differentiation, from plasticity to species distinction

Weak Genetic Isolation and Putative Phenotypic Selection in the Wild Carnation Dianthus virgineus (Caryophyllaceae)

By relating genetic divergence at neutral loci, phenotypic variation, and geographic and environmental distances, it is possible to dissect micro-evolutionary scenarios involving natural selection and neutral evolution. In this work, we tested the patterns of intraspecific genetic and phenotypic variation along an elevational gradient, using Dianthus virgineus as study system. We genotyped genome-wide SNPs through ddRAD sequencing and quantified phenotypic variation through multivariate morphological variation. We assessed patterns of variation by testing the statistical association between genetic, phenotypic, geographic, and elevational distances and explored the role of genetic drift and selection by comparing the Fst and Pst of morphometric traits. We revealed a weak genetic structure related to geographic distance among populations, but we excluded the predominant role of genetic drift acting on phenotypic traits. A high degree of phenotypic differentiation with respect to genetic divergence at neutral loci allowed us to hypothesize the effect of selection, putatively fuelled by changing conditions at different sites, on morphological traits. Thus, natural selection acting despite low genetic divergence at neutral loci can be hypothesized as a putative driver explaining the observed patterns of variation.

Genome Size Variation in Dianthus sylvestris Wulfen sensu lato (Caryophyllaceae)

Genome size (GS) is an important characteristic that may be helpful in delimitation of taxa, and multiple studies have shown correlations between intraspecific GS variation and morphological or environmental factors, as well as its geographical segregation. We estimated a relative GS (RGS) of 707 individuals from 162 populations of Dianthus sylvestris with a geographic focus on the Balkan Peninsula, but also including several populations from the European Alps. Dianthus sylvestris is morphologically variable species thriving in various habitats and six subspecies have been recognized from the Balkan Peninsula. Our RGS data backed-up with chromosome counts revealed that the majority of populations were diploid (2n = 30), but ten tetraploid populations have been recorded in D. sylvestris subsp. sylvestris from Istria (Croatia, Italy). Their monoploid RGS is significantly lower than that of the diploids, indicating genome downsizing. In addition, the tetraploids significantly differ from their diploid counterparts in an array of morphological and environmental characteristics. Within the diploid populations, the RGS is geographically and only partly taxonomically correlated, with the highest RGS inferred in the southern Balkan Peninsula and the Alps. We demonstrate greater RGS variation among the Balkan populations compared to the Alps, which is likely a result of more pronounced evolutionary differentiation within the Balkan Peninsula. In addition, a deep RGS divergence within the Alps likely points to persistence of the alpine populations in different Pleistocene refugia.

Typification of 14 names in the Dianthusvirgineus group (Caryophyllaceae)

The nomenclature of 14 taxa from Central and Southern Europe within the Dianthusvirgineus group is discussed. Dianthusaggericola Jord., D.collivagus Jord., D.consimilis Jord., D.orophilus Jord., D.saxicola Jord., D.juratensis Jord. are here lectotypified by specimens from the Jordan herbarium in LY, while D.godronianus Jord. by a specimen in P. Dianthussubacaulis Vill. is neotypified by a specimen collected on Mont Ventoux (S. France) and housed in MPU. For D.sylvestris Wulfen, a lectotype is here designated and its previous neotypification is discussed. Dianthuscaryophyllusvar.tenuifolius Moris, D.caryophyllusf.minor Moris and D.sylvestrisvar.garganicus Ten. are lectotypified by specimens housed in herbarium Moris (TO) and herbarium Tenore (K). Dianthusvirgineusvar.tergestinus Rchb. is lectotypified by a drawing from the Icones florae Germanicae & Helveticae, while D.contractusvar.evolutus Lojac. is neotypified by a specimen in P. For each taxon the currently accepted name is provided including new synonymies. The type indication is followed by nomenclatural and taxonomic notes, in which the original material found is commented and the reasons for the identification of the types are discussed.

Dianthus superbus as a critically endangered species in Latvia: evaluation of its growth conditions and conservation possibilities

Dianthus superbus is one of the most endangered species in Latvia and is on the verge of local extinction. Therefore, the aim of this study was to inventory previously identified populations of D. superbus in Latvia and to develop activities to conserve this species in accordance with the results obtained in situ. Expeditions on 18 previously documented locations, according to the data of Nature Conservation Agency, revealed only three existing D. superbus localities in Latvia with a significant number of specimens located in the Latgale region near Silenieki. In 2020, for the first time, two more new D. superbus localities were found in the vicinity of these three approved locations. As it is not possible to create micro-reserves in the existing localities which are mainly located either on roadsides or in a cemetery, additional activities are needed to preserve the D. superbus in Latvia. In vitro culture was initiated from shoot explants obtained in situ, from which, in turn, ex vitro plantings were done in the National Botanic Garden (NBG) and the Botanical Garden of the University of Latvia (BG UL). Their quality and compliance with plants in situ were analysed. Overall, it was concluded that the plants grown ex situ were qualitatively equivalent to those obtained in situ, as a very high percentage of seed viability and germination was found both for in situ and ex situ growing D. superbus. Based on the results obtained we could conclude that D. superbus is a species that is able to adapt to different soils with a wide range of nutrient levels, moisture conditions and pH, as long as there are three main preconditions-adequate lighting, low overgrowth of other plant species and non-destructive human activities.