Phenotypic correlates of genetic divergence suggest at least three species in the complex of Dianthus virgineus (Caryophyllaceae)

Abstract

Dianthus virgineus encompasses a very complex taxonomic group (traditionally called D. sylvestris group) including an array of units of doubtful taxonomic rank and value. Recent work identified three genetic lineages within this complex that showed strong genetic isolation, and clear geographical boundaries (i.e., “Alpine”, “Balkan”, and “Apennine” lineages). We evaluated the contribution of 33 morphological characters in differentiating such genetic units, by also investigating the effect of geographical and ecological drivers on the characters showing major discriminating power. The morphological measures were taken from a large number of populations (N = 97) included in the sample used for detecting the three genetic lineages. Our work reveals that these lineages can be morphologically discriminated by a series of character‐states that are traditionally considered of relevant taxonomical value. We also inferred a significant geographical and ecological effect on most characters, which varied gradually with latitude, longitude, and mean annual temperature. Overall, our data suggest that the three biological units can be referred to D. inodorus (L.) Gaertn. (“Alpine” lineage), D. sylvestris Wulfen (“Balkan” lineage), and D. virgineus L. s.str. (“Apennine” lineage). We also provide an identification key to discriminate these three taxa.

A cytosystematic study of the Dianthus virgineus complex (Caryophyllaceae) in the Central Mediterranean

“…Rouy, where Balkan populations had smaller GS compared to those from the Apennines (Frajman et al, 2015). Overall, the RGS variation within the D. virgineus complex across the Alpine, Apennine, and Balkan regions parallels the temporal sequence of divergences among the three genetic lineages (Luqman et al, 2023), which have also been shown to be morphologically differentiated (Gargano et al, 2023). Early divergent "Balkan" lineage has smaller genome compared to the "Alpine" and the "Apennine" lineages.…”

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

“…We measured 24 quantitative variables regarding vegetative organs (leaves and stems) and reproductive structures (corolla and petals, calyx, anthers, ovaries, epicalyx scales) (Table 1). These characters are known to vary among and within different species belonging to the D. virgineus complex [39,42,72]. Moreover, in many species of Dianthus, the variation in traits such as plant height, leaf dimensions, and calyx length is known to be associated with climatic variation and oscillations [39,72,73] and subjected to local adaptation, driven by abiotic factors, at different elevations [74].…”

“…These characters are known to vary among and within different species belonging to the D. virgineus complex [39,42,72]. Moreover, in many species of Dianthus, the variation in traits such as plant height, leaf dimensions, and calyx length is known to be associated with climatic variation and oscillations [39,72,73] and subjected to local adaptation, driven by abiotic factors, at different elevations [74]. Seven variables were measured on fresh materials, and the remaining on the same individuals after being prepared as herbarium specimens (Table 1).…”

“…For instance, high-elevation ecotypes, characterized by reduced plant size, have also been observed in D. carthusianorum L. in the Swiss Alps [74]. On broader geographic and evolutionary scales, a study correlating multivariate morphometric variation with environmental variability among genetically separated lineages in the D. virgineus complex proved that increasing elevation and decreasing temperature are negatively associated with the traits determining plant biomass (e.g., stalk size and leaf width) [39].…”

“…In this work, we explored the patterns of intraspecific genetic and phenotypic variation along an elevational gradient using Dianthus virgineus L. [36], an outcrossing perennial plant species, as the study system. Dianthus virgineus is a Mediterranean species of wild carnations, mainly distributed in southern France and the Italian Peninsula, occurring along a wide elevational range [37][38][39]. Populations of D. virgineus belong to a genetically uniform, recently originated (114-132 kya) evolutionary lineage [40].…”