Morphology, geometric morphometrics, and taxonomy in relict deciduous oaks woods in northern Italy

Abstract

The Euganean Hills are a well-known refugee site for thermophilous woody flora in northern Italy. Among the species recorded here, there is Quercus dalechampii. The Euganean Hills are the only northern Italy site where the occurrence of this oak species is considered. The aim of this paper was to verify the presence of Q. dalechampii in the study area and to select possible diagnostic morphological traits that are usable to distinguish it from Q. petraea and Q. pubescens. Forest stands dominated by Q. petraea, Q. pubescens, and the presumed Q. dalechampii were sampled using the phytosociological approach to highlight their ecological features. Leaf and fruit material from 104 oak individuals was analysed from a macro-morphological and micro-morphological point of view. Leaf shape was also analysed using the geometric morphometric approach. All multivariate analysis procedures applied on the matrices of leaf and fruit traits highlighted two main clusters of morphological diversity. One was restricted to Q. pubescens individuals, and the other one was a mix of Q. petraea and presumed Q. dalechampii individuals. According to the twig and leaf trichome traits, all presumed Q. dalechampii individuals were classified as belonging to the Q. petraea collective group. Morphological differences between Q. petraea and presumed Q. dalechampii were considered not significant. In conclusion, the occurrence of a third oak species, in addition to Q. petraea and Q. pubescens, was not confirmed for the study area by the results of this paper. Graphic abstract

Leaf morphometric analysis and potential distribution modelling contribute to taxonomic differentiation in the Quercus microphylla complex

“…Recently, the need to adopt methodologies for taxonomic purposes based on data from several individuals and different populations has been highlighted, mainly due to the variation that individuals or populations may present (Di Pietro et al 2020 ). Such variation arises as a result of phenotypic plasticity or local adaptation to the different environments in which populations develop, sometimes leading to the formation of ecomorphotypes, potentially causing a taxonomic overestimation of the number of species (Di Pietro et al 2020 ; Proietti et al 2021 ). At the other extreme, the number of species can be underestimated because of morphological similarities, as reported by Morales-Saldaña et al ( 2022 ) for the Q. laeta complex, with a large number of morphotypes and synonymies within it, which may correspond to different species.…”

Chloroplast Haplotype Diversity in the White Oak Populations of the Italian Peninsula, Sicily, and Sardinia

“…Forests 2024, 15, x FOR PEER REVIEW 3 of 31 contribute to the creation of more informed sampling designs for future genomic studies and to a better interpretation of recent [26,27,53] and ongoing works [54] on white oaks' diversity. We will address the following questions: (i) Is it possible to correlate the distribution of haplotypes in natural white oak forests in Italy with biogeographical patterns?…”

“…Our study carries out a new and updated analysis of the cpDNA variability of white oak populations of the Italian Peninsula, Sicily, and Sardinia using cpSSRs in order to fill the existing gap and upgrade the dated diversity structure currently available. The data obtained will contribute to the creation of more informed sampling designs for future genomic studies and to a better interpretation of recent [26,27,53] and ongoing works [54] on white oaks' diversity. We will address the following questions: (i) Is it possible to correlate the distribution of haplotypes in natural white oak forests in Italy with biogeographical patterns?…”

Morphometric Analyses of Leaf Shapes in Four Sympatric Mediterranean Oaks and Hybrids in the Algerian Kabylie Forest

“…The use of leaf morphology traits has allowed the analysis of the complex genetic structure in populations of this group of species [29][30][31][32]. Leaf morphological traits are highly variable among species [11,33], and can be used to discriminate among them [34]. It has been shown that a morphological classification [21,35,36] has a clear correspondence with the genetic assignment of individuals.…”