The knowledge of the genetic architecture of closely related species and/or populations of a single species can be very useful to shed light on the processes that led to their current distributions. The present study provides a preliminary evaluation of the conservation status of the populations of Cryptotaenia thomasii, a very narrow endemic species occurring in southern Italy. Previous studies showed that C. thomasii was phylogenetically closely related to C. flahaultii, endemic species of Caucasus, and to evaluate its conservation status and the genetic variability of plant species the internal transcribed spacers (ITSs) of nuclear ribosomal DNA were sequenced and the SNPs were analyzed. The restriction analysis of nrDNA with the restriction enzymes allowed to detect the presence of two single mutations (SNPs) among the sequences of two species. Our molecular analysis pointed out that C. thomasii and C. flahaultii, in spite of their geographical disjunction, show a sign of an ancient contact as an extreme case of geographical disjunction Italian-Caucasus. From the evolutionary history of the species and its distribution pattern one can reconstruct a possible scenario with some hypotheses that explain the hypothetical ancestral area where the two species were in contact. We speculate the two species may have originated from fragmentation of a common ancestor widespread in the Western Palearctic zone and have survived in two separated refuge areas limited by important mountain systems. This hypothesis is supported by our molecular analysis, in fact, the analysis of SNPs showed that some C. thomasii populations retain the signs of an ancient link with C. flahaultii.

We quantified inbreeding depression for fruit production, embryo vitality and seed germination in three deceptive orchids, Serapias vomeracea, S. cordigera and S. parviflora, which do not provide any reward to their pollinators, and are predicted to experience high outcrossing. Of the three species examined only S. parviflora was autonomously selfing. Both S. vomeracea and S. cordigera showed highly significant differences in fitness between selfed and outcrossed progenies, resulting in high levels of inbreeding depression, which increased in magnitude from seed set to seed germination. Inbreeding depression may promote outcrossing in Serapias by acting as a post-pollination barrier to selfing. Cumulative inbreeding depression across three stages in S. parviflora was lower that in both outcrossing species. The large difference in germination between selfed and outcrossed seeds is an important issue in conservation biology.

Polygonum is the largest genus of Polygonaceae and 5 species are reported in Tunisia. In order to characterized flower, seed, and fruit development in Polygonum, flower and fruit of Polygonium equisetiforme (var. graecum and peyerinhoffi), P. aviculare and P. maritimum, collected from Tunisia, were examined. Flowers are composed of five oblong tepals. P. equisetiforme and P. aviculare have whitish-pink distylous flowers with dimorphism of style, filament and anther height, pollen diameter and stigma size. In contrast, P. maritimum shows white homostylous flowers. The floral vasculature showed that the tepals are inserted in one whorl and their traces arise independently in 3+2 manner. The eight stamens are arranged in a 5+3 manner and the staminal bundles arise independently in the two whorls. The epidermis and endothecium cells width were higher in P. maritimum and the lowest endothecium width was observed in P. aviculare. Polygonum aviculare and P. equisetiforme showed circular pollen with shallow colpi and trilobite pollen shape with deep colpi, while P. maritimum rarely showed shallow colpi. The ovule is anatropous with basal placentation in P. equisetiforme and P. aviculare and apical placentation in P. maritimum. The young seed coat was formed by an endotesta with thick-walled cells, a mesotesta and exotesta with thin-walled cells and a tegmen composed of radially elongated cells. The fruits of the studied species are trigonous with ovate-lanceolate shape. In P. aviculare, the exocarp is thicker compared to the two other species, in P. equisetiforme, the mature exocarp consists of smaller rectangular cells with narrow cavities, and in P. maritimum showed a thinner exocarpIn conclusion, P. equisetiforme and P. aviculare are a typically distylous species from the morphological point of view and we discussed the significance of heterostyly in Polygonaceae. From this first morpho-anatomical study of Polygonum species in North Africa, we can conclude mainly that there is no significant difference between P. equisetiforme var. graecum and var. peyerinhoffi supporting a taxonomic grouping of these two varieties.