Critical forms in Sicilian populations of annual Lysimachia L. (Primulaceae)

Abstract

Based on recent literature, in the Primrose family the genus Lysimachia L. absorbed Anagallis L. (1). As a result, new name combinations have been introduced for this genus, thus involving the increase of specific and intraspecific taxa (for Italian flora see 2 and 3). A further consequence, focused in this contribution, concerns the binomial combination Lysimachia arvensis (L.) U.Manns & Anderb., which has different synonyms and includes several specific and intraspecific taxa. As far as the taxonomic history of the annual taxa of Anagallis is concerned, different authors preferred to include some of them in A. arvensis and in A. foemina at the level of variety (4) or subspecies (2), while others recognized their specific rank (5, 6, 7). Among these taxa, A. parviflora Hoffmanns. & Link is frequently reported, even included among the synonyms of A. arvensis (5) and then considered as a distinct species (7). The already complex status is further complicated by the occurrence of hybrids, as reported by Pignatti (6). The cited case would regard A. foemina and A. parviflora, but other taxa are also mentioned in literature [cf. Anagallis × intermedia Giraudias = Lysimachia × intermedia (Giraudias) B.Bock [(Lysimachia arvensis (L.) U.Manns & Anderb. × Lysimachia foemina (Mill.) U. Manns & Anderb.]. The analysis of the variability observed in a Sicilian population referable to this group (Fig. 1) revealed a quite critical case, introducing additional variables in the different interpretations of varieties, forms and hybrids of this group of complex species. Plant samples collected in the territory of Palermo particularly showed new colours of the corolla and different dimensions of petals. This recurrence of form and colour observed in the same station for two years, with the presence of congeneric taxa, allows to hypothesize a temporary recurrence of the mentioned features; the authors were induced to interpret this population at variety level or consider it the result of recurringhypothesize a temporary recurrence of the mentioned features; the authors were induced to interpret this population at variety level or consider it the result of recurring hybridization processes. Field researches were extended on this basis and a second population was found in the territory of Misilmeri, near Palermo. Both populations coexist with the best known and widespread A. arvensis (incl. A. phoenicea Scop.) and A. foemina. The possible hybrid origin of the new type – elsewhere reported by amateurs not just in Italy – led to start genetic investigations which are still in progress.