On the basis of the phylogenetic analyses, 19 monophyletic genera are accepted within Ornithogaloideae: Albuca, Avonsera, Battandiera, Cathissa, Coilonox, Dipcadi, Eliokarmos, Elsiea, Ethesia, Galtonia, Honorius, Loncomelos, Melomphis, Neopatersonia, Nicipe, Ornithogalum, Pseudogaltonia, Stellarioides and Trimelopter. Each of these has a particular syndrome of morphological characters. As a result, 105 new combinations are made and two new names are proposed to accommodate the taxa studied in the new arrangement. A short morphological diagnosis, synonymy, details of distribution and an identification key are presented.
Medicago citrina is an endangered western Mediterranean endemic that grows only on small islets of the Balearic archipelago and off the eastern Spanish coast. Only 10 isolated subpopulations are currently known (four from Ibiza, three from Cabrera, two from Columbretes and one from an offshore islet in northern Alicante province), constituting a severely fragmented genetic system. Data were analysed with the unweighted pair-group method using arithmetic averages (UPGMA) and principle coordinates analysis (PCOA), revealing several distinct groups. Genetic diversity indices indicated that Ibizan subpopulations had the highest genetic variability (Nei's index: 0.1463; Shannon's index: 0.228), whereas the lowest variability was found in Alicante (Nei's index: 0.035; Shannon's index: 0.050) and Cabrera (Nei's index: 0.068; Shannon's index: 0.104). These latter populations show the highest FST values (FST = 0.548) revealing high differentiation between them. Columbretes subpopulations formed a defined single group, although it also included some Ibizan samples. The smallest FST values, obtained between Ibiza and Columbretes (FST = 0.185), are not correlated with geographical proximity, but appear to be related to the geologically recent volcanic origin of the Columbretes islands (300,000 years ago). According to the distribution of the Ibizan samples in the dendrogram and the FST values, the best hypothesis is to regard the Ibizan subpopulations as the centre of genetic diversity of the currently known subpopulations. Our results suggest migratory scenarios from Ibiza to Columbretes based mainly on zoochory probably by seabirds. Finally, recommendations are provided for management strategies to facilitate the conservation of this endangered species.
Summary
Floral nectar spurs are widely considered a key innovation promoting diversification in angiosperms by means of pollinator shifts. We investigated the macroevolutionary dynamics of nectar spurs in the tribe Antirrhineae (Plantaginaceae), which contains 29 genera and 300–400 species (70–80% spurred). The effect of nectar spurs on diversification was tested, with special focus on Linaria, the genus with the highest number of species.
We generated the most comprehensive phylogeny of Antirrhineae to date and reconstructed the evolution of nectar spurs. Diversification rate heterogeneity was investigated using trait‐dependent and trait‐independent methods, and accounting for taxonomic uncertainty. The association between changes in spur length and speciation was examined within Linaria using model testing and ancestral state reconstructions.
We inferred four independent acquisitions of nectar spurs. Diversification analyses revealed that nectar spurs are loosely associated with increased diversification rates. Detected rate shifts were delayed by 5–15 Myr with respect to the acquisition of the trait. Active evolution of spur length, fitting a speciational model, was inferred in Linaria, which is consistent with a scenario of pollinator shifts driving diversification.
Nectar spurs played a role in diversification of the Antirrhineae, but diversification dynamics can only be fully explained by the complex interaction of multiple biotic and abiotic factors.
Tamarix is one of the taxonomically most complex genera among the angiosperms, and there is little consensus regarding its infrageneric classification. Here we present the most complete phylogenetic reconstruction of the genus to date. This includes a DNA phylogenetic tree based on nuclear ribosomal ITS, and a plastid DNA phylogeny based on three intergenic spacers (trnS-trnG, ndhF-rpl32, and trnQ-rps16). In total, both nuclear and plastid phylogenetic analyses include more than 70 samples of 39 species from 27 countries, which represent close to 60% of the diversity of the genus. Two complementary trees, based only on one plastid marker, are also included. The first, based on trnS-trnG, is used to increase the number of species related to T. amplexicaulis. The second, based on ndhF-rpl32, is used to investigate the separation between T. tetrandra and T. parviflora. The incongruence between the available infrageneric classifications and the molecular results is confirmed. A reticulate evolution is inferred from the trees, showing characters such as vaginate leaves appearing at different stages along the evolutionary history of the genus. The presence of T. canariensis outside the Canary Islands is cast into doubt, and all such records from NW Africa and Europe are here considered to belong to T. gallica. The results also suggest independence of T. karelinii from T. hispida, and T. parviflora from T. tetrandra. Relationships between a number of species are still not resolved, and additional studies will be needed to further refine the complex taxonomy of Tamarix.
Seed shape in Silene species is often described by means of adjectives such as reniform, globose, and orbicular, but the application of seed shape for species classification requires quantification. A method for the description and quantification of seed shape consists in the comparison with geometric models. Geometric models based on mathematical equations were applied to characterize the general morphology of the seeds in 21 species of Silene. In addition to the previously described four models (M1 is the cardioid, and M2 to M4 are figures derived from it), we present four new geometric models (model 5–8). Models 5 and 6 are open cardioids that resemble M3, quite different from the flat models, M2 and M4. Models 7 and 8 were applied to those species not covered by models 2 to 6. Morphological measures were obtained to describe and characterize the dorsal view of the seeds. The analyses done on dorsal views revealed a notable morphological diversity and four groups were identified. A correlation was found between roundness of dorsal view and the geometric models based on lateral views, such that some of the groups defined by seed roundness are also characterized by the similarity to particular models. The usefulness of new morphological tools of seed morphology to taxonomy is discussed.
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