No abstract

The origin and evolution of alpine biota are not yet fully understood, particularly in the vast Asian mountain regions. In addition, in these regions, most studies have concentrated on taxa occurring in areas benefitting from relatively generous rainfall from the summer monsoon. In this study, we collected a large number of Oxytropis species throughout their distribution range, and investigated the taxonomy and evolution of this diverse legume genus, which also occurs in mountainous areas prone to drought. Using nuclear (ITS) and plastid (trnL‐F) markers, we reconstructed phylogenetic relationships within Oxytropis, conducting maximum parsimony, fasttree‐like, maximum likelihood, Bayesian, and BEAST analyses. We also used Anchored Hybrid Enrichment (AHE) to test the power of this method to resolve relationships among a small subset of Oxytropis species. For AHE, we sampled eight species and obtained 527 low‐copy and orthologous nuclear loci. We show that the taxonomy of this genus that radiated explosively in Asian mountains will remain recalcitrant based on conventional molecular methods. Because of a severe lack of resolution, none of the available taxonomic treatments for Oxytropis could either be confirmed or refuted based upon ITS and trnL‐F. Nevertheless, we confirm the status of several species, and identify morphological or genetic particularities for some groups of species. The AHE approach yielded a highly supported phylogenetic tree, suggesting that increased taxon sampling coupled with AHE methods promise advances in the study of the taxonomy and evolution of Oxytropis, thus providing further analytical opportunities, such as diversification rate and biogeographical analyses.

Pollen morphology of 11 species of the genus Oxytropis DC. (Fabaceae) distributed in Turkey were examined with light (LM) and scanning electron microscope (SEM). Morphology of pollen grains shows isopolar, radially symmetric, tricolporate, prolate or subprolate, porus shape oblate or operculate and exine subtectate. The size varies with the polar axis from 19.52 -33.31 µm and the equatorial axis from 13.50 -25.82 µm. There are five ornamentation types: perforate at equatorial section and psilate at polar sections, microreticulate at equatorial sections and psilate at polar sections, microreticulate at equatorial sections and perforate at polar sections, microreticulate at both equatorial and polar sections and perforate at both equatorial and polar sections. Pollen aperture, shape and especially different ornamentation patterns at polar and equatorial section of pollen, as found in this study, appear to be important character. The findings of this study indicate the taxonomic implications of pollen morphology in understanding the similarity and relationships in the genus Oxytropis.

In the present study, seeds of 13 Oxytropis DC. species (including two latest synonyms) classified in subg. Oxytropis (sect. Dolichocarpon, sect. Chrysantha and sect.Eumorpha), subg. Euoxytropis (sect. Orobia), and subg. Phacoxytropis (sect.Protoxytropis, sect. Janthina and sect. Mesogaea) from Turkey were examined using Light and Scanning Electron Microscopy to evaluate the taxonomic relevance of macroand micro-morphological seed characters. As a result of the study, species-specific characters have been determined. Seeds exhibit variation in size, shape, surface sculpturing pattern, hilum position and weight. Seeds ranged from 1.61 to 4.04 mm in length and 1.02 to 2.56 mm in width. Five different seed shapes were recognized, as prolonged semielliptic, reniform, prolonged reniform, quadratic and cardiform, with a length to width ratio ranging from 1.02 ± 0.08 to 1.75 ± 0.27. Rugulate, rugulatereticulate and lophate sculpturing patterns were observed in the studied species.According to the results, seed characters, such as the size (length, width and the A c c e p t e d M a n u s c r i p t length/width ratio), the shape, the surface sculpturing and the weight appear to have low taxonomic value in distinguishing subgenera, sections and species.

Literature studies of taxa belonging to the genus Astragalus have revealed that there are too few karyotype analyses of this genus. To eliminate deficiencies, somatic chromosome morphologies were identified for 25 taxa belonging to the genus Astragalus that grow naturally in Turkey, and chromosome morphology differences were described. These taxa are A. oleaefolius DC.,