The genetic diversity and phylogenetic relationships of Oxytropis caespitosa, O. grandiflora, O. eriocarpa, O. mixotriche, O. nitens, O. peschkovae and O. triphylla, section Xerobia subgenus Oxytropis, in one of the main speciation centres of the genus Oxytropis (Baikal Siberia and adjacent territories of Northeastern Mongolia) were studied based on sequence analysis of the psbA–trnH, trnL–trnF and trnS–trnG intergenic spacers of cpDNA, as well as the ITS nrDNA. Most populations are characterized by a high level of chloroplast genetic diversity (h varied from 0.327 to 1.000 and π from 0.0001 to 0.0090) due to the ancient origin for some species and to hybridization and polyploidy for others. 67 haplotypes were identified, of which six were shared. Phylogenetic relationships among species could not be satisfactorily resolved. Only the haplotypes of O. triphylla formed a group with rather high support. Probably, O. caespitosa, O. grandiflora, O. mixotriche and O. nitens constitute a single genetic complex. As regards the ITS nrDNA polymorphism, we detected only two ribotypes (RX1, RX2). Both were found in O. caespitosa, O. eriocarpa, O. mixotriche and O. peschkovae, while RX1 was present in O. nitens and O. triphylla, RX2 in O. grandiflora. The absence of diagnostic species-specific variants for the markers studied, together with the sharing of cpDNA haplotypes and nrDNA ribotypes between species, and the resulting polytomies on the phylogenetic trees, confirm the hypothesis on the hybrid origin of some of them. Obviously, the reproductive barriers within the sect. Xerobia are weak. However, morphological differences between the species of the sect. Xerobia are clearly pronounced, even when they grow in sympatry.

遗传多样性和进化关系棘子草，O.玉兰，O. eriocarpa，O. mixotriche，O.鲷，O. peschkovae和O. triphylla，部分Xerobia亚属棘豆属植物的主要形态中心之一，猫头基于psbA–trnH，trnL–trnF和trnS–trnG的序列分析，研究了（贝加尔山脉的西伯利亚和蒙古东北部邻近地区）cpDNA和ITS nrDNA的基因间隔子。大多数种群的特征是叶绿体遗传多样性高（h从0.327到1.000，π从0.0001到0.0090），这是由于某些物种起源远古，而另一些物种则具有杂交和多倍性。共鉴定出67种单倍型，其中6种为单倍型。物种之间的亲缘关系不能令人满意地解决。只有三叶O.的单倍型形成了具有较高支持率的基团。也许，O.子草，O.玉兰，O. mixotriche和O.鲷构成单一的遗传复合体。关于ITS nrDNA多态性，我们仅检测到两种核糖型（RX1，RX2）。无论是在发现O.子草，O. eriocarpa，O. mixotriche和O. peschkovae，而RX1存在于O.鲷和O. triphylla，RX2在O.玉兰。缺乏针对所研究标记的诊断物种特异性变体，以及物种之间共有cpDNA单倍型和nrDNA核糖型，以及在系统树上产生的多态性，证实了其中一些杂种起源的假说。显然，该教派内部的生殖障碍。干燥很弱。但是，该教派之间的形态差异。Xerobia明确宣布，即使他们在同域发展。