Sramkó Gábor, Molnár V Attila, Tóth János Pál, Laczkó Levente, Kalinka Anna, Horváth Orsolya, Skuza Lidia, Lukács Balázs András, Popiela Agnieszka
Department of Botany, University of Debrecen, Debrecen, Hungary; MTA-DE "Lendület" Evolutionary Phylogenomics Research Group, Debrecen, Hungary.
MTA-DE "Lendület" Behaviourial Ecology Research Group, University of Debrecen , Debrecen , Hungary.
PeerJ. 2016 Dec 21;4:e2800. doi: 10.7717/peerj.2800. eCollection 2016.
The genus contains 25 species, all of which are small, herbaceous annuals distributed in ephemeral waters on both hemispheres. However, due to a high degree of morphological variability (as a consequence of their amphibious life-style), the taxonomy of this genus remains controversial. Thus, to fill this gap in knowledge, we present a detailed molecular phylogenetic study of this genus based on nuclear (rITS) and plastid (, , ) sequences using 27 samples from 13 species. On the basis of this phylogenetic analysis, we provide a solid phylogenetic background for the modern taxonomy of the European members of the genus. Traditionally accepted sections of this tree (i.e., and ) were found to be monophyletic; only -found to be a basal member of the genus-has to be excluded from the latter lineage to achieve monophyly. A number of taxonomic conclusions can also be drawn: , a high-ploid species, is most likely a stabilised hybrid between the main sections; merits full species status based on both molecular and morphological evidence; is a more widespread and genetically diverse species with two main lineages; and the presence of the Asian in the European flora is questionable. The main lineages recovered in this analysis are also supported by a number of synapomorphic morphological characters as well as uniform chromosome counts. Based on all the evidence presented here, two new subsections within are described: subsection consisting of the temperate species of the section, and subsection including the Mediterranean species of the section.
该属包含25个物种，均为小型一年生草本植物，分布于南北半球的季节性水域。然而，由于高度的形态变异性（因其两栖生活方式所致），该属的分类学仍存在争议。因此，为填补这一知识空白，我们基于核基因（rITS）和质体基因（……）序列，对该属进行了详细的分子系统发育研究，使用了来自13个物种的27个样本。基于这一系统发育分析，我们为该属欧洲成员的现代分类学提供了坚实的系统发育背景。该属传统上认可的组（即……和……）被发现是单系的；只有……被发现是该属的基部成员……必须从后一个谱系中排除以实现单系性。还可以得出一些分类学结论：……，一个高倍体物种，很可能是主要组之间稳定的杂交种；……基于分子和形态学证据都应给予完整的物种地位；……是一个分布更广且遗传多样性更高的物种，有两个主要谱系；并且亚洲的……在欧洲植物区系中的存在值得怀疑。在这一分析中恢复的主要谱系也得到了一些共衍征形态特征以及一致的染色体计数的支持。基于此处提供的所有证据，描述了该属内的两个新亚组：由该组温带物种组成的……亚组，以及包括该组地中海物种的……亚组。
