Systematics of the cosmopolitan aquatic genus Elatine

The cosmopolitan genus Elatine (Elatinaceae) includes about 25 aquatic species of mostly diminutive aquatic plants, whose relationships have not been evaluated using a phylogenetic approach. The taxonomic study of this group has been complicated by the small stature of the plants, their minute reproductive structures, and their cosmopolitan distribution. Consequently, much uncertainty exists with respect to species delimitations, their geographical distributions, and interspecific relationships. To clarify the infrageneric classification of Elatine and to provide insights on interspecific relationships within the genus, we conducted a phylogenetic study of nearly all (24) of the currently recognized species using both morphological and molecular data. The tree topology obtained based on morphological data (including vegetative and reproductive characters) was less-resolved than the trees based on molecular data, derived from either nuclear (ITS) or two plastid regions (matK/trnK and rbc...

广布属沟繁缕属（Elatine，沟繁缕科Elatinaceae）包含约25种小型水生植物，目前尚未有基于系统发育方法的研究对其系统关系进行解析。该类群的分类学研究因植株体型微小、繁殖结构纤细以及广布的分布格局而复杂化。因此，在物种界定、地理分布以及种间关系方面仍存在诸多不确定性。为厘清沟繁缕属的属下分类，并为该属内的种间关系研究提供参考，我们基于形态学与分子数据，对当前已被认可的近全部（24种）沟繁缕属物种开展了系统发育研究。基于形态学数据（涵盖营养与繁殖性状）得到的拓扑结构分辨率，低于基于细胞核转录间隔区（ITS）或两个质体区域（matK/trnK与rbc……）的分子数据所构建的系统树。