The genus Cecropia contains 61 species of high ecological importance in the Neotropics. Cecropia pachystachya Trécul has a wide geographic distribution and high morphological variability. The last taxonomic review of C. pachystachya was performed in 2005 and incorporated seven other Cecropia species by synonymization. However, this synonymization was not fully accepted by experts in Urticaceae because of high morphological variations in the taxon. In this study, we aimed to evaluate whether the morphological variations observed in C. pachystachya morphotypes also occurred at the DNA level and to contribute to the understanding of the evolutionary relationship between species morphotypes. Morphological analysis of eight species descriptors in 28 accessions of C. pachystachya allowed the differentiation of all five morphotypes evaluated. The analysis of the trnL-trnF (plastid) and ITS (nuclear) regions from 24 accessions by maximum parsimony, maximum likelihood, and Bayesian inference methods showed a robust molecular differentiation between C. pachystachya morphotypes. Climate was the main factor that seemed to influence clade formation in the phylogenetic trees. The higher genetic relation among morphotypes from the Amazon, Caatinga, and Cerrado regions corroborated previous hypotheses of close relationships between these biomes in past ages. The morphotype group from the Atlantic Forest seemed to be related to the proposed Pleistocene refuges to this biome. The overall analysis of morphological and molecular data shows robust differences between C. pachystachya synonymized morphotypes, which indicates the need of a taxonomic revision of the C. pachystachya complex and subsequent reinstatement of at least four synonymized species.

Cecropia属在新热带地区包含61种具有重要生态意义的物种。Cecropia pachystachyaTrécul具有广泛的地理分布和较高的形态变异性。最后分类审核C. pachystachya在2005年进行并纳入其他七个天蚕由synonymization种。但是，由于分类单元中形态上的高度差异，因此该别名未被荨麻科的专家完全接受。在这项研究中，我们旨在评估是否在C. pachystachya中观察到形态变化形态型也出现在DNA水平上，有助于理解物种形态型之间的进化关系。形态分析分析了28个种C. pachystachya中的八个物种描述子，可以区分所评估的所有五个形态类型。通过最大简约，最大似然和贝叶斯推断方法对24个种质的trnL-trnF（质体）和ITS（核）区域的分析显示，厚壁梭菌之间存在强大的分子分化形态型。气候是影响系统进化树进化枝形成的主要因素。来自亚马逊地区，卡廷加地区和塞拉多地区的形态型之间较高的遗传关系，证实了以往这些生物群落之间密切关系的假说。来自大西洋森林的形态型群似乎与该生物群系的拟更新世避难所有关。形态学和分子数据的整体分析显示，帕氏隐孢子虫同义形态型之间存在明显差异，这表明需要对帕氏隐孢子虫复合体进行分类学修订，并随后至少恢复四个同义物种。