Merostachys is a Neotropical woody bamboo genus that occurs in the understory and along forest borders. Our taxonomic studies of its species and morphological analyses have allowed us to recognize morphological groups in the genus. Previous molecular analyses, which included relatively few species, supported Merostachys as monophyletic and sister to Actinocladum or Athroostachys. We here provide a phylogenetic estimation for Merostachys based on a broader taxon sampling and seven plastid markers (one coding: ndhF 3′ end; four intergenic spacers: rps16-trnQ, trnC-rpoB, trnD-trnT and trnT-trnL; and two introns: rpl16 and rps16). We aimed to test the monophyly of the genus, to verify its relationship with other genera of Arthrostylidiinae, mainly Athroostachys and Actinocladum, and to test whether the previously identified morphological groups were congruent with the molecular data. The monophyly of the genus was confirmed, as was its sister relationship with Athroostachys, although alternate hypothesis testing could not reject a sister relationship with Actinocladum. Two well-supported clades in Merostachys were recovered, one of which encompasses a polytomy. These clades did not exhibit consistent morphological synapomorphies and were not congruent with the morphological groups; however, floret surface (shiny vs. dull) was correlated with the two clades. The lack of resolution in Merostachys, as exemplified by the polytomy, can be attributed mainly to incomplete lineage sorting, suggesting a recent radiation in this group.

中文翻译：

---

基于多位点质体序列的Merostachys进化枝（禾本科：Bambusoideae：Bambuseae：Arthrostylidiinae）的形态演变和分子系统发育

Merostachys是新热带木本竹属，发生在林下和森林边界。我们对其种类的分类学研究和形态分析使我们能够识别属中的形态群。以前的分子分析（包括相对较少的物种）支持Merostachys作为单系和Actinocladum或Athroostachys的姐妹。在这里，我们提供了一个系统发育估计Merostachys基于更广泛的类群取样和七个质标记（一个编码：ndhF 3'末端;四个区：rps16-trnQ，北塞浦路斯土耳其共和国-的rpoB，TRND-TRNT和TRNT-trnL; 和两个内含子：rpl16和rps16）。我们的目的是测试该属的一字性，以验证其与节肢动物科的其他属（主要是炭疽菌和放线菌属）的关系，并测试先前确定的形态学组是否与分子数据一致。尽管与假单胞菌的另一种假设检验不能排斥与放线菌属的姊妹关系，但该属的单亲性得到了确认，其与炭疽菌的姊妹关系也得到了证实。Merostachys中的两个支撑良好的进化枝进行了手术切除，其中之一是多发性切除。这些进化枝没有表现出一致的形态同形，并且与形态学组不完全一致。然而，小花表面（光泽与暗淡）与两个进化枝相关。如多角体切除术所例示的，Merostachys缺乏分辨力，主要可归因于血统谱系排序不完全，这表明该组患者近期有放疗。