Rhytidanthera is the only genus of Ochnaceae with compound leaves, and it forms sparse, small populations restricted to the primary forest of the Colombian and Venezuelan Andes and the sandstone hills of La Macarena and Chiribiquete. It has been suggested to be related to Godoya, Cespedesia and Krukoviella in taxonomic and phylogenetic studies. However, the relationships in this group remain poorly resolved, due to the lack of a wider molecular and taxonomic sampling. We present a phylogenetic study of tribe Sauvagesieae including three Rhytidanthera spp. and one species each of Godoya and Cespedesia, using sequences from one nuclear (ITS) and four plastid DNA regions (matK, ndhF, rbcL and trnL-F), in order to clarify the relationships among these four genera. We recover a new and well-supported phylogenetic hypothesis, with Rhytidanthera as sister to a clade comprising Godoya and the clade formed by Cespedesia and Krukoviella. This Neotropical clade was recovered as sister to the monotypic and African genus Fleurydora. The clade comprising Rhytidanthera, Godoya, Cespedesia and Krukoviella is supported by the presence of glandular structures (colleters) at the base of stipules and bracts. The colleters also evolved at the base of the sepals in this clade, with a secondary loss in Cespedesia and Krukoviella. We suggest that the combination of unequal-sized sepals enclosing the floral bud and the presence of colleters in members of this clade could have a role in the protection of leaves and flowers in the early stages of development, instead of acting in pollinator attraction.

中文翻译：

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Rhytidanthera（Ochnaceae）属不常见且分布狭窄的属的系统发育位置和腺结构的演变

Rhytidanthera是of科的唯一属，具有复叶，并且形成稀疏的小种群，仅局限于哥伦比亚和委内瑞拉安第斯山脉的原始森林以及La Macarena和Chiribiquete的砂岩丘陵。在分类学和系统发育研究中，它被认为与Godoya，Cespedesia和Krukoviella有关。但是，由于缺乏更广泛的分子和生物分类学样本，该组中的关系仍然难以解决。我们目前对包括三个Rhytidanthera spp的Sauvagesieae部落进行系统发育研究。和一个物种，分别是Godoya和Cespedesia，使用来自一个核（ITS）和四个质体DNA区域的序列（matK，ndhF，rbcL和trnL-F），以阐明这四个属之间的关系。我们恢复了一个新的且得到充分支持的系统发育假说，其中Rhytidanthera是包含Godoya以及Cespedesia和Krukoviella形成的进化枝的进化枝的姐妹。这种新热带进化枝是作为单型和非洲属Fleurydora的姐妹而被发现的。包括Rhytidanthera，Godoya，Cespedesia和Krukoviella的进化枝托叶和片基部有腺结构（（突）支持。筒夹还在此进化枝的萼片底部进化，在切斯佩德西亚（Cespedesia）和克鲁科维耶拉（Krukoviella）中发生了继发性损失。我们建议，包围花芽的不等大小的萼片和该进化枝成员中存在的筒夹的结合可能在发育的早期阶段对叶和花的保护中起作用，而不是充当传粉媒介的吸引力。