Phylogeny of digitaria sections Trichachne and Trichophorae (Poaceae, Panicoideae, Paniceae): a morphological and molecular analysis. New circumscription and synopsis

The present study provides evidence for taxonomic delimitation of Digitaria sect. Trichachne based on morphological data (micro- and macromorphology) and molecular data. A phylogenetic analysis was performed using 121 morphological characters and ITS sequences of 22 species and one variety of Digitaria plus three outgroups. In all topologies (based on morphological, molecular, and combined data) Digitaria sect. Trichophorae was non-monophyletic and nested within D. sect. Trichachne. Digitaria sect. Trichophorae is thus synonymized under D. sect. Trichachne and the circumscription of D. sect. Trichachne is emended. Diagnostic morphological characters related to spikelet structure are described and documented with SEM. A key to taxa belonging to D. sect. Trichachne is provided, as well as a synopsis including synonymy, iconography, geographical distribution, and ecology. The neotype of Trichachne sacchariflora Nees is herein designated. Complete illustrations of Digitaria eggersii, D. hit...本研究基于形态学数据（显微及宏观形态学）与分子数据，为马唐属（Digitaria）类雀稗组（sect. Trichachne）的分类界定提供了实证依据。研究采用121个形态性状，对22种、1变种马唐属植物的内转录间隔区（ITS）序列及3个外类群开展系统发育分析。所有基于形态数据、分子数据及联合数据构建的拓扑结构均显示：马唐属截穗组（sect. Trichophorae）并非单系类群，且嵌套于类雀稗组之内。据此，截穗组被归并入类雀稗组，同时修订了类雀稗组的分类界定。本研究描述了与小穗结构相关的鉴别形态性状，并辅以扫描电子显微镜（SEM）图像进行佐证。文中提供了隶属于类雀稗组的类群检索表，以及包含同物异名、图解资料、地理分布与生态习性的分类概述。本研究同时指定了糖花类雀稗（Trichachne sacchariflora Nees）的新模式标本，并完整展示了埃格马唐（Digitaria eggersii）、D. hit……的插图。