PREMISE The Sphagnum recurvum complex comprises a group of closely related peat mosses that are dominant components of many northern wetland ecosystems. Taxonomic hypotheses for the group range from interpreting the whole complex as one polymorphic species to distinguishing 6-10 species. The complex occurs throughout the Northern Hemisphere, and some of the putative species have intercontinental ranges. Our goals were to delimit the complex and assess its phylogenetic structure in relation to morphologically defined species and intercontinental geography. METHODS RADseq analyses were applied to a sample of 384 collections from Europe, North America, and Asia. The data were subjected to maximum likelihood phylogenetic analyses and analyses of genetic structure using the software STRUCTURE and multivariate ordination approaches. RESULTS The S. recurvum complex includes S. angustifolium, S. fallax, S. flexuosum, S. pacificum, and S. recurvum as clades with little evidence of admixture. We also resolved an unnamed clade that is referred to here as S. "pseudopacificum." We confirm that S. balticum and S. obtusum are nested within the complex. Species with bluntly acute to obtuse stem leaf apices are sister to those with acute to apiculate leaves. Most of the species exhibit some differentiation between intraspecific population systems disjunct on different continents. CONCLUSIONS We recognize seven species in the amended S. recurvum complex, including S. balticum and S. obtusum, in addition to the informal clade S. "pseudopacificum." Although we detected some geographically correlated phylogenetic structure within widespread morphospecies, our RADseq data support the interpretation that these species have intercontinental geographic ranges.

中文翻译：

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与分类学和地理相关的泥炭藓复合体（苔藓植物）的系统发育结构

前提 Sphagnum recurvum 复合体由一组密切相关的泥炭藓组成，它们是许多北部湿地生态系统的主要组成部分。该组的分类学假设范围从将整个复合体解释为一个多态性物种到区分 6-10 个物种。该复合体遍布整个北半球，一些假定的物种具有洲际范围。我们的目标是根据形态学定义的物种和洲际地理来界定复杂并评估其系统发育结构。方法 RADseq 分析应用于来自欧洲、北美和亚洲的 384 个集合的样本。使用软件 STRUCTURE 和多变量排序方法对数据进行最大似然系统发育分析和遗传结构分析。结果 S. recurvum 复合体包括 S. angustifolium、S. fallax、S. flexuosum、S. pacificum 和 S. recurvum 作为进化枝，几乎没有混合证据。我们还解析了一个未命名的进化枝，这里称为 S.“pseudopacificum”。我们确认 S. balticum 和 S. obtusum 嵌套在复合体中。具有钝尖至钝茎叶尖的物种与具有尖尖至细尖叶的物种是姐妹物种。大多数物种在不同大陆上分离的种内种群系统之间表现出一些差异。结论 除了非正式的分支 S.“pseudopacificum”之外，我们还识别出修正后的 S. recurvum 复合体中的七个物种，包括 S. balticum 和 S. obtusum。尽管我们在广泛的形态种中检测到了一些地理相关的系统发育结构，