METHODS

RADseq analyses were applied to a sample of 384 collections representing the European, North American, and (to a lesser extent) Asian ranges of the complex. The data were subjected to maximum likelihood phylogenetic analyses and analyses of genetic structure using the software, STRUCTURE, and multivariate ordination approaches.

RESULTS

Defined phylogenetically, the S. recurvum complex includes S. angustifolium , S. fallax , S. flexuosum , S. pacificum , and S. recurvum , as distinct clades with little evidence of admixture within them. In addition, we resolved another clade, sister to either S. pacificum or S. fallax , that is currently unnamed and is referred to in this paper as S. “pseudopacificum.” We confirm that S. balticum , a species not generally included in the S. recurvum complex, and S. obtusum , never associated with the complex by previous authors, are nested within it among the core species. Species with geographic ranges that span Europe, eastern North America, and Western North America exhibit a sister-group relationship between amphi-Atlantic and Pacific clades. European plants within S. flexuosum form a clade that is nested within a paraphyletic group of eastern North American plants; this species does not occur in western North America.

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. Please be aware that if you ask to have your user record removed, we will retain your name in the records concerning manuscripts for which you were an author, reviewer, or editor. In compliance with data protection regulations, you may request that we remove your personal registration details at any time. (Use the following URL: https://www.editorialmanager.com/ajb/login.asp?a=r). Please contact the publication office if you have any questions.

Zipped folder with 294 files of demultiplexed Illumina reads for Sphagnum samples included in the analyses.

Phylip format alignment of 6148 RADseq loci generated by ipyrad for the 294 Sphagnum samples.

Structure format file (one line per sample, haploid data) with one randomly selected SNP per locus generated by ipyrad for 280 ingroup (Recurvum complex) Sphagnum samples.