Invisible in plain sight: recurrent double allopolyploidy in the African Sphagnum ×planifolium (Sphagnaceae)

Abstract Microsatellites, nucleotide sequences, and flow cytometry were used to determine if two sympatricAfrican peat mosses (Sphagnum ×planifolium and S. ×slooveri) had a history of inter-subgeneric hybridization and to assess their phylogenetic relationship. Both species had previously not been considered to be hybrids. Sphagnum ×slooveri was found to be gametophytically allodiploid. Its maternal parent was S. recurvum (or a closely related species) of subg. Cuspidata and its paternal parent was an unidentified species from the S. africanum complex of subg. Subsecunda. Sphagnum ×planifolium was found to be a cryptic species complex of gametophytic allotriploids, with recurrent double allopolyploidy resulting in at least two evolutionarily distinct lineages. The maternal parent of both lineages was S. ×slooveri. The paternal parent of one lineage (S. ×planifolium I) was an unidentified haploid associated with the S. capense complex of subgenus Subsecunda while the paternal parent of the second lineage (...