Haplolepideous moss systematics has been through major changes based on morpho-molecular studies. However, many taxa remain little studied with still unclear circumscriptions and relationships among the traditionally recognized families. We inferred the phylogenetic relationships of the haplolepideous mosses based on a sample of 37 out of the 38 haplolepideous moss families and using mitochondrial (nad5 G1 intron) and chloroplast (trnS-rps4 spacer/rps4 gene and trnL gene/trnL-trnF spacer) markers. The resolved relationships indicate the need for rearrangements in the circumscription of the Aongstroemiaceae and Dicranellaceae and their genera, which correspond to the variation of morphological characters of leaf shape, rhizoid tuber morphology, and capsule and peristome traits. The two families, although historically considered morphologically close, were resolved as separate lineages in the core haplolepideous clade. The genera Aongstroemia and Dicranella were resolved as polyphyletic across the clades corresponding to the families Aongstroemiaceae and Dicranellaceae and other clades. The characterization of Aongstroemia by julaceous plants is not supported; the three species sampled here belong in three separate families and differ from one another in other (more stable) characters, such as the presence and shape of peristome teeth. Regarding Dicranella, the sampling of 13 of its 167 species suggests the broad morphological variation comprised by the genus under its current circumscription might be narrowed down to smaller ranges corresponding to the phylogenetically separate clades. The present molecular data furthermore suggest changes in the composition of the protohaplolepideous Dicranidae grade, including one Dicranella clade, a new lineage with a ditrichoid morphology, but excluding the Chrysoblastellaceae, which were resolved in the core haplolepideous clade. The latter finding implies the independent evolution of the rare double-opposite peristome type in both the protohaplolepideous grade and the core haplolepideous clade. Keywords haplolepideous mosses; nad5 G1 intron; polyphyly; phylogenetics; trnS-trnF Supporting Information may be found online in the Supporting Information section at the end of the article.

Molecular phylogenetic reconstructions of Rhabdoweisiaceae based on plastid (trnS-rps4 and trnL-F) and mitochondrial (nad5) DNA sequences and a comprehensive taxon sampling were performed, including 15 out of 16 genera currently attributed to the family, taxa recently found belonging to Rhabdoweisiaceae and expanded outgroups from related families of Dicranidae. The suggested revised delimitation of the family comprises Camptodontium (previously referred to Dicranaceae), three subaquatic species currently classified in Blindia (Seligeriaceae), and Glyphomitrium (previously referred to Ptychomitriaceae, Erpodiaceae or its own family) and Eucamptodon perichaetialis (the type species of the genus, previously referred to Dicnemonaceae). The emended delimitation of Rhabdoweisiaceae thus adds to the already high morphological heterogeneity resulting from the divergent evolution of specialized traits in different lineages of epiphytes and saxicolous hygrophytes. Taxonomic inferences from the phylogenetic analyses include segregation of three new genera, Pseudoblindia (for species currently recognized as Kiaeria falcata, Blindia robusta, B. lewinskyae and B. inundata), Ripariella (for Kiaeria riparia) and Brideliella (for Oncophorus wahlenbergii, O. demetrii and Symblepharis lindigii). Hollia is reinstated for the dicnemonoid Australasian species previously classified in Eucamptodon. Additionally, we propose to merge (1) Oreoweisia, Pocsiella and Pseudohyophila with Cynodontium, and (2) Kiaeria s.s. with Arctoa. Furthermore, we propose to limit Oncophorus to O. virens and O. integerrimus and expand the circumscription of Symblepharis to accommodate O. crispifolius, O. dendrophilus, O. elongatus and O. raui. The generic status and inclusion in Rhabdoweisiaceae are confirmed for Cnestrum and the recently described Notocynodontium, and the exclusion of Amphidium, Dichodontium, Holodontium and Hymenoloma from the family is supported.

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