Polytrichum commune var. uliginosum

Polytrichum commune var. uliginosumWallr.

Hyväksytty nimi,

Hodgetts et al. 2020: 182 Polytrichum commune var. uliginosum Wallr. was raised to specific rank by Schriebl (1991) following his observation of stability in the described diagnosticfeatures in culture. Hill et al. (2006) accepted this view, supported partially by Bijlsma et al. (2000), who found two distinct genetic entities within Polytrichum commune s.lat. that they recognised as Polytrichum uliginosum and Polytrichum commune, with Polytrichum commune var. perigoniale (Michx.)Hampe treated under Polytrichum commune. Subsequent molecular and herbarium studies (Bell et al. 2010; Kariyawasam et al. in prep), have confirmed that these two genetic entities exist, although they show that Polytrichum uliginosum should be treated under Polytrichum commune while Polytrichum perigoniale Michx. is the correct name for the other entity. This is because Bijlsma et al. (2000) based their sampling of Polytrichum commune on Schriebl’s concept of the species, with specimens corresponding to Polytrichum commune var. perigoniale (as can be seen in their Figure 1C), while the concept of Polytrichum uliginosum they used presumably included plants corresponding morphologically to Polytrichum commune var.commune. The type of Polytrichum commune in the Hedwig-Schwägrichen-herbarium comprises nine stems on a single herbarium sheet. Some of these appear to have been added by Schwägrichen for comparison purposes and are assignable to Polytrichum juniperinum, Polytrichum appressum (=Polytrichumsubpilosum) and Polytrichum perigoniale. Six others match Hedwig’s original description of Polytrichum commune and descriptions in the literature he cited, as well as the concept of Polytrichum commune var. commune traditionally used in Europe. Of these, one will be selected as a lectotype for Polytrichum commune (Kariyawasam, in prep).