Saxicolous Bryophytes of an Ordovician Dolomite Escarpment in Interlake Manitoba, with New Species Records for the Province

Abstract

An assessment of bryophyte species growing on an Ordovician dolomite escarpment in the Interlake region of Manitoba known as Marble Ridge revealed a diverse flora composed mostly of circumboreal floristic elements. Two liverwort families (including three species) and four moss species are reported for Manitoba for the first time: the liverworts Athalamia hyalina (Sommert.) Hatt. (Cleveaceae), Mannia fragrans (Balbis) Frye et Clark (Aytoniaceae), and Mannia sibirica (K. Müll.) Frye et Clark (Aytoniaceae) and the mosses Brachythecium collinum (Schleich. ex C. Müll.) Schimp. in B.S.G., Grimmia teretinervis Limpr., Schistidium frigidum H. H. Blom, and Seligeria donniana (Sm.) C. Müll. An annotated summary of these and other bryophyte species documented at the site is provided. The diversity of encountered bryophytes can mostly be attributed to the moist and shaded microclimatic conditions on the escarpment and the large number of microhabitats the escarpment supports. This study represents one of few accounts of bryophytes in the region and highlights the importance of this particular geologic formation in supporting a number of species that are expected to be regionally uncommon.