Riccia atromarginata (Ricciaceae, Marchantiophyta) new to the Western Balkans, with notes on its morphology

This is the first record of the liverwort Riccia atromarginata for the Western Balkans. It was found on conglomerate terraces in the city of Podgorica, Montenegro, at the confluence of the rivers Ribnica and Morača. The material from Montenegro as well as living samples from Tenerife, Gran Canaria and Cyprus served as a basis for a detailed description of the main characteristics of the species, on the basis of which Riccia atromarginata can be reliably identified. However, for some characteristics there is a clear variability.