Pellia

Pellia is a small but widespread genus of liverworts in the cool and temperate regions of the northern hemisphere. It is classified in order Pelliales and is a member of the family Pelliaceae within that order. Süsswassertang, a plant grown submerged in aquaria was once considered to be Pellia endiviifolia, but is now known to be the indeterminate gametophyte of a Lomariopsis species, a type of fern. Pellia liverworts are also often confused with Monosolenium tenerum, another liverwort....read more on Wikipedia.