Wikipedia
Süsswassertang
Süsswassertang ( German spelling: ; see ß) is a type of aquarium plant. It was long considered to be a liverwort, which it strongly resembles, but in 2009, a molecular phylogenetic study determined that it is, in fact, an fern gametophyte. Further, it is a species of Lomariopsis. It is closest to Lomariopsis lineata, but may be a new, unnamed species. Many reference sources on the web describe it as L. lineata, but its inclusion in that species has not been validly determined. Efforts to induce the plant to form a sporophyte have failed, which may indicate status as a new species. This plant was first mis- identified as Pellia endiviifolia before the analysis that determined its true status.