Refs:
Süßwassertang: A Fern Disguised as a Liverwort
http://www.indefenseofplants.com/blog/2019/1/26/swassertang-a-fern-disguised-as-a-liverwort

Li et. al. 2009 Identifying a mysterious aquatic fern gametophyte
http://link.springer.com/article/10.1007%2Fs00606-009-0188-2