Phylum: Charophyta   Family: Mesotaeniaceae

Netrium digitus var. rhomboideum Grönblad 1920

Ohtani (1990) gives the habitat in Japan for N. digitus taxa as entirely assiciated with Sphagnum. However, Brook & Williamson (2010) give a wider habitat preference. This variety differs in being spindle-shaped.

References: 
Ohtani, S. (1990) A Taxonomic Revision of the Genus Netrium (Zygnematales, Chlorophyceae).
Brook, A.J. & Williamson, D.B. (2010) A Monograph on some British Desmids.