Etymology
The genus is named in honor of German botanistHistory
In 1880, Oskar von Kirchner, Kirchner described ''Staurogenia tetrapedia''. In 1897, Schröder described ''Tetrapedia emarginata''Schröder, B. (1897). Attheya, Rhizosolenia und andere Planktonorganismen im Teiche des botanischen Gartens zu Breslau. Ber. Deutsch. Bot. Ges. 15:367–74. In 1898, Otto Kuntze, Kuntze moved ''Staurogenia tetrapedia'' to the genus ''Crucigenia'', in the name ''Crucigenia tetrapedia''.Kuntze,O.(1898). Revisio generum plantarum. Pars III (3). pp.1-576. In 1900, Robert Hippolyte Chodat, Chodat described the genus ''Lemmermannia'' and used ''T. emarginata'' (now ''L. emarginata'') as the type of the new genus. In 1904, Lemmermann moved ''Crucigenia tetrapedia'' into ''Lemmermannia'' as ''Lemmermannia tetrapedia'', which was not widely recognized; the old name ''Crucigenia tetrapedia'' was kept in use. The genus ''Lemmermannia'' had been ignored for many years until 2013. In 2013, Bock et al. found a new clade of algae including ''Crucigenia tetrapedia'' and three others using molecular methods. Bock et al. (2013) decided that ''Crucigenia tetrapedia'' and ''Lemmermannia emarginata'' are the same organism. Since ''C. tetrapedia'' was described first (in 1880) and has priority, it is the species name that should be used. The type of ''Lemmermannia'' thus changed its name, from ''L. emarginata'' to ''L. tetrapedia'' (Kirchner) Lemmermann 1904. Three other species formerly in the genus ''Tetrastrum'' were added to ''Lemmermannia''.Morphology
''Lemmermannia'' includes triangular or oval green, Plankton, planktonic algae that mostly form tightly joined square coenobia of 4 cells, with or without small rectangular opening in the centre. ''L. komarekii'' make coenobia of up to 16 cells in the form of near-square synceonobia, where 4 tetrads join together. The cells have a single plastid, with or without a small pyrenoid. All species lack spines, and mostly have smooth cell walls, with or without convexity. A minority of ''L. punctata'' individuals, as well as old empty cells of the species, have granules on the outer cell walls.Metabolism
''Lemmermannia tetrapedia'' can use hypoxanthine and allantoin as the only nitrogen source for photosynthesis, which indicates that eukaryotic algae share similar purine degradation pathway to higher plants, animals, and fungi.Reproduction
''Lemmermannia'' perform asexual reproduction (autosporation by sporangium); sexual reproduction has not been observed. ''Lemmermannia'' species perform two types of reproduction: ''L. tetrapedia'' exhibits ''Crucigenia''-type of autosporation where the daughter coenobium rotates 45˚ relative to the cell wall of the mother coenobium; the other four species produce daughter coenobia in the same orientation as the mother coenobia. This demonstrates that in this taxon a ''Crucigenia''-type of autosporation should not be used as a generic character.Phylogeny
Molecular phylogenies based on the SSU rDNA and ITS rRNA genes show ''Lemmermannia'' to be a sister clade to ''Botryococcus'' in Trebouxiophyceae.Species
, AlgaeBase accepted five species: *''Lemmermannia emarginata'' (Schröder) Chodat *''Lemmermannia komarekii'' (Hindák) C.Bock & Krienitz *''Lemmermannia punctata'' (Schmidle) C.Bock & Krienitz *''Lemmermannia tetrapedia'' (Kirchner) Lemmermann *''Lemmermannia triangularis'' (Chodat) C.Bock & KrienitzHabitat
All species inhabit freshwater around the globe. ''L. tetrapedia'' has been reported highly susceptible to heavy metals in water.Monteiro, M. T., Oliveira, R., & Vale, C. (1995)References
{{Taxonbar, from=Q84490584 Trebouxiophyceae genera Trebouxiophyceae Enigmatic algae taxa