Desmid of the month
August 2002

Euastrum germanicum

Eustrum germanicum is one of the species which formerly in the Netherlands was encountered only very incidentally but in the last decades seems to become decreasingly rare. Morphologically it is a characteristic species hardly or not to be overlooked. Having its closest affinity to a group of predominantly tropical species (Coesel 2000) it seems to take the Netherlands from the (south)eastern part of Europe (Coesel 1978). From Great Brittain, Euastrum germanicum is still unknown (West & West 1905, Brook & Williamson 1991). Interestingly enough, not only the number of Dutch find sites but also the density of the populations encountered is increasing. Whereas former reports referred to a few incidentally encountered cells, in 2000 mention was made of an abundant ocurrence in some newly excavated peat pits.

References:

• Brook, A.J. & D.B. Williamson, 1991. A checklist of desmids of the British Isles. - Freshwater Biological Association, occasional publication no. 28,40 pp.
  
  
• Coesel, P.F.M., 1978. Taxonomical, geographical and ecological notes on Euastrum mononcylum var. germanicum Schmidle (Chlorophyta, Desmidiaceae). - Arch. Protistenk. 120: 436-445.
  
  
• Coesel, P.F.M., 2000. Diversification of the Euastrum mononcylum group of desmids (Chlorophyta, Desmidiaceae). - Syst. Geogr. Pl. 70: 263-273.