Desmid of the month
June 2005
Micrasterias rotata
M. rotata may be confused with some other Micrasterias species, in particular M. thomasiana (desmid of September 2002) and M. fimbriata (desmid of July 2003). From M. thomasiana it differs in the shape of the apical median incision (relatively narrow and clear-cut in M. thomasiana, gradually widening in M. rotata), from M. fimbriata in the shape of the highest-order lobules (spinous-denticulate in M. fimbriata, emarginate in M. rotata).
Although
M. rotata holds as one of the commoner Micrasterias species,
in the Netherlands its
distribution is seriously curtailed due to deterioration of the natural
habitat. Today M. rotata is only occasionally encountered in mesotrophic
moorland pools, peat pits and fen hollows.
Cell of Micrasterias rotata. Note the gradual widening of the median incision of the apical lobe and the emarginate lobules at the cell margin.
Cell dimensions (L x B): ca 280 x 250 µm
