Desmid of the month
October 2010
Sphaerozosma filiforme
Sphaerozosma is a filamentous desmid genus with Cosmarium-like cells characterized by a pair of rod-like, apical processes disposed obliquely in such a way that one of them may overlap the frontal side of the adjacent cell, the other one the back side. Contrary to Sphaerozosma vertebratum (desmid of May 2007) in Sphaerozosma filiforme* the two apical processes are rather far apart. Often, the filaments of cells are strongly twisted. Sph. filiforme is characteristic of slightly acidic, mesotrophic pools. In the Netherlands nowadays it is very rare. Only recently it was found again after a period of more than 60 years.
* also known as Onychonema filiforme.
Image © Koos Meesters
Cell filament of Sphaerozosma filiforme. Notice the interconnecting rod-like processes. Between the apical processes of given cells a thin transverse thread is to be seen representing the boundery-line of mucous cushions produced by the adjacent cells.
Cell dimensions (L x B, exclusive of processes): 12-14 x 13-15 µm.
