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.



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 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.

Another specimen of Sphaerozosma filiforme, showing twisting of the filament

SEM picture of some cells of Sphaerozosma filiforme showing transversal rows of cell wall pores (two per semicell).

SEM picture of Sphaerozosma filiforme. Notice apical processes being inserted far apart (with in between a string of mucilaginous material).