Desmid of the month - October 2008

Docidium baculum

Cell of Docidium baculum (sampled in the Czech Republic), marked by slender, cylindric semicells somewhat constricted above the swollen basis. Cell dimensions (L x B): 290 x 13 µm

Detail of the cell isthmus. Notice the longitudinal plications at the basis of the semicells.

The genus Docidium (see also D. undulatum) resembles the much bigger and commoner genus Pleurotaenium. The essential difference is , in Docidium, the occurrence of a whorl of short, longitudinal cell wall plications on either side of the isthmus (lacking in Pleurotaenium). The genus Docidium numbers but a few species. The most widely distributed species is D. baculum. In the Netherlands it has been encountered in some oligo-mesotrophic moorland pools, but only in the beginning of the last century. Recent observations are wanting.

Docidium baculum, SEM imageSEM image © Jan Šťastný

SEM- image of Docidium baculum.