Staurodesmus mucronatus

The genus Staurodesmus was established by Teiling (1948) by fusing parts of the genera Arthrodesmus and Staurastrum. Species of Staurodesmus are marked by smooth-walled semicells which in apical view are bi- to pluriradiate, and furnished with one single spine per radius. S. mucronatus belongs to a group of species which usually are triradiate (formerly alotted the genus Staurastrum)*.  In frontal view, S. mucronatus is characterized by  ellipsoid semicells bearing  a rather short, horizontal or slightly upwards projected spine at each of the poles. In the Netherlands it is a rather rare species, occurring in benthos of slightly acidic, mesotrophic water bodies.

* For an example of a biradiate Staurodesmus species, see our desmid of the month of February 2003.

Reference

Teiling, E., 1948. Staurodesmus, genus novum. — Botaniska Notiser 1948: 49-83.