Desmid of the month
August 2008

Xanthidium octocorne

In former times this species was accounted the genus Arthrodesmus ¹. The genus name Arthrodesmus Ralfs having appeared to be illegitimate ², nowadays our species under discussion usually is placed in the genus Xanthidium³. As some of the characteristics of that genus (such as an ornamented, median inflation of the semicell body) are wanting, for this and some allied species Compère ⁴ designated  a separate genus, Octacanthium. In practice, however, that latter genus name is but seldom used.

Xanthidium octocorne, named after its 8-angled cells, hardly can be confused with any other species. In the Netherlands it is rather common in oligo-mesotrophic moorland pools, less common in fen hollows. Zygospores are only incidentally encountered.