Cocconeis pediculus Ehrenberg and C. placentula Ehrenberg var. placentula (Bacillariophyta): Typification and taxonomy

Abstract

The nominate varieties of the monoraphid diatoms Cocconeis pediculus EHRENBERG and C. placentula EHRENBERG are typified. Discrepancies from common concepts in Ehrenberg's types, habitats and descriptions were discovered which might affect our current understanding of both Cocconeis species. To ensure stabilization of names and concepts for these two taxa, epitypes from a location in Berlin close to the locus typicus are presented. Monoclonal cultures of these two taxa have been established. Morphological and morphometric data from clones as well as from populations for both taxa are presented. The taxonomy of C. pediculus and C. placentula var. placentula is discussed and evaluated in the context of historical and recent publications. © Czech Phycological Society.