The yellow-green alga Pseudostaurastrum is a unicellular genus belonging to the phylum of Eustigmatophyta, formerly transferred from the Xanthophyta by Schnepf et. al. (1996). Recently, the phylogenetic position of Pseudostaurastrum was investigated using 18S rRNA gene sequences and it was confirmed ed that P. limneticum and P. enorme form a sister branch to other Eustigmatophyceans included in the study (Hegewald et. al., 2007; Přibyl et al., 2012).