Abstract
We report here seven interesting taxa of Euastrum from the periphytic material of three macrophyte species (Cabomba haynesii, Eichhornia azurea, and Utricularia foliosa) occurring in the Chapada Diamantina, Bahia State, Brazil. Of those Euastrum taxa, E. westenii is new to science; E. bidentatum var. scottii, E. elegans var. prescottii, and E. informe var. oculatum were raised to the varietal level; E. ansatum var. concavum, E. ciastonii, and E. sibiricum had their geographic distributions enlarged to northeastern Brazil. Taxonomic notes and ecological information are provided for all taxa.