This paper deals with typification of three species names in Isoetes described from France: the lectotype previously designated for I. delalandei J.Lloyd is here superseded by another lectotype according to new evidence, and lectotypes are designated for I. echinospora Durieu and I. tenuissima Boreau. Selected specimens are preserved at ANG for I. delalandei, and at P for the two others. Scanning Electron Microscope (SEM) images of the spores, known to provide important routine characters in Isoetes, were acquired from the types, and information about the loci classici are provided. Isoetes echinospora and I. tenuissima have currently disappeared from their loci classici.