Abstract
Morphological variation of Himantidium pectinale (=Eunotia pectinalis) and Fragilaria pectinalis var. undulata (=Eunotia pectinalis var. undulata) were examined using type slides in BM. The lectotype of Fragilaria pectinalis var. undulata is designated using a slide BM67796 from Ralfs' collection in BM. Eunotia pectinalis var. undulata should be a synonym of Eunotia pectinalis var. pectinalis.