Taxonomic identity and typification of selected names of North American Potamogetonaceae

Most names in North American Potamogetonaceae have not been typified. Details of typifications are given for 72 names based on North American material published in the genus Potamogeton mainly by North American botanists. All names are reviewed for their nomenclatural validity and legitimacy, and interpreted taxonomically. Holotypes are indicated for 31 names and previously declared lectotypes or neotypes are listed for eight names. Lectotypes are designated for 24 previously untypified names and step-2 lectotypifications are proposed for three names that were based on heterogeneous material. Type material for three Rafinesque names and one proposed by Wood have not been located. An annotated list provides collection data, type status, homotypic synonyms, and currently accepted names. Two names are excluded from Potamogeton, being based on species of Myriophyllum (Haloragaceae).