The discovery of Myriophyllum exalbescens Fernald (Haloragaceae) in Europe and the typification of M.spicatum L. And M.verticillatum L.

Myriophyllum exalbescens Fernald, hitherto regarded as a North American endemic, has been fund to occur widely as a native plant in northern Europe, where it has occasionally been distinguished as a subspecies or variety of M.spicatum L.under the epithet squamosum Linnacus original concept of M.spicalum appears to have included M.exalbescens (and also M. Alterniflorum DC.) but selection of Burser VII(1)79 at UPS as lectotvpe ensures the continued use of the epithet spicatum for the native Eurasian weed species to which it is customarily applied. .M.verlicillalum L., the name of a morphologically similar species, is also lectotypified in a way that preserves its current usage. Distinguishing features of M.exalbescens and M.spicatum are provided along with details of the synonymy and presently known distribution in Europe of M.exalbescens .