Isoetes ×blondeaui hyb. nov. (Isoetaceae), a new hybrid quillwort from eastern Quebec, Canada

The hybrid between diploid Isoetes echinospora and tetraploid I. laurentiana is reported from six sites along the St. Lawrence River near Quebec City. Morphological characteristics and distinguishing features are identified, and the binomial I. ×blondeaui, hyb. nov. is proposed. All occurrences are in biogeographically significant freshwater tidal marsh habitat. The hybrid is expected to occur in small numbers within most large I. laurentiana populations.