RHYTISMA AMERICANUM SP. NOV - A PREVIOUSLY UNDESCRIBED SPECIES OF RHYTISMA ON MAPLES (ACER SPP.)

Differences in developmental morphology, host range, and restriction f ragment length polymorphisms are consistent with the hypothesis that t he species of Rhytisma currently causing an epiphytotic on Norway mapl e (Acer platanoides) in the northeastern United States is not the same fungus that is endemic on red and silver maples in North America. The latter fungus, erroneously designated as R. acerinum for many years, is a different and previously undescribed species. We propose Rhytisma americanum.