This is an abbreviated version of an article which will be published in the issue of the Journal of the Hattori Botanical Laboratory conmemorating the late Dr. S. Hattori, on the origin and taxonomic status of Hypnum heseleri Ando & Higuchi. Two hypotheses are proposed: a) the species is a recent introduction via aerial long-distance dispersal, e.g. from Latin America, and b) the species is a recent mutant of Hypnum cupressiforme. The last hypothesis is considered as being the most likely one.