The dioicous, pleurocarpous moss, Pleurozium schreberi, is considered to fruit rarely in North America. In northern Michigan, a number of fruiting populations were sampled by random quadrats and field collections. Plants were scored for the presence of male or female gametangia and sporophytes. Frequencies of fruiting were related to the relative frequencies of male and female plants. Three factors appear to be responsible for the varying degrees of fruiting observed: the ratio of sexes within a bisexual population, segregation of the sexes into unisexual clumps, and the ratio of sterile to sexually differentiated plants within a population. Fragmentation of the light, fragile stems is suggested as a possible means of asexual reproduction in Pleurozium. Extensive vegetative propagation could lead to the establishment of large unisexual clumps. Development and maturation of perichaetial and perigonial inflorescences and sporophytes appear similar to those in Great Britain. Green, fresh antheridia empty of sperm, archegonia with swollen venters, sporophytes with newly elongating setae, and sporophytes of previous cycles with dehisced capsules were observed during July and August.