One of the results of our field work in northern Michigan during the summer of 1968 was extensive collecting in several limestone sinks located in northern Alpena County. Many interesting and rare ferns were reported from these sinks by Hagenah (1955). ... After several collecting trips to the sinkholes, we can add the moss Orthotrichum pallens as new to eastern North America and several noteworthy records of rare or infrequently collected hepatics.