Three distinct bark patterns of American beech (Fagus grandifolia Ehrh.) were exhibited by trees growing in naturally occurring forest stands in New Hampshire, U.S.A. Consistent differences in periderm anatomy were found to be associated with each particular bark pattern. Two patterns were typical of trees which maintained the first periderm in a superficial position. Another bark pattern is interpreted as being the result of normal rhytidome development, an uncommon occurrence in American beech.