An extensive reed bed on the north shore of the inner Tay Estuary is briefly described. Studies in the summers of 1975, 1976 and 1978 showed it to comprise monodominant stands of Phragmites communis Trin. The standing crop of shoots was sampled at the end of the season of vegetative growth and analysed by simple biometrical methods. Certain important spatial and architectural characteristics of the community varied in a regular manner with position in the bed. Estimates of the above ground productivity of intact stands ranged from 100 to 150 tonnes/ha in a poor growing season. Commercial harvesting operations, conducted since 1975, produced an immediate and consistent decrease in shoot stature, apparently followed by a slow increase in density and productivity. The behaviour of the downshore edge of the bed and the details of its annual development above and below ground require further study.