The arrangement of floral primordia on the inflorescence has been examined in Triglochin maritima. Different inflorescences have spiral or multijugate forms of phyllotaxis. The inflorescence apex does not seem to give rise directly to a terminal flower, though floral primordia may ultimately arise on or very near the summit of the meristem. In the latter case a residual apex is left. These observations are combined with previous scattered data on the inflorescences of Triglochin. It is concluded that Triglochin inflorescences have a number of characters which are more usually associated with flowers.