Leaf growth in the seagrass Syringodium filiforme Kütz

Field measurements made during the summer of 1982 in the Indian River lagoon, Florida, showed that Syringodium filiforme Kütz. displays a consistent pattern of growth. The cylindrical leaves lengthen at initial constant rates from a basal region, slow when approaching maturity, and finally cease growing. Elongation rates of individual blades varied by a factor of 3.6, from 0.86 to 3.11 cm day^?1, but were usually similar within a factor of 1.5 for leaves growing on the same shoot. Leaf diameter was primarily determined by growth in the basal meristem region and varied from 0.80 to 1.47 mm during growth of an average 40 cm blade. Syringodium also partitions growth among leaves in a consistent manner. On an upright shoot that bears 1–3 leaves, growth is almost totally confined to the youngest leaf with a new leaf starting as the previous leaf stops. For productivity studies of Syringodium, monitoring growth of the youngest leaves on several leaf shoots will give accurate estimates of mean growth rates.