ABSTRACT
Sea grasses are marine spermatophytes which occur in the families Potamogetonaceae and Hydrocharitaceae. In several species flowering has been studied under controlled conditions. In the Potamogetonaceae the species Syringodium filiforme Kutz, Syringodium isoetifolium Dandy, Cymodocea serrulata Aschers, et Magnus, Zostera capensis Setehell, and Zostera marina L. The flowers of the sea grasses within the Potamogetonaceae are very simple or actino-morphous, without a true perianth. In Zostera the flowers are arranged on one side of a flattened spadix enclosed in a spathe. The flowers occur on a short branch arising from a leaf axil. In Zostera marina the influence of light has been studied on the development of inflorescences. It appears that there is a highly synchronizing action of periodic light on the outgrowth of the female inflorescences, whereas the sensitivity of the male inflorescences seems to vary during the season.
