Observations on Rytiphloea tinctoria (Clem.) C. Ag. ball-forms in Stagnone waters (Western coast of Sicily). - Observations onRytiphloea tinctoriaball-form community in a coastal lagoon (Stagnone, Sicily) are reported. The discovery of « intermediate » benthopleustophyte forms (the attached form is absent in the lagoon) mirrors the different hydrodynamic conditions that are found in the area. No fructification of any sort was seen throughout the large number of specimens dredged. Comparative investigations between the ball and attached form shows a certain degree of variation in the « habitus », while the anatomical structure is similar. The ball-forms ofRytiphloea tinctoriacan be thought as an ecotype.