p. 109 - 116 QUELQUES OBSERVATIONS CONCERNANT L'ECOLOGIE DE L'ESPECE DESMOTRICHUM UNDULATUM (J.AG.) REINKE (PHAEOPHYTA) AU LITTORAL ROUMAIN Hilarius Vidor Skolka et Florian Vasiliu Institute Roumain de Recherches Marines Constanta Abstract The occuring and developping along the Black Sea shores of Desmotrichum undulatum (J.Ag.) Reinke, one of the brown seaweeds, is described in this paper. Some of the ecological patterns (substrate, hydrodynamics, light, temperature and salinity), as well as pollutant agents that are implied in Desmotrichum undulatum biology are described. The great biomasses produced in April-May on the rocky shores by this alga, had a high significance.