Abstract
Summary The palaeoecologic significance of post-Palaeozoic green calcareous algae is evaluated with what is known of the environments of comparable living algae. Here requirements and tolerances of temperature, bottomsediment, salinity and water-energy may be observed; depth is apparently significant only as it influences these. In the extinct algae, only a minority show clear taxonomic relationship to living algae, in palaeo-environmentsdeduced from independent evidence. Codiaceae and Dasycladales seem to have had environmental preferences like their living descendants, with preferredmicroenvironments in some genera.