The seed germination behaviour of six cold-temperate, cespitose Carex species occurring either in wet forests or wet, open habitats was investigated under different light and temperature conditions. Germination tests were conducted in the laboratory with cold and wet stratified seeds in light and darkness, under four constant-temperature regimes and one fluctuating regime. Other germination tests were carried out in an experimental garden where freshly matured seeds sown on the soil surface were exposed to conditions typical for a sun-exposed site and a shaded (forest) site for 2 years. In the garden experiments, seeds at the sun-exposed site germinated soon after sowing in three species, whereas late-shedding species or species exhibiting primary dormancy germinated the following spring. Under the dense leaf canopy at the forest site, germination was inhibited completely during the first season in all species. Wet-forest species (Carex elongata, Carex remota) germinated the following spring before the leaf canopy closed, whereas the sedges adapted to open habitats (Carex canescens, Carex cespitosa, Carex pseudocyperus, Carex paniculata) failed to germinate, or only a low percentage germinated. Following transfer of ungerminated seeds from the shaded site to the sun-exposed site in the summer of the second year of the investigation, almost all of the hitherto ungerminated seeds germinated within 10 days. Results of laboratory experiments supported the findings in the garden experiments. At low mean temperatures (7 and 10 °C) in light, sedges adapted to open habitats did not germinate at all or showed a low percentage of germination, whereas forest sedges showed good germination. A high diurnal temperature amplitude and (or) a high constant temperature was needed to trigger the germination of a fraction of the seeds in dark treatments. It is suggested that the forest sedges are adapted to using a brief temporal regeneration niche during mid-spring, when mean temperatures are close to 10 °C and the leaf canopy has yet to close in central European, wet deciduous forests. In contrast, sedges adapted to open habitats probably fail to germinate under forest conditions because of their higher temperature requirements. Key words: Carex, germination, light, temperature, dormancy.