Germination response to temperature and flooding of four Central European species of Bolboschoenus

Germination of four Central European Bolboschoenus species (B. yagara, B. koshewnikowii, B. maritimus and B. laticarpus) was studied. The need for stratification and the influence of temperature and water regime on seed germination were tested in the laboratory. Cold wet stratification in the laboratory as well aswater stratification in the field enhanced the germination of all species. Germination was facilitated by increasing stratification length, but differed between species. Field stratification in water improved the germination of all species compared to stratification in soil. Germination requirements of the four Bolboschoenus species, despite the broader ecological amplitude of B. laticarpus, were similar. The best germination occurred after four months of field stratification in cold water. All species germinated best in aerobic conditions when the day/night temperature fluctuations were high (30/10 °C). These conditions correspond to those occurring where the seedlings tend to establish themselves in the field: exposed pond bottoms or wet soil in field depressions.