Geographic patterns (IMAGE) KeAi Communications Co., Ltd. Caption Geographic patterns of the mean genus age (a and b) and the standardized effect size of the mean genus age (c and d) for liverworts in North America. Panels a and c were based on genus presence or absence in each regional flora of liverworts and panels b and d were based on species richness per genus in each regional flora of liverworts. Credit QIAN ET AL. Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. No derivatives or adaptations of the work are permitted. License CC BY-NC-ND Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.