Ecological and evolutionary drivers of inflorescence diversity in Chinese angiosperms

Abstract Inflorescences are the key reproductive structures of angiosperms. Although the biogeography of inflorescences has been explored in large‐scale studies, there remains a lack of research on the trade‐offs in fitness among inflorescence types, as well as the spatial patterns of inflorescence morphology and their ecological and evolutionary drivers. Based on the inflorescence types of 25,778 Chinese angiosperm species and incorporating their distribution data, this study presents an integrated analysis of the effects of environmental variables, phylogenetic relationships and potential pollinator assemblages to systematically investigate the spatial patterns of inflorescence diversity and their ecological and evolutionary determinants. We observed a hump‐shaped pattern of inflorescence diversity along the first principal component axis (PC1), which was primarily associated with hydrothermal conditions. The peak diversity occurred in regions with moderate temperatures and precipitation, reflecting the trade‐offs among various inflorescence types. Indeterminate inflorescences predominantly occurred in regions with extreme environmental conditions (e.g. cold and arid climates), with northwestern China representing a major area of incidence. Phylogenetic analyses suggest that fluctuations in global mean surface temperature since the Cretaceous have promoted evolutionary transitions from determinate to indeterminate inflorescences, facilitating the adaptive evolution of indeterminate inflorescences in climatically unstable regions such as northwestern China. Additionally, the origin and rapid diversification of pollinating insects have enabled determinate inflorescences showing stronger co‐occurrence patterns with pollinators to persist in the climatically stable southeastern region of China. Moderate environmental heterogeneity and resource availability create conditions for the coexistence of both inflorescence strategies, thereby enhancing diversity in areas with intermediate hydrothermal conditions. Synthesis . These findings demonstrate that environmental factors have shaped the diversity of inflorescences both through direct constraints and indirectly via evolutionary history and interactions with potential pollinators. This study offers a novel perspective on the formation of inflorescence diversity by exploring the adaptive trade‐offs between two types under the influence of ecological and evolutionary factors.