Global biogeography and macroevolutionary patterns of angiosperm inflorescence types

The huge variety of inflorescences plays an important role in the reproductive success and diversification of flowering plants. However, the influence of climate on inflorescence diversity at macroecological and macroevolutionary scales remains poorly understood.

In this study, we map the global spatiotemporal pattern of inflorescence types and investigate the influence of climate on the spatiotemporal patterns of angiosperm inflorescence diversity.

Our results reveal a clear latitudinal trend in inflorescence types, with indeterminate inflorescence frequency increasing away from the equator. Pollination mode composition and temperature variables are strong correlates of the geographic variation in inflorescence-type frequency. We further reveal that lineages with determinate inflorescence have a significantly higher net diversification rate than those with indeterminate inflorescence. The frequency of evolutionary transitions from indeterminate to determinate inflorescences consistently decreased during the Cenozoic. Significantly, the evolutionary dynamics of inflorescence types during the Cenozoic show clear latitudinal differences: The proportion of indeterminate inflorescence at high latitudes increased with time and with the decline in paleotemperature, while that at middle-to-low latitudes decreased.

These results indicate strong climatic forcing on floral dynamics by influencing inflorescence types and their coevolution with animal pollination over large biogeographical and macroevolutionary scales.