New research reveals that cacti are among the fastest-evolving plant groups on Earth, driven by rapid changes in flower shape rather than size or pollinators. The findings from the University of Reading challenge long-held ideas about speciation dating back to Darwin. Scientists analyzed data from more than 750 species to reach their conclusions.
Researchers at the University of Reading examined flower length data across hundreds of cactus species. They found sizes ranging from 2 millimeters to 37 centimeters, yet this variation had little impact on the rate of new species formation. Instead, the speed at which flowers changed shape emerged as the key driver of diversification over both recent and ancient evolutionary periods.