🌅 Cacti Are Evolving Surprisingly Fast

Sunrise Stat
May 28, 2026

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Researchers at the University of Reading in the U.K. compared the flower length of 774 cactus species representing nearly all major cactus subfamilies, finding the emergence of new cactus species isn’t driven by flower size or specialized pollinators, but by how quickly cactus flowers change shape over time. Despite having flowers that span a 185-fold size range (from .08 inches to 1.5 inches), the study found no connection between flower length and how quickly new cactus species emerge. Instead, the researchers uncovered a consistent pattern across both ancient and modern evolutionary history between cactus species whose flowers changed most rapidly and the emergence of new species.

For more than a century, scientists have viewed flowers specialized for particular pollinators or environments as the major drivers of evolution and plant diversity. The present study challenges that view and provides valuable insights into why some branches of the tree of life burst into thousands of species, while others remain small.

The idea that specialized flower structures are the main drivers of plant evolution comes from Charles Darwin’s famed work with orchids, which led him to propose that specialized flower shapes and colors attract pollinators and drive plant diversification. Darwin’s work with orchids was a foundational moment in evolutionary science and forever changed our understanding of plant pollination and the coevolution of species.