Nature Plants, Published online: 11 April 2024; doi:10.1038/s41477-024-01671-6

BZR/BES transcription factors are widely recognized as mediators of brassinosteroid (BR)-responsive gene expression in seed plants, but details of how they act in species that lack BR perception are unclear. A study now uncovers an ancient mission of a BZR/BES transcription factor in sexual organ development in the liverwort Marchantia polymorpha.