Fire plays a major role in shaping ecosystems, but the evolutionary origins of its significant impact on current biomes remain unclear. Australia is one of the most fire-prone continents, with most of its landmass occupied by fire-dependent sclerophyll and savanna biomes. Unlike other continents with similar climates, Australia's flora is dominated by a single genus, Eucalyptus, and related Myrtaceae. A unique mechanism in Myrtaceae allows these plants to survive and recover from fire damage, contributing to their dominance. This study finds a conserved phylogenetic relationship between post-fire resprouting (epicormic) anatomy and biome evolution, dating back to 60-62 million years ago in the earliest Palaeogene. This suggests that fire-dependent communities existed 50 million years earlier than previously thought. The study predicts that eucalypt forests and woodlands could serve as excellent long-term carbon sinks compared to similar fire regimes in other continents. Fire maintains open communities by preventing the closure of forests. In Australia, fire has marginalized rainforests to a small portion of the continent and eliminated them from much of the suitable landscape. Fire-dependent communities in Australia are dominated by Myrtaceae, with 1,600 species, including 800 eucalypts. Many of these species are excellent post-fire epicormic resprouters, capable of regenerating from stems and branches after high-intensity fires. In eucalypts, epicormic buds are protected by thick bark, allowing them to sprout even after intense fires. This unique anatomy is different from other plant families. The study hypothesizes that the evolution of fire tolerance in Myrtaceae is directly linked to the origins and expansion of fire-dependent biomes in Australia, particularly the southern sclerophyll and northern savanna biomes. However, the influence of wildfires on the evolution of Australian biomes during the Palaeogene, when Australia was part of East Gondwana, has been little studied. The Australian fossil record provides limited direct evidence of fire before the mid-Miocene. The study shows that specialized epicormic resprouting originated in the eucalypt lineage at least 60 million years ago. A significant link was found between the evolution of this unique anatomy and the timing of shifts into the flammable sclerophyll biome. However, there was no statistical association with more recent shifts into the monsoonal biome. The study found that both epicormic resprouting in Myrtaceae and flammable sclerophyll biomes likely originated in the earliest Cenozoic, 60-62 million years ago. The distinctive epicormic resprouting anatomy in eucalypts has been strictly conserved until the present, despite changes in habitat and fire response. The study also suggests that fire-dominated communities were present in Australia during theFire plays a major role in shaping ecosystems, but the evolutionary origins of its significant impact on current biomes remain unclear. Australia is one of the most fire-prone continents, with most of its landmass occupied by fire-dependent sclerophyll and savanna biomes. Unlike other continents with similar climates, Australia's flora is dominated by a single genus, Eucalyptus, and related Myrtaceae. A unique mechanism in Myrtaceae allows these plants to survive and recover from fire damage, contributing to their dominance. This study finds a conserved phylogenetic relationship between post-fire resprouting (epicormic) anatomy and biome evolution, dating back to 60-62 million years ago in the earliest Palaeogene. This suggests that fire-dependent communities existed 50 million years earlier than previously thought. The study predicts that eucalypt forests and woodlands could serve as excellent long-term carbon sinks compared to similar fire regimes in other continents. Fire maintains open communities by preventing the closure of forests. In Australia, fire has marginalized rainforests to a small portion of the continent and eliminated them from much of the suitable landscape. Fire-dependent communities in Australia are dominated by Myrtaceae, with 1,600 species, including 800 eucalypts. Many of these species are excellent post-fire epicormic resprouters, capable of regenerating from stems and branches after high-intensity fires. In eucalypts, epicormic buds are protected by thick bark, allowing them to sprout even after intense fires. This unique anatomy is different from other plant families. The study hypothesizes that the evolution of fire tolerance in Myrtaceae is directly linked to the origins and expansion of fire-dependent biomes in Australia, particularly the southern sclerophyll and northern savanna biomes. However, the influence of wildfires on the evolution of Australian biomes during the Palaeogene, when Australia was part of East Gondwana, has been little studied. The Australian fossil record provides limited direct evidence of fire before the mid-Miocene. The study shows that specialized epicormic resprouting originated in the eucalypt lineage at least 60 million years ago. A significant link was found between the evolution of this unique anatomy and the timing of shifts into the flammable sclerophyll biome. However, there was no statistical association with more recent shifts into the monsoonal biome. The study found that both epicormic resprouting in Myrtaceae and flammable sclerophyll biomes likely originated in the earliest Cenozoic, 60-62 million years ago. The distinctive epicormic resprouting anatomy in eucalypts has been strictly conserved until the present, despite changes in habitat and fire response. The study also suggests that fire-dominated communities were present in Australia during the