East Asian endemic seed-plant genera revisited: Fossils and biogeographic assembly

East Asia harbors exceptional genus-level endemism, but present distributions alone cannot distinguish regional diversification from survival following range contraction. Fossil evidence is critical to evaluating these histories, yet published records require taxonomic and stratigraphic reassessment. We compiled a revised inventory of 810 endemic and East Asian-centered seed-plant genera and updated their fossil record by incorporating additional occurrences, re-evaluating identifications and assigning explicit confidence grades. The synthesis retained fossil evidence for 72 genera. Fossils outside modern ranges document broader past distributions followed by contraction, whereas records within East Asia establish past regional presence. We integrated this evidence with stem-age estimates and ancestral-area reconstructions. Among 706 genera with stem-age estimates, the median stem age was 13.2 Ma, and 67.7% of estimates were Miocene or younger, indicating a predominantly Neogene signal alongside a smaller deep-time component. East Asia (29.5%), Indo-Malay (22.4%) and Tethys (21.3%) were the largest reconstructed ancestral-area categories, suggesting contributions from multiple source pools. Lineage divergence, diagnostic fossil occurrence, arrival in East Asia from other regions and range restriction represent distinct historical events. Together, the evidence supports a temporally and geographically composite history of East Asian endemism involving persistence, biotic exchange, regional extinction and diversification.