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Martín SR1*, Sancho KD1,2, Peguero Pina JJ1,2 and Gil PE3
1Department of Agricultural, Center for Agri-Food Research and Technology of Aragon (CITA), Spain
2Agrifood Institute of Aragon-IA2, CITA-University of Zaragoza, Spain
3Aula Dei Experimental Station, Higher Council for Scientific Research (EEAD‐CSIC), Spain
*Corresponding author:Martín Sánchez Rubén, Department of Agricultural, Forestry and Environment Systems, Aragon Agri-Food Research and Technology Center (CITA), Zaragoza, Spain
Submission: December 04, 2024;Published: January 02, 2025
ISSN : 2640-9275Volume5 Issue1
Axelrod proposed a hypothesis to explain the origin and evolution of the evergreen sclerophyllous flora in the Northern Hemisphere, suggesting an insitu differentiation of clades at low-mid latitudes during the Cenozoic. This hypothesis highlights a continuous belt of sclerophyllous vegetation that was fragmented over time due to tectonic movements and climatic changes, including cooling and drying. The genus Quercus exhibits numerous sclerophyllous species, which reach their highest diversity in the latitudes he identified. However, the evolutionary histories of the two subgenera within Quercus-the New World and Old-World clades-show distinct patterns. This review examines whether Axelrod’s hypothesis holds true for Quercus by synthesizing recent molecular phylogenies, fossil records, and biogeographic analyses. Findings reveal that while Old World oaks largely align with Axelrod’s hypothesis, the recent diversification of the tropical New-World oaks challenge the framework he proposed.