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. 2016 Apr 21;4:e1897. doi: 10.7717/peerj.1897

Figure 6. Tectonic activity during the Eocene.

Figure 6

Tectonic activity during the Eocene and past and modern distribution of the New World (white) and Old World (yellow) groups within Quercus. Black lines indicate major subduction zones, red lines major orogenies. Note that the high latitude lineage of oaks (Quercus Group Lobatae, Group Quercus, Group Protobalanus) evolved in tectonically stable regions, whereas the low latitude lineage (Quercus Group Ilex, Group Cyclobalanopsis, Group Cerris) evolved in tectonically unstable regions. Uppercase and lowercase letters refer to extant and extinct distribution areas of major oak lineages: P,p, Group Protobalanus; Q,q, Group Quercus; L,l, Group Lobatae; I,i, Group Ilex; C,c, Group Cerris; Y,y, Group Cyclobalanopsis. Palaeotopographic map base used with permission from Ron Blakey, © Colorado Plateau Geosystems.