Biogeography of Oaks in the Arcto-Tertiary Province

Abstract

duoush d Numerous allied trees, shrubs, and herbs inhabit th conifer-hardwood forests of Horas Their close ancestors occupied middle and high | latitudes into the Middle Miocene (15-16 colder and drier climates NEW Antarctic d (13 m.y.a.), numerous paired Or allied species a n the disjunct segregate forests across Holarctica.duri e Tertiary.The rarity of Tertiary oaks linking Eurasia-North Ameri cor jj day) at the north; fully ries of all oak species occur below latitude 30-35°N and y si seven reach latitude 50°N.P Vo iie into 280 to 300 species was chiefly in response t spreading drier and colder climate iis commenced in e middle Eocene, to increasing topographic diversity in the later Cenozoic, and to fluctua nk Quaternary climate.At times of major climatic shifts or increased relief, oaks responded opportunisticalis, probably by quantum steps (punctuated equilibria) that account for the numerous seri most climates from perhumid montane tropical and temperate regions to the goaded a Hopes and in areas of very d