168 BERRY— LOWER EOCENE FLORA OF [April 25, 



shores of the extended Mediterranean sea of the Pliocene and to 

 have subsequently been entirely exterminated in that region by the 

 glaciation of the Pleistocene, while surviving in both North America 

 and Asia by reason of the prevailing north and south trend of the 

 of the mountain ranges. Some of the other genera of the Magnoli- 

 ace?e are represented by scattered fossil species but the record is too 

 incomplete for generalizations. A survey of all the facts leads me 

 to consider America as probably the original home of Magnolia and 

 despite the massing of the existing forms in the eastern United States 

 and their extension to Arctica in the Eocene, they probably originated 

 in a warm-temperate or subtropical latitude, spread northward 

 across Arctica to Eurasia, were cosmopolitan in the Tertiary, becom- 

 ing restricted to the southeastern parts of Asia and North America 

 by the aridity accompanying uplift, so well illustrated in the Eocene 

 and later history of the Rocky Mountain and Great Plains province, 

 and were finally killed off in Europe by the Pleistocene glaciation. 



Lesquereux referred two forms from the Wilcox of northern 

 Mississippi to Magnolia but these both prove to be species of Ter- 

 minal ia as Lesquereux had surmised in his preliminary studies. The 

 genus Magnolia is, however, represented in the Wilcox by two large- 

 leafed species, both of which are common to the basal Eocene of the 

 Rocky Mountain Province. Neither show any close affinity with the 

 antecedent Upper Cretaceous forms which are so common in the 

 embayment area of Alabama and northeastward along the Atlantic 

 Coastal Plain. 



The family Anonacess contains about 700 existing species dis- 

 tributed among about 48 genera, only two of which are present in 

 North America. The family is practically confined to the tropics, a 

 single Australian species and the North American genus Asimina with 

 6 or 7 species being the only conspicuously extratropical forms. The 

 area of maximum representation is southeastern Asia and the adjoin- 

 ing region of Malaysia, for while only 16 genera are confined to this 

 region it contains over 350 species, and six additional genera (.1/7/- 

 iusa, Uvaria, Polyalthia, Oxymitra, Mclodorum, and Poporvia) with 

 a total of over 250 species have the bulk of their species in this area. 

 Only a single genus is confined to Australia and the bulk of the Aus- 



