20i BERRY— LOWER EOCENE FLORA OF [April 25, 



Miocene species in Prussia, Baden, Switzerland, Bohemia and Croa- 

 tia. A well-marked species occurs in the Claiborne (Lutetian) 

 ranging along the Claiborne coast from northeastern Georgia to 

 central Louisiana. 



It is impossible from the known facts to discuss the place of ori- 

 gin of the family, but it is obvious that certain genera were evolved 

 toward the close of the Lower Cretaceous in equatorial America and 

 have inhabited that or adjacent areas throughout the long stretch of 

 time down to the present. 



The order Rhamnales includes about 1,000 existing species of 

 shrubs, trees and vines about equally divided between the families 

 Rhamnacens and Yitaceae. It closely parallels the Sapindales in its 

 floral development but is distinguished by the mostly tetracyclic flow- 

 ers with opposite stamens and often lacking a corolla. The leaves 

 are simple and typically alternate. Of the two families only the 

 Rhanmacere is represented in the Wilcox flora. 



The family Rhamnacese (Frangulaceae) includes 47 genera and 

 about 500 species of shrubs and trees mostly of the tropics but with 

 several genera extending for considerable distances into the temper- 

 ate zone, the genus Rhamuits in particular being mostly extratropical 

 in the northern hemisphere. The genera Zizyphus } Adelia and Gon- 

 dii ia are found in all tropical countries. Almost half of the genera 

 are common to more than one continental area. America has the 

 greatest number of peculiar genera (15) with about 85 species. Two 

 monotypic genera are confined to Asia, five genera including the 

 large genus Phylica Linne together With about 70 species are con- 

 fined to Africa and five genera including the two large genera Spy- 

 ridium Fenzl. and Cryptandra Smith in all with about 70 species are 

 confined to Australia. 



Ten or eleven genera, of which five are present in the Wilcox 

 flora, are found fossil, the three largest being Rliainiuis. 1'aliitriis 

 and Zizyphus. The genus Rhamnus Linne which L cosmopolitan 

 in the northern warm temperate and subtropical zones has about 

 •ity existing species. There are considerably over one hundred 

 fossil species, mostly well characterized with simple often entire 

 leaves with ascending secondaries and closely spaced tine percurrent 



