154 BERRY— LOWER EOCENE FLORA OF [April 25, 



France. In the systematic chapter detailed comparisons are made 

 between the Wilcox and the foreign species, which show a striking 

 parallelism. 



The Urticales includes the families Ulmaceae, Moraceae and Urti- 

 caceae together containing about 1,600 existing species. The Urti- 

 caceae are largely herbaceous forms and the Ulmaceae are mostly 

 extratropical. 



The Ulmaceae comprise thirteen genera and about 140 existing 

 species, widely distributed in temperate and tropical regions. A 

 single species of Planer a described originally by Newberry from the 

 Western Eocene is doubtfully identified from the Wilcox. The 

 genus is monotypic in the existing flora and confined to wet swampy 

 situations in the warm temperate region of southeastern North Amer- 

 ica. Its geologic history goes back to the Upper Cretaceous at which 

 time species have been recognized along the Atlantic coast from 

 North Carolina northward. Thus there is no reason why it should 

 not have been present in the early Tertiary of the embayment unless 

 it be argued that the climate was too warm. 



The Moraceae, by far the largest family of the order Urticales 

 and the only one certainly represented in the Wilcox flora, contains 

 between 900 and 1,000 existing species segregated among about 55 

 genera, of which the genus Ficus is by far the largest, including 

 about 60 per cent, of the existing species of the family. The Mora- 

 ceae are distinctly tropical and warm temperate types and are most 

 abundant in the oriental tropics, although the dominant genus Ficus 

 is widespread and the family is also largely represented in the South 

 American tropics. 



There are at least 18 monotypic genera of which one is North 

 American, four South American, four African, and nine Australian. 

 No single tribe is confined to a single continental area and all show 

 apparent anomalies of distribution due to our lack of knowledge of 

 their geologic history. The genera Ficus, .Irtocarpus and Artocar- 

 pidium go back to the base of the Upper Cretaceous and numerous 

 additional genera appear in the Eocene. 



There are 23 species of Moraceae in the Wilcox flora. The genus 

 Arto carpus is represented by three well-marked species. In the ex- 

 isting flora the two score known species of Artocarpus are confined 



