Graham and Jarzen (4), studying a deposit of 

 Oligocene age in western Puerto Rico, were able to iden- 

 tify to genus 44 out of 165 morphological types of fossil 

 pollen and spores, some not there now. These temperate 

 tree genera were listed: Engelhardia, Fagus, Liquidam- 

 bar, Nyssa, and Salix. These tropical American genera 

 there about 45 million years ago are absent now: Ber- 

 noullia, Bombax, Catostemma, Jacaranda, Pelliciera, 

 and Tetrorchidium. The first 3 are in Bombacaceae, 

 mentioned above as a family poorly represented. 



17 



^^H 



