NO. 2229. FOSSIL PLANTS FROM BOLIVIA— BERRY. 113 



significant than similar tables ordinarily constructed by paleo- 

 botanists for like purposes. Thus of the 82 species of plants recorded 

 from Potosi, after deducting the 16 indefinite forms referred to form 

 genera such as Antholithus, Carpolithus, Poacites, Phragmitcs, Pal- 

 mophyllum, Pecopteris, Rubiacites, Cypselites, and LeguminositeSj 54 

 of the Potosi species out of the 66 remaining are so similar to living 

 forms that in a majority of cases it would have done but little violence 

 to the facts to have identified them as fossil occurrences of these 

 existing forms. Without elaboration then it may be stated that the 

 fossil flora is preponderantly modem in its aspect, and this similarity 

 to the existing flora of the American tropics is too great to warrant 

 considering the fossil flora as older than the late Tertiary. I know of 

 no described flora as young as even the late Miocene that is as homo- 

 genous and does not contain some exotic elements or some genera 

 that are not still found in the same general region. Summarizing, it 

 may be noted that the Potosi fossil flora contains no species not 

 closely related to still existing species, no genera not still found in 

 the same general region, several genera not otherwise known fossil, 

 and an abundant representation of relatively modern types and 

 localized genera, as for example those of the Papilionaceae. 



One has only to go eastward or northeastward a few hundred miles 

 from Potosi to find what is essentially the same flora as that found 

 fossil, existing, however, under climatic conditions quite different 

 from those prevailing at the present time at Potosi or upon the high 

 plateau of Bolivia. 



Categorical conclusions regarding the exact physical environment 

 of the fossil flora can not be deduced, but certain more general 

 statements are warranted. The number of fossil forms definitely 

 correlated with existing forms is 54. Forty-six of these fossil forms 

 are represented in the existing flora of the Amazon Basin, and many 

 of these extend greater or less distances into eastern Bolivia, such 

 details as are available being introduced under the systematic 

 description of the species. A number of these range northward to 

 Central America and the Antilles and some are more characteristic 

 of the •Orinoco or northwestern part of the Amazon Basin than of 

 that part in the latitude of Bolivia. In two or three cases where the 

 existing species closest to the fossil is confined to this more northerly 

 region, as in Polystichum and Myrica, these genera are represented 

 in the existing flora of Bolivia by other species of the genus, material 

 of which has not been available for comparison. 



In the whole fossil flora enumerated comprising a representation of 



85 species only the following can be regarded as Andean or West 



Coast forms: Festuca, Escallonia, Amicia, Polystichum, Porliera, 



Euphorbia, and Myrteola. This is a relatively small number and of 



3343— 19— Proc. N. M. vol.54 9 



