TERTIARY FLORA OF CHILE 103 



Paraguay. The genus Allamanda with about a dozen species 

 ranges from Central America to Brazil. The genus Hsema- 

 dictyon, or Prestonia to give it Robert Brown's name, has 

 between 30 and 40 climbing species in the country between 

 Mexico and Rio de Janeiro. The form referred to Apo- 

 cynophyllum is compared with existing Brazilian species 

 of Tabernamontana, a large modern genus found in both 

 tropics. Apocynophyllum is a form-genus for members of 

 this family whose generic affinity is not certainly established, 

 and consequently a large number of fossil species are known. 



The order Polemoniales is represented by a form referred 

 to Cordia of the family Boraginaceae and by species of Tecoma 

 and Bignonia of the family Bignoniacese. Although the 

 material is scanty in the case of the first of these I see no 

 reason for questioning these determinations. Cordia is a 

 large genus of shrubs or trees with upward of 250 existing 

 species in the warmer regions of both hemispheres, more 

 than half being American. It is present in the Upper Creta- 

 ceous and earlier Tertiary of southeastern North America, 

 but is sparingly represented in the known geological record. 

 It is still present in the montana and elsewhere in eastern 

 Bolivia. 



Tecoma has 80 existing species in the region between New 

 Jersey and Argentina, most of which are found in the trop- 

 ical portion of this area. The genus is scarcely known fossil. 

 The Chilean species is close to the wide ranging Tecoma 

 stans Jussieu, which is abundant in eastern Bolivia. Tecoma 

 is abundant in the lower valleys of the western Andes in 

 central Peru and is thus one of the few genera of the Chilean 

 flora that still persists west of the Cordillera, at least in the 

 region south of Ecuador. 



This, however, is without other meaning than that the 

 peculiar climate from Tumbez southward to Coquimbo 

 resulting from the uplift of the Andes has made this coastal 

 strip uninhabitable for the normal flora of those latitudes. 



