NO. 2 



GENTRY : LAND PLANTS 



193 



As a whole the Pacific tierra caliente may be considered as one major 

 floristic unit, so uniform are its climatic and vegetative characters. But 

 while the strand flora is homogeneous, that of the coastal interior is not, 

 for several floristic elements have met and blended through the more 

 northern latitudes. Among these floral elements are Caribbean, the Mexi- 

 can Continental, and the Sinaloan. The latter two appear to have been 

 derived largely from a Tertiary element part of which during geologic 

 times may have migrated southward and blended with the more tropical 

 one. The following genera of trees and shrubs are common through the 

 Pacific tierra caliente from Sinaloa to Panama and are either abundant 

 in number of species or in individuals, exercise a dominating influence 

 in the vegetation, and are characteristic of the Pacific slope flora. The 

 legumes are the most dominating family of plants. 



Anacardium 



Solanum 



Coccoloba 



Cereus 



Eupatorium 



Hamelia 



Ruellia 



Ipomoea 



Diospyros 



Palms 



Piper 



Bursera 



Cordia 



The Costa Rican Pacific tierra caliente has apparently had little 

 botanical exploration. Men have preferred to visit the more varied and 

 interesting, as well as the healthier, highland. ''Certainly it is the least 

 agreeable in which to work, for the climate is hot, the forests and thick- 

 ets particularly so, and full of tangled vines and spiny branches, not to 

 mention the ticks that thrive better than elsewhere. On this account, 

 and for lack of good means of transportation, partly also because of the 

 sparsely settled country, the Pacific tierra caliente has been relatively 

 little investigated by botanists. Its exploration involves long rides on 

 horseback on obscure trails, where there are few and often uncomfortable 

 lodging places. It must not be forgotten that some localities on the Pa- 

 cific coast are noted for a virulent type of malaria" (Standley 1. c. p. 21 ). 

 The following enumerations of the Allan Hancock Pacific collections, 



Prosopis 



Pithecolobium 



Acacia 



Mimosa 



Lonchocarpus 



Enterlobium 



Cassia 



Diphysa 



Gliricidia 



Inga 



Caesalpinia 



Bauhinia 



Platymiscium 



Spondias 



Cedrela 



Ficus 



Ceiba 



Euphorbia 



Croton 



Jatropha 



Acalypha 



Hura 



Chlorophora 



Guasuma 



Psidium 



Byrsonima 



Cochlospermum 



Tabebula 



