Chap. Ill] MOUNTAIN REGIONS IN THE TROPICS 



747 



The basal region is covered with continuous tropical rain-forest only in the south 

 (Chiapas) ; further north the rain-forest is confined to moist ravines (barrancas), whilst 

 xerophilous woodland formations, with Cactaceae, arborescent Liliaceae, thorny 

 Acaciae, prevail on the hot declivities (Figs. 443 and 445). From about 1,000 meters 



Fig. 444. Flora of the alpine savannah of Serra do Picu, Brazil. 1. Baccharis aphylla. 



upwards the rainy montane region commences with luxuriant rain-forest, in which 

 evergreen oaks are the dominant trees. Higher up, in accordance with the already 

 decided winter-cold of this latitude, the forest assumes the character of temperate 

 summer-forest ; by the end of winter the oaks are completely leafless. From 2,000 

 meters upwards conifers occur, and the highest belt of forest is a coniferous forest with 



