112 PLANT GEOGRAPHY 



Where the winds have been deprived of their moisture 

 by the mountains of Venezuela and Guiana, and the 

 Serra do Mar in South-eastern Brazil, we get the 

 savannahs known as " llanos " in Venezuela and as 

 " campos " in Brazil. Here we have a marked alterna- 

 tion of wet and dry periods. Trees are few, but for a 

 few Acacias, Anonas, and Cacti. The barrel-like " Bar- 

 rigudos " (Cavanillesia arbor ea Schum.) represent the 

 nearly related Baobabs of Africa; and on light soil 

 the savannah passes, as in Bahia and Ceara, into the 

 thorny Caatinga. South-westward almost pure groups 

 of Araucaria brasiliana A. Rich, occur, and forests of 

 " algarob," or Mimosece, extend into Paraguay. 



ANDINE REGION. On the well-watered eastern slope 

 of the Andes, or Montana Region, Hevea, with Carlu- 

 dovica, Melastomacece, and Palms extend to altitudes of 

 over 3000 feet, when the Cinchonas begin ; and then the 

 treeless but grassy Eastern Sierra or Puna extends from 

 10,000 feet to the snow-line, with numerous Cacti, dwarfed 

 Composites, spinous Colletia, and urticating Loasacece. 

 The Western Sierra of Peru is even more barren, passing, 

 through many degrees of latitude from the southern 

 border of Ecuador, into absolute desert. 



CHAPTER III 



THE SOUTHERN ZONE 



WIDELY separated for a considerable period, speaking 

 geologically, the land-masses of the South Temperate 

 Zone may each be considered as a cul-de-sac in which 

 southward extension has been checked. Among the 

 few links common to all we may mention the order 

 Proteacece and the coniferous genera Callitris and 

 Podocarpus. 



SOUTH AFRICA. Extending eastward and to the south 

 of the Orange River from the Kalahari Region, the 

 South African Region occupies a series of great plateaux 

 or Karroos and steep slopes. The extraordinary variety 

 of the vegetation is largely the result of the irregular 

 distribution of the rainfall. There are no large or dense 

 forests, no climbers, nor are trees or shrubs luxuriant. 



