‘ we , - ‘ , o ( i ' m % 4 
Ry mo 23 y 4 : 
‘Say be cede “@ } 4 a“ ‘ , ; / 
: y 
ae : 2 A s . is ‘ i] - 
- increases with the elevation of the ground ; and JZelozo- 
_ ¢actus takes the place of the columnar forms. Both sections 
possess thickets and forests, but composed of different 
trees. The almost unmixed groups of Araucarta brasiliensis 
are peculiar to the southern savannahs. To the west the 
savannahs extend as faras the affluents of the Paraguay and 
_ Madeira. Here, as on the coast, we come again to prime- 
val forests, the ‘ pantanals,’ of a tropical luxuriance, which, 
like the forests of Hyleea, owe their peculiarities to running 
_ water. ‘To the south of these the plains of Gran-Chaco, and 
-_ the woody highland of Paraguay, alternating with open grass- 
plains, almost entirely fill up the space between the Andes 
and the southern table-land of Brazil. Here are found the 
forests of ‘algarob,’ belonging to the Mimosez, and a 
Brazilian wax-palm, Cofernicia cerifera. 
20. The Tropical Andean Region. 
Throughout almost the whole of this region, like the ve é 
- last, there is a natural distinction between a chain of moun- 
tains rising almost immediately from the shore of the Pacific, 
forming a kind of littoral cordilleras, and an eastern series. 
“ef peaks which slope down to the broad lowlands of South 
America. In Peru and Bolivia the western chain includes 
an extensive highland, the Sierra or Puna district ; while on ~ 
the southern tropic both the ridge and the peaks disappear, 
and give place to the desert of Atakama. The Pacific 
coast of this entire region is an altogether rainless country, 
which is only watered in winter by slight mists, the ‘ garuas ;’ 
the Antarctic current of Humboldt which skirts the coasts 
bringing constantly fresh quantities of cold water, and 
_ causing the condensation of the aqueous vapour brought by 
the sea-winds. Drought prevails therefore not only on the 
_ land, but also on the sea, as is shown by the guano-deposits 
of the Chincha Islands. Only on the shores of the short 
rivers, or by means of artificial irrigation, can cultivation be 
Botanical Geography. cert 453 
