567 



savannahs of Napo, Guaviare, Meta, and 

 Apure *. This arm crosses, between 7° and 

 3° of south latitude, the basin of the forests 

 of the Amazon, and the absence of trees on 

 so great an extent of territory (the prepon- 

 derance which the small monocotyledon 

 plants have acquired) is a phenomenon of the 

 geography of plants which belongs perhaps to 

 the action of ancient pelagic currents, or 

 other partial revolutions of our planet. 



£. Plains of the Rio de la Plata, and of Pata- 

 gonia, from the south-west slope of the groupe 

 of the mountains of Brazil, to the strait of 

 Magellan, from 20° to 53° of latitude. These 

 plains correspond with those of the Missis- 

 sipi and of Canada in the northern hemi- 

 sphere. If one of their extremities draws less 

 nigh the polar regions, the other enters so 

 much further into the region of palm trees. 



also the name of Pajonal (plain which produces straw), be- 

 tween the Rio Paro, a tributary stream of the Ucayali and 

 the banks of the Huallaga. 



* I have named the plains covered with gramma, in the 

 order in which they succeed each other from south to north, 

 from the 30° of south, to the 9° of north-latitude. The sa- 

 vannahs between the Rio Vermejo and the Pilcomayo, 

 (south lat. 22°-25|°) are called Llanos de Manso, after the 

 name of a Spaniard who made the first essays of cultivation 

 in those desert countries. (Brackenridge, Vol. 2, p. 17). 



