THE NEOTROPICAL REGIONS 283 



plateau. The trees are low, and often thorny, and arc associated 

 with shrubs of many kinds. Many of both trees and shrubs cast 

 their leaves in the dry season. In the caatinga are found many 

 Cacti, Bromeliads, and other succulents, and there is a marked 

 development of bulbous plants, which are only evident in the 

 rainy season, when the trees renew their foliage, and many are 

 adorned with showy flowers. 



Southern Brazil has a remarkably large number of extremely 

 showy trees, shrubs and climbers, many of which adorn the gardens 

 of the warm temperate zone, like the Riviera, California and Aus- 

 tralia. The well known Bougainvilleas, Bignonias, and passion- 

 flowers, mostly come from this region, and the Jacaranda with its 

 delicate foliage and masses of beautiful blue flowers. 



The caatinga of Brazil may be compared to the bush-veldt of 

 the south African plateau. 



In the region of the Orinoco, according to Spruce, the caatinga 

 formation is mainly due to poor soils, and the trees are evergreen 

 with the profusion of epiphytic growths associated with a humid 

 atmosphere. 



The coastal mountains of Venezuela and the adjacent region of 

 Colombia show a large percentage of deciduous trees. As one sails 

 in sight of these coasts in the summer, the mountain slopes present 

 a very dreary picture due to the large number of bare deciduous 

 trees. This is a striking contrast to the rich evergreen vegetation 

 of the Guiana lowlands and Trinidad, and more resembles the 

 caatinga of the eastern Brazilian highlands. 



The tropical Amazonian forest ascends the eastern slopes of the 

 Andes to a height of 3,000-4,000 feet, above which there is a gradual 

 increase of temperate types and a corresponding disappearance of 

 the lowland species. 



The eastern slopes of the Andes, at the headwaters of the Ama- 

 zon have an extremely heavy precipitation, and the difficulties of 

 exploring these dense forests have been graphically described by 

 Spruce who spent several years in this region. Owing to their 

 inaccessibility, as well as the fevers and other drawbacks to ex- 

 ploration, these forests are still very imperfectly known. 



Except where the forests have been cleared there is little open 

 country at the lower elevations, although there are a few spots, 

 which owing to their topography, are relatively dry, and free from 



