3 8 4 



ZONES AND REGIONS 



[Pt. Ill, Sect. I 



deviations from the climatic type as regards both the nature of the flora 

 and its oecology. Swampy ground is frequently occupied by pure woods 

 of certain species of palms. Thus, in Trinidad, I observed Mauritia 

 setigera forming the sole vegetation in swampy parts of the savannah 

 of Aripo ; in Venezuela and Brazil, other species of Mauritia (M. vinifera, 

 M. flexuosa) similarly congregate to form pure woods ; Phoenix paludosa 

 grows socially in the swamps of the Ganges delta, and so on. Certainly 

 mixed forests are not wanting on swampy ground, but they are usually 

 much less rich in species, in particular as regards large trees, than those of 

 less wet soil. The best known among them are the mangroves of the 



Fig. 20S. Swamp-forest in Borneo. From a photograph by Kukenthal. 



tropical shores within reach of tides ; they owe their peculiarities partly 

 to the saline nature of the substratum, and will be dealt with later on in 

 connexion with other littoral formations. In contrast with mangrove, the 

 mixed forest of fresh-water swamps in the interior of Burma, Sumatra, 

 and Borneo (Fig. 208), has hitherto been very little studied, although 

 it seems to afford much that is characteristic as regards both flora and 

 oecology. 



Kurz states 1 that swamp-forest is 'the most curious forest in Burma, and of 

 great interest to the botanist. In fact, its constituent plants are so dissimilar to 



1 Kurz, op. cit., p. 29. 



