TROPICAL NATURE 



can be put to uses which, if ordinary wood were used, would 

 require hours or even days of labour. There is also a regu- 

 larity and a finish about it which is found in hardly any other 

 woody plant; and its smooth and symmetrically ringed 

 surface gives an appearance of fitness and beauty to its 

 varied applications. On the whole, we may perhaps consider 

 it as the greatest boon which nature gives to the natives of 

 the eastern tropics. 



Mangroves 



Among the forms of plants which are sure to attract 

 attention in the tropics are the mangroves, which grow 

 between tide-marks on coasts and estuaries. These are low 

 trees with widely-spreading branches and a network of aerial 

 roots a few feet above the ground ; but their most remarkable 

 peculiarity is, that their fruits germinate on the tree, sending 

 out roots and branches before falling into the muddy soil 

 a completely formed plant. In some cases the root reaches 

 the ground before the seed above falls off. These trees 

 greatly aid the formation of new land, as the mass of aerial 

 roots which arch out from the stem to a considerable distance 

 collects mud and floating refuse, and so raises and consoli- 

 dates the shore ; while the young plants, often dropping from 

 the farthest extremity of the branches, rapidly extend the 

 domain of vegetation to the farthest possible limits. The 

 branches, too, send down slender roots like those of the 

 banyan, and become independent trees. Thus a complete 

 woody labyrinth is formed ; and the network of tough roots 

 and stems resists the action of the tides, and enables the 

 mud brought down by great tropical rivers to be converted 

 into solid land far more rapidly than it could be without 

 this aid. 



Sensitive Plants 



Among the more humble forms of vegetation that attract 

 the traveller's notice none are more interesting than the 

 sensitive species of Mimosa. These are almost all natives of 

 South America, but one species, Mimosa pudica, has spread 

 to Africa and Asia, so that sensitive plants now abound as 

 wayside weeds in many parts both of the eastern and west- 

 ern tropics, sometimes completely carpeting the ground with 



