BOTANICAL REGIONS. 



Little attention has hitherto been paid to the various interesting botanical 

 regions of the Hawaiian Islands. The .different types of forests, even at the 

 same elevation and often in one district, are so marked that one could draw 

 imaginary lines separating these various types of forests with their peculiar 

 species. There seems hardly to be a transition type present. It is owing to 

 the various lava flows of all ages that such types of forests are at present in 

 existence, but nevertheless climatic conditions, such as wind, rainfall, etc., are 

 also responsible for these peculiarities. This, of course, applies more to the 

 Island of Hawaii, which is the largest and supposed to be the youngest of the 

 group. 



If we include the scanty strand vegetation, which consists mainly of a few 

 herbaceous plants and three or four species of trees, which are scattered, single 

 ones here and there on the beaches, we have six botanical regions, each of which 

 has again to be subdivided into sections, owing to topographical changes caused 

 by lava flows and climatic conditions. Many changes on lava flows are caused 

 by rain and exposure to wind, which disintegrates the lava quicker than in other 

 regions more sheltered, and so decides the plants most adaptable to these re- 

 gions, though this in turn depends again on the nature of the lava itself, whether 

 aa (rough) or pahoehoe (smooth) lava. 



The botanical regions are as follows: 



1. Strand vegetation. 



2. Lowland region. (This region merges into the lower forest region) . 



Section a, dry region. 

 Section b, wet region. 



3. Lower forest region. 



Section a, windward side. 

 Section b, leeward side. 



4. Middle forest region. 



Section a, dry region. 



Section b, semi-dry. 



Section c, wet region. 



Section d, kipukas, (small areas of lands with no trace of lava, soil 

 black and fertile in dry section, surrounded by 

 newer lava flows; richest in tree species). 



5. Bog region. 



6. Upper forest region. 



