THE EQUATORIAL ZONE. 267 



" determine" the character of the vegetation. They are 

 sights which help us to create some faint notion of those 

 primeval forests where the overarching trees shut out the 

 sky and exclude the very beams of the sun, whilst they cast 

 a soft green light over the matted and interlaced vegetation 

 below. 



We are, however, not altogether strangers now to the 

 nature of tropical forests (Plate XY.), and do not forget that 

 the dense underwood with which they are choked up will 

 make it necessary to " hew out a path axe in hand ;" but 

 this is not so distinguishing a feature of the forests in the 

 Equatorial Zone as that dense tangle of climbing plants, 

 covered with leaves and flowers, which twine round each 

 other, and run from tree to tree in all directions, by hun- 

 dreds of different shoots. Having originally sprung from 

 the ground, they ascend the trees, adhering to them by 

 their under surface, till, the original root becoming ex- 

 hausted, or insufficient to supply these plants through all 

 their immense length, they afterwards forsake their parent 

 soil, and send down air-roots, which, as they hang sus- 

 pended in the hot, damp atmosphere of these forests (filled 

 as they often are with watery vapour), draw in the neces- 

 sary supply of nourishment. And in this way these climb- 



