TIERS OF VEGETATION IN TROPICAL FORESTS. 185 



forest, we must, however, never forget that it consists 

 not of one, but of several distinct tiers of vegetation, 

 rising one above the other. Just as a lofty building 

 has its different stories, so the forest has its different 

 gradations; beginning at the top with lofty trees of 

 gigantic growth, having beneath them a second, and 

 even a third forest, of smaller, shade-loving trees, of 

 various sizes, beneath which again are other under- 

 growths, consisting of ferns, and herbaceous plants of 

 different kinds, often extending in a matted covert down 

 to the very ground itself. Mr. Wallace, in his charming 

 and instructive work upon Tropical Nature, furnishes 

 us with the following graphic description of one of these 

 forest landscapes: 



" The observer new to the scene is first struck by the 

 varied, yet symmetrical trunks, which rise up with perfect 

 straightness, to a great height, without a branch, and which, 

 being placed at a considerable distance apart, give an im- 

 pression similar to that produced by the columns of some 

 enormous building. Overhead, at a height of perhaps a hun- 

 dred feet, is an almost unbroken canopy of foliage." "Usu- 

 ally so dense, that but an indistinct glimmer of the sky is 

 to be seen." " There is a weird gloom, and a solemn silence, 

 which combine to produce a sense of the vast, the primeval, 

 almost of the infinite. It is a world in which man seems 

 an intruder." * 



Dr. Schweinfurth, the well-known German traveller in 

 Central Africa, speaks to the same effect, as regards 

 these giant trees in the forests of the Southern Niam- 

 Niam country: 



" Some of the trees " (he says) " were ten feet in diameter 

 at the base, and had a bark without a wrinkle; not infre- 



* Tropical Nature, by Alfred R. Wallace, 1878, p. 30. 



