14 ON THE DISPERSAL OF SEEDS BY MAMMALS. 



ground in some places strewn with fruits of various big 

 trees absolutely untouched by animals or birds. In such 

 spots the struggle for dispersal must be very great, and 

 there must be a very large number of seeds wasted. 

 Many trees and climbers in the dense jungle fruit very 

 heavily and one frequently finds (especially where monkeys 

 are absent) the ground beneath these plants almost car- 

 peted with seedlings a short time after the fall of the fruit, 

 but on visiting the same spot a few weeks later only a few of 

 these young plants are to be seen. Nearly all have perished, 

 partly from overcrowding and partly from absence of light. 

 Nor does the waste of young plants end here, for a very large 

 proportion of those that do become trees can never push their 

 branches through the dense mass of older trees so as to be 

 fully exposed to the light, when alone they can flower. 



The contrast between the woods of the colder climates and 

 the jungles of the tropics is most strongly brought out by the 

 wonderful disproportion of species in a given area. In cold 

 climates one freqently sees woods consisting almost exclu- 

 sively of one species of tree such as the beechwoods of 

 Southern England, and the firwoods of Norway, but in a 

 Malay forest all the trees appear to be of different species. 



Indeed it is only in exceptional places which are suited 

 to a limited number of species (such a spot, for instance, as a 

 mangrove swamp) that one sees a large number of individuals 

 of one species together. In the jungles, which are suited to 

 the requirements of a great variety of species, the different 

 individuals are isolated, for here the ground is already so 

 thickly covered with older trees and shrubs, that there are but 

 few vacancies to be filled up. And thus of the immense number 

 of seeds which fall from the trees, but few can find vacant 

 spots on which they can develope into trees. 



The assistance of the wind or of the mammals or birds which 

 dwell in the forests is used to fill up these vacancies. 



The plants which make use of animals to disperse their seeds 

 either possess juicy or fleshy eatable fruits of which the seeds 

 are passed through the bodies of the animals unhurt, or dry nuts, 

 or again the fruits may be adhesive either by some viscid 



