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 arca. In cold climates one freqently sees woods consisting almost exclu- sively of one species of trec 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 secs 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
