282 ORIGIN AND DISTRIBUTION OF THE COCOA PALM. 



yet the banana is seldom, if ever, able to establish itself as a wild 

 plant in tropical lowlands, for the reason that wherever it will grow 

 shrubs and trees will also thrive and choke it out in a few years. 

 The case is much the same with the cocoanut, except that in the course 

 of a century the signs of human agency would more effectively dis- 

 appear. It is not sufficient to find cocoa palms far from existing 

 human habitations; the question is whether the species could really 

 maintain itself without human assistance and protection against other 

 vegetation. Obviously this can not be determined by simple inspec- 

 tion, but a satisfactory experiment might require careful records car- 

 ried over at least two or three generations of men and palms. The 

 probabilities are, however, overwhelmingly against the continued 

 independent existence of the cocoa palm at sea level anywhere in the 

 moist Tropics. It is true that if planted by man it will grow in many 

 places where it would never plant itself, and it might also maintain 

 itself in places where the proper conditions were continued by human 

 agency. In undisturbed nature, however, the extermination of the 

 cocoanut by the encroachment of the tangled masses of vegetation 

 which invade tropical beaches would probably require but a few cen- 

 turies. This idea is recognized in the Cingalese proverb, "The cocoa- 

 nut will not grow out of the sound of the sea or of human voices," and 

 in the belief held among the same people that the trees will not thrive 

 unless "you walk and talk amongst them." 



Although the cocoa palm furnishes an extreme instance, this require- 

 ment of open ground is not peculiar to it, but is general in this entire 

 natural order, the members of which, with the exception of the climb- 

 ing genera, are unable to survive under genuine jungle or forest 

 conditions. The large, long-leaved species are particularly at the 

 mercy of tangled tropical vegetation, since it is impossible for them 

 to make the rapid growth necessary to keep up with trees of other 

 plant families. The arboreal palms are first required to produce a 

 long succession of leaves at the level of the ground, their trunks 

 making no upward growth until the full diameter has been reached, 

 which seldom requires less than three years. On complete^ barren 

 islands * seedling cocoanuts might continue to nourish, but if the space 



*Dr. Treub has reported (Ann. Jard. Bot. Buitenzorg, vol. 7, p. 217, 1888) the find- 

 ing of a cocoanut on the beach of an island formed by the eruption of Krakatoa, but 

 no intimation is given that it had germinated or was alive. 



The very small and remote Keeling Islands of the Indian Ocean offer, perhaps, the 

 most probable instance of spontaneous occupation by the cocoa palm, but even here 

 the assertion of the absence of human agency is limited to the denial of ' ' permanent 

 inhabitants" earlier than the nineteenth century. Moreover, there seems to have 

 been but one other arboreal species ( Cordia subcordata ) which has become numerous, 

 and this was confined to the interior of the islands, leaving the coast districts to the 

 uncontested monopoly of the cocoanut. These islands have been studied by Darwin, 

 Forbes, and Guppy, and the last mentions (Journ. Trans. Victoria Inst., vol. 24, 



