In short, the coconut-palm comes under the general rule, that botanical species are built up of a number of sharply distinguishable types, which prove their constancy and relative independence by their wide distribution in culture. In systematic works all these forms are called varieties, and a closer investigation of their real systematic value has not yet been made. But the question as to the origin of the varieties and of the coconut itself has engrossed the attention of many botanists, among whom are De Candolle in the middle of the last century, and Cook at its close. Both questions are closely connected. De Candolle claimed an Asiatic origin for the whole species, while Cook's studies go to prove that its original habitat is to be sought in the northern countries of South America. Numerous [85] varieties are growing in Asia and have as yet not been observed to occur in America, where the coconut is only of subordinate importance, being one of many useful plants, and not the only one relied upon by the natives for their subsistence. If therefore, De Candolle's opinion is the right one, the question as to whether the varieties are older or younger than the cultivated forms of the species, must always remain obscure. But if the proofs of an American origin should be forthcoming, the possibility, and even the probability that the varieties are of later date than the beginning of their culture, and have originated while in this condition must at once be granted. An important point in the controversy is the manner in which the coconuts were disseminated from shore to shore, from island to island. De Candolle, Darwin and most of the European writers claim that the dispersal was by natural agencies, such as ocean-currents. They point out that the fibrous rind or husk would keep the fruits afloat, and uninjured, for many days or even many weeks, while being carried from one country to another in a manner that would explain their geographic distribution. But the probability of the nuts being thrown upon the strand, and far enough from the shore to find suitable conditions for their germination, is a very small one. To insure [86] healthy and vigorous seedlings the nuts must be fully ripe, after which planting cannot be safely delayed for more than a few weeks. If kept too moist the nuts rot. If once on the shore, and allowed to lie in the sun, they become overheated and are thereby destroyed; if thrown in the shade of other shrubs and trees, the seedlings do not find the required conditions for a vigorous growth.