DERIVATION OF THE FLORA AND FAUNA 379 



therophytes, but they have not spread to the islands although many have special 

 dispersal mechanisms, and they were not available at the time when the supposed 

 connection with the mainland existed before the final uplift of the Andes. 



The existence of many aberrant genera and species and, above all, the 

 marked difference between the phanerogams of Masatierra and Masafuera shows 

 that there is no exchange between the two islands in spite of the very moderate 

 distance; even the 360 miles separating Masatierra from Chile should, in the 

 eyes of the diffusionists, amount to little if sufficient time be granted. The Mar- 

 quesas Islands, situated much farther away from the continent, have a less peculiar 

 angiospermous flora than Juan Fernandez; the very opposite ought to be expected 

 if overseas migration had played the dominant role. The absence of the flora 

 of Central Chile speaks against the efficiency of the natural dispersal agents. 

 These circumstances are in favour of the opinion that the volcanic islands arose, 

 not from the depths of the ocean, but on a piece of land formerly connected 

 with South America and not sunk until the newborn islands, now reduced to 

 ruins, had become a refuge for the ancient continental fauna and flora. 



It is also true that several large and widespread families are lacking, such 

 as leguminous plants (with one exception) and lilies, well developed in Chile, 

 but they belong to the modern Chilean flora. 



The plant world of oceanic islands is described as a haphazard collection 

 of waifs and strays, and this is said to explain why so few genera contain more 

 than a couple of species. But would not the result be the same if the actual 

 islands originated through volcanic activity on a sinking land.? Chance would 

 decide what took possession of the new soil, and different sets find a refuge 

 on Masatierra and Masafuera. 



We know that of the mammals introduced by man the goat thrives and 

 multiplies since 400 years and quickly became naturalized. There were no goats 

 on the mainland when the land-bridge existed, but there may of course have 

 been some primitive mammals; if any of them reached the islands, they have 

 disappeared long ago. The islands, as we see them, appear never to have offered 

 great possibilities for the subsistence of a mammalian fauna. They are very small 

 and as there was litde open land there cannot have been any grazing grounds 

 worth mentioning before man altered the landscape. Even after the ground has 

 been cleared on all the lower slopes, pasture is miserable, and one valley after the 

 other has been turned into a desert by the ravages of sheep and cattle. If left 

 to run wild and multiply, the final result can be foreseen. Carnivorous animals 

 need a prey, and there was none. The same is true of snakes which should 

 thrive well now since the domestic rats and mice have been introduced. 



Chile's mammalian fauna is poor and nobody knows if the huemul, the pudu, 

 the Chilean rodents and small marsupials would be able to make a living on 

 Juan Fernandez. Reptiles are poorly represented in Chile, there is not a single 

 tortoise, very few snakes and a dozen lizards. Amphibians are few, but toads 

 and frogs occur. Among the invertebrates are several orders, the chances of which 

 successfufly to get transported across the sea are very doubtful or, as far as we 

 can see, none at all. 



