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C. SKOTTSBERG 



volcanic soil. It goes without saying that chance played a dominant role and that 

 the fragmentary character of the island world is easy to understand. It is also 

 possible to understand why different species happened to become isolated on 

 Masatierra and Masafuera. According to Jonow Masafuera was populated through 

 overseas transport from Masatierra, and this explained why the former was so 

 much poorer, but only 50% of the vascular plants found on Masafuera were known 

 to him. Other reasons for the dissimilarities between the islands are differences 

 in the topography, particularly in altitude, Masatierra is 915, Masafuera 1570 m 

 high. If we could lower Masafuera 650 metres, the entire highland region with 

 its special flora and fauna would disappear. The question of the origin of the 

 alpine flora is, as we have seen, clifticult to answer. Did it exist in the islands 

 before the separation from Chile took place, and were there any habitats where 

 it could thrive.^ Many of the species are of Antarctic origin and immigrated to 

 the extreme south of America, with or perhaps after the XotJiofagus flora, where 

 they abound in tlie bogs of the rainy zone and in the mountains above the 

 timberline. And if, as was explained above, the Xothofagns flora never had an 

 opportunity to spread to Juan Fernandez over land, nor were those Magellanian 

 plants able to come. There are several montane plants in Masafuera which un- 

 doubtedly date back to early times, but they are of different origin: the species 

 of Erigeron, Euphrasia formosissima, j\Iegalachne iiiasafucrana, PItoenicoseris regia. 

 Ranunculus caprarum and Robinsonia Masafuerae, all of them peculiar endemics, 

 and of these Raitunculus and Megalachne are found only along the high ridge 

 above 1300 m. Even if some of them are of Antarctic ancestry, their history is 

 another. When it comes to the Magellanian group, Oreoboius, Lagenophora, 

 GleicJienia, and so forth, it is difficult to exclude the possibility that they be 

 glacial or postglacial immigrants. Carex Banksii, Euipeiruni rubrum — only a single 

 plant seen — Galium niasafueranuin, GnaphaliuDi spiciforme, JMyrteola 7iininnularia 

 and Rubus geoides are, as was already told, not of Antarctic origin, but may have 

 extended far south after the recession of the ice and accompanied Oreoboius, etc. 

 And we cannot refuse to admit that various Chilean ferns, bryophytes and lichens, 

 belonging to the forest, were transported across from South Chile, for even if the 

 prevailing winds are westerly, storms from other directions occur, and there has 

 been plenty time. Still, the floristic difference between the two islands is a warning, 

 not to put too much faith in the efficiency of the natural agents, among which, 

 in this case, the wind stands foremost. 



The biological differences between Juan Fernandez and the mainland increased 

 during the Ice Age. West Patagonia and Fuegia were covered by inland ice [i6f)\ 

 if small, ice-free refuges occurred has not been definitely stated, but is not alto- 

 gether improbable; their part taken in the repopulation of the country w^as, however, 

 of minor importance. With the north-south trend of the Cordillera, the road toward 

 north lay open, and the big island of Chiloe was not ice-covered, allowing the 

 subantarctic flora and fauna to survive, perhaps also some of the hard}' trees and 

 shrubs. The high crests of the Andes in Central Chile were covered by glaciers 

 descending into the valleys; squeezed between the mountains and the coast a 

 migration back and forth went on during the successive interglacial and glacial 



