THK VEGETATION OF THE JUAN FERNANDEZ ISLANDS 



Table XX1\'. Leaf-size classes. 



829 



All species . . . 

 Forest species 

 Alpine » 



Number of 

 species 



146 

 1^5 



Leaf-size in % of total number of species 



9-5 



8 



19 



meg 



2.4 



*;ooseberries etc. are grown with more or less good result, peaches, quince, chestnut, 

 figs, grapes, artichokes and maize do well, Eucalypt7is globulus, Pinus radiata, 

 AlhizzJa loplianta are cultivated, Zmitedeschia aethiopica, Ricinus coiiimmiis, Pelar- 

 gonium spp., Tropaeolum uiajus etc. have become naturalized, but Citrus fruits 

 have failed. Nevertheless, the very high Ph percentage ought to correspond to 

 a subtropical climate with sufficient precipitation. On the other hand, the islands 

 lie within the zone of winter-rains, and we have already seen that there is con- 

 siderable resemblance between the climates of Masatierra and of the Macaronesian 

 Islands. The biological spectra, taken from Raunkiaer [6] are given in Table XXI 

 and compared with the spectrum for Masatierra; I have added the spectrum for 

 the Mediterranean island of Samos after Raunkiaer 2.55. 



Compared with the resemblance in climate, the difference in spectra is much 

 greater than we have reason to expect: the preponderance of Ph in Juan Fernandez 

 stands out, as well as the low percentage of Th. Macaronesia has a Therophyte 

 climate, less evident in Samos, where, on the other hand, G are numerous. Even 

 if the summer is much less dry in Masatierra, the insignificant number of Th is 

 surprising. L. c. I referred to Raunkiaer's statement that if a spectrum is a true 

 expression of the climate it remains unaltered even if we add alien species which 

 have become naturalized and which do not depend on cultivated soil or on the 

 vicinity of settlements for their existance. I reckoned with 36 neophytes regarded 

 as naturalized. Their number has now grown to 87, which have spread outside 

 Valle Colonial on Masatierra, many of them also found on Masafuera, where 

 some species never observed on Masatierra occur. Table XXII shows the life- 

 forms in % of the total number of indigenous, adventitious and indigenous + ad- 

 ventitious species. 



I believe that the last of these spectra, which approaches the spectra for 

 Madeira and the Canary islands, is a more correct expression of the climate 

 than the first. This, then, must be anomalous, and we have to find the reason 

 for this anomaly. L. c. I held the isolated endemics responsible. They have no 

 relatives in South America, whereas several point toward New Zealand and 

 Oceania; together they form part of Engler's "Altozeanisches Element". In Juan 

 Fernandez it is represented by 51 species, 24 of these belonging to 12 of the 

 16 endemic genera. Their biological spectrum shows 9.8 % Me, 27.4% Mi, 43.1 % 

 N, 1 1.7 % Ch, and 7.8 % H. The Ph % is 80.3. It is this element more than any 

 other that puts its stamp on the spectrum and invites us to pay attention to 



