THE VEGETATION OF THE JUAN FERNANDEZ ISLANDS 



931 



Fig. 41. Looking down Quebrada del Pastro, Masafuera, from its source toward the sea. Alpine 

 heath with abundant Lophosona. — Photo 5 3 191 7. 



ticularly Lophosoria, patches of Gumiera and abundant Ani/ioxant/nnn odoralum, 

 see PI. 105: I. Physiologically, it is of course no savanna at all, but a heath, in- 

 vaded by Anthoxanthum. At about i lOO m Dicksonia falls back, but small groups 

 and single specimens of low stature are found also higher up. This is what I 

 have distinguished as a Subalpine belt, and it is well developed in the south 

 section of the table-land, but north of Ouebrada del Ovalo little Dukso7iia is 

 found. The Lophosoria-Anthoxcvitlmvi-Gunnera community is a complex and should 

 perhaps be regarded as a mosaic of three sociations, each with its own dominant, 

 with different demands on soil moisture. Anthoxanthuni forming pure carpets on 

 the drier soil and Guinieva preferring more humid depression or places where 

 water trickles down (Figs. 40, 41). It forms pure societies on wet canyon walls 

 and on the high western barranca (PI. 109: 2). In the high country east and 

 south of Los Inocentes, clouded over most of the time and supposed to receive 

 more rain than the country north of the Barril ridge, the closed Dicksojiia forest 

 ascends high up; seen from the summit it seems to form an unbroken cover 

 over the ridges and gulches, leaving little room for a "savanna" of the kind 

 described. 



The transition from a Subalpine to an Alpine region is almost imperceptible. 

 Some Alpine species are occasionally found at lower altitudes, but the majority 

 make their appearance in about iioom, a level selected as a suitable lower 

 limit of an Alpine belt, but it must not be forgotten that the Lophosoria-Anthox- 

 anthuni- Gunner a complex still reigns supreme, and that the Alpine species do 



