422 C. SKOTTSBERG 



•of 300-400 m, sufficient, one would think, to create a humid montane belt with 

 fairly luxuriant arboreous vegetation, but of tliis there is nothing, in any case 

 nothing left. Rains are frecjuent, and the amount of precipitation is not small, 

 but evaporation, favoured by high temperatures and the strong S.E. trade wind, 

 is great and most of the water rapidly disappears underground. The climax vege- 

 tation is an oceanic steppe-like meadow or grass heath, as some would prefer 

 to call it (J42]. The flora docs not present many of the characteristics of oceanic 

 islands. There are no endemic genera, no peculiar endemic species, no prepon- 

 derance of woody {)lants; Sof^Jiora is the only tree and Lychnn the only shrub; 

 the flora is herbaceous, comj^rising few therophytes but many annual weeds. The 

 ratio species : genus is 1.2 : i. With the exception of Gra7uin€ae, which dominate, 

 and Cvpcraccac (some of these perhaps not indigenous) most large and world-wide 

 families are absent, even Compositae; there are no conifers, no orchids but a fair 

 number of ferns: in these respects the island conforms to typical oceanic islands. 



On the other hand, luister Island has little in common with the low islands, 

 atolls or other coralline structures with no rock foundation exposed, where en- 

 <lemics are, as a rule, absent and the fragmentary flora consists of species easily 

 transported by the natural agencies and by man. 



The geographical position is unfavourable to immigration, the chances for 

 the arrival of seeds from America small, the distance being 3700 km, and 1850 

 km separate I^^.aster from Pitcairn, the nearest basaltic islet. On the other hand, 

 the chances for establishment ought to have been good: new surroundings, though 

 perhaps not very varied, plenty of space, no competition, conditions furthering 

 the evolution of new s})ecies and genera as many biogeographers believe, but 

 nothing like that seems to have happened on Easter Island. The objection will 

 be raised that we do not know, for the bulk of the original fauna and flora may 

 luue been destroyed by man and will remain unknown — but is it not surprising, 

 if this be true, that no peculiar, systematically isolated form was preserved to 

 our da\-s.- After all, |)erhaps not. Truly, in many high and well populated Poly- 

 nesian islands endemics are plentiful, growing on the elevated ridges, on the 

 precij)itous mountain sides, in the deep recesses of the gorges where cascades 

 tumble down or even in less inaccessible, but uninhabited places, but the topo- 

 graphy of I'.aster Island is different and I can see no reason why not man and 

 his animals could have succeeded to exterminate practically everything of the 

 original nature except the lichens and mosses covering the rocks and a few herbs 

 and grasses. 



Distance is not the only factor, time is another; the island is, somebody 

 will say, perha|)s too )-oung. It has a youthful appearance, the craters are well 

 |)reserve(l, but the\- are secondary and not responsible for the origin of the island, 

 and their well-preserved shape is no proof of youth. There is no sign of recent 

 activity — I^^)KsrKR's idea that the decay during the 1 8th century of the old ab- 

 original culture was due to some volcanic catastrophe lacks foundation. As there 

 are no permanent streams, erosion must be slight. I'he various raiws and other 

 cones may be old enough and the foundation, on which they stand, very ancient. 

 As BkifJGKX says (.?,v. 290): 



