954 PATAGONIAN EXPEDITIONS: BOTANY. 



Kerguelen, Australasia, New Zealand and southern Africa. It is mainly 

 through the Andine connection that it is remotely but very decidedly 

 related to the Vegetation of Western North America and of Siberia and 

 Central Asia. 



The transverse course of the Patagonian river-valleys from the Cor- 

 dilleras to the Atlantic Ocean, taken along with the fact that the xerophil 

 climate and shingly plains practically confine the vegetation to these river- 

 valleys, renders the flora of the northern and central parts of the region 

 almost absolutely dependent on the constant replenishing from the 

 Andine chain and elevated valleys. When the occupants of the trans- 

 verse valleys become extinct, either being buried under the mountain 

 debris in consequence of floods, or being carried out to sea, they are 

 dependent on the arrival of a new stock of similar or diverse species to 

 fill the vacancy. 



Professor Neger summarizes the relations by stating that the Andine 

 shingle-flora sends down many species to the Patagonian steppes, and in 

 the valleys protected from the winds Central Chilian forms determine the 

 character of the vegetation. Thus the Patagonian flora stands to the 

 Central Chilian Flora in closer relations than one would expect, consider- 

 ing the intervening mountain chain. This chain causes great difference 

 between the Chilian and the Argentine Flora ; and yet Patagonia remains 

 in close touch with the Chilian. 



In illustration of this, Neger estimates that Southern Patagonia has 57 

 per cent, of its Dicotyledones in common with Chili ; only 28 per cent, 

 endemic, and even these allied to Chilian forms ; whilst only 15 per cent, 

 are of North Argentine or Brazilian affinity. He also remarks that the 

 comparison of genera is more significant, of which 88 per cent, are 

 Chilian ; a few genera endemic, and less than 9 per cent, unknown in 

 Chili, but found in Argentina or Brazil. We think that these percentages 

 would still be near the truth although the figures in the present list are 

 at least twice the number known to Neger. 



Neger adds that Geology will aid in explaining why the colonizing was 

 not chiefly from Argentina, though no high mountain barrier intervenes in 

 that direction. This depends on the fact that Patagonia was recently 

 under the sea, and after emerging, its river valleys running from west to 

 east carried the immigrant plants across from the Chilian Andes. He 

 notes that the flourishing European apple-trees of Patagonia prove that 



