950 PATAGONIAN EXPEDITIONS I BOTANY. 



a privileged country, where the climate is free from extremes, where the 

 moisture is sufficient, where forests, easily penetrated, adorn the mountain 

 sides" (Gallois, Les Andes de Patagonie}. 



The striking phenomenon of the existence of plants of the same or of 

 closely allied species in unconnected localities, attracted the attention of 

 the older botanists and became a subject of speculation. The doctrine 

 of Schouw, reinforced by Louis Agassiz, that these cases were to be 

 explained by the creation of the original members of a species in dupli- 

 cate, or in multiple, was promptly opposed by Joseph D. Hooker, whose 

 researches into the Antarctic flora made it clear that there must be means 

 of distribution whereby the plants of some of the regions could reach 

 other regions. He argued (Flora of New Zealand, 1853), that the indi- 

 viduals of every species have been distributed from one center, and that 

 species must have originated in particular centers, whence they were 

 spread, as opportunities occurred ; also that their scattering was by natural 

 causes, but not necessarily in all cases by the same causes to which they 

 are now exposed. Asa Gray subsequently endorsed and illustrated these 

 views (Flora of Japan, 1859, reprinted in Gray's Scientific Papers, II, 

 126 sqq.) insisting on the local origin of species, and on their migrations 

 from one place to another, often under the pressure of climatal changes. 

 The writings of Charles Darwin and Alfred Russell Wallace, substantially 

 settled this controversy, by showing that in order to explain the present 

 distribution we must consider the opportunities or difficulties of access of 

 plants from other regions. Thus Darwin, and afterwards Ball, observed 

 that the absence of trees in the Patagonian plains was due to the land 

 having been recently submerged, and that there was no neighbouring 

 country from which after emergence it could be stocked with suitable trees. 



These considerations taken along with the xerophytic climate of the 

 eastern plains led us to expect a very poor flora. But on including the 

 western slope, and the islands on the west and south, the number of species 

 of flowering plants in the Patagonian-Fuegian Region turns out to be 

 about 2,100, with about 350 good varieties in addition. This is the same 

 total as that made out for Victoria in Baron Mueller's analytic summary, 

 and we regard it as a favorable showing for Patagonia. The number of 

 genera is 522, belonging to 113 families. Of these the Gymnosperms 

 have 12 species in 7 genera. The Monocotyledones have 481 species and 

 85 varieties; 106 genera, and 17 families. Gramineae alone number so 



