FLORA OF THE PERUVIAN ANDES. loi 



botanist from Europe to find so large a proportion 

 of the indigenous plants belong to types which 

 characterize the mountain vegetation of our continent. 

 Of the genera in which the plants collected by me 

 are to be classed, fully one-half belong to this category, 

 and these genera include more than an equal pro- 

 portion of species. I find, indeed, that fully sixty per 

 cent, of the species in my collection belong to European 

 genera, but that, with trifling exceptions, the species 

 are distinct and confined to the Andean region. The 

 reasonable conclusion is that the types which are thus 

 common to distant regions must be of very great 

 antiquity, and that the ancestors of the existing species 

 must have spread widely at a very remote period of 

 the world's history. Most of the plants in question 

 belong to genera having very numerous species, of 

 which it may be presumed that the parent forms 

 possessed a strong tendency to variation. 



The only tree seen at Chicla is a species of elder — 

 Sambucus Peruviana of botanists — not widely differing 

 from the common black elder of Europe. 



Along with the numerous allies of the Old-World 

 flora that characterize the indigenous vegetation, it 

 was somewhat remarkable to find, in the upper valley 

 of the Rimac, a number of cosmopolitan weeds, most 

 of them common in Europe, which appear to have 

 become thoroughly naturalized. Most of these, which 

 are also found in the coast region of Peru, were un- 

 doubtedly introduced by the Spaniards ; but there are 

 a few, such as the common chickweed, whose wide 

 diffusion throughout the world seems to me to be 

 more probably due to transport by birds. 



