196 ALB AN STEWART 



times, or at least since the different islands became separated 

 from each other. There are upon these islands some two hun- 

 dred and sixteen species, varieties, and forms of plants, or 35% 

 of the flora, which are confined to a single island. Of these one 

 hundred and one species are endemic, leaving one hundred and 

 fifteen species, or about 18% of the flora with a wider distribu- 

 tion on the mainland. It is likely that further collecting upon 

 the islands will extend the range of some of these species, but a 

 large number of them must be confined to a single island, as 

 many are of such a size that they would hardly be overlooked 

 by even the most casual collector. Sapindus Saponaria L. 

 is a conspicuous example of this class. There is such a similarity 

 of climatic conditions at like elevations on many of the islands, 

 as well as a similarity of soil, that it is improbable that so many 

 species would be confined to such restricted areas if they had been 

 present upon the islands before their final separation from each 

 other. Furthermore, each succeeding expedition to the islands 

 brings back a considerable number of species not before known 

 to occur there, which have a wider distribution on the main- 

 land. This might indicate that there is a more or less con- 

 stant introduction of plants by the various agencies of chance 

 distribution. 



There are a number of erroneous ideas prevalent concerning 

 the botanical conditions on these islands, among which is the 

 supposed alpine flora. This idea has probably arisen through 

 Wolfs' 11 observations on Charles Island. This author states 

 that the vegetation at an elevation of 900 feet on this island bears 

 a striking resemblance to the vegetation in the Andes mountains 

 at an elevation of 9000 feet, a statement that was seized upon 

 by Baur 12 to support his subsidence theory. If Wolf had made 

 his observations at similar elevations on either the south side 

 of Albemarle or Indefatigable Islands, or, at a somewhat higher 

 elevation on James Island, he would have found the conditions 

 entirely different from those he describes, and might have con- 

 cluded that the general make-up of the vegetation was more like 



11 Die Galapagos Inseln, pp. 257-260. 



12 L. c, p. 309. 



