200 ALBAN STEWART 



that he thought it had been introduced from Panama. I found 

 it only in the cultivated region around Wafer Bay. It would 

 seem that Cocos Island should give us the key to the whole 

 situation. Baur evidently considered this to be the most likely 

 part of the ocean in which to construct his land bridge, as he 

 states 20 that the 4000 m. line connecting the Galapagos with 

 the central American coast, extends through Cocos Island. If 

 such a land connection had ever existed it. is very likely that 

 there would be a much greater similarity in the floras of the two 

 islands than is the case, as the climatic conditions are not so 

 dissimilar but that eleven species of ferns are common to both. 



A relationship, though remote, between the floras of the 

 Galapagos and Hawaiian Islands, is implied by Scharff.- 1 We 

 unfortunately have no very recent complete flora of the Hawaiian 

 Islands, but from what is known I find that there are approximate- 

 ly twice as many of the Galapagos genera represented upon the 

 Hawaiian Islands as there are Galapagos species. This is a 

 relationship that is about as remote as it well could be, and if 

 we exclude the single species of the Hawaiian genus Lipochaeta, 

 which occurs on the Galapagos Islands, the relationship is prac- 

 tically nil. Hillebrand, in his work on the Hawaiian flora 

 extending over a period of years, found no reason to believe 

 that the Hawaiian Islands were ever less isolated than they 

 are now. The water between these islands and the American 

 continent is uniformally 3000 fathoms deep according to Hille- 

 brand. To try to establish a land connection between these 

 islands and the Galapagos, either directly or indirectly, seems 

 to be preposterous so far as the botanical evidence shows. 



My work on the Galapagos flora has led me to strongly be- 

 lieve that the only way we can account for its origin is through 

 the chance methods of distribution of seeds and spores over 

 large bodies of water. If we must invoke the aid of geographical 

 changes to account for all the anomalous biological conditions 

 that we find, truly the Pacific Ocean would look like a spider- 

 web if the ghosts of all the supposed land-bridges should suddenly 

 rise up to confront us. 



20 Baur. /. c, p. 221. 



21 L. c, p. 317. 



