382 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th See. 



Anona cherimolia* 

 Anona glabra 

 Caesalpina bonducella 

 Euphorbia pilulifera 

 Ricinus communis* 

 Hibiscus tiliaceus 

 Ipomoea Bona-nox 

 Ipomoea Pes-caprae 

 Coifea arabica* 



From the above presentation it can be seen that the species 

 common to the two groups of islands are for the most part 

 those of rather wide distribution, and owing to the relatively 

 small size of most of them, the general appearance and make-up 

 of the two floras is but little influenced by them. The species 

 which make up the bulk of the vegetation, especially the larger 

 vegetation, are totally different on the two groups of islands — a 

 fact which may have some significance. 



In a paper written some years ago by Dr. George Baur,t 

 an attempt was made to establish a former land-connection 

 between the Galapagos Islands and the American continent, 

 the connection presumably having been somewhere in the 

 Mexican region. The improbability of such a connection has 

 already been shown,! and it seems that the great difference in 

 the floras of Cocos and the Galapagos islands strongly opposes 

 Dr. Baur's view. 



If there has ever been a land-mass connecting the Galapagos 

 Islands with the mainland of North America, it must evidently 

 have included the Cocos Island region, since its position is 

 such that no considerable land-mass could have existed in this 

 part of the ocean without including it. While the climatic 

 conditions on the lower parts of the islands of the Galapagos 

 group are entirely different from that of Cocos Island, being 

 dry in one and moist in the other, the middle and upper por- 

 tions of the higher islands of the Galapagos are moist, and 

 capable, in places at least, of supporting fully as mesophytic 

 vegetation as is Cocos — a fact which is evinced by the pres- 

 ence of eleven ferns common to the two. A former land- 



* Probably introduced through cultivation into both the Galapagos Archipelago and 

 Cocos Island. 



t American Naturalist, v. 25, 310 (1991). 



t Stewart. Proc. Calif. Acad. Sci. 4th Ser. v. 1, No. 2, pp. 233-239. 



