Stewart — Botanical Conditions pn the Galapagos Islands. 31? 



of soil occurs in various places which has resulted from the 

 breaking down of the lava. The most of the soil has probably 

 been washed from above as it usually occurs in low places. The 

 most of the isalnd has but very little soil on it, and the surface is 

 strewn with fragments of lava. 



The beaches are rather steep here in consequence of which 

 there is not a great amount of halophytic vegetation. Bushes of 

 Cryptocarpus pyriformis occur on the sand beaches, and at vari- 

 ous other places near the shore. Patches of these bushes form 

 about the only green vegetation during the greater part of the 

 year, and they stand out sharply when the island is examined 

 from the top of one of the hills in the interior. Sesuvium Ed- 

 monstonei grows here but usually not under halophytic condi- 

 tions. The mangrove vegetation is confined to a small thicket 

 of bushes of Rliizophora Mangle which occur on the northeast 

 side of the island below Gardner Bay. The beach, in the vicin- 

 ity of these mangroves, was strewn with pieces of bamboo, co- 

 coanut husks, and other drift, showing that this area receives a 

 moreor less constant supply of such material. 



Other plants which occur on or near the beaches are : Cacabus 

 Miersii, Cenchrus distichophyllus, Coldenia fusca, Discaria pau- 

 ciflora, Maytenus obovata, and Vallesia glabra. 



The only trees of any size on the island are those of Bursera 

 graveolens and Opuntia galapageia. The Opuntias have rather 

 low thick trunks and closely arranged branches. Goats, which 

 have been introduced upon this island within the last few years, 

 eat off all of the lower Opuntia branches, and they even eat into 

 the thick trunks in some instances. As these plants form their 

 only suitable food and probably their only source of water, 

 for several months of the year, there is danger of this species 

 being exterminated on this island in time. 



The most of the vegetation on the island consists of bushes, the 

 most common of which are: Acacia macracantha, which forms 

 small trees in protected places, Cordia lutea, Croton Scouleri, 

 Gossypium barbadense, Lautana peduncularis, Parkinsonia acu- 

 leata, and Prosopis dulcis. These bushes occur in patches in 

 many places in between which there are open spaces which are 

 probably covered with grasses and annual herbaceous plants 

 during the rainy season. By following these open spaces one can 

 travel over the most of the island without much difficulty. 



There are some indications of a greater amount of moisture 



