Stewart—Botanical Conditions pn the Galapagos Islands . 315 
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 
Cryptocarpns 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 Rhizophora 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 
more or 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, Lantana 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 
