290 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
in the hollows rather than on the hilltops may be entirely accounted 
for by the wind movements. The rounded hills are wind worn, and 
there are no gullies due to rushing water. It is noticeable that it 
is the northern shore that has the gradual slope, and the southern 
that is precipitous. This of course is due to the fact that the prevalent 
wind is from the northeast rather than from the south. 
As to the vegetation that occurs on such an island it is either adapted 
to a life on the salt seashore or suited to withstand extreme drought 
inland. The land spit on the eastern end is bordered on the inside 
shore by mangroves. The beach about the "salina" or salt lake 
produces the customary Batis, Salicornia, Trianthema, and Alter- 
nanthera. On the inland side of the salt plain the bushes of Castela 
are abundant. Cassia hispidula is scattered here also. Pavonia 
cochensis is abundant in the sandy valley back of San Pedro. The 
valleys are characterized by the low Pereskia trees, the Acacias, and 
Gomphia, Guaiacum, Pithecolobium, and the largest of the trees, 
Bvmelia cnneata, about three meters high. The smaller plants here 
are Jatropha gossypifolia, Solanum polyacanthos in the valleys; Croton, 
Argithamnia, Opuntia, INIelocactus, and Waltheria on the rocky 
hillsides or hilltops; and in the most rocky as well as in sandy places 
Sti/hsojithes viscosa, the most abundant plant on the island. 
Of all the foregoing plants only one, Argithamnia cochensis, is ex- 
ceptional in color. This is dark red throughout. The other plants 
are gray at least as to the trunk and stem, and the leaves are a gray- 
green and either protected by dense pubescence or are leathery. 
There appeared to be no plants of economic importance on the 
island. A few straggling palms are in the village of San Pedro, but 
they appeared to be neither in flower nor in fruit. 
At the time of our visit, the only plants in bloom were Stylosanthes, 
Caesalpinia, and Bumelia. On Gomphia many dried remnants of 
fruits still remained. This, together with the fact that several trees 
showed signs of budding, suggests that at another time more flowers 
and possibly more plants might be found. As a matter of fact no 
annuals Avere collected, but all were plants with extremely long and 
w'oody roots. Some specimens of Stylosanthes which were but 8 cm. 
in height above ground had roots 22 cm. long. 
This collection while meager in its specimens probably repre- 
sents well the flora of the island. The result may be summarized as 
follows : — 
