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, 

 Bumelia cuneata, about three meters high. The smaller plants here 

 are Jatropha gossypifoUa, Solanum polyacanthos in the valleys; Croton, 

 Argithamnia, Opuntia, Melocactus, and Waltheria on the rocky 

 hillsides or hilltops; and in the most rocky as well as in sandy places 

 Stt/losanthes viscosa, the most abundaiit 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 were collected, but all were plants with extremely long and 

 woody 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 : — 



