LIMITS OF SPECIES 175 



of Pinos, in the same plains. We also find pines in the 

 south-eastern part of the island of Cuba, on the declivity 

 of the Copper Mountains, where the soil is barren and 

 sandy. The interior table-land of Mexico is covered with 

 the same species of coniferous plants ; at least the specimens 

 brought by M. Bonpland and myself from Acaguisotla, 

 Nevado de Toluca, and Cofre de Perote, do not appear 

 to differ specifically from the Pinus occidentalis of the West 

 India Islands, described by Schwartz. Now those pines 

 which we see at sea level in the island of Cuba, in 20 and 

 22 of latitude, and which belong only to the southern part 

 of that island, do not descend on the Mexican continent 

 between the parallels of 17^ and 19, below the elevation 

 of 500 toises. I even observed that, on the road from 

 Perote to Xalapa, in the eastern mountains opposite to the 

 islaod of Cuba, the limit of the pines is 935 toises ; while 

 in the western mountains, between Chilpanzingo and Aca- 

 pulco, near Quasiniquilapa, two degrees further south, it is 

 580 toises, and perhaps on some points, 450. These ano- 

 malies of stations are very rare in the torrid zone, and are 

 probably less connected with the temperature than with the 

 nature of the soil. In the system of the migration of plants, 

 we must suppose that the Pinus occidentalis of Cuba came 

 from Yucatan before the opening of the channel between 

 Cape Catoche and Cape San Antonio, and not from the 

 United States, so rich in coniferous plants ; for in Florida 

 the species of which we have here traced the botanical 

 gcoc^aphy, has not been discovered. 



About the end of April, M. Bonpland and myself, having 

 completed the observations we proposed to make at the 

 northern extremity of the torrid zone, were on the point of 

 proceeding to Vera Cruz with the squadron of Admiral 

 Ariztizabal; but being misled by false intelligence re- 

 specting the expedition of Captain Baudin, we were induced 

 to relinquish the project of passing through Mexico on our 

 way to the Philippine Islands. The public journals 

 announced that two French sloops, the " Geographe " and 

 the " Naturaliste," had sailed for Cape Horn; that they 

 were to proceed along the coasts of Chili and Peru, and 

 thence to New Holland. This intelligence revived in my 

 mind all the projects I had formed during my stay in Paris, 



