CASTILLA IN SOUTHEKN MEXICO. 27 



No wild rubber was seen on the Isthmus of Tehuantepec between 

 "Juile and San Juan Evangelista. The vegetation here indicates a 

 climate dryer than that in the vicinity of Tapachula. The some- 

 what more hardy plants of the rubber belt, Cecropia, Cochlospermum, 

 Attalea, etc. , are present, but the new elements are of the small-leaved 

 desert or dry-climate types, with none of the humid tropical proclivi- 

 ties of the Tapachula region. The forest growth is also much smaller 

 and the woods are more open. 



Two small trees of Castilla were seen midway between San Juan 

 Evangelista and San Miguel, on the new branch of the Vera Cruz 

 and Pacific railroad. They were closely similar to the Pacific coast 

 sort, but appeared rather unusually well fruited for young trees, and 

 the individual ripe fruits seemed exceptionally large. The trees were 

 slender, 1 or 5 inches in diameter, and had not been tapped. The 

 country between the two points mentioned becomes more and more 

 open ; grazing is the only industry. There are occasional Attalea palms 

 in the moister spots along streams, butAcrocomia is the only common 

 palm. Acrocomia may be taken as a good counter-indication of wild 

 Castilla, which seems to flourish only where there is more moisture 

 and a vegetation more luxuriant than Acrocomia can compete with. 



Both to the south and to the north of Perez station rubber trees grow 

 wild, though they occur but sparingly, and all are of very small size 

 compared with those of Soconusco, in keeping with the general reduc- 

 tion of the size and quantity of the forest growth, due probably to 

 inferior soil and drier climate. 



In one instance a large number of trees was seen in a small clump 

 or thicket only an acre or two in area, but notwithstanding the almost 

 complete exposure of many of the trees they were still of very slender 

 habit. When young, however, they doubtless had undergrowth to 

 contend with, but had been able to get well above this, owing to their 

 greater vigor. There is no indication that rubber trees were ever 

 abundant in the region about Perez. This view is also supported by 

 the fact that the existing trees have not been killed or dwarfed by 

 tapping, as in regions where the trees are sufficiently large and numer- 

 ous to make rubber gathering profitable. That Castilla would grow, 

 if planted, in the open grass land about Perez is very probable, but 

 that it would thrive is not so likely, owing to the absence of the rich 

 soil in which it prefers to grow, as seen in the more southern districts. 



The oldest planted rubber trees in the Cordoba district of Mexico 

 are said to be near Tierra Blanca. They are about 9 years old, and 

 were to have been tapped experimentally in June, 1902. Sir Wetman 

 Pearson, the English builder of railroads and harbors on the Isthmus 

 of Tehuantepec, also has a plantation of about 100,000 trees of simi- 

 lar age. 



The- reported permanent moisture of the rubber district of the Isth- 

 mus of Tehuantepec is counter-indicated by the fact that the rubber 



