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of six months, the tree does not succeed in growth, the amount of 

 latex is smaller, and a planter would soon find out that he had 

 made a great mistake, had he tried this experiment on a large 

 scale. It seems to me probable that if attention had been paid to 

 this circumstance, Castillo, would be more of a favourite than it is. 

 We are working on this problem at La Zacualpa Botanical 

 Station. Herbarium specimens are secured of Castillas from 

 various parts of Central America, and seeds of different varieties 

 are being planted in the experimental plots. In clue time we 

 expect to be able to throw some light on this question. Seeds of 

 our local Castillo, lactiflui have been sent to various places in the 

 West Indies, to British Guiana, Gold Coast and other places in 

 West Afriea, Ceylon, Java, Queensland, Philippines and Hawaii, 

 and I expect to obtain reports upon the progress and development 

 of the plant under the different conditions prevailing in these 

 different countries. 



THE GEOGRAPHICAL DISTRIBUTION OF CASTILLA. 



Costilla grows wild from 21" north latitude in Mexico southward 

 through Guatemala, Honduras, San Salvador, Costa Rica, Nicar- 

 agua, Panama, and also in North-Western South America. The 

 area in Mexico is a belt ranging from ten to one hundred miles in 

 width and extending from the port of Tuxpan in the north to the 

 western boundary of Campeche, a distance of about 500 miles. 

 The extent of the rubber belt is also rather small in Central 

 America, where it can be said to follow the Cordilleras on both 

 sides, while in South America it grows on the western slope of 

 the Andes of Ecuador and Peru. 



Costilla rubber is generally known in the market as " Centrals" 

 but it derives many other names from the countries and localities 

 in which it is found growing. Thus it is called Peruvian caucho, 

 Guayaquil rubber, Barranquilla, Darien, Panama, Cartagena, 

 Honduras, Nicaragua, West Indian, Guatemala, and Mexican 

 rubber. 



The most common species is Castillo elastica Cervantes, but 

 other species such as C. markhamiana and C. tunu occur in different 

 regions. The question of the geographical distribution of the 

 various representatives of the genus Costilla is not yet sufficiently 

 investigated. 



On the Isthmus of Panama the Castillo is quite common in some 

 districts. Mr. CROSS writes about its occurrence in this country : — 



" The Caucho tree grows not in inundated lands or marshes, 

 but in moist, undulating, or flat situations, often by the banks of 

 streamlets and on hillsides and summits where there are any 

 loose stones and a little soil. It is adapted to the hottest parts 

 of India, where the temperature does not fall much below 

 74° F. The tree is of rapid growth, and attains a great size, 

 and I am convinced that when cultivated in India, it will answer 

 the most sanguine expectations that may have been formed 

 concerning it. I have been up the Chagres and Gatun rivers. I 



