2 
and the tree was named thus in honour of the Spanish botanist 
Castillo , who had died the previous year, while he was working on 
a flora of Mexiop, In 1805 an English translation of the paper 
was published anonymously, and now the name was changed to 
Castilloa . The translator (who is. believed to have been Charles 
Koenig, the keeper of the mineralogical department of the British 
Museum) had no right to alter the name. A Mexican botanist had 
already, with just as little right, proposed to change the name to 
Castella, shortly after the plant had been described. Now we have 
in systematic botany certain recognized rules of nomenclature, and 
one of these is that of priority. As Castilla was the first name 
given, it should remain so. This question was discussed and settled 
in 1903 by O. F. Cook, in “The Culture of the Central American 
Rubber Tree” or Bulletin No. 49, Bureau of Plant Industry, 
United States Department of Agriculture, but it seems to have 
been overlooked. 
Different Forms of Castilla. 
Another question which is. causing considerable misconception 
as regards our Central American rubber tree is that of species. 
Castilla elastica Cerv. in a very wide species, containing numerous 
forms. A species- making botanist could easily divide it into a 
dozen species or more. I have personally observed nine fairly 
distinct forms, but I still hesitate to recognize them as good varieties. 
Koschny, a Costa Rica planter, who has written considerably in 
“ Der Tropenpflanzer ” about Castilla in certain parts of Central 
America, speaks of several “ species,” but does not give satisfac- 
tory descriptions that would warrant his forms to receive the 
distinction of species. Cook described the form occurring on and 
near La Zacualpa rubber plantation in Soconusco, Mexico, as a 
new species, C. lactiflua. In Hawaii I saw a form planted from 
seeds obtained from a seed merchant in Paris under the name var. 
nicamguensis. It Certainly was different from any other form I 
have seen elsewhere. ‘ <d. mqrkhamiatia is generally considered to be 
a separate species, and* the Castilla grown in Ceylon is sometimes 
referred to as this species. Certain is that the Ceylon Castilla is 
not identical to any Mexican Castilla that has come under my 
notice. 
From the planter’s point of view it is of little significance 
whether one or more species are cultivated so long as the rubber is 
obtained. But it is in this fact of the existence of many different 
forms in which we have to find an explanation of the reputed 
failure of Castilla in different places, where its . success had been 
presupposed. 
If we plant seeds of the Castilla of the Atlantic side of Southern 
Mexico, with an almost continuous rainfall, on the Pacific slope of 
the Sierra Madre, where we have a distinct dry season 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 
ircumstance, Castilla would be more of a favourite than it is. 
