376 MB. E. M. HOLMES ON CINCHONA. LEDGEUIANA. 



when mature presents a bark distinguishable both by external 

 and internal characters, and that hybrids generally give some 

 indication of the species to which they belong by the characters 

 of the bark. 



My grounds for this belief are the following. Specimens of 

 the different varieties of Calisaya from wild trees and from cul- 

 tivated trees in Bolivia, and from cultivated trees in Darjeeling, 

 can be easily recognized as belonging to one type ; and the same 

 holds good with the typical forms of C. officinalis and C. succi- 

 rubra *. 



As a further illustration that the bark of trees of nearly allied 

 species is easily distinguishable, I may appeal to a specimen of 

 the flowering Ash, Fraxinus Omits, L., now in the Botanic 

 Gardens at Regent's Park, which was grafted many years ago 

 on the trunk of the common Fraxinus excelsior, L. Here the 

 difference in the two barks, above and below the line of juncture, 

 is easily recognized. 



The chemical analysis of Cinchona-bark also gives some clue 

 to the species from which it has been derived, in the relative 

 quantities and character of the alkaloids and colouring-matters 

 prevalent in it. 



So far as I am able to judge from the point of view of the 

 physical characters of the bark, I am prepared to state positively 

 that the Cinchona Ledgeriana from Darjeeling is undoubtedly 

 that of a form of Cinchona Calisaya ; and that in my opinion the 

 specimen sent by Mr. Christie is a hybrid, apparently between 

 C. Calisaya and C. officinalis, and that the one I received from 

 Mr. Howard approaches more nearly in appearance to the Cali- 

 saya type than any other, although bearing some traces of 

 hybridization with C. officinalis. 



The history of the collection and distribution of Ledger's 

 seeds also seems to support the view that the Cinchona Ledgeriana 

 now in cultivation is not one well-marked species or variety, 

 but embraces several varieties, some of which may be hybrids. 



Thus Mr. Clements Markham, in his interesting work on 

 Peruvian Bark (p. 214), distinctly states that the seeds were 

 collected from about fifty trees. It is hardly to be supposed 

 that these trees, in a district where the tree abounds, and of a 

 species so variable as Cinchona Calisaya, would all consist of 



* Some specimens were placed on the table to illustrate this point. 



