CHAPTER II. 



METHODS FOR DISCOVERING OR PROVING THE ORIGIN OF 



SPECIES, 



1. General reflections. As most cultivated plants have 

 been under culture from an early period, and the manner 

 of their introduction into cultivation is often little known, 

 different means are necessary in order to ascertain their 

 origin. For each species w^e need a research similar to 

 those made by historians and archaeologists a varied 

 research, in which sometimes one process is employed, 

 sometimes another ; and these are afterw^ards combined 

 and estimated according to their relative value. The 

 naturalist is here no longer in his ordinary domain of 

 observation and description; he must support himself 

 by historical proof, which is never demanded in the 

 laboratory; and botanical facts are required, not with 

 respect to the physiology of plants a favourite study of 

 the present day but with regard to the distinction of 

 species and their geographical distribution. 



I shall, therefore, have to make use of methods of 

 which some are foreign to naturalists, others to persons 

 versed in historical learning. I shall say a few words 

 of each, to explain how they should be employed and 

 what is their value. 



2. Botany. One of the most direct means of dis- 

 covering the geographical origin of a cultivated species, 

 is to seek in what country it grows spontaneously, and 

 without the help of man. The question appears at the 

 first glance to be a simple one. It seems, indeed, that 



