AUTHORS PREFACE. Vll 



spontaneous, that is, wild condition, or at any rate this 

 condition is not proved. Questions of this nature are 

 subtle. They, like the distinction of species, require 

 much research in books and in herbaria. I have even 

 been obliged to appeal to the courtesy of travellers oi- 

 botanists in all parts of the world to obtain recent 

 information. I shall mention these in each case with 

 the expression of my grateful thanks. 



In spite of these records, and of all my researches, 

 there still remain several species which are unknown 

 wild. In the cases where these come from regions 

 not completely explored by botanists, or where they 

 belong to genera as yet insufficiently studied, there is 

 hope that the wild plant may be one day discovered. 

 But this hope is fallacious in the case of well-known 

 species and countries. We are here led to form one of two 

 hypotheses ; either these plants have since history began 

 so changed in form in their wild as well as in their 

 cultivated condition that they are no longer recognized 

 as belonging to the same species, or they are extinct 

 species. The lentil, the chick-pea, probably no longer 

 exist in nature ; and other species, as wheat, maize, the 

 broad bean, carthamine, very rarely found wild, appear 

 to be in course of extinction. The number of cultivated 

 plants with which I am here concerned being two hun- 

 dred and forty-nine, the three, four, or five species, extinct 

 or nearly extinct, is a large proportion, representing a 

 thousand species, out of the whole number of phane- 

 rogams. This destruction of forms must have taken 



