38 FERTILITY OF VARIETIES [Chap. IX. 



Girou de Buzareingues crossed three varieties of 

 gourd, which like the maize has separated sexes, and he 

 asserts that their mutual fertilisation is by so much the 

 less easy as their differences are greater. How far these 

 experiments may be trusted, I know not ; but the forms 

 experimented on are ranked by Sageret, who mainly 

 founds his classification by the test of infertility, as 

 varieties, and Naudin has come to the same conclusion. 



The following case is far more remarkable, and seems 

 at first incredible ; but it is the result of an astonisMng 

 number of experiments made during many years on 

 nine species of Verbascum, by so good an observer and 

 so hostile a witness as Gartner : namely that the yellow 

 and white varieties when crossed produce less seed than 

 the similarly coloured varieties of the same species. 

 Moreover, he asserts that, when yellow and white 

 varieties of one species are crossed with yellow and 

 white varieties of a distinct species, more seed is 

 produced by the crosses between the similarly coloured 

 flowers, than between those which are differently 

 coloured. Mr. Scott also has experimented on the 

 species and varieties of Verbascum; and although 

 unable to confirm Gartner's results on the crossino; of 

 the distinct species, he finds that the dissimilarly 

 coloured varieties of the same species yield fewer seeds, 

 in the proportion of 86 to 100, than the similarly 

 coloured varieties. Yet these varieties differ in no 

 respect except in the colour of their flowers ; and one 

 variety can sometimes be raised from the seed of another. 



Kolreuter, whose accuracy has been confirmed by 

 every subsequent observer, has proved the remarkable 

 fact, that one particular variety of the common tobacco 

 was more fertile than the other varieties, when crossed 



