304 FERTILITY OF VARIETIES 



species. The evidence is also derived from hostile wit- 

 nesses, who in all other ca=es consider fertility and sterility 

 as safe criterions of specific distinction. Gartner kept, 

 during several years, a dwarf kind of maize with yellow 

 seeds, and a tall variety with red seeds growing near each 

 other in his garden; and although these plants have sepa- 

 ated sexes, they never naturally crossed. He then fertil- 

 ized thirteen flowers of the one kind with pollen of the 

 other; but only a single head produced any seed, and this 

 one head produced only five grains. Manipulation in this 

 case could not have been injurious, as the plants have sepa- 

 rated sexes. N"o one, I believe, has suspected that these 

 varieties of maize are distinct species; and it is important 

 to notice that the hybrid plants thus raised were them- 

 selves j9er/ec% fertile; so that even Gartner did not ven- 

 ture to consider the two varieties as specifically distinct. 



Girou de Buzareingues ci-ossed three varieties of gourd, 

 which like the maize has separate sexes, and he asserts that 

 their mutual fertilization 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 classifi- 

 cation by the test of infertility, as varieties, and N"audin 

 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 astonishing num- 

 ber of experiments made during many years on nine species 

 of Verbascum, by so good an observer and so hostile a wit- 

 ness as Gartner: namely, that the yellow and white varie- 

 ties when crossed produce less seed than the similarly 

 colored 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 colored flowers, than between those which are dif- 

 ferently colored. Mr. Scott also has experimented on the 

 species and varieties of Verbascum; and although unable 

 to confirm Gartner's results on the crossing of the distinct 

 species, he finds that the dissimilarly colored varieties of 

 the same species yield fewer seeds, in the proportion of 

 eighty-six to 100, than the similarly colored varieties. Yet 

 these varieties differ in no respect, except in the color of 



