222 CAUSES OF VARIATION 



American seed growers generally seem to have settled upon 

 Kansas as the spot most favorable to the development of the 

 highest quality in the watermelon, and it is accordingly the 

 favorite seed-producing locality. Darwin tells us that " the seed 

 of the Persian melon yields near Paris a fruit inferior to the 

 poorest market kinds, but at Bordeaux yields delicious fruit." : 



European varieties of grapes failed so utterly in eastern North 

 America as to necessitate the developing of varieties from the 

 native vine. 



Indian corn develops local varieties with extreme readiness, 

 but they seldom succeed when transferred even short distances, 

 at least until time enough for acclimatization has elapsed. The 

 writer sent a standard white Illinois corn, ripening in about a hun- 

 dred and twenty days and capable of maximum yields (seventy-five 

 bushels per acre), to be grown in Michigan, Wisconsin, Maine, and 

 Mississippi. 2 In Maine it failed to ripen, but at all other points 

 it ripened in about a hundred days, producing small, inferior 

 ears, altogether worthless as a commercial crop. That it should 

 hurry through its period of growth at the north was not surpris- 

 ing, but that it should do the same at the south, where it had 

 even more time at its disposal than at home, is unaccountable. 



Wheat, on the other hand, is a cosmopolitan crop, and while 

 varieties succeed better in some localities than in others, yet a 

 new variety seldom fails, and sometimes succeeds even better 

 than in the locality whence it came. However, it is altogether 

 likely that no known wheat-growing region equals England in 

 natural advantages for maximum yields. This is supposed to be 

 due to the humid atmosphere and cloudy skies during the later 

 stages of growth, in sharp contrast to the bright skies and hot 

 dry air of America at this season. If this be the true partial 

 explanation of the occasional phenomenal and always high yields 

 in Great Britain, 3 we may hope for equal results some day in the 

 similar climate of Oregon. 



1 Darwin, Animals and Plants, II, 264. 



2 Wisconsin, 200 miles north; Michigan, 200 miles north and 100 miles east; 

 Maine, 300 miles north and 900 miles east ; Mississippi, 450 miles south. 



8 The average wheat yield of the United States is between 12 and 13 bushels 

 per acre, while that of Great Britain is almost exactly 30, and a maximum of 90 

 bushels has been reported. 



