INDEPENDENT MENDELIAN INHERITANCE 79 
of these observations, particularly with respect to that pair of characters 
concerned with cotyledon color. Johannsen has summarized these 
results and examined them with reference to their agreement with the 
conditions imposed by the laws of chance. Table VIII which has been 
adapted from Johannsen shows that in a sum total of 179,399 counts 
by seven different investigators the ratio was 3.0035:0.9965. The 
probable error for this number of observations is + 0.0028 so that the 
deviation from the ideal ratio is slightly greater than the probable error, 
but only so great that such a deviation would be expected approximately 
twice in five times. 
Another case which has been investigated with very large numbers 
is that of the contrasted characters starchy and sweet endosperm in 
Fic. 37.—Results of crossing starchy and sweet corn: a, Sweet parent; c, starchy parent; 
b, the F: showing complete dominance of starchiness; d, the Fz: showing monohybrid 
segregation; e, f, g, and h, Fs: populations, the last three obtained by planting F2 starchy 
grains, the sweet ear, e, by planting an Fz sweet grain. (After Hast and Hayes.) 
maize. Those varieties of maize which have starchy endosperms have 
smooth opaque grains whereas the varieties with sweet endosperms have 
translucent, wrinkled grains. The difference is due to the fact that in 
ripening there is a progressive formation of starch in starchy races, but 
in sweet races the starch grains formed are small and angular and there 
is an actual breaking down. of endosperm materials into various kinds 
of sugars. Correns has shown that starchiness is completely dominant 
and segregation is sharp and unquestionable aside from very exceptional 
cases of intergrading. Fig. 37 illustrates very well how sharply segre- 
gation occurs in hybrid ears. The results of Hast and Hayes’ extensive 
investigations of segregation for this pair of characters are summarized 
in Table IX. In this table families have been entered separately so that 
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