b HORTICULTURAL SOCIETY OF NEW YORK. 



which was to see a mixture of true long grains and true round grains, for all 

 the pollen of these plants was typically long, showing dominance of the long 

 pollen as a plant character. 



I know no example of the production of an atavistic heterozygote so 

 curious as this. It should be stated that white color of flowers is, in general, a 

 pure recessive character in sweet peas. Hence, had I happened to cross a 

 long and a round pollened Henderson together without knowing of this pollen 

 difference, I should not have been aware of the heterozygous nature of the 

 purple mongrel, and should have been still more hopelessly unable to bring the 

 facts into line. Even as it stands, we may feel fairly sure that something more 

 than simple Mendelian phenomena are presented by this case, but pending the 

 next generation we cannot analyze it any further. 



The occurrence of these heterozygous forms concerns the practical breeder 

 very closely. The breeder may breed a new variety of value, and he may be 

 most anxious to obtain its seed pure. Year by year he selects it, but every year, 

 if it be a heterozygote, it fails to come true; because, as we now see, its germ 

 cells do not transmit or represent the heterozygous character, but merely the 

 pure characters of its components. 



In the garden of my friend, Mr. Sutton, of Reading, I have seen a case 

 of this kind. It is a beautiful Chinese Primrose (Primula sinensis) of a 

 curious lavender color. The seeds of the self-fertilized lavenders are sown 

 each year, but of the total offspring only about half are lavenders, one-quarter 

 being a tinged white and one-quarter magentas. We can scarcely doubt that 

 the lavenders are formed as the heterozygote of that particular white and ma- 

 genta, the whites being homozygotes formed by the union of two white 

 gametes, while the magentas are similarly formed by the union of two magenta 

 gametes. In such a case statistical study of the offspring will show the 

 breeder with approximate certainty what he is dealing with, and will give him 

 a good indication whether it is w^orth wdiile for him to continue in his attempt 

 to get the variety true. 



A case almost certainly of the same nature occurs in poultry — the case of 

 tlie Andalusian fow'l. The Andalusian was at one time a favorite breed. Its 

 plumage is of a peculiar blue-gray, mixed with black. You may go to the 

 poultry shows and buy the winning Andalusians, thinking that they will breed 

 true. But they will not. Andalusians have been bred for at least forty or fifty 

 years, and there is no good reason for thinking that they breed any truer now 

 than formerly. Every one is agreed that the breed possesses this drawback. 

 The "impurity" manifests itself in the production of numerous black birds and 

 numerous white birds irregularly splashed w'ith blackish gray. From such 

 evidence as I can obtain it seems almost certain that these tW'O objectionable 

 forms are produced in about equal numbers, and that the number of true 

 Andalusians is about double the number of either. The Andalusian is almost 

 unquestionably a heterozygous form made by the union of the black gamete 

 with the white-splashed gamete. It is, moreover, on record that the two sport- 

 forms crossed together produce only Andalusians, as they should do if the 

 case is a simple Mendelian one. We may, therefore, predict that the Anda- 

 lusian, like the lavender Primula, will nczrr breed true, however well or long 

 it be selected. 



