tilized lines of as nearly equivalent parentage as possible. Al- 

 though a study of the injurious effects of self-fertilization was not 

 the aim of the investigation, it was immediately apparent in the 

 smaller, weaker stalks, fewer and smaller ears, and the much greater 

 susceptibility to the attacks of the corn-smut (Ustilago maydis}. 

 These results were almost as marked when the chosen parents were 

 above the average quality as when they were below it, which in 

 itself refutes the idea that the injurious effect is due to the accu- 

 mulation of deficiencies possessed by the chosen parents. 



All the cross-bred rows were similar in structure, vigor, varia- 

 bility, etc., but each self-fertilized row could be seen to differ from 

 other self-fertilized rows in ways capable of description in fairly 

 definite terms. Without entering into a description of all the different 

 self-fertilized rows, a comparison between the two rows showing 

 the greatest contrast will suffice to illustrate and serve as a basis 

 for the conclusion to be arrived at. Following the method every- 

 where known among breeders as the "ear-row test," I planted 

 parallel rows from ears having given numbers of rows of grains, 

 one self-fertilized and one cross-fertilized ear form each row-class, 

 i. e., one row was planted from a self-fertilized ear and beside it a 

 row from a cross-fertilized ear having 10 rows of grains each; one 

 row each was planted from two ears having 12 rows of grains; 

 and so on. 



Taking for comparison the row produced from a self-fertilized 

 ear having 12 rows of grains, and the row produced from a self- 

 fertilized ear having 14 rows of grains, the following differences 

 were observed. In each row the variability was slight and the 

 different qualities noted were characteristic of the entire row. 

 The characters are given in contrasted pairs (designated as a and 

 b), the qualities of the row originating from a 12-rowed ear (a) 

 being given first in each pair: (a) Average height, 6}^ feet, (b) 

 average height, 8^ feet; (a) stalks moderately stocky, (b) stalks 

 slender; (a) strong tendency to sucker near the ground, (b) no 

 suckers; (a) leaves broad, dark green, and spreading, (b) leaves 

 rather narrow, light green, not strongly spreading; (a) ears 

 rather strongly diverging on long shanks, the latter usually as long 

 as the internodes or longer, (b) ears erect on short shanks which 

 are usually not over half the length of the internode; (a) husks 

 with well-marked leafy appendages, (b) husks without appen- 

 dages; (a) grains flinty, (b) grains starchy; (a) most common num- 

 ber of rows to the ear, 10 ; (b) most common number of rows, 14. 



Most of the features here contrasted differ more or less in both 

 cases from the cross-fertilized rows derived from the same original 

 stock. If self-fertilization is assumed to be the direct cause of any 

 of the above characteristics of the one row, it is obviously illogical 

 to attribute the opposite characteristic possessed by the other row 

 to self-fertilization as a direct result. We come to" the conclusion 

 therefore that the observed differences between these rows are not 



