A. B. Stout 119 



the /i were continued into the /j. Series 10-8-37 and 10-8-1 Jfi 

 especially were of vigorous growth. Fifty of the 56 plants of series 

 10-8-37 were 6 or more feet tall and a few were 7 feet tall. The 

 majority of the plants of 10-8-1 Jfi were from 5^ to 6^ feet tall. (See 

 Plate IV at right with field label 26.) In these series were the largest, 

 tallest and most vigorous plants that have thus far been grown in my 

 cultures. The plants of series 10-8-173 were of somewhat smaller 

 stature. 



The three series of the I^, of the family 12-11- were remarkably 

 uniform in habit of growth as is well shown in Plate IV. The height 

 scarcely varied more than 6 inches. Some plants in each series began 

 blooming in June and were about 10-15 days earlier in blooming than 

 plants of the family 10-8- . 



Line breeding with self-fertilization for two generations has thus led 

 to the isolation of families or lines differing in general vegetative vigour. 



One line continued to the /g exhibited a decided degeneracy which 

 became more marked in the /g than in the Ii. There may be some 

 question as to whether this was due to some heritable factor of con- 

 stitutional organization such for example as extreme conditions of 

 fasciation, or whether a relation in sexual reproduction is operating 

 as an immediate cause, as it appears to be in many degenerate hybrids 

 and in the quite similar degeneratory offspring of certain illegitimate 

 and weakly compatible matings reported in Lythram Salicaria (Darwin 

 1869, 1877). 



Two main lines maintained in both the /j and the /a a high degree 

 of vegetative vigour and potential sex vigour, and one of these has 

 seemed to gain in vegetative vigour over that of the parent stock. The 

 uniformity of these differences here suggests that constitutional and 

 heritable "factors" for size are present, and are not perceptibly influenced 

 by such variations in self-compatibility as may have occurred in the 

 rather highly self-compatible parents. 



The readiness with which self-fertilized lines from parentage of high 

 self-compatibility maintain a high degree of vegetative vigour is con- 

 vincing evidence that self-fertilization is of itself not directly injurious 

 and productive of degeneracy. 



