A. B. Stour * 109 
shifting bags, and tagging heads. Bags need to remain enclosing a 
group of branches for only 24 hours. By beginning on the first or second 
day of bloom and shifting a bag about three times, about 30 flower heads 
per plant can readily be selfed during the first ten days of bloom. 
The I, generation. 
Tests for self-compatibility were made for 351 plants of the J, genera- 
tion which were grown from the self-fertilized seed of 3 self-compatible 
plants. The presentation of data for all these plants would involve rather 
extended tables, hence complete data will here be given only for certain 
self-compatible plants which are fully representative of the results 
obtained, and illustrate the range in the percentages of self-compatibility. 
In the following tables dates of pollination and number of seed per head 
are given. The period of ‘bloom is given for the Z,, but for the J, the 
last dates of blooming were not recorded. The percentage fertility for 
all plants of the J, and J, is based on the proportion of flowers (estimated 
at 20 per head) which produced seeds, and the percentages for the few . 
self-fertile plants obtained previously are here also thus. determined. 
A general summary showing distribution according to the degrees of 
self-fertility is given in Table IV (p. 115). 
Series R 12-11- . The immediate parent of this series was one of 
evidently high self-fertility (1917, Table I). It was, howéver, the only 
one of 18 sister plants which was found to be self-compatible. Of this 
Series 35 plants were self-incompatible and 26 were self-compatible. 
Data for 8 of the latter are given in Table I (p. 110). 
Series R 10-8— . The 177 plants of this series were grown from the 
selfed seed of a plant (R 10, no. 8) whose*self-compatibility is here esti- 
mated at 55°/,. This plant was the only one of 10 sisters to set seed 
to selfing. Of the series, 128 plants were completely self-incompatible 
and 49 were self-compatible. The fertilities ranged to 42 °/,. 
Series R 9-34- . The immediate parent (R 9, no. 34) was one of 
25 sister plants three of which were self-compatible. Controlled self- 
pollinations were made on 113 of the progeny: 81 were self-sterile and 
32 were self-fertile with fertilities ranging to 43°/,. In this series there 
were also 40 plants which were highly impotent, a condition discussed later. 
The I, generation. ; 
The number of plants tested for self-compatibility in this generation 
was 471. The number of flower heads tagged for autonomous selfing 
was 14,390; the average per plant was 30 flower heads or about 200 
