Oct., 1923] 
STOUT-STUDIES OF LYTHRUM SALICARIA 
445 
during the first 18 days of bloom. The plant was in bloom 55 days. The 
results obtained for selfing are summarized in table 1 and are shown in more 
detail in table 2, in which, to facilitate ready comparison, the data are 
compiled for three periods. 
Table 2. Record for controlled pollinations of mid-styled plant no. 1 in summer of 1919 
1st to 18th Day 
19th to 36th Day 
37th to 55th Day 
Selfed with pollen of long 
stamens 
Failures—no pods. 
70 
35 
9 
Pods produced. 
18 
46 
70 
Seeds per pod—range and 
average. 
(0 to 117) av. 34 
(2 to 81) av. 32 
(3 to 82) av. 32 
Selfed with pollen of short 
stamens 
Failures. 
33 
57 
47 
Pods. 
1 
1 
1 
Seeds per pod. 
37 
10 
1 
Legitimate cross-pollination 
Failures. 
Pods. 
Seed-range and average. . 
2 
20 
(12 to 176) av. 98 
Of the 140 flowers hand-pollinated with poilen from short stamens, only 
three produced pods yielding 1, 10, and 37 seeds respectively, but these 
may have been due to chance pollination with pollen from the long stamens 
at the time of their removal or with pollen of other flowers which were 
enclosed in the same bag. The results indicate that the plant remained 
decidedly if not completely self-incompatible to pollen of its own short 
stamens throughout the entire period of bloom. 
When pollen of long stamens was used in hand-pollinations, the propor¬ 
tion of pods produced increased as the season advanced, and during the 
last 18 days of bloom there were but 9 failures out of 79 flowers pollinated. 
The results show conclusively that the self-compatibility in this plant 
involves fertilizations from the pollen of long stamens, and also that this 
compatibility actually increases toward the end of the period of bloom. 
The increase in compatibility affects, however, the number of pods that are 
formed rather than the number of seeds in a pod. The average number of 
seeds in the pods that were produced was almost the same for all periods, 
but the highest number of seeds in any pod was obtained during the first 
18 days of bloom. 
The 22 legitimate crosses made during the first 18 days gave 20 pods 
with seeds ranging in number from 12 to 176, with an average of 98 seeds 
per capsule. These results show conclusively, as do those of open cross¬ 
pollinations during the early part of the period of bloom in the previous 
year, that the pistils of the plant are highly potent during the period of 
marked self-incompatibility. The decided change in fruit-production s 
33 
