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AMERICAN JOURNAL OF BOTANY 
[Vol. io, 
hence due to a change in the physiological relations between pistils and the 
pollen of long stamens. Pollen from both short stamens and long stamens 
was examined at frequent intervals throughout the entire period of bloom; 
there was very little abortion, the pollen was successfully germinated in 
artificial media, and the use of such pollen in legitimate crosses on several 
dates during the first 30 days of bloom was almost invariably highly effective 
in pod- and seed-production. There were in this plant no noticeable 
evidences of impotence of stamens and anthers, such as are to be seen in 
some plants of this species. 
The branches left to open-pollination produced pods quite as in the year 
1917. Several of the main branches were selected and divided into thirds, 
and seeds in all pods in the lower two thirds were counted; then an equal 
number of pods from the many pods in the uppermost third were taken at 
random for counts, the entire number, 142, being as near the number of 
pods secured from the selling by hand in which the pollen of long stamens 
was used as was possible. As shown in table 1, the range for number of 
seeds per pod and the average were higher for the lower two thirds than in 
the last 'third, showing that the change in compatibility involves number of 
pods formed rather than number of seeds per pod. Comparison shows that 
the controlled pollinations in which pollen from long stamens was used were 
somewhat more successful than free open-pollinations, when judged by the 
average number of seeds produced. 
A third mid-styled plant (M no. 3) was grown in isolation in the New 
York Botanical Garden at a distance of about one mile from the location of 
the plant M no. 1. This plant proved to be decidedly less self-compatible to 
open self-pollination than were M no. 1 and M no. 2, but, as in M no. 2, 
there was quite the same proportion of pods produced throughout the entire 
season of bloom, no change in compatibility being evident as observed in 
the plant M no. 1. 
Summary. In these tests seeds were obtained to illegitimate self- 
pollination of plants of all three forms. Mid-styled plants were most 
highly self-compatible in respect to the number of pods produced. The 
pods found were distributed irregularly over the entire period of bloom 
except for one plant (M no. 1), in which it was found that there was an actual 
change in the degree of self-compatibility to pollen from its own stamens. 
The results from year to year have been very uniform for all plants, except 
for the plant S no. 2. Its feeble production of pods in 1918, followed by 
the production of 161 pods in 1919, suggests that the plant is rather strongly 
self-compatible provided insects make the proper pollinations. It may 
readily be conceded that the kinds of insects that can most efficiently self- 
pollinate long-styled and mid-styled plants are not the ones which best self 
the short-styled plants. 
Self-pollination does not appear to be uniformly as efficient in seed- 
production as are certain legitimate cross-pollinations, at least for the one 
