352 
T. H. GOODSPEED AND R. E. CLAUSEN 
with the number taken in 1913. The first set of measurements was, 
however, taken with unusual care, since it was in both cases desired 
to measure all the plants on the same day, and since it was recognized 
at the time that to do so only a few measurements could be taken. 
When the measurements were made the terminal inflorescences were 
practically out of flower and only the largest flowers and those shed- 
ding pollen, on the flowering laterals were measured. The method of 
taking measurements in 1913 has already been described. 
In Tables Villa, VIII&, IXa, and IX& are given the distribution 
for individual plants of Fi H^s and Fi H44 in 191 2 and the same plants 
cut back and flowering in 1913. In the last column is given the 
differences between the means and the probable errors of these 
differences. 
As a third consideration under the general heading "age of plant 
factor," we have data bearing on the influence on flower size of the 
presence of developing seed capsules following the earlier flowers of the 
plant. In the earlier experiments on the inheritance of flower size in 
Nicotiana (cf. Goodpseed, 1912) the effort was made to measure every 
fully developed flower each day on all the plants under consideration. 
In such a case there are at the end of the period of measurement no 
developing or matured seed capsules on the plant. It was early 
observed that when these plants, from which all the flowers had been 
picked off for a month or more, were allowed to make seed normally 
the flowers they bore among the developing seed capsules were dis- 
tinctly smaller than those previously measured. When this particular 
point was investigated in 191 3, the observations previously made were 
strikingly confirmed and the distinct relation between the longevity of 
the plant and the amount of seed allowed to mature was further 
evidenced. 
Figures I and 2 bear out the above statement without room for 
doubt or question. Figure i shows two plants of 13 22/07; Plant 14 on 
the right and Plant 15 on the left in the photograph. The photograph 
was taken 2 weeks after the last measurement on Plant 15. In the 
case of Plant 15 the flowers too old to be measured and developing 
seed capsules were picked off twice a week, while from Plant 14 only 
the 42 flowers measured were removed. Every fully developed flower 
present on Plant 15 on each of the dates of measurement was measured. 
In a month the spread of corolla of flowers on Plant 14 dropped from 
27.38 mm. to 21.60 mm., or 5.78 mm., while during a similar period 
