FACTORS INFLUENCING FLOWER SIZE IN NICOTIANA 353 
the Spread of flowers on Plant 15 had decreased in size only 0.75 mm. 
Nearly a month later the corolla spread of Plant 15 had decreased 
2.29 mm. while on Plant i, which also was measured on September 22, 
Fig. I. Influence of removal of flowers on plants 13 22/07. 
the decrease in spread was 540 mm. A somewhat corresponding 
situation holds for the length of corolla. Thus on Plant 14 the decrease 
in length was 4.55 mm. and on Plant 15 it was only 0.25 mm. Nearly 
a month later the decrease in the case of Plant 15 was 0.79 mm. and 
that of Plant i was 4.00 mm. Plant 15 continued to flower until the 
middle of December by which time the other 74 plants of 13 22/07 
had been dead for over two months. 
Figure 2 represents two F2 plants of H103 which is a hybrid between 
two flower size varieties of N. acuminata (cf. Goodspeed, 19 12). 
Tables Xa and X& give the distribution of spread and length of corolla 
for Plants 13 and 14 of this hybrid, 13 F2 H103 P2. As will be seen these 
