FACTORS INFLUENCING FLOWER SIZE IN NICOTIANA 363 
than in the case of corresponding inflorescences of the two Fi hybrids, 
which have a much longer growing season and which are almost 
completely sterile as compared with 12 22/07. 
3. Other Factors 
Under this heading we desire to present data which have to do 
with the differences in size between the flowers of plants the first year 
in the field and flowers on cuttings of these plants flowering in 6 inch 
pots in the greenhouse. Tables XVIa and XVI6 give a condensed 
statement of the results of these measurements. The cuttings were 
taken during October, 1912, and came into flower in the greenhouse in 
April, 1913. The flowers were measured for the most part during the 
period from April 14 to May 12, although a few flowers were measured 
on some of the plants on July 28. The plants were given ordinary 
greenhouse treatment. 
These tables bring out a rather surprising situation with reference 
to the flower size of the cuttings as compared with that of the original 
plants the first and second years. While the spread of the flowers on 
Plant 7 in 191 3 was 8.70 zb .21 mm. larger than the spread of those 
measured on Plant 7 in 191 2, on the other hand the spread of flowers 
on the three cuttings of Plant 7 lay about midway between these two 
means, and significantly different from either as shown in the last 
two columns of Table XVIa. In other words, the spread of flowers 
on the plant in the field during May 1913 and on the cuttings of this 
plant in the greenhouse on the same dates differed to the extent of 
nearly 4 mm. The length of flowers as shown in Table XVI& behaves 
differently under these same conditions. The flowers on Plant 7 in 
1 91 3 averaged only 2.29 d= .15 mm. larger than those of 191 2 while 
for the cuttings the average length of corolla was 3.71 mm. greater 
than in 1912. For the plant in the field and the cuttings in the green- 
house flowering during the same period the length of corolla averaged 
1.42 mm. greater in favor of the cuttings. We have then with refer- 
ence to corolla spread an average flower size greater in the field than 
on the cuttings in the greenhouse and the reverse condition, but not 
so marked, in the case of corolla length. 
During the past two years some 100 plants of TV. sylvestris have 
been grown in groups under somewhat different field conditions and 
under exceedingly different greenhouse conditions. Fifty plants were 
grown in 191 4 in a rather heavily manured, somewhat shaded, and 
