382 
MR. W. A. NICHOLSON ON RANUNCULUS FICARIA. 
most pronounced in the 3-sepal group with 1262 flowers, with 
8-petals, out of a total of 1828. An examination of the modes in 
the three groups shows that as the sepals increase the petals 
decrease. Thus, the modes are : — 3 sepals, 8 petals ; 4 sepals, 
7 petals; 5 sepals, 6 petals, he., in each case 11 perianth-leaves. 
In Table II. the flowers are grouped according to number of 
perianth-leaves only. 
TABLE II. 
Nos. 
Perianth- 
leaves. 
3 
8 
27 
9 
235 
10 
1369 
11 
319 
12 
103 
13 
41 
14 
11 
15 
7 
16 
1 
17 
2116 
Total. 
The average number of Sepals ... 3.168 
,, ,, Petals ... 8.036 
The Standard Deviation from the mean worked out by the 
method recommended by Professor Pearson (‘ Grammar of Science,’ 
2nd ed. p. 387) is, for Sepals, - 4776 ; for Petals, ‘9538. This may 
he taken as an approximate measure of the amount of variation 
from the mean. 
The calculations for the Standard Deviations have been 
kindly verified for me by Mr. H. I. Whitty, M.A., and 
Mr. J. H. Gwillim, M.A. 
