408 
Cooperative Investigations on Plants 
be carried out, and there is little doubt that it is not only a feature much modified 
by season and environment but even by the interval between opening of the bud 
and the time of record. 
The following table gives our results : 
Parkstoiie General Parkstoiie Mothers Crewe General 
Population of Crewe Crop Population 
Frilled and Wrinkled ... 70 12 137 
Slight Wrinkling ... 346 112 234 
No Wrinkling ... 553 275 28 
969 399 399 
Or, as percentages : 
Frilled and Wrinkled ... 7-2 3-0 34-3 
Slight Wrinkling ... 35-7 28-1 58-7 
No Wrinkling ... 57-1 68-9 7-0 
Now it will be clear that while the maternal plants of the Crevve crop are a 
selected group of the Parkstone crop, yet there is no relation between the per- 
centages in these mothers and in the offspring. The 70 per cent, of not wrinkled 
maternal plants actually produced four times as many wrinkled and eight times as 
many slightly wrinkled as not wrinkled plants, and the 3 per cent, wrinkled 
produced twice as many not wrinkled and slightly wrinkled as wrinkled plants !* 
In fact while the Parkstone crop had more non-wrinkled poppies than any other 
and the maternal selection 12 per cent, more than the general Parkstone popula- 
tion, the Crewe offspring had only 7'0 per cent, of non-wrinkled poppies, less than 
half that shown by the most wrinkled crop, Arncliffe, which showed about 15 per 
cent. Whatever changes took place in environment and season between Parkstone 
and Crewe they were sufficient to totally upset wrinkling as an inherited character! 
Some possibly, but far from all, of this difference we believe may be due to personal 
equation. The main feature to be noticed is that whereas the southern crops, 
Parkstone and Streatham, have more than 45 per cent, of unwrinkled flowers, the 
northern crops have less than 17 per cent. (Arncliffe 14'9, Kidderminster 16'4), 
sinking to 7 per cent, at Crewe. 
If we confine our attention to the Parkstone crop and take d for the range of 
slightly wrinkled we have : 
d = 1-3860 X 0-' = 1-2812 0-, 
Or the stringency of maternal selection 
= /A = (77(7 = -9244. 
If we take the Oxford crop of 1900 as one in which the wrinkling was very 
carefully observed, we find d = 1-1946 cr, or we have /x = o-7<7 = -8620 ; so that it is 
quite possible that the stringency may be greater than that indicated by the 
Parkstone crop. 
* See Appendix I., Table F. 
