Trifoliuin Pratense Qiilnqucfolinm. 49 



tinguishcd from the ordinary instances of the rare four- 

 leaved clover. 



A glance at the table on page 38 will show that my 

 race was only very slightly developed at first, and had to 

 be brought to its normal type by isolation and selection. 

 But in spite of this selection it is not so constant that it 

 does not occasionally give rise to atavistic individuals. 

 On the other hand individuals with a maximum develop- 

 ment of the character of the race are from time to time 

 produced. And these extremes are sometimes both found 

 within the limits of a single culture. 



I observed this in 1894 with plants which had been 

 raised from the seeds of a single individual in the third 

 generation (1891, p. 38). The seed-parent in question 

 had survived the winter and did not ripen its seed until 

 the second year. In July, 1894, there was a large num- 

 ber of strong plants of the same age, of which I chose 

 the seven best for a detailed examination of their leaves. 

 Some of the oldest leaves were already withered, the 

 youngest not yet unfolded; these were not recorded. Each 

 of these seven plants was plotted in the form of a curve, 

 one (Fig. 6 A) gave the normal curve of the race, an- 

 other (B) was atavistic, whilst all the rest had their 

 highest ordinate at 7. I have only given the mean value 

 for these five (C). 



These three groups gave the following percentage 

 of leaves with the number of leaflets written above them : 



Number of leaflets: 3 4 5 6 7 Nnmbei of leaves counted 



A. Normal example: 17 16 37 14 16 172 



B. Atavistic example: 75 19 5 1 216 



C. Extreme variants: 12 9 22 17 40 97^ 



^ Mean number per plant. 



