126 Mr. A. D. Darbishire. On Crossing Round wth {June 20, 
singleness and the degree of compoundness in the grains of wrinkled peas. 
For whilst in these latter the number of pieces varies between 2 and 8 
and the commonest is 6, in the F, grain it varies between 2 and 4 and the 
commonest is 3. 
Table I gives the average length, breadth, and length-breadth index of 
166 7-grains, side by side with the measurements for p- and c-grains for 
comparison. 
Table I. 
Round. | 1p - Wrinkled. 
p-grain. r-grain. ce-grain. 
Average length ...........c00ce0s 0 :0322 0 :0276 00269 
Average breadth ..............0008 0 02138 0 0236 0 0248 
Length-breadth index ......... 66 *14 85 °5 92°19 | 
This table shows that, in the matter of shape, the F, grain is intermediate 
between the p- and the c-grain, but nearer the c-grain. | 
The Starch-grains in a Subsequent Generation. 
I have not at present any information as to the nature of the grains in Fs, 
but I have some data relating to F; which throw much light on the mode of 
segregation in this case. 
By a fortunate chance I happened, when I turned my attention to this 
subject, not to have sown the contents of 48 packets of F; peas;* each 
separate packet of which contained five seeds from a single plant. Thirty-six 
of the packets contained round seeds; 12 of them contained wrinkled ones. 
I possessed a record of the number of green and yellow, as well as, what 
concerns us now, the number of round and wrinkled seeds produced by each 
* The history of these seeds is as follows: In the spring of 1905, Mr. C. C. Hurst 
kindly gave me the seeds borne on an F; plant from a cross which he had made between 
“British Queen ” (yellow wrinkled) and “ Eclipse” (green round) (‘ Journ. R. Hort. Soe.,’ 
vol. 28, pp. 3 and 4). These seeds included yellow rounds (Y R), yellow wrinkled (Y W), 
green rounds (G R), and green wrinkleds(G W). I sowed these four sorts separately. The 
Y R’s gave either (i) plants bearing only Y R’s, or (ii) plants bearing Y R’s and Y W’s, 
or (iii) plants bearing Y R’s and G R’s, or lastly (iv) plants bearing Y R’s, Y W’s, G R's, 
and G W’s. The total number of yellow seeds, round and wrinkled, borne by plants 
falling in the last category (iv) was 232. These were sown, and 196 of them produced 
mature plants. 10 seeds from each of the 196 plants thus raised were preserved, in 
2 packets of 5 from each plant. All of these seeds were sown this spring, except the 
contents of the 48 packets referred to in the text. 
Sa) ee 
