334 
PROEESSOR K. PEARSOX AXD OTHERS OX 
ISngiish Onion. 
Xumber of 
Mean Xo. 
of veins. 
S. D. 
Coefficient 
of 
variation. 
S. D. of 
arra}". 
Percentage 
variation. 
Correia- ' 
tion. 
1 
Plants. 
Tunics. 
Pairs. 
200 
1085 
4924 
29-8725 
± -1066 
5•2060 
± -0754 
17-4274 
4-1222 
79-18 
-6108 
[± -0128] 
The actual number of tunics with veins countable was made up as follows; 
121 onions with 6, 44 with 5, 34 with 4, and 1 with only 3 available tunics. It will be 
seen that the onion has a degree of resemblance in its undifferentiated-like organs 
closely resembling that of the Chelsea Shirley poppies, of the Dorsetshire hollies 
(without No. 91), or the mixed Spanish chestnuts, and somewhat less than that found 
for the two series of ferns. Its variability approaches closely that of the wild poppy. 
On the whole it fits well into our series of results, the somewhat high value of the 
correlation approaching those of several sets, the homogeneity of which is not entirely 
above suspicion. The accompanying table gives the classified data from which the 
constants were deduced. 
Section VI .—Leguminous Plants. 
(20.) I had at an early stage considered that the counting of seeds in the pods of 
leguminous jDlants would be a very easy manner of testing the intensity of homo- 
typic correlation. But as the number of seeds fully developed would depend on 
the extent to which the flower had been fertilised, it seemed to me, after further 
thinking a])out the problem, that unless I counted all the abortive as well as the fully 
developed seeds, I should find the factor of homotyposis weakened by the external 
chances upon which I thought cross-fertilisation must depend, and which I feared would 
have nothing in the main to do with the individuality of the plant. I made some 
attempts to count all abortive as well as fully developed seeds in certain species, but I 
found the task not only very laborious, but my estimates doubtful. Examining for 
another purpose Darwin’s ‘ Cross- and Self-Fertilisation of Plants.’ I was struck by 
the fact that he did not hesitate for the purpose of comparing their vigour to count 
the seeds of plants living in the open and all alike subject to free visitation from 
insects and bees. He distinctly states (3rd Edn., p. 115) that “the difierence in the 
number of the contained seeds'^ must depend upon the constitution of the plants.” 
This view of the matter impressed me without entirely removing my earlier doubts. 
Given a number of plants living under the like conditions, and with a superabundant 
visitation from insects, there would be ample and equal chance of fertilisation for all 
* Darwin in all cases appears to have calculated the good or fully developed seed. 
