On the Species of the Genus Primula in Essex. 165 
all of their capsules, so that I had difficulty in getting un¬ 
opened capsules, and those I did get seemed to be small, 
late, and weakly ones. Unfortunately, before I had an 
opportunity of counting their seeds the capsules of all but 
four s. and five 1. burst, mixing the seed so that I was only 
able to include them in the total weight of seeds. 
It will he seen from Table IX. that these results are not 
nearly so satisfactory as in the last species. The long-styled 
plants in this case certainly produced rather more seeds than 
the short-styled plants ; but how to account for this I do not 
know, as I am convinced from my own experiments and Mr. 
Darwin’s that the s. do, as a rule, produce the most seed, at 
least in the Primrose and Cowslip, and it is not likely that 
the opposite holds good with the Oxlip. However, all the 
capsules were taken from small and rather late plants, which 
are, I believe, not so likely to he trustworthy; and the small 
number of seeds actually counted, on account of the bursting 
of the capsules, is far from satisfactory. I shall recur to this 
matter at another time. Unfortunately I took no account of 
the flowers which set no seed, or the result would certainly have 
been different. The four highest numbers for the s. are 58, 59, 
64, and 75; and the four highest numbers for the 1. are 49, 54, 
54, and 57, the highest of the latter (57) being less by one 
than the lowest of the former; whilst the four lowest numbers 
for the s. are 3, 4, 4, and 5; and the four lowest numbers for 
the 1. are 1,1,2, and 2, the highest of the latter being less by 
one than the lowest of the former; so that by this standard 
of comparison the s. have the advantage. 22 
22 I nmst beg leave to differ from Mr. Darwin in one statement which 
he makes (p. 20), namely, that the fairest standard by which to estimate 
the relative fertility of the two forms is by the product of an equal number 
of umbels. Now it is certain that with a species like P. farinosa, which 
rarely produces more than one umbel, this would be the case; but with 
the other species of Primula (which produce an uncertain number of 
umbels) we can by this standard only estimate the fertility of the umbels , 
not of ike plants themselves (which is what we want to get at), unless we 
take account of the number of umbels which each plant produces. The 
last table is a case in point; the s. umbels are the most fertile in the pro¬ 
portion of 4 to 3, but the 1. produce almost half as many more umbels than 
the s.; so that the 1. plants produce on the whole rather the most seeds. 
