188 MR. C. DARWIN ON THE SEXUAL RELATIONS OF 
The last conclusion which may be deduced from the Tables, 
even from a glance at them, is that the mid-styled form differs 
from both the others in its much higher capacity for fertilization. 
Not only did the twenty-four flowers fertilized by the stamens of 
corresponding lengths, all, or all but one, yield capsules rich in 
seed; but of the other four illegitimate unions, that by the longer 
stamens of the short-styled form was highly fertile, though less 
than in the two legitimate unions, and that by the short stamens 
of the long-styled form was fertile to a considerable degree; the 
two unions with this form’s own pollen were sterile, but in dif- 
ferent degrees. So that the mid-styled form, when fertilized by 
the six kinds of pollen, evinces five different grades of fertility. 
By comparing compartments 3 and 6 in Table II. we learn a re- 
markable fact, namely, that though the pollen from the short 
stamens of the long-styled and from this form’s own (mid-styled) 
short stamens, used in these two unions, isidentical in all respects, 
yet that its action is widely different; in the one case above half 
the fertilized flowers yielded capsules containing a fair number of 
seed; in the other case not one single capsule was produced. So, 
again, the green, large-grained pollen from the long stamens of 
the short-styled and from this form’s own (mid-styled) long sta- 
mens is identical in all respects, but its action,as may be seen in 
compartments 4 and 5, is widely different. In both these cases 
the difference in action is so plain that it cannot be mistaken, but 
it can be corroborated. If we look to Table IIL, to the legiti- 
mate action of the short stamens of the long- and mid-styled 
forms on the pistil of the short-styled form, we again see a similar 
but slighter difference, the pollen of the short stamens of the 
mid-styled form yielding a smaller average of seed during the 
two years of 1862 and 1863 than that from the short stamens of 
the long-styled form. Again, if we look to Table I., to the legi- 
timate action of the green pollen of the two sets of long stamens, 
we shall find exactly the same result, viz. that the pollen of the 
long stamens of the mid-styled form yielded during both years 
fewer seeds than that from the long stamens from the short-styled 
form. Hence it is certain that the two kinds of pollen produced 
by the mid-styled form are less potent than the similar pollens 
produced by the corresponding stamens of the two other forms. 
When we see that the capsules of the mid-styled form yield 
a considerably larger average number of seed than those of 
the other two forms,—when we see how surely the flowers are 
fertilized in the legitimate unions, and how much more productive 
