THE THREE FORMS OF LYTHRUM SALICARIA. 185 
tained (excluding one capsule with 12 seed), on an average, 117:2 
seed. 
Fifteen flowers fertilized by the longer stamens of the short- 
styled form yielded 93 per cent. of capsules, which (excluding 
four capsules with less than 20 seed) contained, on an average, 
102:8 seed. 
Thirteen flowers fertilized by the shorter stamens of the long- 
styled form yielded 54 per cent. of capsules, which capsules (ex- 
cluding one with 19 seed) contained, on an average, 60°2 seed. 
Twelve flowers fertilized by own longer stamens yielded 25 per 
cent. of capsules, which (excluding one with 9 seed) contained, on 
an average, 77:5 seed. 
Twelve flowers fertilized by own shorter stamens yielded not a 
single capsule. 
Considering the three Tables and this summary, we may safely 
draw the following conclusions. First, that, as in structure so in 
funetion, there are three females or female organs: this is mani- 
fest; for when all three receive the very same pollen, they are 
acted on most differently. So conversely with the thirty-six sta- 
mens, we know that they consist of three separate sets of a dozen 
each, differing in various respects; and in function the pollen of 
these three sets when applied to one and the same stigma acts 
most differently, as a glance at the Tables proves. But we shall 
presently see that the action of the pollen of the whole dozen 
longest and of the whole dozen shortest stamens is not identical. 
Secondly, we see that only the longest stamens fully fertilize 
the longest pistil, the middle stamens the middle pistil, and the 
shortest stamens the shortest pistil. And now we can compre- 
hend the meaning of the almost exaet correspondence in length 
between the pistil of each form and the two half-dozen sets of 
stamens borne by the two other forms; for the stigma of each 
form is thus rubbed against the same spot of the insect's body, 
which becomes most charged with the proper pollen. In all three 
forms, the female organ is but feebly, or not at all, acted on by its 
own two kinds of pollen. In my papers on the dimorphism of 
Primula and Linum, I used the terms “ heteromorphic " for the 
fully fertile unions between the female element of the one form 
and the male element of the other, and * homomorphie " for the 
less fertile or quite sterile unions between the female and male 
elements of the same form. The principle involved in these terms 
holds good with Zythrum, but is insufficient ; for though in each 
of the three forms the fertile unions are all heteromorpAic, the ap- 
