178 MR. C. DARWIN ON THE SEXUAL RELATIONS OF 
seen mid-styled stigmas rougher than those of the long-styled. 
The degree to which the longer and middle stamens are graduated 
in length and are upturned at their ends is variable; sometimes 
all are equal. The colour of the green pollen in the long stamens 
is variable *, and is sometimes pale greenish yellow ; in one short- 
styled plant it was almost white. The grains vary a little in 
size: I examined one short-styled plant with the grains above 
the average size; and I have seen a long-styled plant with un- 
distinguishable grains from the longer and shorter anthers. We 
have here considerable fluctuations of character; and if any of 
these slight structural differences were of direct service to the 
plant, or were correlated with useful functional differences, we 
can perceive that the species is just in that state in which natural 
selection might readily do much for its modification. 
To return to our proper subject—we sce that there are three 
kinds of females and three kinds of males, each kind of the latter 
being borne by half-dozens on two of the three forms. It remains 
to discover whether these several sexes or sexual organs differ from 
each other in function. Nothing brings more prominently forward 
the complexity of the reproductive system of this extraordinary 
plant, than the necessity, in order to ascertain the above fact, of 
artificially making eighteen distinct unions. Thus the long-styled 
form had to be fertilized with pollen from its own two distinct 
kinds of anthers, from the two in the mid-styled, and from the two 
in the short-styled form. The same process had to be repeated 
with both the mid- and short-styled forms. It might have been 
thought sufficient to have tried on each stigma the green pollen, 
for instance, from either the mid- or short-styled longer stamens, 
and not from both; but the result proves that this would have 
been insufficient, and that it was necessary to try all six kinds of 
pollen on each stigma. As in artificial fertilizations there will 
always be some failures, it would have been advisable to have 
* Lagerstremia Indica, one of the Lythraces, is strangely variable in its 
stamens—I presume in part due to its growth in a hothouse. The most per- 
fect flowers produced with me five very long stamens with thick flesh-coloured 
filaments and green pollen, and from nineteen to twenty-nine short stamens with 
yellow pollen; but many flowers produced only one, two, three, or four long 
stamens with green pollen, which in some of the anthers was wholly replaced 
by yellow pollen ; one anther offered the singular case of half, or one cell being 
filled with bright green, and the other cell with bright yellow pollen. One petal 
had a furrow near its base, which contained pollen. According to analogy with 
Lythrum, this species would produce three forms ; if so, the above plant was & 
mid-styled form: it was quite sterile with its own two kinds of pollen. 
mi d. tiii a 
