168 On the Species of the Genus Primula in Essex.
The results of counting 33,409 Primula seeds have now
been given. These results are not in all cases satisfactory,
but the probable reason for this has nearly always been
apparent. Admitting, then, the correctness of the state-
ments on this subject made by Mr. Darwin (ante, p. 163),
it may be well asked, "How can this be reconciled with
what was shown in the preceding section of this paper ?
How, if one form produces considerably more seeds than
the other, can that other form be considerably the more
abundant in Nature?" I am bound to confess that I do
not know. Mr. Gibbs, of Chelmsford, who has had con-
siderable experience in crossing and growing Primulas, and
whose opinion is therefore worthy of reliance, has kindly
written me as follows:—"If the long-styled form of any
Primula be most numerous and the short-styled most fertile,
it suggests the question—How does this come about? Do
the short-styled seeds produce an excess of long-styled plants,
or are the seeds of long-styled plants better fitted to sur-
vive, though less numerous ? It may be that the seeds of
the long-styled form have the advantage in precocity of
growth or in the distance to which the seeds are thrown,
or fall, though only so much as an inch beyond the parental
leaves. Many seedling primroses perish from being crowded
in germination or from being covered by the leaves of the
parent plant." He adds that he "believes the seeds from
short-styled plants give origin to feebler plants."
These observations then suggest several interesting in-
quiries, and lead me to the belief that there is some fact
with regard to the reciprocal fertilization of Primulas which,
in spite of the attention of Mr. Darwin, has not as yet been
recorded. Prof. Oliver has stated25 that the unfertilized
ovules of the s. are considerably smaller than those of the 1.;
and Darwin supposes that possibly the 1. seeds, being fewer,
have more room for complete development, although when
counting I did not observe any difference in size between the
seed of the two forms (the capsules being of equal size, I
believe). The fact that, in one species at least, the finest
25 'Natural History Review,' July, 1862, p. 237.