208 On the Species of the Genus Primula in Essex.
their seeds, although the new crop of seeds was already
beginning to form. This habit of the Oxlip is an exceptional
one, I believe; most plants in this country get rid of last year's
seeds before they begin to produce another crop. A shake will
throw the seeds out of the capsules, and very likely distribute
them to the distance of a foot or so, where they will have
a far better opportunity of growing than if the capsules
were pendant like the flowers and merely threw the seed
down on to the plant. The clusters of capsules form very
pretty objects.
Our three species secrete plenty of nectar, which in hot
weather may often be tasted on pulling out the corolla.
They all emit fairly powerful scents, which are much of
the same kind, yet quite distinguishable. That of the
Oxlip may be somewhat likened to the smell of peaches or
apricots.
The Hybrid Oxlip is easily distinguished from the True
Oxlip. Its extremely variable nature shows that it is not a
true species, and Darwin's elaborate experiments (' Forms of
Flowers,' pp. 63-70) have proved conclusively that it is a
hybrid between the Cowslip and the Primrose. It occurs
more or less commonly in all places where both these grow
full complement of pollen, the stock of the s. would be much diminished.
Thus nectar-seeking insects which effect cross-fertilization would neces-
sarily carry more long-styled pollen to s. than short-styled pollen to 1.,
and consequently the chances of the s. being cross-fertilized would be the
best. Also, inasmuch as the majority of fertilizations would be the result
of the action of long-styled pollen upon the ovules of s., it is conceivable
(assuming the prepotency of the male element in plant-fertilization)
that the "long-stylism" of the pollen would be impressed upon the
resulting seeds, leading eventually to a slight increase in the number
of 1.; while, owing to the "artificial" selection by pollen-gatherers, as
above indicated, the s. would produce the greater quantity of seeds.
In this way also we may explain the discrepancy between Mr. Darwin's
and Mr. Christy's observations. If our hypothesis be true, the relative
numbers of the two forms in any given locality would depend very much
upon the presence or absence of species of pollen-gathering bees. In
places where these insects are common, 1. would tend to increase; but
where they are rare or absent the numbers of the two forms would become
equalized, owing to efficient reciprocal cross-fertilization by nectar-
seeking bees.—Ed.]