We meet with analogous cases with plants. Striped flowers, though they can be
propagated truly by seed, have a latent tendency to become uniformly coloured,
but when once crossed by a uniformly coloured variety, they ever afterwards
fail to produce striped seedlings. (14/22. Verlot 'Des Varietes' 1865 page
66.) Another case is in some respects more curious: plants bearing peloric
flowers have so strong a latent tendency to reproduce their normally irregular
flowers, that this often occurs by buds when a plant is transplanted into
poorer or richer soil. (14/23. Moquin-Tandon 'Teratologie' page 191.) Now I
crossed the peloric snapdragon (Antirrhinum majus), described in the last
chapter, with pollen of the common form; and the latter, reciprocally, with
peloric pollen. I thus raised two great beds of seedlings, and not one was
peloric. Naudin (14/24. 'Nouvelles Archives du Museum' tome 1 page 137.)
obtained the same result from crossing a peloric Linaria with the common form.
I carefully examined the flowers of ninety plants of the crossed Antirrhinum
in the two beds, and their structure had not been in the least affected by the
cross, except that in a few instances the minute rudiment of the fifth stamen,
which is always present, was more fully or even completely developed. It must
not be supposed that this entire obliteration of the peloric structure in the
crossed plants can be accounted for by any incapacity of transmission; for I
raised a large bed of plants from the peloric Antirrhinum, artificially
fertilised by its own pollen, and sixteen plants, which alone survived the
winter, were all as perfectly peloric as the parent-plant. Here we have a good
instance of the wide difference between the inheritance of a character and the
power of transmitting it to crossed offspring. The crossed plants, which
perfectly resembled the common snapdragon, were allowed to sow themselves, and
out of a hundred and twenty-seven seedlings, eighty-eight proved to be common
snapdragons, two were in an intermediate condition between the peloric and
normal state, and thirty-seven were perfectly peloric, having reverted to the
structure of their one grand-parent. This case seems at first sight to offer
an exception to the rule just given, namely, that a character which is present
in one form and latent in the other is generally transmitted with prepotent
force when the two forms are crossed. For in all the Scrophulariaceae, and
especially in the genera Antirrhinum and Linaria, there is, as was shown in
the last chapter, a strong latent tendency to become peloric; but there is
also, as we have seen, a still stronger tendency in all peloric plants to
reacquire their normal irregular structure. So that we have two opposed latent
tendencies in the same plants. Now, with the crossed Antirrhinums the tendency
to produce normal or irregular flowers, like those of the common Snapdragon,
prevailed in the first generation; whilst the tendency to pelorism, appearing
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