From these figures it is manifest that the red and striped types differ
from one another not only in their visible attributes, but also in the
degree of their heredity. The striped individuals repeat their
peculiarity in 90-98% of their progeny, 2-10% sporting into the uniform
red color. On the other hand the red individuals are constant in 71-84%
of their offspring, while 16-29% go over to the striped type. Or,
briefly, both types are inherited to a high degree, but the striped type
is more strictly inherited than the red one.
Moreover the figures show that the degree of inheritance is not
contingent upon the question as to how the sport may have arisen.
Bud-sports show the same degree of inheritance as seed-sports. Sexual
and asexual variability therefore seem to be one and the same process in
this instance. But the deeper meaning of this and other special features
of our genealogical tree are still awaiting further investigation. It
seems that much important evidence might [321] come from an extension of
this line of work. Perhaps it might even throw some light on the
intimate nature of the bud-variations of ever-sporting varieties in
general. Sectional variations remain to be tested as to the degree of
inheritance exhibited, and the different occurrences as to the breadth
of the streaks require similar treatment.
In ordinary horticultural practice it is desirable to give some
guarantee as to what may be expected to come from the seeds of brightly
striped flowers. Neither the pure red type, nor the nearly yellow
racemes are the object of the culture, as both of them may be had pure
from their, own separate varieties. In order to insure proper striping,
both extremes are usually rejected and should be rooted out as soon as
the flowering period begins. Similarly the broad-striped ones should be
rejected, as they give a too large amount of uniform red flowers.
Clearly, but not broadly striped individuals always yield the most
reliable seed.
Summing up once more the results of our pedigree-experiment, we may
assert that the striped variety of the snapdragon is wholly permanent,
including the two opposite types of uniform color and of stripes. It
must have been so since it first originated from the invariable uniform
[322] varieties, about the middle of the last century, in the nursery of
Messrs. Vilmorin, and probably it will remain so as long as popular
taste supports its cultivation. It has never been observed to transgress
its limits or to sport into varieties without reversions or sports. It
fluctuates from one extreme to the other yearly, always recurring in the
following year, or even in the same summer by single buds. Highly
variable within its limits, it is absolutely constant or permanent, when
considered as a definite group.
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