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Rare instances point to poor races, but the magnolias and lime-trees are often so productive of ascidia as to suggest the idea of ever-sporting varieties. I have seen many hundred ascidia on one lime-tree, and far above a hundred on the magnolia.
Here also we encounter more doubts than real facts, and much remains to be done before exact calculations may become of real scientific value. Returning to the question of the effects of selection in the long run, two essentially different cases are to be considered. Extremes may be selected from among the variants of ordinary fluctuating variability, or from ever-sporting varieties.
Mixed seed or seed from medium types would soon yield plants with too broad stripes, and therefore less diversified flowers. In horticulture, new varieties, both retrograde and ever-sporting, are known to occur almost yearly. Nevertheless, not every novelty of the gardener is to be considered as a mutation in the scientific sense of the word.
The complete development of the varietal character is a question restricted to ever-sporting varieties, since in white flowers and other constant varieties this degree is variable in a very small and unimportant measure. Hence the double flowers seem to afford a very good example for this discussion. It can be decided by two facts.
The same assertion holds good in many other cases, as with Azalea and Camellia. And the striped varieties of these genera belong to the group of ever-sporting forms, and therefore will be considered later on. So it is with carnations and pinks, which occasionally vary by layering, and of which some kinds are so uncertain in character that they are called by floriculturists "catch-flowers."
Many monstrosities, such as fasciated branches, pitchers, split leaves, peloric flowers, and others constitute such ever-sporting varieties, repeating their anomalies year by year and generation after generation, changing as much as possible, but remaining absolutely true within their limits as long as the variety exists.
In the case of the bulbous buttercup, Ranunculus bulbosus, I have succeeded in isolating this secondary summit, although not in a separate variety, but only in a form corresponding to the type of ever-sporting varieties. Recapitulating the results of this too condensed discussion, we may state that fluctuations are linear, being limited to an increase and to a decrease of the characters.
So much concerning ever-sporting varieties and double adaptations. We now come to the effects of a continuous selection of simple characters. Here the sugar-beets stand preeminent. Since Vilmorin's time they have been selected according to the amount of sugar in their roots, and the result has been the most striking that has ever been attained, if considered from the standpoint of practice.
But this number gradually diminishes as the season advances. It would be quite superfluous to give further proof of the general validity of the law of periodicity in ever-sporting varieties. One of the most curious anomalies that may be met with in ornamental garden-plants is the conversion of stamens into pistils.
Presumably there is nowhere a real transgression of the limits, and never or only very rarely and at long intervals of time a true production of another race with other hereditary qualities. Both of them are ever-sporting varieties.
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