A self-fertilised plant of the same parentage as those in Table 2/12 had been raised in a separate pot for a distinct purpose; and it proved partially sterile, the anthers containing very little pollen.  Several flowers on this plant were crossed with the little pollen which could be obtained from the other flowers on the same plant; and other flowers were self-fertilised.  From the seeds thus produced four crossed and four self-fertilised plants were raised, which were planted in the usual manner on the opposite sides of two pots.  All these four crossed plants were inferior in height to their opponents; they averaged 78.18 inches, whilst the four self-fertilised plants averaged 84.8 inches; or as 100 to 108. (2/2.  From one of these self-fertilised plants, spontaneously self-fertilised, I gathered twenty-four capsules, and they contained on an average only 3.2 seeds per capsule; so that this plant had apparently inherited some of the sterility of its parent.) This case, therefore, confirms the last.  Taking all the evidence together, we must conclude that these strictly self-fertilised plants grew a little taller, were heavier, and generally flowered before those derived from a cross between two flowers on the same plant.  These latter plants thus present a wonderful contrast with those derived from a cross between two distinct individuals.

The effects on the offspring of A cross with A distinct or fresh stock
belonging to the same variety.

From the two foregoing series of experiments we see, firstly, the good effects during several successive generations of a cross between distinct plants, although these were in some degree inter-related and had been grown under nearly the same conditions; and, secondly, the absence of all such good effects from a cross between flowers on the same plant; the comparison in both cases being made with the offspring of flowers fertilised with their own pollen.  The experiments now to be given show how powerfully and beneficially plants, which have been intercrossed during many successive generations, having been kept all the time under nearly uniform conditions, are affected by a cross with another plant belonging to the same variety, but to a distinct family or stock, which had grown under different conditions.

[Several flowers on the crossed plants of the ninth generation in Table 2/10, were crossed with pollen from another crossed plant of the same lot.  The seedlings thus raised formed the tenth intercrossed generation, and I will call them the “Intercrossed plants.”  Several other flowers on the same crossed plants of the ninth generation were fertilised (not having been castrated) with pollen taken from plants of the same variety, but belonging to a distinct family, which had been grown in a distant garden at Colchester, and therefore under somewhat