If the relative heights of the crossed and self-fertilised plants had been due to mere chance, there would have been about as many cases of self-fertilised plants exceeding the crossed in height by above five per cent as of the crossed thus exceeding the self-fertilised; but we see that of the latter there are fifty-seven cases, and of the former only eight cases; so that the cases in which the crossed plants exceed in height the self-fertilised in the above proportion are more than seven times as numerous as those in which the self-fertilised exceed the crossed in the same proportion. For our special purpose of comparing the powers of growth of crossed and self-fertilised plants, it may be said that in fifty-seven cases the crossed plants exceeded the self-fertilised by more than five per cent, and that in twenty-six cases (18 + 8) they did not thus exceed them. But we shall now show that in several of these twenty-six cases the crossed plants had a decided advantage over the self-fertilised in other respects, though not in height; that in other cases the mean heights are not trustworthy, owing to too few plants having been measured, or to their having grown unequally from being unhealthy, or to both causes combined. Nevertheless, as these cases are opposed to my general conclusion I have felt bound to give them. Lastly, the cause of the crossed plants having no advantage over the self-fertilised can be explained in some other cases. Thus a very small residue is left in which the self-fertilised plants appear, as far as my experiments serve, to be really equal or superior to the crossed plants. We will now consider in some little detail the eighteen cases in which the self-fertilised plants equalled in average height the crossed plants within five per cent; and the eight cases in which the self-fertilised plants exceeded in average height the crossed plants by above five per cent; making altogether twenty-six cases in which the crossed plants were not taller than the self-fertilised plants in any marked degree. [1. Dianthus caryophyllus (third generation).