In Table 7/C the crossed plants are the offspring of a cross with a fresh stock, or with a distinct variety; and they were put into competition either with self-fertilised plants, or with intercrossed plants of the same old stock. By the term fresh stock I mean a non-related plant, the progenitors of which have been raised during some generations in another garden, and have consequently been exposed to somewhat different conditions. In the case of Nicotiana, Iberis, the red variety of Primula, the common Pea, and perhaps Anagallis, the plants which were crossed may be ranked as distinct varieties or sub-varieties of the same species; but with Ipomoea, Mimulus, Dianthus, and Petunia, the plants which were crossed differed exclusively in the tint of their flowers; and as a large proportion of the plants raised from the same lot of purchased seeds thus varied, the differences may be estimated as merely individual. Having made these preliminary remarks, we will now consider in detail the several cases given in Table 7/C, and they are well worthy of full consideration. 1. Ipomoea purpurea. Plants growing in the same pots, and subjected in each generation to the same conditions, were intercrossed for nine consecutive generations. These intercrossed plants thus became in the later generations more or less closely inter-related. Flowers on the plants of the ninth intercrossed generation were fertilised with pollen taken from a fresh stock, and seedlings thus raised. Other flowers on the same intercrossed plants were fertilised with pollen from another intercrossed plant, producing seedlings of the tenth intercrossed generation. These two sets of seedlings were grown in competition with one another, and differed greatly in height and fertility. For the offspring from the cross with a fresh stock exceeded in height the intercrossed plants in the ratio of 100 to 78; and this is nearly the same excess which the intercrossed had over the self-fertilised plants in all ten generations taken together, namely, as 100 to 77. The plants raised from the cross with a fresh stock were also greatly superior in fertility to the intercrossed, namely, in the ratio of 100 to 51, as judged by the relative weight of the seed-capsules produced by an equal number of plants of the two sets, both having been left to be naturally fertilised. It should be especially observed that none of the plants of either lot were the product of self-fertilisation. On the contrary, the intercrossed plants had certainly been crossed for the last ten generations, and probably, during all previous generations, as we may infer from the structure of the flowers and from the frequency of the visits of humble-bees. And so it will have been with the parent-plants of the fresh stock. The whole great difference in height and fertility between the two lots must be attributed to the one being the product of a cross with pollen from a fresh stock, and the other of a cross between plants of the same old