The above two lots of seeds, after germinating on sand, were planted in pairs on opposite sides of five pots. The two lots of seedlings, when half an inch in height, and again when 6 inches high, were measured to the tips of their leaves, but presented no difference. When fully grown, the flower-stalks were measured to the summits of the seed capsules, with the following result:-- TABLE 4/33. Papaver vagum. Heights of flower-stalks to the summits of the seed capsules measured in inches. Column 1: Number (Name) of Pot. Column 2: Crossed Plants. Column 3: Self-fertilised Plants. Pot 1 : 24 2/8 : 21. Pot 1 : 30 : 26 5/8. Pot 1 : 18 4/8 : 16. Pot 2 : 14 4/8 : 15 3/8. Pot 2 : 22 : 20 1/8. Pot 2 : 19 5/8 : 14 1/8. Pot 2 : 21 5/8 : 16 4/8. Pot 3 : 20 6/8 : 19 2/8. Pot 3 : 20 2/8 : 13 2/8. Pot 3 : 20 6/8 : 18. Pot 4 : 25 3/8 : 23 2/8. Pot 4 : 24 2/8 : 23. Pot 5 : 20 : 18 3/8. Pot 5 : 27 7/8 : 27. Pot 5 : 19 : 21 2/8. Total : 328.75 : 293.13. The fifteen crossed plants here average 21.91 inches, and the fifteen self-fertilised plants 19.54 inches in height, or as 100 to 89. These plants did not differ in fertility, as far as could be judged by the number of capsules produced, for there were seventy-five on the crossed side and seventy-four on the self-fertilised side. Eschscholtzia californica. This plant is remarkable from the crossed seedlings not exceeding in height or vigour the self-fertilised. On the other hand, a cross greatly increases the productiveness of the flowers on the parent-plant, and is indeed sometimes necessary in order that they should produce any seed; moreover, plants thus derived are themselves much more fertile than those raised from self-fertilised flowers; so that the whole advantage of a cross is confined to the reproductive system. It will be necessary for me to give this singular case in considerable detail.