[33]

Light

Celery Right Hand Seedling

Fig 203 A

1/2 scale 5 6 sets of lettering Blue lines

[34]

Celery─ Left Hand Seedling

Sept. 16th 1878

Light

B Fig 203 B

1/2 scale 5 sets of lettering Blue Lines

(See Back)

[35]

76

Ipomoea

self-fertilised with their own pollen. I wished, therefore, to ascertain whether a cross between two flowers [illeg] by on the same plant would give to the offspring an equal or any superiority over the offspring from flowers self- fertilised plants with their own pollen. I procured some fresh seed and raised two plants which were covered with a net: and many flowers on them were crossed with pollen from a distinct flower on the same plant. Twenty-nine capsules thus produced contained on an average 4.86 seeds per capsule; and 100 of these seeds weighing 36.77 grains.

Many other flowers were fertilised with their own pollen, and twenty-six capsules thus produced contained on an average 4.42 seeds per capsule; 100 of them which weighed 42.61 grains. So that a cross of this kind appears to have increased slightly the number of seeds in the ratio of 100 to 91;) but these were lighter than the self-fertilised in the ration of 86 to 100, but I doubt however from other observations whether these results is are fully trustworthy. The two lots of seeds after germinating on sand, were planted in pairs on the opposite sides

[Cross and self fertilisation, pp. 42-3: "In all the foregoing experiments, seedlings from flowers crossed by pollen from a distinct plant (though in the later generations more or less closely related) were put into competition with, and almost invariably proved markedly superior in height to the offspring from self-fertilised flowers. I wished, therefore, to ascertain whether a cross between two flowers on the same plant would give to the offspring any superiority over the offspring from flowers fertilised with their own pollen. I procured some fresh seed and raised two plants, which were covered with a net; and several of their flowers were crossed with pollen from a distinct flower on the same plant. Twenty-nine capsules thus produced contained on an average 4.86 seeds per capsule; and 100 of these seeds weighed 36.77 grains. Several other flowers were fertilised with their own pollen, and twenty-six capsules thus produced contained on an average 4.42 seeds per capsule; 100 of which weighed 42.61 grains. So that a cross of this kind appears to have increased slightly the number of seeds per capsule, in the ratio of 100 to 91; but these crossed seeds were lighter than the self-fertilised in the ratio of 86 to 100. I doubt, however, from other observations, whether these results are fully trustworthy. The two lots of seeds, after germinating on sand, were planted in pairs on the opposite sides of nine pots, and were treated in every respect like the plants in the previous experiments."]