Chapter 9

THE EFFECTS OF CROSS-FERTILISATION AND SELF-FERTILISATION ON THE PRODUCTION OF SEEDS.

Fertility of plants of crossed and self-fertilised parentage, both lots being fertilised in the same manner.--Fertility of the parent-plants when first crossed and self-fertilised, and of their crossed and self-fertilised offspring when again crossed and self-fertilised.--Comparison of the fertility of flowers fertilised with their own pollen and with that from other flowers on the same plant.--Self-sterile plants.--Causes of self-sterility.--The appearance of highly self-fertile varieties.--Self-fertilisation apparently in some respects beneficial, independently of the assured production of seeds.--Relative weights and rates of germination of seeds from crossed and self-fertilised flowers.