A SUMMARY OF THE HEIGHTS AND WEIGHTS OF THE CROSSED AND SELF-FERTILISED PLANTS.
Number of species and plants measured.—Tables given.—Preliminary remarks on the offspring of plants crossed by a fresh stock.—Thirteen cases specially considered.—The effects of crossing a self-fertilised plant either by another self-fertilised plant or by an intercrossed plant of the old stock.—Summary of the results.—Preliminary remarks on the crossed and self-fertilised plants of the same stock.—The twenty-six exceptional cases considered, in which the crossed plants did not exceed greatly in height the self-fertilised.—Most of these cases shown not to be real exceptions to the rule that cross-fertilisation is beneficial.—Summary of results.—Relative weights of the crossed and self-fertilised plants.
VIII.
DIFFERENCE BETWEEN CROSSED AND SELF-FERTILISED PLANTS IN CONSTITUTIONAL VIGOUR AND IN OTHER RESPECTS.
Greater constitutional vigour of crossed plants.—The effects of great crowding.—Competition with other kinds of plants.—Self-fertilised plants more liable to premature death.—Crossed plants generally flower before the self-fertilised.—Negative effects of intercrossing flowers on the same plant.—Cases described.—Transmission of the good effects of a cross to later generations.—Effects of crossing plants of closely related parentage.—Uniform colour of the flowers on plants self-fertilised during several generations and cultivated under similar conditions.
IX.
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.