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.


CHAPTER 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.