CONVOLVULACEAE.

Ipomoea purpurea, comparison of the height and fertility of the crossed
and self-fertilised plants during ten successive generations.--Greater
constitutional vigour of the crossed plants.--The effects on the
offspring of crossing different flowers on the same plant, instead of
crossing distinct individuals.--The effects of a cross with a fresh
stock.--The descendants of the self-fertilised plant named
Hero.--Summary on the growth, vigour, and fertility of the successive
crossed and self-fertilised generations.--Small amount of pollen in the
anthers of the self-fertilised plants of the later generations, and the
sterility of their first-produced flowers.--Uniform colour of the
flowers produced by the self-fertilised plants.--The advantage from a
cross between two distinct plants depends on their differing in
constitution.


CHAPTER III.

SCROPHULARIACEAE, GESNERIACEAE, LABIATAE, ETC.

Mimulus luteus; height, vigour, and fertility of the crossed and
self-fertilised plants of the first four generations.--Appearance of a
new, tall, and highly self-fertile variety.--Offspring from a cross
between self-fertilised plants.--Effects of a cross with a fresh
stock.--Effects of crossing flowers on the same plant.--Summary on
Mimulus luteus.--Digitalis purpurea, superiority of the crossed
plants.--Effects of crossing flowers on the same
plant.--Calceolaria.--Linaria vulgaris.--Verbascum thapsus.--Vandellia
nummularifolia.--Cleistogene flowers.--Gesneria pendulina.--Salvia