varieties of, rarely intercross, but a cross between them highly
beneficial.--Sarothamnus scoparius, wonderful effects of a
cross.--Ononis minutissima, cleistogene flowers of.--Summary on the
Leguminosae.--Clarkia elegans.--Bartonia aurea.--Passiflora
gracilis.--Apium petroselinum.--Scabiosa atropurpurea.--Lactuca
sativa.--Specularia speculum.--Lobelia ramosa, advantages of a cross
during two generations.--Lobelia fulgens.--Nemophila insignis, great
advantages of a cross.--Borago officinalis.--Nolana prostrata.


CHAPTER VI.

SOLANACEAE, PRIMULACEAE, POLYGONEAE, ETC.

Petunia violacea, crossed and self-fertilised plants compared for four
generations.--Effects of a cross with a fresh stock.--Uniform colour of
the flowers on the self-fertilised plants of the fourth
generation.--Nicotiana tabacum, crossed and self-fertilised plants of
equal height.--Great effects of a cross with a distinct sub-variety on
the height, but not on the fertility, of the offspring.--Cyclamen
persicum, crossed seedlings greatly superior to the
self-fertilised.--Anagallis collina.--Primula veris.--Equal-styled
variety of Primula veris, fertility of, greatly increased by a cross
with a fresh stock.--Fagopyrum esculentum.--Beta vulgaris.--Canna
warscewiczi, crossed and self-fertilised plants of equal height.--Zea
mays.--Phalaris canariensis.


CHAPTER VII.