The Effects of Cross and Self-Fertilisation in the Vegetable Kingdom Page 01

THE EFFECTS OF CROSS & SELF-FERTILISATION IN THE VEGETABLE KINGDOM.

BY

CHARLES DARWIN, M.A., F.R.S., ETC.

CONTENTS.

CHAPTER I.

INTRODUCTORY REMARKS.

Various means which favour or determine the cross-fertilisation of plants.--Benefits derived from cross-fertilisation.--Self-fertilisation favourable to the propagation of the species.--Brief history of the subject.--Object of the experiments, and the manner in which they were tried.--Statistical value of the measurements.--The experiments carried on during several successive generations.--Nature of the relationship of the plants in the later generations.--Uniformity of the conditions to which the plants were subjected.--Some apparent and some real causes of error.--Amount of pollen employed.--Arrangement of the work.--Importance of the conclusions.

CHAPTER II.

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 coccinea.--Origanum vulgare, great increase of the crossed plants by stolons.--Thunbergia alata.

CHAPTER IV.

CRUCIFERAE, PAPAVERACEAE, RESEDACEAE, ETC.

Brassica oleracea, crossed and self-fertilised plants.--Great effect of a cross with a fresh stock on the weight of the offspring.--Iberis umbellata.--Papaver vagum.--Eschscholtzia californica, seedlings from a cross with a fresh stock not more vigorous, but more fertile than the self-fertilised seedlings.--Reseda lutea and odorata, many individuals sterile with their own pollen.--Viola tricolor, wonderful effects of a cross.--Adonis aestivalis.--Delphinium consolida.--Viscaria oculata, crossed plants hardly taller, but more fertile than the self-fertilised.--Dianthus caryophyllus, crossed and self-fertilised plants compared for four generations.--Great effects of a cross with a fresh stock.--Uniform colour of the flowers on the self-fertilised plants.--Hibiscus africanus.

CHAPTER V.

GERANIACEAE, LEGUMINOSAE, ONAGRACEAE, ETC.

Pelargonium zonale, a cross between plants propagated by cuttings does no good.--Tropaeolum minus.--Limnanthes douglasii.--Lupinus luteus and pilosus.--Phaseolus multiflorus and vulgaris.--Lathyrus odoratus, varieties of, never naturally intercross in England.--Pisum sativum, 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.

Charles Darwin

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