Book contents
- Frontmatter
- Contents
- CHAPTER I INTRODUCTORY REMARKS
- CHAPTER II CONVOLVULACEÆ
- CHAPTER III SCROPHULARIACEÆ, GESNERIACEÆ, LABIATÆ, ETC
- IV CRUCIFERÆ, PAPAVERACEÆ, RESEDACEÆ, ETC
- CHAPTER V GERANIACEÆ, LEGUMINOSÆ, ONAGRACEÆ, ETC
- CHAPTER VI SOLANACEÆ PRIMULACEÆ, POLYGONEÆ, ETC
- CHAPTER VII SUMMARY OF THE HEIGHTS AND WEIGHTS OF THE CROSSED AND SELF-FERTILISED PLANTS
- CHAPTER VIII DIFFERENCE BETWEEN CROSSED AND SELF-FERTILISED PLANTS IN CONSTITUTIONAL VIGOUR AND IN OTHER RESPECTS
- CHAPTER IX THE EFFECTS OF CROSS-FERTILISATION AND SELF-FERTILISATION ON THE PRODUCTION OF SEEDS
- CHAPTER X MEANS OF FERTILISATION
- CHAPTER XI THE HABITS OF INSECTS IN RELATION TO THE FERTILISATION OF FLOWERS
- CHAPTER XII GENERAL RESULTS
- INDEX
CHAPTER XII - GENERAL RESULTS
Published online by Cambridge University Press: 29 August 2010
- Frontmatter
- Contents
- CHAPTER I INTRODUCTORY REMARKS
- CHAPTER II CONVOLVULACEÆ
- CHAPTER III SCROPHULARIACEÆ, GESNERIACEÆ, LABIATÆ, ETC
- IV CRUCIFERÆ, PAPAVERACEÆ, RESEDACEÆ, ETC
- CHAPTER V GERANIACEÆ, LEGUMINOSÆ, ONAGRACEÆ, ETC
- CHAPTER VI SOLANACEÆ PRIMULACEÆ, POLYGONEÆ, ETC
- CHAPTER VII SUMMARY OF THE HEIGHTS AND WEIGHTS OF THE CROSSED AND SELF-FERTILISED PLANTS
- CHAPTER VIII DIFFERENCE BETWEEN CROSSED AND SELF-FERTILISED PLANTS IN CONSTITUTIONAL VIGOUR AND IN OTHER RESPECTS
- CHAPTER IX THE EFFECTS OF CROSS-FERTILISATION AND SELF-FERTILISATION ON THE PRODUCTION OF SEEDS
- CHAPTER X MEANS OF FERTILISATION
- CHAPTER XI THE HABITS OF INSECTS IN RELATION TO THE FERTILISATION OF FLOWERS
- CHAPTER XII GENERAL RESULTS
- INDEX
Summary
The first and most important of the conclusions which may be drawn from the observations given in this volume, is that cross-fertilisation is generally beneficial, and self-fertilisation injurious. This is shown by the difference in height, weight, constitutional vigour, and fertility of the offspring from crossed and self-fertilised flowers, and in the number of seeds produced by the parent-plants. With respect to the second of these two propositions, namely, that self-fertilisation is generally injurious, we have abundant evidence. The structure of the flowers in such plants as Lobelia ramosa, Digitalis furpurea, &c, renders the aid of insects almost indispensable for their fertilisation; and bearing in mind the prepotency of pollen from a distinct individual over that from the same individual, such plants will almost certainly have been crossed during many or all previous generations. So it must be, owing merely to the prepotency of foreign pollen, with cabbages and various other plants, the varieties of which almost invariably intercross when grown together. The same inference may be drawn still more surely with respect to those plants, such as Keseda and Eschscholtzia, which are sterile with their own pollen, but fertile with that from any other individual. These several plants must therefore have been crossed during a long series of previous generations, and the artificial crosses in my experiments cannot have increased the vigour of the offspring beyond that of their progenitors.
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- Publisher: Cambridge University PressPrint publication year: 2009First published in: 1876