The Effects of Cross and Self Fertilisation in the Vegetable Kingdom The Effects of Cross and Self Fertilisation in the Vegetable Kingdom The Effects of Cross and Self Fertilisation in the Vegetable Kingdom is a book on evolution in plants by Charles Darwin, first published in 1876. In this book Darwin examines the effects of cross and self fertilisation of plants and provides experimental evidence for a hypothesis stated in his famed book of 1859, Origin of Species, that "... in none [i.e. plant] [...]can self-fertilisation go on for perpetuity" ("Origin", p. 101). He reports on experiments conducted on over 60 different species of plants, where he used controlled pollinations in
On the Origin of Species an incipient species" and that "species are only strongly marked and permanent varieties". He argues for the ubiquity of variation in nature. Historians have noted that naturalists had long been aware that the individuals of a species differed from one another, but had generally considered such variations to be limited and unimportant deviations from the archetype of each species, that archetype being a fixed ideal in the mind of God. Darwin and Wallace made variation among individuals of the same species central to understanding the natural world. In Chapter III, Darwin asks how varieties "which I have called incipient species"