Charles Darwin 
The Effects of Cross and Self-Fertilisation in the Vegetable Kingdom [EPUB ebook] 

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.