found in Madagascar. Background Charles Darwin grew up with an interest in natural history, and as a student at the University of Cambridge he became a pupil and close friend of botany professor John Stevens Henslow. The year he graduated, Darwin was given a supernumerary position as a gentleman naturalist and geologist on the second voyage of HMS Beagle, a trip that lasted five years. By the time he returned in October 1836, he had doubts about the doctrine that species were fixed and unchanging. Within months, experts informed him that specimens he had collected were separate species, not just varieties, and the patterns he saw inspired the inception of his theory of natural selection in 1838. Darwin began editing and publishing the expert reports, collected in the Zoology of the Voyage of H.M.S. Beagle, at the same time as writing a series of books on geology, the first of which was The Structure and Distribution of Coral Reefs. His "species work" was his "prime hobby", a background to this writing, but it evolved into an extensive research programme during the twenty years before he published his theory. Insect fertilisation of plants Darwin's speculations on the origin of species convinced him that cross-fertilisation played an important role in keeping specific forms consistent. He rejected the doctrine that the characteristics of a species were static, and was aware from animal husbandry that inbreeding could lead to changes, often deleterious. He thought that natural outbreeding through cross-fertilisation would keep wild species homogenous yet vigorous. Cross-fertilisation would confer an evolutionary advantage by spreading favourable changes throughout a reproductive community. His ideas were contrary to the common supposition that plants were usually self-fertilising, and so every summer Darwin investigated the contribution of insect pollination to the cross-pollination of flowers. In the summer of 1841 Charles and Emma Darwin moved from the turmoil of London to the countryside, to Down House, a quiet former parsonage in the village of Downe. He wrote, "The flowers are here very beautiful". Darwin followed the recommendation of his friend, the leading botanist Robert Brown, and read Das entdeckte Geheimnis der Natur im Bau und in der Befruchtung der Blumen (The Secret of Nature in the Form and Fertilisation of Flowers Discovered). The little known book, published in 1793 by Christian Konrad Sprengel but never translated into English, introduced the idea that flowers were created by God to fulfill a