The Different Forms of Flowers on Plants of the Same Species

What it is

This book by Charles Darwin was published in 1877 by John Murray in London. It studies plants such as the cowslip and primrose that produce two or three different flower forms, with stamens and styles of varying lengths. Darwin's son Francis Darwin assisted with the research and later wrote a preface to a second edition. The book was dedicated to the botanist Asa Gray.

Why it matters

Darwin showed, through many pollination experiments, that these different flower forms exist to encourage cross-fertilisation between plants, increasing fertility. This extended his theory of natural selection into fine structural detail, demonstrating how seemingly odd variations serve a clear evolutionary purpose. Francis Darwin later said this was work his father found especially satisfying.

Look closer

• What does the title page tell you about where and when this book was printed?
• Why might Darwin have dedicated this book to a fellow scientist rather than a family member?
• How might years of patient observation of ordinary flowers lead to a new scientific idea?