The Different Forms of Flowers on Plants of the Same Species (Barnes & Noble Digital Library‪)‬

First published in book form in 1877, this volume of Darwin’s pioneering research on the heterostylous reproductive systems in flowering plants remains the basis of much exciting original research in the field of botany today. Darwin himself revealed, “I do not think anything in my scientific life has given me so much satisfaction as making out the meaning of the structure of these plants.”