8vo. 32pp. publisher's advertisements dated March 1877. (Some spotting flyleaves.) Original blind-stamped green cloth, gilt-stamped spine (spine a bit darkened, joints and fore-corners lightly rubbed).

FIRST EDITION, one of 1250 copies, of Darwin's account of his experiments with cross-pollination. "Darwin noticed that some species of flowers differ by the lengths of their anthers and styles...these observations formed the basis of Different Forms of Flowers (1877)...Darwin had experimentally discovered and demonstrated the fact of hybrid vigor, or heterosis, which is completely explained by Mendelian genetics" (DSB). Freeman 1277; Norman 602.