Beschreibung:

CHARLES DARWIN (1809-1882) Autograph sketch of the dimorphic flowers of the primrose, n.p., n.d. [1861], with autograph notes on the lower half of the same page, in pencil and brown ink on paper laid on card, one page, 202 x 165mm, margins trimmed (slight wear in centrefold). The sketch and notes are apparently a guide for WH Fitch in his illustration of Darwin's paper 'On the Two Forms, or Dimorphic Condition, in the Species of Primula , and on their remarkable Sexual Relations' in the Journal of the Proceedings of the Linnean Society , Vol. VI, No. 22, 1 March 1862, 77. Below his sketch, Darwin notes 'Points to be attended to', specifically the proportions of the different parts of the flower, which are labelled on the sketch for Fitch's benefit, the title 'Longitudinal Section of Common Primrose ', and the instruction 'Clean, hard outlines for 2 woodcuts, matching in size & to stand next alongside each other'. BOTANICAL SKETCHES BY DARWIN ARE EXTREMELY RARE AT AUCTION. Darwin's paper on primroses, the first of a series on heterostyled plants, concentrated on a problem which appeared to be of trivial significance, namely the variability in the length of the style in the common primrose. By dint of extensive experimentation - which, he commented, gave him more pleasure than almost any other research - Darwin demonstrated that the two forms of the primrose - the long-styled and short-styled - replicate to some degree the relation between the sexes in animals. His experimental results, indicating that crosses between the two forms were more fertile than crosses of a single form, demonstrated the advantages of sexual as opposed to asexual reproduction in increasing genetic variability, and hence the evolutionary value of the existence of the difference of sexes within a species. The lot also includes off-prints from the Linnean Society Journal of a number of Darwin's papers on heterostyled plants: 'On the Two Forms, or Dimorphic Condition, in the Species of Primula' (1862), 'On the Existence of Two Forms, and on their Reciprocal Sexual Relation, in Several Species of the Genus Linum' (1863), 'On the Sexual Relations of the Three Forms of Lythrum salicaria ' (1864), with a cut inscription in Darwin's autograph ('from the Author') pasted on the inside upper cover, and 'On Specific Differences in Primula' (1869), inscribed in Darwin's autograph ('From the Author') on the upper cover.