1 64 CHARLES DARWIN 



abandoned entirely his original intention of publishing 

 in detail the basis of his first book, and contented him- 

 self instead with tracing out minutely some minor 

 portions of his contemplated task as specimens of evo- 

 lutionary method. 



In 1877, in pursuance of this changed purpose, 

 Darwin published his book on ' Forms of Flowers,' in 

 which he dealt closely with the old problem of differ- 

 ently shaped blossoms on plants of the same species. 

 It had long been known, to take a single example, that 

 primroses existed in two forms, the pin-eyed and the 

 thrum-eyed, of which the former has the pin-like 

 summit of the pistil at the top of the tube, and the 

 stamens concealed half way down its throat ; while in 

 the latter these relative positions are exactly reversed, 

 the stamens answering in place to the pistil of the 

 alternative form with geometrical accuracy. As early 

 as 1862 Darwin had shown, in the 'Journal of the 

 Linnean Society,' that this curious arrangement owed 

 its development to the greater security which it afforded 

 for cross-fertilisation, because in this way each flower 

 had to be impregnated with the pollen from a totally 

 distinct blossom, growing on a different individual 

 plant. In a series of successive papers read before the 

 same Society in the years between 1863 and 1868, he 

 had extended a similar course of explanation to the 

 multiform flowers of the flaxes, the loosestrifes, the 

 featherfoil, the auricula, the buckbean, and several other 

 well-known plants. At last, in 1877, he gathered to- 

 gether into one of the now familiar green-covered 

 volumes the whole of his observations on this strange 

 peculiarity, and proved by abundant illustration and 



