402 MB. C. DARWIIS' OX THE ILLEGITIMATE OFFSPBIKU 



longer and many of its shorter stamens contabescent, produced 

 only 52 per cent, of the proper number of seeds. 



Eocp. XXII. — This short-styled plant produced perfectly sound 

 pollen, as viewed under the microscope. During 1866 it was freely 

 and legitimately fertilized by other illegitimate plants belonging 

 to the present and the following class, both of which include many 

 highly fertile plants. Under these circumstances it yielded from 

 eight capsules an average of 100*5 seeds, with a maximum of 123 

 and a minimum of 86 ; so that it produced 121 per cent, of seeds 

 in comparison with the normal standard. During 1SG4 it was 

 allowed to be freely and legitimately fertilized by legitimate and 

 illegitimate plants, and yielded an average, from eight capsules, of 

 104'2 seeds, with a maximum of 125 and a minimum of 90 ; con- 

 sequently it produced 125 per cent, of the normal standard. In 

 this case, as in some previous cases, pollen from legitimate plants 

 added in a small degree to the fertility of the plant ; and the fer- 

 tility would, perhaps, have been still greater had not the summer 

 of 1864 been very hot, and certainly unfavourable to some of the 

 plants of Lythrum. 



JExp. XXIII. — This short-styled plant produced perfectly sound 

 pollen. During 1866 it was freely and legitimately fertilized by 

 the other illegitimate plants specified under the last experiment, 

 and yielded an average, from eight capsules, of 113*5 seeds, with a 

 maximum of 123 and a minimum of 93, Hence this plant pro- 

 duced no less than 136 per cent, of the normal standard. 



Exp. XXIV. — This long-styled plant produced pollen which 

 seemed under the microscope sound; but some of the grains did 

 not swell when placed in water. During 1864 it was legitimately 

 fertilized by legitimate and illegitimate plants in the manner de- 

 scribed under Exp. XXII., but yielded an average, from ten cap- 

 sules, of only 55 seeds, with a maximum of 88 and a minimum of 

 24, thus attainining 59 per cent, of the normal fertility. This 

 low degree of fertility, I presume, was owing to the unfavourable 

 season ; for during 1866, when legitimately fertilized by illegiti- 

 mate plants in the manner described under Exp. XXII., it yielded 

 an average, from eight capsules, of 82 seeds, with a maximum of 

 120 and a minimum of 67, thus producing 88 per cent, of the 

 normal number of seeds. 



Exp. XXA^. — The pollen of this long-styled plant contained a 

 moderate number of poor and shrivelled grains ; and this is a sur- 

 prising circumstance, as it yielded an extraordinary number ot 

 seeds. During 1866 it was freely and legitimately fertilized by 



