230 ILLEGITIMATE OFFSPRING OF CHAP. V. 



of these six illegitimate plants was carefully observed; 

 but I must premise that I cannot give any satisfactory 

 standard of comparison as far as the number of the 

 seeds is concerned; for though I counted the seeds 

 of many legitimate plants fertilised legitimately and ille- 

 gitimately, the number varied so greatly during suc- 

 cessive seasons that no one standard will serve well 

 for illegitimate unions made during different seasons. 

 Moreover the seeds in the same capsule frequently differ 

 so much in size that it is scarcely possible to decide which 

 ought to be counted as good seed. There remains as 

 the best standard of comparison the proportional num- 

 ber of fertilised flowers which produce capsules con- 

 taining any seed. 



First, for the one illegitimate short-styled plant. 

 In the course of three seasons 27 flowers were illegiti- 

 mately fertilised with pollen from the same plant, and 

 they yielded only a single capsule, which, however, con- 

 tained a rather large number of seeds for a union of 

 this nature, namely, 23. As a standard of comparison 

 I may state that during the same three seasons 44 

 flowers borne by legitimate short-styled plants were 

 self-fertilised, and yielded 26 capsules; so that the 

 fact of the 27 flowers on the illegitimate plant having 

 produced only one capsule proves how sterile it was. 

 To show that the conditions of life were favourable, 

 I will add that numerous plants of this and other 

 species of Primula all produced an abundance of 

 capsules whilst growing close by in the same soil with 

 the present and following plants. The sterility of the 

 above illegitimate short-styled plant depended on 

 both the male and female organs being in a deterio- 

 rated condition. This was manifestly the case with 

 the pollen; for many of the anthers were shrivelled 

 or contabescent. Nevertheless some of the anthers 



