Chap. I. INTRODUCTORY REMARKS. 21 



individuals, and as several flowers on the mother-plant 

 were crossed by pollen taken from several flowers on 

 the father-plant, such seedlings would be in one sense 

 half-brothers or sisters, but more closely related than 

 are the half-brothers and sisters of ordinary animals. 

 The flowers on the mother-plant were, however, com- 

 monly crossed by pollen taken from two or more dis- 

 tinct plants ; and in these cases the seedlings might 

 be called with more truth half-brothers or sisters. 

 When two or three mother-plants were crossed, as often 

 happened, by pollen taken from two or three father- 

 plants (the seeds being all intermingled), some of the 

 seedlings of the first generation would be in no way 

 related, whilst many others would be whole or half- 

 brothers and sisters. In the second generation a large 

 number of the seedlings would be what may be called 

 whole or half first-cousins, mingled with whole and 

 half-brothers and sisters, and with some plants not at 

 all related. So it would be in the succeeding genera- 

 tions, but there would also be many cousins of the 

 second and more remote degrees. The relationship will 

 thus have become more and more inextricably complex 

 in the later generations ; with most of the plants in 

 some degree and many of them closely related. 



I have only one other point to notice, but this is one 

 of the highest importance ; namely, that the crossed 

 and self-fertilised plants were subjected in the same 

 generation to as nearly similar and uniform conditions as 

 was possible. In the successive generations they were 

 exposed to slightly different conditions as the seasons 

 varied, and they were raised at different periods. But 

 in other respects all were treated alike, being grown 

 in pots in the same artificially prepared soil, being 

 watered at the same time, and kept close together 

 in the same greenhouse or hothouse. They were 



