CHAP. VL CROSSED AND SELF-FERTILISED PLANTS. 193 



which all the remaining seeds had been thickly sown, were from 

 the first finer plants than the self-fertilised, and had larger 

 leaves. At the period when the two tallest crossed plants in 

 this pot were 6| and 4| inches high, the two tallest self-fertilised 

 were only 4 inches. When the two crossed plants were 12 and 

 10 inches high, the two self-fertilised were only 8 inches. These 

 latter plants, as well as many others on the same side of this pot, 

 never grew any higher, whereas several of the crossed plants 

 grew to the height of two feet! On account of this great 

 superiority of the crossed plants, the plants on neither side of 

 this pot have been included in the two last tables. 



Thirty flowers on the crossed plants in Pots I. and IV. (Table 

 LXXIX.) were again crossed, and produced seventeen capsules. 

 Thirty flowers on the self-fertilised plants in the same two pots 

 were again self-fertilised, but produced only seven capsules. 

 The contents of each capsule of both lots were placed in separate 

 watch-glasses, and the seeds from the crossed appeared to the 

 eye to be at least double the number of those from the self- 



In order to ascertain whether the fertility of the self-fertilised 

 plants had been lessened by the plants having been self-ferti- 

 lised for the three previous generations, thirty flowers on the 

 crossed plants were fertilised with their own pollen. These 

 yielded only five capsules, and their seeds being placed in 

 separate watch-glasses did not seem more numerous than those 

 from the capsules on the self-fertilised plants self-fertilised for 

 the fourth time. So that as far as can be judged from so few 

 capsules, the self-fertility of the self-fertilised plants had not 

 decreased in comparison with that of the plants which had 

 been intercrossed during the three previous generations. It 

 should, however, be remembered that both lots of plants 

 had been subjected in each generation to almost exactly similar 

 conditions. 



Seeds from the crossed plants again crossed, and from the self- 

 fertilised again self-fertilised, produced by the plants in Pot I. 

 (Table LXXIX.), in which the three self-fertilised plants were 

 on an average only a little taller than the crossed, were used in 

 the following experiment. They were kept separate from two 

 similar lots of seeds produced by the two plants in Pot IV. in 

 the same table, in which the crossed plant was much taller than 

 its self-fertilised opponent. 



Crossed and self-fertilised Plants of the Fourth Generation 



