CHAP. II. SUMMARY OF OBSERVATIONS. 59 



may have occurred earlier. Several anthers from flowers 

 on the crossed and self-fertilised plants of the eighth 

 generation were compared under the microscope ; and 

 those from the former were generally longer and plainly 

 broader than the anthers of the self-fertilised plants. 

 The quantity of pollen contained in one of the latter 

 was, as far as could be judged by the eye, about half 

 of that Contained in one from a crossed plant. The 

 impaired fertility of the self-fertilised plants of the 

 eighth generation was also shown in another manner, 

 which may often be observed in hybrids namely, by the 

 first-formed flowers being sterile. For instance, the 

 fifteen first flowers on a self-fertilised plant of one of the 

 later generations were carefully fertilised with their 

 own pollen, and eight of them dropped off; at the same 

 time fifteen flowers on a crossed plant growing in the 

 same pot were self-fertilised, and only one dropped off. 

 On two other crossed plants of the same generation, 

 several of the earliest flowers were observed to fertilise 

 themselves and to produce capsules. In the plants of 

 the ninth, and I believe of some previous generations, 

 very many of the flowers, as already stated, were 

 slightly monstrous ; and this probably was connected 

 with their lessened fertility. 



All the self-fertilised plants of the seventh genera- 

 tion, and I believe of one or two previous generations, 

 produced flowers of exactly the same tint, namely, of a 

 rich dark purple. So did all the plants, without any 

 exception, in the three succeeding generations of self- 

 fertilised plants ; and very many were raised on account 

 of other experiments in progress not here recorded. 

 My attention was first called to this fact by my 

 gardener remarking that there was no occasion to label 

 the self-fertilised plants, as they could always be known 

 by their colour. The flowers were as uniform in tint 



