226 ILLEGITIMATE OFFSPRING OF CHAP. V. 



In this last case we have an instance of reversion in 

 colour, without the possibility of any cross, to the grand- 

 parents or more distant progenitors of the plants in 

 question. Altogether 23 plants in the first generation 

 and 46 in the second generation were raised ; and the 

 whole of these 69 illegitimate plants were long-styled ! 



Eight purple-flowered and two yellow-flowered plants 

 of the first illegitimate generation were fertilised in 

 various ways with their own pollen and with that of 

 the common primrose ; and the seeds were separately 

 counted, but as I could detect no difference in fertility 

 between the purple and yellow varieties, the results 

 are run together in the following table. (See next 

 page.) 



If we compare the figures in this table with those 

 given in the first chapter, showing the normal fertility 

 of the common primrose, we shall see that the illegiti- 

 mate purple- and yellow-flowered varieties are very 

 sterile. For instance, 72 flowers were fertilised with 

 their own pollen and produced only 11 good capsules ; 

 but by the standard they ought to have produced 48 

 capsules ; and each of these ought to have contained 

 on an average 52 - 2 seeds, instead of only 1T5 seeds. 

 When these plants were illegitimately and legiti- 

 mately fertilised with pollen from the common prim- 

 rose, the average numbers were increased, but were far 

 from attaining the normal standards. So it was when 

 both forms of the common primrose were fertilised 

 with pollen from these illegitimate plants; and this 

 shows that their male as well as their female organs 

 were in a deteriorated condition. The sterility of these 

 plants was shown in another way, namely, by their not 

 producing any capsules when the access of all insects 

 (except such minute ones as Thrips) was prevented: 

 for under these circumstances the common long-styled 



