228 ILLEGITIMATE OFFSPRING OF CHAP. V. 



When these plants were illegitimately and legiti- 

 mately fertilised with pollen from the common prim- 

 rose, the average numbers were increased, but Avere 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 

 primrose produces a considerable number of capsules. 

 There can, therefore, be no doubt that the fertility of 

 these plants was greatly impaired. The loss is not 

 correlated with the colour of the flower; and it was to 

 ascertain this point that I made so many experiments. 

 As the parent-plant growing in Edinburgh was found 

 by Mr. Scott to be in a high degree sterile, it may 

 have transmitted a similar tendency to its offspring, 

 independently of their illegitimate birth. I am, how- 

 ever, inclined to attribute some weight to the illegiti- 

 macy of their descent, both from the analogy of other 

 cases, and more especially from the fact that when the 

 plants were legitimately fertilised with pollen of the 

 common primrose . they yielded an average, as may be 

 seen in the table, of only 5 more seeds than when 

 illegitimately fertilised with the same pollen. ISTow we 

 know that it is eminently characteristic of the illegiti- 

 mate offspring of Primula Sinensis that they yield but 

 few more seeds when legitimately fertilised than when 

 fertilised with their own-form pollen. 



